Control system for hybrid vehicle

• US 6,330,498 B2
• Filed: 11/24/1998
• Issued: 12/11/2001
• Est. Priority Date: 11/28/1997
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Yano, Toru, Tamagawa, Yutaka, Oshima, Yoshikazu, Ishikawa, Motoshi
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Assistant Examiner(s): Broadhead, Brian J
• Application Number:
  US09/198,912
• Time in Patent Office: 1,113 Days
• Field of Search: 701/22, 701/54, 701/110, 180/65.2, 180/65.4, 180/65.8
• US Class Current: 701/22
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• 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 10/10 including control of change-speed gearings
• 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 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/0605 Throttle position
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• 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: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/917 : with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/919 : Stepped shift
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio

Abstract

A control system controls a hybrid vehicle having an engine for rotating a drive axle, an electric motor for assisting the engine in rotating the drive axle, and electric energy storage means for supplying electric energy to the electric motor. The control system has an electric motor control unit which calculates an output power of the electric motor depending on an operating status of the hybrid vehicle and assists the engine based on the calculated output power of the electric motor. The electric motor control unit also reduces the output power of the electric motor when the rotational speed of the engine or the speed of the hybrid vehicle exceeds a predetermined value.

Claims

1. A control system for controlling a hybrid vehicle having an engine for rotating a drive axel, an electric motor for assisting the engine in rotating the drive axel, and electric energy storage means for supplying electric energy to the electric motor, comprising:

drive power controlling means for controlling a drive power of the engine;

means for establishing a demand drive power of the hybrid vehicle based on a manipulated variable of the drive power controlling means and a rotational speed of the engine;

drive assistance control means for calculating an assisting output of the electric motor depending on a remaining capacity of the electric energy storage means and the demand drive power, and for calculating an output of the engine based on the calculated assisting output power of the electric motor and the demand drive power;

said drive assistance control means including control means for controlling the electric motor based on the calculated assisting output thereof, and correcting means for correcting the output of the engine based on the calculated output power thereof; and

detecting means for detecting a rotational speed of the engine or a speed of the hybrid vehicle;

said drive assistance control means comprising means for subtracting a predetermined value from the calculated assisting output power of the electric motor when the detected rotational speed of the engine or the detected speed of the hybrid vehicle exceeds a predetermined reference value.

2. A control system according to claim 1, wherein said subtracted predetermined value in the assisting output power of the electric motor is variable depending on the manipulated variable of the drive power controlling means.

3. A control system according to claim 1, wherein, said engine output correcting means increases an output of the engine in synchronism with reducing the assisting output of the electric motor.

4. A control system according to claim 3, wherein said control means for controlling the electric motor controls the electric motor to gradually approach the calculated assisting output power with a predetermined time delay.

5. A control system according to claim 1, wherein said electric energy storage means comprises an electric double-layer capacitor.

6. A control system for controlling a hybrid vehicle having an engine for rotating a drive axle, an electric motor for assisting the engine in rotating the drive axle, electric energy storage means for supplying electric energy to the electric motor, and drive control means for drive power of the engine, comprising:

means for establishing a demand drive power based on a manipulated variable of the drive control means and a rotational speed of the engine;

drive assistance control means for calculating an assisting output of the electric storage means and the demand drive power, and for calculating an output power of the engine based on the calculated assisting output of the motor and the demand drive power;

said drive assistance control means including control means for controlling the electric motor based on the calculated assisting output thereof and a correcting means for correcting the output of the engine based on the calculated output power thereof; and

manipulated variable detecting means for detecting a manipulated variable of the drive power control means;

said drive assistance control means comprising means for subtracting a predetermined value from said calculated assisting output of the electric motor when a manipulated variable of the drive control means is smaller than a predetermined reference value.

7. A control system according to claim 6, wherein said subtracted predetermined value in the assisting output of the electric motor is variable so as to increase as a rotational speed of the engine or a vehicle speed increases.

8. A control system according to claim 6, wherein said predetermined reference value is established so as to increase as a rotational speed of the engine or a speed of the hybrid vehicle increases.

9. A control system according to claim 6, wherein said engine output correcting means increases an output of the engine in synchronism with reducing the assisting output of the electric motor.

10. A control system according to claim 6, wherein said control means for controlling the electric motor controls the electric motor to gradually approach the calculated assisting output with a predetermined time delay.

11. A control system according to claim 6, wherein said electric energy storage means comprises an electric double-layer capacitor.