This paper describes the results of a research undertaken at Ecole Polytechnique in order to improve the combustion characteristics of natural gas used as an alternate fuel in a spark ignition engine originally designed for gasoline.
Due to the physical characteristics of NG, users may experience a power loss ranging from 10 to 20% of original power. Since, for some applications, this loss is not acceptable, means to enhance combustion must be found. In this search for more power, various possibilities may be explored but, in this particular research, mixtures of NG and gasoline were supplied to a single cylinder engine in order to improve its performance: since the flame speed is faster in gasoline - air mixtures than in methane - air mixtures it was postulated that methane -gasoline - air mixtures might have better combustion characteristics.
Thus, a systematic study of NG - gasoline mixtures was performed and is described here; first the experimental procedure is reviewed and then the results of the tests are discussed.
Benefits deriving from gasoline introduction are varying with substitution rates but both horsepower and efficiency are increased by the addition of gasoline.