Hybrid vehicle

• US 20040238244A1
• Filed: 11/06/2003
• Published: 12/02/2004
• Est. Priority Date: 11/12/2002
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Sugiyama, Tetsu, Amanuma, Hirokatsu, Oshida, Shuji
• Granted Patent: US 6,988,779 B2
• Time in Patent Office: Days
• US Class Current: 180/65.2
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/44 Series-parallel type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 2220/42 with use of more than one motor
• CPC Class Codes: B60L 2240/18 lateral
• CPC Class Codes: B60L 2240/24 Steering angle
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/465 Slip
• CPC Class Codes: B60L 2240/642 Slope of road
• CPC Class Codes: B60L 2260/28 Four wheel or all wheel drive
• 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 58/15 Preventing overcharging
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 2270/602 ABS features related thereto
• 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2520/125 : Lateral acceleration
• CPC Class Codes: B60W 2520/14 : Yaw
• CPC Class Codes: B60W 2520/28 : Wheel speed
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2540/18 : Steering angle
• CPC Class Codes: B60W 2552/15 : Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/207 : Steering angle of wheels
• 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

Abstract

In a hybrid vehicle, an engine is connected to front wheels through a first motor/generator and a transmission, and a second motor/generator is connected to rear wheels. The first and second motors/generators are connected to a battery so that they are driven or regenerated. During regenerative braking of the vehicle, the distribution ratio of regenerative braking forces to the first and second motors/generators is controlled to become an ideal distribution ratio corresponding to a longitudinal acceleration (deceleration) of the vehicle, whereby the distribution ratio of the braking forces to the front and rear wheels can be always maintained at an optimal value during rapid deceleration as well as during slow deceleration of the vehicle, to improve the braking performance.

Claims

1. A hybrid vehicle in which an engine is connected to first driven wheels through a first motor/generator and a transmission, and a second motor/generator is connected to second driven wheels, said first and second motors/generators being connected to an accumulating means so that they are driven or regenerated,

wherein distribution ratio of braking forces to the first and second motors/generators is controlled to become an ideal distribution ratio corresponding to a longitudinal acceleration of the vehicle during regenerative braking of the vehicle.

2. A hybrid vehicle according to claim 1, wherein the first and second driven wheels are front and rear wheels, respectively, and when the vehicle is traveling down a slope, the distribution ratio of the regenerative braking force to the second motor/generator is decreased to be smaller than the ideal distribution ratio.

3. A hybrid vehicle according to claim 2, wherein, when the vehicle is traveling down the slope, a degree of inclination of a road surface is calculated based on a vehicle speed and a longitudinal acceleration of the vehicle.

4. A hybrid vehicle according to claim 1, wherein the first and second driven wheels are front and rear wheels, respectively, and when a lateral acceleration of the vehicle exceeds a predetermined value and a vehicle speed exceeds a predetermined value, the distribution ratio of the regenerative braking force to the second motor/generator is decreased to be smaller than said ideal distribution ratio.

5. A hybrid vehicle according to claim 4, wherein the lateral acceleration of the vehicle is calculated based on the vehicle speed and a steering angle.

6. A hybrid vehicle according to claim 4 or 5, wherein the decreasing control of the distribution ratio of the regenerative braking force to the second motor/generator (MG2) is carried out in response to the start of the steering.

7. A hybrid vehicle according to claim 1, wherein the first and second wheels are front and rear wheels, respectively, and when a yaw rate of the vehicle exceeds a predetermined value, the distribution ratio of the regenerative braking force to the second motor/generator is decreased to be smaller than said ideal distribution ratio.

8. A hybrid vehicle according to claim 1, wherein, during operation of a mechanical brake, a braking force for the second driven wheels determined depending on said ideal distribution ratio is generated by the second motor/generator and the mechanical brake, and a deficiency of the regenerative braking force for the second motor/generator limited by the remaining capacity of the accumulating means is made up by a braking force of the mechanical brake.

9. A hybrid vehicle according to claim 8, wherein, when the braking force of the mechanical brake exceeds a predetermined value, a threshold value for the remaining capacity of the accumulating means permitting the regenerative braking of the second motor/generator is increased.

10. A hybrid vehicle according to claim 1, wherein the engine is constructed so that the rotational resistance can be decreased by the stopping of cylinders, and when the engine is brought into a cylinder-stopped state to regeneratively brake the vehicle, if the remaining capacity of the accumulating means exceeds a predetermined value, the cylinder-stopped state of the engine is canceled, and the first motor/generator is driven by an electric power generated by the second motor/generator so that an increment in rotational resistance of the engine due to the cancellation of the cylinder-stopped state is countervailed.

11. A hybrid vehicle according to claim 1, wherein the first and second driven wheels are front and rear wheels, respectively, and the distribution ratio of the regenerative braking force to the second motor/generator is increased in accordance with a decrease in a road surface friction coefficient.

12. A hybrid vehicle according to claim 1, wherein the regenerative braking of the first and second motors/generators is prohibited during an ABS control.