A six-cylinder regular fuel automotive engine was operated on both LP-gas and gasoline. Power, economy, air-fuel ratio control, spark advance characteristics, and exhaust hydrocarbon and carbon monoxide levels were obtained with both fuels over a wide range of steady-state and cyclic operating conditions. Significant improvements in economy and air pollution emissions occurred with LP-gas compared to gasoline at virtually all operating conditions. A system was developed to use the heat of vaporization of LP-gas to eliminate wide open throttle power loss. Unusually low levels of exhaust hydrocarbons and carbon monoxide were obtained by the use of a nonstandard LP-gas idle setting.
