ASTM D2700-07a
(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
Motor O.N. correlates with commercial automotive spark-ignition engine antiknock performance under severe conditions of operation.
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 D 4814. 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:
Motor O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.
Motor O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.
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 except that this test method may not be 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.
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 and health practices and determine the applicability of regulatory limitations prior to use. For more specific hazard statements, see Section 8, 13.4.1, 14.5.1, 15.6.1, 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.
General Information
Relations
Standards Content (Sample)
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
An American National Standard
Designation: D 2700 – 07a
Designation: 236/87
Standard Test Method for
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Motor Octane Number of Spark-Ignition Engine Fuel
This standard is issued under the fixed designation D 2700; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This laboratory test method covers the quantitative
bility of regulatory limitations prior to use. For more specific
determination of the knock rating of liquid spark-ignition
hazard statements, see Section 8, 13.4.1, 14.5.1, 15.6.1,Annex
engine fuel in terms of Motor octane number except that this
A1, A2.2.3.1, A2.2.3.3(6) and (9), A2.3.5, X3.3.7, X4.2.3.1,
test method may not be applicable to fuel and fuel components
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X4.3.4.1, X4.3.9.3, X4.3.12.4, and X4.5.1.8.
that are primarily oxygenates. The sample fuel is tested in a
standardized single cylinder, four-stroke cycle, variable com-
2. Referenced Documents
pression ratio, carbureted, CFR engine run in accordance with
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2.1 ASTM Standards:
a defined set of operating conditions. The octane number scale
D 1193 Specification for Reagent Water
is defined by the volumetric composition of primary reference
D 1744 Test Method for Water in Liquid Petroleum Prod-
fuel blends. The sample fuel knock intensity is compared to
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ucts by Karl Fischer Reagent
that of one or more primary reference fuel blends. The octane
D 2268 Test Method forAnalysis of High-Purity n-Heptane
number of the primary reference fuel blend that matches the
and Isooctane by Capillary Gas Chromatography
knock intensity of the sample fuel establishes the Motor octane
D 2360 Test Method for Trace Impurities in Monocyclic
number.
Aromatic Hydrocarbons by Gas Chromatography
1.2 The octane number scale covers the range from 0 to 120
D2699 Test Method for Research Octane Number of
octane number, but this test method has a working range from
Spark-Ignition Engine Fuel
40 to 120 octane number. Typical commercial fuels produced
D 2885 Test Method for Determination of Octane Number
for automotive spark-ignition engines rate in the 80 to 90
of Spark-Ignition Engine Fuels by On-Line Direct Com-
Motor octane number range. Typical commercial fuels pro-
parison Technique
duced for aviation spark-ignition engines rate in the 98 to 102
D 3703 Test Method for Peroxide Number of Aviation
Motor octane number range. Testing of gasoline blend stocks
Turbine Fuels
orotherprocessstreammaterialscanproduceratingsatvarious
D 4057 Practice for Manual Sampling of Petroleum and
levels throughout the Motor octane number range.
Petroleum Products
1.3 The values of operating conditions are stated in SI units
D 4175 Terminology Relating to Petroleum, Petroleum
and are considered standard. The values in parentheses are the
Products, and Lubricants
historical inch-pounds units. The standardized CFR engine
D 4177 Practice for Automatic Sampling of Petroleum and
measurements continue to be in inch-pound units only because
Petroleum Products
oftheextensiveandexpensivetoolingthathasbeencreatedfor
D 4814 SpecificationforAutomotiveSpark-IgnitionEngine
this equipment.
Fuel
1.4 This standard does not purport to address all of the
D 5842 Practice for Sampling and Handling of Fuels for
safety concerns, if any, associated with its use. It is the
Volatility Measurement
E 344 Terminology Relating to Thermometry and Hydrom-
etry
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This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.01 on Combustion Characteristics.
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Current edition approved March 1, 2007. Published March 2007. Originally
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 1968. Last previous edition approved in 2007 as D 2700–07.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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Research octane number, determined using Test Method D 2699, is a compan-
Standards volume information, refer to the standard’s Document Summary page on
ion method to provide a similar but typically higher octane rating under milder
the ASTM website.
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operating conditions.
Withdrawn.
*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.
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D 2700 – 07a
E 456 Terminology Relating
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