单项选择题The minimum fuel oil delivery pressure required for diesel engine injection depends primarily on the()

A.degree of cylinder air turbulence
B.firing pressure in the engine
C.quality of fuel to be injected
D.duration of the ignition delay period


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1.单项选择题One method of determining crankshaft misalignment is by()

A.laying a straight edge across the crank webs at the crankpin and measuring the distance to the crankpin in two places
B.measuring the crank drop on either side of each crank throw while the crankshaft is slowly rotated through one revolution
C.rotating the crankshaft through one revolution, pausing each 90oof rotation to measure bearing clearances, top and bottom
D.taking micrometer reading between the crank cheeks opposite the crankpin every 90°of crank angle rotation

2.单项选择题Heat for igniting the fuel oil in the cylinder of a diesel engine is generated by the ()

A.electronic ignition system
B.compression of air by the piston
C.friction in the fuel injector
D.fuel oil bearing system

3.单项选择题Diesel engine crankshaft deflection readings are generally taken at four crank positionsGood engineering practice requires the deflection gage or indicator to be()

A.placed as near the crankpin axis as possible
B.removed each time the crankshaft is repositioned
C.left in place for all four readings
D.reset to zero for all four readings

4.单项选择题Fuel oil injected into the cylinder of a diesel engine just after the piston passes top dead center, will()

A.increase engine power
B.increase engine load
C.decrease engine power
D.improve fuel economy

5.单项选择题Diesel engine injection lag is caused by()

A.compressibility of the fuel
B.high fuel oil supply flow
C.scored plunger and barrel packing
D.excessive air turbulence

6.单项选择题Abnormal crankpin bearing and piston skirt surface wear indicate()

A.a restricted air intake
B.a clogged connecting rod oil passage
C.incorrect connecting rod alignment
D.high cylinder firing temperatures

7.单项选择题Injection lag in a diesel engine may be caused by()

A.a higher cetane number of fuel oil
B.the diesel fuel used having a high viscosity
C.mechanical rigidity in the lube pump mechanism
D.a decrease rigidity in the fuel pump delivery pressure

8.单项选择题Which of the following relationships should occur between the temperature developed in a combustion space, and the compression ratio of the engine?()

A.Higher compression ratios create higher temperature
B.Higher temperatures create higher compression ratios
C.low temperatures create higher compression ratios
D.Higher compression ratios create low temperatures