Metrological aspects of development and usage of indirect octane number definition methods

Lev V. Machulin Gazprom VNIIGAZ Ukhta, Russian Federation
Such methods depends ona measuringThe goal of this work is to study methods and means of defining automobile gasoline most important operational characteristic - octane number.
Materials and methods
Test single-cylinder engines UIT-85, infrared octane analyzer ZX-101C, gas chromatographs type 3700 and Tsvet-800, densitometers ANT-2 for gasoline, refractometer IRF-454B2M, stand- ard fuels (isooctane and n-heptane), natural gas-condensate distillates, gasoline and catalyzate of molecular sieve reforming; methods of gas chromatography, infrared spectrometry, refractometry and densitometry.
Some metrological properties of different in direct methods for knock resistan ceestimation investigated. Several consistent patterns witch establish a scope of such techniquesobtained.
1. Only standard engine knocking testgives a true value of octane number, but octane number is not an object of direct measurement.2. Trueness of indirect method mainly depends on type and adequacy of mathematical model, repeatability ofinstrument.3. There is no unique dependence between octane number and physical parameters of commercial automobile gasoline andoctane number, such connection exists only for low-aromatics natural distillates.4. NIR-spectroscopic and chromatodensitometry methods have the best prospects for indirect determination of octane number.
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gasoline octane number indirect methods gas chromatography reproducibility repeatability