Самое начало:
(извините, в некоторых местах плохо распознано, обратите, пожалуйста, внимание на пункт 4.2 - это оно)
Standard Test Method for
Research Octane Number of Spark-Ignition Engine Fuel1
This standard is issued under the fixed designation D 2699: 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 reapprovai. A superscript epsilon (e) indicates an editorial change since the last revision or reapprovai.
This standard has been approved for use by agencies of ihe Department of Defense.1. Scope*
!.l This laboratory tesi method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N.. except that this test
- method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable com¬pression ratio, carbureted, CFR engine run in accordance with
"a defined set of operating conditions. The O.N. scale is defined
J by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends.
.The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.
-' 1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to
"420 Research O.N. Typical commercial fuels produced for
jispark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream
. materials can produce ratings at various levels throughout the Research O.N. range.
1.3 The values of operating conditions are slated in SI units
and are considered standard. The values in parentheses are the
' historical inch-pound 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 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 applica¬bility of regulatory limitations prior to use. For specific hazard statements, see Section 8, 13.4.1, A2.2.3.1, A2.2.3.3 (6) and (9), X4.3.4.1. X4.3.9.3, X4.3.1I.4, and X4.5.I.8.
2. Referenced Documents
2.1 ASTM Standards: 3
D 1193 Specification for Reagent Water
D 1744 Test Method for Determination of Water in Liquid
Petroleum Products by Karl Fischer Reagent4
D 2268 Test Method for Analysis of High-Purity n-Heptanc
and isoooctane by Capillary Gas Chromatography
D 2360 Test Method for Trace Impurities in Monocyclic
Aromatic Hydrocarbons by Gas Chromatography
D 2700 Test Method for Motor Octane Number of Spark-Ignition Engine Fuel D 2885 Test Method for Determination of Octane Number
of Spark-Ignition Engine Fuels by On-Line Direct Com¬parison Technique
D 3703 Test Method for Peroxide Number of Aviation
Turbine Fuels
D 4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
D4175 Terminology Relating to Petroleum, Petroleum
Products, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products D 4814 Specification for Automotive Spark-Ignition Engine Fuel
D 5842 Practice for Sampling and Handling of Fuels for Volatility Measurement
E 344 Terminology Relating to Thermometry and Hydrometry
E456 Terminology Relating to Quality and Statistics
E 542 Practice for Calibration of Laboratory Volumetric Apparatus
2.2 ANSI Standard:
C-39.1 Requirements for Electrical Analog Indicating In¬struments
2.3 Energy Institute Standard?
IP 224/02 Determination of Low Lead Content of Light Petroleum Distillates by Dithizonc Extraction and Colo-rimelric Method
3. Terminology
3.1 Definitions:
E 456
test method.
3.1.1 accepted reference value, n—a value that serves as an
agreed-upon reference for comparison, and which is derived
as: (/) a theoretical or established value, based on scientific
principles, (2) an assigned or certified value, based on experi¬
mental work of some national or international organization, or
(3) a consensus or certified value, based on collaborative
experimental work under the auspices of a scientific or
engineering group.
3.1.1.1 Discussion—In the context of this accepted reference value is understood to apply to the Research octane number of specific reference materials determined empirically under reproducibility conditions by the National Exchange Group or another recognized exchange testing orga¬nization.
3.1.2 Check Fuel, n—for quality- control testing, a spark-ignition engine fuels of selected characteristics having an octane number accepted reference value (O.N.ARV) determined by round-robin testing under reproducibility conditions.
3.1.3 cylinder height, n—for the CFR engine, the relative vertical position of the engine cylinder with respect to the piston at top dead center (tdc) or the lop machined surface of the crankcase. 3.1.3.1 dial indicator reading, n—for the CFR engine, a numerical indication of cylinder height, in thousandths of an inch, indexed to a basic setting at a prescribed compression pressure when the engine is motored.
3.1.3.2 digital counter reading, n—for the CFR engine, a numerical indication of cylinder height, indexed to a basic setting a! a prescribed compression pressure when the engine is motored. 3.1.4 detonation meter, n—-for knock testing, the signal conditioning instrumentation that accepts the electrical signal from the detonation pickup and provides an output signal for display.
3.1.5 detonation pickup, n—for knock testing, a magnetostrictive-type transducer that threads into the engine cylinder and is exposed to combustion chamber pressure to provide an electrical signal that is proportional to the rate-of-change of cylinder pressure.
3.1.6 dynamic fuel level, n—for knock testing, test proce¬dure in which the fuel-air ratio for maximum knock intensity for sample and reference fuels is determined using the Tallin» level technique that changes carburetor fuel level from a high or rich mixture condition to a low or lean mixture condition "at a constant rate, causing knock intensity to rise to a maximum and then decrease, thus permitting observation of the maxi¬mum knockmeter reading.
3.1.7 equilibrium fuel level, n—for knock testing, test pro¬cedure in which the fuel-air ratio for maximum knock intensity for sample and reference fuels is determined by making incremental step changes in carburetor fuel level, observing the equilibrium knock intensity for each step, and selecting the level that produces the highest knock intensity reading.
3.1.8 firing, n—-for the CFR engine, operation of the CFR engine with fuel and ignition.
