CONTROL SYSTEM FOR A HYBRID ELECTRIC VEHICLE TO ANTICIPATE THE NEED FOR A MODE CHANGE

• US 20050211479A1
• Filed: 05/18/2005
• Published: 09/29/2005
• Est. Priority Date: 10/11/2000
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Tamor, Michael
• Granted Patent: US 7,407,026 B2
• Time in Patent Office: Days
• US Class Current: 180/65.250
• CPC Class Codes: B60K 6/48 Parallel type
• 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 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: F02D 2041/1411 using a finite or infinite state machine, automaton or state graph for controlling or modelling
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: F02N 2200/101 Accelerator pedal position
• CPC Class Codes: F02N 2200/102 Brake pedal position
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A parallel hybrid electric vehicle method and system including an internal combustion engine (ICE), an electric traction motor/generator, and a controller. A control strategy is provided to prevent unpredicted or undesired engine starts by anticipating the need for the vehicle engine, while avoiding “false starting” the engine or allowing an annoying lag in performance that will occur if the engine is not started in advance of an actual requirement. The invention anticipates the need for engine starts by monitoring vehicle speed and driver demand and their rates of change. The invention allows consistent performance and establishes seamless transitions between engine driving and electromotive driving.

Claims

1. A hybrid electric vehicle with a powertrain having an internal combustion engine with an accelerator pedal and a throttle controlled by a vehicle system controller that responds to accelerator pedal movement, the vehicle including a powertrain control system, an electric drive unit, and a battery electrically connected to the drive unit for powering the same;

the powertrain control system being electronically coupled to the vehicle system controller and including an engine speed and torque control and a drive unit speed and torque control whereby engine and drive unit on and off states are effected;

the powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning on the engine to effect power delivery selectively by the engine solely and by the battery and engine working together;

the drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

means for anticipating an instant when a battery power limit is reached;

the powertrain control system comprising further accelerator pedal movement driver input from the vehicle system controller and means for measuring a rate of change of accelerator pedal position; and

means for responding to a measured rate of change of accelerator pedal position for starting the engine at a calculated time before the battery power limit is reached, thereby effecting a smooth power delivery transition from the battery to the engine.

8. The hybrid electric vehicle set forth in claim 1 including engine brake means for anchoring a power output member for the engine when the engine is in an engine off state.

10. The hybrid electric vehicle set forth in claim 1 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element driveably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

2. A hybrid electric vehicle powertrain having an internal combustion engine with an accelerator pedal and a throttle controlled by a vehicle system controller that responds to accelerator pedal movement, an electric drive unit and a battery electrically connected to the drive unit for powering the drive unit,

a powertrain control system comprising means for measuring rate of change of accelerator pedal position, the powertrain control system being electronically coupled to the vehicle system controller and including an engine speed and torque control and a drive unit speed and torque control whereby engine on and off states and drive unit on and off states are effected;

the powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning on the engine to effect power delivery selectively by the engine solely and by the engine and battery working together;

the electric drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

means for anticipating an instant when a battery power limit is reached; and

means responding to powertrain operating variables including rate of change of accelerator pedal position for changing the operating state of the engine at a calculated time relative to the instant when the battery power limit is reached during a transition between the power delivery operating zones thereby effecting a smooth power delivery transition.

9. The control system set forth in claim 2 including an engine brake means for anchoring a power output member for the engine when the engine is in an engine off state.

11. The hybrid electric vehicle set forth in claim 2 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

16. The hybrid electric vehicle set forth in claim 2 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

17. The hybrid electric vehicle set forth in claim 2 wherein the powertrain operating variables include road grade.

3. A method for controlling a powertrain for a hybrid electric vehicle, the vehicle having vehicle wheel brakes, the powertrain having an internal combustion engine with an accelerator pedal and a throttle controlled by a vehicle system controller that responds to accelerator pedal movement, vehicle wheel brakes, an electric motor/generator drive unit, a driver operated brake pedal for controlling regenerative drive unit braking and for applying the vehicle wheel brakes, and a battery electrically connected to the drive unit for powering the same, the method comprising the steps of:

