Component description for boost pressure control pressure transducer

P09.40-2320-01

View of engine from rear left

N92/2 ECI ignition module, left cylinder bank

Y31/5 Boost pressure control pressure transducer

Location

The pressure transducer is located behind the LH cylinder head.

Task

For the boost pressure control, the pressure transducer actuates the vacuum cells with boost pressure from the charge air cooler of the RH cylinder bank.

Design

The pressure transducer consists of a solenoid, a
2-sided valve plate, three air connections and a 2-pin plug connection. The coil resistance is about 23 Ω at 20°C.

P09.20-2146-75

Function

1 Boost pressure modulated to the vacuum cells (corresponding to a duty cycle of 5 to 95 %)

2 Atmospheric pressure (atmospheres)

3 Boost pressure from charge air cooler of RH cylinder bank

4 2-pin plug connection.

A Pressure transducer energized (actuated)

B Pressure transducer deenergized

For the boost pressure control, the ME-SFI [ME] control unit (N3/10) actuates the pressure transducer by a PWM signal, with a duty cycle of 5 to 95 %.

The voltage supply takes place from "circuit 87 M1".

In the energized state, connection 3 is closed off by the valve plate, and the coil armature actuates the valve plate, which increases the length of opening time to atmospheric pressure as the duty cycle lengthens. This causes the boost pressure on the vacuum cells to fall to nothing. Through a linkage, these cells actuate the boost pressure control flaps and the bypasses are partially and then fully closed (boost pressure rises).

In the deenergized state, connection 2 is closed by the valve plate and all the boost pressure builds up in the vacuum cell. Through a linkage, the vacuum cells then open the boost pressure control flaps, which close off the bypasses, and the boost pressure falls.