更多"The crankshafts of medium speed eng"的相关试题:
[单项选择]Crankshafts of medium speed engines are （） from a single piece of steel.
A. unusually solid welded
B. never be solid forged
C. almost invariably solid forged
D. almost invariably be welded
[单项选择]Although the crankshafts of medium diesel engines appear to be robust, they rely on the support of （） to develop their full strength.
A. the piston rods
B. the crank throws
C. the thrust bearings
D. the main bearings
[单项选择]Pistons of marine medium speed diesel engines may be made of （） in order to keep the weight down for balancing purpose at high speed.
A. lead
B. forged steel
C. alloy steel
D. aluminum alloy
[单项选择]Medium speed engines have a （） power to weight ratio than the slow speed two strokes, but due to the higher speeds tend to have （） maintenance intervals.
A. higher；reduced
B. higher；increased
C. lower；reduced
D. lower；increased
[单项选择]Prior to starting most medium-speed propulsion diesel engines, which of the procedures listed should be observed?（）
A. The expansion tank should be topped off
B. The thermostatic water regulating valves should be manually opened
C. The fuel filters should be changed
D. The engine should be turned over slowly with the indicator cocks open
[单项选择]On a turbo-charged, medium-speed 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
[单项选择]On a medium-speed main propulsion diesel engine, the crank-pin or crank journal bearings receive lubricating oil from （）.
A. a spindle lubricator
B. an oil jet
C. internal splashing
D. drilled passages in the crankshaft
[单项选择]Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）
A. must churn the oil in the sump
B. is connected to the propeller shaft
C. is driven at the highest RPM
D. compensates for alignment variations between the engine and pinion gear
[单项选择]The majority of medium speed and high speed marine diesel engines for main or auxiliary drive operate on the （） cycle.
A. two-stroke
B. four-stoke
C. long-stroke
D. short-stroke
[单项选择]
In a medium speed diesel engine, a trunk type piston may be cooled by（）
Ⅰ.oil circulation though passages in the piston crown
Ⅱ.heat transfer through piston rings and liner wall
A. Ⅰ only
B. Ⅱ only
C. either Ⅰ or Ⅱ
D. neither Ⅰ or Ⅱ
[单项选择]Each cylinder liner on the marine medium speed engines （）.
A. is usually cooled by sea water
B. can be replaced when worn out
C. is in direct contact with the water in the bore of the cylinder
D. can t expand when heated
[单项选择]The term medium speed diesel engine is currently taken to mean an engine with an operating rotational speed of （） rpm.
A. below 300
B. above 1200
C. between 300 to 1200
D. below 1200
[单项选择]Most medium and slow speed diesels are started by what medium?（）
A. Electric starting motors
B. Hydraulics
C. Compressed air
D. Ether
[单项选择]Critical speed in diesel engines occurs when engine torque pulsations become （）
A. opposed to the crankshaft rocking couple
B. resonant with the crankshaft natural frequency
C. critical fore and aft crankshaft vibrations
D. horizontal whipping motions of the crankshaft
[单项选择]One end of a cylinder for a medium or high-speed diesel engine is sealed by the piston and rings, the other end is sealed by the （）
A. crankcase
B. cylinder head
C. valve cover
D. engine frame
[单项选择]In slow speed two-stroke engines,（）the fresh air entering begins when and stops as（）
A. the inlet port is opened by the up coming piston； the port is closed by the down going
B. the inlet valve is opened by the down going piston；the inlet valve is closed
C. the inlet port is opened by the down going piston；the port is closed by the up coming
D. the inlet valve is opened
[单项选择]Passages are drilled in the crankshafts of diesel engines to provide lubricating oil to the （）.
A. main bearings
B. connecting rod bearings
C. piston pin bushings
D. All of the above
[单项选择]Today, crankshafts for large 2-stroke crosshead engines are of the （）type.
A. semi-built
B. built-up
C. solid forged
D. individual forged
[单项选择]The crankshafts on the large modern 2-stroke crosshead engines are （）big （）makes as a single unit and so are constructed by joining together individual forgings.
A. enough；to
B. too；to
C. such；so
D. so；that
