Unit 2- Chapter 44

Front 1

The cause of parasitic loss in an engine:

Back 1

Friction

Front 2

To manually perform a cylinder power balance test, one should:

Back 2

unplug individual fuel injectors.

Front 3

Whirring noise is likely to be from external accessories such as:

Back 3

alternators, water pumps, and belt tensioners.

Front 4

The component that is responsible for opening the valves at the right time is called the:

Back 4

camshaft.

Front 5

The amount of slack between the rocker arm or cam follower and the valve stem, or the cam and the lifter if it is a bucket-style OHC engine:

Back 5

Valve clearance.

Front 6

OHC engine stands for:

Back 6

Over Head Cam

Front 7

In variable valve timing engines, the cam phaser is controlled by:

Back 7

the power train control module.

Front 8

Technician A says that in a performance engine, large valve overlap and lift increase high-end rpm. Technician B says that low-end power is sacrificed as a result of large valve overlap. Who is correct?

Back 8

Both Tech A and B.

Front 9

Technician A says that one job of the piston rings is to prevent blow-by. Technician B says that oil control piston rings help to allow oil into the combustion chamber to mix with the air–fuel mixture. Who is correct?

Back 9

Tech A

Front 10

Technician A says that parasitic loss in an engine is caused by low fuel volatility. Technician B says that parasitic loss is caused by internal component friction. Who is correct?

Back 10

Tech B

Front 11

A diesel engine is an example of a ______________ engine.

Back 11

Compression ignition

Front 12

A gasoline engine is an example of a ______________ engine.

Back 12

Spark ignition

Front 13

When force causes movement, _______ is done.

Back 13

work

Front 14

Which color of smoke from the exhaust does NOT indicate an internal mechanical problem in the engine?

Back 14

Black

Front 15

When diagnosing engine noise, Technician A says a mechanical stethoscope may not be appropriate in pinpointing a squeaking drive belt. Technician B says a whirring noise is likely to be from external accessories such as alternators, water pumps and belt tensioners. Who is correct?

Back 15

Both Tech A and B

Front 16

The amount of slack between the rocker arm or cam follower and the valve stem is known as valve:

Back 16

camshaft

Front 17

Technician A says that piston clearance is necessary for lubrication between the piston and the cylinder wall. Technician B says that piston clearance is necessary for piston expansion due to heat. Who is correct?

Back 17

Both Tech A and B

Front 18

Both steam engines and Stirling engines are known as ______________ combustion engines.

Back 18

External

Front 19

Effort to produce a push or pull action is called:

Back 19

Force

Front 20

Technician A says that movement does not have to occur to have torque. Technician B says that torque is a twisting force. Who is correct?

Back 20

Both Tech A and B

Front 21

The percentage at which a cylinder is filled with air when it is running is known as:

Back 21

volumetric efficiency.

Front 22

An engine's vacuum is being tested with a gauge. When the throttle is snapped wide open momentarily, the gauge drops to zero and then reaches a high of 20 inches. Technician A says this could indicate worn piston rings. Technician B says the reading should have reached about 27 inches. Who is correct?

Back 22

Both Tech A and B

Front 23

How even should the cranking compression be between the lowest and highest cylinder readings on an engine without mechanical problems?

Back 23

Within 10% to 15%

Front 24

When the throttle is snapped wide open during a running compression test, what reading should be seen for a normal cylinder?

Back 24

About 80% of the cranking compression pressure

Front 25

A gas that will not react chemically:

Back 25

inert gas

Front 26

The amount of time the valve stays open, given in the degrees of rotation of the crankshaft:

Back 26

duration

Front 27

The rise of the lobe from the base circle to the top of the love, which is where the valve starts to lift, on the side opposite of where it starts to close:

Back 27

cam lobe ramp

Front 28

An engine cycle that uses a longer exhaust stroke than intake stroke through delayed closing of the intake valve. This Engine uses a supercharger to pressurize air into the cylinder when needed.

Back 28

Miller Cycle

Front 29

The mixture of materials to make a substance that has properties different from the original materials. Aluminum alloy has silica added to make it perform better than pure aluminum.

Back 29

Alloy

Front 30

Locking devices that keep the valve retained by the valve spring seat.

Back 30

keepers

Front 31

The amount the valve will open. The more the valve lifts off its seat, the more air can get into and out of the engine.

Back 31

Lift

Front 32

A flexible valve made from spring steel that flexes to open or close, usually due to pressure changes.

Back 32

Reed Valve

Front 33

THe rounded bottom part of the camshaft (off the lobe) where the valves remain closed or at rest.

Back 33

Base Circle

Front 34

A device that transfers motion from the cam lobe to a pushrod or directly acts on the valve and spring, depending on if the cam is in the engine block or the cylinder head; sometimes called a tappet.

Back 34

Valve Lifter

Front 35

The area below the ring groove area of the piston that prevents the piston from cocking and becoming jammed in the cylinder bore.

Back 35

Piston Skirt

Front 36

The process of removing burned gases from the cylinder through the use of moving airflow pulling or extracting the gases out.

Back 36

Scavenging

Front 37

Tech A says that engines using compression ignition control timing by regulating when fuel is injected into the cylinder. Tech B Says that engines using spark ignition control timing by regulating when fuel is injected into the cylinder. Who is correct?

Back 37

Tech A

Front 38

Tech A says that horsepower is a measurement of the amount of work being performed. Tech B says that horsepower can be calculated by multiplying torque by rpm and dividing by 5252. Who is correct?

Back 38

Tech B

Front 39

Tech A says that in a four-stroke engine, the piston is at TDC four times to complete the cycle. Tech B says that the air/fuel mixture is ignited once every two strokes Who is correct?

Front 40

Tech A says that spark ignition typically occurs before TDC. Tech B says that spark ignition typically occurs after TDC. Who is correct?

Front 41

Tech A says that valve overlap occurs between the exhaust stroke and the intake stroke. Tech B says that valve overlap occurs to assist in scavenging the cylinder. Who is correct?

Front 42

Tech A says that compression ratio is the comparison of the volume above the piston at BDC to the volume above the piston at TDC. Tech B says that scavenging of the exhaust gases occurs once the exhaust valve closes. Who is correct?

Front 43

Tech A says that the weight o the flywheel smooths out the engine's power pulses. Tech B says that the flex plate and torque converter perform the same function as the flywheel. Who is correct?

Front 44

Tech A says that an interference engine is designed so that the pistons can hit the valves if the timing belt breaks. Tech B says that the shape of the cam lobe determines how long and far the valves are held open. Who is correct?

Front 45

Tech A says that blow-by gases occur when compression and combustion gases leak past the piston rings. Tech B says that a rotary engine uses reed valves to control air flow into the cylinder on intake. Who is correct?

Front 46

Tech A says that the principle of thermal expansion is what pushes the piston down the cylinder on the power stroke. Tech B says that the piston is pulled down the cylinder on the intake stroke. Who is correct?

Front 47

What does TDC stand for?

Back 47

Top Dead Center

Front 48

What does BDC stand for?

Back 48

Bottom Dead Center