Regenerative braking system for a batteriless fuel cell vehicle

• US 6,488,345 B1
• Filed: 08/16/2001
• Issued: 12/03/2002
• Est. Priority Date: 08/16/2001
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Woody, George R., Willimowski, Peter, Fasse, Martin
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US09/931,508
• Time in Patent Office: 474 Days
• Field of Search: 303/152, 303/2-3, 303/20, 701/22, 180/165, 180/65-- 6, 180/197, 429/17, 429/9, 429/12, 429/13, 429/19, 429/34, 429/218.2, 429/24-26, 318/139, 318/376, 320/101, 320/104, 320/147, 604/13, 604/14, 188/156, 188/158
• US Class Current: 303/152
• CPC Class Codes: B60K 1/04 of the electric storage means for propulsion exchanging batteries for electric propulsion of vehicles B60L53/80; for auxiliary purposes only B60R16/04; supplying batteries to, or removing batteries from, vehicles B60S5/06
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: B60L 58/33 by cooling
• CPC Class Codes: B60L 58/34 by heating
• CPC Class Codes: B60L 7/10 Dynamic electric regenerative braking B60L7/22 takes precedence
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 8/00 Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force by changing number of effective brake cylinders in power brake systems B60T17/10
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A regenerative braking system and method for a batteriless fuel cell vehicle includes a fuel cell stack, a plurality of ancillary loads, and a regenerative braking device that is coupled to at least one wheel of the vehicle. The regenerative braking device powers ancillary loads when the vehicle is coasting or braking. The fuel cell powers the loads when the vehicle is accelerating or at constant velocity. The regenerative braking device dissipates power in an air supply compressor when the vehicle is traveling downhill to provide brake assistance. The compressor can be run at high airflow and high pressure to create an artificially high load. A bypass valve is modulated to adjust the artificially high load of the compressor. A back pressure valve protects the fuel cell stack from the high airflow and pressure. A controller controls a brake torque of the regenerative braking device as a function of vehicle speed and modulates the bypass valve.

Claims

1. A regenerative braking system for a batteriless fuel cell vehicle, comprising:

a fuel cell stack;

an ancillary load; and

a regenerative braking device coupled to at least one wheel of said vehicle, wherein said regenerative braking device powers said ancillary load when said vehicle is coasting or braking and wherein said fuel cell powers said ancillary load when said vehicle is accelerating or traveling at a constant velocity.

2. The regenerative braking system of claim 1 wherein said ancillary load is selected from the group of fans, pumps, airconditioning compressor, cabin heater, 12 volt battery, and an air compressor for said fuel cell stack.

3. The regenerative braking system of claim 1 further comprising an air compressor for said fuel cell stack.

4. The regenerative braking system of claim 3 further comprising a bypass valve.

5. The regenerative braking system of claim 4 wherein when said vehicle is traveling downhill, said air compressor is run at high airflow and high pressure to create an artificially high ancillary load and said bypass valve is modulated to vary said artificially high ancillary load of said air compressor to provide brake assistance.

6. The regenerative braking system of claim 5 further comprising a back pressure valve that protects said fuel cell stack from said high airflow and said high pressure.

7. The regenerative braking system of claim 5 further comprising a controller.

8. The regenerative braking system of claim 7 wherein said controller controls a brake torque of said regenerative braking device as a function of vehicle speed.

9. The regenerative braking system of claim 7 wherein said controller modulates said bypass valve.

10. The regenerative braking system of claim 1 wherein said regenerative braking device is an electric traction system.

11. The regenerative braking system of claim 1 wherein when said vehicle is coasting or braking, delivery of air and fuel to said fuel cell stack is interrupted.

12. The regenerative braking system of claim 11 further comprising a controller.

13. The regenerative braking system of claim 12 wherein said controller sets a brake torque of said regenerative braking device as a function of vehicle speed.

14. The regenerative braking system of claim 12 wherein said controller modulates said bypass valve.

15. The regenerative braking system of claim 1 wherein said regenerative braking device is an electric traction system.

16. A regenerative braking system for a batteriless fuel cell vehicle, comprising:

a fuel cell stack;

an air compressor that provides air to said fuel cell stack;

a regenerative braking device coupled to at least one wheel of said vehicle and to said air compressor; and

a bypass valve, wherein said air compressor is run at high pressure and high airflow to create an artificial load on said regenerative braking device, and wherein said artificial load is modulated by said bypass valve.

17. The regenerative braking system of claim 16 further comprising a back pressure valve for protecting said fuel cell stack when said air compressor is dissipating said power.

18. A method for operating a batteriless fuel cell vehicle, comprising the steps of:

providing a fuel cell stack;

providing air to said fuel cell stack using an air compressor;

coupling a regenerative braking device to at least one wheel of said vehicle;

connecting a regenerative braking device to said air compressor; and

dissipating power that is produced by said regenerative braking device when said vehicle is traveling downhill using said air compressor.

19. The method of claim 18 further comprising the step of modulating a bypass valve to adjust said power that is dissipated by said air compressor.

20. The method of claim 19 further comprising the step of running said air compressor at high airflow and high pressure to create an artificial loss when said vehicle is traveling downhill.

21. The method of claim 20 further comprising the step of modulating a back pressure valve that is connected to an outlet of a cathode of said fuel cell stack to protect said fuel cell stack when said air compressor is run at said high airflow and high pressure.

22. The method of claim 19 further comprising the step of setting a brake torque of said regenerative braking device as a function of vehicle speed using a controller.

23. The method of claim 18 further comprising the step of interrupting delivery of air and fuel to said fuel cell stack when said vehicle is traveling downhill.

24. The method of claim 18 wherein said regenerative braking device is an electric traction system.

25. The method of claim 24 wherein said controller modulates said bypass valve.