The alarming rate at which the Earth's atmosphere is getting polluted, the increased impact of global warming on the weather conditions on Earth and the stringent anti-pollution laws imposed in certain countries are among the main reasons for the search for alternatives to gasoline. Liquefied Petroleum Gas (LPG) (mainly propane) is among the many alternatives proposed to replace gasoline in the short term due to its excellent characteristics as a fuel for spark ignition (Sl) engines. This paper presents a discussion on the parameters that affect the engine's heat losses mainly during power stroke, with suggestions to minimise it. The effect of the equivalence ratio, compression ratio, spark plug location, and combustion duration at different speeds on the heat losses has been studied. (C) 2002 Elsevier Science Ltd. All, rights reserved.