Cold start characteristics at low temperatures based on the first firing cycle in an LPG engine

摘要

The cold start characteristics of the first firing cycle were investigated experimentally for a small electronic control fuel injection spark ignition engine fuelled with liquefied petroleum gas. The instantaneous crankshaft rotational speed, cylinder pressure and hydrocarbon emission in the first firing cycle were measured for different excess air coefficients, battery voltage, ignition advance angle and environmental temperatures ranging from -9℃ to +4℃. The results show that combustion reliability, crankshaft speed and HC emission are significantly affected by the excess air coefficient during cold start. The environmental temperature has a significant influence on HC emission but not for crankshaft speed. The ignition advance angle affects crankshaft speed, while it only has a mild impact on HC emission. The battery voltage significantly affects crankshaft speed and HC emission. The parameter behavior representing successful cold start was determined along with the optimal value of the excess air coefficient and ignition advance angle.