Alternator Control, Basic Function - GF15.40-P-1058A
Engine all (4xWD)
Engine all (CAR)
Overview
This document contains information on:
- General
- Function requirements
- Function
- Alternator control function
- Alternator self-diagnosis
General
To optimally control the charging voltage of the alternator, the alternator and the combustion Engine control unit exchange data via the alternator control function. The alternator control function makes the exchanged data plausible and corrects it depending on the vehicle's operating state. In addition, the alternator control function records mechanical or electrical faults in the alternator.
Function requirements
- Engine management ON (circuit 87M)
- Engine in operation
Function
Alternator control function
The alternator control function requests the optimized charging voltage from the alternator. The optimized charging voltage is calculated from the following information:
- Specified voltage of the alternator management
- Corrections of output management. In order to calculate the optimized charging voltage for the alternator, the following processes take place:
- Reading out the operating rate of the alternator:
In order to control the power output of the alternator, the combustion Engine control unit assesses the operating rate of the alternator. To this end, it uses the data transmitted by the alternator.
- Calculating the specified voltage of the alternator:
In order to determine the specified voltage of the alternator, the powertrain control unit uses the operating rate of the alternator.
This involves the alternator control function.
- Optimizing the specified voltage of the alternator. In order to record the on-board electrical system voltage, the following information is read in and compared:
- The calculated specified voltage of the alternator
- The actual value of the alternator voltage
- Reading out the operating rate of the alternator:
In order to compensate for fluctuations in the on-board electrical system voltage in certain vehicle operating states, the output management optimizes the specified voltage, e.g. at Engine start. This results in the optimized charging voltage.
Alternator self-diagnosis
The alternator performs self-diagnosis continuously. On request, it provides its status as a signal.
The alternator control function detects the following electrical or mechanical faults:
- Line of the alternator control function has an open circuit
- Control or diodes defective
- Interruption or short circuit in the stator
- Excitation interruption
- Charging voltage too low or too high
- Cracked poly-V-belt
- Poly-V belt tension too low or too high
| Function schematics | |||
| Function schematic for alternator interface | Engine 260, 282, 608 in model 118, 177, 247 Engine 264 in model 167 | PE07.10-P-2504-97A | |
| Engine 176, 177 in model 167 | PE07.10-P-2504-97B | ||
| Engine 139 in model 118, 177, 247 | PE07.10-P-2504-97C | ||
| Engine 256 in model 213, 238 as of model year 2021 Engine 264 in model 213, 238, 257 as of model year 2021 Engine 654 in model 118, 167, 177, 247 Engine 654 in model 213, 238, 257 as of model year 2021 Engine 656 in model 167 | PE07.10-P-2504-97D | ||
| Engine 177.8 in model 232 except code ME10 (Hybrid vehicle (plug-in, PHEV)) | PE07.10-P-2504-97E | ||
| Engine 254 in model 206 | PE07.10-P-2504-97F | ||
| Engine 279 in model 223 | PE07.10-P-2504-97G | ||
| Engine 656 in model 223 | PE07.10-P-2504-97H | ||
| Engine 656 in model 464 | PE07.10-P-2504-97I | ||
| Additional basic functions | |||
| Combustion Engine control unit, basic function | GF07.08-P-9890A |