Turbo Pressure Control

Turbo Pressure Control












The turbo pressure in the intake manifold depends mainly on engine speed and load. At higher loads, however, turbo pressure is restricted by the wastegate.

The wastegate is a flap valve which closes or opens the "bypass" channel at the side of the turbine.

The flap valve is actuated by a solenoid valve and a diaphragm box. The diaphragm box is actuated by the turbocharger pressure and a spring in it closes the flap valve via a rod.

The solenoid valve controls the flow of air past the wastegate, having regard to the air mass/combustion ratio, so that it is always in keeping with what is requested.

At low and normal loads the wastegate for turbo pressure is closed. When the load increases and turbo pressure approaches maximum, the spring force is overcome and the valve opens the "bypass" channel, thus reducing the pressure.

The pressure is monitored continuously by a pressure sensor connected to the intake manifold by a hose.

The light turbo variant (B204E) has a control valve that opens at a predetermined pressure (0,45 bar), without being controlled by Trionic.

For further information on turbo control and the solenoid valve, see Air Bypass Valve.

Turbo Pressure Control (B235R)







The turbo pressure in the intake manifold depends mainly on engine speed and load. At higher loads, however, turbo pressure is restricted by the wastegate.

The wastegate is a flap valve that opens or closes the bypass past the turbine.

The flap valve is acted on by a diaphragm box located by the turbocharger housing. The diaphragm box is acted on by the turbocharger pressure and a spring in the diaphragm box closes the flap valve via a rod.

The diaphragm box is controlled by the solenoid valve. The solenoid valve controls the flow of air past the wastegate, having regard to the air mass/combustion ratio, so that it is always in keeping with what is requested.

Under low or normal loads, the wastegate is closed. When the load increases and turbocharger pressure approaches the highest permitted value, the force of the spring is overcome and the valve opens the "bypass", reducing the turbine speed and lowering the pressure.

The pressure is monitored continuously by a pressure sensor connected to the intake manifold by a hose.

For further information concerning turbo control and the solenoid valve, see Air Bypass Valve, Trionic T7.