轮机英语题库 柴油机基本知识

The term refers to one complete sequence of operations required to produce power in an engine. A. diesel engine B. stroke C. cycle D. compression ratio 62. The is the power available at the output shaft of the engine and can be measured using a torsionmeter or with a brake. A. electric power B. shaft power C. indicated power D. mechanical power 63. VIT means . A. variable injection timing B. variable inlet tonnage C. vertical incoming tonnage D. vertical incoming tank 64. Supposed the rated capacity of the main engine of a ship is 10000kw at 100 rated r/min, then when at 80r/min its capacity should be . A. 800kw B. 5120kw C. 6400kw D. 4180kw 65. Engine displacement is equal to the cylinder . A. area times the stroke B. area times the stroke, times the number of cylinders C. volume times the stroke D. volume times the stroke, times the number of cylinders 66. In describing engine operation, what does the term“cycle”mean? A. The sequence of events that produce a power pulse. B. One rotation of the engine crankshaft C. One stroke of a piston D. All of the above 67. The time between injection and ignition of the fuel is known as . A. turbulence B. after burning ratio C. pre-ignition lag D. ignition delay 68. The compression ratio of the diesel engine refers to the ratio between the . A. piston area to connecting rod length B. cylinder volumes at bottom dead center and at top dead center C. engine cylinder size to piston size D. the number of compression strokes for a given horsepower 69. The most important factor in engine performance is the actual power output at the end of the crankshaft available of doing work. This is known as_____. A. indicated horsepower B. brake horsepower C. net horsepower D. friction horsepower 70. The injection 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 71. A clearly visible benefit of RT-flex engine is their _____ operation at all ship speeds. This is achieved by the superior combustion performance. A. shock less B. smokeless D. no vibration D. noiseless 72. 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 73. Compared to four-stroke/cycle engines, two-stroke/cycle 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 74. 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 75. In order to control thermal stresses, some types of modern engines use pistons with_____. A. heavy wall and intensive cooling B. heavy wall and no cooling C. thin wall and no cooling D. thin wall and intensive cooling 76. A piston in a four-stroke/cycle diesel engine makes four strokes during each_____. A. crankshaft revolution B. mechanical cycle of operation C. period of two combustion cycles D. cycle of two events 77. Crankshafts of medium speed engines are _____ from a single piece of steel. A. unusually solid welded B. never be solid forged C. almost invariable solid forged D. almost invariable be welded 78. In a two-stroke engine the crankshaft rotates at _____ the engine rotational speed. A. half B. twice C. the same speed as D. four times 79. A diesel engine is similar to a gasoline engine except that the former has no_____. A. cross-head B. cylinder C. connecting rod D. spark plug 80. However fast or slow the combustion rate, it is still a _____between carbon, hydrogen, sulphur and oxygen that release heat. A. physical deformation B. state exchange C. chemical reaction D. coalescence 81. _____of different thickness are inserted between the shells to enable adjustment of the bearing clearances. A. Screws B. Films C. Discs D. Shims 82. The gas loads on the engine structure are constrained by means of hydraulically preloaded _____which connect the bedplate, frame sections and cylinder jackets into a single unit. A. connecting rods B. main bearing C. column D. tie rods 83. Which of the flowing statements represents the function of the compression rings installed at the top of a diesel engine piston? A. Control the amount of lube oil burned in the combustion chamber B. Transmit heat from piston to the cylinder liner C. Prevent damage to ring groove inserted by acting as a heat dam D. Dissipate combustion chamber pressure by channeling it through the ring gap 84. In a diesel engine, _____offers the heat energy directly; _____works as working medium and changes the heat energy to mechanical energy. A. the burning of the fuel, medium shaft B. fuel spray, fresh air C. fuel, fuel spray D. the burning of the fuel, the burned gas mixture 85. In a diesel engine, _____works as working medium and changes the heat energy into mechanical energy, _____changes the reciprocating movement to rotary movement. A. fuel spray, the burning of the fuel B. the burned gas mixture, connecting rod C. medium shaft, crankshaft D. the burned gas mixture, piston rod 86. One of the differences between a two-stroke engine and a four-stroke engine is_____. A. a two-stroke engine works without exhaust operation B. a two-stroke engine works without compression