Study on Cycle-by-Cycle Variation of Ethanol Homogeneous Charge Compression Ignition Combustion

摘要

The effects of cycle-by-cycle variation on the ethanol Homogeneous Charge Compression Ignition have been investigated in a single cylinder engine modified from a CA6110 diesel engine. The results show that as the air/fuel ratio increases, the cycle-by-cycle variations of maximum pressure and mean indicated pressure increase, the variation of the start of combustion (SOC) increases, and the variation of combustion duration period increases. As the intake charge temperature rises, the maximum pressure increases, but the mean indicated pressure increases firstly and then drops, the standard deviation of the SOC increases, and combustion duration period shortens, its variation decreases. Proper amount EGR inducted can dramatically improve combustion rate and decrease the pressure rise ratio, but too much amount of EGR would result in unstable even intermittent combustion.