Control valve, VIM damper (454), Simtec: Connection

CONNECTOR PINOUTS REFERENCE

Pin No.	Signal type	Description
1	Power supply B+	Valve's power supply from main relay 229
2	Control	Valve's control from ECM pin 2 (A)

Fig 1: Circuit Diagram Control Valve, VIM Damper

Courtesy of SAAB-SCANIA OF AMERICA, INC.

To achieve a high degree of fullness (volumetric efficiency - VE) over a broad engine speed register, the length of the channels is variable - long or short.

Long channels generate good VE and thereby high torque at low rpm. At high rpm, the long intake channels provide too much restriction. The intake channels are made short in order to achieve a high VE at high engine speed.

This contributes to the engine's flat torque character - 90% or more of maximum torque over the interval 2400-5700 rpm.

A non-energised solenoid valve generates an unactuated vacuum unit and thereby short intake channels.