Turbocharger (TC) control valve

The boost pressure control (BPC) valve is controlled by boost pressure via the turbocharger (TC) control valve (6). An output on the engine control module (ECM) (7) transmits a pulsed signal to the turbocharger (TC) control valve. By altering the signal duty cycle (the pulsing signal) the pressure to the boost pressure control (BPC) valve can be controlled. When the engine control module (ECM) determines that a higher boost pressure is permissible, the duty cycle of the signal to the turbocharger (TC) control valve is increased and a proportion of the pressure acting on the boost pressure control (BPC) valve pressure servo is allowed through to the turbocharger (TC) inlet. Control pressure is reduced, the boost pressure control (BPC) valve opens later and turbocharger (TC) pressure can increase.