Regenerative braking system for motor vehicles

• US 20060055240A1
• Filed: 09/09/2005
• Published: 03/16/2006
• Est. Priority Date: 09/10/2004
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Sugimoto, Tomonaga, Konishi, Masaru, Isono, Yoichi, Toyota, Hiromitsu
• Granted Patent: US 7,458,650 B2
• Time in Patent Office: Days
• US Class Current: 303/152
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• 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 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 2270/604 Merging friction therewith; Adjusting their repartition
• CPC Class Codes: B60T 2270/608 Electronic brake distribution (EBV/EBD) features related thereto
• 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 10/184 with wheel brakes
• 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 2510/207 Oversteer or understeer
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: F16H 2037/0866 : Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A regenerative braking system has a generator connected to at least one wheel set to apply regenerative brake torque to it by generating electricity, a regenerative braking control means controlling a regenerative braking amount, an actual wheel speed variation calculating means calculating an actual wheel speed variation between actual outer-wheel speed of an outer wheel of steerable wheels and actual inner-wheel speed of at least one wheel of front and rear wheel sets, a correspondent wheel speed variation calculating means calculating a correspondent wheel speed variation corresponding to an outer-to-inner wheel speed variation of the steerable wheels with road grip, a steer characteristic judging means judging strength of a steer characteristic based on the correspondent wheel speed variation and the actual wheel speed variation, and a regenerative braking amount compensating means compensating the amount to be more decreased as the steer characteristic becomes stronger.

Claims

1. A regenerative braking system for motor vehicles comprising:

a generator that is connected with a wheel set, the generator being capable of applying regenerative brake torque to the wheel set by generating electricity;

a regenerative braking control means that controls a regenerative braking amount of the generator based on at least demand brake force amount;

an actual wheel speed variation calculating means that calculates an actual wheel speed variation between actual outer wheel speed of an outer wheel of steerable wheels and actual inner wheel speed of at least one wheel of a front wheel set and a rear wheel set;

a correspondent wheel speed variation calculating means that calculates a correspondent wheel speed variation corresponding to an outer-to-inner wheel speed variation between outer wheel speed and inner wheel speed of the steerable wheels with road grip;

a steer characteristic judging means that judges that a steer characteristic to become stronger as a numerical value of a correspondent-to-actual wheel speed variation between the correspondent wheel speed variation and the actual wheel speed variation becomes larger; and

a regenerative braking amount compensating means that compensates the regenerative braking amount so that the regenerative braking amount is more decreased as the steer characteristic becomes stronger.

2. A regenerative braking system for motor vehicles according to claim 1, wherein

the wheel set connected with the generator is steerable wheel set, and the steer characteristic is under steer.

3. A regenerative braking system for motor vehicles according to claim 2, wherein

the actual wheel speed variation calculating means calculates the actual wheel speed variation based on actual outer wheel speed and the actual inner wheel speed of the steerable wheels.

4. A regenerative braking system for motor vehicles according to claim 2, further comprising:

a steering angle sensor that detects a steering angle, wherein

the correspondent wheel speed variation calculating means calculates the correspondent wheel speed variation based on an estimated vehicle body speed obtained from an average wheel speed of non-steerable wheels and based on a cornering radius corresponding value obtained from a steering angle.

5. A regenerative braking system for motor vehicles according to claim 2, wherein

the regenerative braking amount compensating means compensates the regenerative braking amount so that the regenerative braking amount is more decreased as the understeer becomes stronger and the actual wheel speed variation becomes larger.

6. A regenerative braking system for motor vehicles according to claim 2, further comprising:

a steering angle sensor that detects a steering angle, wherein

the regenerative braking amount compensating means compensates the regenerative braking amount so that the regenerative braking amount is more decreased as the understeer becomes stronger and the steering angle becomes larger.

7. A regenerative braking system for motor vehicles according to claim 2, wherein

the actual wheel speed variation calculating means calculates the actual wheel speed variation between the actual outer wheel speed of the outer wheel of the steerable wheels and the actual inner wheel speed of an inner wheel of non-steerable wheels.

8. A regenerative braking system for motor vehicles according to claim 2, wherein

the front wheel set is the wheel set connected with the generator and the steerable wheels and capable of being driven, and

the regenerative control means controls the generator so that only regenerative braking is applied to the wheel set when the demand brake amount is no more than the regenerative braking amount and that the regenerative braking and mechanical braking are cooperatively applied to the wheel set when the demand brake amount is more than the regenerative braking amount.

9. A regenerative braking system for motor vehicles according to claim 1, wherein

the actual wheel speed variation calculating means calculates the actual wheel speed variation based on actual outer wheel speed and the actual inner wheel speed of the steerable wheels.

10. A regenerative braking system for motor vehicles according to claim 1, further comprising:

a steering angle sensor that detects a steering angle, wherein

the correspondent wheel speed variation calculating means calculates the correspondent wheel speed variation based on an estimated vehicle body speed obtained from an average wheel speed of non-steerable wheels and based on a cornering radius corresponding value obtained from a steering angle.

11. A regenerative braking system for motor vehicles according to claim 1, wherein

the regenerative braking amount compensating means compensates the regenerative braking amount so that the regenerative braking amount is more decreased as the steer characteristic becomes stronger and the actual wheel speed variation becomes larger.

12. A regenerative braking system for motor vehicles according to claim 1, further comprising:

a steering angle sensor that detects a steering angle, wherein

the regenerative braking amount compensating means compensates the regenerative braking amount so that the regenerative braking amount is more decreased as the steer characteristic becomes stronger and the steering angle becomes larger.

13. A regenerative braking system for motor vehicles according to claim 1, wherein

the actual wheel speed variation calculating means calculates the actual wheel speed variation between the actual outer wheel speed of the outer wheel of the steerable wheels and the actual inner wheel speed of an inner wheel of non-steerable wheels.

14. A regenerative braking system for motor vehicles according to claim 1, wherein

the front wheel set is the wheel set connected with the generator and the steerable wheels and capable of being driven, and

the regenerative control means controls the generator so that only regenerative braking is applied to the wheel set when the demand brake amount is no more than the regenerative braking amount and that the regenerative braking and mechanical braking are cooperatively applied to the wheel set when the demand brake amount is more than the regenerative braking amount.