D2699 1.1 This
laboratory test 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. The sample fuel is tested
using a standardized single cylinder, four-stroke cycle, variable
compression ratio, carbureted, CFR engine run in accordance with a
defined set of operating conditions. The O.N. scale is defined 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 120 Research O.N. Typical commercial
fuels produced for spark-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.
Standard Test Methods
for
Research Octane Number of Spark-Ignition Engine Fuel
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