Methods and systems for a four wheel drive vehicle driveline
Systems and methods for improving operation of a hybrid vehicle are presented. In one example, driveline operation may be adjusted in response to operating the hybrid vehicle in a four wheel drivel low gear range. The approaches may improve vehicle drivability and reduce driveline degradation.
1. A method of adjusting operation of a hybrid vehicle, comprising:
automatically restarting an engine in response to release of a vehicle brake while the hybrid vehicle is operating in a four wheel drive low gear range; and
stopping engine rotation in response to a vehicle battery reaching a first threshold state of charge based on operating the hybrid vehicle in the four wheel drive low gear range.
2. The method of claim 1 , further comprising stopping engine rotation in response to the vehicle battery reaching a second threshold state of charge based on operating the hybrid vehicle in a mode other than the four wheel drive low gear range.
3. The method of claim 2 , where the mode other than the four wheel drive low gear range is a two wheel drive mode.
4. The method of claim 2 , where the mode other than the four wheel drive low gear range is a four wheel drive high gear range.
5. The method of claim 1 , further comprising opening and closing a driveline disconnect clutch according to a first schedule based on operating the hybrid vehicle in the four wheel drive low gear range.
6. The method of claim 5 , further comprising opening and closing the driveline disconnect clutch according to a second schedule based on operating the hybrid vehicle in a two wheel drive mode, the second schedule different from the first schedule.