Abstract
To study knocking phenomenon in stratified mixture condition, n-heptane /air mixture was fed into rapid compression machine (RCM) in a given concentration gradient. The auto-ignition took place by rapidly compressed mixture and the pressure history inside cylinder was measured. To separate the low frequency component from high one, the pressure trace was processed numerically by low and high frequency filter, and the ignition delay, the pressure increasing rate, the maximum pressure fluctuation and knocking intensity factor were defined and used to examine the knocking phenomenon. To simulate the auto-ignition phenomenon in the RCM a reduced mechanism of n-heptane oxidization reaction was employed. Both the experimental and numerical simulation results have the same tendency in the ignition delay and the pressure increasing rate.
