Method for controlling output power of an energy storage device in a powertrain system
View Patent ↗A method for controlling a powertrain system includes monitoring a state-of-charge of the energy storage device and determining a first set of electric power limits and a second set of electric power limits based on the state-of-charge of the energy storage device. The method further includes providing a power range for opportunity charging and discharging of the energy storage device based on the first set of electric power limits. The method further includes providing a power range for controlling output power of the energy storage device based on the second set of electric power limits.
1. Method for controlling a powertrain system comprising an engine, a torque machine, a transmission device and an energy storage device, the transmission device operative to transfer power between the engine, the torque machine and an output member to generate an output torque, the method comprising:
monitoring an operator torque request;
monitoring a state-of-charge of the energy storage device;
determining a first set of maximum and minimum electric power limits and a second set of maximum and minimum electric power limits based on the state-of-charge of the energy storage device;
providing a first power range corresponding to the first set of maximum and minimum electric power limits;
providing a second power range corresponding to the second set of maximum and minimum electric power limits;
identifying a no discharge range and a no charge range between said limits of the second power range;
identifying an opportunity charge and discharge range between said limits of the first power range;
identifying a forced discharge range between said maximum limits of the first and the second power ranges;
identifying a free charge range between said minimum limits of the first and the second power ranges;
selecting one of the no discharge range, the forced discharge range, the opportunity charge and discharge range, the free charge range, and the no charge range responsive to the state-of-charge of the energy storage device; and
selecting a preferred input torque from the engine responsive to the operator torque request and limited by the selected one of the no discharge range, the forced discharge range, the opportunity charge and discharge range, the free charge range, and the no charge range.
2. The method of claim 1 , further comprising permitting free charging of the energy storage device and restricting opportunity charging of the energy storage device when the state-of-charge is in the free charge range.
3. The method of claim 1 , further comprising permitting forced discharging of the energy storage device and restricting opportunity discharging of the energy storage device when the state-of-charge is in the forced discharge range.
4. The method of claim 1 , further comprising restricting free charging of the energy storage device and opportunity charging of the energy storage device when the state-of-charge is in the no charge range.
5. The method of claim 1 , further comprising restricting forced discharging of the energy storage device and opportunity discharging of the energy storage device when the state-of-charge is in the no discharge range.
6. The method of claim 1 , further comprising permitting opportunity charging and opportunity discharging of the energy storage device when the state-of-charge of the energy storage device is in the opportunity charge and discharge range.
7. The method of claim 1 , further comprising operating the engine in a cylinder deactivation state when opportunity discharging the energy storage device.
8. The method of claim 1 , wherein selecting a preferred input torque from the engine responsive to the operator torque request and limited by the selected one of the no discharge range, the forced discharge range, the opportunity charge and discharge range, the free charge range, and the no charge range comprises:
providing a search range of engine operating points corresponding to the selected one of the no discharge range, the forced discharge range, the opportunity charge and discharge range, the free charge range, and the no charge range;
determining costs associated with a plurality of engine operating points within the search range of engine operating points; and
selecting the preferred engine operating point comprising an engine operating point having a minimum cost within the search range of engine operating points.
9. The method of claim 8 wherein determining costs associated with the plurality of engine operating points within the search range of engine operating points comprises determining costs based upon power loss costs within the powertrain.
10. The method of claim 9 , wherein the power loss costs comprise fuel consumption costs.
11. The method of claim 1 , wherein the first set of maximum and minimum electric power limits are more constrained than the second set of maximum and minimum electric power limits.
12. Method for controlling a powertrain system comprising an engine, a torque machine, a transmission device and an energy storage device, the transmission device operative to transfer power between the engine, the torque machine and an output member to generate an output torque, the method comprising:
monitoring a state-of-charge of the energy storage device;
determining maximum and minimum predicted electric power limits and maximum and minimum long-term electric power limits corresponding to the state-of-charge of the energy storage device;
identifying a free charge range between the minimum predicted electric power limit and the minimum long-term electric power limit; and
permitting free charging of the energy storage device and restricting opportunity charging of the energy storage device based on the predicted electric power limits and the long-term electric power limits when the state-of-charge is in the free charge range.
13. The method of claim 12 , further comprising determining a preferred engine operating point based upon discharging the energy storage device when the state-of-charge is in the free charge range.
14. The method of claim 13 , further comprising controlling output power of the energy storage device to charge the energy storage device when the preferred operating point based upon discharging the energy storage device is determined and when the state-of-charge is in the free charge range.
15. Method for managing electric power in a powertrain system comprising an energy storage device, an engine, a second torque generating device and a transmission device operative to transfer power among an output member, the engine and the second torque generating device, the second torque generating device electrically coupled to an energy storage device, the method comprising:
monitoring a state-of-charge of the energy storage device;
determining maximum and minimum predicted electric power limits and maximum and minimum long-term electric power limits corresponding to the state-of-charge of the energy storage device;
identifying a forced discharge range between the minimum predicted electric power limit and the minimum long-term electric power limit; and
permitting forced discharging of the energy storage device and restricting opportunity discharging of the energy storage device utilizing the predicted electric power limits and the long-term electric power limits when the state-of-charge is in the forced discharge range.
16. The method of claim 15 , further comprising:
determining a preferred engine operating point based upon charging the energy storage device when the state-of-charge is in the forced discharge range; and
controlling output power of the energy storage device to discharge the energy storage device when the preferred operating point based upon charging the energy storage device is determined and when the state-of-charge is in the forced discharge range.