controlling engine speed and torque and drive unit speed and torque, within a maximum drive unit power capability, in response to engine throttle position whereby power values for the drive unit are within a first speed and torque operating zone characterized by high efficiency drive unit power delivery and power values for the engine are within a second speed and torque operating zone characterized by high efficiency engine power delivery;

turning off the engine to effect power delivery solely by the battery;

turning off the drive unit to effect power delivery solely by the engine;

establishing regenerative drive unit braking power in a regenerative braking operating zone in response to driver operated brake pedal force and rate of change of brake pedal force;

anticipating, upon changes in speed and torque, as brake pedal force and rate of brake pedal force change, a power limit for the regenerative braking operating zone; and

applying the vehicle wheel brakes to complement regenerative braking as the regenerative braking zone power limit is approached.

4. A hybrid electric vehicle with a powertrain having an internal combustion engine with an accelerator pedal and a throttle controlled by a vehicle system controller that responds to accelerator pedal movement, an electric drive unit, a battery electrically connected to the drive unit for powering the same;

a powertrain control system electronically coupled to the vehicle system controller and including an engine speed and torque control and a drive unit speed and torque control whereby engine on and off states are effected;

the powertrain control system including means for measuring rate of change of accelerator pedal position, means for turning off the engine to effect power delivery solely from the battery, and means for turning on the engine to effect power delivery selectively by the engine solely and by the engine and battery working together;

the drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the drive unit having an intermediate power delivery operating region in which the drive unit operates with reduced efficiency and in which the engine may be started to develop driving torque while the powertrain operates in the intermediate region; and

means responsive to measured rate of change of accelerator pedal position for anticipating an instant during operation in the intermediate region when the maximum power capability of the battery is approached and for starting the engine as the power delivery second operating zone is entered, thereby effecting a smooth power transition from the intermediate power delivery operating region to the power delivery second operating zone.

12. The hybrid electric vehicle set forth in claim 4 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

5. A hybrid electric vehicle with vehicle wheel brakes, a driver actuated accelerator pedal and a driver actuated brake pedal, a powertrain having an internal combustion engine with a throttle controlled by a vehicle system controller that responds to accelerator pedal driver input and to brake pedal driver input, an electric drive unit, and a battery electrically connected to the drive unit for powering the drive unit;

a powertrain control system electrically coupled to the vehicle system controller including means for turning off the engine to effect power delivery solely from the battery and means for turning on the engine to effect power delivery selectively by the engine solely and by the engine and battery working together;

the drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the drive unit having an intermediate operating region in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

means for anticipating an instant when the maximum power capability of the battery is reached during a transition between the first and second power delivery operating zones;

the powertrain control system including a brake pedal driver input from the vehicle system controller and responding to a rate of change of brake pedal force whereby the engine is started at a calibrated time within the intermediate operating region relative to the instant when the battery power limit is reached during a transition between the power delivery operating zones.

13. The hybrid electric vehicle set forth in claim 5 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

6. A hybrid electric vehicle with a powertrain having an internal combustion engine with an accelerator pedal and a throttle controlled by a vehicle system controller that responds to accelerator pedal movement, an electric drive unit, a battery electrically connected to the drive unit for powering the drive unit;

a powertrain control system electronically coupled to the vehicle system controller and including an engine speed and torque control and a drive unit speed and torque control whereby engine on and off states and drive unit on and off states are effected;

the powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning off the drive unit to effect power delivery selectively by the engine solely and by the engine and battery working together;

the electric drive unit having a power delivery first operating zone characterized by high efficiency delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the electric drive unit having an intermediate power delivery operating region in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

means for anticipating an instant, during operation in the intermediate region, when the maximum power capability of the battery is reached whereby the engine state is changed to effect a smooth power transition from the first to the second power delivery speed and torque operating zones;

the powertrain control system responding to powertrain operating variables including rate of change of accelerator pedal position.

