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Engine combustion control responsive to location and magnitude of peak combustion pressure

  • US 4,706,628 A
  • Filed: 12/29/1986
  • Issued: 11/17/1987
  • Est. Priority Date: 12/29/1986
  • Status: Expired due to Fees
First Claim
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1. A combustion control for an internal combustion engine of the type having a plurality of combustion chambers, means for supplying a combustible charge to and igniting the combustible charge within each combustion chamber, power output apparatus including a rotating crankshaft, and means for sensing the crankshaft angle (LPP) and magnitude (MPP) of peak combustion pressure for each combustion chamber, the combustion control comprising, in combination:

  • means for deriving the average magnitude of peak combustion pressure (AMPP) for all combustion chambers;

    means for determining, from the sensed values of predetermined engine operating parameters, base values for the combustible charge mixture and ignition timing, relative to the rotating crankshaft, for each combustion chamber;

    memory means for storing tables of LPP ignition trim values, MPP ignition trim values and A/F trim values for each combustion chamber as a function of predetermined ranges of at least some of the predetermined engine operating parameters, the LPP and MPP ignition trim values having predetermined limits;

    means for comparing the sensed LPP value for each combustion chamber with a desired LPP value (DLPP) for that combustion chamber and adjusting the LPP ignition trim value for the predetermined engine operating parameters, up to the LPP ignition trim value limit, in the direction to reduce the difference therebetween at least to a predetermined allowable LPP range;

    means for comparing the MPP value for each combustion chamber with the average magnitude of peak combustion pressure for all combustion chambers (AMPP) and determining whether the difference is within a predetermined allowable MPP range;

    means effective, if the MPP value is too low for the allowable MPP range and the MPP ignition trim value is at the MPP ignition trim value limit in the advance direction, to adjust the A/F trim value in the rich direction and reset the MPP ignition trim value;

    means effective, if the MPP value is too low for the allowable MPP range and the MPP ignition trim value is not at the MPP ignition trim value limit in the advance direction, to adjust the MPP ignition trim value in the advance direction;

    means effective, if the MPP value is too high for the allowable MPP range, to adjust the A/F trim value in the lean direction and reset the MPP ignition trim value;

    means for determining the combustible charge mixture for each combustion chamber from the base value thereof and the A/F trim value for the sensed predetermined engine operating parameters;

    means for determining the ignition timing for each combustion chamber from the base value thereof and the LPP and MPP ignition trim values for the sensed predetermined engine operating parameters.

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