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Failure of fuel injection is usually due to trouble in the ().
A . exhaust valves
B . mechanical lubricators
C . cooling water pumps
D . fuel injection pum
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If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will()
A . backfire through the air intakes
B . develop less power under load
C . have high firing pressures
D . lift its cylinder relief valve
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The amount of fuel injected in a particular time, or degree, of crankshaft rotation is termed ().
A . metering
B . timing
C . rate of injection
D . rate of distributio
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The effective pump stroke of an individual port-and-helix fuel injection pump is determined by the ()
A . fuel delivery pressure
B . pump plunger diameter
C . plunger control rack position
D . total pump stroke
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In a diesel engine, when the fuel is injected into the cylinder,()
A . the piston is just coming upward from the bottom dead center
B . the piston has moved about one-fifth of the way up
C . the piston has moved most of the way up and almost reached the TDC
D . the piston has just past the TDC
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When a fuel injection nozzle overheats, which of the problems listed can be expected?()
A . The fuel metering will vary
B . The fuel will explode
C . The cylinder head will crack
D . The engine will sto
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Late fuel injection timing is indicated by ()
A . lower than normal cylinder pressure and low exhaust temperature
B . lower than normal cylinder pressure and high exhaust temperature
C . higher than normal cylinder pressure and low exhaust temperature
D . higher than normal cylinder pressure and high exhaust temperature
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In a common rail engine, the fuel is injected into cylinders()
A . by injection pumps
B . at a time decided by the injection pump timing
C . by a signal opening the magnetic valves
D . at a time decided by the cam directly
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Which of the following problems may occur if the opening pressure of a fuel injection nozzle is greater than specified by the engine manufacturer?()
A . The amount of fuel injected will be increased
B . The start of injection will be retarded
C . The nozzle will permit fuel to dribble
D . The spray pattern will be distorted
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Fuels of different qualities may require advancing or retarding the injection timing, in addition to which if the injection timing is advanced when the engine is running at loads below the (), then a saving in fuel can be achieved.
A . BHP
B . MCR
C . IHP
D . MEP
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The sequence of fuel injection into cylinders is determined by ().
A . the steering
B . the driven gear
C . the turning gear
D . the timing gear
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When ship is fouled, increasing the fuel injection for keeping the normal speed will cause the main engine ()
A . to work as overload characteristic
B . overspeed
C . over mechanical load only
D . over thermal load only
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It should be evident that the amount of fuel injected into the cylinder is dependent on the position of the helix relative to the ().
A . inlet port
B . exhaust port
C . spill port
D . scavenge port
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The major cause of fuel pump and injection system problems is ()
A . improper adjustments
B . contaminated fuel
C . kinked fuel lines
D . excessive engine vibratio
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A diesel engine will lose power if fuel injection occurs too late in the cycle, because the()
A . fuel droplets will burn as they leave the fuel injector
B . fuel will not be properly atomized in the cylinder
C . maximum expansion of the burned fuel cannot take place in the cylinder
D . compression pressure will be too low to cause fuel ignitio
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Modern marine diesel engines using mechanical fuel injection, operate on a combustion cycle which is()
A . a combination of constant volume and constant pressure
B . a combination of constant temperature and constant pressure
C . entirely constant pressure
D . entirely constant volume
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A practical way of checking for excessive fuel injection in one cylinder of an operating diesel engine is to ()
A . feel the high pressure fuel line
B . check the cylinder exhausts for white smoke frequently
C . check the cylinder exhaust temperature
D . isolate each cylinder and inspect the injector
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Generally speaking,the fuel injected into a marine diesel engine combustion chamber is ignited by().
A . spark plugs
B . glow plugs
C . heat of compression
D . a magneto
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If keep the fuel injection of main engine unchanged when ship is fouled, that will causeⅠ.The speed of main engine to be reduced Ⅱ.Ship speed to be reduced Ⅲ.The resistance torque of propeller to be increased Ⅳ.Trim at stern to increase()
A . Ⅰ + Ⅱ
B . Ⅰ ~ Ⅲ
C . Ⅰ ~ Ⅳ
D . Ⅰ + Ⅱ + Ⅳ
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The amount of fuel injection into a diesel engine cylinder by a unit injector, is controlled by()
A . the firing pressure in the cylinder
B . a metering helix inside the pump
C . varying the physical length of the plunger stroke
D . varying the clearance between the injector cam and the injector rocker arm
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Early fuel injection timing is indicated by the cylinder pressure being()
A . above normal with a below normal exhaust temperature
B . above normal with a normal exhaust temperature
C . below normal with a normal exhaust temperature
D . below normal with an above normal exhaust temperature
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The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to ().
A . assist in a quick cutoff of fuel injection
B . allow oil backflow from the injector to the helix
C . reduce fuel oil pressure between injection strokes
D . meter the quantity of fuel delivered
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Fuel injection uses the jet pump system and a Woodward type hydraulic () is used to control engine speed.
A . controller
B . governor
C . instrument
D . apparatu
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Late fuel injection in a diesel engine is indicated by low firing pressure with()
A . high exhaust temperature
B . low exhaust temperature
C . fuel knock in each cylinder
D . mechanical knock in each cylinder