Control system for a hybrid electric vehicle to anticipate the need for a mode change

• US 7,753,150 B2
• Filed: 05/22/2008
• Issued: 07/13/2010
• Est. Priority Date: 10/11/2000
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Tamor, Michael A.
• Primary Examiner(s): Morris; Lesley
• Assistant Examiner(s): WALTERS, JOHN DANIEL
• Application Number:
  US12/125,101
• Publication Number:
  US 20080224478A1
• Time in Patent Office: 782 Days
• Field of Search: 180/65.21, 180/65.265, 180/65.27, 180/65.275, 180/65.28, 180/65.285, 180/65.29, 903/930, 903/947, 701/22
• US Class Current: 180/65.265
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2530/10 Weight
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/106 Rate of change
• 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: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/947 Characterized by control of braking, e.g. blending of regeneration, friction braking

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 and electromotive driving by monitoring vehicle speed and driver commands 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 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 zone 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 zone, when the maximum power capability of the drive unit is reached whereby the engine is started to effect a smooth power transition between the second and intermediate 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 calculated time before the maximum power capability of the drive unit is reached with the powertrain operating in the intermediate operating zone.

2. The hybrid electric vehicle set forth in claim 1 wherein the powertrain 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.

3. The hybrid electric vehicle set forth in claim 1 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

4. The hybrid electric vehicle set forth in claim 1 wherein the powertrain operating variables include road grade.

5. The hybrid electric vehicle set forth in claim 1 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

6. The hybrid electric vehicle set forth in claim 1 wherein the powertrain operating variables include road grade.

7. 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 drive unit power delivery within a maximum drive unit 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 drive unit 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, the engine being started at a calculated time within the intermediate operating region relative to the instant when the maximum power capability of the drive unit is reached during a transition between the power delivery operating zones.

8. The hybrid electric vehicle set forth in claim 7 wherein the powertrain 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.

9. The hybrid electric vehicle set forth in claim 8 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.

10. A hybrid electric vehicle powertrain having a vehicle brake pedal, 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 zone 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 zone, when the maximum power capability of the battery is reached whereby the engine is started to effect a smooth power transition between the intermediate and second power delivery operating zones;

the powertrain control system responding to operating variables including 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.

11. The hybrid electric vehicle set forth in claim 10 wherein the powertrain operating variables include vehicle speed and rate of vehicle acceleration.

12. The hybrid electric vehicle set forth in claim 10 wherein the powertrain operating variables include road grade.

13. 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;

and

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 with a maximum power capability threshold, 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 zone in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

the controller being configured for anticipating an instant, during operation in the intermediate zone, when the maximum power capability threshold for the drive unit is reached whereby the engine may be started to effect a smooth power transition between the intermediate and second 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, the engine being started at a calculated time before the maximum power capability threshold for the drive unit is reached with the powertrain operating in the intermediate operating zone and whereby the engine is stopped in the intermediate operating zone at a calculated time when a power capability lower threshold for the drive unit is reached following operation of the powertrain in the second operating zone.

14. The hybrid electric vehicle set forth in claim 13 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.

15. 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 adapted to respond to powertrain operating to turn off the engine to effect power delivery solely from the battery and to turn 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 drive unit power delivery, 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 zone in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

the control system being configured for anticipating an engine start at an instant before the maximum power capability of the drive unit is reached during a transition between the intermediate and second power delivery operating zones;

the powertrain control system having a vehicle brake pedal driver input brake pedal-controlled vehicle brakes and responding to a rate of change of brake pedal force, the engine being stopped at a calculated time within the intermediate operating zone when a transition is made between the intermediate and first operating zones.

16. The hybrid electric vehicle set forth in claim 15 wherein the powertrain comprises a planetary gear unit and the electric drive unit comprises a battery, 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;

the motor being drivably connected to the vehicle traction wheels.

17. 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, a 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 power capability upper threshold, 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 zone with a lower power capability threshold in which the drive unit operates with reduced efficiency and the engine may be started to develop driving torque; and

the control system being configured for anticipating an instant, during operation in the intermediate zone, when the power capability upper threshold for the drive unit is reached whereby the engine is started to effect a smooth power transition between the intermediate and second 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 may be started at a calculated time before the power capability upper threshold for the drive unit is reached with the powertrain operating in the intermediate operating zone and whereby the engine is stopped in the intermediate operating zone when the power capability lower threshold for the battery is reached following operation in the second operating zone during a transition from the second operating zone.

18. The hybrid electric vehicle set forth in claim 17 wherein the powertrain comprises a planetary gear unit and the electric drive unit comprises a battery, 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;

the motor being drivably connected to the vehicle traction wheels.

19. 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 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 below a maximum power capability threshold for the first operating zone, the engine having a power delivery second operating zone characterized by high efficiency engine power delivery;

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

the controller being configured for anticipating an instant, during operation in the intermediate zone, when the maximum power capability threshold of the drive unit is reached whereby the engine is started to effect a smooth power transition between the intermediate and second power delivery operating zones;

the powertrain control system responding to operating variables including accelerator pedal position and brake pedal force whereby the engine may be started at a calculated time before the maximum power capability threshold for the drive unit is reached.