D02.01 - Combustion Characteristics

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The ID and CD values and the DCN value determined by this test method provides a measure of the ignition characteristics of diesel fuel oil used in compression ignition engines.  
5.2 This test can be used by engine manufacturers, petroleum refiners and marketers, and in commerce as a specification aid to relate or match fuels and engines.  
5.3 The relationship of diesel fuel oil DCN determinations to the performance of full-scale, variable-speed, variable-load diesel engines is not completely understood.  
5.4 This test can be applied to non-conventional diesel fuels.  
5.5 This test determines ignition characteristics and requires a sample of approximately 370 mL and a test time of approximately 30 min using a fit-for-use instrument.
SCOPE
1.1 This test method covers the quantitative determination of the derived cetane number of conventional diesel fuel oils, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of Specification D975, Grades No.1-D and 2-D regular, low and ultra-low-sulfur diesel fuel oils, European standard EN590, and Canadian standards CAN/CGSB-3.517, CAN/CGSB-3.520, and CAN/CGSB-3.522. The test method may be applied to the quantitative determination of the derived cetane number of biodiesel, blends of diesel fuel oils containing biodiesel material (for example, Specifications D975, D6751, and D7467), and diesel fuel oil blending components.  
1.2 This test method utilizes a constant volume combustion chamber with direct fuel injection into heated, compressed synthetic air. A dynamic pressure wave is produced from the combustion of the sample. An equation converts the ignition delay and the combustion delay determined from the dynamic pressure curve to a derived cetane number (DCN).  
1.3 This test method covers the ignition delay ranging from 1.9 ms to 25 ms and combustion delay ranging from 2.5 ms to 160 ms (30 DCN to 70 DCN). However, the precision stated only covers the range of DCN results from 38.45 to 64.35.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The ID and DCN values determined by this test method can provide a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test can be used in commerce as a specification aid to relate or match fuels and engines. It can also be useful in research or when there is interest in the ignition delay of a diesel fuel under the conditions of this test method.  
5.3 The relationship of diesel fuel oil DCN determinations to the performance of full-scale, variable-speed, variable-load diesel engines is not completely understood.  
5.4 This test may be applied to non-conventional fuels. It is recognized that the performance of non-conventional fuels in full-scale engines is not completely understood. The user is therefore cautioned to investigate the suitability of ignition characteristic measurements for predicting performance in full-scale engines for these types of fuels.  
5.5 This test determines ignition characteristics and requires a sample of approximately 100 mL and a test time of approximately 20 min on a fit-for-use instrument.
SCOPE
1.1 This automated laboratory test method covers the quantitative determination of the ignition characteristics of conventional diesel fuel oil, oil-sands based fuels, hydrocarbon oils, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of ASTM Specification D975 grades No. 1-D S15, No. 1-D S500, and No. 1-D S5000, and grades No. 2-D S15, No. 2-D S500, and No. 2-D S5000 diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and 3.520. The test method may also be applied to the quantitative determination of the ignition characteristics of diesel fuel blending components.  
1.2 This test method measures the ignition delay of a diesel fuel injected directly into a constant volume combustion chamber containing heated, compressed air. An equation correlates an ignition delay determination to cetane number by Test Method D613, resulting in a derived cetane number (DCN).  
1.3 This test method covers the ignition delay range from 2.64 ms to 6.90 ms (75.1 DCN to 31.5 DCN). The combustion analyzer can measure shorter and longer ignition delays, but precision may be affected. For these shorter or longer ignition delays the correlation equation for DCN is given in Appendix X2.  
1.4 For purposes of determining conformance with the parameters of this test method, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the parameter, in accordance with the rounding method of Practice E29.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The ICN value determined by this test method provides a measure of the ignition characteristics of diesel fuel oil used in compression ignition engines.  
5.2 This test can be used by engine manufacturers, petroleum refiners, fuel producers and in commerce as a specification aid to relate or match fuels and engines.  
5.3 The relationship of diesel fuel ICN determinations to the full scale, variable speed, variable load diesel engine is not completely understood.  
