Alliedsignal Truck Brake Systems Company

Cheryl L Greenly

Robert D Krieder

Tamas I Pattantyus

Ronald E Squires

A supervisory circuit for an anti-lock brake system (ABS) unit. The circuit includes an independent internal voltage reference source that provides power to the circuit components. The circuit also includes an external power source monitor powered by the internal voltage reference source which inhibits the ABS unit when an external power source voltage exceeds a predetermined level. The circuit also includes a system voltage monitor powered by the internal voltage reference source that inhibits the ABS unit when a system voltage deviates from predetermined system voltage parameters. The circuit also includes an electronic control unit (ECU) monitor powered by the internal voltage reference source that monitors a periodic signal generated by an ECU and that inhibits the ABS unit if an ECU timing signal deviates from a predetermined threshold level. The supervisory circuit helps to prevent spurious operation of ABS modulators due to race conditions.

Supervisory integrated circuit for anti-lock brake system units

An electronically controlled compressed air system (10) includes an air dryer (16) which dries compressed air before the compressed air is communicated to a reservoir (26). The air dryer (16) includes a desiccant (18) which is purged by using air stored in the reservoir (26). A pressure transducer (13) is installed on the reservoir (26) and transits an electrical signal, indicative of the pressure in the reservoir (26) to an electric controller (11). Electric controller (11) transmits signals at various selected pressure levels to solenoid value (28) to control loading and unloading of the compressor (12), to solenoid valve (36) to control purging of the air dryer (16), and to the warning light (40) to alert an operator of a low air pressure condition. The valve (36) is operated to permit purging only when the compressor (12) is unloaded and only until a reservoir pressure is reached which is a predetermined pressure drop below the reference pressure level at which the compressor (12) is unloaded, whereupon purging is terminated.

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Elyria, OH, United States of America

Cheryl L Greenly