这里介紹的是利用蓄能器蓄能的一个例子,卽当煤車底門打开吋,将所产生的一部分势能轉換給蓄能器,然后利用此能关閉車門。車門落下的过程使車門开閉器內的油迅速地流入蓄能器。这种能量以后就足以用作关閉車門,因为在关閉时仅須克服它們的重力和鉸鏈的摩擦力卽可关閉。 Here is an example of accumulating energy using an accumulator. When the bottom door of the coal car is opened, some of the generated potential energy is transferred to the accumulator, which can then be used to close the door. The process of dropping the door causes the oil in the door shutter to flow rapidly into the accumulator. This energy is sufficient later to close the doors, since only the gravity and the friction of the hinges must be overcome when they are closed, so that they can close.