Functional description

The alternator maintains the desired level of vehicle voltage. The alternator also supplies all electrical consumer units during driving. The controller regulates the output voltage of the electrically excited alternator with uncontrolled rectifier by applying the excitation current.

Fig 1: Identifying Alternator And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.

Example

For the alternator with serial data interface, the following functions are implemented in the engine control unit:

• Switching the alternator on and off on the basis of defined parameters
• Temperature-dependent maximum permitted power consumption of the alternator
• Calculation of the alternator input torque and the alternator current based on the parameters transmitted by the alternator regulator.
• Control of the reaction of the alternator with addition of high power consumers (load-response function)
• Alternator diagnosis and diagnosis of the data line between alternator and engine control unit.
• Storage of any faults that occur on the alternator in the fault memory of the engine control unit