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单选题
An axial轴向 piston pump differs from a radial piston pump as the pistons of an axial piston pump are positioned （）.
A
radially from the shaft
B
parallel to each other and to the shaft
C
parallel to each other but at a right angle to the shaft
D
at an angle to each other and to the shaft
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更多 “单选题An axial轴向 piston pump differs from a radial piston pump as the pistons of an axial piston pump are positioned （）.A radially from the shaftB parallel to each other and to the shaftC parallel to each other but at a right angle to the shaftD at an angle to each other and to the shaft” 相关考题
考题
The delivery rate of an axial piston hydraulic pump is controlled by varying the position of theA.tilting boxB.slide blockC.pintleD.reaction ring
考题
The usual number of single-acting pistons used in a variable stroke axial-piston pump isA.3 or 5B.5 or 7C.7 or 9D.9 or 11
考题
材料：A typical example of a hydraulic governor is the Woodward. This has adjustable droop for parallel operation and it is fitted with a speed-adjusting control . If required it can be fitted with a synchronizing motor to provide remote control from a switchboard.A gear pump driven from the engine supplies oil under pressure to accumulator pistons under which is a by-pass to regulate maximum pressure. One branch supplies oil which acts on top of the power piston, the pressure always tending to turn the terminal shaft to shut off fuel, while the other branch supplies oil to the pilot valve which is operated by the linkage from the fly weights above.Should the speed of the engine decrease due to increased load the flyweights will move towards their center of rotation and lower the position of the pilot valve plunger, admitting oil pressure from the bottom of the power piston. Since, however, the area on the bottom is much greater than the top the net resultant force causes the piston to move upwards. This operates the power lever turning the terminal shaft which varies the cut-off point in the fuel pump through linkage, but as the power piston moves up, the actuating compensating piston moves down.Oil under this piston is now forced through the needle valve to the receiving compensating piston, raising the outer end of the floating lever and the pilot valve plunger until it has returned to its normal position. This stops further movement of the terminal shaft so that the fuel control is now set in a position corresponding to the increased fuel required to run the engine at normal speed under the increased load.问题：This passage is mainly about ___.A.what type of governor should be provided when the engine is used for electric power generationB.why the speed of the engine fluctuatesC.how the governor worksD.how the fuel pumps workThe oil from the gear pump will ___. ① be supplied to the accumulator ② act on the power piston ③ be supplied to the pilot valveA.①B.①②C.②③D.①②③Which of the following is true about the Woodward discussed?A.It is a kind of mechanical governor.B.It can not be used for parallel operation.C.It has speed droop.D.It may only be manually controlled from a switch boarE.When the speed of the engine decreases due to increased load, which of the following will NOT happen?A.The flyweights move towards their centerB.The pilot valve plunger moves towards its normal positionC.The power piston moves downwards until it returns to its normal positionD.The terminal shaft moves to a new position请帮忙给出每个问题的正确答案和分析，谢谢！
考题
单选题The function of a centrifugal pump double volute casing is to （）.A
reduce radial thrust to the impellerB
double the liquid velocity through the pump when compared to a single voluteC
reduce hydraulic end thrustD
provide the effect of multi-staging
考题
单选题A variable displacement system of hydraulic drives consists of （）.A
a variable displacement axial piston pumpB
a constant displacement axial piston pumpC
a reciprocating piston pumpD
a centrifugal pump
考题
单选题The diameter of a piston is usually less at the crown than at the skirt, in order to （）.A
facilitate the installation of piston ringsB
allow for the expansion of the piston during operationC
prevent crankcase vapors from entering the combustion chamberD
reduce wearing of the upper cylinder liner
考题
单选题One of the main functions of wearing rings, as used in a centrifugal pump, is to （）.A
maintain radial alignment between the pump impeller and casingB
absorb all impeller shaft end thrustC
prevent water leakage to the atmosphereD
prevent wear of the pump casing and/or impeller
考题
单选题If a radial piston hydraulic pump fails to deliver rated fluid volume, the cause can be （）.A
contaminated fluidB
pitted thrust ringsC
worn pintle bearingsD
obstructed suctions passage
考题
