问题：
[单选] Combustion knock occurring in a diesel engine can be caused by （）.
excessive fuel penetration。prolonged injection lag。reduced ignition lag。prolonged ignition lag。
问题：
[单选] In using reduction gears to obtain efficient propeller speeds, （）.
they must be located at the after end of the engine。they can only be used with one engine at a time。they eliminate the need for controllable pitch propellers。they are connected to the engine with a flexible coupling。
问题：
[单选] Lube oil cannot be efficiently filtered if its （）.
viscosity is too low。temperature is too low。pump discharge pressure is higher than the systems pressure。pump capacity is greater than the systems need。
问题：
[单选] For a given size engine, the two-stroke/cycle diesel engine will deliver more power than a four-stroke/cycle diesel engine because （）.
it has a longer power stroke。more air gets into the cylinder each stroke。it develops twice as many power strokes at the same speed。higher combustion pressure is developed。
问题：
[单选] The minimum speed an engine must attain before ignition can occur depends upon （）.
the type and size of the engine。the condition of the engine。ambient temperature。all of the above。
问题：
[单选] An automated diesel engine should normally shut down due to （）
low lube oil temperature。high ambient air temperature。low tube oil pressure。high exhaust system back pressure。
问题：
[单选] Proper filtering and straining of fuel oil is important because the （）.
fuel oil pump will over-speed if dirt is not removed。fuel oil transfer pumps cannot tolerate small amounts of dirt in the oil。fuel injectors may be damaged by foreign particles in the fuel oil。dirty fuel will clog the intake air filter。
问题：
[单选] Lube oil filters remove contaminants more efficiently if the oil being filtered is （）.
under high pressure。under low pressure。heated to reduce viscosity。cooled to increase viscosity。
问题：
[单选] What is the function of the thrust bearing?（）
Prevents lateral movement of the slow speed gear。Transmits propeller thrust to the hull。Keeps spring bearings in line。Prevents main reduction gear axial movement。
问题：
[单选] The ability of the governor to prevent fluctuations in engine speed is termed （）.
sensitivity。stability。promptness。speed droo。
