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Malfunction test apparatus for fuel vapor purge system

  • US 6,405,718 B1
  • Filed: 07/11/2000
  • Issued: 06/18/2002
  • Est. Priority Date: 07/30/1999
  • Status: Expired due to Fees
First Claim
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1. A malfunction test apparatus for a fuel vapor purge system, comprising:

  • a purge system, wherein the purge system connects a fuel tank with a canister and collects fuel vapor generated in the fuel tank in the canister, wherein the purge system purges the collected fuel vapor to an intake passage of an internal combustion engine through a purge passage, the purge passage including the fuel tank; and

    testing means, wherein the testing means seals the purge passage and measures a change of pressure due to fuel vapor generation in the fuel tank, wherein the testing means measures a rate of change of the pressure in the purge passage after differentiating the pressure in the purge passage from the pressure outside the purge passage and after sealing the purge passage, and wherein the testing means determines whether there is a leak in the purge passage based on the change of pressure due to fuel vapor generation and on the measured rate of change of the pressure in the purge passage, wherein, after measuring the change of pressure due to fuel vapor generation, the testing means determines that there is a leak in the purge passage only if the change of pressure due to fuel vapor generation satisfies a predetermined condition.

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