5.4 This test can be applied to non-conventional diesel fuels.  
5.5 This test determines ICN; it requires a sample of approximately 40 mL and a test time of approximately 25 min.  
5.6 This test method is based on the Energy Institute Test Method IP 617.
SCOPE
1.1 This test method covers the quantitative determination of the indicated cetane number (ICN) of conventional diesel fuel oils, and diesel fuel oils containing cetane number improver additives; it is applicable to products typical of Specification D975, Grades No.1-D and 2-D diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and CAN/CGSB-3.520. The test method is also applicable to biodiesel, blends of diesel fuel oils containing biodiesel material (for example, materials as specified in Specifications D975, D6751, D7467 and European standards EN 14214, EN 16734, and EN 16709), diesel fuels from non-petroleum origin, hydrocarbon oils, diesel fuel oil blending components, aviation turbine fuels, and polyoxymethylene dimethyl ether (OME).  
1.2 This test method utilizes a constant volume combustion chamber (CVCC) with direct fuel injection into heated compressed air. The apparatus is calibrated using blends of reference fuels. ICN is determined directly from ignition delay using an instrument specific reference fuel calibration curve.  
1.3 This test method and its precision cover the calibrated range of 35 ICN to 85 ICN, inclusive. The analyzer can measure ICN outside the calibrated range, but the precision has not been determined.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Supercharge method ratings can provide an indication of the rich-mixture antiknock performance of aviation gasoline in aviation piston engines.  
5.2 Supercharge method ratings are used by petroleum refiners and marketers and in commerce as a primary specification measurement to ensure proper matching of fuel antiknock quality and engine requirement.  
5.3 Supercharge method ratings may be used by aviation engine and aircraft manufacturers as a specification measurement related to matching of fuels and engines.
SCOPE
1.1 This laboratory test method covers the quantitative determination of supercharge ratings of spark-ignition aviation gasoline. The sample fuel is tested using a standardized single cylinder, four-stroke cycle, indirect injected, liquid cooled, CFR engine run in accordance with a defined set of operating conditions.  
1.2 The supercharge rating is calculated by linear interpolation of the knock limited power of the sample compared to the knock limited power of bracketing reference fuel blends.  
1.3 The rating scale covers the range from 85 octane number to Isooctane + 6.0 mL TEL/U.S. gal.  
1.4 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements and reference fuel concentrations continue to be in historical units.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Annex A1.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The delta octane number (ΔO.N.) measure can quantify the difference of in-line blended spark-ignition engine fuel or process stream material octane number to a desired octane number to aid in optimizing control of blender facilities or refinery process units.  
5.2 The ΔO.N. measure, summed with a comparison reference fuels O.N. provides either research or motor octane number value of the current in-line blended spark-ignition engine fuel or process stream material.  
5.3 Through the use of cumulative flow-proportioned averaging of the repetitive ΔO.N. results, in accordance with Practice D6624, an average octane number can be assigned to a tender or batch of in-line blended spark-ignition engine fuel.
SCOPE
1.1 This test method covers the quantitative online determination by direct comparison of the difference in knock rating or delta octane number of a stream sample of spark-ignition engine fuel from that of a comparison reference fuel.  
1.2 This test method covers the methodology for obtaining an octane number using the measured delta octane number and the octane number of the comparison reference fuel.  
1.3 The comparison reference fuel is required to be of essentially the same composition as the stream sample to be analyzed and can be a secondary fuel termed standard fuel or a tertiary fuel termed prototype fuel.  
1.4 The test method utilizes a knock testing unit/automated analyzer system that incorporates computer control of a standardized single-cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine with appropriate auxiliary equipment using either Test Method D2699 Research method or Test Method D2700 Motor method operating conditions.  
1.4.1 Knock measurements are based on operation of both fuels at the fuel-air ratio that produces maximum knock intensity for that fuel.  
1.4.2 Measured differences in knock intensity are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same compression ratio.  
1.4.3 Measured differences in compression ratio are scaled from the appropriate guide table to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same knock intensity.  
1.5 This test method is limited to testing 78 to 102 octane number spark-ignition engine fuels using either research or motor method conditions.  
1.6 The octane number difference between the stream sample and the applicable comparison reference fuel is self-limiting by specifications imposed upon the standard and prototype fuels.  
1.7 Specifications for selection, preparation, storage, and dispensing of standard and prototype fuels are provided. Detailed procedures for determination of an appropriate assigned octane number for both standard and prototype fuels are also incorporated.  
