单项选择题
A.double-acting engine
B.opposed pistons engine
C.single-acting engine
D.horizontal acting engine
单项选择题 An increased pressure differential between the inlet and outlet of a strainer usually indicates the strainer is （）
单项选择题 Which of the following problems can cause fluctuating pressures in the closed cooling system of a main propulsion diesel engine?（）
单项选择题 If fuel injection to a four-stroke/cycle diesel engine begins earlier than designed, ignition may be delayed because the （）.