SELF-LEARNING CONTROL SYSTEM FOR PLUG-IN HYBRID VEHICLES

• US 20090114463A1
• Filed: 06/12/2008
• Published: 05/07/2009
• Est. Priority Date: 06/12/2007
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: DeVault, Robert C.
• Granted Patent: US 7,849,944 B2
• Time in Patent Office: Days
• US Class Current: 180/65.290
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/12 using control strategies taking into account route information estimation or calculation of non-directly measurable driving parameters B60W40/00
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2530/10 Weight
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

A system is provided to instruct a plug-in hybrid electric vehicle how optimally to use electric propulsion from a rechargeable energy storage device to reach an electric recharging station, while maintaining as high a state of charge (SOC) as desired along the route prior to arriving at the recharging station at a minimum SOC. The system can include the step of calculating a straight-line distance and/or actual distance between an orientation point and the determined instant present location to determine when to initiate optimally a charge depleting phase. The system can limit extended driving on a deeply discharged rechargeable energy storage device and reduce the number of deep discharge cycles for the rechargeable energy storage device, thereby improving the effective lifetime of the rechargeable energy storage device. This “Just-in-Time strategy can be initiated automatically without operator input to accommodate the unsophisticated operator and without needing a navigation system/GPS input.

Claims

1. A system for optimizing rechargeable energy storage device depletion comprising:

a plug-in hybrid electric vehicle having an electric motor, a consumable fuel powered means, and a rechargeable energy storage device to power the electric motor, wherein the rechargeable energy storage device is configured to be recharged from a recharging station or the consumable fuel powered means, the rechargeable energy storage device having a minimum state of charge (SOC); and

a controller comprising a computer configured to receive data inputs and provide outputs, the controller configured to define an orientation point representative of a geographic location of the recharging station, to determine a current location of the vehicle, to calculate a straight-line distance between the current location of the vehicle and the orientation point, and to monitor a state of charge (SOC) of the rechargeable energy storage device;

the controller is further configured to determine an optimal rechargeable energy storage device depletion strategy based on the straight-line distance to substantially sustain the monitored state of charge (SOC) when the straight-line distance is increasing, and to selectively deplete the rechargeable energy storage device to reach about the minimum state of charge (SOC) as the straight-line distance approaches about zero; and

the controller is further configured to generate the outputs to implement the optimal rechargeable energy storage device depletion strategy.

2. The system of claim 1, wherein the rechargeable energy storage device is a battery.

3. The system of claim 2, wherein the battery is one of a lithium-ion battery and a nickel-metal hydride battery.

4. The system of claim 1 further comprising a voltage detection sensor to detect voltage of the recharging station.

5. The system of claim 1 further comprising a detachable navigation system being configured to be selectively removably attached to the controllers the detachable navigation system including a global positioning system and a map database, wherein the detachable navigation system is configured to provide a latitude, a longitude, and an elevation for the orientation point and for the current location of the vehicle as data inputs for the controller to calculate an actual distance between the orientation point and the current location.

6. The system of claim 5, wherein the controller is further configured to determine the optimal rechargeable energy storage device depletion strategy based on the straight-line distance when the detachable navigation system is detached, and based on the actual distance when the detachable navigation system is attached.

7. The system of claim 1, wherein the consumable fuel powered means is one of an internal combustion engine (ICE) and a hydrogen fuel cell.

8. The system of claim 1, wherein the rechargeable energy storage device is further configured to be recharged from a regenerative means.

9. The system of claim 1 further comprising a detachable global positioning system receiver configured to be selectively removably attached to the controller, wherein the detachable global positioning system receiver provides a latitude and a longitude for the orientation point and for the current location of the vehicle as data inputs for the controller to calculate an actual distance.

10. The system of claim 9, wherein the controller is configured to determine the optimal rechargeable energy storage device depletion strategy based on the straight-line distance when the global positioning system receiver is detached and based on either the straight-line distance or the actual distance when the global positioning system receiver is attached.

