MXPA99002659A - Welded construction for fuel vapor purge regulator valve assembly - Google Patents

Abstract

An electrically controlled fuel vapor canister purge pressure regulator valve assembly has the regulator valve housing formed integrally with the solenoid operated valve body. A pressure responsive diaphragm is disposed in the housing to form on opposite sides thereof, an inlet chamber and an outlet chamber. The valve body has an inlet passage communicating with the inlet chamber and an outlet passage communicating with the outlet passage. The solenoid controls by-pass flow around the diaphragm to the outlet chamber. The outlet passage is closed by a closure member defining an outlet passage and valve seat. The diaphragm has a plate thereon moveable with the diaphragm to control flow over the valve seat. The outlet closure member encloses the diaphragm periphery and is sealed to the housing by a weld ring which may be spin friction or ultrasonically welded to the housing. An inlet chamber closure member forms an inlet fitting and inlet passage and retains a filter in the inlet chamber . The inlet closure member is sealed to the housing by a weld ring similar to the outlet closure member.

Description

SOLDED CONSTRUCTION FOR FUEL STEAM PURGE REGULATOR VALVE ASSEMBLY BACKGROUND OF THE INVENTION The present invention relates to devices for controlling the introduction of steam from the fuel tank into the air inlet of an internal combustion engine, to prevent the escape of vapors from the fuel tank into the atmosphere. Recently legislated regulations for the amount of fuel vapor emissions allowable from unburned fuel have required the complete shutdown of engine fuel supply systems that use volatile fuel. In particular, legislated regulations to control the emission of unburned motor fuel in motor vehicles have required that fuel vapor be stored and contained during periods of non-operation of the engine, and that the storage vessel be purged during engine operation. In typical motor vehicle systems, a can filled with carbon adsorbs the fuel vapors during periods of non-operation of the engine, and the can is purged allowing fuel vapors from the can to enter the engine air intake or to the intake manifold during engine operation.

