Effect of Ignition Timing and Excess Air Ratio on Combustion Characteristic of Linear Engine

Abstract

Based on the linear engine prototype designed by the studying team, the combustion characteristic of the linear engine in certain revolution is investigated experimentally. The effect of ignition timing and excess air ratio on combustion characteristic of the linear engine is studied based on cycle-by-cycle control technique. The result shows that the ignition timing has effect on the combustion characteristic of linear engines in certain revolution. Advancing the ignition timing from 1.0mm BTDC (before the top dead center) to 3.0mm BTDC, the peak cylinder pressure increases, the interval between peak cylinder pressure timing and the top dead center reduces, the IMEP (indicated mean effective pressure) is down, the instantaneous heat release rises and the total heat release decreases. The excess air ratio has apparently effect on combustion characteristic of linear engines in certain revolution. Reducing the excess air ratio from 1.45 to 1.35, the peak cylinder pressure increases, the peak cylinder pressure timing is closer to the top dead center, the instantaneous heat release and the total heat release are larger.