Borg-warner Automotive Gmbh

Thomas D Herrington

Lee A Naffziger

Michael J Covey

A solenoid exhaust gas recirculation (EGR) valve (12) includes a first inductive coil (48) that generates a magnetic field when energized by a signal from a control unit (13). The magnetic field drives a ferromagnetic armature valve (64) open and closed--metering the flow of recovered exhaust gases from an engine exhaust manifold (14) to an engine air intake manifold (16). The exhaust gas flow rate depends upon the amount of current flowing through the first coil (48). The resistance of the first coil (48) is temperature-dependent. Therefore, to reduce changes in coil current and magnetic field strength due to temperature changes, the first coil (48) is connected in series with a thermistor (75) having a temperature coefficient of resistance that is opposite that of the first coil (48). A temperature stable resistor in the form of a second coil (72) is connected across the thermistor (75) to modify the thermistor temperature-response curve to more closely offset that of the first coil (48). The second coil (72) may be disposed adjacent the first coil (48) to generate a magnetic field opposite that of the first coil (48). The opposing field reduces residual magnetism causing the valve (12) to respond to control inputs more positively.

Temperature-compensated exhaust gas recirculation system

A composite check valve and positively closing electromagnetic solenoid valve, particularly such a valve for regulating the introduction of secondary air into the exhaust stream of an internal combustion engine at selected times during the operation of the engine. The valve comprises an inlet port, an outlet port, a first valve element movable between open and closed positions for nominally regulating the flow of a fluid between the inlet and outlet ports, and an electromagnetic solenoid having a closure element for overriding the first element. The rigid disk or closure element can function by seating against the same seat as the first element, or by 'latching' the first element in its closed position. The disclosed embodiment is a flap valve which is modified by superimposing a rigid, movable valve disk over the flap. The rigid disk is connected to the solenoid armature and is movable between an override (closed) position and a disengaged (open) position when the solenoid is energized. The rigid disk may also limit the opening of the flap to regulate the rate of fluid flow through the valve.

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Dixon, IL, United States of America

Thomas D Herrington