Hughes Microelectronics Limited

Ranco Inc.

Albert L Fowler

Alastair K Stevenson

David M Walker

Alan G Henderson

Robert F Purssell

Alan Pelczyk

Alfred J Woollard

A displacement-measuring transducer has a laminar member displaceable, for example under control of a vacuum actuator, within a housing containing respective pairs of coils spaced part in the displacement direction of the laminar member, which is provided with two apertures spaced apart in the said direction, such that the coupling between the coils of each pair is dependent upon the position of said apertures and, therefore, on the displacement of the laminar member.

Displacement measuring transducer

A displacement transducer suitable for monitoring the angular rotation of an internal combustion engine is provided. The transducer comprises a rotary disc having a castellated periphery and mounted for rotation with the engine. First and second coils are mounted such that upon operation of the engine the castellations of the disc interrupt the inductive coupling therebetween. The first coil is fed with an oscillatory electrical signal which induces in the second coil an output signal of a first peak amplitude during the interruptions produced by the castellations and of a second peak amplitude during periods between the interruptions. Thresholding circuitry responsive to the output signal produces a control signal which is indicative of the commencement and cessation of the interruptions. In accordance with one disclosed embodiment, the threshold circuitry includes a pair of inverters sharing the same thermal environment. The first inverter is capacitively coupled to receive the output signal from the second coil, and the second inverter, which has its output connected to its input in a feedback arrangement, provides bias through a resistive coupling to the first inverter to compensate for temperature drifts, whereby the first inverter switches output signal states when its input signal passes through a preselected voltage level.

Position sensing transducer

The invention concerns an internal combustion engine provided with a vacuum sensor for monitoring the level of partial vacuum in the engine's inlet manifold, in order to provide an indication of engine load. during changes in engine load, the level of partial vacuum presented to the vacuum transducer is modified from that obtaining in the inlet manifold in order to improve the accuracy of the output of the transducer during changes of engine load.

Vacuum sensor

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Kirkaldy, United Kingdom

Albert L Fowler