Kelsey-hayes Company

Mark S Luckevich

Dan Negrin

Bernard W Johnson

Andrew W Kingston

Gregory P Campau

Brian C Tuck

Blaise J Ganzel

Thomas Weigert

Salvatore Oliveri

Robert L Ferger

Danny R Milot

Darryl C Weber

Edward R Hornback

Clark E Lowman

James H DeVore

Mark R Bielek

John D Cotner

An improved electro-hydraulic brake system having features for improving the pedal feel of the system, while further having design features which contribute to the economy of manufacture of certain components of the system. The system provides for an electrically powered normal source of pressurized hydraulic brake fluid, and a manually powered backup source of pressurized hydraulic brake fluid to the vehicle brakes in the event of failure of the normal source. During normal braking, fluid from the backup source is redirected from the vehicle brakes to a pedal simulator. The pedal simulator preferably includes arrangements of spring loaded pistons, expansion volumes, and damping orifices, together with valves selectively controlling the flow of fluid to and from the pedal simulator which provides for an improved pedal feel during vehicle braking. The brake system of the invention further includes a relatively low cost fluid separator unit which is provided which prevents intermixing of pressurized fluid between the backup source and the normal source. The fluid separator unit acts to permit the normal source to act upon the hydraulic brake fluid of the backup source to operate the vehicle brakes. The fluid separator unit is preferably embodied as a piston having two working faces, each of the same diameter.

Electronic brake management system with manual fail safe

A brake control system determines utilizes a sensed amount of brake travel and a sensed amount of master cylinder pressure in determining a base brake control signal for an electro-hydraulic brake management system. The system also provides a springer function to provide an appropriate amount of brake jump-in, based on vehicle velocity and pedal travel. For pure brake-by-wire systems that have no hydraulic components, brake force is substituted for master cylinder pressure in determining a base brake control signal.

Foundation brake control algorithm for electro-hydraulic brake system and brake-by-wire system

An electronic brake management system for controlling the application of fluid pressure to the brakes associated with wheels on a vehicle is disclosed. The system comprises a plurality of hydraulic valves for controlling the application of fluid to the brakes and a plurality of valve drivers for controlling the valves in accordance with respective electrical control signals for the plurality of valves. The system further includes a valve pulse width modulation controller for generating the respective electrical valve control signals applied to the valve drivers. The electrical valve control signals from the pulse width modulation controller are modulated to reduce the amount of electrical power supplied by the individual ones of the electrical signals once the valve associated with the one of the electrical signals has changed its opening to a desired position. The system further includes a brushless motor for driving a hydraulic pump for supplying fluid to the brakes in accordance with a pulse width modulated motor control signal from a motor signal modulation controller. The brushless motor provides a feedback signal to the motor signal modulation controller which is indicative of the position of the brushless motor rotor.

Electronic brake management system with a signal modulation controller and a brushless motor

A brake control system determines when a wheel is unstable or stable during a braking condition. An unstable wheel is determined when the wheel speed is different from the estimated vehicle speed by greater than a fixed amount. When the wheel is determined to be unstable, an amount of brake pressure reduction is determined according to a proportional-plus-integral compensation. The proportional-plus-integral compensation is a function of the difference between the wheel speed and the estimated vehicle speed, as well as a wheel deceleration value. When the wheel is determined to be stable, brake pressure is applied according to an exponential rate. A hold mode is entered when the wheel is determined to be no longer decelerating during a dump cycle.

Brake control using proportional plus integral slip regulation and

A method and system, for use with a vehicle including a pair of front wheels, a pair of rear wheels, and an anti-lock brake system (ABS), for detecting when the vehicle is executing a turning maneuver. The system includes means for performing the method steps of determining a speed difference between one pair of the vehicle wheels, determining the deceleration of each of the one pair of vehicle wheels, comparing the speed difference to a turning detection threshold, comparing the decelerations to a deceleration threshold, and detecting a turning maneuver based on those comparisons.

Method and system for turning detection

A control method and system for a vehicle anti-lock brake system to provide for recovery from premature activation of the vehicle anti-lock brake system. The control system includes a microprocessor and accompanying components to perform the control method steps of generating an input signal representing a vehicle wheel velocity, processing the input signal to determine a wheel slip duration, comparing the wheel slip duration to a slip duration threshold, generating a premature activation recovery control signal when the wheel slip duration fails to exceed the slip duration threshold, and performing premature activation recovery control of the anti-lock brake system in response to the premature activation recovery control signal.

