Turbocharger — operating principle (Peugeot 605)

The diesel vehicles listed in this manual are equipped with an exhaust-driven turbocharger. The turbocharger has two turbine wheels mounted on a single shaft, housed in housings separated from each other. The wheels are driven by the exhaust gases. They increase the compressor shaft speed to 120,000 rpm. Since the exhaust-driven rotor and the fresh air intake rotor are mounted on the same shaft, atmospheric air is forced into the combustion chambers of the cylinders at the same speed.

Due to the good filling factor, a power increase of up to 100% can be achieved in existing engines. Depending on the engine type, the use of a turbocharger also increases the torque. The degree of this increase depends, among other things, on the boost pressure, which in a passenger car is between 0.4 and 0.8 bar. The boost pressure can be controlled and regulated by the engine control unit via a solenoid valve, or the air can be injected only via a pressure reducing valve.

Between the turbocharger and the air intake, there may be a boost air cooling radiator that reduces the temperature of the air compressed by the compressor. This increases engine power because the cooled air has a higher oxygen content due to its higher density.

In contrast to the internal combustion engine, turbocharged diesel vehicles do not need to reduce normal compression, allowing full use of the injected fuel even in the low engine speed range.

The turbocharger is an extremely precisely manufactured unit. As a rule, in case of failure, the turbocharger is replaced completely.