Search Results

An experimental study was made to investigate the effect of combustion chamber configuration, top clearance, nominal swirl ratio, and spark plug position on in-cylinder combustion in a spark-ignited natural gas engine, which is converted from a direct injection diesel engine. Flame propagation in a single-cylinder visualization engine was measured from the cylinder axis direction by the high speed schlieren method, over the wide range of combustion chamber configuration, top clearance, nominal swirl ratio, and spark plug position. The results showed that flame does not propagate concentrically to the spark plug, but is shifted by swirl, which is the main flow in this engine. Smaller piston cavity diameter led to more rapid flame propagation, resulting in larger heat release rate and larger cylinder pressure. Piston cavity diameter does not affect the initial combustion until TDC.