ASVAB Automotive Information Practice Test 632460 Results

Your Results Global Average
Questions 5 5
Correct 0 3.20
Score 0% 64%

Review

1

Which of the following statements about v-type cyllinder arrangement is false?

65% Answer Correctly

has two rows of cylinders

common in motorcycles, cars, and trucks

engine is shorter than an inline engine

has an odd number of cylinders


Solution

A v-arrangement has two rows of cylinders in a V-shaped block with a crankshaft at the bottom of the V. Any even number of cylinders is possible in this configuration from the V-2 that's commonly used in motorcycles up to V-12 or bigger for large trucks. The V design produces a shorter engine than an in-line cylinder configuration and allows for better air-fuel distribution.


2

Engine oil viscosity is rated using the format XW-XX with the number preceding the W indicating viscosity at __________ ℉ and the XX indicating viscosity at __________ ℃.

65% Answer Correctly

100, 0

0, 0

0, 100

100, 100


Solution

The primary component of the lubrication system is engine oil. Engines require oil blends with different thickness (viscosity) and additives depending on their operating conditions. Viscosity is rated using the format XW-XX with the number preceding the W (winter) rating the oil’s viscosity at 0 ℉ (-17.8 ℃) and the XX indicating viscosity at 100 ℃.


3

Which engine stroke starts with the piston at top dead center?

61% Answer Correctly

power stroke

exhaust stroke

intake stroke

compression stroke


Solution

The four-stroke piston cycle of internal combustion engines starts with the piston at top of the cylinder head (top dead center or TDC) during the intake stroke. The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber through the now open intake valve.


4

The stoichiometric ratio is approximately:

70% Answer Correctly

14.7

1:14.7

1:1

14.7:1


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.


5

Ignition timing is measured in number of degrees:

59% Answer Correctly

before bottom dead center

before top dead center

after bottom dead center

after top dead center


Solution

Ignition timing defines the point in time at the end of the compression stroke that the spark plug fires. Measured in number of degrees before top dead center (BTDC), the exact point that the spark plugs initiate combustion varies depending on the speed of the engine. The timing is advanced (the spark plugs fire a few more degrees BTDC) when the engine is running faster and retarded when it's running slower.