Automotive stall circuit
AssigneeMotorola, Inc.
InventorJames J. Lo Cascio
Life of this patent
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Abstract
A stall circuit is described for use in combination with an electronic adaptive dwell ignition system which allows an ignition coil to be de-energized whenever the frequency of operation of the ignition system decreases below a specified frequency without causing a spark to be generated in the engine of an automobile controlled by the ignition system while allowing continued operation of the ignition system to generate a spark in response to a spark command being generated with minimum spark retard.
Claims10
A stall circuit to be utilized in combination with an adaptive dwell electronic ignition system operated in timed relationship to an engine, comprising:
- first circuit means coupled to a first circuit node for providing a reference potential thereat;
- and
- second circuit means having an input coupled with the ignition system and an output which is responsive to the magnitude of an input signal supplied thereto being greater than said reference potential for producing an output signal the magnitude of which is proportional to said reference potential, said second circuit means being responsive to said magnitude of said input signal being less than said reference potential for producing an output signal that is proportional to said magnitude of said input signal.
In an adaptive dwell ignition system including a dwell circuit for generating control signals in response to receiving timing signals supplied thereto that are generated in timed relationship to an engine rpm, current limiting circuitry responsive to the control signals for producing current to charge and then discharge an ignition coil accordingly, a stall circuit comprising:
- first unity gain comparator means having an input coupled with the dwell circuit and receiving an input signal the magnitude of which is controlled by the dwell circuit, said first unity gain comparator means providing an output signal at an output the magnitude of which is proportional to said input signal magnitude;
- first diode means coupled between said output of said first unity gain comparator means and a first circuit node;
- first circuit means coupled to said first circuit node for producing a reference potential thereat;
- and
- second unity gain comparator means having an input coupled to said first circuit node and an output coupled to an input of the current limiting circuit, said second unity gain comparator means being responsive to said magnitude of said output signal of said first unity gain comparator means being less than said reference potential by a predetermined amount for producing an output signal the magnitude of which is proportional to said magnitude of said output signal of said first unity gain comparator means and being responsive to said magnitude of said output signal of said first unity gain comparator means being greater than said reference potential for producing an output signal the magnitude of which is proportional to said reference potential.
Dependencies are inferred from the claim text.