Controller for hybrid vehicle wherein one and the other of front and rear wheels are respectively driven by engine and electric motor

• US 6,205,379 B1
• Filed: 08/12/1999
• Issued: 03/20/2001
• Est. Priority Date: 09/04/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Mikami, Tsuyoshi, Ichioka, Eiji, Morisawa, Kunio
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US09/374,209
• Time in Patent Office: 586 Days
• Field of Search: 180/165, 180/65.1, 180/65.2, 180/65.3, 180/65.4, 180/65.8, 180/197, 701/22, 701/70, 701/81, 701/89, 318/139, 318/140, 318/141
• US Class Current: 701/22
• CPC Class Codes: B60K 17/356 having fluid or electric motor, for driving one or more wheels disposition of motor in, or adjacent to, traction wheel B60K7/00
• CPC Class Codes: B60K 28/165 acting on elements of the vehicle drive train other than the propulsion unit and brakes, e.g. transmission, clutch, differential acting on brakes B60T8/17
• CPC Class Codes: B60K 5/04 with the engine main axis, e.g. crankshaft axis, transversely to the longitudinal centre line of the vehicle
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/642 Slope of road
• 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: 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 2300/18 Four-wheel drive vehicles
• CPC Class Codes: B60W 2540/106 Rate of change
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/18027 : Drive off, accelerating from standstill
• CPC Class Codes: B60W 40/076 : Slope angle of the road
• 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: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y10S 903/916 : with plurality of drive axles

Abstract

A controller for controlling a hybrid front-and-rear-drive automotive vehicle including a front wheel and a rear wheel an engine, an electric generator operated by the engine, and an electric motor operable with an electric energy generated by the electric generator, and wherein one and the other of the front and rear wheels is driven by the engine and the electric motor, respectively, the controller includes an electric energy storage device, and a cooperative energy supply device for supplying an electric current from the electric energy storage device to the electric motor, concurrently with a supply of an electric energy from the electric generator to the electric motor, to operate the electric motor for driving the other of the front and rear wheels.

Claims

1. A controller for controlling a hybrid front-and-rear-drive automotive vehicle including a front wheel and a rear wheel, an engine, an electric generator operated by said engine, and an electric motor operable with an electric energy generated by said electric generator, and wherein one and the other of said front and rear wheels is driven by said engine and said electric motor, respectively, said controller comprising:

an electric energy storage device; and

cooperative energy supply means for supplying an electric current from said electric energy storage device to said electric motor, concurrently with a supply of an electric energy from said electric generator to said electric motor, to operate said electric motor for driving said other of said front and rear wheels.

2. A controller according to claim 1, wherein said electric energy storage device includes a capacitor which stores the electric energy by polarization of a dielectric material and which has an energy storage capacity sufficient to compensate for an initial shortage of the electric energy to operate said electric motor, which initial shortage would arise from a delayed increase of an amount of the electric energy supplied from said electric generator to said electric motor, if said electric motor were operated with only the electric energy supplied from said electric generator.

3. A controller according to claim 1, further comprising:

a gradient detector for detecting a gradient of a road surface on which the vehicle lies; and

electric power source control means for controlling, depending upon said gradient detected by said gradient detector, a ratio of the amount of electric energy to be supplied from said electric energy storage device to said electric motor, with respect to the amount of electric energy supplied from said electric generator to said electric motor.

4. A controller according to claim 3, wherein said electric power source control means consists of electric power source switching means for zeroing the amount of electric energy to be supplied from said electric energy storage device to said electric motor when said gradient detected by said gradient detector is lower than a predetermined threshold.

5. A controller according to claim 1, further comprising charging means operated immediately after termination of an operation of said electric motor, for charging said electric energy storage device with the electric energy generated by said electric generator, depending upon the amount of electric energy stored in said electric energy storage device immediately after the termination of said operation of said electric motor.

