Methods of operating a parallel hybrid vehicle

• US 20040178635A1
• Filed: 03/10/2003
• Published: 09/16/2004
• Est. Priority Date: 03/10/2003
• Status: Active Grant

• Current Assignee: Government of United States of America, As Represented by the Administrator of the U.S. Environmental Protection Agency
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Gray, Charles L. Jr.
• Granted Patent: US 6,998,727 B2
• Time in Patent Office: Days
• US Class Current: 290/40C
• CPC Class Codes: B60K 6/10 by means of a chargeable mechanical accumulator, e.g. flywheel
• CPC Class Codes: B60K 6/12 by means of a chargeable fluidic accumulator
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 7/16 for vehicles comprising converters between the power source and the motor
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

The invention is directed toward methods for operating a parallel hybrid vehicle in a manner that responds to the operator'"'"'s demand for power output, while maximizing engine efficiency and minimizing disruptions in vehicle drivability. According to principles of the present invention, when the driver of a hybrid vehicle makes a demand for power output immediately after a braking event, the power provided to meet the initial demand is from either an ICE or a secondary power source. Which power source is used, and when it is engaged and disengaged, depends on various vehicle operating conditions. Also, the ICE is selectively turned off and on in response to various operating conditions.

Claims

1. A method of operating a hybrid vehicle comprising:

monitoring a braking event;

monitoring an amount of available energy stored within an energy storage device to power a secondary power source;

detecting a demand for power output following the braking event;

utilizing the amount of available energy to initially power the secondary power source and thereby propel the vehicle in response to the demand for power output if the available energy is above a first selected level;

utilizing power provided by an ICE to continue meeting the demand for power output when the secondary power source is initially used and the amount of available energy is subsequently depleted; and

utilizing power provided by the ICE, instead of the secondary power source, to propel the vehicle in response to the demand for power output when the available energy is not above the first selected level.

2. The method according to claim 1 further comprising:

determining if the braking event indicates an intent to stop the vehicle; and

turning the ICE off when the braking event indicates an intent to stop the vehicle and the available energy to power the secondary power source is above a second selected level.

3. The method according to claim 2 further comprising:

restarting the ICE as soon as a command to brake the vehicle ceases to exist.

4. The method according to claim 2 further comprising:

restarting the ICE when the available energy is just enough to provide a specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

5. The method according to claim 2 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

6. The method according to claim 2 further comprising:

turning the ICE off when the braking event indicates an intent to stop the vehicle and the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

7. The method according to claim 6 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

8. The method according to claim 1 further comprising:

turning the ICE off when the demand for power output terminates and the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

9. The method according to claim 8 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

10. The method according to claim 8 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

11. The method according to claim 1 further comprising:

turning the ICE off when a command for braking begins if the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

12. The method according to claim 11 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

13. The method according to claim 11 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

14. The method according to claim 1 further comprising:

turning the ICE off when the vehicle'"'"'s speed falls below a first selected threshold and the available energy to power the secondary power source is above a second selected threshold.

15. The method according to claim 14 further comprising:

restarting the ICE when the available energy is just enough to provide a specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

16. The method according to claim 14 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

17. The method according to claim 1 further comprising:

monitoring the amount of available energy; and

comparing the amount of available energy to a table of pre-established torque and pre-established acceleration values to determine whether the amount of available energy is sufficient enough to provide a specified level of vehicle torque, or sufficient enough to provide a specified level of vehicle acceleration for a specified amount of time.

18. The method according to claim 17 wherein the amount of available energy is a unit of electric energy.

19. The method according to claim 17 wherein the amount of available energy is a unit of hydraulic pressure.

20. The method according to claim 1 further comprising:

monitoring an amount of reserve energy stored within the energy storage device;

determining when a demand for additional ICE power output will result in a transmission downshift event; and

utilizing the amount of reserve energy to power the secondary power source and provide supplemental power to the vehicle, the vehicle thereby being powered by both the ICE and the secondary power source until the demand for additional ICE power output is terminated or the amount of reserve energy is depleted.

21. A method of operating a hybrid vehicle comprising:

monitoring a braking event;

determining if the braking event indicates an intent to stop the vehicle;

monitoring an amount of available energy stored within an energy storage device to power a secondary power source;

detecting a demand for power output following the braking event;

utilizing the amount of available energy to initially power the secondary power source and thereby propel the vehicle in response to the demand for power output if the braking event indicates an intent to stop the vehicle;

utilizing power provided by an ICE to continue meeting the demand for power output when the secondary power source is initially used and the amount of available energy is subsequently depleted; and

utilizing power provided by the ICE, instead of the secondary power source, to propel the vehicle in response to the demand for power output when the braking event does not indicate an intent to stop the vehicle.

22. The method according to claim 21 further comprising:

turning the ICE off when the braking event indicates an intent to stop the vehicle and the available energy to power the secondary power source is above a selected level.

23. The method according to claim 22 further comprising:

restarting the ICE as soon as a command to brake the vehicle ceases to exist.

24. The method according to claim 22 further comprising:

restarting the ICE when the available energy is just enough to provide a specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

25. The method according to claim 22 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

26. The method according to claim 22 further comprising:

turning the ICE off when the braking event indicates an intent to stop the vehicle and the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

27. The method according to claim 26 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

28. The method according to claim 21 further comprising:

turning the ICE off when the demand for power output terminates and the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

29. The method according to claim 28 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

30. The method according to claim 28 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

31. The method according to claim 21 further comprising:

turning the ICE off when a command for braking begins if the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

32. The method according to claim 31 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

34. The method according to claim 21 further comprising:

turning the ICE off when the vehicle'"'"'s speed falls below a first selected threshold and the available energy to power the secondary power source is above a second selected threshold.

