ASTM D2885-95(1999)
(Test Method)Standard Test Method for Research and Motor Method Octane Ratings Using On-Line Analyzers
Standard Test Method for Research and Motor Method Octane Ratings Using On-Line Analyzers
SCOPE
1.1 This test method covers the calibration and use of automatic analyzers for determining the antiknock quality of motor gasolines [black-box]. Octane numbers from analyzers operated in accordance with this test method are equivalent to ASTM research or motor method octane numbers.
1.2 In this test method, inch-pound units are the preferred system of measurement.
1.3 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.
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Standards Content (Sample)
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An American National Standard
Designation: D 2885 – 95 (Reapproved 1999)
Designation: 360/96
Standard Test Method for
Research and Motor Method Octane Ratings Using On-Line
Analyzers
This standard is issued under the fixed designation D 2885; 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.
1. Scope 3.1.1 octane number, n— for spark-ignition engine fuel, any
one of several numerical indicators of resistance to knock
1.1 This test method covers the calibration and use of
obtained by comparison with reference fuels in standardized
automatic analyzers for determining the antiknock quality of
engine or vehicle tests.
motor gasolines. Octane numbers from analyzers operated in
3.1.1.1 Discussion—In the context of this test method,
accordance with this test method are equivalent to ASTM
octane number is understood to mean the numerical indicator
research or motor method octane numbers.
of knock obtained by comparison with primary reference fuels
1.2 In this test method, inch-pound units are the preferred
in a standardized CFR engine operating under conditions
system of measurement.
specified in either the Research, Test Method D 2699, or
1.3 This standard does not purport to address all of the
Motor, Test Method D 2700, standards.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 analyzer lag or response time—the time required for a
priate safety and health practices and determine the applica-
knock testing unit/analyzer system to evaluate sample fuel
bility of regulatory limitations prior to use.
quality and produce a DO.N. output signal. It includes mea-
2. Referenced Documents surements of both fuels for one complete comparison cycle.
3.2.2 check fuels (A and B)—a pair of spark-ignition engine
2.1 ASTM Standards:
fuels or process unit materials used for system qualification,
D 2699 Test Method for Research Octane Number of
typical of the products to be measured in terms of commercial
Spark-Ignition Engine Fuel
grade or process unit characteristics. Each fuel shall be
D 2700 Test Method for Motor Octane Number of Spark-
round-robin octane number (O.N.) calibrated using primary
Ignition Engine Fuel
reference fuels, multiple engines, and so forth, to establish the
D 4057 Practice for Manual Sampling of Petroleum and
expected difference O.N. for the fuel pair.
Petroleum Products
3.2.3 delta O.N. (DO.N.)—the octane difference between
E 178 Practice for Dealing With Outlying Observations
two fuels as tested by the procedures of this test method.
3. Terminology
3.2.4 expected difference O.N.—the octane difference be-
tween two check fuels of a pair, based on the average results of
3.1 Definitions:
round-robin calibrations, and expressed as a positive DO.N.
value.
This test method is under the jurisdiction of ASTM Committee D-2 on
3.2.5 octane span or calibration—the octane number scal-
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
ing or adjustment of the knock testing unit variable used to
D02.01 on Combustion Characteristics.
measure relative octane quality. This can be in terms of either
Current edition approved Jan. 15, 1995. Published February 1996. Originally
published as D 2885 – 70 T. Last previous edition D 2885 – 93. compression ratio digital counter units or knock intensity units
“Research method” refers to ASTM Test Method D 2699, Test Method for
per octane number.
Knock Characteristics of Motor Fuels by the Research Method. “Motor method”
3.2.6 overall system response time—the time required from
refers to ASTM Test Method D 2700, Test Method for Knock Characteristics of
a process, pipe line, or in-line blender change until that change
Motor and Aviation Fuels by the Motor Method. Test Methods D 2699 and D 2700
can be found in this volume.
can be displayed as a DO.N. value. It includes the time for the
Annual Book of ASTM Standards, Vol 05.05.
slowest reacting process variable, the sampling system time,
Annual Book of ASTM Standards, Vol 05.02.
5 and the knock testing/analyzer response time.
