问题描述：
[单选]
The crankcases of many diesel engines are kept under a slight vacuum to（）
A．improve fuel economy
B．increase the air charge velocity
C．reduce the risk of explosion
D．all of the above
参考答案：查看无
答案解析：无
☆收藏
答案解析：无
☆收藏
上一篇：The rate of cylinder lubricating oil metered to each cylinder of a large low-speed main propulsion diesel engine is（）
下一篇：Which of the following conditions could cause the feed pump for an auxiliary boiler to lose suction？
- 我要回答: 网友(216.73.216.96)
- 热门题目: 1.造成增压器涡轮壳体腐蚀的原因 2.怎样对连杆螺栓进行检测？ 3.对偶件的磨损怎样检验？