【正文】 temperature in a diesel engine closed freshwater cooling system is normally controlled by_____. A. regulating the level of corrosion inhibitor in the primary cooling system B. the level of the freshwater expansion tank C. varying the engine load to meet temperature requirements D. the operation of the thermostatic valve Jimei University 0877 On a turbocharged, mediumspeed diesel engine, which of the following problems is an indication of a restricted air intake passage? A. Engine is hard to start B. Engine misses C. Surges at governed RPM D. Coolant temperature is too low 0878 The water in an operating auxiliary boiler should be tested for alkalinity and chloride content each_____. A. hour B. day C. week D. month Jimei University 0879 The closing of the exhaust valves used on a modern, large, lowspeed, main propulsion diesel engine may be directly provided by_____. A. large conical springs B. pressed air pressure C. hydraulic pressure D. exhaust gas pressure Jimei University 0880 In a twostroke/cycle diesel engine, the camshaft rotates at_____. A. twice the crankshaft speed B. half the crankshaft speed C. the same speed as the crankshaft D. a speed independent of the crankshaft Jimei University 0881 An indication of a diesel engine air intake being partially clogged, is_____. A. low firing pressure and low exhaust temperatures B. low firing pressure and normal exhaust temperatures C. high firing pressure and low exhaust temperatures D. high firing pressure and high exhaust temperatures *空氣量不足影響爆炸壓力 ,排溫正常 . Jimei University 0882 An important design characteristic of an explosion relief valve for a diesel engine is the ability to_____. A. open slowly to permit a gradual reduction of crankcase pressure B. open quickly against crankcase pressure to prevent a possible implosion C. close quickly in order to prevent an inrush of air D. close slowly to permit proper seating of the valve disc and neoprene sealing surfaces Jimei University 0883 If a fourstroke/cycle diesel engine is running at 1550 RPM, the speed of the camshaft will be_____. A. 525 RPM B. 775 RPM C. 1550 RPM D. 1800 RPM 0884 For proper operation, auxiliary boiler feed water must have which of the following characteristics? A. High oxygen concentration B. Low pH C. Proper alkalinity D. All of the above Jimei University △ 0885 The most mon cause of scale formation in an auxiliary boiler is_____. A. concentrations of calcium sulfate (硫酸鈣 )in the boiler water B. fuel oil in the feed water C. improper treatment of the feed water with calcium sulfate D. excessive feed water alkalinity Jimei University 0886 If over a period of weeks the airbox pressure of a turbocharged, diesel engine, operating at full load, appears to be dropping off↓, the cause can be_____. A. open airbox drains B. loss of cooling water to the diffuser C. gradual fouling of the air filters D. improperly timed exhaust valves Jimei University 0887 Before an auxiliary boiler is shutdown for an extended period of time, the water in the boiler should have a pH value of_____. A. 10 B. 7 C. 4 D. 1 *停爐保養(yǎng)應(yīng)使?fàn)t水帶微堿性 . Jimei University 0888 The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to _____. A. assist in a quick cutoff of fuel injection B. allow oil backflow from the injector to the helix C. reduce fuel oil pressure between injection strokes D. meter the quantity of fuel delivered *jerk pump： 脈動(dòng)作用泵 , 高壓燃油噴射泵 Jimei University 0889 Excessive alkalinity of the water in an auxiliary boiler can cause_____. A. caustic embrittlement苛性 (的 )脆化 of the boiler metal B. acidic corrosion of the boiler metal C. hard scale deposits on the boiler tubes D. etching侵蝕 of the heat exchange surfaces Jimei University 0890 The procedures remended for auxiliary boilers having high salinity include_____. A. treating with oxygen scavengers B. securing (保全之意 — 停爐 )the boiler and giving it a blowing down C. increasing the pH D. reducing the phosphate磷酸鹽 level Jimei University 0891 Which of the following conditions may need to be reduced when operating a large, low speed, main propulsion, diesel engine at low loads? A. injection pressures B. control air supply pressure C. cooling water flow through after coolers D. lube oil temperature Jimei University 0892 Improper maintenance of the fuel oil burners in an automatically fired auxiliary boiler, could result in_____. A. increased fuel consumption B. increased feed water consumption C. fuel pump failure D. bustion control system failure Jimei University 0893 The upper piston rings in large, slowspeed, twostroke/cycle diesel engines are most effectively lubricated by oil_____. A. fed from mechanical lubricators B. Thrown off from the main bearings C. supplied from wick fed drip lubricators D. flow from a centrifugal or banjo oiler 圓形加油壺 Jimei University 0894 Operating a diesel engine for prolonged periods, with a closed freshwater cooling system, at temperatures lower than the normal design temperature can cause_____. A. the formation of sulfuric acid B. a decr