CDI external quantity control, function - GF07.16-P-3011GZ

ENGINE 642 in MODEL 164.1 /8, 251.0 /1 

The CDI control unit (N3/9) intervenes with an external quantity control if an increase or decrease on the engine speed and engine load is requested from another system. Here the CDI control unit communicates via the Controller Area Network bus Class C (engine compartment) (CAN-C) with the following control units:

• Control unit for intelligent servo module for DIRECT SELECT (A80) for the selector lever position
• ESP control unit (N47-5) for the message "Drive torque regulation active"
• Fully integrated transmission control (VGS) control unit (Y3/8n4) for the message "FW_HIGH", driving resistance high
• EIS [EZS] control unit (N73), for the message "CRASH_1", rollover event 1
• EIS [EZS] control unit, for the message "COMP_ON", refrigerant compressor (A9) actuated

The CDI control unit increases or reduces the injection quantity. In order to adapt the injection quantity the fuel pressure in the rail is increased or decreased by the pressure regulator valve (Y74) and the quantity control valve (Y94) via the CDI control unit. The actuation time of the fuel injectors (Y76) is lengthened or shortened appropriately at the same time.

If the CDI control unit receives the message "CRASH_1", it interrupts the fuel supply in order to stop fuel escaping and to stop the engine.