ASVAB Automotive Information Practice Test 137657 Results

Your Results Global Average
Questions 5 5
Correct 0 2.94
Score 0% 59%

Review

1

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

65% Answer Correctly

has an odd number of cylinders

has two rows of cylinders

common in motorcycles, cars, and trucks

engine is shorter than an inline engine


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

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

66% Answer Correctly

4-3-2-1

3-1-2-4

1-3-4-2

1-2-3-4


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.


3

Just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. This describes which engine stroke?

61% Answer Correctly

power

compression

intake

exhaust


Solution

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.


4

The fuel pressure regulator ensures that the fuel injectors receive fuel at a consistent and known rate. The fuel pressure regulator is part of the:

40% Answer Correctly

fuel rail

fuel manifold

fuel filter

electric fuel pump


Solution

The electric fuel pump feeds pressurized fuel through a fuel filter to the fuel injectors via the fuel rail manifold. The fuel rail contains the fuel pressure regulator which ensures that the fuel injectors receive fuel at a consistent and known rate. Excess fuel bled off by the pressure regulator returns to the fuel tank through the fuel return line.


5

What is the name of the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air?

62% Answer Correctly

combustion ratio

stoichiometric ratio

ignition ratio

residual ratio


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.