ASTM D976-91(2000)e1
(Test Method)Standard Test Methods for Calculated Cetane Index of Distillate Fuels
Standard Test Methods for Calculated Cetane Index of Distillate Fuels
SCOPE
1.1 The Calculated Cetane Index formula represents a means for directly estimating the ASTM cetane number of distillate fuels from API gravity and mid-boiling point. The index value, as computed from the formula, is termed the Calculated Cetane Index.
1.2 The Calculated Cetane Index is not an optional method for expressing ASTM cetane number. It is a supplementary tool for predicting cetane number when used with due regard for its limitations.
1.3 The Calculated Cetane Index formula is particularly applicable to straight-run fuels, catalytically cracked stocks, and blends of the two.
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 and health practices and determine the applicability of regulatory limitations prior to use. Note 1-This test method is temporarily retained because the proposal to the U.S. EPA to control diesel fuel aromatics concentrations via a 40 Calculated Cetane Index minimum is based on the correlation between Test Method D976 and aromatics concentration. Test Method D4737 is the preferred method as estimator of cetane number. Test method D976 is intended to be letter balloted for withdrawal from the book of standards in 1993.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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An American National Standard
ϵ1
Designation: D 976 – 91 (Reapproved 2000)
Designation: 364/84
Standard Test Methods for
Calculated Cetane Index of Distillate Fuels
This standard is issued under the fixed designation D 976; 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 (ϵ) indicates an editorial change since the last revision or reapproval. This is also a standard of the Institute of
Petroleum issued under the fixed designation IP 218. The final number indicates the year of last revision.
These test methods have been approved by the sponsoring committees and accepted by the cooperating societies in accordance with
established procedures.
This standard has been approved for use by agencies of the Department of Defense.
ϵ NOTE—Editorial corrections were made throughout in April 2000.
1. Scope 2. Referenced Documents
1.1 The Calculated Cetane Index formula represents a 2.1 ASTM Standards:
means for directly estimating the ASTM cetane number of D86 Test Method for Distillation of Petroleum Products
distillate fuels from API gravity and mid-boiling point. The D 287 TestMethodforAPIGravityofCrudePetroleumand
index value, as computed from the formula, is termed the Petroleum Products (Hydrometer Method)
2 4
Calculated Cetane Index. D 613 Test Method for Cetane Number of Diesel Fuel Oil
1.2 The Calculated Cetane Index is not an optional method D 1298 TestMethodforDensity,RelativeDensity,(Specific
forexpressingASTMcetanenumber.Itisasupplementarytool Gravity), or API Gravity of Crude Petroleum and Liquid
for predicting cetane number when used with due regard for its Petroleum Products by Hydrometer Method
limitations. D 4737 Test Method for Calculated Cetane Index by Four
1.3 The Calculated Cetane Index formula is particularly Variable Equation
applicable to straight-run fuels, catalytically cracked stocks, 2.2 ASTM Adjuncts:
and blends of the two. Nomograph for Calculated Cetane Index
NOTE 1—This test method is temporarily retained because the proposal
3. Significance and Use
to the U.S. EPA to control diesel fuel aromatics concentrations via a 40
3.1 The Calculated Cetane Index is a useful tool for esti-
Calculated Cetane Index minimum is based on the correlation between
mating ASTM cetane number where a test engine is not
Test Method D 976 and aromatics concentration. Test Method
D 4737D 4737isthepreferredmethodasestimatorofcetanenumber.Test available for determining this property. It may be conveniently
method D 976 is intended to be letter balloted for withdrawal from the
employed for approximating cetane number where the quantity
book of standards in 1993.
of sample is too small for an engine rating. In cases where the
1.4 This standard does not purport to address all of the cetanenumberofafuelhasbeeninitiallyestablished,theindex
safety concerns, if any, associated with its use. It is the is useful as a cetane number check on subsequent samples of
responsibility of the user of this standard to establish appro- that fuel, provided its source and mode of manufacture remain
priate safety and health practices and determine the applica- unchanged.
bility of regulatory limitations prior to use.
4. Equation for Calculated Cetane Index
4.1 The Calculated Cetane Index is determined from the
These test methods are under the jurisdiction of ASTM Committee D02 on
following equation:
Petroleum Products and Lubricants and are the direct responsibility of Subcommit-
Calculated cetane index52420.34 1 0.016 G 1 0.192 G log M
tee D02.E on Burner, Diesel, and Gas Turbine Fuel Oils.
2 2
Current edition approved March 15, 1991. Published May 1991. Originally
1 65.01 ~log M! 2 0.0001809 M . (1)
published as D 976 – 66. Last previous edition D 976 – 80 (1990).
A method of calculating cetane index was developed by the Diesel Fuels
Division, Coordinating Fuel and Equipment Research Committee of the Coordinat- Annual Book of ASTM Standards, Vol 05.01.
ing Research Council. See H. D.Young, “Methods for Estimating Cetane Number,” Annual Book of ASTM Standards, Vol 05.05.
Proceedings, PPIRA, Am. Petroleum Inst., Vol. 30 M [III], 1950. This method was Annual Book of ASTM Standards, Vol 05.02.
revised in 1960 by Research Division I of Committee D-2 to conform to the revised CopiesoftheNomographforCalculatedCetaneIndex,8 ⁄2by11in.insize,are
Test Method D 613. available at a nominal cost from ASTM. Request
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