Control system and method for a parallel hybrid electric vehicle

• US 20030098187A1
• Filed: 10/01/2001
• Published: 05/29/2003
• Est. Priority Date: 10/01/2001
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bailey, Kathleen Ellen, Phillips, Anthony Mark, Jankovic, Miroslava
• Granted Patent: US 6,735,502 B2
• Time in Patent Office: Days
• US Class Current: 180/65.25
• CPC Class Codes: B60K 6/48 Parallel 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 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 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/917 with transmission for changing gear ratio

Abstract

The present invention provides a control strategy for a parallel hybrid electric vehicle (HEV) configuration where power from the engine and the motor can each independently provide torque to the vehicle powertrain. The invention has a logical structure defining main system operating modes (states) and the transition between the different states. In addition to the predefined states, the present invention provides a set of rules defining logical relationships between each of the plurality of predefined states and a set of commands unique to each state. These commands are supplied to subsystem controllers to achieve desired vehicle functionality. The predefined states can be prioritized according to operator demands, energy management requirements, and system fault occurrences. The present invention can also be configured to have at least one of a plurality of transition flags. Each transition flag represents a logical relationship associated with efficient management of energy, operator demand, or system faults.

Claims

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

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

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

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

2. The controller of claim 1 wherein the plurality of predefined states representing operating modes are prioritized according to operator demands, energy management requirements, and system fault occurrences.

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

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

5. The controller of claim 1 wherein the set of rules further comprises at least one of a plurality of transition flags wherein each transition flag of the plurality of transition flags is representative of a logical relationship associated with operator demand, efficient management of energy and system faults.

6. The controller of claim 5 wherein the plurality of transition flags further comprises:

a BLEEDING_FLAG;

a BOOST_FLAG;

a BRAKE_SWITCH_FLAG;

a CHARGE_ENABLE_FLAG;

a CHARGE_FLAG;

a CHARGE_OFF_FLAG;

a CRANK_INH_FLAG;

a DISALLOW_BOOST_FLAG;

a DISALLOW_EN_MGT_FLAG;

an ENERGY_MGT_FLAG

an ENG_ON_FLAG;

an ENG_RESTART_OK_FLAG;

an ENG_STARTED_FLAG;

an ENG_STOPPED_FLAG;

a FLG_SHIFTIN_FLAG;

an IDLE_CRANK_FLAG;

an L_FLAG;

a KEY_CRANK_FLAG;

a KEY_OFF_FLAG;

a KEY_ON_FLAG;

a MAX_SOURCE_CURRENT_ZERO_FLAG;

a REGEN_FLAG;

an SA_DISABLED_FLAG;

a STALL_FLAG;

a TRANS_ENGAGED_FLAG; and

a VS_ENG_DRV_FLAG

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

7. The controller of claim 6 wherein the plurality of predefined states representing operating modes are defined as BLEED state, BOOST state, CHARGE state, REGEN LOW VEL state, REGEN HIGH VEL state, ENGINE DRIVE state, ENGINE START state, ENGINE STOP state, MOTOR DRIVE state, and OFF state.

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

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

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

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

9. The method of claim 8 further comprising the step of prioritizing the plurality of states based on operator demands, system fault occurrences, and energy management requirements.

10. The method of claim 8 wherein the step of prioritizing the plurality of states further comprises the steps of:

defining the system fault occurrences as a first level priority;

defining the operator demands as a second level priority; and

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

11. The method of claim 8 wherein the step of prioritizing the plurality of states further comprises the steps of:

defining the system fault occurrences as a first level priority;

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

defining the operator demands as a third level of priority.

12. The method of claim 8 wherein the step of defining a set of rules further comprises the step of defining a plurality of transition flags, each of the transition flags being representative of a logical relationship associated with operator demand, efficient management of energy and system faults.

13. The method of claim 12 wherein the step of defining a plurality of transition flags further comprises defining:

a BLEEDING_FLAG;

a BOOST_FLAG;

a BRAKE_SWITCH_FLAG;

a CHARGE_ENABLE_FLAG;

a CHARGE_FLAG;

a CHARGE_OFF FLAG;

a CRANK_INH_FLAG;

a DISALLOW_BOOST_FLAG;

a DISALLOW_EN_MGT_FLAG;

an ENERGY_MGT_FLAG

an ENG_ON_FLAG;

an ENG_RESTART_OK_FLAG;

an ENG_STARTED_FLAG;

an ENG_STOPPED_FLAG;

a FLG_SHIFTIN_FLAG;

an IDLE_CRANK_FLAG;

an L_FLAG;

a KEY_CRANK_FLAG;

a KEY_OFF_FLAG;

a KEY_ON_FLAG;

a MAX_SOURCE_CURRENT_ZERO_FLAG;

a REGEN_FLAG;

an SA_DISABLED_FLAG;

a STALL_FLAG;

a TRANS_ENGAGED; and

a VS_ENG_DRV_FLAG

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

14. The method of claim 13 wherein the step of defining a plurality of states further comprises defining a BLEED state, BOOST state, CHARGE state, REGEN LOW VEL state, REGEN HIGH VEL state, ENGINE DRIVE state, ENGINE START state, ENGINE STOP state, MOTOR DRIVE state, and OFF state.