Methods and system for transitioning between control modes while creeping
Systems and methods for transitioning a torque source between speed control and torque control modes during a vehicle creep mode are disclosed. In one example, torque of an electric machine is adjusted in response to a torque converter model. The torque converter model provides for a locked or unlocked torque converter clutch.
1. A driveline method, comprising:
operating a torque source in a speed control mode during a vehicle creep mode while a clutch of a torque converter is open;
transitioning operating the torque source from the speed control mode to a torque control mode and locking the clutch during the vehicle creep mode in response to a vehicle operating condition; and
adjusting torque of the torque source in response to torque converter impeller speed when the torque converter clutch is unlocked.
2. The method of claim 1 , further comprising adjusting torque of the torque source in response to a virtual torque converter impeller speed when the torque converter clutch is locked.
3. The method of claim 2 , where the virtual torque converter impeller speed is based on operating conditions of a driveline integrated starter/generator.
4. The method of claim 2 , where the virtual torque converter impeller speed is based on operating conditions of an engine.
5. The method of claim 1 , further comprising adjusting torque of the torque source in the torque control mode in response to a filtered torque.
6. The method of claim 5 , where the filtered torque is based on a torque when the torque source is operated in the speed control mode.
7. A driveline method, comprising:
operating a torque source in a speed control mode during a vehicle creep mode while a clutch of a torque converter is open;
transitioning operating the torque source from the speed control mode to a torque control mode and locking the clutch during the vehicle creep mode in response to a vehicle operating condition; and
adjusting torque of the torque source in response to a virtual torque converter impeller speed when the torque converter clutch is locked.
8. The method of claim 7 , where the virtual torque converter impeller speed is based on operating conditions of a driveline integrated starter/generator.
9. The method of claim 7 , where the virtual torque converter impeller speed is based on operating conditions of an engine.
10. A driveline method, comprising:
operating a torque source in a speed control mode during a vehicle creep mode while a clutch of a torque converter is open;
transitioning operating the torque source from the speed control mode to a torque control mode and locking the clutch during the vehicle creep mode in response to a vehicle operating condition; and
adjusting torque of the torque source in the torque control mode in response to a filtered torque, where the filtered torque is based on a torque when the torque source is operated in the speed control mode.