单项选择题
A.the indicating cock B.the starting valve C.air inlet valve D.the exhaust valve
In an ordinary four-stroke engine the exhaust valves op...
单项选择题In an ordinary four-stroke engine the exhaust valves open （）
A.after TDC B.before TDC C.after BDC D.before BDC
In an ordinary diesel engine the fuel injection begins ...
单项选择题In an ordinary diesel engine the fuel injection begins （）
In an oil cooler circulated by sea water, the oil is at...
单项选择题In an oil cooler circulated by sea water, the oil is at a larger pressure, the result being that any leak in the cooler will mean a loss of （）.
A.oil B.sea water C.refrigerant D.fresh water
