SYSTEM FOR DRIVING HYBRID VEHICLE, METHOD THEREOF AND ELECTRIC POWER SUPPLY SYSTEM THEREFOR

• US 20020007975A1
• Filed: 09/29/1999
• Published: 01/24/2002
• Est. Priority Date: 09/29/1998
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: NAITO, SHOTARO, KATADA, HIROSHI
• Granted Patent: US 6,766,874 B2
• Time in Patent Office: Days
• US Class Current: 180/65.3
• 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 battery connected to said motor/generator through an electric power converter; and

a controller for controlling said engine and said motor/generator corresponding to driving condition of the vehicle, wherein

said controller has a plurality of operating modes for controlling said engine and said motor/generator corresponding to an accelerator opening degree for operating said engine and a charge ratio of said battery, and said controller selects an engine running electric generating mode that said engine is operated as a driving source of said vehicle and said motor/generator and electric power generated by said motor/generator is recovered to said battery when the charge ratio is low;

an acceleration mode that said engine and said motor/generator are operated as the driving source of the vehicle when the charge ratio of said battery is high and any one of said accelerator opening degree and a rate of change of said accelerator opening degree is large; and

an engine running mode that only said engine is operated as the driving source of the vehicle when the charge ratio of said battery is high and said accelerator opening degree is small.

2. A system for driving a hybrid vehicle according to claim 1, wherein said controller stops said engine to operate as an engine stop mode when a key-switch is in ON state, an accelerator is in OFF state and a speed of the vehicle is slower than a preset value, and the charge ratio is higher than a preset value.

3. A system for driving a hybrid vehicle according to claim 2, wherein said controller selects said engine stop mode when in addition to said stop condition, an engine cooling water temperature is higher than a preset value TS and an inclining angle of the vehicle in a stopping state is smaller than a preset value θ

.

4. A system for driving a hybrid vehicle according to any one of claim 2 and claim 3, wherein said controller controls said engine to continue idling operation when said accelerator is off and said engine stop mode is not satisfied, and then controls said engine to stop operation when said engine stop mode is satisfied.

5. A system for driving a hybrid vehicle according to any one of claim 2 and claim 3, wherein at starting up said engine, said motor/generator receives a command of operating at a preset rotating speed as an engine cranking motor.

6. A system for driving a hybrid vehicle according to any one of claim 2 and claim 3, wherein at said acceleration mode said motor/generator receives a torque command corresponding to any one of said accelerator opening degree and said rate of change of said accelerator opening degree.

7. A system for driving a hybrid vehicle according to any one of claim 2 and claim 3, wherein said motor/generator is used as a generator to charge said battery as a recovery mode when said key-switch is in ON state, said accelerator is in OFF state, the speed of the vehicle is higher than zero and the charge ratio of said battery does not reach a preset value.

8. A system for driving a hybrid vehicle according to claim 7, wherein when a brake switch is on, a brake force is increased by increasing a torque command to said motor/generator.

9. A system for driving a hybrid vehicle according to claim 1, wherein said main battery is used for an electric power source of electromagnetic coils for driving an injector and an intake and an exhaust valves of said engine.

10. A method of driving a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

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

a controller for controlling said engine and said motor/generator corresponding to driving condition of the vehicle, wherein

an engine running electric generating mode is selected when the charge ratio is low, said engine running electric generating mode being that said engine is operated as a driving source of said vehicle and said motor/generator and electric power generated by said motor/generator is recovered to said battery;

an acceleration mode is selected when the charge ratio of said battery is high and any one of said accelerator opening degree and a rate of change of said accelerator opening degree is large, said acceleration mode being that said engine and said motor/generator are operated as the driving source of the vehicle; and

an engine running mode is selected when the charge ratio of said battery is high and said accelerator opening degree is small, said engine running mode being that only said engine is operated as the driving source of the vehicle.

11. A method of driving a hybrid vehicle according to claim 10, wherein operation of said engine is stopped as an engine stop mode when a key-switch is in ON state, an accelerator is in OFF state, the charge ratio is higher than a preset value, an engine cooling water temperature is higher than a preset value TS and an inclining angle of the vehicle in a stopping state is smaller than a preset value θ

.

12. An electric power supply system for a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

a battery connected to said motor/generator through an electric power converter, said battery being composed of a main battery and an auxiliary battery, wherein

said auxiliary battery is connected to said main battery through a switching element and controlled to a voltage lower than a voltage of said main battery, a ground line being commonly used by said main battery and said auxiliary battery, said auxiliary battery being charged from said main battery through said switching element depending on a charge ratio of said main battery when said main battery stores enough electric power.

13. An electric power supply system for a hybrid vehicle according to claim 12, wherein voltage of said main battery is not higher than 60 V, and voltage of said auxiliary battery is 12 V or 24 V.

14. An electric power supply system for a hybrid vehicle according to any one of claim 12 and claim 13, which comprises an auxiliary battery controller for controlling said auxiliary battery, said auxiliary battery controller having a duty calculation part and a PWM control part, said duty calculation part calculating a duty α

corresponding to charge ratios of said main battery and said auxiliary battery, said PWM control part generating a PWM signal corresponding to said duty α

to perform chopper control of said switching element.

15. An electric power supply system for a hybrid vehicle according to any one of claim 12 and claim 13, wherein said main battery is used for an electric power source of electromagnetic coils for driving an injector and an intake and an exhaust valves of said engine.

16. An electric power supply system for a hybrid vehicle comprising an engine;

a motor/generator coupled to said engine;

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

a controller for controlling said engine and said motor/generator corresponding to an operating state of said vehicle, wherein

said controller operates said engine as the drive source of the vehicle and said motor/generator and electric power generated by said motor/generator is recovered to said main battery when charge ratios of said main battery and said auxiliary battery are low, and said auxiliary battery is charged from said main battery through a switching element when a charge ratio of said main battery is high.