Recent research on internal combustion spark ignited engines has focused more and more on charge control by means of direct injection.
Nevertheless most of the systems proposed so far do not seem to be suitable for small engines as they are high-cost.
A new direct injection system, based on the hydraulic phenomenon commonly known as “water hammer” has been recently proposed by the authors to be used for small two-stroke engines.
It constitutes a reliable means of achieving high injection pressures while maintaining the simple manufacturing and low-cost characteristics of this kind of engines. It is equipped with a low-pressure fuel pump and provides high injection pressure values thanks to the conversion of the kinetic energy of the fluid into a local pressure rise, which takes place when the fuel flow is suddenly halted by an automatic valve.
The first results from a simulation code which takes into account of cavitation and column separation phenomena typical of the system's behaviour are presented.
The influence of various parameters on system's performances is discussed.