14. The hybrid electric vehicle set forth in claim 6 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

18. The hybrid electric vehicle set forth in claim 6 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

19. The hybrid electric vehicle set forth in claim 6 wherein the powertrain operating variables include road grade.

7. A hybrid electric vehicle powertrain having an internal combustion engine with an accelerator pedal and a throttle controlled by a vehicle system controller that responds to accelerator pedal movement and vehicle brake pedal movement, an electric drive unit, a battery electrically connected to the drive unit for powering the electric drive unit;

a powertrain control system electrically coupled to the vehicle system controller including an engine speed and torque control, a drive unit speed and torque control and means for measuring rates of change of accelerator pedal position and vehicle brake pedal force whereby engine on and off states and drive unit on and off states are effected;

the drive unit having a power delivery first operating zone characterized by high efficiency drive unit power delivery within a maximum power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the drive unit having an intermediate power delivery operating region in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

means for anticipating an instant, during operation in the intermediate region, when the maximum power capability of the battery is reached whereby the engine is started to effect a smooth power transition between the power delivery operating zones;

the powertrain control system including a brake pedal driver input, the control system responding to operating variables including a rate of change of brake pedal force and a rate of change of accelerator pedal position whereby the engine is started at a calibrated time before the maximum power capability of the battery is reached with the powertrain operating in the intermediate operating region.

15. The hybrid electric vehicle set forth in claim 7 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

20. The hybrid electric vehicle set forth in claim 7 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

21. The hybrid electric vehicle set forth in claim 7 wherein the powertrain operating variables include road grade.

22. A hybrid electric vehicle with a powertrain having a throttle-controlled internal combustion engine with an accelerator pedal and a throttle that responds to accelerator pedal movement, the vehicle including a powertrain control system, an electric drive unit, and a battery electrically connected to the drive unit for powering the same;

the powertrain control system including an engine speed and torque control and a drive unit speed and torque control whereby engine and drive unit on and off states are effected;

the powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning on the engine to effect power delivery selectively by the engine solely and by the battery and engine working together;

the drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

means for anticipating an instant when a battery power limit is reached;

the powertrain control system comprising further accelerator pedal movement driver input from the vehicle system controller and means for measuring a rate of change of accelerator pedal position; and

means for responding to a measured rate of change of accelerator pedal position for starting the engine at a calculated time before the battery power limit is reached, thereby effecting a smooth power delivery transition from the battery to the engine.

28. The hybrid electric vehicle set forth in claim 22 including engine brake means for anchoring a power output member for the engine when the engine is in an engine off state.

30. The hybrid electric vehicle set forth in claim 22 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element driveably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

23. A hybrid electric vehicle powertrain having a throttle-controlled internal combustion engine with an accelerator pedal and a throttle that responds to accelerator pedal movement and an electric drive unit and a battery electrically connected to the drive unit for powering the drive unit,

a powertrain control system comprising means for measuring rate of change of accelerator pedal position, including an engine speed and torque control and a drive unit speed and torque control whereby engine on and off states and drive unit on and off states are effected;

the powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning on the engine to effect power delivery selectively by the engine solely and by the engine and battery working together;

the electric drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

means for anticipating an instant when a battery power limit is reached; and

means responding to powertrain operating variables including rate of change of accelerator pedal position for changing the operating state of the engine at a calculated time relative to the instant when the battery power limit is reached during a transition between the power delivery operating zones thereby effecting a smooth power delivery transition.

29. The control system set forth in claim 23 including an engine brake means for anchoring a power output member for the engine when the engine is in an engine off state.

31. The hybrid electric vehicle set forth in claim 23 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

36. The hybrid electric vehicle set forth in claim 23 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

37. The hybrid electric vehicle set forth in claim 23 wherein the powertrain operating variables include road grade.

24. A hybrid electric vehicle with a powertrain having a throttle-controlled internal combustion engine with an accelerator pedal and a throttle that responds to accelerator pedal movement, an electric drive unit, a battery electrically connected to the drive unit for powering the same;

a powertrain control system including an engine speed and torque control and a drive unit speed and torque control whereby engine on and off states are effected;

the powertrain control system including means for measuring rate of change of accelerator pedal position, means for turning off the engine to effect power delivery solely from the battery, and means for turning on the engine to effect power delivery selectively by the engine solely and by the engine and battery working together;

the drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the drive unit having an intermediate power delivery operating region in which the drive unit operates with reduced efficiency and in which the engine may be started to develop driving torque while the powertrain operates in the intermediate region; and

means responsive to measured rate of change of accelerator pedal position for anticipating an instant during operation in the intermediate region when the maximum power capability of the battery is approached and for starting the engine as the power delivery second operating zone is entered, thereby effecting a smooth power transition from the intermediate power delivery operating region to the power delivery second operating zone.

