-
The camshaft on a four-stroke/cycle diesel engine provides a means to operate the ().
A . fuel injectors
B . exhaust valves
C . intake valves
D . all of the above
-
A connecting rod in a four-stroke/cycle diesel engine is subject to()
A . tension load twice each crankshaft revolution
B . compression load during power and compression strokes
C . inertia load once every four crankshaft revolutions
D . bending loads at bottom and top dead center
-
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
-
In a four-stroke cycle diesel engine the intake valves open ()
A . before TDC and close after BDC
B . after TDC and close after BDC
C . before TDC and close before BDC
D . after TDC and close before BDC
-
What is the crank angle between any two crank throws in the firing order of a four-stroke/cycle, in line, eight cylinder diesel engine?()
A . 45
B . 60
C . 90
D . 100
-
Air motion is induced in a four-stroke/cycle diesel engine cylinder to improve air fuel mixing, and is known as()
A . supercharging
B . scavenging
C . turbulence
D . swept volume charging
-
Turbocharged four-stroke/cycle diesel engines utilize valve overlap for().
A . improving cylinder scavenging
B . preheating the combustion chamber
C . reducing air charge density
D . preventing valve wear
-
Scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished()
A . during the valve overlap period
B . with only the exhaust valve open
C . at a pressure below atmospheric
D . without cooling the cylinders or pisto
-
A two-stroke/cycle diesel engine requires less starting air than a four-stroke/cycle diesel engine, of equal displacement, because the two-stroke/cycle diesel engine()
A . has little or no internal friction
B . has a lower effective compression ratio
C . operates with scavenge air under a positive pressure
D . operates without energy absorbing intake and exhaust stroke
-
Clearance volume scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished ().
A . during the valve overlap period
B . with only the exhaust valve open
C . at a pressure below atmospheric
D . without cooling the cylinders or pisto
-
A two-stroke diesel engine exhaust temperature will be lower than a four-stroke diesel engine of the same displacement because the () (1) MEP is lower and the scavenging air is cooling the exhaust gases (2) valve overlap in a four-stroke
A . (1) only is correct
B . (2) only is correct
C . both (1) and (2) are correct
D . Neither (1) or (2) are correct
-
In a four-stroke/cycle diesel engine, badly worn intake valve guides can cause excessive().
A . exhaust pressure
B . exhaust temperatures
C . cooling water temperatures
D . lube oil consumptio
-
Which of the following statements is correct regarding a turbocharged four-stroke/cycle diesel generator?()
A . At zero load the intake manifold pressure is greater than the exhaust manifold pressure
B . At full load the intake manifold pressure and exhaust manifold pressure are equal
C . At full load the intake manifold pressure is less than the exhaust manifold pressure
D . At full load the intake manifold pressure is greater than the exhaust manifold pressure
-
In a closed cooling system for a turbocharged, four-stroke/cycle diesel engine, fluctuating water pressure can be caused by ()
A . improper venting of the cooling system
B . carrying the expansion tank water level too high
C . a totally clogged impeller in the cooling water pump
D . an incorrectly set cooling system temperature control
-
In a four-stroke/cycle diesel engine, after the completion of the power stroke, the piston will move()
A . up and draw in a fresh air charge
B . down to burn off fuel
C . down to compress the fuel air charge
D . up and force out the exhaust gase
-
Which of the following conditions can cause above normal air temperature to develop in the intake manifold of a four-stroke/cycle turbo-charged diesel engine?()
A . Clogged air intake falters
B . Piston blow-by
C . A defective after-cooler
D . Faulty exhaust valve
-
In a four-stroke/cycle diesel engine, the camshaft rotates at ()
A . twice the crankshaft speed
B . half the crankshaft speed
C . the same speed as that of the crankshaft
D . a speed independent of that of the crankshaft
-
For an ordinary four-stroke diesel engine the exhaust valves close ().
A . after TDC
B . before TDC
C . after BDC
D . before BDC
-
A four-stroke cycle, turbocharged, 1000 horsepower diesel engine has been operating under loadThe load suddenly increases, causing excessive black exhaust smoke, and a rapid rise in the lube oil temperatureIn response to this condition, you should:()
A . reduce load
B . check your exhaust
C . adjust cooling water temperature
D . increase lube oil flow
-
Proper lubrication of the main bearing is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because ()
A、a circulating system; a total loss system
B、a total loss system; a circulating system
C、an opened system; a closed system
D、a closed system; an opened system
-
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
-
The reversing cams of some four-stroke/cycle diesel engines are brought into position by ()
A . sliding the camshaft along its axis
B . rotating the cam 180
C . rotating the cam followers 180
D . moving the idler sprockets in the drive chai
-
A disadvantage of a four-stroke/cycle diesel engine is ()
A . higher working temperature of piston and cylinder
B . the use of scavenge ports
C . fewer power strokes per revolution of the crankshaft
D . part of the fuel is burned as the piston is moving away from top dead center
-
In a turbocharged four-stroke/cycle diesel engine, the exhaust valve remains open until after top dead center and the intake valve opens before top dead center to_______.
A.produce a scavenging effect in the combustion space
B.equalize cylinder and exhaust manifold pressures
C.alleviate the difference in valve size between the intake and exhaust
D.flush out condensate that collects after each compression stroke