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1、第 46 期轮机英语试题一、单项选择题1. In order to control thermal stresses ,some type of modern engines use piston with_.A. heavy wall and intensive coolingB. heavy wall and no coolingC. thin wall and no coolingD. thin wall and intensive cooling2. The average pressure exerted on a piston during each power stroke is
2、 termed_.A. indicated horsepower B. mean effective pressureC. exhaust back pressure D. compression pressure3. The ignition quality of a diesel fuel is indicated by the _.A. cetane number B. volatility point C. viscosity index D. octane number4. A piston in a four-stroke/cycle diesel engine makes fou
3、r strokes during each _.A. crankshaft revolution B. mechanical cycle of operationC. period of two combustion cycles D. cycle of two events5. Crankshafts of medium speed engines are _ from a single piece of steel.A. unusually solid welded B. never be solid forgedC. almost invariably solid forged D. a
4、lmost invariably be welded6. The starting air entering the cylinder begins when the piston_.A. has nearly come to the TDC B. has just past the TDCC. has nearly come to the BDC D. has just past the BDC7. A main bearing consists of two shells which are secured by means of studs and _.A. tie rods B. th
5、rough bolts C. lead wires D. bearing caps8. Compared to four-stroke/cycle engines, two-stroke/cycle diesel engines have the disadvantage of _.A. less even torque B. higher cylinder head temperaturesC. fewer power strokes per revolution D. greater weight/size requirements9._ controls the fuel oil tem
6、perature in order to provide oil at the correct viscosity for combustion.A. The viscosity regulator B. The temperature controllerC. The flow meter D. greater weight/size requirements10. In a diesel engine lube oil system, which of the following parts should be lubricated first?A. Camshaft bearings B
7、. Main bearings C. Piston crowns D. Cylinder walls11. A large, low-speed, main propulsion diesel engine uses sea water to directly cool the _.A. cylinder heads B. exhaust valves C. scavenging air D. injectors12. In a turbocharger, inlet air velocity is increased in the _.A. inlet nozzle ring B. stat
8、ionary diffuser passagesC. compressor outlet volute D. rotating impeller vanes13. Each cylinder has one starting valve which is usually opened by air pressure and closed by_.A. nuts and bolts B. new joints C. spring force D. sealing rings14. In a simple mechanical governor, the _.A. centrifugal forc
9、e rotates the ball-headB. flyweight centrifugal force is balanced by spring forceC. flyweight centrifugal force is balanced by hydraulic pressureD. speeder spring alone actuates the fuel control rod15. A pyrometer is an instrument commonly used to measure _.A. cylinder pressure B. flame intensityC.
10、exhaust gas temperature D. crankshaft axial alignment16. After starting a diesel engine, which of the listed operating conditions should be checked first?A. Air box pressure B. Lube oil pressure C. Exhaust temperatures D. Raw water pressure 17. A high temperature alarm or _ which will melt is used t
11、o guard against the explosion of compressor air pipelines.A. a flame trap B. a relief valve C. a fusible plug D. a bursting cap18. What preventative maintenance should be done frequently to diesel engines starting air receivers?A. Drain the accumulated moistureB. Test the relief valvesC. Watch the t
12、emperature to prevent fluctuation in pressureD. Clean the interior to remove oil and foreign matter 19. In reducing engine speed to an efficient propeller speed by the use of reduction gears, _.A. speed and torque are both reducedB. speed is reduced and torque remains unchargedC. speed is reduced an
13、d torque is increasedD. speed is sometimes unchanged while torque is increased20. Which of the following statements concerning fire-tube boilers is correct?A. Combustion gases flow through the tubesB. Flames impinge on the tubesC. Combustion occurs in the tubesD. Water flows through the tubes21. The
14、 exhaust boilers are used to recover some of _ carried in the exhaust gas from the main engine.A. water B. oil C. heat D. steam22. The water level in a steaming auxiliary boiler will always _.A. rise when the steam pressure is increasedB. remain constant as long as the feed pump operatesC. fall when
15、 the steam pressure is decreasedD. vary as the steam demand changes23. When lighting off an auxiliary boiler, which of the problems listed could cause the burners to sputter?A. Cold fuel oil B. Low fuel oil pressureC. Low atomizing steam pressure D. Water in the fuel oil24. If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the