Annual Book of ASTM Standards, Vol 14.02.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 2885 – 95 (1999)
3.2.7 product O.N.—the research or motor octane number 5. Significance and Use
that can result from utilization of DO.N. value produced by this
5.1 This test method provides automatic, on-line analysis by
test method and the output signal of an automatic analyzer.
either research or motor method conditions of test. Gasoline
3.2.7.1 Discussion—In the context of this test method,
antiknock quality as determined by this technique has the same
typical commercial analyzer instrumentation provides the ca- significance as that provided in Test Method D 2699, and Test
pability to display and record the octane number obtained by Method D 2700. This test method is used by petroleum refiners
as a primary specification measurement.
adding the DO.N., produced by this test method, to the
calibrated octane number of one of the two fuels compared by
6. Reference Materials
this test method. These knock testing unit/analyzer systems
also can express the product octane number in terms of the
6.1 Primary Reference Fuels, isooctane and n-heptane
following relationship:
meeting the specifications which follow:
6.1.1 isooctane shall be no less than 99.75 % by volume
product O.N. 5 prototype O.N. 6 offset O.N.1DO.N. (1)
pure, contain no more than 0.10 % by volume n-heptane, and
where the offset O.N. represents the difference between the desired
contain no more than 0.002 g/US gal (0.5 mg/L) of lead.
product O.N. and the octane number of the calibrated fuel.
6.1.2 n-heptane shall be no less than 99.75 % by volume
pure, contain no more than 0.10 % by volume isooctane and
3.2.8 prototype fuel—a spark-ignition engine fuel or process
contain no more than 0.002 g/US gal (0.5 mg/L) of lead.
unit material which is used as a secondary standard. It is
6.2 Standard Fuel, is the basic reference for establishing the
assigned an octane number based on a direct match comparison
octane number level that defines the product octane number
with a standard fuel.
determined by automatic engine/analyzer systems. The char-
3.2.9 sample fuel—the fuel to be evaluated, which is typi-
acteristics, storage and handling procedures, calibration and
cally drawn from a flowing stream of either finished spark-
use of a standard fuel shall conform to the following:
ignition engine fuel product or a process unit material. It must
6.2.1 Octane Number shall be selected such that the
be continuously representative of the quality being produced
prototype fuels to be calibrated shall not differ from it by more
and suitably treated to eliminate any dirt or entrained moisture
than 60.5 octane number.
without affecting the octane number.
6.2.2 Volatility is not critical as long as the standard fuel has
3.2.10 standard fuel—a spark-ignition engine fuel or pro-
the full boiling characteristics of a typical gasoline. Weather-
cess unit material that is round-robin octane number (O.N.)
ing, however, can cause a change in octane number; thus the
calibrated using primary reference fuels, multiple engines, and
vapor pressure of the standard fuel may have to be lower than
so forth, for use in subsequent calibration of prototype fuels.
that of the product fuel. A Reid vapor pressure (RVP) less than
10 psi (68.9 kPa) is preferred but it shall not exceed 12 psi
3.2.11 system dead time—the period during analyzer opera-
(82.7 kPa) in any case.
tion when sample fuel quality measurement is not possible. It
6.2.3 Antiknock Compound such as organometallic lead or
includes prototype testing periods and the time required to
manganese shall be used in the standard fuel only if the product
attain knock testing unit/analyzer equilibrium on the sample
will contain them. The standard fuel shall contain the same
fuel.
compound used in the product and the concentrations in the
two fuels shall be similar.
4. Summary of Test Method
6.2.4 Octane Enhancers such as oxygenates shall be used
4.1 In this test method, the research or motor octane number
in the standard fuel if the product will contain them. The
of a gasoline product is determined by comparing its knock
standard fuel shall contain the same enhancer used in the
characteristics with those of a prototype of known research or
product and the concentrations in the two fuels shall be similar.
motor octane number of an automated repetitive cycle. The
6.2.5 Antioxidant protection is necessary to ensure storage
difference in knock characteristics may be measured as (1) the
stability for periods of up to one year of use.
difference in knock intensity at constant compression ratio, or
6.2.5.1 Antioxidants shall be added to the standard fuel
(2) the difference in compression ratio at constant knock
prior to any octane number calibration.
intensity. The test method assumes that the automatic analyzer
6.2.6 Metal Deactivator may be necessary and if added
system has been installed and adjusted according to the
shall be in accordance with supplier recommendations.