单选题The function of the piston compression rings used in a diesel engine is to （）A
seal the space between the piston and linerB
transmit heat from the piston to the cylinder linerC
reduce the amount of combustion gas blow-byD
all of the above
考题
单选题The main purpose of the piston oil scraper rings is to （）.A
seal the space between the piston and the linerB
reduce the amount of lube oil burned in the combustion chamberC
transmit heat from the piston to the cylinder linerD
damp out fluctuations of the piston side thrust
考题
单选题If the water level dropped rapidly in the expansion tank of a closed diesel engine cooling water system, you should suspect a （）.A
loss of suction in the circulating pumpB
leak in the primary cooling systemC
broken raw water pump shaftD
burned or cracked piston in one cylinder
考题
单选题When the tilting box of a variable stroke axial-piston pump is perpendicular to the pump shaft, which of the following conditions will exist?（）A
The pistons reciprocateB
The ‘B’ end cylinder barrel rotatesC
There is no fluid flowD
Power is transmitted hydraulically
考题
单选题Which features of a centrifugal pump reduce the need for renewing worn impellers and pump casings?（）A
Close radial clearance between impeller hub and casingB
Low rotational speed of impellerC
Removable end plateD
Replaceable impeller and casing wearing rings
考题
单选题The delivery rate of a variable stroke axial piston hydraulic pump is controlled by varying the position of the （）.A
slide blockB
tilting boxC
pintleD
reaction ring
考题
单选题Low compression pressure in a diesel engine may be the result of （）A
insufficient fuel supply due to fuel pump valves sticking or leakingB
excessive mechanical clearance between the piston crown and cylinder headC
excessively worn fuel pump plungerD
excessive exhaust back pressure
考题
单选题Which of the following statements is/are true regarding hydraulic pumps in general? （）A
Variable volumes can be obtained with gear pumps only by variation of the pump drive speedB
A radial piston pump houses sliding pistons in a stationary cylinder block through which passes a rotating pintle or ported shaftC
The amount of fluid displaced per revolution of an axial piston rotary pump is dependent on the angle formed between the cylinder block and valve plateD
All of the above
考题
单选题The delivery rate of an axial-piston hydraulic pump is controlled by varying the position of the （）.A
sliding blockB
pintleC
reaction ringD
tilting box or swash plate
考题
单选题With reference to an axial piston pump, which one of the following statements is true?（）A
The cylindrical barrel is coupled to the motorB
The cylindrical barrel has an odd number of boresC
The bores end in socketsD
The sockets fit in the swash plate
考题
单选题An axial piston, variable stroke pump is used in a vessels hydraulic steering gearUnder pressure, oil continually leaks out from between the valve plate/cylinder barrel and will（）.A
cause loss of hydraulic oil from the systemB
result in extreme damage to the pumpC
cause damage to the pump ff not continually drained from the pump casingD
result in the system high side pressure to substantially drop off
考题
单选题In a radial piston pump, reversal and control of fluid flow are accomplished by moving the （）.A
central valveB
radial plungerC
floating ringD
cylinder body
考题
单选题With reference to a radial piston pump, which one of the following statements is false?（）A
Surrounding the fixed shaft is a hollow shaftB
This hollow shaft carries radial boresC
Each bore is fitted with a well-lapped plungerD
There are always even numbers of bores
考题
单选题The function of diesel engine piston compression rings is to （）.A
prevent piston side thrustB
prevent engine friction lossesC
transmit heat from the piston to the cylinder linerD
remove oil from the cylinder combustion space
考题
单选题Piston compression rings used in a diesel engine function to （）A
transfer heat from the cylinder to the pistonB
scrape oil from the sides of the pistonC
seal the combustion space from the crankcasesD
prevent any piston contact with the cylinder liner
考题
单选题A diesel engine piston crown can crack from （）A
excessive piston to liner clearanceB
excessive dirt beneath the piston crown that reduces heat transferC
faulty nozzle sprayD
all of the above
考题
单选题Which harmful consequence may be the result of lube oil sludge accumulation? （）A
Clogged oil pump suction screensB
Increased oil operating temperaturesC
Sticking piston ringsD
All of the above
考题
单选题A gudgeon pin in a trunk piston may be free to float and rotate, with （） to limit axial movement.A
split pinsB
crankpinsC
dipsticksD
circlips
考题
单选题The usual number of single-acting pistons used in a variable stroke axial-piston pump is （）.A
3 or 5B
5 or 7C
7 or 9D
9 or 11
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