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Method and arrangement for checking the aging condition of a catalyzer

  • US 5,267,439 A
  • Filed: 12/13/1991
  • Issued: 12/07/1993
  • Est. Priority Date: 12/13/1990
  • Status: Expired due to Fees
First Claim
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1. A method for checking the state of deterioration of a catalytic converter by utilizing a lambda probe arranged rearward of the catalytic converter, the method comprising the steps of:

  • monitoring the output signal of said lambda probe during a transition taking place within a pregiven time span from a lean mixture composition, which is indicated by a low-level of said output signal, to a rich mixture composition, which is indicated by a high-level of said output signal;

    checking said output signal while passing from said low-level to said high-level to determine if an overshoot occurs in the form of an excessive jump in said output signal which departs for a short time from the expected trace of said output signal;

    determining if the amplitude of said overshoot exceeds a pregiven threshold amplitude; and

    ,determining the state of deterioration of said catalytic converter from the occurrence of said overshoot having an amplitude exceeding said threshold amplitude.

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