However, it is necessary to control the flow of this stored fuel vapor towards the intake manifold of the engine, in order to prevent excessively rich combustion in the engine, which in turn, would produce unacceptable emissions of engine combustion products. or a failed operation of the engine and its arrest. Currently, motor vehicles, particularly light trucks and passenger vehicles, employ electrically operated fuel injectors, which are controlled by an electronic control unit (ECU) that receives signals from sensors that measure the operating parameters of the engine, including the chemical composition of the engine exhaust. Accordingly, it has been desired to incorporate a control of the fuel vapor purge with the electronic control of the engine by means of the electronic control unit. In the first fuel vapor purge systems, a solenoid operated valve controlled atmospheric bleeding to a vacuum signal from the engine intake manifold, to provide a reference pressure for a pressure regulating valve. This technique has the drawback of creating a flow of atmospheric ventilation to the intake manifold and a loss of vacuum in the manifold. More recently, it has been proposed to control the flow from the steam can to the intake manifold of the engine, by means of a pressure regulator with a solenoid operated valve that controls the flow of steam from the can to the regulator inlet. pressure in response to a control signal from the electronic control unit. This device and this control technique are shown and described in the pending United States patent application of Daniel DeLand and Charles Detweiler, entitled "Fuel Vapor Purge Control", serial number 07 / 949,106, filed on October 10, 1997, and assigned to the assignee of the present invention. The latter device uses an elastomeric diaphragm to operate the pressure regulating valve, and has the solenoid operated valve attached to the regulator body, and the solenoid operated valve has a gate to control the flow around the diaphragm. Normally, pressure regulating valves operated by diaphragm are constructed in a manner to have the periphery of the diaphragm exposed to the atmosphere. In these constructions, when the diaphragm is formed of materials suitable for the extremes of temperature found in the service of the vehicle, problems have been encountered with the migration of fuel vapor to the banks, and evaporation into the atmosphere. In addition, the fuel vapor purge control valve assemblies of the aforementioned type, have required a separate in-line filter between the regulator valve assembly and the fuel can, to prevent carbon particles from the can and other foreign matter enter the throttle valve and cause valve malfunction, such as contamination of the valve seat. In accordance with the foregoing, it has been desired to provide a fuel vapor purge control valve that regulates the pressure, electrically controlled, that is sealed sufficiently to prevent migration and escape of fuel vapor into the atmosphere, through the diaphragm, that is resistant to the entry and trapping of foreign particles, that is easy to assemble and calibrate, reliable in a prolonged service, and that is of low manufacturing costs. SUMMARY OF THE INVENTION The present invention provides a solution to the problem described above, by means of a unique design and construction for the accommodation of the regulating valve, wherein the housing of a fuel vapor canister purge valve assembly for the diaphragm of the The regulator is preferably formed integrally with the body for the bypass valve of the solenoid-operated diaphragm. The diaphragm is sealed in a recess in the throttle valve housing by a cover that forms the outlet gate and the seat for the pressure regulating valve; and the lid is sealed to the body by welding a ring, thus completely enclosing the diaphragm. The inlet side of the pressure regulating valve is closed by a cover having a vapor inlet connection formed integrally thereon, and in the same manner sealed to the regulator housing on a filter by welding a ring. In one embodiment, the welding is performed ultrasonically; and in an alternative manner, the welding is performed by friction by centrifugal welding of the ring on the periphery of the housing and the cover. The present invention, therefore, provides a very simple construction for housing the pressure regulator of a fuel vapor purge valve assembly, and has the valve body operated by solenoid integrally formed therewith, and the housing sealed on opposite sides of the diaphragm by lids that have the connector connections integral with it and sealed by welding a ring. BRIEF DESCRIPTION OF THE DRAWING The single figure of the drawing comprises a cross section through the plane of symmetry of the valve assembly of the present invention, and is a pictorial representation of the valve employed in a fuel vapor purge system for a vehicle of motor. Detailed Description of the Invention Referring to the drawing, the valve assembly of the present invention is generally indicated at 10, and has a pressure regulating valve indicated generally at 12, and a solenoid operated valve indicated generally at 14 attached thereto. , operating the set of 10 to control the flow between a fuel vapor can 16 and an intake manifold of the engine 18. The valve operated by solenoid 14 is intended to be controlled by an electronic control unit (ECU), such as the type used in a motor vehicle to control the operation of the engine fuel injectors. The pressure regulating valve assembly 18 has a cover or housing 22 having a generally hollow cylindrical configuration with the body 24 of the solenoid valve 14 preferably integrally formed therewith as a single piece, and defining an inlet passageway. for the valve 14, and an outlet passage 28 communicating with the interior of the housing 22. The passages 26, 28 in the valve body 24 communicate with a hole 30 formed on the body of the valve 24. The hole 30 has an annular member 32 disposed therein axially intermediate the passages 26, 28; and the member 32 defines thereon a valve seat 34, on which sits a preferably spherical valve member 36. The valve 14 includes a coil 38 on which is wound a coil 40 of an electrically conductive material, such like magnetic wire. The coil 40 has its ends terminating each one on an electrical connector terminal, one of which is illustrated and denoted by the reference numeral 42, and which extends to a receptacle cover portion 44 formed in the body 24. The electrical terminals, such as the terminal 42, in a typical can purge system, are connected to the electronic control unit 20. The coil 38 has centrally disposed therein a non-magnetic armature guide member 46, which has its lower end of a reduced diameter, as denoted by the reference numeral 48, to be recorded on the inner periphery of a ferromagnetic flow ring 50. The ring 50 has a shoulder 53 formed thereon, which is recorded in an aperture. 52 formed in a ferromagnetic pole frame generally in the form of C 54, which passes around coil 40. The upper flange of coil frame 54 has an opening 56 formed therein, through s from which a piece of ferromagnetic pole or flow manifold 58 is received, which is recorded against the armature guide 46, and is piloted therein by a reduced diameter portion 60. A ferromagnetic armature member 64 is slidably received. in the guide member 46, with its lower end registered against the valve member 36. The upper end of the frame 64 has the lower end of a spring 62 registered against it; and the upper end of the spring 62 is registered against the lower surface of an adjusting pin 66 threadably engaged in the pole piece 58, to adjust the preload of the spring 62 on the armature 64, to produce the desired flow for a given current in the spool 40. Once the preload on the spring has been adjusted by rotation of the pin 66, the upper end of the body is sealed by a cover 68 secured thereto in any convenient manner, for example, by welding. In operation, upon receipt of an electrical signal from the electronic control unit, the current flow in the coil 40 creates magnetic forces on the armature 64, causing the armature to rise against the force of the spring 62, to allow the opening of the armature. valve member 36 on the seat 34, in order to allow flow between the passage 26 and the passage 28 in the valve body. The housing of the regulator 22 has a partition or wall 70 formed therethrough, forming a first cavity or chamber 72, communicating with the passage 26. The opposite side of the wall 70 forms a second chamber 74, which communicates with the passage 28. A bleed hole 76 is formed through the wall 70, to allow the cushioned flow therethrough, to equalize the pressure on the opposite sides of the wall 70. A layer of filter material is provided suitable porous 78 in the housing 22, and is registered on an annular shoulder 80 formed around it, and secured thereon by a cover or closure 82. The closure 82 has an inlet connection 84 formed thereon, with a passage 86 through it communicates with the chamber 72. The connection 86, in a typical fuel steam can purge system, is connected to the steam can 16. The lower periphery of the cylindrical wall of the housing 22, and a portion d Corresponding cylindrical wall 88 of the cover 82, have a ring 90 received thereon, which is commonly secured thereto for sealing therebetween by welding. In one embodiment, the welding can be performed ultrasonically, and alternatively in another embodiment it can be performed by friction, by rotating the ring 90 with respect to the housing 22. A second annular shoulder 92 is formed in the cylindrical wall of the housing 22, in the upper surface of the wall 70, and receives thereon, in a narrow fitting configuration, for periphery of a flexible elastomeric diaphragm 94, which has its periphery retained and compressed by the cylindrical wall portion 96 of a cover 98. The cover 98 has an inlet connection 100 formed externally thereon, and an annular valve seat 102 formed on its bottom surface, and extending to the chamber 74, whose valve seat communicates with a passage 104 formed through the connection 100.

