The minimum speed an engine must attain before ignition can occur depends upon （）.

单项选择题For a given size engine, the two-stroke cycle diesel engine will deliver more power than a four-stroke cycle diesel engine because （）.

A.it has a longer power stroke
B.more air gets into the cylinder each stroke
C.it develops twice as many power strokes at the same speed
D.higher combustion pressure is developed

单项选择题Lube oil cannot be efficiently filtered if its （）.

A.viscosity is too low
B.temperature is too low
C.pump discharge pressure is higher than the systems pressure
D.pump capacity is greater than the systems needs

单项选择题In using reduction gears to obtain efficient propeller speeds, （）.

A.they must be located at the after end of the engine
B.they can only be used with one engine at a time
C.they eliminate the need for controllable pitch propellers
D.they are connected to the engine with a flexible coupling

单项选择题Combustion knock occurring in a diesel engine can be caused by （）.

A.excessive fuel penetration
B.prolonged injection lag
C.reduced ignition lag
D.prolonged ignition lag

单项选择题A thrust bearing is used with a propulsion diesel engine to （）.

A.control axial movement of the crankshaft
B.transmit engine thrust to the propeller shaft
C.absorb vibrations in the propeller shafting
D.prevent propeller thrust from being transmitted to the hul