Which energy source powers a turbocharger rather than a mechanically driven supercharger?

• A. Electrical power from the alternator.
• B. Hydraulics from the engine.
• C. Vacuum from the intake manifold.
• D. Exhaust gas energy directing a turbine.

Answer: (D)

Turbochargers use energy from the exhaust stream to drive a turbine. The hot, high-energy exhaust gases leaving the engine pass through a turbine wheel, transferring their energy to spin the turbine. This turbine is connected by a shaft to a compressor that then forces more air into the engine, increasing intake density and boosting power. This method reclaims energy that would otherwise be wasted in the exhaust. A mechanically driven supercharger, on the other hand, is powered directly by the crankshaft via belts or gears, drawing energy from the engine to drive the compressor, which is less efficient overall. While electric or hydraulic systems can power alternative turbo setups in some designs, in standard practice the turbo’s energy source is exhaust gas energy directing a turbine. Vacuum from the intake manifold isn’t what drives the turbine itself, though it may act on other components in some systems.