Fluid-pressure and analogous brake systems – Speed-controlled – Regenerative brakes
Reexamination Certificate
1997-10-01
2001-12-04
Oberleitner, Robert J. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
Regenerative brakes
C303S186000
Reexamination Certificate
active
06325470
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application is related to co-pending applications, entitled “METHOD AND APPARATUS FOR REGENERATIVE AND FRICTION BRAKING”, “METHOD AND APPARATUS FOR REGENERATIVE AND FRICTION BRAKING” and “METHOD AND APPARATUS FOR REGENERATIVE AND ANTI-SKID FRICTION BRAKING”, respectively, all filed on Sep. 30, 1997 and assigned to the assignee of the present application.
This invention relates generally to a method and apparatus for regenerative and friction braking of a motor vehicle having an electric drive motor. More particularly, the present invention relates to proportioning regenerative braking to maintain a desirable front to rear brake distribution.
2. Disclosure Information
The general principle of regenerative braking has been recognized by manufacturers of electric vehicles as a way of increasing the overall efficiency of the vehicle. Regenerative braking seeks to recover as much of the kinetic energy of the vehicle which is normally dissipated as heat through a normal hydraulic friction system by operating the electric motor drive as a generator and restoring the generated electricity to a battery or other energy storage device. Various methods have been proposed for accomplishing regenerative braking in such electric vehicles, however, these regenerative systems generally require additional hardware above and beyond that normally associated with a hydraulic braking system. Further, it has been observed that some regenerative braking systems do not provide desirable proportioning of the front and rear braking torques.
It would therefore be advantageous to provide a proportional regenerative braking system capable of proportioning the regenerative brake torque to maintain a desirable front to rear brake distribution.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a method and apparatus for providing regenerative and friction braking on a vehicle having one or more wheels driven by a drive motor utilizing hardware from a conventional anti-skid hydraulic friction braking system. The regenerative and friction braking apparatus includes a master cylinder for generating a hydraulic signal in response to a driver brake command and a pressure sensor for generating a pressure signal representative of the hydraulic signal. A throttle sensor is also included for generating an acceleration signal in response to a driver acceleration command.
The apparatus also includes an undriven left wheel having a first brake actuator and a first speed sensor operatively associated therewith for generating an undriven left wheel speed signal as well as an undriven right wheel having a second brake actuator and a second speed sensor operatively associated therewith for generating an undriven right wheel speed signal. Additionally, driven left and right wheels connect to the drive motor and include third and fourth brake actuators and third and fourth speed sensors operatively associated therewith for generating driven left and right wheel speed signals.
A hydraulic control unit is provided and is in fluid communication with hydraulic signal from the master cylinder. The hydraulic control unit also communicates with the first, second, third and fourth brake actuators, respectively.
The apparatus further includes a power storage device in communication with the drive motor. A brake controller is provided for commanding the hydraulic control unit in response to the pressure signal and the driven and undriven left and right wheel speed signals.
A drive motor controller is included for determining a coast down regenerative torque signal and a driver brake command regenerative torque signal and commanding the drive motor to regeneratively brake the driven left and right wheels in response to whichever of the coast down regenerative torque signal and the driver brake command regenerative torque signal is greatest, thereby maintaining a desirable proportioning of front to rear braking.
The method of operating the regenerative and friction braking apparatus for the vehicle comprises the steps of:
generating a hydraulic signal in response to a driver brake command as applied to a master cylinder;
producing a pressure signal representative of the hydraulic signal;
producing an acceleration signal in response to a driver acceleration command;
determining a coast down regenerative torque signal from the accelerator signal;
determining a driver brake command regenerative torque signal in response to said pressure signal; and
commanding the drive motor to regeneratively brake the driven left and right wheels in response to whichever of the coast down regenerative torque signal and the driver brake command regenerative torque signal is greatest, thereby maintaining a desirable proportioning of front to rear braking.
Advantageously, the method and apparatus for providing regenerative and friction braking efficiently recovers the kinetic energy normally lost through heat generation and dissipation resulting from the use of conventional hydraulic brake systems while maintaining a desirable proportioning of front to rear braking torques.
REFERENCES:
patent: 4962969 (1990-10-01), Davis
patent: 5253929 (1993-10-01), Ohori
patent: 5326158 (1994-07-01), Ohori et al.
patent: 5326160 (1994-07-01), Bayliss et al.
patent: 5378053 (1995-01-01), Patient et al.
patent: 5421643 (1995-06-01), Kircher et al.
patent: 5450324 (1995-09-01), Cikanek
patent: 5492192 (1996-02-01), Brooks et al.
patent: 5505527 (1996-04-01), Gray, Jr. et al.
patent: 5511859 (1996-04-01), Kade et al.
patent: 5568962 (1996-10-01), Enomoto et al.
patent: 5573312 (1996-11-01), Müller et al.
patent: 5615933 (1997-04-01), Kidston et al.
patent: 5707115 (1998-01-01), Bodie et al.
Article, “Electronic Brake Force Distribution Control—A Sophisticated Addition to ABS”, Gunther Buschmann, Hans-Thomas Ebner, and Weiland Kuhn.
Kajander John E.
Oberleitner Robert J.
Visteon Global Technologies Inc.
Williams Thomas J.
LandOfFree
Method and apparatus for proportioning regenerative braking does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for proportioning regenerative braking, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for proportioning regenerative braking will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2589055