1.8 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are historical inch-pound units. The standardized CFR engine measurements continue to be expressed in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Section 8 and Annex A1.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Supercharge method ratings can provide an indication of the rich-mixture antiknock performance of aviation gasoline in aviation piston engines.  
5.2 Supercharge method ratings are used by petroleum refiners and marketers and in commerce as a primary specification measurement to ensure proper matching of fuel antiknock quality and engine requirement.  
5.3 Supercharge method ratings may be used by aviation engine and aircraft manufacturers as a specification measurement related to matching of fuels and engines.
SCOPE
1.1 This laboratory test method covers the quantitative determination of supercharge ratings of spark-ignition aviation gasoline. The sample fuel is tested using a standardized single cylinder, four-stroke cycle, indirect injected, liquid cooled, CFR engine run in accordance with a defined set of operating conditions.  
1.2 The supercharge rating is calculated by linear interpolation of the knock limited power of the sample compared to the knock limited power of bracketing reference fuel blends.  
1.3 The rating scale covers the range from 85 octane number to Isooctane + 6.0 mL TEL/U.S. gal.  
1.4 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements and reference fuel concentrations continue to be in historical units.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Annex A1.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 The ID and DCN values determined by this test method can provide a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test can be used in commerce as a specification aid to relate or match fuels and engines. It can also be useful in research or when there is interest in the ignition delay of a diesel fuel under the conditions of this test method.  
5.3 The relationship of diesel fuel oil DCN determinations to the performance of full-scale, variable-speed, variable-load diesel engines is not completely understood.  
5.4 This test may be applied to non-conventional fuels. It is recognized that the performance of non-conventional fuels in full-scale engines is not completely understood. The user is therefore cautioned to investigate the suitability of ignition characteristic measurements for predicting performance in full-scale engines for these types of fuels.  
5.5 This test determines ignition characteristics and requires a sample of approximately 100 mL and a test time of approximately 20 min on a fit-for-use instrument.
SCOPE
1.1 This automated laboratory test method covers the quantitative determination of the ignition characteristics of conventional diesel fuel oil, oil-sands based fuels, hydrocarbon oils, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of ASTM Specification D975 grades No. 1-D S15, No. 1-D S500, and No. 1-D S5000, and grades No. 2-D S15, No. 2-D S500, and No. 2-D S5000 diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and 3.520. The test method may also be applied to the quantitative determination of the ignition characteristics of diesel fuel blending components.  
1.2 This test method measures the ignition delay of a diesel fuel injected directly into a constant volume combustion chamber containing heated, compressed air. An equation correlates an ignition delay determination to cetane number by Test Method D613, resulting in a derived cetane number (DCN).  
1.3 This test method covers the ignition delay range from 2.64 ms to 6.90 ms (75.1 DCN to 31.5 DCN). The combustion analyzer can measure shorter and longer ignition delays, but precision may be affected. For these shorter or longer ignition delays the correlation equation for DCN is given in Appendix X2.  
1.4 For purposes of determining conformance with the parameters of this test method, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the parameter, in accordance with the rounding method of Practice E29.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The delta octane number (ΔO.N.) measure can quantify the difference of in-line blended spark-ignition engine fuel or process stream material octane number to a desired octane number to aid in optimizing control of blender facilities or refinery process units.  
5.2 The ΔO.N. measure, summed with a comparison reference fuels O.N. provides either research or motor octane number value of the current in-line blended spark-ignition engine fuel or process stream material.  
5.3 Through the use of cumulative flow-proportioned averaging of the repetitive ΔO.N. results, in accordance with Practice D6624, an average octane number can be assigned to a tender or batch of in-line blended spark-ignition engine fuel.
SCOPE
1.1 This test method covers the quantitative online determination by direct comparison of the difference in knock rating or delta octane number of a stream sample of spark-ignition engine fuel from that of a comparison reference fuel.  
1.2 This test method covers the methodology for obtaining an octane number using the measured delta octane number and the octane number of the comparison reference fuel.  
1.3 The comparison reference fuel is required to be of essentially the same composition as the stream sample to be analyzed and can be a secondary fuel termed standard fuel or a tertiary fuel termed prototype fuel.  
