US 4,066,054 A · Transducer circuits

Abstract

An electronic engine spark timing controller contains a throttle position transducer circuit and an intake manifold vacuum transducer circuit which provide respective signals representing the throttle position and the magnitude of intake manifold vacuum. Each of these two circuits contains a novel configuration of electronic circuit elements to develop an output electrical waveform composed of repetitive pulses each of which has a pulse width representative of the corresponding mechanical input signal which is supplied to the circuit via a transducer in the form of a coil whose inductance is varied in accordance with the mechanical input signal. The coil in each transducer circuit forms a portion of an RL type monostable circuit which exhibits an electrical transient when triggered. Both transducer circuits are triggered from a free-running pulse generator which is set to generate pulses at a fixed frequency. The pulse width of the trigger pulses used to trigger the transducer circuits is appreciably less than the pulse width of the output pulses of the transducer circuits, and each transducer circuit contains a feedback circuit which, when the monostable has been triggered by a pulse from the pulse generator, enables the electrical transient generated therein to continue. The output signals are used in conjunction with additional circuitry to provide spark timing control for the engine.

Claims8

Dependent claims

In combination:

an internal combustion engine whose operation is controlled in accordance with a pair of mechanical input signals, each of which is representative of a corresponding engine operating parameter;
an oscillator circuit comprising means for generating trigger pulses at a substantially constant triggering frequency which is independent of engine speed;
a first monostable circuit which is operatively coupled with said oscillator circuit to receive each said trigger pulse and is immediately tripped upon receipt thereof into its unstable state to develop a first rectangular signal waveform having a frequency exactly equal to that of said trigger pulses and an average value representative of one of said mechanical input signals;
a second monostable circuit which is operatively coupled with said oscillator circuit to receive each said trigger pulse and is immediately tripped upon receipt thereof into its unstable state to develop a second rectangular signal waveform having a frequency exactly equal to that of said trigger pulses and an average value representative of the other of said mechanical input signals;
first averaging circuit means coupled with said first monostable circuit for averaging said first waveform;
second averaging circuit means coupled with said second monostable circuit for averaging said second waveform;
and means responsive to the two averaged signals of said first and second averaging circuit means for controlling operation of the engine.

4 more elements

Dependencies are inferred from the claim text.

Transducer circuits

Life of this patent

Transducer circuits

Life of this patent

Abstract

Claims8