In a diesel engine, there is no spark plug. Instead, diesel fuel is injected into the cylinder, and the heat and pressure of the compression stroke cause the fuel to ignite.
柴油发动机内没有火花塞，取而代之的是将柴油喷入发动机气缸，然后压缩冲程在高温高压下引起燃料点火。
2
However, a two-strokeengine USES more gasoline and burns lots of oil, so it is far more polluting.
二冲程发动机使用更多的汽油，燃烧更多的燃料，所以产生更多的污染。
3
What is the difference between a two-stroke and a four-strokeengine? Most chain saws and boat motors use two-stroke engines.