Braking force control apparatus for vehicle and method thereof

• US 6,898,506 B2
• Filed: 03/20/2003
• Issued: 05/24/2005
• Est. Priority Date: 04/09/2002
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Hanada, Hideto, Kawai, Takashi, Tsujii, Hiroshi, Kuretake, Ken, Sugiura, Masanori
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): MANCHO, RONNIE M
• Application Number:
  US10/392,187
• Publication Number:
  US 20030191574A1
• Time in Patent Office: 796 Days
• Field of Search: 701/22, 701/84, 701/54, 701/113, 701/36, 701/79, 701/70, 477/205, 477/187, 477/203, 477/3, 477/7, 180 651- 656, 180/711, 180/852, 607/06, 606/98
• US Class Current: 701/84
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/525 Temperature of converter or components thereof
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2260/24 Coasting mode
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• 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 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 2510/0275 Clutch torque
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: F16H 61/143 using electric control means
• CPC Class Codes: Y02T 10/60 Other road transportation technologies with climate change mitigation effect
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/917 with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

The braking force control apparatus for a vehicle which has a function of applying a braking force to the vehicle by rotational resistance of the engine, by stopping the fuel supply to the engine during coasting of the vehicle and by controlling a torque capacity of a torque capacity control device that is provided between the engine and a wheel so that the torque capacity becomes equal to or higher than a predetermined value, and of decreasing the torque capacity of the torque capacity control device when a predetermined condition is satisfied, and has a function of applying the braking force to the vehicle by a function of an electric power generator which is coupled with the wheel such that power can be transmitted. The braking force control apparatus includes braking force control means which increases a braking force that is generated by the function of the electric power generator when the torque capacity of the torque capacity control device is decreased.

Claims

1. A braking force control apparatus for a vehicle, comprising:

an engine;

a fuel supply control device which controls a fuel supply to the engine during coasting of the vehicle;

a torque capacity control device which is provided between the engine and a wheel, and which controls a torque capacity between the engine and the wheel;

an electric power generator that is coupled with the wheel such that power can be transmitted; and

a braking force control device which applies to the vehicle a braking force through rotational resistance of the engine, by stopping the fuel supply to the engine during coasting of the vehicle and by controlling the torque capacity so that the torque capacity becomes equal to or higher than a predetermined value, and which decreases the torque capacity and increases a braking force generated by the electric power generator when a predetermined condition is satisfied,

wherein, when the torque capacity is decreased, the braking force control device increases the braking force generated by the electric power generator compared with a braking force generated by the electric power generator which is obtained before or when the torque capacity is decreased.

2. The control apparatus according to claim 1 wherein, the braking force control device decreases the braking force generated by the electric power generator with time.

3. The control apparatus according to claim 1, further comprising:

an estimation portion which estimates a total braking force when the torque capacity of the torque capacity control device is decreased, and the braking force generated by the electric power generator is increased; and

a fuel supply portion which determines time for supplying the fuel to the engine based on a result of estimation obtained by the estimation portion.

4. The control apparatus according to claim 3, further comprising:

a comparison portion which compares the total braking force that is estimated by the estimation portion with a total braking force before the torque capacity of the torque capacity control device is decreased, wherein the fuel supply portion starts the fuel supply to the engine based on a result of a comparison between the total braking force that is estimated by the estimation portion and the total braking force before the torque capacity of the torque capacity control device is decreased, before the torque capacity of the torque capacity control device is decreased.

5. The control apparatus according to claim 1, wherein a regenerative braking force is included in the braking force generated by a function of the electric power generator.

6. The control apparatus according to claim 1, wherein the torque capacity control device is a torque converter with a lockup clutch which is engaged or disengaged such that torque transmission between the engine and the wheel is mechanically connected or cut off, and the braking force control device stops the fuel supply to the engine during coasting of the vehicle by the fuel supply control device, engages the lockup clutch so as to apply the braking force to the vehicle by the rotational resistance of the engine, and when the predetermined condition is satisfied, the braking force control device disengages the lockup clutch and increases the braking force generated by the electric power generator.

7. The control apparatus according to claim 1, wherein the braking force control device suppresses a decrease in the total braking force, which is a sum of the braking force by the rotational resistance of the engine and the braking force generated by the electric power generator, by increasing the braking force generated by the electric power generator when the predetermined condition is satisfied.

8. The control apparatus according to claim 1, wherein the predetermined condition includes a case where a vehicle speed becomes equal to or lower than a predetermined value.

9. A braking force control apparatus for a vehicle, comprising:

an engine;

a fuel supply control means for controlling a fuel supply to the engine during coasting of the vehicle;

a torque capacity control means which is provided between the engine and a wheel, and for controlling a torque capacity between the engine and the wheel;

an electric power generator that is coupled with the wheel such that power can be transmitted; and

a braking force control means for applying to the vehicle a braking force through rotational resistance of the engine, by stopping the fuel supply to the engine during coasting of the vehicle and by controlling the torque capacity so that the torque capacity becomes equal to or higher than a predetermined value, and which decreases the torque capacity and increases a braking force generated by the electric power generator when a predetermined condition is satisfied,

wherein, when the torque capacity is decreased, the braking force control device increases the braking force generated by the electric power generator compared with a braking force generated by the electric power generator which is obtained before or when the torque capacity is decreased.

10. The control apparatus according to claim 9 wherein, the braking force control means decreases the braking force generated by the electric power generator with time.

11. The control apparatus according to claim 9, further comprising:

an estimation means for estimating a total braking force when the torque capacity of the torque capacity control means is decreased, and the braking force generated by the electric power generator is increased; and

a fuel supply means for determining time for supplying the fuel to the engine based on a result of estimation obtained by the estimation means.

12. The control apparatus according to claim 11, further comprising:

a comparison means for comparing the total braking force that is estimated by the estimation means with a total braking force before the torque capacity of the torque capacity control means is decreased, wherein the fuel supply means starts the fuel supply to the engine based on a result of a comparison between the total braking force that is estimated by the estimation means and the total braking force before the torque capacity of the torque capacity control means is decreased, before the torque capacity of the torque capacity control means is decreased.

13. A method of controlling a braking force of a vehicle which includes a torque capacity control device that is provided between an engine and a wheel, and an electric power generator that is coupled with the wheel such that power can be transmitted, comprising:

applying to the vehicle a braking force through rotational resistance of the engine, by stopping fuel supply to the engine during coasting of the vehicle and by controlling a torque capacity of the torque capacity control device so that the torque capacity becomes equal to or higher than a predetermined value, and

decreasing the torque capacity of the torque capacity control device and increasing a braking force generated by the electric power generator when a predetermined condition is satisfied,

wherein, when the torque capacity is decreased, the braking force control device increases the braking force generated by the electric power generator compared with a braking force generated by the electric power generator which is obtained before or when the torque capacity is decreased.

14. The control method according to claim 13, wherein the braking force generated by the electric power generator is decreased with time.

15. The control method according to claim 13, further comprising the steps of:

decreasing the torque capacity of the torque capacity control device, and estimating a total braking force when the braking force generated by the electric power generator is increased, and

determining time for supplying the fuel to the engine based on a result of the estimation.

16. The control method according to claim 15, further comprising the step of:

comparing the estimated total braking force with a total braking force before the torque capacity of the torque capacity control device is decreased, wherein the determination portion determines the fuel supply to the engine based on a result of the comparison between the estimated total braking force and the total braking force before the torque capacity of the torque capacity control device is decreased, before the torque capacity of the torque capacity control device is decreased.