问题：
[单选] The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and （）.
reduce water temperature。reduce water turbulence。provide an air cushion。allow for an increase in water volume as the engine warms u。
问题：
[单选] To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of （）.
brass。copper。iron。monel metal or stainless steel。
问题：
[单选] Which of the following statements describes the function of an expansion tank in a diesel engine cooling system?（）
Maintains a constant head on the system。Reduces the likelihood of air or steam pockets formation。Provides a low pressure point for the addition of makeup cooling water。All of the above。
问题：
[单选] Prior to lighting off a cold automatically fired auxiliary boiler, you should （）.
check and regulate the water level。close the air cock once fires are lit。blowdown the gage glass。crack the steam stop to assure protective steam flow。
问题：
[单选] One method of constructing large marine diesel engines and reducing the total engine frame weight is through （）.
casting interlocking components。welding plates to form sections for assembly。forging integral components。case hardening integral component。
问题：
[单选] Which of the following statements is true concerning an oil cooler?（）
The oil temperature is less than the cooling water temperature。The oil pressure is less than the cooling water pressure。The oil pressure is greater than the cooling water pressure。The oil flow control valve is always installed in the oil input line。
问题：
[单选] The device allowing for the change in volume of the cooling water in a propulsion diesel engine closed cooling system is the （）.
fresh water expansion tank。sea water expansion tank。thermostatic expansion valve。jacket water cooler accumulator。
问题：
[单选] Scavenging in a four-stroke/cycle diesel engine occurs during the （）.
last part of the exhaust stroke, and the first part of the intake stroke。last part of the intake stroke only。early part of the injection stroke only。early part of the power stroke。
问题：
[单选] The color of the exhaust from a diesel engine should be （）
clear。hazy light brown。hazy light blue。hazy light grey。
问题：
[单选] In a large, slow-speed, main propulsion diesel engine, which of the parts listed is under tension when the engine is running?（）
Bed plate。Column。Entablature。Tie rod。
