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Exhaust gas recirculation fault detection system

  • US 6,164,270 A
  • Filed: 08/09/1999
  • Issued: 12/26/2000
  • Est. Priority Date: 08/09/1999
  • Status: Expired due to Term
First Claim
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1. A method of monitoring the integrity of an EGR system of an automotive engine, having an EGR valve and an EGR line for conducting exhaust gas to and from said EGR valve, comprising the steps of:

  • measuring gas pressure in said EGR line at said location downstream of the EGR valve, with the EGR valve being in an open position;

    measuring a gas pressure in an EGR duct at a location downstream of an EGR valve, with the EGR valve being in a closed position;

    determining the gas pressure difference between the gas pressure measured with the EGR valve open and the gas pressure measured with the EGR valve closed; and

    in the event that the gas pressure difference is either less than a first threshold value or greater than a second threshold value, or in the further event that the gas pressure measured with the EGR valve closed is greater than a third threshold value, setting a flag indicating that operation of the EGR system is impaired.

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