Influence of compression ratio on combustion, turbulence, swirls into model combustion chamber of SI engines

The results of the visualization researches, with the pressure measurement results are presented in the paper. Researches deal with the combustion system with semi-open combustion chamber for spark ignition engines. This system was elaborated in Aircraft Engine Department of Heat Engineering Institute of Warsaw University of Technology. During researches the influence of CR on a flame front propagation and turbulences into combustion chamber, when CR and ignition advance are varied, was determined. The model combustion chamber was made with the constant volumes ratio (the prechamber volume to the prechamber plus main combustion chamber volumes) of 28%. The CR were varied: 6:1, 8:1, 10:1 and 12:1, by changing of combustion chamber length and establish high. The researches were performed using rapid compression machine (RCM). The combustion sequences were recorded using high-speed digital camera with speed of 5000 frames per second. Simultaneously with combustion sequences recording, the high-speed pressure courses were registered. The research results show that the growth of compression ratio causes an improvement of combustion system performances; an increase of maximum cycle pressure and useful work field. The improvement of the performances is caused mainly by shortening of the combustion time and intensification of the turbulences and approaching of supposed combustion course.