单项选择题 What occurs in the combustion space of a diesel engine cylinder shortly after ignition and before the piston reaches TDC?（）

单项选择题 The power output of a turbocharged diesel engine will drop if the cooling water flow through the after-cooler is interrupted because the （）.

单项选择题 The diameter of a piston is usually less at the crown than at the skirt, in order to （）.