Control system for hybrid vehicle

• US 20020170758A1
• Filed: 05/14/2002
• Published: 11/21/2002
• Est. Priority Date: 05/18/2001
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Takizawa, Kazuaki, Hagiwara, Kenji, Shimabukuro, Eijiro
• Granted Patent: US 6,823,954 B2
• Time in Patent Office: Days
• US Class Current: 180/65.2
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/16 DC brushless machines
• CPC Class Codes: B60L 2240/14 Acceleration
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/485 Temperature
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• 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 2510/0604 : Throttle position
• CPC Class Codes: B60W 2510/0638 : Engine speed
• CPC Class Codes: B60W 2510/081 : Speed
• CPC Class Codes: B60W 2510/107 : Temperature
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2710/023 : Clutch engagement rate
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: F16H 61/0021 : Generation or control of line pressure
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/918 : Continuously variable
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

In a hybrid vehicle control system equipped with an internal combustion engine (10), an electric motor (14) connected to the engine through a hydraulic clutch (12) and an automatic transmission (16) connected to the motor to be inputted with an output torque outputted from the engine and the motor to transmit the same to driven wheels (24) of the vehicle, the output torque of the motor (TM) and supply of hydraulic pressure to the clutch (PCL) is increased until the determined speed difference (dN) is less than a threshold value (dN3) and then the output torque of the engine is reduced such that the engine speed (NE) is synchronized with the motor speed (NM) when the speed difference (dN) becomes less than the predetermined value (dN3), while increasing the supply of hydraulic pressure to a line pressure equivalent value. With this, it can effectively reduces shock at clutch engagement during switchover from electric motor-powered driving to internal combustion engine-powered driving.

Claims

1. A system for controlling a hybrid vehicle equipped with an internal combustion engine, an electric motor connected to an output shaft of the engine through a hydraulic clutch and an automatic transmission connected to an output shaft of the motor to be inputted with an output torque outputted from at least one of the engine and the motor to transmit the output torque to driven wheels of the vehicle, comprising:

initial control conducting means for conducting an initial control to supply priming hydraulic pressure to the clutch to take up dead stroke and to start the engine, when an instruction to switch to vehicle driving powered by the engine is made in a course of vehicle driving powered by the motor;

speed difference determining means for determining a speed difference between speeds of the motor and the engine;

increase control conducting means for conducting an increase control to increase the output torque of the motor and to increase supply of hydraulic pressure to the clutch based on the determined speed difference, when the engine is started; and

synchronous control conducting means for conducting a synchronous control to reduce the output torque of the engine for a predetermined period of time such that the engine speed is synchronized with the motor speed when the speed difference becomes less than a predetermined threshold value.

2. A system according to claim 1, wherein the synchronous control means begins to increase the supply of hydraulic pressure to a line pressure equivalent value, while beginning to decrease the output toque of motor when the speed difference becomes less than the predetermined value.

3. A system according to claim 2, wherein the synchronous control means begins to increase the supply of hydraulic pressure to the line pressure equivalent value, while beginning to decrease the output toque of motor when the speed difference becomes less than a predetermined second threshold value which is set to be less than the predetermined threshold value.

4. A system according to claim 1, wherein the synchronous control means conducts the synchronous control to reduce the output torque of the engine when the speed difference becomes less than a predetermined second threshold value which is set to be less than the predetermined threshold value.

5. A system according to claim 1, wherein the predetermined threshold value is set to relative to a vehicle speed and a throttle opening.

6. A system according to claim 1, wherein the predetermined threshold value is set to relative to a temperature of operating fluid, vehicle speed and a throttle opening.

7. A system according to claim 1, wherein the synchronous control conducting means conducts the synchronous control to reduce the output torque of the engine for the predetermined period of time that is set to be increased with increasing vehicle speed.

8. A system according to claim 7, wherein the synchronous control conducting means conducts the synchronous control to reduce the output torque of the engine for the predetermined period of time that is set to be increased with increasing vehicle speed and to be further increased with increasing throttle opening change.

9. A system for controlling a hybrid vehicle equipped with an internal combustion engine, an electric motor connected to an output shaft of the engine through a hydraulic clutch and an automatic transmission connected to an output shaft of the motor to be inputted with an output torque outputted from at least one of the engine and the motor to transmit the output torque to driven wheels of the vehicle, comprising

initial control conducting means for conducting an initial control to supply priming hydraulic pressure to the clutch to take up dead stroke and to start the engine, when an instruction to switch to vehicle driving powered by the engine is made in a course of vehicle driving powered by the motor;

engine speed determining means for determining a speed of the engine;

increase control conducting means for conducting an increase control to increase the output torque of the motor and to increase supply of hydraulic pressure to the clutch in synchronized with the detected engine speed, when the engine is started; and

synchronous control conducting means for conducting a synchronous control to reduce the output torque of the engine for a predetermined period of time such that the engine speed is synchronized with the motor speed when the detected engine speed reaches a predetermined engine speed.

