Hybrid vehicle and method of controlling hybrid vehicle

• US 6,784,563 B2
• Filed: 11/25/2002
• Issued: 08/31/2004
• Est. Priority Date: 05/24/2000
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nada, Mitsuhiro
• Primary Examiner(s): Ponomarenko, Nicholas
• Assistant Examiner(s): R., Julio Gonzalez
• Application Number:
  US10/302,958
• Publication Number:
  US 20030102673A1
• Time in Patent Office: 645 Days
• Field of Search: 290/40.C, 290/40.A, 180/65.2, 180/65.3, 180/65.4, 180/65.5
• US Class Current: 290/40.00C
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2006/262 the motor or generator are used as clutch, e.g. between engine and driveshaft
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 3/003 relating to inverters
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• 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 10/26 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 2050/021 Means for detecting failure or malfunction
• CPC Class Codes: B60W 2510/06 Combustion engines, Gas turbines
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2710/0616 : Position of fuel or air injector
• CPC Class Codes: B60W 2710/0644 : Engine speed
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: F02D 2041/1422 : Variable gain or coefficients
• CPC Class Codes: F02D 2200/503 : Battery correction, i.e. corrections as a function of the state of the battery, its output or its type
• CPC Class Codes: F02D 2200/602 : Pedal position
• CPC Class Codes: F02D 2250/24 : by using an external load, e.g. a generator
• CPC Class Codes: F02D 31/002 : controlling air supply
• CPC Class Codes: F02D 31/007 : controlling fuel supply
• CPC Class Codes: F02D 41/221 : relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02N 11/04 : the motors being associated with current generators
• CPC Class Codes: F02N 11/0859 : specially adapted to the type of the starter motor or integrated into it
• CPC Class Codes: F02N 11/0866 : comprising several power sources, e.g. battery and capacitor or two batteries
• 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 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor

Abstract

In a hybrid vehicle of the present invention, an engine EG is subjected to feedback control to attain a target revolving speed NE*. In the case of malfunction of an inverter P1 for a generator GN, operation of the inverter P1 is stopped. When the generator GN is driven to rotate at a predetermined rotational speed, a counter electromotive force arises in a multiphase phase coil of the generator GN. When a motor MG is connected to the generator GN as a loading, electric current runs via a protection diode of the inverter P1 to implement power generation by the generator GN. The electric power generated by the generator GN is directly consumed by the motor MG. This arrangement enables the quantity of power generation to balance the quantity of consumption. Here the revolving speed of the engine EG is varied according to the loading applied to the vehicle. The arrangement of the present invention thus enables the amount of electric power generated by one of the generator GN and the motor MG to balance the amount of electric power consumed by the other of the generator GN and the motor MG, thus attaining a drive of the hybrid vehicle without using a secondary battery.

Claims

1. A hybrid vehicle with an engine, a generator, and a motor mounted thereon, said engine outputting power through combustion of a fuel, said generator generating electric power with at least part of the power output from said engine, said motor outputting power to a drive shaft of said hybrid vehicle, said hybrid vehicle comprising:

an engine control unit that feedback controls a quantity of the fuel injected to said engine to attain a specified target revolving speed of said engine;

a generative energy computation unit that computes an instantaneous magnitude of generative energy to be generated by said generator by taking into account an energy balance in a system including said engine, said generator, and said motor;

a voltage measurement unit that measures a generative voltage of said generator;

a control variable computation unit that computes a feedback control variable corresponding to a difference between the observed generative voltage and a target generative voltage of said generator;

a generator control unit that feedback controls said generator with the calculated instantaneous magnitude of generative energy and the calculated feedback control variable;

a requirement detection unit that detects a requirement on a drive of said vehicle; and

a motor driving unit that calculates an output torque of said motor based on a direct torque output from said generator, which is under control of said generator control unit, and a required torque related to the detected requirement on the drive of said vehicle, and drives said motor to attain the calculated output torque.

2. A hybrid vehicle in accordance with claim 1, said hybrid vehicle further comprising:

an inverter that switches electric current running through a multiphase coil of said generator;

a secondary battery that is charged with the direct current converted by the switching operation of said inverter; and

a state-of-failure detection unit that detects a state of failure in feedback control of said generator using the feedback control variable,

wherein said generator uses permanent magnets to form a magnetic field, and said generator control unit comprises a mechanism that stops the switching operation of said inverter and causes said generator to carry out power generation utilizing a counter electromotive force, in response to detection of the state of failure in feedback control of said generator.

3. A hybrid vehicle in accordance with claim 1, said hybrid vehicle further comprising:

a motoring unit that, in a specific driving state where said motor generates electric power, stops the fuel injection to said engine and causes said generator to motor said engine and thereby consume the electric power generated by said motor.

6. A hybrid vehicle in accordance with claim 1, wherein said generator has a pair-rotor structure including a pair of mutually rotatable rotors and carries out power generation to attain a voltage and electric power corresponding to a sliding rotational speed of the two rotors.

7. A hybrid vehicle in accordance with claim 1, wherein said generator is linked with one shaft of a three-shaft power distributor, in which power input to and output from one shaft is determined when powers input to and output from residual two shafts are specified, and

another shaft of said three-shaft power distributor is linked with an output shaft of said engine and still another shaft of said three-shaft power distributor is linked with the drive shaft of said vehicle.

