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On-board fuel vapor recovery system having improved canister purging

  • US 5,237,980 A
  • Filed: 12/02/1992
  • Issued: 08/24/1993
  • Est. Priority Date: 12/02/1992
  • Status: Expired due to Fees
First Claim
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1. An on-board fuel vapor recovery system for a fuel system of an internal combustion engine of an automotive vehicle comprising a canister in which volatile fuel vapors are collected, a canister purge solenoid (CPS) valve comprising an inlet port, an outlet port, a valve member controlling flow between said inlet port and said outlet port, resilient bias means resiliently biasing said valve member to close the CPS valve to flow between said inlet port and said outlet port, and a solenoid for operating said valve member, means placing said inlet port in communication with said canister, means placing said outlet port in communication with an intake manifold of the internal combustion engine, means placing said solenoid under the control of an electrical control system that controls the purging of said canister to said intake manifold, said CPS valve'"'"'s solenoid comprising a relatively magnetically permeable stator, said valve member comprising a relatively magnetically permeable armature, said stator and said armature being disposed to have confronting faces defining an air gap across which said stator exerts magnetic attraction force on said armature for operating said valve member against opposite force of said resilient bias means to open the CPS valve to flow between said inlet port and said outlet port when said solenoid is energized by electric current from said electrical control system, the intensity of the magnetic force and hence the extent to which said valve member opens the CPS valve to flow between said inlet port and said outlet port being related to the intensity of the electric current from said electrical control system, characterized in that said stator and said armature are disposed within a relatively magnetically impermeable tube, in that said confronting faces of said stator and said armature are shaped to congruently complement each other with one comprising an intrusion that is congruently complements a protrusion on the other, and in that said resilient bias means is disposed other than between said confronting faces.

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