United Technologies Automotive Inc.

United Technologies Corporation

Ronald C Nonnenmacher

Richard C Lewis

Richard C Riley

Kathleen Schulz

David V Tinder

A variable power resistor includes a heat sink having a front face and a back face with an electrically insulating, thermally conductive ceramic coating bonded directly onto the front face such that the ceramic coating is in direct thermal contact with the heat sink. A plurality of discrete thick film conductive circuit pads are positioned on the electrically insulating, thermally conductive ceramic coating and a thick film resistive layer is positioned over portions of the conductive circuit pads such that the pads are electrically connected in series. The variable power resistor also includes a moveable contactor capable of contacting the circuit pads in order to vary the resistance of the resistor and an electrical connection between the resistor and an electrical circuit. The electrically insulating, thermally conductive ceramic coating may be plasma sprayed onto the heat sink, while the resistive circuit may be screen printed onto the ceramic coating.

Method of making a variable power resistor

Variable power resistor

A method and apparatus is provided for measuring the hysteresis error of a position sensor for a reciprocating element, such as the sensor for determining piston TDC in a reciprocating engine. The sensor is of the proximity type and has a sensing region past which a vane relatively moves. Event timing signals are provided by voltage transitions occasioned by the leading and trailing edges respectively of the vane passing the sensor. The method includes moving a pair of test vanes in opposite directions past the sensor to simulate two passes thereby of a reciprocating vane to generate the event timing signals from the sensor. This may be done by mounting the test vanes on a pair of rotating discs. Independently of the sensor, reference timing signals are generated which are accurately indicative of the positioning of the leading and trailing edges of the one or more test vanes. These reference timing signals may be determined optically. An event timing signal is then compared with a respective corresponding reference timing signal for each of two of the reference timing signals symmetrically disposed with respect to the position to be determined, i.e. TDC, and a difference value is determined for each of those two comparisons. Finally, the two difference values are compared to determine a further difference value, that further difference value being a measure of the hysteresis error.

Method and apparatus for measuring hysteresis of a position sensor

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Apache Junction, AZ, United States of America

Ronald C Nonnenmacher