6. A controller according to claim 1, further comprising drive force reducing means for reducing a drive force of said front wheel, if a running speed of the vehicle cannot be raised to a predetermined threshold due to slipping of said front wheel driven by said engine, in spite of an operation of said electric motor.

7. A controller according to claim 6, wherein said drive force reducing means includes engine load increasing means for increasing a load acting on said engine.

8. A controller according to claim 7, wherein the vehicle further includes an automatic transmission through which an output of said engine is transmitted to said one of said front and rear wheels, and said engine load increasing means comprises at least one of:

means for activating an engine-driven device which is operated by said engine and which has been held off;

means for maximizing a load acting on said engine-driven device which has already been activated;

means for shifting up said automatic transmission;

means for effecting partial slipping of a friction coupling device of said automatic transmission which is to be engaged to establish an operating position of said automatic transmission different from a presently established operating position thereof; and

means for increasing the amount of electric energy generated by said electric generator.

9. A controller according to claim 6, wherein the vehicle further includes an automatic transmission through which an output of said engine is transmitted to said one of said front and rear wheels, and said drive force reducing means includes means for effecting partial slipping of a brake of said automatic transmission which has been engaged to hold stationary a reaction member of said automatic transmission to establish a presently selected operating position thereof.

10. A controller according to claim 1, further comprising:

residual energy amount detecting means for determining whether a residual amount of electric energy stored in said electric energy storage device is larger than a predetermined lower limit; and

charging control means operable when said residual energy amount detecting means determines that said residual amount of electric energy is not larger than said predetermined lower limit, for charging said electric energy storage device with an electric energy generated by conversion of a kinetic energy of the vehicle while the vehicle is running in a non-decelerating state.

11. A controller according to claim 10, further comprising vehicle accelerating operation detecting means for determining whether an accelerating operation to accelerate the vehicle has been performed by an operator of the vehicle, and wherein said charging control means is operated to charge said electric energy storage device when said residual energy amount detecting means determines that said residual amount of electric energy stored in said electric energy storage device is not larger than said predetermined lower limit, and when said vehicle accelerating operation detecting means determines that the vehicle accelerating operation has been performed by the operator of the vehicle operator.

12. A controller according to claim 11, wherein the vehicle further includes an automatic transmission disposed between said engine and said one of said front and rear wheels, said controller further comprising transmission speed-ratio increasing means for increasing a speed ratio of said automatic transmission when said vehicle accelerating operation detecting means determines that said accelerating operation has been performed by the operator of the vehicle operator, said speed ration being a ratio of an input speed of said automatic transmission to an output speed of said automatic transmission.

13. A controller according to claim 10, wherein the vehicle further includes an automatic continuously variable transmission disposed between said engine and said one of said front and rear wheels, said controller further comprising:

continuously variable transmission control means for continuously controlling a speed ratio of said continuously variable transmission so that an actual speed of said engine coincides with a target value which is determined on the basis of an actual running speed of the vehicle and a currently required output of said engine, and according to a stored predetermined target determining relationship among said target value, said actual running speed of the vehicle and said currently required output of the engine; and

relationship changing means operable when said vehicle accelerating operation detecting means determines that said accelerating operation to accelerate the vehicle has been performed by the operator of the vehicle, for changing said stored predetermined target determining relationship to a maximum fuel economy relationship, so that said engine is operated with maximum fuel economy with said speed ratio being continuously controlled so that said actual speed of the engine coincides with said target value determined according to said maximum fuel economy relationship.

14. A controller according to claim 10, wherein the vehicle further includes an engine-driven device driven by said engine, said controller further comprising load reducing means for reducing a load acting on said engine-driven device when said residual energy amount detecting means determines that the residual amount of electric energy stored in said electric energy storage device is not larger than said predetermined lower limit, said charging control means being operated when the load acting on said engine-driven device is reduced by said load reducing means.

15. A controller according to claim 14, wherein said charging control means charges said electric energy storage device such that an amount of electric energy stored in said electric energy storage device corresponds to an amount of reduction of the load of said engine-driven device by said load reducing means.