32. The hybrid electric vehicle set forth in claim 24 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

25. A hybrid electric vehicle with vehicle wheel brakes, a powertrain having a throttle-controlled internal combustion engine with an accelerator pedal and a throttle that responds to accelerator pedal driver input, an electric drive unit, and a battery electrically connected to the drive unit for powering the drive unit;

a powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning on the engine to effect power delivery selectively by the engine solely and by the engine and battery working together;

the drive unit having a power delivery first operating zone characterized by high efficiency battery power delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the drive unit having an intermediate operating region in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

means for anticipating an instant when the maximum power capability of the battery is reached during a transition between the first and second power delivery operating zones;

the powertrain control system having a vehicle brake pedal driver input including brake pedal-controlled vehicle brakes, the powertrain control system including a brake pedal driver input and responding to a rate of change of brake pedal force whereby the engine is started at a calibrated time within the intermediate operating region relative to the instant when the battery power limit is reached during a transition between the power delivery operating zones.

33. The hybrid electric vehicle set forth in claim 25 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

26. A hybrid electric vehicle with a powertrain having a throttle-controlled internal combustion engine with an accelerator pedal and a throttle that responds to accelerator pedal movement, an electric drive unit, a battery electrically connected to the drive unit for powering the drive unit;

a powertrain control system including an engine speed and torque control and a drive unit speed and torque control whereby engine on and off states and drive unit on and off states are effected;

the powertrain control system including means for turning off the engine to effect power delivery solely from the battery and means for turning off the drive unit to effect power delivery selectively by the engine solely and by the engine and battery working together;

the electric drive unit having a power delivery first operating zone characterized by high efficiency delivery within a maximum battery power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the electric drive unit having an intermediate power delivery operating region in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

means for anticipating an instant, during operation in the intermediate region, when the maximum power capability of the battery is reached whereby the engine state is changed to effect a smooth power transition from the first to the second power delivery speed and torque operating zones;

the powertrain control system responding to powertrain operating variables including rate of change of accelerator pedal position.

34. The hybrid electric vehicle set forth in claim 26 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

38. The hybrid electric vehicle set forth in claim 26 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

39. The hybrid electric vehicle set forth in claim 26 wherein the powertrain operating variables include road grade.

27. A hybrid electric vehicle powertrain having a throttle-controlled internal combustion engine with an accelerator pedal and a throttle that responds to accelerator pedal movement and vehicle brake pedal movement, an electric drive unit, a battery electrically connected to the drive unit for powering the electric drive unit;

a powertrain control system including an engine speed and torque control, a drive unit speed and torque control and means for measuring rates of change of accelerator pedal position and vehicle brake pedal force whereby engine on and off states and drive unit on and off states are effected;

the drive unit having a power delivery first operating zone characterized by high efficiency drive unit power delivery within a maximum power capability, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

the engine and the drive unit having an intermediate power delivery operating region in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

means for anticipating an instant, during operation in the intermediate region, when the maximum power capability of the battery is reached whereby the engine is started to effect a smooth power transition between the power delivery operating zones;

the powertrain control system including a brake pedal driver input, the control system responding to operating variables including a rate of change of brake pedal force and a rate of change of accelerator pedal position whereby the engine is started at a calibrated time before the maximum power capability of the battery is reached with the powertrain operating in the intermediate operating region.

35. The hybrid electric vehicle set forth in claim 27 wherein the power transmission comprises a planetary gear unit and the electric drive unit comprises a generator and a motor;

the planetary gear unit having a first element drivably connected to the generator, a second element drivably connected to the vehicle traction wheels and a third element drivably connected to the engine; and

the motor being drivably connected to the vehicle traction wheels.

40. The hybrid electric vehicle set forth in claim 27 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

41. The hybrid electric vehicle set forth in claim 27 wherein the powertrain operating variables include road grade.