Control system and method for a hybrid electric vehicle

• US 6,321,143 B1
• Filed: 06/26/2000
• Issued: 11/20/2001
• Est. Priority Date: 06/26/2000
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Phillips, Anthony Mark, Jankovic, Miroslava, Bailey, Kathleen Ellen, Blankenship, John Richard
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Donnelly, Arthur D.
• Application Number:
  US09/603,165
• Time in Patent Office: 512 Days
• Field of Search: 701/22, 701/54, 180/65.2, 180/165, 475/5, 477/2, 318/139
• US Class Current: 701/22
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/54 Transmission for changing ratio
• 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 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2050/021 Means for detecting failure or malfunction
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/917 with transmission for changing gear ratio

Abstract

A vehicle system controller (20) is presented for a LSR parallel hybrid electric vehicle having an engine (10), a motor (12), wheels (14), a transmission (16) and a battery (18). The vehicle system controller (20) has a state machine having a plurality of predefined states (22-32) that represent operating modes for the vehicle. A set of rules is defined for controlling the transition between any two states in the state machine. The states (22-32) are prioritized according to driver demands, energy management concerns and system fault occurrences. The vehicle system controller (20) controls the transitions from a lower priority state to a higher priority state based on the set of rules. In addition, the vehicle system controller (20) will control a transition to a lower state from a higher state when the conditions no longer warrant staying in the current state. A unique set of output commands is defined for each state for the purpose of controlling lower level subsystem controllers. These commands serve to achieve the desire vehicle functionality within each state and insure smooth transitions between states.

Claims

1. A vehicle system controller for a LSR parallel hybrid electric vehicle having subsystem controllers, said vehicle system controller comprising:

a state machine having a plurality of predefined states representing operating modes of said vehicle;

a set of rules defining logical relationships between each of said plurality of predefined states; and

a set of commands unique to each state supplied to said subsystem controllers to achieve desired vehicle functionality within the states and to transition between said plurality of predefined states.

2. The controller as claimed in claim 1 wherein said plurality of predefined states representing operating modes are prioritized according to system fault occurrences, driver demands, and energy management requirements.

3. The controller as claimed in claim 2 wherein said system fault occurrences are defined as a first priority, driver demands are a second priority, and energy demands are a third priority.

4. The controller as claimed in claim 2 wherein said system fault occurrences are defined as a first priority, said energy demands are a second priority in the event system performance is being compromised, and driver demands are a third priority.

5. The controller as claimed in claim 1 wherein said set of rules further comprises at least one of a plurality of transition flags wherein each transition flag of said plurality of transition flags is representative of a logical relationship associated with sensed vehicle operating status, driver demand, or system faults.

6. The controller as claimed in claim 5 wherein said plurality of transition flags further comprises:

a REQUEST_STOP_FLAG;

an ENGINE_STARTED_OKAY_FLAG;

a BLEED_FLAG;

a BOOST_FLAG;

a CHARGE_FLAG;

a REGEN_FLAG;

a MOTOR_FAULT_FLAG;

a BATTERY_FAULT_FLAG; and

each of said plurality of transition flags are true and false depending on the current vehicle operating status, driver demand, and system fault status.

7. The controller as claimed in claim 6 wherein said plurality of predefined states representing operating modes are defined as a start/stop state, a boost state, a bleed state, a regen state, a charge state and a run state.

8. The controller as claimed in claim 7 wherein said plurality of predefined states are prioritized from highest priority to lowest priority as start/stop, boost, bleed, regen, charge and run.

9. The controller as claimed in claim 8 wherein said run state is defined as a default state for said state machine.

10. The controller as claimed in claim 9 wherein said set of commands controls a transition to said start/stop state from any one of said plurality of states for said set of rules comprising said REQUEST_STOP_FLAG transition flag is true.

11. The controller as claimed in claim 9 wherein said set of commands controls a transition from said start/stop state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG transition flag is false AND said ENGINE_STARTED_OKAY_FLAG is true.

12. The controller as claimed in claim 9 wherein said set of commands controls a transition from said bleed state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is false; and

at least one of the following is true;

said BLEED_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

13. The controller as claimed in claim 9 wherein said set of commands controls a transition from said run state to said bleed state for said set of rules comprising:

said BLEED_FLAG is true;

said MOTOR_FAULT_FLAG is false;

said BATTERY_FAULT_FLAG is false;

said REQUEST—

STOP_FLAG is false; and

said BOOST_FLAG is false.

14. The controller as claimed in claim 9 wherein said set of commands controls a transition from said boost state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false; and

at least one of the following is true;

said BOOST_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

15. The controller as claimed in claim 9 wherein said set of commands controls a transition from said run state to said boost state for said set of rules comprising:

said BOOST_FLAG is true;

said MOTOR_FAULT_FLAG is false;

said BATTERY_FAULT_FLAG is false; and

said REQUEST—

STOP_FLAG is false.

16. The controller as claimed in claim 9 wherein said set of commands controls a transition from said bleed state to said boost state for said set of rules comprising:

said REQUEST<sub>—

STOP</sub>_FLAG is false;

said BOOST_FLAG is true;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

17. The controller as claimed in claim 9 wherein said set of commands controls a transition from said charge state to said boost state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is true;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

18. The controller as claimed in claim 9 wherein said set of commands controls a transition from said run state to said charge state for said set of rules comprising:

said CHARGE_FLAG is true;

said MOTOR_FAULT_FLAG is false;

said BATTERY_FAULT_FLAG is false;

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is false; and

said REGEN_FLAG is false.

