Turbocharger operation
The exhaust gases, which are still at a rather high temperature, are led to the turbine wheel, causing the wheel to rotate. When the turbine rotates, the gases expand and transfer to the shaft of the unit the excess power consumed to compress the air in the compressor located on a common shaft with the turbine. The rotational speed of the turbocharger shaft varies in the range of 20,000-115,000 rpm, which is accompanied by a characteristic "whistling" turbines.
Gas bypass valve past the turbine
If the pressure of the air supplied by the compressor exceeds the allowable (in terms of engine reliability), exhaust gases are bypassed past the turbine by a special valve with an autonomous drive. The drive is a diaphragm driven by charge air pressure. In this way, feedback control of the boost pressure is carried out.