ASTM D2885-21
(Test Method)Standard Test Method for Determination of Octane Number of Spark-Ignition Engine Fuels by On-Line Direct Comparison Technique
Standard Test Method for Determination of Octane Number of Spark-Ignition Engine Fuels by On-Line Direct Comparison Technique
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.
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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: D2885 − 21
Standard Test Method for
Determination of Octane Number of Spark-Ignition Engine
1
Fuels by On-Line Direct Comparison Technique
This standard is issued under the fixed designation D2885; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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* 1.6 The octane number difference between the stream
sample and the applicable comparison reference fuel is self-
1.1 This test method covers the quantitative online determi-
limiting by specifications imposed upon the standard and
nationbydirectcomparisonofthedifferenceinknockratingor
prototype fuels.
delta octane number of a stream sample of spark-ignition
engine fuel from that of a comparison reference fuel. 1.7 Specifications for selection, preparation, storage, and
dispensing of standard and prototype fuels are provided.
1.2 This test method covers the methodology for obtaining
Detailed procedures for determination of an appropriate as-
anoctanenumberusingthemeasureddeltaoctanenumberand
signedoctanenumberforbothstandardandprototypefuelsare
the octane number of the comparison reference fuel.
also incorporated.
1.3 The comparison reference fuel is required to be of
1.8 The values of operating conditions are stated in SI units
essentially the same composition as the stream sample to be
and are considered standard. The values in parentheses are
analyzed and can be a secondary fuel termed standard fuel or
historical inch-pound units. The standardized CFR engine
a tertiary fuel termed prototype fuel.
measurements continue to be expressed in inch-pound units
1.4 The test method utilizes a knock testing unit/automated
only because of the extensive and expensive tooling that has
analyzer system that incorporates computer control of a stan-
been created for this equipment.
dardized single-cylinder, four-stroke cycle, variable compres-
1.9 This standard does not purport to address all of the
sion ratio, carbureted, CFR engine with appropriate auxiliary
safety concerns, if any, associated with its use. It is the
equipment using either Test Method D2699 Research method
responsibility of the user of this standard to establish appro-
or Test Method D2700 Motor method operating conditions.
priate safety, health, and environmental practices and deter-
1.4.1 Knock measurements are based on operation of both
mine the applicability of regulatory limitations prior to use.
fuels at the fuel-air ratio that produces maximum knock
Formorespecificwarningstatements,seeSection8andAnnex
intensity for that fuel.
A1.
1.4.2 Measured differences in knock intensity are scaled to
1.10 This international standard was developed in accor-
provide a positive or negative delta octane number of the
dance with internationally recognized principles on standard-
stream sample from the comparison reference fuel when the
ization established in the Decision on Principles for the
fuels are compared at the same compression ratio.
Development of International Standards, Guides and Recom-
1.4.3 Measured differences in compression ratio are scaled
mendations issued by the World Trade Organization Technical
from the appropriate guide table to provide a positive or
Barriers to Trade (TBT) Committee.
negative delta octane number of the stream sample from the
comparison reference fuel when the fuels are compared at the
2. Referenced Documents
same knock intensity.
2
2.1 ASTM Standards:
1.5 This test method is limited to testing 78 to 102 octane
D1193Specification for Reagent Water
number spark-ignition engine fuels using either research or
D2699Test Method for Research Octane Number of Spark-
motor method conditions.
Ignition Engine Fuel
D2700Test Method for Motor Octane Number of Spark-
Ignition Engine Fuel
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
2
Subcommittee D02.01 on Combustion Characteristics. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJuly1,2021.PublishedJuly2021.Originallyapproved contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in 1970. Last previous edition approved in 2020 as D2885–20. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D2885-21. the ASTM website.
*A Summary of Changes section appears at the end o
...
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: D2885 − 20 D2885 − 21
Standard Test Method for
Determination of Octane Number of Spark-Ignition Engine
1
Fuels by On-Line Direct Comparison Technique
This standard is issued under the fixed designation D2885; 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 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
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 May 1, 2020July 1, 2021. Published May 2020July 2021. Originally approved in 1970. Last previous edition approved in 20192020 as
D2885 – 19b.D2885 – 20. DOI: 10.1520/D2885-20.10.1520/D2885-21.
*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
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D2885 − 21
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.
2. Referenced Documents
2
2.1 ASTM Standards:
D1193 Spe
...
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