Throttle-position sensor for an electronic fuel- injection system

Abstract From the Canadian patent

Interpreted intake-manifold vacuum and engine speed are used to produce an electrical output signal that reflects throttle position. Since the device has no mechanical tie to the throttle, there is none of the hysteresis or mechanical wear that are characteristic of conventional throttle-position sensors. The device comprises a tachometer circuit which is modulated by the signal from a differentialpressure transducer, connected to track the instantaneous hydraulic pressure drop across the engine throttle. The tachometer output controls the duty cycle of a pulse generator which, in turn drives an, output transistor; a reference potential is applied across the load resistor and emitter of …