ASVAB Automotive Information Practice Test 797559 Results

Your Results Global Average
Questions 5 5
Correct 0 2.85
Score 0% 57%

Review

1

How are the cylinders numbered in V-type engines?

42% Answer Correctly

cylinder numbering varies by manufacturer

alternating from the front of the engine to the back

sequentially from the back of the engine to the front

sequentially from the front of the engine to the back


Solution

In V-type engines the numbering sequence varies by manufacturer.


2

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

50% Answer Correctly

use less brake fluid

provide more braking force

are more easily cooled

provide a larger contact area


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.


3

The stoichiometric ratio is approximately:

70% Answer Correctly

1:1

14.7:1

1:14.7

14.7


Solution

The stoichiometric ratio defines the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air. For gasoline fuel, the stoichiometric ratio is about 14.7:1 or for every one gram of fuel, 14.7 grams of air are required. Too much air results in a lean air-fuel mixture that burns more slowly and hotter while too much fuel results in a rich mixture that burns quicker and cooler.


4

Which of the following is not a characteristic of disc brakes?

57% Answer Correctly

uses brake shoes

newer brake system

uses brake pads

uses a rotor


Solution

Both drum brake and disc brake assemblies use friction to stop a car's wheels from turning but each do it in a slightly different way. A drum brake assembly uses a large iron drum attached to the wheel and brake shoes that press against the drum to slow the rotation of the drum and, consequently, the wheel. A disc brake assembly employs friction in the same way as a drum brake but instead uses a rotor, also attached to the wheel, and two brake pads that squeeze against the surface of the rotor.


5

Which of the following is a common firing order for four-cylinder engines?

66% Answer Correctly

1-2-3-4

4-3-2-1

3-1-2-4

1-3-4-2


Solution

The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together.