Experimental study on the effects of injection pressure on the combustion in a SI aviation piston engine fueled with kerosene

Abstract

Kerosene becomes an alternative to gasoline in aviation piston engines for its safety and easy replenishment on some special occasions. However, the low octane number of kerosene tends to cause the knock of SI engine, as a result, most of the current SI kerosene engines run in an operation mode of two-stroke, which has the disadvantage of a low compression ratio and high fuel consumption. This study conducted a series of experiments on a two-stroke SI kerosene engine equipped with an air-assisted direct injection system to improve engine performance and fuel economy by increasing injection pressure and combining it with control strategy optimization. First, the effects of injection pressure on the combustion of kerosene engines were studied, including cylinder pressure, combustion rate, and the stability of combustion. The results show that increasing the injection pressure shortens the ignition delay, accelerates the combustion, and substantially improves the combustion stability. Then, the effects of increasing the injection pressure on the control strategies of injection advance angle, ignition advance angle, and fuel injection duration were investigated. Ultimately, based on the investigation of the effects of injection pressure on the control strategies, two optimizations of control strategies were obtained to reduce fuel consumption and increase power, respectively, with the former reducing fuel consumption by 14.9% and the latter increasing power by 6%.