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INTERNAL COMBUSTION ENGINE IGNITION TIMING INSTRUMENT

  • US 3,775,672 A
  • Filed: 09/25/1972
  • Issued: 11/27/1973
  • Est. Priority Date: 09/25/1972
  • Status: Expired due to Term
First Claim
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1. An internal combustion engine ignition timing instrument comprising:

  • means for prodUcing a primary signal each time an ignition spark is generated for said engine;

    means for producing a TDC signal when the reference cylinder of said engine is at the top dead center position;

    circuit means responsive to said primary signals for producing an ignition signal when an ignition spark potential is generated for the reference cylinder of said engine;

    circuit means responsive to said TDC and ignition signals for producing a series of timing angle signal pulses each of a width equal to the period between said TDC and ignition signals when the ignition spark is retarded and to the period between said ignition and TDC signals when the ignition spark is advanced;

    circuit means responsive to said timing angle signal pulses for producing a direct current timing angle potential signal of a selected one polarity when the ignition spark is retarded and of the opposite polarity when the ignition spark is advanced and of a magnitude porportional to the number of degrees of ignition spark retard or advance;

    means for producing a direct current timing angle high reference potential signal and a direct current timing angle low reference potential signal of selected respective magnitudes greater than and less than the magnitude of said timing angle potential signal at a selected number of degrees of ignition spark retard or advance;

    first circuit means responsive to said timing angle potential signal and said timing angle high reference potential signal for producing a logic output signal of a selected polarity when the magnitude of said timing angle potential signal is greater than and a logic output signal of another polarity when the magnitude of said timing angle potential signal is less than the magnitude of said timing angle high reference potential signal;

    second circuit means responsive to said timing angle potential signal and said timing angle low reference potential signal for producing a logic output signal of a selected polarity when the magnitude of said timing angle potential signal is greater than and a logic output signal of another polarity when the magnitude of said timing angle potential signal is less than the magnitude of said timing angle low reference potential signal, and logic circuit means responsive to a logic output signal of said selected polarity from both said first and second circuit means for producing a logic output signal of a selected polarity indicating that the ignition spark is advanced;

    to a logic output signal of said other polarity from both said first and second circuit means for producing a logic output signal of a selected polarity indicating that the ignition spark is retarded and to a logic output signal of said selected polarity from said first circuit means and a logic output signal of said other polarity from said second circuit means for producing a logic output signal of a selected polarity indicating that the engine is properly timed.

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