The principle of operation of a gas turbine supercharger

The diesel engine of the bus is equipped with a turbocharger. Two turbine wheels of the turbocharger are mounted on one shaft, placed in two casings separated from each other. Turbine wheels are driven by exhaust gases. They spin the supercharger shaft up to 120,000 rpm. And since the turbine rotor and the supply air rotor sit on the same shaft, air is also supplied to the cylinders with the same number of revolutions.

Thanks to dense filling, it is possible to increase the power of existing types of motors up to 100%. The increase in power depends, among other things, on the boost pressure, which lies between 0.4 and 0.8 bar (tire pressure is about 1.8 bar). Normally the boost pressure is higher than the factory setting, the exhaust valve opens and the pressure is reduced.

Along with an increase in engine power, when using a turbocharger, the torque also increases, which is desirable from the point of view of the elasticity of the engine. The prerequisite for this is, of course, that the motor shaft rotates at a sufficient speed to guarantee a sufficiently dense filling. As a general rule, to achieve sufficient boost pressure, the engine must rotate at a speed of about 3000 rpm.

Compared to an Otto engine, a supercharged diesel requires a reduction in the normal compression ratio, so even at these speeds full use of fuel injection is ensured.

The turbocharger is an extremely precisely manufactured device. Therefore, it is recommended that only a specialist repair it. As a rule, in the event of a defect, the turbocharger is replaced completely.