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WorksheetsCamshaft and Valve Operation Quiz chapter 32
Total questions: 29
Worksheet time: 19mins
Camshafts turn at which of these?
Twice crankshaft speed
Crankshaft speed
1/2 crankshaft speed
1/4 crankshaft speed
Flat-bottom valve lifters rotate during operation because of the ________ of the camshaft.
taper of the lobe
thrust plate
chain tensioner
bearings
A DOHC V-6 has how many camshafts?
4
3
2
1
On a vehicle with cylinder deactivation, the valves are kept closed by deactivating the ________.
valve lifter
cam lobe
valve stem
valve spring
The maximum total indicator runout (TIR) of a camshaft should be less than ________.
0.002 in.
0.006 in.
0.004 in.
0.008 in.
Many technicians always use new pushrods because ________.
they are less expensive to buy than clean
all dirt cannot be cleaned out from the hollow center
they wear at both ends
pushrods shrink in length if removed from an engine
If the exhaust valve opens at 57° BBDC (before bottom dead center) and closes at 29° after TDC (top dead center), what is the exhaust valve duration in degrees?
86
209
237
266
Variable cam timing technology is used on the exhaust cam only.
True
False
The intake valve opens at 39° BTDC (before top dead center) and closes at 71° ABDC (After bottom dead center). The exhaust valve opens at 78° BBDC (before bottom dead center) and closes at 47° ATDC (after top dead center). Which of these is correct regarding this cam timing?
Intake valve duration is 110°
Exhaust valve duration is 125°
Overlap is 86°
Both A and B
Hydraulic lifters or hydraulic lash adjusters (HLA) may not bleed down properly and could cause an engine miss if ________.
the engine oil is 1 quart low
the wrong API-rated engine oil is used
the wrong SAE-rated engine oil is used
both A and B
On an engine with variable cam timing, the cam timing can be changed by use of ________.
a spline cam phaser
a vane cam phaser
either of these
neither of these
The valves could be bent if the timing belt breaks on which of these?
Freewheeling engine design
In-block cam engine
Interference engine design
Undersquared engine
A cylinder deactivation system uses ________ to operate the system.
magnetic induction
oil pressure
roller pumps
none of these
The camshaft makes ________ for every revolution of the crankshaft.
one quarter revolution
one half revolution
one revolution
two revolutions
Which term is used to describe the number of degrees of crankshaft rotation for which the valve is lifted off the seat?
Duration
Lift
Overlap
Underlap
Technician A says that silent chains are quieter than roller chains and do not stretch with use. Technician B says that on overhead valve engines, the camshaft is usually placed in the block above the crankshaft. Who is right?
Technician A only
Technician B only
Both technicians
Neither technician
Two technicians are discussing an engine with an interference design. Technician A says if a valve remains open when its cylinder reaches TDC, the piston may strike the valve. Technician B says if a valve remains open when its cylinder reaches TDC, valvetrain damage can result. Which technician is correct?
Technician A only
Technician B only
Both technicians
Neither technician
What is the primary purpose of a turbocharger in an engine?
To increase fuel efficiency by reducing engine size
To reduce emissions by controlling exhaust flow
To increase engine power by forcing more air into the combustion chamber
To cool the engine by circulating extra air
What is the main advantage of using an Engine Control Unit (ECU) in modern vehicles?
It allows for manual control of the engine's functions
It increases the vehicle's top speed
It optimizes engine performance and fuel efficiency
It reduces the need for regular maintenance
What is the effect of a fouled spark plug on engine performance?
It improves engine performance
It has no effect
It can cause the engine to run rough or misfire
It increases the engine's horsepower
What is the primary function of a fuel injection system in an automotive engine?
To lubricate the engine's moving parts
To cool the engine
To mix fuel with air to produce a combustible mixture
To filter impurities from the fuel
Which component of the engine management system is primarily responsible for controlling fuel injection timing and quantity?
Oxygen sensor
Engine Control Unit (ECU)
Throttle body
Fuel pump
How does an Engine Control Unit (ECU) adjust ignition timing based on driving conditions?
By changing the fuel type used in the engine
By mechanically adjusting the distributor
By altering the spark plug gap
By processing data from various sensors and adjusting the timing electronically
Ignition timing is crucial for engine performance. What happens if the ignition timing is too advanced?
The engine will not start
It can cause knocking or pinging
The engine will overcool
Fuel consumption will decrease significantly
What distinguishes Direct Injection from Port Injection in fuel delivery systems?
Direct Injection delivers fuel directly into the combustion chamber, while Port Injection delivers it into the intake manifold
Port Injection is more fuel-efficient than Direct Injection
Direct Injection is only used in diesel engines
Port Injection uses higher pressure than Direct Injection
Why is it important for an Engine Control Unit (ECU) to monitor and adjust the air-to-fuel ratio?
To ensure the vehicle can reach maximum speeds
To maintain optimal engine temperature
To optimize engine performance and fuel efficiency
To increase the loudness of the exhaust system
What is a chassis?
The axis on which a wheel spins
The frame or structure of a vehicle
A special science formula
Which type of fuel injection system uses a common rail to supply fuel to the injectors?
Direct Injection
Port Injection
Sequential Fuel Injection
Common Rail Direct Injection (CRDI)
What is a wheel with a groove down the center called?
gear
pulley
lever
screw
