Kelsey-hayes Company

Edward R Hornback

Clark E Lowman

Mark S Luckevich

Gregory P Campau

Paul M Schliebe

Charles Darnell

John D Cotner

A signal conditioning circuit is provided for a plurality of pressure signals generated by individual pressure sensors mounted upon a hydraulic control valve. The signal conditioning circuit sequentially samples each of the pressure sensors and multiplexes the individual pressure signals into a single analog pressure signal. The signal conditioning circuit includes a differential amplifier that is compensated for offset and linearity as a function of which particular pressure sensor is being sensed.

Circuit for compensation of a transducer output signal

A plurality of pressure sensors are carried in housing mounted upon a hydraulic control valve for an electro-hydraulic brake system. The pressure sensors are electrically connected to a signal conditioning circuit which also is mounted upon the hydraulic control valve. The signal conditioning circuit samples the sensors and mulitplexes the sensor signals into a single output signal.

Structure for mounting a cluster of pressure sensors upon an electro-hydraulic brake system control unit

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

Test signals are generated by a microcontroller (i.e., micro) and coupled to a transistor which is in series with an inductive sensor of a wheel speed sensor input circuit to test the input circuit. In one test, a test signal from the micro sweeps through a range of predetermined frequencies to turn the transistor off and on to provide a simulated wheel speed signal which is used to compute a corresponding number of simulated wheel speeds. The programmed micro compares the simulated wheel speeds with the predetermined frequencies to determine if the various components of the circuit are operating properly and also to determine if the wheel speed arithmetic of the programmed micro is operating properly since actual wheel speed routines within the micro are used to compute the simulated wheel speeds. In another test, a low pass filter circuit coupled to an A to D input port of the micro are both tested by having the micro read the input port at various times before and after a second test signal from the micro is coupled to the transistor.

Method and system for testing a wheel speed sensor input circuit in an

A method and apparatus for detecting the proper functioning of an ABS control unit which utilizes dual programmed microprocessors, the second of which calculates mismatched wheel speed and both of which calculate extended control loop time. When computed wheel velocities are above 10 mph, the second microprocessor determines whether the difference in computed wheel velocity between the two microprocessors is at least 2 mph. If the difference is more than 2 mph for more than 6 consecutive program loops, a mismatched wheel speed calculation error is identified. Each of the microprocessors also compares its loop timing with the loop timing of the other microprocessor and if more than 1 millisecond late for 6 consecutive program loops, the proper diagnostic response is to set an ignition latch code which triggers an inhibit signal. In addition, if the first microprocessor determines more than a 16 millisecond delay, then the first microprocessor is reset. If the second microprocessor determines more than a 65 millisecond delay, then the second microprocessor is reset.

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Dexter, MI, United States of America

Edward R Hornback