1.4 The test method utilizes a knock testing unit/automated analyzer system that incorporates computer control of a standardized single-cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine with appropriate auxiliary equipment using either Test Method D2699 Research method or Test Method D2700 Motor method operating conditions.  
1.4.1 Knock measurements are based on operation of both fuels at the fuel-air ratio that produces maximum knock intensity for that fuel.  
1.4.2 Measured differences in knock intensity are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same compression ratio.  
1.4.3 Measured differences in compression ratio are scaled from the appropriate guide table to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same knock intensity.  
1.5 This test method is limited to testing 78 to 102 octane number spark-ignition engine fuels using either research or motor method conditions.  
1.6 The octane number difference between the stream sample and the applicable comparison reference fuel is self-limiting by specifications imposed upon the standard and prototype fuels.  
1.7 Specifications for selection, preparation, storage, and dispensing of standard and prototype fuels are provided. Detailed procedures for determination of an appropriate assigned octane number for both standard and prototype fuels are also incorporated.  
1.8 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are historical inch-pound units. The standardized CFR engine measurements continue to be expressed in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Section 8 and Annex A1.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The delta octane number (ΔO.N.) measure can quantify the difference of in-line blended spark-ignition engine fuel or process stream material octane number to a desired octane number to aid in optimizing control of blender facilities or refinery process units.  
5.2 The ΔO.N. measure, summed with a comparison reference fuels O.N. provides either research or motor octane number value of the current in-line blended spark-ignition engine fuel or process stream material.  
5.3 Through the use of cumulative flow-proportioned averaging of the repetitive ΔO.N. results, in accordance with Practice D6624, an average octane number can be assigned to a tender or batch of in-line blended spark-ignition engine fuel.
SCOPE
1.1 This test method covers the quantitative online determination by direct comparison of the difference in knock rating or delta octane number of a stream sample of spark-ignition engine fuel from that of a comparison reference fuel.  
1.2 This test method covers the methodology for obtaining an octane number using the measured delta octane number and the octane number of the comparison reference fuel.  
1.3 The comparison reference fuel is required to be of essentially the same composition as the stream sample to be analyzed and can be a secondary fuel termed standard fuel or a tertiary fuel termed prototype fuel.  
1.4 The test method utilizes a knock testing unit/automated analyzer system that incorporates computer control of a standardized single-cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine with appropriate auxiliary equipment using either Test Method D2699 Research method or Test Method D2700 Motor method operating conditions.  
1.4.1 Knock measurements are based on operation of both fuels at the fuel-air ratio that produces maximum knock intensity for that fuel.  
1.4.2 Measured differences in knock intensity are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same compression ratio.  
1.4.3 Measured differences in compression ratio are scaled from the appropriate guide table to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same knock intensity.  
1.5 This test method is limited to testing 78 to 102 octane number spark-ignition engine fuels using either research or motor method conditions.  
1.6 The octane number difference between the stream sample and the applicable comparison reference fuel is self-limiting by specifications imposed upon the standard and prototype fuels.  
1.7 Specifications for selection, preparation, storage, and dispensing of standard and prototype fuels are provided. Detailed procedures for determination of an appropriate assigned octane number for both standard and prototype fuels are also incorporated.  
1.8 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are historical inch-pound units. The standardized CFR engine measurements continue to be expressed in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Section 8 and Annex A1.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The delta octane number (ΔO.N.) measure can quantify the difference of in-line blended spark-ignition engine fuel or process stream material octane number to a desired octane number to aid in optimizing control of blender facilities or refinery process units.  
5.2 The ΔO.N. measure, summed with a statistically sound comparison reference fuels O.N. provides either research or motor octane number value of the current in-line blended spark-ignition engine fuel or process stream material.  
5.3 Through the use of cumulative flow-weighted averaging of the repetitive ΔO.N. results, a statistically significant octane number can be assigned to a tender or batch of in-line blended spark-ignition engine fuel.
SCOPE
1.1 This test method covers the quantitative online determination by direct comparison of the difference in knock rating or delta octane number of a stream sample of spark-ignition engine fuel from that of a comparison reference fuel.  
1.2 This test method covers the methodology for obtaining an octane number using the measured delta octane number and the octane number of the comparison reference fuel.  
