Purge valve for on board fuel vapor recovery systems

• US 4,944,276 A
• Filed: 06/22/1988
• Issued: 07/31/1990
• Est. Priority Date: 10/06/1987
• Status: Expired due to Fees

• Current Assignee: Borg-Warner Automotive Incorporated (BorgWarner Incorporated)
• Original Assignee: Colt Industries Incorporated
• Inventors: McAuliffe, Lawrence Jr., House, William J., Kline, Loren H.
• Primary Examiner(s): CHAMBERS, A MICHAEL
• Application Number:
  US07/209,511
• Time in Patent Office: 769 Days
• Field of Search: 123/520, 123/525, 123/1 A, 137/614.21, 251/129.05, 251/129.15, 251/129.2
• US Class Current: 123/520
• CPC Class Codes: F02M 2025/0845 Electromagnetic valves
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: Y10T 137/88062 Coaxial oppositely directed seats

Abstract

A purge valve for a vehicle mounted fuel vapor recovery system is made up of a main housing and two end caps which snap fit together to seal and mount a computer controlled solenoid valve and a diaphragm controlled regulating valve. The housing is designed so that the required valve seats are integrally molded in the housing as are the various internal passages and chambers. A compression post formed on one end cap seats the solenoid assembly firmly against an abutment surface on the housing.

Claims

1. A purge valve for controlling the flow of vapor from a vapor source to a vacuum source, said valve comprising an elongate generally tubular main housing having a first chamber opening at one axial end of said housing and a second chamber opening at the opposite axial end of said housing, means defining an inlet passage adapted to be connected to a vapor source extending into said housing and an outlet passage adapted to be connected to a vacuum source extending into said housing, means defining a first axial passage extending from said inlet passage to an opening at the inner end of said first chamber, means defining a second axial passage extending from an outlet opening in said second chamber to said outlet passage, means defining a third passage placing said first and second chambers in constant communication with each other, first and second end cap means sealingly mounted at the opposite ends of said main housing to respectively seal said first and second chambers from atmopshere, first solenoid controlled valve means in said housing operable to selectively block or accommodate flow from said first axial passage into said first chamber, and second pressure responsive valve means operable to selectively block or accommodate flow from said second chamber into said second axial passage in response to variations in pressure in said outlet passage.

2. The invention defined in claim 1 further comprising means on said housing defining first and second annular valve seats integrally formed on said housing and respectively projecting axially into each of said first and second chambers coaxially of said first and said second axial passages, said first valve means including a valve head movable into and out of engagement with said first valve seat, and said second valve means including a flexible diaphragm having a central portion movable to and from sealing engagement with said second valve seat in response to variations in pressure in said outlet passage.

3. The ivention defined in claim 2 wherein said diaphragm is clampingly sealed around its outer periphery between said second end cap and said opposite end of said housing, said diaphragm defining a flexible wall common to said second chamber and a third chamber in said end cap vented to atmosphere, and spring means biassing said diaphragm away from said second valve seat.

4. The invention defined in claim 1 wherein said first chamber include a relatively large diameter outer section extending axially inwardly from said one end of said housing and a coaxial relatively small diameter inner section extending inwardly from an annular radial shoulder on said housing at the inner end of said outer section, said solenoid controlled valve means comprising a cylindrical solenoid assembly received within said outer section of said first chamber and having one end seated on said radial shoulder, and an axially compressible port mounted on said first end cap compressively engaged between said first end cap and the opposite end of said solenoid assembly to axially press said assembly against said radial shoulder.

5. A purge valve for controlling the flow of vapor from a vapor source to a vacuum source, said valve comprising a one piece molded vertically elongate main housing having a first bore extending upwardly into said housing from its lower end to a horizontal downwardly facing shoulder, a second bore coaxial with and of a diameter less than said first bore extending upwardly into said housing from said shoulder to an upper end, and a third bore coaxial with and of a diameter less than said second bore extending upwardly into said housing from said upper end of said second bore, means defining an inlet passage adapted to be connected to said vapor source and intersecting said third bore, a downwardly facing annular valve seat on the upper end of said second bore coaxial with said third bore, a generally cylindrical solenoid assembly received within said first bore and having one end engaged with said shoulder, said solenoid assembly including a coil and an armature projecting coaxially upwardly from said one end of said assembly, a valve head on the upper end of said armature, an end cap mounted on the lower end of said housing sealingly closing the lower end of said first bore, integral compression means on said end cap compressively engaged with the lower end of said solenoid assembly pressing said assembly upwardly against said shoulder, spring means in said solenoid assembly biassing said armature upwardly to sealingly engage said valve head with said valve seat to block fluid communication between said second and third bores, electrical connector means in said end cap for connecting said coil to an electric power source, said coil being operable when energized to withdraw said armature downwardly to disengage said valve head from said valve seat to accommodate fluid flow from said third bore into said second bore, means on said housing defining an outlet passage adapted to be connected to a vacuum source, and second valve means in said housing for controlling flow of fluid from said third bore into said outlet passage in accordance with pressure variations in said outlet passage.

6. The invention defined in claim 5 further comprising a plurality of integral upwardly facing shoulders on the exterior of said housing adjacent said lower end, and a plurality of upwardly projecting fingers on said end cap having downwardly facing abutment surfaces adapted to engage said upwardly facing shoulders to retain said end cap on said housing.

7. The invention defined in claim 5 wherein said second valve means comprises means defining an annular recess extending downwardly into said housing from its upper end and communicating with said second bore, an upwardly facing number valve seat on said housing coaxially disposed within said annular recess, said outlet passage opening into said annular recess through said valve seat, a flexible diaphragm sealed around its outer periphery to said housing to close the upper end of said recess, the upper side of said diaphragm being exposed to atmospheric pressure, valve head means on said diaphragm movable upon downward flexing of said diaphragm into sealing engagement with said upwardly facing valve seal to block communication between said annular recess and said outlet passage, and spring means biassing said diaphragm upwardly away from said upwardly facing valve seat.

8. In a vehicle driven by an internal combustion engine, the combination of plurality of fuel system-related components including fuel induction means for the engine, a plurality of separate means each sensing and generating an output signal representative of the instantaneous value of an engine operating parameter, an on-board computer receiving one or more of said sensor output signals and controlling certain engine functions in accordance with certain of said parameters, a fuel storage tank, a fuel vapor canister for storing therein fuel vapors from said tank and purge means for subsequently purging said vapors from said canister to said fuel induction means at a controlled rate for combustion in said engine, said purge means comprising a valve housing having a vapor inlet connected to said canister, a vapor outlet connected to said fuel induction means, and vapor flow passage means extending through said housing from said inlet into an internal chamber and from said chamber to said outlet, first normally closed solenoid actuated valve means in flow passage means between said inlet and said chamber operable upon actuation of its solenoid to accommodate flow of vapor from said inlet into said chamber, and second normally open pressure differential responsive valve means in said flow passage means moveable to a closed position in response to a predetermined reduction in a pressure applied to said outlet by said induction means for controlling the rate of flow of vapor from said chamber into said outlet.

9. The combination of claim 8, wherein said first valve means includes a duty cycle solenoid valve controlled by said computer.

10. The combination of claim 9, wherein said second valve means comprises an engine manifold vacuum responsive diaphragm assembly for limiting the supply of engine manifold vacuum to said chamber so as to establish a desired maximum vapor flow rate to said induction means independently of the opening of said first valve as controlled by said computer.