System for driving hybrid vehicle, method thereof and electric power supply system therefor

• US 6,766,874 B2
• Filed: 09/29/1999
• Issued: 07/27/2004
• Est. Priority Date: 09/29/1998
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Katada, Hiroshi, Naito, Shotaro
• Primary Examiner(s): Fischmann, Bryan
• Assistant Examiner(s): Restifo, Jeffrey J.
• Application Number:
  US09/407,989
• Publication Number:
  US 20020007975A1
• Time in Patent Office: 1,763 Days
• Field of Search: 180/65.2, 180/65.3, 180/65.1, 180/65.4, 180/65.8, 701/22, 318/139, 318/140, 323/266, 323/273, 323/275
• US Class Current: 180/65.26
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/54 Transmission for changing ratio
• 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 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60W 10/04 including control of propulsion units
• 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 10/18 including control of braking systems
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2540/06 : Ignition switch
• CPC Class Codes: B60W 2540/10 : Accelerator 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 41/20 : Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02N 11/04 : the motors being associated with current generators
• CPC Class Codes: F02N 11/0822 : related to action of the driver
• CPC Class Codes: F02N 11/0833 : Vehicle conditions F02N11/0822, F02N11/0825 take precedence
• CPC Class Codes: F02N 2200/023 : Engine temperature
• CPC Class Codes: F02N 2200/0801 : Vehicle speed
• CPC Class Codes: F02N 2200/101 : Accelerator pedal position
• CPC Class Codes: F02N 2200/124 : Information about road conditions, e.g. road inclination or surface
• CPC Class Codes: Y02T 10/40 : Engine management systems
• 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 903/917 : with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

A system for driving a hybrid vehicle comprising an engine; a motor/generator coupled to the engine; a battery connected to the motor/generator through an electric power converter; and a controller for controlling the engine and the motor/generator corresponding to driving condition of the vehicle, wherein the controller has a plurality of operating modes for controlling the engine and the motor/generator corresponding to an accelerator opening degree for operating the engine and a charge ratio of the battery, and the controller selects an engine running electric generating mode that the engine is operated as a driving source of the vehicle and the motor/generator and electric power generated by the motor/generator is recovered to the battery when the charge ratio is low; an acceleration mode that the engine and the motor/generator are operated as the driving source of the vehicle when the charge ratio of the battery is high, and the accelerator opening degree or a rate of change of the accelerator opening degree is large; and an engine running mode that only the engine is operated as the driving source of the vehicle when the charge ratio of the battery is high and the accelerator opening degree is small. It is possible to provide a system for driving a hybrid vehicle and a method of driving the hybrid vehicle which can store sufficient electric power in a battery and is excellent in the operating characteristic.

Claims

1. A system for driving a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

a main battery connected to said motor/generator through an electric power converter;

an auxiliary battery connected to said main battery; and

a controller for controlling said engine and said motor/generator;

wherein;

battery voltage of said main battery is higher than battery voltage of said auxiliary battery;

said main battery is used as a power supply for an electromagnetic coil for driving an injector for said engine or intake and exhaust valves, whereby said electromagnetic coil is supplied with said battery voltage of said main battery which is higher than the battery voltage of said auxiliary battery;

said driving motor is operable as a motor to generate driving force for propelling said hybrid vehicle, and is operable as a generator to generate electric power when driven by said hybrid vehicle, said electric power being supplied to said main battery via a converter;

said controller has a plurality of operating modes for controlling said engine and said motor/generator, corresponding to a vehicle operating state and a charge ratio of said main battery; and

said controller selects an engine running electric generating mode in which said engine is operated as a driving source for said vehicle and for said motor/generator, and electric power generated by said motor/generator is recovered to said main battery, when the charge ratio of said main battery is lower than a first predetermined value;

an acceleration mode, in which said engine and said motor/generator are operated as the driving source of the vehicle, when the charge ratio of said main battery exceeds said first predetermined value, and an opening degree of an accelerator for operating said engine exceeds a second predetermined value; and

an engine running mode in which only said engine is operated as the driving source of the vehicle, when the charge ratio of said main battery exceeds said first predetermined value, and said accelerator opening degree is smaller than said second predetermined value.

