排气冲程：做功行程接近终了时，排气门开启，由于这时缸内压力高于大气压力，高温废气迅速排出气缸，这一阶段属于自由排气阶段，高温废气以当地音速通过排气门排出。
排气冲程随着活塞经过下止点并上行至上止点。
The exhaust stroke continues as the piston passes BDC and moves upward to past TDC.
这四招进气行程，紧缩行程，动力冲程和排气冲程。
These four strokes are intake stroke, compression stroke, power stroke and exhaust stroke.
进气冲程在活塞位与气缸顶部（进气门开启，排气门关闭）时开始，在活塞到达其行程的底部时结束。
The intake stroke starts with the pistonat the top of the cylinder (intake valve open and exhaust valve closed) and stops with the pistonat the bottom of its travel.
应用推荐