10. A system according to claim 9, wherein the increase control means conducts the increase control to increase the output torque of the motor and to increase the supply of hydraulic pressure to the clutch at rates determined by comparing the determined engine speed with a plurality of values indicative of the engine speed.

11. A system according to claim 10, wherein the increase control means conducts a decrease control to decrease the output torque of the motor when the detected engine speed reaches a predetermined second engine speed which is higher than the predetermined engine speed.

12. A system according to claim 9, wherein the synchronous control conducting means conducts the synchronous control to reduce the output torque of the engine, while increasing the supply of hydraulic pressure to a line pressure equivalent value.

14. A method according to claim 13, wherein the step (d) begins to increase the supply of hydraulic pressure to a line pressure equivalent value, while beginning to decrease the output toque of motor when the speed difference becomes less than the predetermined value.

15. A method according to claim 14, wherein the step (d) begins to increase the supply of hydraulic pressure to the line pressure equivalent value, while beginning to decrease the output toque of motor when the speed difference becomes less than a predetermined second threshold value which is set to be less than the predetermined threshold value.

16. A method according to claim 13, wherein the step (d) conducts the synchronous control to reduce the output torque of the engine when the speed difference becomes less than a predetermined second threshold value which is set to be less than the predetermined threshold value.

17. A method according to claim 13, wherein the predetermined threshold value is set to relative to a vehicle speed and a throttle opening.

18. A method according to claim 13, wherein the predetermined threshold value is set to relative to a temperature of operating fluid, vehicle speed and a throttle opening.

19. A method according to claim 13, wherein the step (d) conducts the synchronous control to reduce the output torque of the engine for the predetermined period of time that is set to be increased with increasing vehicle speed.

20. A method according to claim 19, wherein the step (d) conducts the synchronous control to reduce the output torque of the engine for the predetermined period of time that is set to be increased with increasing vehicle speed and to be further increased with increasing throttle opening change.

13. A method of controlling a hybrid vehicle equipped with an internal combustion engine, an electric motor connected to an output shaft of the engine through a hydraulic clutch and an automatic transmission connected to an output shaft of the motor to be inputted with an output torque outputted from at least one of the engine and the motor to transmit the output torque to driven wheels of the vehicle, comprising the steps of:

(a) conducting an initial control to supply priming hydraulic pressure to the clutch to take up dead stroke and to start the engine, when an instruction to switch to vehicle driving powered by the engine is made in a course of vehicle driving powered by the motor;

(b) determining a speed difference between speeds of the motor and the engine;

(c) conducting an increase control to increase the output torque of the motor and to increase supply of hydraulic pressure to the clutch based on the determined speed difference, when the engine is started; and

(d) conducting a synchronous control to reduce the output torque of the engine for a predetermined period of time such that the engine speed is synchronized with the motor speed when the speed difference becomes less than a predetermined threshold value.

21. A method of controlling a hybrid vehicle equipped with an internal combustion engine, an electric motor connected to an output shaft of the engine through a hydraulic clutch and an automatic transmission connected to an output shaft of the motor to be inputted with an output torque outputted from at least one of the engine and the motor to transmit the output torque to driven wheels of the vehicle, comprising the steps of

(a) conducting an initial control to supply priming hydraulic pressure to the clutch to take up dead stroke and to start the engine, when an instruction to switch to vehicle driving powered by the engine is made in a course of vehicle driving powered by the motor;

(b) determining a speed of the engine;

(c) conducting an increase control to increase the output torque of the motor and to increase supply of hydraulic pressure to the clutch in synchronized with the detected engine speed, when the engine is started; and

(d) conducting a synchronous control to reduce the output torque of the engine for a predetermined period of time such that the engine speed is synchronized with the motor speed when the detected engine speed reaches a predetermined engine speed.

22. A method according to claim 21, wherein the step (c) conducts the increase control to increase the output torque of the motor and to increase the supply of hydraulic pressure to the clutch at rates determined by comparing the determined engine speed with a plurality of values indicative of the engine speed.

23. A method according to claim 22, wherein the step (c) conducts a decrease control to decrease the output torque of the motor when the detected engine speed reaches a predetermined second engine speed which is higher than the predetermined engine speed.

24. A method according to claim 21, wherein the step (d) conducts the synchronous control to reduce the output torque of the engine, while increasing the supply of hydraulic pressure to a line pressure equivalent value.