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Method for monitoring the performance of a catalytic converter

  • US 5,842,339 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 monitoring the performance of a catalytic converter comprising the steps of:

  • providing a value for a mass flow rate selected from one of a mass flow rate of air and a mass flow rate of fuel in an exhaust gas stream entering the catalytic converter;

    providing a value for a first normalized air-fuel ratio;

    calculating an amount of oxygen stored in the catalytic converter using one of the mass flow rate of air and the mass flow rate of fuel together with the first normalized air-fuel ratio,wherein a numerical integration is performed using integration limits determined from dynamic voltage signals, andwherein a pumping delay from an engine and a transport delay within an exhaust system coupling the engine to the catalytic converter is used in determining the amount of oxygen stored in the catalytic converter; and

    comparing the amount of oxygen stored in the catalytic converter with pass-fail criteria to determine the performance of the catalytic converter.

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