Alternator DDE4.0
The alternator has two interfaces to the DDE:
- S_DF, acknowledgment alternator load
The alternator forwards its current force by means of a square-wave signal to the DDE control module. The load can lie between 5% and 95%.
- S_ALTV, activation of alternator
For torque reduction in certain states, the DDE activates the alternator. The activation can reduce the normal charge voltage from around 14.9 V to around 12.5 V. This reduces the torque required to drive the alternator.
The following table shows the dependency of activation value and charge voltage:
Activation value
|
Charge voltage
|
High
|
around 14.9 V
|
Low
|
around 12.5 V
|
At engine startup, the charge voltage is reduced for 3 seconds.
The following states lead to a reduction in the charge voltage for 5 seconds:
- Starting state AND coolant temperature < 100°C
- Strong acceleration AND coolant temperature < 100°C