ASVAB Auto and Shop: Engine Systems and Repair 3

Question 1

What does an engine's displacement measurement (e.g., 2.0L) refer to?

Accepted Answer

The total volume swept by all pistons in one complete cycle

Answer

Engine displacement is the total volume swept by all pistons moving from bottom dead center to top dead center in one revolution.

Question 2

A vehicle produces white smoke from the exhaust on a warm day. What does this most likely indicate?

Accepted Answer

Coolant burning in the combustion chamber

Answer

White smoke from the exhaust typically indicates coolant is leaking into the combustion chamber, often due to a blown head gasket.

Question 3

Which of the following best describes valve overlap in an engine?

Accepted Answer

When both intake and exhaust valves are partially open at the same time

Answer

Valve overlap is the brief period at the end of the exhaust stroke and beginning of the intake stroke when both valves are partially open simultaneously.

Question 4

What is the primary purpose of engine oil in a vehicle?

Accepted Answer

Lubricate moving parts to reduce friction and wear

Answer

Engine oil lubricates the moving metal components of the engine to minimize friction, reduce wear, and help dissipate heat.

Question 5

What is detonation (engine knock) in a gasoline engine?

Accepted Answer

Premature ignition of the air-fuel mixture before the spark plug fires

Answer

Detonation (knock) occurs when the air-fuel mixture ignites prematurely or unevenly in the cylinder, causing a characteristic knocking sound.

ASVAB - Armed Services Vocational Aptitude Battery Practice Test

ASVAB - Armed Services Vocational Aptitude Battery Practice Test

ASVAB Auto and Shop: Engine Systems and Repair 3