1.3 The comparison reference fuel is required to be of essentially the same composition as the stream sample to be analyzed and can be a secondary fuel termed standard fuel or a tertiary fuel termed prototype fuel.  
1.4 The test method utilizes a knock testing unit/automated analyzer system that incorporates computer control of a standardized single-cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine with appropriate auxiliary equipment using either Test Method D2699 Research method or Test Method D2700 Motor method operating conditions.  
1.4.1 Knock measurements are based on operation of both fuels at the specific fuel-air ratio that produces maximum knock intensity for that fuel.  
1.4.2 Measured differences in knock intensity are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same compression ratio.  
1.4.3 Measured differences in compression ratio are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same knock intensity.  
1.5 This test method is limited to testing 78 to 102 octane number spark-ignition engine fuels using either research or motor method conditions.  
1.6 The octane number difference between the stream sample and the applicable comparison reference fuel is self-limiting by specifications imposed upon the standard and prototype fuels.  
1.7 Specifications for selection, preparation, storage, and dispensing of standard and prototype fuels are provided. Detailed procedures for determination of an appropriate assigned octane number for both standard and prototype fuels are also incorporated.  
1.8 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are historical inch-pound units. The standardized CFR engine measurements continue to be expressed in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Section 8 and Annex A1.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 The delta octane number (ΔO.N.) measure can quantify the difference of in-line blended spark-ignition engine fuel or process stream material octane number to a desired octane number to aid in optimizing control of blender facilities or refinery process units.  
5.2 The ΔO.N. measure, summed with a statistically sound comparison reference fuels O.N. provides either research or motor octane number value of the current in-line blended spark-ignition engine fuel or process stream material.  
5.3 Through the use of cumulative flow-weighted averaging of the repetitive ΔO.N. results, a statistically significant octane number can be assigned to a tender or batch of in-line blended spark-ignition engine fuel.
SCOPE
1.1 This test method covers the quantitative online determination by direct comparison of the difference in knock rating or delta octane number of a stream sample of spark-ignition engine fuel from that of a comparison reference fuel.  
1.2 This test method covers the methodology for obtaining an octane number using the measured delta octane number and the octane number of the comparison reference fuel.  
1.3 The comparison reference fuel is required to be of essentially the same composition as the stream sample to be analyzed and can be a secondary fuel termed standard fuel or a tertiary fuel termed prototype fuel.  
1.4 The test method utilizes a knock testing unit/automated analyzer system that incorporates computer control of a standardized single-cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine with appropriate auxiliary equipment using either Test Method D2699 Research method or Test Method D2700 Motor method operating conditions.  
1.4.1 Knock measurements are based on operation of both fuels at the specific fuel-air ratio that produces maximum knock intensity for that fuel.  
1.4.2 Measured differences in knock intensity are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same compression ratio.  
1.4.3 Measured differences in compression ratio are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same knock intensity.  
1.5 This test method is limited to testing 78 to 102 octane number spark-ignition engine fuels using either research or motor method conditions.  
1.6 The octane number difference between the stream sample and the applicable comparison reference fuel is self-limiting by specifications imposed upon the standard and prototype fuels.  
1.7 Specifications for selection, preparation, storage, and dispensing of standard and prototype fuels are provided. Detailed procedures for determination of an appropriate assigned octane number for both standard and prototype fuels are also incorporated.  
1.8 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are historical inch-pound units. The standardized CFR engine measurements continue to be expressed in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Section 8 and Annex A1.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8. ...

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The ID and DCN values determined by this test method can provide a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test can be used in commerce as a specification aid to relate or match fuels and engines. It can also be useful in research or when there is interest in the ignition delay of a diesel fuel under the conditions of this test method.  
5.3 The relationship of diesel fuel oil DCN determinations to the performance of full-scale, variable-speed, variable-load diesel engines is not completely understood.  
5.4 This test may be applied to non-conventional fuels. It is recognized that the performance of non-conventional fuels in full-scale engines is not completely understood. The user is therefore cautioned to investigate the suitability of ignition characteristic measurements for predicting performance in full-scale engines for these types of fuels.  
5.5 This test determines ignition characteristics and requires a sample of approximately 100 mL and a test time of approximately 20 min on a fit-for-use instrument.
