Some problems of combustion system operation with semi-open combustion chamber for spark ignition engine

The some problems concern of the new combustion system operation with semi open combustion chamber, which can be used in spark ignitions internal combustion engines are presented in this paper. These considerations are based on the visualization research results, with using rapid compression machine (RCM). In this researched combustion system the original combustion chamber was divided by partition in prechamber and main combustion chamber. This division of the original combustion chamber exists only when the piston is close to TDC, for the rest of the cycle the chambers arefully open. Ignition is initiated in the prechamber using electric spark plug, but the mixture in main combustion chamber is ignited by the stream of the burned gases injected from prechamber through the orifice in partition, if the ignition advance angle is correct. If the ignition advance angle is incorrect the mixture from prechamber will be outflowing through the orifice in partition and through the slot which is created between the partition and piston crowns. This last stream is swirled on the partition edge, what causes decrease of the stream speed outflowed from the orifice in partition to main combustion chamber. If the ignition advance angle is too big, then a peak pressure and compression work is very big because the burned gases are compressed instead of the fresh air/fuel mixture. This causes that the effective work is small and combustion efficiency is small.