弹簧处于“压缩”状态时，意味着弹簧试图伸展，气门受弹簧作用而处于关闭状况。
The spring is under compression, which means that it tries to expand and therefore spring-loads the valve in the closed position.
利用气缸压力对气门间隙和点火提前角的工作状态进行识别，从而达到对发动机的动力性能进行监测的目的。
The operating conditions of valve clearance and ignition timing are identified via cylinder pressure so that monitoring of the dynamic performance...
气门杆上的弹簧使气门保持在气门座上(关闭状态)。弹簧的下端抵在气缸盖上。
A spring on the valve stem tends to hold the valve on its seat (closed). The lower end of the spring rests against the cylinder head.
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