1. Boost pressure limit control

The engine control unit controls the pulse width of the boost pressure limit solenoid valve according to the current engine speed and load requirements, so that part of the exhaust gas is discharged from the exhaust bypass valve, and regulates the amount of exhaust gas flowing through the turbine, so as to effectively control the intake boost pressure and adapt it to the engine working conditions.

2. Charge air circulation control

When the boost pressure rises sharply due to sudden changes in engine working conditions or other factors, such as sudden acceleration and sudden loss of throttle, the engine control unit controls the charge air recirculation solenoid valve to make the gas in front of and behind the supercharger conduct and maintain pressure balance. This control can effectively avoid gas noise and impeller damage when the throttle is closed, and can keep the turbocharger at a higher speed, so that the turbocharger can provide the required boost pressure to the engine more quickly when needed, and reduce the "hysteresis" phenomenon of the turbocharger.

3. Supercharger cooling system control

The heat accumulation of turbochargers is relatively serious because they are exposed to high temperature for a long time. After the engine stops working, its mechanical water pump stops working. At this time, in order to effectively protect the supercharger, additional cooling is required for the supercharger. Therefore, the exhaust gas turbocharging system generally has the delayed shutdown function of the electronic water pump, that is, after the engine stops working, the electronic water pump continues to run for a period of time (such as 8 min), so as to ensure the heat dissipation of the turbocharger and implement protection.