the position of a crank when it is in line with the connecting rod and not exerting torque
例句
用作名词 (n.)
The spark is therefore timed to occur before the piston reaches top dead center, otherwise maximum pressure would not be reached in time. 因而，在活塞到达上死点前，火花便会发生，否则就不可能适时达到最高的压力。
美
