【正文】 ine? A. To ignite the fuel. B. To insure pumping losses are held to a minimum. C. To increase fuel consumption. D. To keep exhaust temperature low. Jimei University 1018 The average exhaust temperature of a twostroke/cycle diesel engine with a turbinedriven supercharger is lower than a similar fourstroke/cycle diesel engine at equal loads because_____. A. twostroke/cycle diesel engines have a higher M. . than fourstroke/cycle diesel engines B. fourstroke/cycle diesel engine exhaust is cooled by scavenging air C. twostroke/cycle diesel engines have a lower . than fourstroke/cycle diesel engines D. the opening of the twostroke/cycle diesel exhaust ports or valves occurs much later than in fourstroke/cycle diesel engines Jimei University 1019 Diesel fuel oil having a low cetane rating can result in_____. A. improved cold weather starting B. smoother engine operation C. bustion knock D. reduce ignition lag 1020 The governor controlling a diesel engine modulates crankshaft RPM by adjusting the _____. A. intake air supply B. turbocharger speed C. fuel injection pumps D. engine speed droop Jimei University 1021 High exhaust temperature and black smoke exhausting from an auxiliary diesel engine can be caused by_____. A. engine overload B. low bustion temperature C. plugged fuel nozzle holes D. excessive pression pressure Jimei University 1022 Any increase in the exhaust back pressure of a fourstroke/cycle diesel engine will _____. A. reduce engine horsepower output B. aid in silencing the exhaust noise C. increase the mean effective pressure D. contribute to effective cylinder scavenging Jimei University 1023 The driving force of a propeller is transmitted to the hull through the_____. A. bevel gear teeth B. helically cut gear teeth C. sleeve bearings D. thrust bearing Jimei University 1024 If fuel injection to a fourstroke/cycle diesel engine begins earlier than designed, ignition may be delayed because the_____. A. cylinder pression pressure may not be high enough B. cylinder pression temperature may be too high C. fuel oil injection pressure may not be high enough D. scavenge and purge process is inplete Jimei University 1025 Which of the following problems can cause fluctuating pressures in the closed cooling system of a main propulsion diesel engine? A. Defective temperature controls in the system. B. Cavitation in the cooling water pump. C. Opened vent in the cooling system. D. Restricted water passages in the engine. Jimei University 1026 Which of the following statements concerning the factors affecting ignition delay is correct? A. An increase in intake air temperature will increase ignition delay. B. An increase in coolant temperature will decrease ignition delay. C. An increase in bustion chamber turbulence will increase ignition delay. D. An increase in pression ratio will increase ignition delay. Jimei University 1027 An increased pressure differential between the inlet and outlet of a strainer usually indicates the strainer is_____. A. holed B. fouled C. clean D. dirty 1028 A diesel engine with a bustion chamber located between the crowns of two pistons is known as a/an_____. A. doubleacting engine B. opposed pistons engine C. singleacting engine D. horizontal acting engine Jimei University 1029 Persistent knocking in one cylinder of an eight cylinder diesel engine would MOST likely be caused by_____. A. using fuel oil with low cetane number B. a badly worn piston pin C. a loose flywheel key D. a loose bed plate bolt Jimei University 1030 To successfully reduce an excessively high diesel engine exhaust gas temperature, you should_____. A. reduce the engine driven fuel pump outlet pressure B. retard the fuel injector timing to reduce power C. increase the fuel rack setting D. reduce the load on the engine Jimei University 1031 Which of the two events listed occurs simultaneously in a twostroke/cycle diesel engine? A. Exhaust and scavenging B. Scavenging and pression C. Ignition and expansion D. Exhaust and pression Jimei University 1032 To determine if the lube oil filter elements need changing, _____. A. open the filter and inspect the elements B. check the lube oil pump discharge pressure C. check the lube oil header pressure D. check the pressure drop across the filter Jimei University 1033 Diesel engine control can be obtained by the bridge_____. A. at any time B. only after the engine room control station is switched to bridge control C. whenever the secondary station is switched to bridge control D. with the approval of the chief engineer only Jimei University 1034 The direct cause of a crankcase explosion can be attributed to_____. A. extremely hot scavenge air B. excessive cooling water temperature C. an overheated bearing D. excessive lube oil in the crankcase Jimei University 1035 Combustion knock can occur in the cylinders of a diesel engine under any condition permitting_____. A. a shortened ignition delay period B. a lean fuel/air mixture C. excess fuel in the bustion chamber D. rapid vaporization of injected fuel droplets Jimei Unive