Position sensing transducer

An internal combustion engine provided with a displacement transducer for monitoring the angular rotation of the engine, the displacement transducer comprising:

• a rotary disc provided with a castellated periphery and mounted for rotation with the engine;
• first and second coils mounted on the engine, said coils being spaced apart from one another for inductive coupling therebetween and such that upon rotation of the engine the castellations of the disc interrupt said coupling;
• means arranged to supply to a first of said coils an oscillatory electrical signal whereby to induce in the second of said coils an output signal of a first peak amplitude during the said interruptions produced by said castellations of the disc and of a second peak amplitude during periods between said interruptions;
• means responsive to said output signal for producing a control signal of a magnitude which is representative of an average of said first and second magnitudes;
• and
• a comparator arranged to compare the peak magnitude of said output signal with said control signal whereby to provide an indication of the commencement and cessation of said interruptions.

An electrical displacement transducer comprising:

• spaced apart transmitting and receiving means for respectively transmitting energy and receiving said energy;
• a member for being moved between said transmitting and receiving means, said member interrupting repetitively the passage of said energy from said transmitting means to said receiving means as a function of the movement of said members between said means;
• said receiving means producing an electrical output signal which assumes a first magnitude during said repetitive interruptions and a second different magnitude for periods between said interruptions;
• and
• output means for producing an output indicative of when said signal exceeds a magnitude representative of an average of said first and second magnitudes whereby to provide an indication of the commencement and cessation of said interruptions.

An electrical displacement transducer comprising:

• spaced apart transmitting and receiving means for respectively transmitting energy and receiving said energy;
• a member for being moved between said transmitting and receiving means, said member interrupting repetitively the passage of said energy from said transmitting means to said receiving means as a function of the movement of said members between said means;
• said receiving means producing an electrical output signal which assumes a first magnitude during said repetitive interruptions and a second different magnitude for periods between said interruptions;
• and
• output means for producing an output indicative of when said signal exceeds a magnitude representative of a predetermined portion of said first and second magnitudes whereby to provide an indication of the commencement and cessation of said interruptions.