Sun Electric Corporation

Zoltan Voross

James R Caruth

Yam C Leung

An apparatus for measuring the dwell of an automobile ignition system is disclosed. The dwell measuring apparatus is applicable to conventional and solid state ignition systems. The apparatus analyzes the primary coil ignition waveform and generates a signal proportional to the dwell ratio, based upon the amount of time the primary voltage is approximately zero.

Apparatus for measuring the dwell of an automotive ignition system

The disclosure describes apparatus for disabling selected cylinders of an internal combustion engine operated by periodic cycles of ignition signals. The apparatus prevents one or more predetermined ignition signals in each cycle from energizing engine components, such as spark plugs, which normally receive the ignition signals. In order to achieve this purpose, a clock pulse generator generates a uniform pulse in response to the receipt of each ignition signal from the engine. Three bistable flipflop circuits are used to produce output signals having states representative of the number of clock pulses received from the clock pulse generator. Gating circuitry returns the output signals to an initial state after receipt of a predetermined number of clock pulses, such as the number of cylinders in the engine being diagnosed. As the apparatus commences operation, removable setting means set the output signals to their initial state by means of a setting pulse generated by one of the ignition signals. The repetition rate of the setting pulse is divided before being applied to the flipflop circuits in order to improve the diagnostic usefulness of the system. The transmission of the setting pulse also is delayed so that the output signals normally are returned to their initial state by the gating circuitry and clock pulses prior to the time the setting pulse is received by the flipflop circuits. A selecting circuit generates a disabling pulse in response to a predetermined state of the output signals. The disabling pulse switches a disabling device, such as a triac, to a conductive state to prevent a predetermined ignition signal from firing a selected spark plug, thereby aiding the diagnosis of the engine.

Signal disabling engine diagnosing apparatus

The automatic output zeroing apparatus includes an energy storage device and a differential operational amplifier. The energy storage device, which is connected to one input of the differential operational amplifier, is charged to a voltage representing the free air voltage generated by the exhaust emission analyzer. The other input of the differential operational amplifier receives the pollution-indicating voltage generated by the exhaust emission analyzer. The differential operational amplifier produces a modified pollution-indicating voltage, representing the difference between the generated pollution-indicating voltage and the free air voltage.

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Elgin, IL, United States of America

Zoltan Voross