Motorola Corporation

James W Kopec

Donald W Zerrien

Robert W Deutsch

Gerald M Hirka

Philip Herbert

Measurement of fluid flow (or other fluid parameter) through a solenoid-actuated valve (12), and/or measurement of nominal operation of the valve itself, is achieved in one embodiment by modifying the amplitude of flyback pulses (48) generated by the solenoid. The degree of modification preferably varies with the value of the sensed information, and the modified flyback pulses are processed to extract that information from diagnostic and/or control purposes. In another embodiment, a variable impedance is established in the path of the solenoid's recirculation current. For a fraction of the solenoid's recirculation period, the impedance is caused to vary as a function of the value of the sensed information. For the remainder of the recirculation period, the value of the impedance is greatly reduced to maintain the recirculating current at a relatively high level.

Solenoid controller with flyback pulses useful for diagnostics and/or

A method and apparatus for electronically detecting when a solenoid has closed, or nearly closed, indirectly senses changes in the inductance of the solenoid's coil as the solenoid closes. When the inductance has changed by a selected amount, the solenoid is assumed to have closed, or nearly closed, and current through the coil is promptly reduced. Preferably, changes in the inductance of the coil are sensed by establishing a plurality of current peaks in the coil, and sensing the current's decay time between peaks. When the decay time of a measured current peak exceeds the decay time of a previously measured current peak by a selected amount, it is assumed that the solenoid has closed, or nearly closed.

Solenoid closure detection

An angle measuring device is described for accurately indicating the position of the rotor relative to the reference position in view of perceived changes of rotor speed. The measuring device includes a sensor for detecting the markings and generating a sensor signal in response thereto; an angle counter, responsive to the sensor, for generating a position signal; and a correction circuit, responsive to the sensor signal, for correcting the position signal. The position signal is corrected in response to the sensor signal so as to provide an accurate indication of the position of the rotor.

Bounded synchronous angle counter

In one aspect of the present invention, an angle measuring device is described for measuring the angle of a rotating rotor having a plurality of markings spaced thereabout. The device comprises: a sensor positioned adjacent the rotor for detecting the markings and generating a sensor signal in response thereto; an indicator device, responsive to the sensor signal, for generating a position signal indicative of the angular position of the rotor. Additionally, a timing circuit is used for measuring the time between contiguous sensor signals; and a comparator is used for comparing at least one of the measured times against at least one predetermined value and for generating a comparison output signal indicative thereof. Finally, a correction circuit is used, in response to the comparison output signal, for correcting the position signal to avoid inaccuracies due to such problems as unequal spacing between the markings.

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St. Charles, IL, United States of America

James W Kopec