The turbocharger is used to increase the amount of air that enters the engine's cylinders. This increase of air allows a proportion of fuel to be injected into the cylinders. When an increase of fuel is injected in the cylinders it has the following effects.
| • | Increased power output |
| • | Efficient fuel combustion |
| • | Cooling of the cylinder heads, the pistons, the valves, and the exhaust gas which helps extend the life of the engine. |
Heat energy and pressures in the engine exhaust gas are utilized to drive the turbine wheel. Exhaust gas is directed to the turbocharger housing. The turbocharger housing acts as a nozzle to direct the exhaust gas flow to the turbine wheel blades. The turbine wheel blade drives the shaft wheel assembly. The compressor is attached directly to the shaft. The compressor rotates at the same speed as the turbine wheel. Clean air from the air cleaner is drawn into the compressor housing and the wheel, where is it compressed and delivered through a crossover pipe. This clean air is delivered to the engine air intake manifold and then into the cylinders. The waste-gate valve in the exhaust housing regulates the rise and fall of the air pressure and the air volume delivered to the engine from the compressor outlet.
The position of the waste-gate valve is controlled by the vehicle powertrain control module (PCM) which monitors turbo boost pressure. If increased boost is needed, more pressure is applied to the actuator to close the waste-gate. If less turbo boost is needed, the pressure applied to the actuator will be reduced allowing the waste-gate valve to open, resulting in additional exhaust bypassing the turbine wheel.