Early activation recovery control method and system for vehicle

A brake pressure controller, responsive to a wheel speed sensor and coupled to a brake, performs a cyclic control of pressure applied to the brake. A brake pressure cycle includes a pressure apply stage and a pressure dump stage having activation conditions based upon a slip threshold parameter. A predetermined base threshold quantity is modified in dependence upon a measured time duration of the pressure dump stage and/or a slip depth error quantity so that a greater amount of slip is added to the base slip threshold when braking on a deformable surface than when braking on a non-deformable surface.

Method and system for antilock braking on a deformable surface

A dynamic rear proportioning system is integrated with an existing vehicle anti-lock braking system (ABS) and performs the function of the rear brake pressure proportioning where ABS is not required. The rear brake hydraulic channel(s) are isolated from the master cylinder by activating the rear isolation valves, provided in the ABS, to provide the optimum brake force balance, regardless of vehicle loading, without the use of a load sensing mechanism. The system estimates vehicle and wheel deceleration, vehicle speed, and lateral acceleration as well as the rear wheel slip to dynamically control the rear brake force. By continually updating these control parameters, the system can further increase or decrease the rear brake pressure to maintain the optimum brake force balance throughout the braking maneuver.

Dynamic rear proportioning brake system

A method and system for controlling an anti-lock brake system cycle rate in a vehicle wherein the cycle includes a primary apply stage and a secondary apply stage in which increasing pressure is applied to the brake. The primary and secondary stages are separated by a hold stage in which a substantially constant pressure is applied to the brake for a time interval which varies as a function of the estimated average vehicle deceleration.

Anti-lock brake method and system including a variable primary to

A method and system for modifying anti-lock brake control to a vehicle braking on a split mu surface. Each of the wheel speeds are sensed and compared to a wheel speed reference. If the speed of only one of the front wheels departs from the wheel speed reference in excess of a predetermined slip threshold, a split mu control is activated. Upon detecting a departure of the high mu wheel, a first pressure control profile is applied to the low mu wheel, while a second control pressure profile different from the first pressure control profile is applied to the high mu wheel. Once the vehicle has transitioned from braking on a split mu surface to braking on a homogeneous mu surface, normal ABS control pressure is applied to the wheels.

Method and system for split mu control for anti-lock brake systems

A reduced brake switch dependence (RBSD) control method and system for a vehicle anti-lock brake system (ABS) having a brake switch. The control method includes generating a RBSD control signal when the brake switch is inoperative, and performing RBSD control of the ABS in response to the RBSD control signal. The control system includes wheel speed sensors, ABS control valves, and a programmable microprocessor ABS control unit for performing the control method.

Reduced brake switch dependence control method and system for vehicle

The method and system for controllably restricting the on time of a pump of an electro-hydraulic control system for a hydraulic brake system by modeling the amount of hydraulic brake fluid in a low pressure accumulator (LPA) of the hydraulic brake system. Sensors sense wheel speed of their respective wheels of a vehicle. Control valves, including isolation and dump valves, together with the pump, vary the amount of brake fluid in the LPA. A control unit electrically coupled to the pump, the control valves and the wheel speed sensors, initially detects an electro-hydraulic control event based on the sensed wheel speeds and then activates the control valves and pump which vary the amount of brake fluid in the LPA. The control unit models the amount of brake fluid in the LPA during the activation and controls the state of the pump based on the modeled amount of brake fluid in the LPA. The modeled amount of brake fluid in the LPA consequently is based on the on time of the pump and the total on time of all of the dump valves in the electro-hydraulic control system.

Method and system for controllably restricting the on time of a

A method and system for modifying anti-lock brake control to a vehicle experiencing drivetrain-induced oscillations. A wheel speed of each of the wheels is sensed to generate a corresponding speed signal. A drivetrain-induced oscillation condition is detected in one of two ways. First, a wheel speed peak count is determined for each of the wheels. A drivetrain-induced oscillation is then detected if multiple peaks occur within a predetermined period of time. Alternatively, a frequency of oscillation for each of the wheel speeds is determined and compared to a predetermined frequency threshold. Upon determining that the vehicle is experiencing drivetrain-induced oscillation during an ABS event, brake pressure is applied to the driven wheels at approximately the same frequency as the frequency of oscillation of the drivetrain-induced oscillation.

Growing community of inventors

Ann Arbor, MI, United States of America

Mark S Luckevich