3.1.9 fuel-air ratio for maximum knock intensity, n—for knock testing, that proportion of fuel to air that produces the highest knock intensity for each fuel in the knock testing unit. provided this occurs within specified carburetor fuel level limits. 3.1.10 guide tables, n—for knock testing, the specific rela¬tionship between cylinder height (compression ratio) and octane number at standard knock intensity for specific primary reference fuel blends tested at standard or other specified barometric pressure.
3.1.11 knock, n—in a spark-ignition engine, abnormal com¬bustion, often producing audible sound, caused by autoignition of the air/fuel mixture. I) 4175
3.1.12 knock intensity, n—-for knock testing, a measure of the level of knock.
3.1.13 knockmeter, n—for knock testing, the 0 to 100 division indicating meter that displays the knock intensity signal from the detonation meter.
3.1.14 motoring, n—-for the CFR engine, operation of the CFR engine without fuel and with the ignition shut off.
3.1.15 octane number, n—for spark-ignition engine fuel. any one of several numerical indicators of resistance to knock obtained by comparison with reference fuels in standardized engine or vehicle tests. D 4175
3.1.15.1 research octane number, n—for spark-ignition en¬gine fuel, the numerical rating of knock resistance obtained by comparison of its knock intensity with that of primary refer¬ence fuel blends when both arc tested in a standardized CFR engine operating under the conditions specified in this test method.
3.1.16 oxygenate, n—an oxygen-containing organic com¬pound. which may be used as a fuel or fuel supplement, lor example, various alcohols and ethers. D 417?
3.1.17 primary reference fuels, n—for knock testing, isooc-tane. n-heptane, volumetrically proportioned mixtures ofisooc-tane with n-heptane, or blends of tetraethyllead in /jooctane that define the octane number scale. 3.1.17.1 primary reference fuel blends below 100 octane. n—the volume % of Kooctane in a blend with л-hepiane that defines the octane number of the blend, /sooctane being assigned as 100 and n-heptane as 0 octane number.
3.1.17.2 primary reference fuel blends above 100 octane. n—the millilitres per U.S. gallon of tetraethyllead in isooctane (.......)
4. Summary of Test Method |r 4.1 The Research O.N. of a spark-ignition engine fuel is determined using a standard test engine and operating condi¬tions lo compare its knock characteristic with those of PRF "isblends of known O.N. Compression ratio and fuel-air ratio are jBadjusted to produce standard K.I. for the sample fuel, as measured by a specific electronic detonation meter instrument
ystem. A standard K.I. guide table relates engine C.R. to O.N. 7level for this specific method. The fuel-air ratio for the sample luel and each of the primary reference fuel blends is adjusted to maximize K.I. for each fuel. "I 4.1.1 The fuel-air ratio for maximum K.I. may be obtained by making incremental step changes in mixture strengih, observing the equilibrium K.I. value for each step, and then _ selecting the condition thai maximizes the reading or (2) by picking the maximum K.I. as the mixture strengih is changed from either rich-to-lean or lean-to-rich at a constant rale.
4.2 Bracketing Procedures—The engine is calibrated to operate at standard K.l. in accordance wiih the guide table. The fuel-air ratio of Ihe sample fuel is adjusted to maximize the K.I., and then the cylinder height is adjusted so that standard K.l. is achieved. Without changing cylinder height, two PRF blends are selected such that, at their fuel-air ratio for maximum K.I, one knocks harder (higher K.l.) and the other sofler (lower K.I.) than ihe sample fuel. A second set of K.I. measurements for sample fuel and PRF blends is required, and the sample fuel octane number is calculated by interpolation in proportion to the differences in average K.I. readings. A final condition requires thai the cylinder height used shall be within prescribed limits around the guide table value for the calculated O.N. Bracketing procedure ratings may be determined using either the equilibrium fuel level or dynamic fuel level fuel-air ratio approach.
4.3 C.R. Procedure—A calibration is performed to establish standard K.I. using the cylinder heighi specified by ihe guide table for the O.N. of the selected PRF. The fuel-air ratio of the sample fuel is adjusted to maximize the K.I. under equilibrium conditions; the cylinder height is adjusted so that standard K.I. is achieved. The calibration is reconfirmed and the sample fuel raling is repealed to establish the proper conditions a second time. The average cylinder height reading for the sample fuel, compensated for barometric pressure, is converted directly to O.N., using the guide table. A final condition for the raling requires that the sample fuel O.N. be within prescribed limits around that of the O.N. of the single PRF blend used to calibrate the engine to the guide (able standard K.I. condition.
5. Significance and Use
5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild con¬ditions of operation.
5.2 Research O.N. is used by engine manufacturers, petro¬leum 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 auto¬
motive antiknock performance are based on the general equa¬
tion:
Road O.N. = Ц-, X Research O.N.) + (k2 X Motor O.N.) + k3 (1)
Values of kt, k2. and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.
5.2.2 Research O.N., in conjunction with Motor O.N..
defines ihe antiknock index of automotive spark-ignition en¬
gine fuels, in accordance with Specification D4814. The
antiknock index of a fuel approximaies the Road oclane ratings
for many vehicles, is posted on retail dispensing pumps in the
U.S.. and is referred to in vehicle manuals.
Antiknock index = 0.5 Research O.N. + 0.5 Motor O.N. + 0 (2)
This is more commonly presented as:
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