单项选择题
In a four-stroke cycle diesel engine the intake valves open （）
A.before TDC and close after BDC B.after TDC and close after BDC C.before TDC and close before BDC D.after TDC and close before BDC
单项选择题 Diesel engine air start system check valves are opened by （）
单项选择题 For a diesel engine, individual cylinder performance is commonly determined by exhaust gas（）
单项选择题 Low compression pressure in a diesel engine may be the result of （）