SCOPE
1.1 This automated laboratory test method covers the quantitative determination of the ignition characteristics of conventional diesel fuel oil, oil-sands based fuels, hydrocarbon oils, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of ASTM Specification D975 grades No. 1-D S15, No. 1-D S500, and No. 1-D S5000, and grades No. 2-D S15, No. 2-D S500, and No. 2-D S5000 diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and 3.520. The test method may also be applied to the quantitative determination of the ignition characteristics of diesel fuel blending components.  
1.2 This test method measures the ignition delay of a diesel fuel injected directly into a constant volume combustion chamber containing heated, compressed air. An equation correlates an ignition delay determination to cetane number by Test Method D613, resulting in a derived cetane number (DCN).  
1.3 This test method covers the ignition delay range from 2.64 ms to 6.90 ms (75.1 DCN to 31.5 DCN). The combustion analyzer can measure shorter and longer ignition delays, but precision may be affected. For these shorter or longer ignition delays the correlation equation for DCN is given in Appendix X2.  
1.4 For purposes of determining conformance with the parameters of this test method, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the parameter, in accordance with the rounding method of Practice E29.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 For purposes of determining conformance with all specified limits in this standard, an observed value or a calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the specified limit, in accordance with the rounding method of Practice E29.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Gu...

SIGNIFICANCE AND USE
5.1 Supercharge method ratings can provide an indication of the rich-mixture antiknock performance of aviation gasoline in aviation piston engines.  
5.2 Supercharge method ratings are used by petroleum refiners and marketers and in commerce as a primary specification measurement to ensure proper matching of fuel antiknock quality and engine requirement.  
5.3 Supercharge method ratings may be used by aviation engine and aircraft manufacturers as a specification measurement related to matching of fuels and engines.
SCOPE
1.1 This laboratory test method covers the quantitative determination of supercharge ratings of spark-ignition aviation gasoline. The sample fuel is tested using a standardized single cylinder, four-stroke cycle, indirect injected, liquid cooled, CFR engine run in accordance with a defined set of operating conditions.  
1.2 The supercharge rating is calculated by linear interpolation of the knock limited power of the sample compared to the knock limited power of bracketing reference fuel blends.  
1.3 The rating scale covers the range from 85 octane number to Isooctane + 6.0 mL TEL/U.S. gal.  
1.4 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements and reference fuel concentrations continue to be in historical units.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Annex A1.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Supercharge method ratings can provide an indication of the rich-mixture antiknock performance of aviation gasoline in aviation piston engines.  
5.2 Supercharge method ratings are used by petroleum refiners and marketers and in commerce as a primary specification measurement to ensure proper matching of fuel antiknock quality and engine requirement.  
5.3 Supercharge method ratings may be used by aviation engine and aircraft manufacturers as a specification measurement related to matching of fuels and engines.
SCOPE
1.1 This laboratory test method covers the quantitative determination of supercharge ratings of spark-ignition aviation gasoline. The sample fuel is tested using a standardized single cylinder, four-stroke cycle, indirect injected, liquid cooled, CFR engine run in accordance with a defined set of operating conditions.  
1.2 The supercharge rating is calculated by linear interpolation of the knock limited power of the sample compared to the knock limited power of bracketing reference fuel blends.  
1.3 The rating scale covers the range from 85 octane number to Isooctane + 6.0 mL TEL/U.S. gal.  
1.4 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements and reference fuel concentrations continue to be in historical units.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Annex A1.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.  
5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1,  k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.  
5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.
This is more commonly presented as:
5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.  
5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.  
1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.7
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Bar...

SIGNIFICANCE AND USE
5.1 The ICN value determined by this test method provides a measure of the ignition characteristics of diesel fuel oil used in compression ignition engines.  
5.2 This test can be used by engine manufacturers, petroleum refiners, fuel producers and in commerce as a specification aid to relate or match fuels and engines.  
5.3 The relationship of diesel fuel ICN determinations to the full scale, variable speed, variable load diesel engine is not completely understood.  
