Fig. 2.209. Boost pressure control electromagnetic valve: 1 – pneumatic drive; 2 – electromagnetic valve
The pneumatic drive of the boost pressure regulator is controlled by an electromagnetic valve according to commands from the injection system ECU (fig. 2.209).
The pneumatic drive of the boost pressure regulator is controlled by an electromagnetic valve according to commands from the injection system ECU.
In the initial position, the boost pressure regulator valve is closed and the solenoid valve is open.
In the open position, the electromagnetic valve connects the turbocharger outlet (boost pressure) with pneumatic drive, so the boost pressure acts directly on the pneumatic drive and the pressure regulator valve opens.
When controlling the electromagnetic valve, the boost pressure signal (measured at the turbocharger outlet) is fed to the turbocharger input. Consequently, the boost pressure is removed from the pneumatic drive and the pressure regulator valve closes.
After the engine starts, the supply voltage is supplied to the electromagnetic valve, which is initially open. However, for a certain period of time, the duration of which depends on the coolant temperature, the boost pressure is limited and the engine crankshaft speed cannot exceed 2500 min⁻¹.
This is necessary so that the oil has time to reach the turbocharger bearings.
Fig. 2.210. Boost pressure control diagram
[Material taken from an online portal: renaultbook.ru]