Exhaust valve grooving and corrosion is caused by certain components of residual fuel oilThese components are sodium, sulfur, and （）.

[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

[单选题]Leaky exhaust valve will result in which of the following?（）(1) high exhaust temperature;(2) low compression pressure;(3) low firing pressure.A . (1) and (2)B . (1) onlyC . (2) onlyD . (1),(2) and (3)

[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]With （）, the corrosion problems are much reduced in a central cooling system.A . no equipment in contact with sea waterB . less equipment in contact with fresh waterC . more equipment in contact with sea waterD . less equipment in contact with sea wa

[单选题]To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of （）.A . brassB . copperC . ironD . monel metal or stainless steel

[名词解释] 管道防腐（corrosion preventive of pipes）

[单选题]The rising of the exhaust temperature in manifold pipe may NOT result from （）.A . too great a loadingB . fouled turbochargerC . bad combustionD . excessive air

[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

[单选题]B．y comparing the exhaust gas temperature of each cylinder, the operator can determine if the load is balanced throughout the engine The device most commonly used is aA．tachometerB．pyrometerC．dynamometerD．calorimeter

[单选题]E．xhaust gas pyrometers are useful forA．detecting faulty combustion in individual cylindersB．adjusting fuel racks to maintain equal loading between cylindersC．adjusting the load limit setting of the governor at idle conditionsD．calculating engine hor