5.4 This test can be applied to non-conventional diesel fuels.  
5.5 This test determines ICN; it requires a sample of approximately 40 mL and a test time of approximately 25 min.  
5.6 This test method is based on the Energy Institute Test Method IP 617.
SCOPE
1.1 This test method covers the quantitative determination of the indicated cetane number (ICN) of conventional diesel fuel oils, and diesel fuel oils containing cetane number improver additives; it is applicable to products typical of Specification D975, Grades No.1-D and 2-D diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and CAN/CGSB-3.520. The test method is also applicable to biodiesel, blends of diesel fuel oils containing biodiesel material (for example, materials as specified in Specifications D975, D6751, D7467 and European standards EN 14214, EN 16734, and EN 16709), diesel fuels from non-petroleum origin, hydrocarbon oils, diesel fuel oil blending components, aviation turbine fuels, and polyoxymethylene dimethyl ether (OME).  
1.2 This test method utilizes a constant volume combustion chamber (CVCC) with direct fuel injection into heated compressed air. The apparatus is calibrated using blends of reference fuels. ICN is determined directly from ignition delay using an instrument specific reference fuel calibration curve.  
1.3 This test method and its precision cover the calibrated range of 35 ICN to 85 ICN, inclusive. The analyzer can measure ICN outside the calibrated range, but the precision has not been determined.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.8
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Bar...

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The cetane number provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines.  
5.2 This test method is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to matching of fuels and engines.  
5.3 Cetane number is determined at constant speed in a precombustion chamber type compression ignition test engine. The relationship of test engine performance to full scale, variable speed, variable load engines is not completely understood.  
5.4 This test method may be used for unconventional fuels such as synthetics, vegetable oils, and the like. However, the relationship to the performance of such materials in full scale engines is not completely understood.
SCOPE
1.1 This test method covers the determination of the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.  
1.2 The cetane number scale covers the range from zero (0) to 100, but typical testing is in the range of 30 to 65 cetane number.  
1.3 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the historical inch-pound units for information only. In addition, the engine measurements continue to be in inch-pound units because of the extensive and expensive tooling that has been created for these units.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Annex A1.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.  
5.2 Motor O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.  
5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:
Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-octane number determinations.  
5.2.2 Motor O.N., in conjunction with Research O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the road octane ratings for many vehicles, is posted on retail dispensing pumps in the United States, and is referred to in vehicle manuals.
This is more commonly presented as:
5.3 Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.  
5.4 Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.  
5.5 Motor O.N. is utilized to determine, by correlation equation, the Aviation method O.N. or performance number (lean-mixture aviation rating) of aviation spark-ignition engine fuel.8
SCOPE
1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number, including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested in a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The octane number scale is defined by the volumetric composition of primary reference fuel blends. The sample fuel knock intensity is compared to that of one or more primary reference fuel blends. The octane number of the primary reference fuel blend that matches the knock intensity of the sample fuel establishes the Motor octane number.  
1.2 The octane number scale covers the range from 0 to 120 octane number, but this test method has a working range from 40 to 120 octane number. Typical commercial fuels produced for automotive spark-ignition engines rate in the 80 to 90 Motor octane number range. Typical commercial fuels produced for aviation spark-ignition engines rate in the 98 to 102 Motor octane number range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Motor octane number range.  
1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pounds units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 14.4.1, 15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Bar...

SIGNIFICANCE AND USE
5.1 Supercharge method ratings can provide an indication of the rich-mixture antiknock performance of aviation gasoline in aviation piston engines.  
5.2 Supercharge method ratings are used by petroleum refiners and marketers and in commerce as a primary specification measurement to ensure proper matching of fuel antiknock quality and engine requirement.  
5.3 Supercharge method ratings may be used by aviation engine and aircraft manufacturers as a specification measurement related to matching of fuels and engines.
SCOPE
1.1 This laboratory test method covers the quantitative determination of supercharge ratings of spark-ignition aviation gasoline. The sample fuel is tested using a standardized single cylinder, four-stroke cycle, indirect injected, liquid cooled, CFR engine run in accordance with a defined set of operating conditions.  
1.2 The supercharge rating is calculated by linear interpolation of the knock limited power of the sample compared to the knock limited power of bracketing reference fuel blends.  
1.3 The rating scale covers the range from 85 octane number to Isooctane + 6.0 mL TEL/U.S. gal.  
1.4 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements and reference fuel concentrations continue to be in historical units.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Annex A1.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.