13.___is simply a valve that measures the temperature of the coolant.

[单选题]If the coolant temperature of a closed cooling water system for a diesel enginegradually increases, the trouble usually is( ).A．a broken shaft on the freshwater pumpB．an excessive accumulation of scale in the heat exchangerC．an incorrect thermostatic

[单选题]The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.A . be jammedB . be openedC . be seatedD . be broke

[单选题]If an auxiliary diesel engine coolant temperature is higher than normal, but the thermostat is determined not to be defective, you would suspect a/anA．cavitation erosion in the water jacketsB．excess corrosion inhibitor in the coolantC．dirty jacket wa

[单选题]The needle valve in the injector （） at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.A . will liftB . will be liftedC . will closeD . will be closed

4.单选题（1分）The bicuspid valve is also known as the ___ valve.A. mitralB. aorticC.

[单选题]If the compensating needle valve of a hydraulic governor is opened more than necessary the governor will .A．have a larger than normal dead bandB．produce excessive speed response to a load changeC．respond slowly to any change in engine loadD．stabilize

[单选题]A． thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the superheat will result in a/anA．evaporator pressure decreaseB．evaporator coil over-feedC．evaporator capacity increaseD．expansion valve diap

[单选题]The expansion valve used in a refrigeration system regulates theA．superheat of the gas leaving the compressorB．back pressure in the evaporatorC．temperature in the refrigerated spaceD．degree of superheat of the gas leaving the evaporator

[单选题]Exhaust valve grooving and corrosion is caused by certain components of residual fuel oilThese components are sodium, sulfur, and （）.A . vanadiumB . carbonC . copperD . ash

[单选题]The opening of an exhaust valve on a modem, large, low-speed, main propulsion diesel engine may be actuated by （）.A . direct action of cam shaftB . compressed air pressureC . hydraulic “push rods”D . direct action of the main piston movin