Bit-Serial Data Interface (BSD)

BSD Interface To The Alternator

The alternator with BSD interface can actively communicate with the engine control module. The alternator is not linked to the charge indicator lamp, only to the engine control module. The alternator can detect a variety of faults.

Function
The following functions have been implemented in the engine control module for the alternator with BSD interface:
- Activating/deactivating the alternator on the basis of applicable parameters
- Specification of the maximum permitted degree of utilization of the alternator
- Control of the alternator's load response
- Calculation of the alternator moment degree of utilization
- Diagnosis of the data line between the alternator and the engine control
- Filing of alternator faults in the fault memory

Activating the load control lamp in instrument cluster via CAN

In comparison to alternators used so far, the display strategy of the load control lamp does not change when the alternator with BSD interface.

The basic function of the alternator is also ensured if the communication between the alternator and the engine control is interrupted.

Possible faults
The following possible faults can be distinguished from fault entries:

High temperature control: The alternator is overloaded; to be safe, the alternator voltage is reduced until the alternator has cooled down again. The charge indicator lamp does not light up.
- Mechanical fault: The alternator is mechanically blocked or the belt drive has failed.
- Electrical fault: Exciter diode defect, excite interruption, overvoltage due to controller defect.
- Communication failure: Line defect between the engine control and alternator.

The following cannot be detected: Coil interruption or short-circuit

Battery charge indicator lamp
The signal for the charge indicator lamp to light up is transferred across CAN to the instrument cluster. The charge indicator lamp lights up if there is mechanical and electrical fault (see above).

Detection
The above-mentioned calculation of the alternator moment and the rate of utilization of the alternator are heavily dependent on the type (performance) and manufacturer.

This is why the alternator provides the engine control with this data. The engine control adapts its calculation and set values to the exact type.

Aim
The precise calculation of the alternator moment and control of the load response function enables good idling of the engine.

Control of the alternator voltage based on nominal values from the engine control enables a good charge balance of the battery.