Lucas Industries Public Limited Company

Lucas Industries Limited

Sean Byrnes

John P Bayliss

Ivan Mortimer

Colin McDonald

Frank J Bagley

Vehicle brake servo booster with traction control mode

In a hydraulic system for traction control, a pump is adapted to withdraw fluid from a reservoir through a master cylinder assembly under the control of a solenoid-controlled valve responsive to signals from an electronic control module, and a pressure-sensitive valve. The system is also provided with a solenoid-controlled flow control valve also responsive to signals from an electronic control module, a switch is responsive to movement of the throttle of the engine of a vehicle, and from which signals are transmitted to the control module. Thus, when the signal from the switch changes as the foot is released from the throttle pedal, the control module recognizes the change in signal and re-sets the modulator means, for example the solenoid-operated flow control valve.

Hydraulic systems for vehicles

The present specification discloses a servo unit for use in a vehicle braking system, the servo unit comprising a housing within which a flexible diaphragm separates a vacuum pressure chamber from an atmospheric pressure chamber. An actuator rod assembly extends through the housing and includes a valve assembly having a valve control piston which has a laterally extending key, the key being engageable with a fixed stop in the housing to limit the movement of the valve control piston and cause a balance in the valve assembly between the vacuum and atmospheric pressure. A solenoid valve is also provided, the solenoid valve being controllable to either connect a flexible passage member extending around the actuator rod assembly across the vacuum pressure chamber between the housing and the diaphragm in the region of the valve assembly, to the vacuum pressure chamber, or to connect both the flexible passage member and a bypass leading from the solenoid valve to the atmospheric pressure chamber, to the atmosphere. The bypass incorporates a one-way valve.

Vacuum servo unit for use in traction control

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Birmingham, United Kingdom

Sean Byrnes