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. SAE J1498_201709 provides information on the standardized procedures for determining the heat of combustion of fuels that may be used for automotive engines.