The influence of the fuel stratification on the IC engine working cycle with the compressed natural gas

The gaseous fuels are very convenient from the economic aspect as well as from the ecology aspect. Fuel stratification allows the engine work with the globally lean mixture and in this way increase the engine efficiency and reduces the pump losses. The separation of the engine working space, on the area where the mixture will be always rich, and on the area where the mixture will be always lean, allows the spark ignition engine work with the globally lean mixture. In the paper it was investigated, how the fuel stratification ratio influences on the combustion process of the compressed natural gas in the spark ignition engine. It was found that the stratification ratio has a great influence on the combustion process, as well as on the engine performances and the efficiency. Based on the research it was identified the optimal combustion process from the aspect of the performances and the efficiency.