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Apparatus and method for detecting failure of exhaust gas sensor

  • US 6,920,751 B2
  • Filed: 05/14/2003
  • Issued: 07/26/2005
  • Est. Priority Date: 05/16/2002
  • Status: Expired due to Fees
First Claim
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1. An apparatus for detecting a failure of an exhaust gas sensor disposed downstream of a catalyst converter in an exhaust manifold of an engine, the apparatus comprising a control unit configured to:

  • select from outputs of the exhaust gas sensor a first output having a local maximum amplitude value;

    select from outputs of an air-fuel sensor a second output having a local maximum amplitude value, the air fuel ratio sensor disposed upstream of the catalyst converter;

    determine a ratio between the local maximum amplitude value of the first output and the local maximum amplitude value of the second output; and

    detect the failure of the exhaust gas sensor based on the ratio.

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