Study on the Shutdown State of CNG Engine

We studied the shutdown state of natural gas engine on a modified GW4B13 direct injection engine. The result shows that when the engine is cold, high speed hold a dominant factor, causing the engine spends longer time shutting down than the time under the hot engine situation; stop position of the engine is normal distribution, and the majority of the stop position is located before the top dead center between 70° to 90°; when the stop position before the top dead center 90° and 120 ° , the engine spends shortest time, less than 0.3s, reaching the target speed, i.e. the idle speed 400rpm.