stroke C. a two-stroke engine works without expansion stroke D. a two-stroke engine works without suction stroke 87. One of the differences between a two-stroke engine and a four-stroke engine is_____. A. a two-stroke engine can’t work without cylinders B. a two-stroke engine can’t work without pistons C. a two-stroke engine can’t work without crankshafts D. a two-stroke engine can’t work without a blower 88. In a diesel engine, when the fuel is injected into the cylinder, _____. A. the piston is just coming upward from the bottom dead center B. the piston has moved about one-fifth of the way up C. the piston has moved most of the way up and almost reached the TDC D. the piston has just past the TDC 89. _____is the main reason that reduces the power advantage of a two-stroke engine over a same size four-stroke one to about_____. A. inefficient scavenging, twice B. Inefficient scavenging, 1.8times C. Fewer strokes in a circle, twice D. Fewer strokes in a circle, 1.8 times 90. If the engine is naturally aspirated, or is a small high-speed type with a centrifugal turbocharger, the period of valve overlap, i.e. when both valves are_____, will be_____, and the exhaust valve will close some 10_____top dead center. A. open, short, after B. closed, short, after C. open, long, before D. closed, long, before 91. In a two-stroke engine, there are always a series of openings known as_____, and in some circumstances, there are also openings known as_____, in the part of the cylinder liner inside the scavenging air box. A. scavenging air ports exhaust ports B. inlet ports, scavenging air ports C. scavenging air ports, inlet ports D. exhaust ports, inlet ports 92. In some type of two-stroke engines, besides some small holes for_____, starting valve, safety valve, indicator cock, and so on, there is a large central opening in each cylinder cover for mounting the_____. A. fuel valves, exhaust valve B. exhaust valves, inlet valve C. fuel valves, inlet valve D. exhaust valves, fuel valve 93. IN a two-stroke engine, the piston consists of a lower part, which is named as _____and usually made of_____, and a n upper part, which is referred to as _____and made of_____. A. low-half, cast iron, top half, heat-resistant steel B. low-half, aluminum, top-half, stainless steel C. piston skirt, cast iron, piston crown, heat-resistant steel D. piston skirt, aluminum, piston crown, stainless steel 94. In order to keep the oil film on the cylinder liner during the running-in period, the piston rings are slightly rounded_____. A. on both the external and internal top edges B. on both the external top and bottom edges C. on both the external and internal bottom edges D. on all the four edges 95. In order to improve the working conditions of the crosshead bearings, the bearing pressure is made _____and the peripheral speed is made _____in later designs. A. smaller, higher B. higher, smaller C. smaller, smaller D. higher, higher 96. The guide shoes are secured to the crosshead by means of_____. A. through bolts B. end chock bolts C. side chock bolts D. tap bolts 97. The pistons are cooled by oil _____the forced lubrication system. A. supplied from B. supplying to C. being supplied for D. to be supplied to 98. Sealing between the crankcase and the scavenging air boxes is achieved by means of_____. A. the connecting rod stuffing boxes B. the piston stuffing boxes C. the sealing rings of piston D. the scraper rings of pistons 99. Each stuffing box is provided with two sealing rings and three_____. A. packing B. rubber rings C. distributor rings D. scraper rings 100. The sealing rings are in for parts and pressed together around the piston rods by means of _____. A. coil spring B. lead wires C. welding D. adhesive paste 101. In a four stroke engine, which process lasts the longest period? A. Exhaust and suction process B. Suction and compression C. Combustion and exhaust process D. Working and exhaust process 102. Propulsion engines and the vast majority of auxiliary generator engines are designed to allow a generous through-flow of scavenge air in order to control_____. A. the lubricating oil consumption B. the turbine blade temperature C. the flow rate of fuel D. scavenge air pressure 103. In today’s practice, with cylinders of equal diameter of bore and equal revolutions, the two-cycle engines delivers a power about 80 percent_____ than that of the four-stroke one. A. greater B. better C. smaller D. Less 104. To prevent excessive _____in the transverse girders, the tie bolts are positioned as close to the center of the crankshaft as possible. A. thermal stresses B. bending moments C. thermal loads D. surface tension 105. A built-up exhaust valve is one in which_____. A. the stem and the heads are made of the different materials B. low-ally steel is used throughout C. a replaceable valve disk is welded to the head D. the self-centering action comes from motion of the valve stem in the guide