Copyright by Goodheart-Willcox Co., Inc.
Chapter 16 Turbocharging and Supercharging Systems 329
Turbine
housing
Shaft
Bearing housing
Compressor
housing
Compressor or
impeller wheel
Waste gate
control valve
Waste gate
door
Waste gate
linkage
Exhaust
outlet elbow
Turbine
wheel
Figure 16-2. The basic parts of a turbocharger. (Chrysler)
To vehicle
exhaust
system
Turbine
Turbocharger Compressor
Air
cleaner
Throttle
valve
Increased
pressure
to engine
Engine
exhaust
Engine
Figure 16-3. Turbocharger operation. Exhaust gasses
drive the turbocharger, which compresses the incoming air.
(General Motors)
Turbocharger Construction
Pictured in Figure 16-2, the major parts of a turbo-
charger are:
Turbine housing. The enclosure that routes exhaust
gasses over the turbine wheel.
Turbine wheel. A fan driven by exhaust gasses. It turns
the turbo shaft, which turns the compressor wheel.
Turbo shaft. A steel shaft that connects the turbine
and compressor wheels.
Compressor wheel. A fan that forces air into engine
intake manifold under pressure. It is driven by the
turbo shaft.
Compressor housing. The enclosure that surrounds
the compressor wheel. Its shape helps pump air into
the engine.
Bearing housing. The enclosure around the turbo
shaft that contains bearings, seals, and oil passages.
Turbocharger Operation
During engine operation, hot exhaust gasses blow out
of the open exhaust valves and into the exhaust manifold,
Figure 16-3. The exhaust manifold and connecting tubing
route these gasses into the turbine housing. As the gasses
pass through the turbine housing, they strike the fins or
blades on the turbine wheel. When engine load is high
enough, there is enough exhaust gas flow to rapidly spin
the turbine wheel.
Since the turbine wheel is connected to the compres-
sor wheel by the turbo shaft, the compressor wheel rotates
with the turbine. Compressor wheel rotation pulls air into
the compressor housing. Centrifugal force throws the air
outward. This causes air to flow out of the turbocharger
and into the engine cylinder under pressure. With more air
and fuel in the cylinder on the engine’s intake stroke, more
pressure and combustion force result during the engine’s
power stroke.