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Method for controlling the level of oxygen stored by a catalyst within a catalytic converter

  • US 5,842,340 A
  • Filed: 02/26/1997
  • Issued: 12/01/1998
  • Est. Priority Date: 02/26/1997
  • Status: Expired due to Term
First Claim
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1. A method for controlling the oxygen storage level of a catalyst within a catalytic converter coupled to an engine comprising the steps of:

  • obtaining an expression for the mass of oxygen flowing into the catalytic converter,wherein the expression includes the term (λ

    inlet -1)/λ

    inlet where λ

    inlet is equal to a normalized air/fuel ratio;

    applying a rate modifier to the expression to obtain an oxygen storage rate to continuously calculate the oxygen storage level of the catalyst;

    comparing the oxygen storage level to a predetermined threshold value, which provides positive and negative oxygen deviation values; and

    responding to a positive oxygen deviation value by decreasing an air/fuel ratio into the engine, andresponding to a negative oxygen deviation value by increasing the air/fuel ratio into the engine.

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