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Method and apparatus for maintaining catalyst efficiency of a NO.sub.x trap

  • US 5,832,722 A
  • Filed: 03/31/1997
  • Issued: 11/10/1998
  • Est. Priority Date: 03/31/1997
  • Status: Expired due to Term
First Claim
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1. A method of estimating the amount of SOx accumulated in a NOx trap located in an exhaust passage of an engine comprising a sequence of the steps of:

  • determining an amount of SOx accumulated per unit fuel flow, based on present A/F and present temperature of said trap;

    calculating the rate of SOx accumulation based on said determined amount of SOx and the flow rate of fuel supplied to said engine; and

    calculating the amount of S0x accumulation based on said calculated rate of SOx accumulation and the elapsed time since a previous calculation.

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