The lower section of a piston is called the （）.

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 （）.

A.crankshaft revolution
B.mechanical cycle of operation
C.period of two combustion cycles
D.cycle of two events

单项选择题The effective stroke of a constant-stroke, individual, fuel injection pump is varied by the （）.

A.control rack
B.delivery valve
C.governor speed
D.plunger crossbar

单项选择题The ability of a fuel particle to travel into the combustion chamber before burning is called （）.

A.penetration
B.permanence
C.turbulence
D.atomization

单项选择题Proper atomization of fuel in diesel engine combustion chambers will （）.

A.affect the injection pressure
B.improve combustion
C.reduce compression pressure
D.decrease power output