Reference Fuel

reference fuel

[′ref·rəns ‚fyül]
One of the standardized laboratory engine fuels, blends of which are used to determine the octane numbers of motor gasoline and the cetane numbers of diesel fuels.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Reference Fuel


a liquid hydrocarbon or blend of liquid hydrocarbons used to evaluate the performance characteristics of fuels. Reference fuels make it possible to determine the antiknock rating (octane number and gasoline performance rating) and the spontaneous combustion rating (cetane number) of fuels for piston engines as well as the flame intensity rating (luminometer number) for gas turbine fuels. They may be classified as primary and secondary types. The former are blends of isooctane (octane number = 100) and n-heptane (octane number = 0), of cetane (cetane number = 100) and α-methylnaphthalene (cetane number = 0), and of isooctane (luminometer number = 100) and tetrahydronaphthalene (luminometer number = 0).

Because of the high cost of primary reference fuels, cheaper secondary reference fuels are often used instead and calibrated against the primary fuels. A secondary reference fuel used to determine octane numbers may be a blend of technical-grade isooctane (octane number = 98–99) and straight-run gasoline (octane number not less than 68) or white spirits (octane number = 17–27). The secondary reference fuel used to determine cetane numbers is a blend of straight-run diesel fuel from a paraffinbase petroleum (cetane number not less than 55) and a highly aromatic diesel fraction of pyrolysis products (cetane number not more than 20). Gasoline performance ratings are determined from comparison with a reference fuel consisting of either pure technical-grade isooctane or a blend of same with tetraethyl lead (0.3–0.8 g per kg of isooctane) or with n-heptane (5–10 percent by volume).

In some cases evaluations are made of such fuel operating characteristics as antiwear properties and the tendency to form carbon deposits. For such purposes, the reference fuel used (in addition to those already described) may be n-pentadecane or a blend of 85 percent (by weight) cetane and 15 percent α-methylnaphthalene.

Reference fuels are also used in comparative bench tests of engines. The petroleum fractions used for such purposes conform to special standards that define density range, viscosity, boiling point, vapor pressure, calorific value, and sulfur content.


Zabrianskii, E. I., and A. P. Zarubin. Detonatsionnaia stoikost’ i vos-plameniaemost’ motornykh topliv, 3rd ed. Moscow, 1974.
Piskunov, V. A., and V. N. Zrelov. Ispytaniia topliv dlia aviatsion-nykh reaktivnykh dvigatelei. Moscow, 1974.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The CPPA had sought the permission for increasing of 0.0669 per unit from power consumers and pleaded that it had charged reference fuel price of Rs5.1130 per unit from consumers in June, while the cost was Rs5.180 per unit.
It told the regulator that it had charged a reference fuel price of Rs5.1130 per unit in June while the cost came in at Rs5.180 per unit.
The CPPA-G maintained the cost of per unit remained at Rs 5.519/kWh against the reference fuel charges of Rs 5.235 kWh per unit fixed for April.
It told the regulator that it had charged reference fuel price of Rs5.2359 per unit from consumers in April, while the actual cost turned out to be Rs5.8055 per unit.
The reference fuel cost for the month of February was at Rs3.97 per unit.
According to the regulator, reference fuel costs in February remained 3.97 rupees per unit.
According to details, the Central Power Purchasing Agency (CPPA) has submitted an application with NEPRA, seeking Rs1.9382/kWh power tariff hike over the reference fuel charges, i-e.
The reference fuel cost was set at Rs5.04 per unit but the actual price came in at Rs4.71 for November, showing a reduction of Rs0.33 per unit.
In a petition submitted to National Electric Power Regulatory Authority (NEPRA), the CPPA-G maintained the cost of per unit remained at Rs 5.60/kWh against the reference fuel charges of Rs 4.98/ kWh per unit fixed.
NEPRA was briefed during the hearing that the cost of reference fuel remained Rs 5.29 in May while electricity was produced at the cost of Rs 12.

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