19. The controller as claimed in claim 9 wherein said set of commands controls a transition from said charge state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said REGEN_FLAG is false;

said BOOST_FLAG is false; and

at least one of the following is true;

said CHARGE_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

20. The controller as claimed in claim 9 wherein said set of commands controls a transition from said charge state to said regen state for said set of rules comprising:

said REGEN_FLAG is true;

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is false;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

21. The controller as claimed in claim 9 wherein said set of commands controls a transition from said regen state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false; and

at least one of the following is true;

said REGEN_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

22. The controller as claimed in claim 9 wherein said set of commands controls a transition from said run state to said regen state for said set of rules comprising:

said REGEN_FLAG is true;

said REQUEST_STOP_FLAG is false;

said BLEED_FLAG is false;

said BOOST_FLAG is false;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

23. A method for controlling a LSR parallel hybrid electric vehicle having subsystem controllers, said method comprising the steps of:

defining a plurality of states in a state machine wherein each of said plurality of states represents an operating mode for said vehicle;

defining a set of rules representing logical relationships between each of said plurality of states; and

supplying a set of commands unique to each state to said subsystem controllers to achieve desired vehicle functionality within the states and to transition between said plurality of states.

24. The method as claimed in claim 23 further comprising the step of prioritizing said plurality of states based on driver demands, system fault occurrences and energy management requirements.

25. The method as claimed in claim 24 wherein said step of prioritizing said plurality of states further comprises the steps of:

defining said system fault occurrences as a first level of priority;

defining said driver demands as a second level of priority; and

defining said energy management occurrences as a third level of priority.

26. The method as claimed in claim 24 wherein said step of prioritizing said plurality of states further comprises the steps of:

defining said system fault occurrences as a first level of priority;

defining said energy management occurrences as a second level of priority in the event vehicle performance is being compromised; and

defining said driver demands as a third level of priority.

27. The method as claimed in claim 23 wherein said step of defining a set of rules further comprises the step of defining a plurality of transition flags, each of said transition flags being representative of a logical relationship associated with sensed vehicle operating status, driver demand, or system faults.

28. The method as claimed in claim 27 wherein said step of defining a plurality of transition flags further comprises defining a REQUEST_STOP_FLAG, an ENGINE_STARTED_OKAY_FLAG, a BLEED_FLAG, a BOOST_FLAG, a CHARGE_FLAG, a REGEN_FLAG, a MOTOR_FAULT_FLAG, and a BATTERY_FAULT_FLAG, wherein each of said flags are true and false depending on the current vehicle operating status, driver demand, and system fault status.

29. The method as claimed in claim 28 wherein said step of defining a plurality of states further comprises defining a start/stop state, a boost state, a bleed state, a regen state, a charge state and a run state.

30. The method as claimed in claim 29 further comprising the step of prioritizing said states from highest priority to lowest priority as start/stop, boost, bleed, regen, charge and run.

31. The method as claimed in claim 29 further comprising the step of defining the run state to be a default state.

32. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition to said start/stop state from any one of said plurality of states for said REQUEST_STOP_FLAG transition flag being true.

33. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said start/stop state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG transition flag is false AND said ENGINE_STARTED_OKAY_FLAG is true.

34. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said bleed state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is false; and

at least one of the following is true;

said BLEED_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

35. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said run state to said bleed state for said set of rules comprising:

said BLEED_FLAG is true;

said MOTOR_FAULT_FLAG is false;

said BATTERY_FAULT_FLAG is false;

said REQUEST-STOP_FLAG is false; and

said BOOST_FLAG is false.

36. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said boost state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false; and

at least one of the following is true;

said BOOST_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

37. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said run state to said boost state for said set of rules comprising:

said BOOST_FLAG is true;

said MOTOR_FAULT_FLAG is false;

said BATTERY_FAULT_FLAG is false; and

said REQUEST_STOP_FLAG is false.

38. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said bleed state to said boost state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is true;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

39. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said charge state to said boost state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is true;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

40. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said run state to said charge state for said set of rules comprising:

said CHARGE_FLAG is true;

said MOTOR_FAULT_FLAG is false;

said BATTERY_FAULT_FLAG is false;

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is false; and

said REGEN_FLAG is false.

41. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said charge state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false;

said REGEN_FLAG is false;

said BOOST_FLAG is false; and

at least one of the following is true;

said CHARGE_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

42. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said charge state to said regen state for said set of rules comprising:

said REGEN_FLAG is true;

said REQUEST_STOP_FLAG is false;

said BOOST_FLAG is false;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.

43. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said regen state to said run state for said set of rules comprising:

said REQUEST_STOP_FLAG is false; and

at least one of the following is true;

said REGEN_FLAG is false, said MOTOR_FAULT_FLAG is true, or said BATTERY_FAULT_FLAG is true.

44. The method as claimed in claim 31 wherein said step of supplying a set of commands further comprises supplying a set of commands for a transition from said run state to said regen state for said set of rules comprising:

said REGEN_FLAG is true;

said REQUEST_STOP_FLAG is false;

said BLEED_FLAG is false;

said BOOST_FLAG is false;

said MOTOR_FAULT_FLAG is false; and

said BATTERY_FAULT_FLAG is false.