Alternator Interface, Function - GF07.10-D-1009HD

ENGINES 651.955/956/957 in MODEL 906 

with CODE (XZ1) Model generation 1 

with CODE (MZ0) Blue EFFICIENCY 

Function requirements 

• Circuit 87M On
• Circuit 61 ON

General 

Using the alternator interface, messages are exchanged via the Local Interconnect Network (LIN) between the alternator with LIN bus (G2/7) (for model 906) and the CDI control unit (N3/28) and the control response of the alternator with LIN bus is controlled. For this purpose, the CDI control unit reads in the following sensor and signal:

• Crankshaft sensor (L5/10), engine speed
• Battery voltage (G1) over "circuit 30"

Function sequence 

The CDI control unit controls the alternator with LIN bus control response in order, for example, to reduce the regulation voltage (charging voltage) when the engine is at idle and the battery is sufficiently charged.

This reduces the engine load, thus also reducing fuel consumption and improving exhaust gas emissions.

The CDI control unit controls the following functions:

• Switching on of the alternator with LIN bus after the engine start.

  Regulation of the alternator with LIN bus based on characteristic maps stored in the CDI control unit. To do this, the control voltage is preset by the CDI control unit.

• For a higher change in load of the alternator with LIN bus (for model 906) the regulation voltage is adapted with some delay in idle to the idle speed to stabilize.
• Protect the alternator with LIN bus (for model 906) against overheating.
• Generate the circuit 61 signal (the alternator with LIN bus in function) (for model 906).
• Report detected faults to the instrument cluster (A1) for actuation of the respective warning lamps and display messages.

The alternator with LIN bus (for model 906) performs continuous self-diagnosis and sends the results to the CDI control unit on request. The control unit compares the results with other signals (for example, engine RPM, battery voltage, time since engine start) and thus detects any fault on the alternator with LIN bus (for model 906).

For alternators with an alternator interface, line "circuit 61" is not needed. Using information received by the CDI control unit over the alternator interface, the "circuit 61 signal" is simulated in the CDI control unit and sent through an output stage connected to ground (e.g. for the instrument cluster).