2. A system for driving a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

a main battery connected to said motor/generator through an electric power converter;

an auxiliary battery connected to said main battery; and

a controller for controlling said engine and said motor/generator;

wherein;

said main battery is controlled to a higher voltage than a voltage of said auxiliary battery, and is used as a power supply for an electromagnetic coil for driving an injector for said engine or intake and exhaust valves;

said controller has a plurality of operating modes for controlling said engine and said motor/generator, corresponding to a vehicle operating state and a charge ratio of said main battery;

said controller selects an engine running electric generating mode in which said engine is operated as a driving source for said vehicle and for said motor/generator, and electric power generated by said motor/generator is recovered to said main battery, when the charge ratio of said main battery is lower than a first predetermined value;

an acceleration mode, in which said engine and said motor/generator are operated as the driving source of the vehicle, when the charge ratio of said main battery exceeds said first predetermined value, and an opening degree of an accelerator for operating said engine exceeds a second predetermined value; and

an engine running mode in which only said engine is operated as the driving source of the vehicle, when the charge ratio of said main battery exceeds said first predetermined value, and said accelerator opening degree is smaller than said second predetermined value; and

said controller selects an engine stopping mode for stopping said engine when a key-switch is in ON state, said accelerator opening degree is in OFF state, a speed of the vehicle is less than a third predetermined value and the charge ratio of said main battery is more than said first predetermined value.

3. A system for driving a hybrid vehicle according to claim 2, wherein said controller also selects said engine stopping mode when a cooling water temperature of said engine is more than a fourth predetermined value and an inclination angle of the vehicle in a stopped state is less than a fifth predetermined value.

4. A system for driving a hybrid vehicle according to claim 2, wherein said controller gives an operating instruction to said motor/generator for a predetermined rotational speed, with said motor/generator being applied as an engine cranking motor, when said engine is started.

5. A system for driving a hybrid vehicle according to claim 3, wherein said controller gives an operating instruction to said motor/generator for a predetermined rotational speed, with said motor/generator being applied as an engine cranking motor, when said engine is started.

6. A system for driving a hybrid vehicle according to claim 3, wherein:

said controller continues an idling operation of said engine when said accelerator is in OFF state and said engine stopping mode is not yet implemented;

thereafter, the controller stops said engine when said engine stopping mode is accomplished.

7. The system for driving a hybrid vehicle according to claim 3, wherein said controller gives an instruction for torque corresponding to one of the accelerator opening degree and a rate of change of the accelerator opening degree, to said motor/generator during an acceleration mode.

8. The system for driving a hybrid vehicle according to claim 3, wherein said controller selects a recovering mode, in which said motor/generator is used as a generator and said main battery is charged, when said key-switch is in said ON state, said accelerator opening degree is in said OFF state, vehicle speed is higher than 0 and the charge ratio of said main battery is less than said first predetermined value.

9. A system for driving a hybrid vehicle according to claim 2, wherein:

said controller continues an idling operation of said engine when said accelerator is in OFF state and said engine stopping mode is not yet implemented;

thereafter, the controller stops said engine when said engine stopping mode is accomplished.

10. The system for driving a hybrid vehicle according to claim 2, wherein said controller gives an instruction for torque corresponding to one of the accelerator opening degree and a rate of change of the accelerator opening degree, to said motor/generator during an acceleration mode.

11. The system for driving a hybrid vehicle according to claim 2, wherein said controller selects a recovering mode, in which said motor/generator is used as a generator and said battery is charged, when said key-switch is in said ON state, said accelerator opening degree is in said OFF state, vehicle speed is higher than 0 and the charge ratio of said main battery is less than said first predetermined value.

12. The system for driving a hybrid vehicle according to claim 11, wherein said controller increases a torque instruction against said motor/generator and increases a braking force, when a brake switch of said vehicle is in an ON state.

13. A system for driving a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

a main battery connected to said motor/generator through an electric power converter;

an auxiliary battery connected to said main battery; and

a controller for controlling said engine and said motor/generator in response to an operating state of the vehicle and a charge ratio of said main battery, wherein;

battery voltage of said main battery is higher than battery voltage of said auxiliary battery;

said main battery is used as a power supply for an electromagnetic coil for driving an injector of said engine or intake and exhaust valves, whereby said electromagnetic coil is supplied with said battery voltage of said main battery which is higher than the battery voltage of said auxiliary battery;

said driving motor is operable as a motor to generate driving force for propelling said hybrid vehicle, and is operable as a generator to generate electric power when driven by said hybrid vehicle, said electric power being supplied to said main battery via a converter;

an engine running electric generating mode is implemented when a charge ratio of said main battery is lower than a first predetermined value, said engine being operated as a driving source for the vehicle and said motor/generator, and electric power generated by said motor/generator being recovered to said main battery;

an acceleration mode is implemented when the charge ratio of said main battery exceeds said first predetermined value and an opening degree of an accelerator for operating said engine or a rate of change of the opening degree of said accelerator exceeds a second predetermined value, said engine and said motor/generator being operated as a driving source of the vehicle; and

an engine running mode is implemented when the charge ratio of said main battery exceeds said first predetermined value and the opening degree of the accelerator is lower than said second predetermined value, only said engine being operated as a driving source of the vehicle.

