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Difficulty: MediumFuel and Air Intake Systems

Unlike a mechanical supercharger driven by an engine belt, how does an automotive turbocharger drive its compressor to force air into the intake manifold?

  1. A
    By drawing electrical current directly from the charging alternator
  2. By utilizing expanding exhaust gases to spin a turbine wheelAnswer
  3. C
    By using pressurized coolant circulated from the engine radiator
  4. D
    By drawing mechanical drive directly from the camshaft during the intake stroke

Answer

By utilizing expanding exhaust gases to spin a turbine wheel
An automotive turbocharger harnesses the kinetic and heat energy of hot exhaust gases exiting the engine cylinders. These expanding gases flow through the turbine housing to spin a turbine wheel, which rotates a shared center shaft connected to the compressor wheel in the intake tract, forcing dense, pressurized air into the engine.

Step-by-Step Solution

1
Identify the primary mechanism of forced induction used by a turbocharger.
A turbocharger consists of two main housings: a turbine housing connected to the exhaust manifold and a compressor housing connected to the air intake tract.
Understanding component architecture clarifies how power is transferred from one system to another.
2
Trace the operational energy source that powers the compressor.
Hot, expanding exhaust gases exit the engine cylinders and spin the turbine wheel at high speed, turning a connecting shaft that drives the compressor impeller.
This differentiates a turbocharger (exhaust-driven) from a supercharger (crankshaft belt-driven).
3
Determine the resulting action in the air intake system.
The spinning compressor wheel draws in ambient air, compresses it, and forces dense air through the intake manifold into the combustion chambers.
Increased intake air density allows more fuel to be burned, producing higher engine horsepower.

Key Concept

Turbocharger operation and forced induction via exhaust gas energy
Estimated Time:45s
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Topics

Fuel and Air Intake Systems

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