ASTM D2700-23b
(Test Method)Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
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. ...
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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.
Designation: D2700 − 23b
Standard Test Method for
1
Motor Octane Number of Spark-Ignition Engine Fuel
This standard is issued under the fixed designation D2700; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* calculated value shall be rounded “to the nearest unit” in the
last right-hand digit used in expressing the specified limit, in
1.1 This laboratory test method covers the quantitative
accordance with the rounding method of Practice E29.
determination of the knock rating of liquid spark-ignition
1.5 This standard does not purport to address all of the
engine fuel in terms of Motor octane number, including fuels
safety concerns, if any, associated with its use. It is the
that contain up to 25 % v/v of ethanol. However, this test
responsibility of the user of this standard to establish appro-
method may not be applicable to fuel and fuel components that
2
priate safety, health, and environmental practices and deter-
are primarily oxygenates. The sample fuel is tested in a
mine the applicability of regulatory limitations prior to use.
standardized single cylinder, four-stroke cycle, variable com-
For more specific hazard statements, see Section 8, 14.4.1,
pression ratio, carbureted, CFR engine run in accordance with
15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9),
a defined set of operating conditions. The octane number scale
A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and
is defined by the volumetric composition of primary reference
X4.5.1.8.
fuel blends. The sample fuel knock intensity is compared to
1.6 This international standard was developed in accor-
that of one or more primary reference fuel blends. The octane
dance with internationally recognized principles on standard-
number of the primary reference fuel blend that matches the
ization established in the Decision on Principles for the
knock intensity of the sample fuel establishes the Motor octane
Development of International Standards, Guides and Recom-
number.
mendations issued by the World Trade Organization Technical
1.2 The octane number scale covers the range from 0 to 120
Barriers to Trade (TBT) Committee.
octane number, but this test method has a working range from
40 to 120 octane number. Typical commercial fuels produced
2. Referenced Documents
for automotive spark-ignition engines rate in the 80 to 90
3
2.1 ASTM Standards:
Motor octane number range. Typical commercial fuels pro-
D1193 Specification for Reagent Water
duced for aviation spark-ignition engines rate in the 98 to 102
D2268 Test Method for Analysis of High-Purity n-Heptane
Motor octane number range. Testing of gasoline blend stocks
and Isooctane by Capillary Gas Chromatography
or other process stream materials can produce ratings at various
D2699 Test Method for Research Octane Number of Spark-
levels throughout the Motor octane number range.
Ignition Engine Fuel
1.3 The values of operating conditions are stated in SI units
D2885 Test Method for Determination of Octane Number of
and are considered standard. The values in parentheses are the
Spark-Ignition Engine Fuels by On-Line Direct Compari-
historical inch-pounds units. The standardized CFR engine
son Technique
measurements continue to be in inch-pound units only because
D3703 Test Method for Hydroperoxide Number of Aviation
of the extensive and expensive tooling that has been created for
Turbine Fuels, Gasoline and Diesel Fuels
this equipment.
D4057 Practice for Manual Sampling of Petroleum and
1.4 For purposes of determining conformance with all
Petroleum Products
specified limits in this standard, an observed value or a
D4175 Terminology Relating to Petroleum Products, Liquid
Fuels, and Lubricants
1 D4177 Practice for Automatic Sampling of Petroleum and
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Petroleum Products
Subcommittee D02.01 on Combustion Characteristics.
Current edition approved Nov. 1, 2023. Published January 2024. Originally
approved in 1968. Last previous edition approved in 2023 as D2700 – 23a. DOI:
3
10.1520/D2700-23B. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
2
Research octane number, determined using Test Method D2699, is a companion contact ASTM Customer Service at service@astm.org. For Ann
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2700 − 23a D2700 − 23b
Standard Test Method for
1
Motor Octane Number of Spark-Ignition Engine Fuel
This standard is issued under the fixed designation D2700; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. 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
2
applicable to fuel and fuel components that are primarily oxygenates. 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.
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.
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.01 on Combustion Characteristics.
Current edition approved Oct. 1, 2023Nov. 1, 2023. Published October 2023January 2024. Originally approved in 1968. Last previous edition approved in 2023 as
D2700 – 23.D2700 – 23a. DOI: 10.1520/D2700-23A.10.1520/D2700-23B.
