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Oxygen-sensor abnormality detecting device for internal combustion engine

  • US 5,331,808 A
  • Filed: 04/14/1993
  • Issued: 07/26/1994
  • Est. Priority Date: 04/16/1992
  • Status: Expired due to Term
First Claim
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1. A device for detecting abnormalities in an air-fuel ratio sensor for use in internal combustion engines, comprising:

  • a catalytic converter installed in an exhaust system of an internal combustion engine;

    air-fuel ratio sensors, installed on upstream and downstream sides of said catalytic converter, for detecting the air-fuel ratio;

    first and second heaters for activating the upstream-side and downstream side air-fuel ratio sensors, respectively;

    means for identifying activity state of said catalytic converter;

    means for identifying activity state of said air-fuel ratio sensors;

    means for controlling heat generation of said heaters; and

    means for detecting abnormalities of one of said air-fuel ratio sensors by comparing outputs of said air-fuel ratio sensors when said catalytic converter is identified to be in inactive state and when said air-fuel ratio sensors are identified to be in active state.

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