Kelsey-hayes Company

Mark D Lubbers

Richard J Barron

Gregory J Krawczyk

Herbert L Linkner, Jr

Edward Nelson Fuller

Harry A Hunnicutt

Danny R Milot

Gerald M Sivulka

Arnie Spieker

Louis S Tang

Michael O'Connor

Stephen H Youtsey

A method is provided for detecting a fault condition in a hydraulic brake system of a vehicle having a first hydraulic brake circuit and a second hydraulic brake circuit. A correlation ratio is determined between a measured pressure and the actual vehicle acceleration. A first wheel velocity differential is determined and a second wheel velocity differential is determined. A weighting value is selected in response to determining whether the correlation ratio is within the predetermined range and whether the first wheel velocity differential and the second wheel velocity differential are opposite signs. The selected weighting value is added to a fault counter. A determination is made whether the fault counter is equal to or greater than a predetermined threshold. A fault condition is detected in response to the fault counter greater than or equal to the first predetermined threshold.

Method for detecting brake circuit failure

An algorithm for limiting the output of a master cylinder pressure sensor in an electronic brake control system to a value that is a function of the master cylinder pressure and the travel of the brake pedal.

Method and device for limiting the output signal of a sensor to reduce noise

A method is provided for controlling the braking of a vehicle that has a first set of friction brakes for applying a first apply brake force to a first set of wheels and a second set of friction brakes for applying a second brake apply force to a second set of wheels. A powertrain assembly is coupled to the second set of wheels. The powertrain assembly includes a regenerative braking unit capable of recapturing kinetic energy from the second set of wheels. The vehicle is braked in a first phase of control using regenerative braking to brake the second set of wheels to achieve up to a first value of braking. The vehicle is braked in a second phase of control using the regenerative braking to maintain braking of the second set of wheels at the first value of braking force while selectively applying the first friction brakes to the first set of wheels up to a second value of braking.

Vehicle system having regenerative brake control

A vehicle hydraulic system is disclosed comprising a hydraulic fluid reservoir; a pressure force supplying pressurized hydraulic fluid to a discharge header; a fluid conduit between the discharge header and the reservoir; a back pressure valve operative in the fluid conduit to maintain a desired pressure in the discharge header; and a vehicle braking system having a hydraulically operated boost piston assembly for supplementing a force exerted by a vehicle operator to operate brakes of the vehicle braking system. The system further includes a boost pressure control valve responsive to an input from the vehicle operator for selectively directing pressured hydraulic fluid from the discharge header to the boost piston assembly and venting hydraulic fluid from the boost piston assembly to the reservoir.

Electronically controlled hydraulic brake boost pressure control system

A vehicle hydraulic system is disclosed comprising a pressure source supplying pressurized hydraulic fluid to a discharge header, a vehicle braking system having a hydraulically operated boost piston assembly for supplementing a force exerted by a vehicle operator to operate brakes of the vehicle braking system; a boost pressure control valve for selectively directing pressurized hydraulic fluid from the discharge header to boost piston assembly and venting hydraulic fluid from the boost piston assembly; and a sensor for receiving an input from a vehicle operator and supplying an electrical signal to the boost pressure control valve to control the operation thereof.

Hydraulic brake booster

A method of controlling the operation of an electrohydraulic brake booster to achieve a desired pedal feel. The method includes sensing brake pedal movement from a fully retracted rest position before a significant resistance to travel of the brake pedal is developed. The method further includes generating a command pulse that results in application of pressurized hydraulic fluid to the boost piston assembly sufficient to overcome preloaded spring forces and seal friction in the boost piston assembly that would otherwise tend to resist further brake pedal travel. The method further includes providing a control signal override when a brake pedal 'bounce' condition is detected to avoid undesired vehicle braking. A brake pedal bounce condition may occur if the brake pedal is released suddenly so that the brake pedal returns to the fully retracted rest position rapidly enough to bounce off of a mechanical stop at that position and move in the brake apply direction.

Electrohydraulic brake booster and method of controlling same for smooth

A brake booster for a brake system of a vehicle, wherein the brake booster is in fluid communication with a source of pressurized fluid. The brake booster includes a housing having a bore formed therein and a conduit formed therein being in fluid communication with the bore and the source of pressurized fluid. The brake booster includes first and second pistons slidably disposed within the bore of the housing. The bore, the first piston, and the second piston define a fluid chamber in fluid communication with the conduit formed in the housing, wherein the volume of the chamber is defined by the position of the first piston relative to the second piston. The brake booster further includes a valve selectively preventing fluid flow in a direction from the chamber to the source of pressurized fluid via the conduit.

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Ann Arbor, MI, United States of America

Mark D Lubbers