2
Research octane number, determined using Test Method D2699, is a companion method to provide a similar but typically higher octane rating under milder operating
conditions.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D2700 − 23b
2. Referenced Documents
3
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D2268 Test Method for Analysis of High-Purity n-Heptane and Isooctane by Capillary Gas Chromatography
D2699 Test Method for Research Octane Number of Spark-Ignition Engine Fuel
D2885 Test Method for Determination of Octane Number
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D2700 − 23b
Standard Test Method for
1
Motor Octane Number of Spark-Ignition Engine Fuel
This standard is issued under the fixed designation D2700; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* calculated value shall be rounded “to the nearest unit” in the
last right-hand digit used in expressing the specified limit, in
1.1 This laboratory test method covers the quantitative
accordance with the rounding method of Practice E29.
determination of the knock rating of liquid spark-ignition
1.5 This standard does not purport to address all of the
engine fuel in terms of Motor octane number, including fuels
safety concerns, if any, associated with its use. It is the
that contain up to 25 % v/v of ethanol. However, this test
responsibility of the user of this standard to establish appro-
method may not be applicable to fuel and fuel components that
2
priate safety, health, and environmental practices and deter-
are primarily oxygenates. The sample fuel is tested in a
mine the applicability of regulatory limitations prior to use.
standardized single cylinder, four-stroke cycle, variable com-
For more specific hazard statements, see Section 8, 14.4.1,
pression ratio, carbureted, CFR engine run in accordance with
15.5.1, 16.6.1, Annex A1, A2.2.3.1, A2.2.3.3(6) and (9),
a defined set of operating conditions. The octane number scale
A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.12.4, and
is defined by the volumetric composition of primary reference
X4.5.1.8.
fuel blends. The sample fuel knock intensity is compared to
1.6 This international standard was developed in accor-
that of one or more primary reference fuel blends. The octane
dance with internationally recognized principles on standard-
number of the primary reference fuel blend that matches the
ization established in the Decision on Principles for the
knock intensity of the sample fuel establishes the Motor octane
Development of International Standards, Guides and Recom-
number.
mendations issued by the World Trade Organization Technical
1.2 The octane number scale covers the range from 0 to 120
Barriers to Trade (TBT) Committee.
octane number, but this test method has a working range from
40 to 120 octane number. Typical commercial fuels produced
2. Referenced Documents
for automotive spark-ignition engines rate in the 80 to 90
3
2.1 ASTM Standards:
Motor octane number range. Typical commercial fuels pro-
D1193 Specification for Reagent Water
duced for aviation spark-ignition engines rate in the 98 to 102
D2268 Test Method for Analysis of High-Purity n-Heptane
Motor octane number range. Testing of gasoline blend stocks
and Isooctane by Capillary Gas Chromatography
or other process stream materials can produce ratings at various
D2699 Test Method for Research Octane Number of Spark-
levels throughout the Motor octane number range.
Ignition Engine Fuel
1.3 The values of operating conditions are stated in SI units
D2885 Test Method for Determination of Octane Number of
and are considered standard. The values in parentheses are the
Spark-Ignition Engine Fuels by On-Line Direct Compari-
historical inch-pounds units. The standardized CFR engine
son Technique
measurements continue to be in inch-pound units only because
D3703 Test Method for Hydroperoxide Number of Aviation
of the extensive and expensive tooling that has been created for
Turbine Fuels, Gasoline and Diesel Fuels
this equipment.
D4057 Practice for Manual Sampling of Petroleum and
1.4 For purposes of determining conformance with all
Petroleum Products
specified limits in this standard, an observed value or a
D4175 Terminology Relating to Petroleum Products, Liquid
Fuels, and Lubricants
1 D4177 Practice for Automatic Sampling of Petroleum and
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Petroleum Products
Subcommittee D02.01 on Combustion Characteristics.
Current edition approved Nov. 1, 2023. Published January 2024. Originally
approved in 1968. Last previous edition approved in 2023 as D2700 – 23a. DOI:
3
10.1520/D2700-23B. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
2
Research octane number, determined using Test Method D2699, is a companion contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
method to provide a similar but typically higher octane rating under milder Standards volume information, refer to the standard’s Doc
...
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