Turbocharger - Overview. Description and Operation

Overview

NOTICE: Whenever turbocharger intake system components are removed, always cover open ports to protect against debris. It is important to prevent foreign material from entering the system. The turbocharger compressor wheel blades are susceptible to damage from even small particles. All components must be inspected and cleaned, if necessary, before installation or reassembly.

The turbocharger is an exhaust-driven centrifugal air compressor. Its purpose is to increase engine output by delivering compressed air to the engine. Internal components are cooled by engine oil, engine coolant and air. Engine oil and coolant circulate through the center housing, which acts as a thermal barrier between the "hot" turbine and the "cold" compressor. The journal bearings are lubricated by engine oil. Oil circulates to the turbocharger center housing and returns to the oil pan through the oil drain in the center housing.

Expanding exhaust gases accelerate the turbine shaft assembly to speeds of up to 200,000 rpm. Filtered air entering the compressor side of the turbocharger is compressed and delivered through the Charge Air Cooler (CAC). The very hot compressed air is cooled by the CAC, then continues to fill the intake manifold at a pressure higher than atmospheric pressure. Because significantly more air is forced into the intake manifold, the result is increased power, fuel economy and the ability to maintain power at high altitudes.