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Method and apparatus for detecting abnormalities in fuel systems

  • US 6,557,401 B2
  • Filed: 04/11/2001
  • Issued: 05/06/2003
  • Est. Priority Date: 04/11/2000
  • Status: Expired due to Term
First Claim
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1. A method for detecting an abnormality in a fuel vapor purge system, which has a line that connects an intake passage of an engine to a fuel reservoir and a canister inlet valve, wherein the canister inlet valve is located between the fuel reservoir and a canister to be selectively opened and closed by interlocking with a fuel lid, wherein the method comprises:

  • measuring pressure in the fuel reservoir that is sealed by closing the canister inlet valve after the engine is started when cold or before the engine is started;

    comparing an absolute value of a difference between the pressure in the fuel reservoir and the atmospheric pressure with a predetermined reference value;

    judging whether or not the fuel reservoir has an abnormality from the comparison; and

    performing an abnormality detection procedure for the fuel vapor purge system with negative pressure applied from the intake passage to the line of the fuel vapor purge system if it is determined that the fuel reservoir has an abnormality.

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