【正文】 er volumes at bottom dead center and at top dead center C. engine cylinder size to piston size D. the number of pression strokes for a given horsepower Jimei University 1079 White smoke exhausting from an operating diesel engine may indicate_____. A. a cracked liner B. burning lube oil C. an overloaded engine D. insufficient bustion air Jimei University *1080 If the main engine of an unattended engine room shuts down automatically, it will be indicated by an alarm_____. A. at each control station B. in the chief engineer39。s quarters C. in the captain39。s quarters住處 D. All of the above are correct Jimei University *1081 In diesel engines, the four basic events (intake, pression, power and exhaust) are performed once in_____. A. two crankshaft revolutions in a twostroke/cycle engine B. two power strokes in a twostroke/cycle engine C. one power stroke in a twostroke/cycle engine D. two piston strokes in a twostroke/cycle engine Jimei University 1082 Engine protection by means of an alarm or shutdown control can be obtained with devices that are sensitive to_____. A. temperature B. pressure C. engine speed D. all of the above Jimei University 1083 Maximum horsepower of a diesel engine is attained_____. A. when the engine RPM is pulled down by overload B. at rated engine RPM C. at 95 % of rated engine RPM D. at 95 % of a properly adjusted governor RPM with the engine under full load Jimei University 1084 The main purpose of the piston oil scraper rings is to_____. A. seal the space between the piston and the liner B. reduce the amount of lube oil burned in the bustion chamber C. transmit heat from the piston to the cylinder liner D. damp out fluctuations of the piston side thrust Jimei University 1085 What causes diesel fuel to be ignited in the cylinder of an operating diesel engine? A. Spark plug火花塞 B. Heat of pression C. Carburetor汽化器 D. Glow plug發(fā)光 , 發(fā)熱 1086 The highest pressure in a diesel engine cylinder normally occurs_____. A. at TDC B. before TDC C. after TDC D. during air starting Jimei University 1087 How many power strokes per crankshaft revolution are there in an eight cylinder, two stroke/cycle diesel engine? A. One B. Two C. Four D. Eight Jimei University *1088 The most important factor in engine performance is the actual power output at the end of the crankshaft available for doing work. This is known as_____. A. indicated horsepower B. brake horsepower C. horsepower D. friction horsepower Jimei University 1089 When fuel oil has seriously contaminated a diesel engine lubricating oil, you should _____. A. filter to remove the fuel oil B. use the settler to remove the fuel oil C. remove the fuel oil by centrifuging D. drain and then renew the lube oil supply Jimei University 1090 A vane pump belongs to_____ according to its working principle. A. reciprocating pump B. positive displacement pump C. centrifugal pump D. centripetal pump向心泵 1091 Through a_____ pump, the liquid is transferred from the suction to the discharge by the mechanical variation of the volume of a chamber or chambers. A. positive displacement B. ejector C. centrifugal D. air pressor Jimei University 1093 The gear and screw pumps are classified as_____. A. variable stroke pumps B. multistage pumps C. positive displacement pumps D. tripleported pumps 1094 Gear pumps are of positive displacement type pumps because they discharge a near constant amount of liquid_____ pressure. A. depending on B. in relative to C. regardless of D. because of Jimei University 1095 A gear pump belongs to_____ according to its working principle. A. reciprocating pumps B. positive displacement pumps C. centrifugal pumps D. centripetal pumps 1096 The pressure head of a pump is given in the unit of_____. A. kg B. MPa C. meter fluid column D. None of the above is true. Jimei University 1097 A centrifugal pump produces the required pressure energy by means of a rotating _____ provided with vanes. A. propeller B. impeller C. circumference D. screw 1098 The discharge flow of a reciprocating pump is_____. A. steady B. in pulsation C. continuous D. large Jimei University 1099 In a_____ the center screw is driven and the outer screws idle. A. single screw pump B. doublescrew pump C. triple screw pump D. centripetal pump 1100 A Screw pump belongs to_____ according to its working principle. A. reciprocating pumps B. positive displacement pumps C. centrifugal pumps D. centripetal pumps Jimei University *1101 The amount of fluid delivered by a screw pump can be regulated by_____. A. throttling the pressure line B. changing the speed of the rotor C. either A or B D. None of the above is tree. 1102 While flowing through the volute in a centrifugal pump, part of the_____ energy of the liquid is converted to_____ energy. A. kiic/pressure B. kiic/essential C. pressure/kiic D. pressure/height Jimei University 1103 The amount of fluid delivered by a centrifugal pump can be regulated by_____. A. throttling the pressure line B. changing the speed of the rotor C. eithe