To date.SI engines for stationary and vehicular applciations are not only faced with stringent emission legislation but also with increasing requirements to powr density while reducing operating and investiment cost.With increassing power density (bmep) and air excess (efficiency,) the demands to ignition energy are also growing.Hence,in SI gas engines,the provision of sufficient ignition kenergy for reliable inflammation fo the gas/air-mixture represents a crucial parameter.the achievealbe power output and efficency thus is kprimarily limited by the spark plug.Igniting the mixture by a small amount of diesel pilot may solve this problem.However,this requres the applciation of latest injection systems featureing flexible injection rate shapng and igh reproducibility even with small amounts of pilot ,in orde rto cope with stringent NO_x emission limits.The paper describes test results with a piezoelectrically controlled common rail injection system.
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