8. A hybrid vehicle in accordance with claim 1, wherein said generator is connected to a first electric power driving circuit that causes said generator to carry out either one of a generative operation and a power operation based on an on-off state of switching elements included in said first electric power driving circuit,

said motor is connected to a second electric power driving circuit that causes said motor to carry out either one of a power operation and a generative operation based on an on-off state of switching elements included in said second electric power driving circuit, and

said first electric power driving circuit is connected to said second electric power driving circuit.

9. A hybrid vehicle in accordance with claim 8, said hybrid vehicle further comprising:

a cutoff unit that cuts off connection between said secondary battery and said first electric power driving circuit; and

a cutoff control unit that actuates said cutoff unit to cut off the connection between said secondary battery and said first electric power driving circuit, when a generative voltage by said generator is higher than an inter-terminal voltage between terminals of said secondary battery.

4. A hybrid vehicle with an engine, a generator, and a motor mounted thereon, said engine outputting power through combustion of a fuel, said generator generating electric power with at least part of the power output from said engine, said motor outputting power to a drive shaft of said hybrid vehicle, said hybrid vehicle comprising:

an engine control unit that feedback controls a quantity of the fuel injected to said engine to attain a specified target revolving speed of said engine;

a secondary battery that is connectable with both positive and negative power lines of a direct voltage source, which link said generator with said motor;

a first contact that switches on and off connection of said secondary battery with one of the two power lines and links said secondary battery with the power line via a restriction resistor, which restricts electric current flowing out of said secondary battery;

a second contact that is connected to the first contact in parallel and directly links said secondary battery with the power line;

a third contact that switches on and off connection of said secondary battery with the other of the two power lines;

a weld detection unit that detects a weld of the third contact; and

a welding-state driving unit that opens both the first contact and the second contact after activation of said engine in response to detection of the weld of the third contact, and drives said motor with the electric power generated by said generator.

5. A hybrid vehicle in accordance with claim 4, said hybrid vehicle further comprising:

a voltage measurement unit that measures both an inter-terminal voltage between terminals of said secondary battery and an inter-power line voltage between the two power lines;

a decision unit that compares the observed inter-terminal voltage with the observed inter-power line voltage while said welding-state driving unit drives said motor; and

a welding-state drive stop unit that stops a drive of said vehicle when said decision unit determines that the observed inter-terminal voltage is equal to the observed inter-power line voltage.

12. A hybrid vehicle in accordance with claim 4, wherein said generator has a pair-rotor structure including a pair of mutually rotatable rotors and carries out power generation to attain a voltage and electric power corresponding to a sliding rotational speed of the two rotors.

13. A hybrid vehicle in accordance with claim 4, wherein said generator is linked with one shaft of a three-shaft power distributor, in which power input to and output from one shaft is determined when powers input to and output from residual two shafts are specified, and

another shaft of said three-shaft power distributor is linked with an output shaft of said engine and still another shaft of said three-shaft power distributor is linked with the drive shaft of said vehicle.

14. A hybrid vehicle in accordance with claim 4, wherein said generator is connected to a first electric power driving circuit that causes said generator to carry out either one of a generative operation and a power operation based on an on-off state of switching elements included in said first electric power driving circuit,

said motor is connected to a second electric power driving circuit that causes said motor to carry out either one of a power operation and a generative operation based on an on-off state of switching elements included in said second electric power driving circuit, and

said first electric power driving circuit is connected to said second electric power driving circuit.

10. A method of controlling a hybrid vehicle, wherein an engine outputs power through combustion of a fuel, a generator provided with permanent magnets generate electric power with at least part of the power output from said engine, and a motor is driven with at least part of the electric power generated by said generator, so as to output power to a drive shaft of said vehicle, said method comprising the steps of:

feedback controlling a quantity of the fuel injected to said engine to attain a specified target revolving speed of said engine;

computing an instantaneous magnitude of generative energy to be generated by said generator by taking into account an energy balance in a system including said engine, said generator, and said motor;

measuring a generative voltage of said generator;

computing a feedback control variable corresponding to a difference between the observed generative voltage and a target generative voltage of said generator;

feedback controlling said generator with the calculated instantaneous magnitude of generative energy and the calculated feedback control variable;

detecting a requirement on a drive of said vehicle; and

calculating an output torque of said motor based on a direct torque output from said generator, which is under control of said generator control unit, and a required torque related to the detected requirement on the drive of said vehicle, and driving said motor to attain the calculated output torque.

11. A method of controlling a hybrid vehicle, wherein an engine outputs power through combustion of a fuel, a generator provided with permanent magnets generate electric power with at least part of the power output from said engine, and a motor is driven with at least part of the electric power generated by said generator, so as to output power to a drive shaft of said vehicle, said method comprising the steps of:

connecting a secondary battery with both positive and negative power lines of a direct voltage source, which link said generator with said motor;

interposing a first contact between said secondary battery and one of the two power lines via a restriction resistor, which restricts electric current flowing out of said secondary battery;

connecting a second contact to the first contact in parallel, the second contact directly linking said secondary battery with the power line;

interposing a third contact between said secondary battery and the other of the two power lines;

feedback controlling a quantity of the fuel injected to said engine to attain a specified target revolving speed of said engine;

detecting a weld of the third contact; and

opening both the first contact and the second contact after activation of said engine in response to detection of the weld of the third contact, and driving said motor with the electric power generated by said generator.