单项选择题
The diesel engine valve subjected to most severe conditions of service is the （）.
A.cylinder exhaust valve B.air starting valve C.air inlet valve D.cylinder relief valve
单项选择题 A piston in a four-stroke/cycle diesel engine makes four strokes during each （）.
单项选择题 The effective stroke of a constant-stroke, individual, fuel injection pump is varied by the （）.
单项选择题 The ability of a fuel particle to travel into the combustion chamber before burning is called （）.