14. The method for driving a hybrid vehicle according to claim 13, wherein an engine stopping mode is implemented to stop said engine when a vehicle key-switch is in an ON state, the accelerator opening degree is in an OFF state, vehicle speed is less than a third predetermined value, the charge ratio of said main battery exceeds said first predetermined value, a cooling water temperature of the engine exceeds a fourth predetermined value and an inclination angle of the vehicle kept at its stopped state is less than a fifth predetermined value.

15. A system for driving a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

a main battery connected to said motor/generator through an electric power converter;

an auxiliary battery connected to said main battery;

auxiliary equipment operated by electrical power supplied from said auxiliary battery; and

a controller for controlling said engine and said motor/generator;

wherein;

said controller has a plurality of operation modes for controlling said engine and said motor/generator in response to an operating state of the vehicle and a charge ratio of said main battery;

said operating modes including,

an engine running electric generating mode in which said engine is operated as a driving source for the vehicle and said motor/generator, and electrical power generated by said motor/generator is recovered into said main battery, when the charge ratio of said main battery is lower than an upper predetermined charge ratio value V_BMH, and an opening degree of an accelerator for operating said engine is lower than a predetermined value τ

_A, and when a charge ratio of said main battery is lower than a lower predetermined charge ratio value V_BML and the opening degree of said accelerator is larger than τ

_A;

an acceleration mode in which said engine and said motor/generator are operated as a driving source for the vehicle when the charge ratio of said main battery is higher than V_BML and the opening degree of said accelerator is larger than τ

_A;

an engine running mode in which only said engine is operated as a driving source for the vehicle when the charge ratio of said main battery is higher than V_BML and the opening degree of said accelerator is smaller than τ

_A;

an engine stopping mode in which said engine is stopped when a key-switch is in ON state, said accelerator is in an OFF state, vehicle speed is equal to or less than a predetermined speed value, the charge ratio of said main battery is equal to or exceeds V_BML, a cooling water temperature of said engine is equal to or exceeds a predetermined temperature value, or an inclination angle of the vehicle in its stopped state is less than or equal to a predetermined inclination value; and

a starting mode in which said engine is started with said motor/generator when said accelerator is in ON state while said key-switch is in ON state after said engine is stopped.

16. The system for driving a hybrid vehicle according to claim 15, wherein said controller continues an idling operation of said engine when said accelerator is in OFF state and said engine stopping mode is not attained, and thereafter said engine is stopped when said engine stopping mode is attained.

17. The system for driving a hybrid vehicle according to claim 15, wherein said controller gives to said motor/generator a torque instruction corresponding to an opening degree of said accelerator during said acceleration mode.

18. The system for driving a hybrid vehicle according to claim 15, wherein said controller provides a recovery mode in which said motor/generator is operated as a power generator when said key-switch is in ON state, said accelerator is in OFF state, vehicle speed is faster than 0 and the charge ratio of said main battery has not reached a predetermined value.

19. The system for driving a hybrid vehicle according to claim 18, wherein said controller increases a torque instruction to said motor/generator so as to increase a braking force when said brake switch is in ON state.

20. A method for driving a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

a main battery connected to said motor/generator through an electric power converter;

an auxiliary battery connected to said main battery;

auxiliary equipment operated by electrical power supplied from said auxiliary battery; and

a controller for controlling said engine and said motor/generator in response to an operating state of the vehicle and the charge ratio of said main battery, wherein;

in an engine running electric generating mode, said engine is operated as a driving source for said motor/generator and an electrical power generated by said motor/generator is recovered into said main battery when a charge ratio of said main battery is lower than an upper predetermined charge ratio value V_BMH and an opening degree of an accelerator for operating said engine is lower than a predetermined value τ

_A, and when a charge ratio of said main battery is lower than a lower predetermined charge ratio value V_BML and the opening degree of said accelerator is larger than τ

_A;

in an acceleration mode, said engine and said motor/generator are operated as a driving source for the vehicle when the charge ratio of said main battery is higher than V_BML and the opening degree of said accelerator is larger than τ

_A;

in an engine running mode, only said engine is operated as a driving source for the vehicle when the charge ratio of said main battery is higher than V_BMH and the opening degree of said accelerator is smaller than said predetermined value τ

_A;

in an engine stopping mode, said engine is stopped when a key-switch is in ON state, said accelerator is in an OFF state, vehicle speed is equal to or less than a predetermined speed value, the charge ratio of said main battery is equal to or more than V_BML, a cooling water temperature of said engine is equal to or more than a predetermined temperature value or an inclination angle of the vehicle in a stopped state is equal to or less than a predetermined inclination value; and

in a starting mode, said engine is started with said motor/generator when said accelerator is in ON state while said key-switch is in ON state after said engine is stopped.