BMW diesel engine equipped with a turbocharger (turbocharger). It has two turbine wheels on one shaft, which are located in housings separated from each other. The exhaust gases of the engine are used to drive the turbine wheels. They accelerate the turbocharger shaft to 120,000 rpm. As turbine wheels for exhaust gases and for fresh (outdoor) air sit on the same shaft, then fresh air is injected into the cylinders at the same speed.
Due to the good filling of the cylinders in the described engines, the increase in power can reach up to 10%. Among other things, the increase in power depends on the boost pressure, which in passenger car engines ranges from 0.4 to 0.8 bar. If the boost pressure exceeds a certain value, the damper control valve opens and the pressure decreases.
When using a turbocharger, in addition to engine power, torque also increases, which, above all, is the desired result in terms of engine flexibility. Unlike a gasoline engine, a diesel engine does not need to reduce the normal compression ratio due to boost, so that the injected fuel is fully utilized in the lower rev range.
The turbocharger is a precision manufactured part. For this reason, it is recommended that repairs be carried out only in a workshop or by a qualified specialist. As a rule, if damaged, the turbocharger is completely replaced.
The turbocharger is provided with oil from the engine lubrication system. To ensure proper lubrication of the compressor, the following rules must be observed: Use only the engine oil specified in the instruction manual.
Due to the use of old oil, the turbocharger can coke. For this reason, the oil and oil filter must be changed strictly at the specified time.
Since even very small dirt particles can cause turbocharger failure, never run the engine without an air filter.