What powers the turbine in a turbocharger?

• A. Exhaust gas flowing from the engine.
• B. Crankshaft-driven belt.
• C. An electric motor powered by the battery.
• D. Ambient air pressure.

Answer: (A)

The turbine in a turbocharger is driven by the energy in the exhaust gas. When fuel is burned, the hot, high-velocity exhaust gases flow through the turbine wheel inside the turbocharger, causing it to spin. This turbine is connected on the same shaft to the compressor wheel; as the turbine turns, it drives the compressor, which draws in and compresses intake air, increasing engine air density and allowing more fuel to be burned for more power. This design uses energy that would otherwise be wasted in the exhaust to boost performance. The other options don’t fit because a belt would drive a supercharger, not the turbocharger turbine; an electric motor would be for an electrically driven assist unit rather than the turbine’s primary source in a traditional setup; and ambient air pressure isn’t what powers the turbine.