ASVAB Automotive Information Practice Test 74766 Results

Your Results Global Average
Questions 5 5
Correct 0 2.74
Score 0% 55%

Review

1

The distributor is responsible for:

71% Answer Correctly

distributing power to the correct drive wheels

timing the spark and distributing it to the correct cylinder

recharging the battery

utlizing battery power to start the engine


Solution

The distributor is driven by the engine's camshaft and is responsible for timing the spark and distributing it to the correct cylinder. The distributor cap contains a rotor that connects the ignition coil (and its high voltage) to the proper cylinder at the proper point in the stroke cycle.


2

Which of the following is not a function of antifreeze?

54% Answer Correctly

raises the boiling point of water

keeps water from freezing at low temperatures

lubricates the cooling system

aids heat transfer


Solution

Modern car engines are cooled by liquid which circulates through the engine block and cylinder heads absorbing excess heat. This liquid is made up of half water and half antifreeze (commonly, ethylene glycol) which both keeps the water from freezing at low temperatures and raises its boiling point making heat transfer more efficient.


3

Opposed cylinder designs feature two rows of cylinders that are placed at what angle to each other?

49% Answer Correctly

270°

90°

45°

180°


Solution

Opposed cylinder designs place cylinders flat in two rows 180° opposite each other with a single crankshaft running between them.


4

Which of the following is not an advantage that disc brakes have over drum brakes?

50% Answer Correctly

are more easily cooled

provide a larger contact area

provide more braking force

use less brake fluid


Solution

Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled.


5

Which of the following is the result of combustion being initiated by a source other than the spark plug?

51% Answer Correctly

pre-ignition

detonation

ignition

pre-combustion


Solution

Normal combustion in an engine is initiated by a spark plug and results in the complete burning of the air-fuel mixture. If combustion is initiated by a source other than the spark plug, by a hot spot in the cylinder or combustion chamber for example, pre-ignition results. Detonation results if the air-fuel mixture explodes instead of burning. Detonation can cause extremes in pressure in the combustion chamber leading to engine damage.