11. A method of optimizing depletion of a rechargeable energy storage device of a plug-in hybrid electric vehicle to a minimum state of charge (SOC), the method comprising the steps of:

defining an orientation point representative of a geographic location of a recharging station;

repeatedly determining a present location of said vehicle in response to changes in location of said vehicle;

repeatedly calculating a straight-line distance between the orientation point and the determined present location of said vehicle;

monitoring a state of charge (SOC) of said rechargeable energy storage device;

substantially sustaining the monitored state of charge (SOC) of said rechargeable energy storage device when the calculated straight-line distance between the orientation point and the determined present location is increasing;

initiating depletion of said rechargeable energy storage device to about said minimum state of charge (SOC) when the calculated straight-line distance between the orientation point and the determined present location is decreasing; and

said rechargeable energy storage device about reaching said minimum state of charge (SOC) when the calculated straight-line distance is about zero.

12. The method of claim 11, wherein the orientation point is defined by sensing an input signal indicative of the recharging station;

and storing the orientation point representative of the geographic location of the recharging station.

13. The method of claim 11 further comprising the step of reverting to one of substantially sustaining the monitored state of charge (SOC) of said rechargeable energy storage device and initiating depletion of said rechargeable energy storage device to said about minimum state of charge (SOC), whichever is the most recently executed, when the calculated straight-line distance is substantially unchanged.

14. The method of claim 11 further comprising the step of calculating an estimated state of charge (SOC) needed for the vehicle to return to the orientation point with said rechargeable energy storage device being at about said minimum state of charge (SOC).

15. The method of claim 14 further comprising the step of comparing the calculated estimated state of charge (SOC) with the monitored state of charge (SOC) needed for the vehicle to return to the orientation point with said rechargeable energy storage device being at about said minimum state of charge (SOC).

16. The method of claim 15 further comprising the steps of:

substantially sustaining the monitored state of charge (SOC) of said rechargeable energy storage device when the monitored state of charge (SOC) is less than the calculated estimated state of charge (SOC); and

initiating depletion of said rechargeable energy storage device to about the calculated estimated state of charge (SOC) when the monitored state of charge (SOC) is greater than the calculated estimated state of charge (SOC).

17. The method of claim 15 further comprising the step of initiating recharge of said rechargeable energy storage device to about the calculated estimated state of charge (SOC) when the monitored state of charge (SOC) is less than the calculated estimated state of charge (SOC).

18. The method of claim 11 further comprising the step of comparing the calculated straight-line distance with a predetermined limited distance requirement of said rechargeable energy storage device.

19. The method of claim 18 further comprising the step of depleting said rechargeable energy storage device to about said minimum state of charge (SOC) when the calculated straight-line distance is less than the predetermined limited distance requirement of said rechargeable energy storage device.

20. The method of claim 11 further comprising the step of calculating an actual distance between the orientation point and the determined present location of said vehicle.

21. The method of claim 20 further comprising the steps of:

substantially sustaining the monitored state of charge (SOC) of said rechargeable energy storage device when the calculated actual distance is increasing from the orientation point;

initiating depletion of said rechargeable energy storage device to said minimum state of charge (SOC) when the calculated actual distance is decreasing from the orientation point;

said rechargeable energy storage device about reaching said minimum state of charge (SOC) when the calculated actual distance is about zero.

22. The method of claim 21 further comprising the steps of comparing the calculated actual distance with a predetermined limited distance requirement of said rechargeable energy storage device;

and depleting said rechargeable energy storage device to about said minimum state of charge (SOC) when the calculated actual distance is less than the predetermined limited distance requirement of said rechargeable energy storage device.

23. The method of claim 20 further comprising the step of detecting one of a navigation system and a global positioning system receiver, wherein the one of the navigation system and the global positioning system receiver provides inputs for calculating either the straight-line distance or the actual distance between the orientation point and the determined present location of said vehicle.

24. The method of claim 11, wherein the steps are performed fully automated without external inputs from outside said vehicle.

25. The method of claim 11 further comprising the steps of initiating depletion of said rechargeable energy storage device to about an optimal state of charge (SOC) and substantially sustaining the state of charge (SOC) of said rechargeable energy storage device at about the optimal state of charge (SOC) before depleting said rechargeable energy storage device to about the minimum state of charge (SOC), wherein the optimal state of charge (SOC) is greater than the minimum state of charge (SOC).