instructions of the manufacturer, whereby the knock intensity
6.2.7 Hydrocarbon Composition shall be similar to that of
or compression ratio differences are automatically utilized to
the related prototype fuel to be calibrated. Users are cautioned
produce a measure identified as DO.N. The research or motor
to investigate the effects of any large differences prior to
octane number of the product is based on the calibrated
application.
research or motor octane number of the prototype and the
6.2.8 Storage and Handling shall be under controlled
DO.N.
conditions to minimize the possibility of octane number change
4.2 The primary use of this test method is to evaluate a or contamination. Systems and procedures shall conform to the
steadily flowing sample which is continuously representative recommendations set forth in Annex A1 of this standard.
of a product stream that can originate from an in-line blender,
6.2.9 Octane Number Calibration shall be the average of
process unit, or transfer pipeline. In addition the method can be ratings on at least 16 different engines, preferably in as many
used to analyze individual samples on a repetitive basis. different laboratories as possible to minimize the potential for
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 2885 – 95 (1999)
individual location bias. These ratings shall be in complete 6.4 Check Fuels— Check Fuels are a pair of fuels for
system qualification check-out that are prepared, packaged,
accordance with the requirements of the research or motor
stored, and round-robin calibrated as if they were standard
methods for octane number measurement. Systems and proce-
fuels.
dures shall conform to the requirements set forth in Annex A2
6.4.1 The two check fuels shall have an expected difference
of this standard.
0.N. ranging from 0.2 to 1.0 octane number and be coded so the
6.3 Prototype Fuel is a secondary reference for establish-
difference in the calibrated average octane numbers (Fuel B
ing the octane number level that defines the product octane
from Fuel A) is a positive value.
number determined by automatic engine/analyzer systems. The
6.4.2 The fuel characteristics, including those for volatility,
characteristics, storage and handling procedures, calibration
antiknock compound, octane enhancers, and antioxidant pro-
and use of a prototype fuel shall conform to the following:
tection shall be similar for the two check fuels of a pair.
6.3.1 Octane Number shall be within 6 1.0 of the target
6.4.3 A standard fuel may be used interchangeably as a
octane number.
check fuel as long as it is paired with a second fuel that meets
6.3.2 Sensitivity, or the difference between research and
the requirements of a check fuel pair.
motor octane numbers, shall be no more than 6 1.0 octane
number different from those of the standard fuel with which it 7. Apparatus
is calibrated and the product fuels with which it will be used.
7.1 The knock testing units must be as specified in the
6.3.3 Volatility is not critical as long as the prototype fuel ASTM Research or Motor Methods.
7.2 The knock testing unit shall be supplemented by auto-
has the full boiling characteristics of a typical gasoline.
matic analyzer equipment to continuously measure the octane
Weathering, however, can cause a change in octane number;
difference between prototype fuel and product.
thus the vapor pressure of the prototype fuel may have to be
7.3 The knock testing unit and analyzer installation must
lower than that of the product fuel. A Reid vapor pressure
conform to the recommendations of the “Manual on Installa-
(RVP) less than 10 psi (68.9 kPa) is preferred but it shall not
tion of Refinery Instruments and Control Systems.”
exceed 12 psi (82.7 kPa) in any case.
7.4 The sample system must provide a continuously repre-
6.3.4 Antiknock Compound such as organometallic lead or
sentative product to the knock testing unit in accordance with
manganese shall be used in the prototype fuel only if the
the recommendations of the “Manual on Installation of Refin-
product will contain them. The prototype fuel shall contain the
ery Instruments and Control Systems.”
same compound used in the product and the concentrations in
7.4.1 Particulate contamination must be removed by a filter
the two fuels shall be similar.
of 100μ m or less.
6.3.5 Octane Enhancers such as oxygenates shall be used
7.4.2 Entrained water must not be present in the fuels at the
in the prototype fuel if the product will contain them. The
inlet to the automatic analyzer fuel conditioning equipment.
prototype fuel shall contain the same enhancer used in the
product and the concentrations in the two fuels shall be similar.
8. Operating Conditions
6.3.6 Antioxidant protection is necessary to ensure storage
8.1 The knock testing unit operating conditions must be
stability for periods of up to one year of use.
those specified in the research or motor methods.
6.3.6.1 Antioxidants shall be added to
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