Then the intake valve closes, and an exhaust valve opens.

然后进气阀关闭，打开 排气阀。

Then, an intake valve opens, allowing the steam into the engine.

然后，进气阀打开，让 蒸汽进入发动机。

Some of the blaze powder had fused to the sides of the intake valve, but it didn't seem completely clogged.

一些烈焰粉已经融合到进气阀的两侧，但似乎并没有完全堵塞。

Then, an intake valve opens, allowing the steam into the engine. The steam expands and moves a piston outward – that’s the work done by the engine.

然后，进气阀打开，让蒸汽进入发动机。蒸汽膨胀并向外移动活塞——这就是发动机所做的功。

This is even more likely to happen if the intake valve is only partially open, because there’s less room for the steam to enter and the water to escape at the same time.

如果进气阀仅部分打开， 则更有可能发生这种情况，因为蒸汽进入和水同时逸出的空间较小。