idling reaction

例句：

1. 1. The car's engine is idling at 30 mph.
   汽车的引擎以每小时30英里的速度怠速运行。
2. 2.The idling reaction of the engine was causing a lot of noise.
   发动机的怠速反应引起了很多噪音。
3. 3. During the idling reaction, the fuel mixture in the engine is not fully ignited.
   在怠速反应期间，发动机内的燃料混合物并未完全点燃。