35. The method according to claim 34 further comprising:

restarting the ICE when the available energy is just enough to provide a specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

36. The method according to claim 34 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

37. The method according to claim 21 further comprising:

monitoring the amount of available energy; and

comparing the amount of available energy to a table of pre-established torque and pre-established acceleration values to determine whether the amount of available energy is sufficient enough to provide a specified level of vehicle torque, or sufficient enough to provide a specified level of vehicle acceleration for a specified amount of time.

38. The method according to claim 37 wherein the amount of available energy is a unit of electric energy.

39. The method according to claim 37 wherein the amount of available energy is a unit of hydraulic pressure.

40. The method according to claim 21 further comprising:

monitoring an amount of reserve energy stored within the energy storage device;

determining when a demand for additional ICE power output will result in a transmission downshift event; and

utilizing the amount of reserve energy to power the secondary power source and provide supplemental power to the vehicle, the vehicle thereby being powered by both the ICE and the secondary power source until the demand for additional ICE power output is terminated or the amount of reserve energy is depleted.

33. The method according to claim 33 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

41. A method of operating a hybrid vehicle comprising:

monitoring a braking event;

monitoring an amount of available energy stored within an energy storage device to power a secondary power source;

detecting a demand for power output following the braking event;

determining if the braking event indicates an intent to stop the vehicle;

utilizing the amount of available energy to initially power the secondary power source and thereby propel the vehicle in response to the demand for power output when the braking event indicates an intent to stop the vehicle or when the amount of available energy is sufficient enough to provide a minimum desired level of vehicle torque;

utilizing power provided by an ICE to continue meeting the demand for power output when the secondary power source is initially used and the amount of available energy is subsequently depleted; and

utilizing power provided by the ICE to propel the vehicle in response to the demand for power output when the braking event does not indicate an intent to stop the vehicle and the amount of available energy is not sufficient enough to provide the minimum desired level of vehicle torque.

42. The method according to claim 41 further comprising:

turning the ICE off when the braking event indicates an intent to stop the vehicle and the available energy to power the secondary power source is above a selected level.

43. The method according to claim 42 further comprising:

restarting the ICE as soon as a command to brake the vehicle ceases to exist.

44. The method according to claim 42 further comprising:

restarting the ICE when the available energy is just enough to provide a specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

45. The method according to claim 42 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

46. The method according to claim 42 further comprising:

turning the ICE off when the braking event indicates an intent to stop the vehicle and the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

47. The method according to claim 46 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

48. The method according to claim 41 further comprising:

turning the ICE off when the demand for power output terminates and the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

49. The method according to claim 48 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

50. The method according to claim 48 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

51. The method according to claim 41 further comprising:

turning the ICE off when a command for braking begins if the available energy to power the secondary power source is sufficient enough to provide a first specified level of vehicle acceleration for a specified amount of time.

52. The method according to claim 51 further comprising:

restarting the ICE when the available energy is just enough to provide a second specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

53. The method according to claim 51 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

54. The method according to claim 41 further comprising:

turning the ICE off when the vehicle'"'"'s speed falls below a first selected threshold and the available energy to power the secondary power source is above a second selected threshold.

55. The method according to claim 54 further comprising:

restarting the ICE when the available energy is just enough to provide a specified level of acceleration to the vehicle, through the secondary power source, for a specified amount of time.

56. The method according to claim 54 further comprising:

restarting the ICE when the demand for power output corresponds to a command to accelerate the vehicle above a predetermined threshold.

57. The method according to claim 41 further comprising:

monitoring the amount of available energy; and

comparing the amount of available energy to a table of pre-established torque and pre-established acceleration values to determine whether the amount of available energy is sufficient enough to provide a specified level of vehicle torque, or sufficient enough to provide a specified level of vehicle acceleration for a specified amount of time.

58. The method according to claim 57 wherein the amount of available energy is a unit of electric energy.

59. The method according to claim 57 wherein the amount of available energy is a unit of hydraulic pressure.

60. The method according to claim 41 further comprising:

monitoring an amount of reserve energy stored within the energy storage device;

determining when a demand for additional ICE power output will result in a transmission downshift event;

utilizing the amount of reserve energy to power the secondary power source and provide supplemental power to the vehicle, the vehicle thereby being powered by both the ICE and the secondary power source until the demand for additional ICE power is terminated or the amount of reserve energy is depleted.

61. A method of operating a hybrid vehicle comprising:

monitoring a braking event;

monitoring a first amount of energy stored within a first energy storage device to power a secondary power source;

detecting a demand for power output following the braking event;

utilizing the first amount of energy to power the secondary power source and thereby propel the vehicle after the braking event and in response to the demand for power output;

utilizing power provided by an ICE to continue meeting the demand for power output after the first amount of energy is depleted;

determining when a demand for additional power output exceeds a preselected level; and

utilizing a second amount of energy to power the secondary power source and provide supplemental power to the vehicle, the vehicle thereby being powered by both the ICE and the secondary power source until the demand for additional power output is terminated or until the second amount of energy is depleted.

62. The method according to claim 61 further comprising:

identifying a transmission downshift event resulting from the demand for additional power output.

63. The method according to claim 61 further comprising:

turning the ICE off during the braking event and restarting the ICE prior to utilizing power provided by the ICE.

64. The method according to claim 61 wherein the second amount of energy is stored within the first energy storage device.

65. The method according to claim 61 wherein the second amount of energy is stored within a second energy storage device.