轮机英语真题45期,甲类三管轮.doc

轮机英语第45期 These acid residues must be prevented from entering the crankcase otherwise the lube oil would be _______ A. contaminated B .emulsified C deteriorated D .oxidated 2. The ratio of the brake horsepower to the indicated horsepower of a diesel engine is its _______ A. thermal efficiency B. mechanical efficiency C. brake thermal efficiency D. volumetric efficiency 3. The cetane number of a diesel fuel oil medicates its _________ A. viscosity B. acid content C. heating value D. ignition quality 4. The greatest turbulence in a diesel engine cylinder is created by the ________ A. shape of the combustion chamber B. fuel injection spray pattern C. cylinder swept volume D. degree of penetration of the fuel oil droplets 5. The projection on a shaft designed to change circular motion into up and down or back and fore motion is called ______ A. wheel B. crankshaft C. running gear D. cam 6. A clearly visible benefit of RT-flex engines is their ________operation at all ship speeds.This is achieved by the superior combustion performance. A. shockless B. smokeless C. no vibration D noiseless 7. A main bearing consists of two shells which are secured by means of studs and______ A. tie rods B. through bolts C. lead wires D. bearing caps 8. Compared to four-stroke/cycle engines, two-stroke/cycle diesel engines have the disadvantage of _________ A. less even torque B. higher cylinder head temperatures C. fewer power strokes per revolution D. greater weight/size requirements 9. ________controls the fuel oil temperature in order to provide oil at the correct viscosity for combustion A. The viscosity regulator B. The temperature controller C. The flow meter D. The pressure switch 10. A lubricant often has to perform many duties in any situation, in addition to it