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The future development of two-stroke engines will be conditioned by the drastic reduction of pollutant emission, especially of hydrocarbon. This goal is not achievable only by scavenging improvement, rather a new quality of mixture formation using direct injection is imposed. However, the internal mixture formation in a large range of speed and load, considering the scavenge flow particularities of two-stroke engines as well, appears as an extremely complex process. Thereby a numerical simulation is in this case very effective for the adaptation of a direct injection method at the engine. The paper presents a concept for modeling and optimization of the mixture formation process within a high-speed two-stroke engine with liquid fuel injection system. The injection system generates a pressure pulse which is not dependent on the engine speed.

The paper presents a concept for modeling and optimization of the mixture formation process during gasoline direct injection, using a high-pressure single fluid injection system which allows the modulation of the injection rate independently on the engine speed. Going from this favorable premise for the adaptation of the mixture formation to various load and speed conditions, the aim of modeling is to find the optimum combination between the adaptable elements as follows: form of the fuel pressure wave, injection timing, spray form, injector location, form of the combustion chamber. Moreover, the interaction between fuel and air flow within the cylinder during the mixture formation is considered as a determining factor for the combustion process, and forms thereby an important part of the modeling.