26. The method of claim 25, further comprising the steps of determining a target state of charge (SOC) for future depletion before depleting said rechargeable energy storage device to about the minimum state of charge (SOC);

and initiating recharge of said rechargeable energy storage device to about the determined target state of charge (SOC).

27. The method of claim 26, wherein the determined target state of charge (SOC) for future depletion is greater than the optimal state of charge (SOC).

28. The method of claim 11, wherein the orientation point is defined by sensing an input signal indicative of the recharging station, which is a first recharging station, and defining the orientation point representative of the geographic location of the first recharging station, the method further comprising the steps of sensing an input signal indicative of a second recharging station at a different geographic location than the first recharging station;

and storing a destination point representative of the geographic location of the second recharging station.

29. The method of claim 28, where the straight-line distance is a first straight-line distance, the method further comprising the steps of:

repeatedly calculating a second straight-line distance between the destination point and the determined present location of said vehicle;

comparing each of the first straight-line distance and the second straight-line distance with a predetermined limited distance requirement of said rechargeable energy storage device;

comparing the first straight-line distance and the second straight-line distance to determine which is smaller;

initiating depletion of said rechargeable energy storage device to about said minimum state of charge (SOC) when either the first straight-line distance or the second straight-line distance is less than the predetermined limited distance requirement of said rechargeable energy storage device.

30. The method of claim 29 further comprising the step of substantially sustaining the monitored state of charge (SOC) of said rechargeable energy storage device when both the first straight-line distance and the second straight-line distance are greater than the predetermined limited distance requirement of said rechargeable energy storage device.

31. A computer-usable medium comprising a plurality of computer readable instructions stored thereon that, in response to execution by a processor, causes the processor to:

generate and store an orientation point for a plug-in hybrid electric vehicle having a rechargeable energy storage device, wherein the orientation point comprises a recharging station;

determine, at a first time instant, a first straight-line distance between a first current location of the vehicle and the orientation point,

determine, at a second time instant, a second straight-line distance between a second current location of the vehicle and the orientation point,

initiate a charge sustaining phase of the rechargeable energy storage device when the second straight-line distance is greater than the first straight-line distance; and

initiate a charge depleting phase of the rechargeable energy storage device when the second straight-line distance is less than the first straight-line distance, and the second straight-line distance is less than a limited distance requirement of the rechargeable energy storage device.

32. The computer-usable medium of claim 31, wherein the plurality of computer readable instructions further causes the processor to initiate one of substantially sustaining the monitored state of charge (SOC) of said rechargeable energy storage device and depleting said rechargeable energy storage device to about said minimum state of charge (SOC), whichever is the most recently initiated, when the second straight-line distance is substantially unchanged from the first straight-line distance.

33. The computer-usable medium of claim 31, wherein the plurality of computer readable instructions further causes the processor to determine, at the first time instant, a first actual distance between the first current location of the vehicle and the orientation point;

and determine, at the second time instant, a second actual distance between the second current location of the vehicle and the orientation point.

34. The computer-usable medium of claim 33, wherein the plurality of computer readable instructions further causes the processor to initiate the charge sustaining phase when the second actual distance is more than the limited distance requirement of the rechargeable energy storage device;

and initiate the charge depleting phase when the second actual distance is less than the limited distance requirement of the rechargeable energy storage device.

35. The computer-usable medium of claim 31, wherein the plurality of computer readable instructions further causes the processor to detect the recharging station when the recharging station is connected to the vehicle.

36. The computer-usable medium of claim 35, wherein the plurality of computer readable instructions further causes the processor to determine a recharge time from the recharging station during a period of lowest grid electric demand and to initiate recharge at the determined recharge time with electricity from the detected recharging station.

37. The computer-usable medium of claim 35, wherein the plurality of computer readable instructions further causes the processor to determine a comfort level of a cabin of the plug-in hybrid electric vehicle and to initiate a preconditioning phase to condition the cabin to the comfort level with electricity from the detected recharging station or from the rechargeable energy storage device.

38. The computer-usable medium of claim 37, wherein the plurality of computer readable instructions further causes the processor to initiate a heating/defrost system to pre-heat the cabin to the comfort level or an air conditioning system to pre-cool the cabin to the comfort level, during the preconditioning phase.