In a diesel engine, exhaust valves open before the intake ports are uncovered to （） Ⅰ.reduce pumping losses Ⅱ.reduce back pressure

相似题目

• Excessive piston ring wear in a diesel engine will cause（）

  A . high lube oil viscosity B . increased lube oil consumption C . low lube oil temperatures D . high firing pressure

  查看最佳答案

• A turbocharged, four-stroke/cycle diesel engine has a larger valve overlap than a naturally aspirated four-stroke/cycle diesel engine, in order to in crease the （）.

  A . temperature of the exhaust gases B . energy supplied to the turbocharger C . air pressure to the intake manifold D . purge of exhausted gases from the cylinder

  查看最佳答案

• Engine coolant accumulating in the diesel engine lubricating oil can result from a （）

  A . low oil pressure B . high coolant pressure C . leaking fuel injector D . cracked cylinder head or liner

  查看最佳答案

• A supercharged diesel engine when compared to a similar naturally aspirated diesel engine, will develop an increase in （）

  A . ignition lag B . engine horsepower C . lube oil system pressure D . specific fuel consumptio

  查看最佳答案

• Defective timing gear in a diesel engine may lead to （）.

  A . smoky exhaust B . starting failure C . overload D . over speed

  查看最佳答案

• Worn main bearings in a diesel engine can result in （）

  A . decreased compression pressure B . increased lube oil pressure C . lower lube oil temperature D . excessive leakage past the piston ring

  查看最佳答案

• The intake valves in a diesel engine are reseated by （）.

  A . cam followers B . push rods C . combustion gases D . valve spring

  查看最佳答案

• Burning fuel with a high sulfur content in a diesel engine will （）

  A . increase thermal efficiency B . cause clogging of the fuel system C . increase the ability of the engine to start in cold weather D . produce corrosion in the cylinder and exhaust system at low load

  查看最佳答案

• Fuel is ignited in a diesel engine cylinder by （）

  A . a spark plug B . injectors C . the heat of compression D . increasing jacket water temperature

  查看最佳答案

• Improperly fitted piston rings in a diesel engine can cause（）

  A . excessive lube oil consumption B . lower than normal lube oil temperature C . higher than normal exhaust back pressure D . excessive crankshaft end play

  查看最佳答案

• Poor combustion in a diesel engine can be caused by （）.

  A . high compression pressure B . low intake air temperature C . low exhaust pressure D . high scavenge air pressure

  查看最佳答案

• A diesel engine is supercharged in order to（）

  A . lower the no-load RPMs B . provide more air for combine with the fuel C . increase the no-load RPMs D . provide more fuel combine with the air

  查看最佳答案

• Low compression pressure in a diesel engine is caused by（）

  A . low water in the expansion tank B . improperly seated valves C . low fuel oil pressure D . worn or broken cylinder liner sealing ring

  查看最佳答案

• If a crankcase explosion occurs in a diesel engine, you should stop the engine and（）

  A . immediately open all crankcase relief ports B . increase crankcase exhauster speed to draw cool air into the engine C . allow the engine to cool naturally D . increase crank case scavenge air to remove unburned gase

  查看最佳答案

• A defective injector nozzle in a propulsion diesel engine can cause（）

  A . engine power losses B . smoking due to unburned fuel C . high exhaust temperature readings D . all of the above

  查看最佳答案

• Low compression in a diesel engine can be caused by （）

  A . clogged coolant passages B . a leaking cylinder head gasket C . low fuel oil pressure D . worn or broken cylinder liner sealing ring

  查看最佳答案

• Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because（）.

  A . The direction of pressure on the journal in four-stroke engine is continuously B . positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine C . four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines D . Low-stroke engines usually consume less lube oil than four-stroke engine

  查看最佳答案

• A diesel engine burns （） a gasoline engine of the same capacity in the same period of time.

  A . as much fuel as B . less fuel than C . less fuel as D . more fuel tha

  查看最佳答案

• Defective governor in a diesel engine may lead to （）.

  A . smoky exhaust B . starting failure C . ignition relay D . over speed

  查看最佳答案

• A restricted air intake to a diesel engine may result in the engine （）.

  A . failing to reach rated speed B . knocking under maximum load C . hunting or surging under light load D . overspeeding and running away

  查看最佳答案

• Defective air cooler in a diesel engine will lead to （）.

  A . smoky exhaust B . starting failure C . overload D . over speed

  查看最佳答案

• The highest pressure in a diesel engine cylinder normally occurs （）.

  A . at TDC B . before TDC C . after TDC D . during air starting

  查看最佳答案

• In a diesel engine, blow-by（）

  A . increase exhaust back pressure B . causes excessive crankcase pressure C . can only be detected by a compression check D . decreases fuel consumptio

  查看最佳答案

• Low compression in a diesel engine could be caused by（）

  A . worn or broken cylinder liner sealing rings B . high cooling water temperature C . worn or broken piston rings D . low fuel oil pressure

  查看最佳答案