The function of diesel engine piston compression rings is to （）.

单项选择题A diesel engine piston ring face is in direct contact with the （）.

A.top of the ring groove
B.cylinder liner oil film
C.bottom of the ring groove
D.back of the ring groove

单项选择题If the water level dropped rapidly in the expansion tank of a closed diesel engine cooling water system, you should suspect a （）.

A.loss of suction in the circulating pump
B.leak in the primary cooling system
C.broken raw water pump shaft
D.burned or cracked piston in one cylinder

单项选择题In a simple mechanical governor, the （）.

A.centrifugal force rotates the ball-head
B.flyweight centrifugal force is balanced by spring force
C.flyweight centrifugal force is balanced by hydraulic pressure
D.speeder spring alone actuates the fuel control rod

单项选择题The ability of the governor to prevent fluctuations in engine speed is termed （）.

A.sensitivity
B.stability
C.promptness
D.speed droop

单项选择题What is the function of the thrust bearing?（）

A.Prevents lateral movement of the slow speed gear
B.Transmits propeller thrust to the hull
C.Keeps spring bearings in line
D.Prevents main reduction gear axial movement