Lucas Industries Public Limited Company

Lucas Industries Limited

Mark Ian Phillips

Alan Leslie Harris

Mark Leighton Howell

Malcolm Brearley

Peter Martin

Colin F Ross

Anthony John Ainsworth

John Anthony Bolton

Robert D Prescott

Karl Friedrich Worsdorfer

A method of detection and identification of pressure sensor faults in an electro-hydraulic braking system of the type comprising a brake pedal, respective braking devices connected to the vehicle wheels and which communicate with electronically controlled proportional control valves in order to apply hydraulic fluid under pressure to the braking devices, respective pressure sensors for measuring the hydraulic pressures at the individual braking devices, a hydraulic pump driven by an electric motor, a high pressure hydraulic pressure accumulator fed by the pump for the provision of hydraulic fluid under pressure which can be passed to the braking devices via the proportional control valves in order to apply hydraulic fluid under pressure to the braking devices in proportion to the driver's braking demand as sensed at the brake pedal, and a supply pressure sensor for monitoring the hydraulic pressure supplied to the electronically controlled proportional control valves. In accordance with the method, three or more of the pressure sensors are arranged to be subjected to the same pressure and their readings measured and compared whereby to identify a sensor whose reading does not correspond to that of the others.

Detection and identification of pressure-sensor faults in electro-hydraulic (EHB) braking systems

A vehicle hydraulic braking system of the brake-by-wire type is disclosed in which proportional solenoid-operated valves (12, 13) are adapted to control the pressure in wheel brake actuators of the brakes (8, 9) on a single axle of a vehicle, and a balance valve (20) is provided to enable individual hydraulic brake circuits to be hydraulically connected so that the pressure applied to each brake is guaranteed to be substantially the same, a first one (13) of the proportional valves (12, 13) is adapted to be isolated so that the hydraulic circuit is fed by a second, single, proportional valve (12). Applying both brakes under the control of a single proportional valve ensures that any fluid leakages are balanced since substantially equal brake-applying pressures are generated. An alternative vehicle hydraulic braking system of the brake-by-wire type is also disclosed in which a control module (3) is provided which is adapted to select between at least a first control mode (104) in which more than one of the proportional valves (12, 13) is adapted to be controlled in parallel and a second control mode (103) in which only one of the proportional valves (12, 13) is operated to control the pressure in the wheel brake actuators.

Vehicle hydraulic braking systems of the brake-by-wire type

Anti-lock braking system having pulsed pressure re-application

Anti-lock braking systems (ABS) for road vehicles to avoid premature

In a control system, for instance forming part of a vehicle anti-lock brake system, a plurality of control processors provides similar or identical control signals of the system in response to a shared transducer input. An independent data correlation processor compares data generated in the control processors for correlation and, in the absence of proper correlation, provides an indication which may be used to disable anti-lock operation of the brake system. In preferred embodiments, a four wheel vehicle with an anti-lock brake system is monitored by dual microprocessors. Each wheel has a speed sensor which supplies an input to each microprocessor. The data correlation processor compares the outputs of the microprocessors for each wheel and sends and alarm or disables the anti-lock brake system if the difference in the microprocessors output is beyond a limit amount.

Control system having data correlation for controlling a vehicular

An anti-lock ABS braking system for a road vehicle includes a respective dump valve for each brake actuator which enables pressure to be selectively dumped from that actuator to release the braking action of the relevant rear wheel. Whether a given rear wheel of the vehicle is still operating in a stable condition is established, as is the aggregate dump valve time of the rear wheel opposite to that under consideration. The brake pressure at the still stable rear wheel is allowed to continue to rise for a prescribed period and then its dump valve is actuated for a period corresponding to the measured aggregate dump time of the opposite rear wheel.

Asynchronous rear dump logic in ABS control systems

An ABS skid detection protection system for a wheeled vehicle detects a predetermined level of deceleration at a wheel; detects, memorizers and holds for a prescribed period the wheel speed value at that predetermined deceleration level; detects whether the angular acceleration of the monitored wheel first falls below and then re-establishes the predetermined deceleration level within the prescribed level; and corrects the memorizsed value of wheel speed by subtracting from it an amount equal to the vehicle deceleration multiplied by either the elapsed time since the wheel speed value was memorized or the elapsed time since the initiation of a short-duration pulse by which the actuating pressure applied to a brake can be temporarily dumped upon detection of the predetermined level of deceleration of the wheel.

Protecting ABS skid detection against data corruption

An anti-skid braking system for wheeled vehicles having fluid actuated brakes associated with the vehicle wheels, speed sensors associated with the vehicle wheels and a cyclically operating control device which is responsive to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined to be about to lock and to later re-apply the actuating pressure to that brake when the tendency of that wheel to lock has reduced, and wherein the pressure dump phase is arranged to be cancelled during wheel-lock when the aggregate dump time for the current cycle exceeds a limit value based upon a weighted-average dump time of previous cycles.

Locked wheel reapply in ABS control systems

An anti-skid braking system for a vehicle comprising a supply of fluid for actuating a plurality of wheel brakes, a skid control unit interposed between the fluid supply and the brakes, sensors to detect the skidding of a plurality of wheels and actuating means responsive to skid signals from the sensors and adapted to actuate the skid control unit to relive the fluid pressure at the brake of the wheel at impending lock by means of a plurality of successive first brake release periods. In order to reduce yawing, when an impending skid condition is detected at one wheel, the skid control unit is arranged to induce second, shorter brake release periods in one or more of the brakes of the wheels not at impending lock.

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Birmingham, United Kingdom

Mark Ian Phillips