This SAE Recommended Practice summarizes the composition of modern automotive gasolines, the significance of their physical and chemical characteristics, and the pertinent test methods for defining or evaluating these properties.

This SAE Information Report provides information on certain fuels that are being used or have been suggested as alternatives to motor gasoline (SAE J312) or automotive diesel fuel (SAE J313) for use in spark-ignition or compression-ignition engines. Some of these fuels are derived from petroleum while others are from non petroleum sources.

The heating value or heat of combustion is a measure of the energy available from the fuel. The fraction or percentage of the heat of combustion that is converted to useful work is a measure of the thermal efficiency of an engine. Thus, a knowledge of the heat of combustion of the fuel is basic to the engineering of automotive engines. This SAE Information Report provides information on the standardized procedures for determining the heat of combustion of fuels that may be used for automotive engines. The changes to SAE J1498 include: SAE Publications - Added SAE Paper 2010-01-1517 Other Publications and Sections 5, 9, and 10 - Updated ASTM alphanumeric designations and titles. Section 10 - Added discussion of a method to calculate net heating value for gasoline-ethanol blends using ASTM D3338.

Automotive and locomotive diesel fuels, in general, are derived from petroleum refinery products which are commonly referred to as middle distillates. Middle distillates represent products which have a higher boiling range than gasoline and are obtained from fractional distillation of the crude oil or from streams from other refining processes. Finished diesel fuels represent blends of middle distillates and may contain other blending components of substantially non-petroleum origin, such as biodiesel fuel blend stock, and/or middle distillates from non-traditional refining processes, such as gas-to-liquid processes. The properties of commercial distillate diesel fuels depend on the refinery practices employed and the nature of the crude oils from which they are derived. Thus, they may differ both with and within the region in which they are manufactured. Such fuels generally boil, at atmospheric pressure, over a range between 130 °C and 400 °C (approximately 270 °F to 750 °F). Their makeup can represent various combinations of volatility, ignition quality, viscosity, sulfur level, density, and other characteristics. Additives may be used to impart specific properties to the finished…

Compressed Natural Gas (CNG) is a practical automotive fuel, with advantages and disadvantages when compared to gasoline. Large quantities of natural gas are available in North America. It has a higher octane number rating, produces low exhaust emissions, no evaporative emissions and can cost less on an equivalent energy basis than other fuels. Natural gas is normally compressed from 20 684 to 24 821 kPa (3000 to 3600 psig) to increase its energy density thereby reducing its on-board vehicle storage volume for a given range and payload. CNG can also be made from liquefied natural gas by elevating its pressure and vaporizing it to a gas. Once converted it is referred to LCNG. The properties of natural gas are influenced by: (1) source of supply i.e. field, composition or impurities; (2) the processing of natural gas by the production and transmission companies; (3) the regional gas supply, storage, and demand balancing done by distribution companies often in concert with pipeline companies to maintain uninterrupted service throughout the year, e.g., peak shaving with propane-air (see U.S.…

Compressed Natural Gas (CNG) is a practical automotive fuel, with advantages and disadvantages when compared to gasoline. Large quantities of natural gas are available in North America. It has a higher octane number rating, produces low exhaust emissions, no evaporative emissions and can cost less on an equivalent energy basis than other fuels. Natural gas is normally compressed from 20 684 to 24 821 kPa (3000 to 3600 psig) to increase its energy density thereby reducing its on-board vehicle storage volume for a given range and payload. CNG can also be made from liquefied natural gas by elevating its pressure and vaporizing it to a gas. Once converted it is referred to LCNG. The properties of natural gas are influenced by: (1) source of supply i.e. field, composition or impurities; (2) the processing of natural gas by the production and transmission companies; (3) the regional gas supply, storage, and demand balancing done by distribution companies often in concert with pipeline companies to maintain uninterrupted service throughout the year, e.g., peak shaving with propane-air (see U.S.…

The mass of air required to burn a unit mass of fuel with no excess of oxygen or fuel left over is known as the stoichiometric air-fuel ratio. This ratio varies appreciably over the wide range of fuels - gasolines, diesel fuels, and alternative fuels - that might be considered for use in automotive engines. Although performance of engines operating on different fuels may be compared at the same air-fuel ratio or same fuel-air ratio, it is more appropriate to compare operation at the same equivalence ratio, for which a knowledge of stoichiometric air-fuel ratio is a prerequisite. This SAE Recommended Practice summarizes the computation of stoichiometric air-fuel ratios from a knowledge of a composition of air and the elemental composition of the fuel without a need for any information on the molecular weight of the fuel.

The heating value or heat of combustion is a measure of the energy available from the fuel. The fraction or percentage of the heat of combustion that is converted to useful work is a measure of the thermal efficiency of an engine. Thus, a knowledge of the heat of combustion of the fuel is basic to the engineering of automotive engines. This SAE Information Report provides information on the standardized procedures for determining the heat of combustion of fuels that may be used for automotive engines. The changes to SAE J1498 include: SAE Publications - Added SAE Paper 2010-01-1517 Other Publications and Sections 5, 9, and 10 - Updated ASTM alphanumeric designations and titles. Section 10 - Added discussion of a method to calculate net heating value for gasoline-ethanol blends using ASTM D3338.

This SAE Recommended Practice summarizes the composition of modern automotive gasolines, the significance of their physical and chemical characteristics, and the pertinent test methods for defining or evaluating these properties.