Turbocharger

The diesel engine is equipped with a turbocharger. In the turbocharger, two turbine wheels sit on one shaft and are housed in two separate housings.

The turbine wheels are driven by the exhaust gases that are already present. They spin the charger shaft at over 120,000 rpm. Since the exhaust-side and intake-side rotors sit on the same shaft, fresh air is forced into the cylinders at the same speed. The precompressed, heated air is cooled in an intercooler, which further improves the charge density.

Due to the good charge density, power increases of up to 100 percent can be achieved on existing engines. The power increase depends, among other things, on the boost pressure, which in a passenger car engine is between 0.4 and 0.8 bar (tire inflation pressure approx. 1.8 bar). If the boost pressure rises above the value set at the factory, the wastegate valve opens and the pressure can escape.

In addition to engine output, using an exhaust turbocharger also increases torque, which is especially desirable for smooth engine operation. Compared with a gasoline engine, a diesel engine does not require reducing the normal compression ratio because of the boost, so the injected fuel is fully utilized even in the low speed range.

The turbocharger is an extremely precisely manufactured component.

It is therefore advisable to have repairs carried out only by a specialist. As a rule, a faulty turbocharger is replaced completely.

The exhaust turbocharger is supplied with oil from the engine oil circuit.

To ensure adequate lubrication of the charger, the following points must be observed:

• Use only the specified engine oil.

• Over-aged engine oil can cause the charger to coke. Engine oil and oil filter must therefore be changed strictly according to the maintenance schedule.

• Since even the smallest dirt particles can destroy the turbocharger, never run the engine without the air filter.