Correlation Concept Between Mixture Formation and Ignition Applied to a GDI High Speed Engine

The paper presents a GDI concept applied to a fourstroke four-valve single cylinder engine in base of the original “crevice-like” combustion chamber of the basic engine with external mixture formation. For such application both, an adapted shape of injection rate as well as a good correlation of location and timing between injection and spark is requested. The shape of injection rate is adapted in base of a pressure pulse injection system. The paper presents the special features of the system conceived for this aim, as well as the results for different locations of injector and spark plug. The best results in terms of bmep, bsfc and pollutant emissions are obtained with a twin spark configuration. The mixture formation and combustion particularities of this concept are analyzed going from the experimental results at the engine test bench for full and part-load in condition of widely unthrottled operation. Complete paper available under: http://www.sae.org/servlets/productDetail?PROD_TYP= PAPER&PROD_CD=2002-01-0833