The diaphragm 94 has a movable valve member or plate 106 provided on its upper surface, and disposed thereon for relative movement with respect to the valve seat 102. The valve member 106 is forced downwardly by the lower end of a valve member. spring 108 registered against the plate 106, with the upper end of the spring 108 registered against the lower surface of the cover 98. The cylindrical wall 96 of the cover 98 has a gate 99 formed therein, which is oriented to coincide with, and communicating with, the valve outlet passage 28, to allow flow into the chamber 74. The cylindrical wall 96 of the cover 98 closely matches the inner periphery of the upper portion of the cylindrical wall of the housing 22, and is retained therein by a ring 110, which is sealed thereon by welding, such as ultrasonic welding or centrifugal, to seal the chamber 74. It will be understood that, during welding, the ring 110 is limited by external elements (not shown) to apply a downward load on the cylindrical wall 96 of the cover 98, in order to compress the outer periphery of the diaphragm 94 on the shoulder 92, and seal the diaphragm in the regulator housing. In the operation, in the non-energized state, with the engine inoperative, the valve 14 is forced to close by the spring 62, preventing the fuel vapor from the can 16 from entering the passage 28 and the chamber 74. When starting the engine , the electronic control unit opens the valve 14 by a desired amount, to allow flow to the chamber 74; and the differential pressure between the chambers 72 and 74 acts on the diaphragm 94 to move the valve member 106 against the force of the spring 108, in order to maintain a desired pressure in the chamber 74. The valve 14 is electrically controlled by the electronic control unit, to maintain the desired amount of flow to the chamber 74. In presently preferred practice, the coil assembly, the C-frame, the flow manifold, and the pole piece, together with the electrical terminals, they can be inserted as a mold insert, and can be encapsulated with molded material in one operation, to form the valve body 24 and the pressure regulator housing 22. The valve assembly of the present invention includes a self-contained filter integrated that protects the valve operated by solenoid 14 and the pressure regulating valve 12 of the foreign particles. The valve assembly of the present invention, therefore, provides simplicity of construction and assembly, with a minimum of parts, and provides a complete seal around the periphery of the diaphragm, to prevent the migration of vapors therethrough, and the escapes into the atmosphere. The valve of the assembly of the present invention, therefore, is simple to assemble, reliable service, and low manufacturing costs. Although the invention has been described so far with respect to the illustrated embodiments, it will be understood that the invention can be modified and varied, and is limited only by the following claims.

Claims (9)

1. CLAIMS 1. A fuel vapor box purge regulator assembly, comprising: (a) housing means having an inlet adapted for connection to a fuel vapor box and an outlet adapted for connection to an air inlet of motor induction; said housing means having a first fluid pressure chamber communicating with said outlet and a second fluid pressure chamber communicating with said inlet and pressure responsive means capable of moving in response to the pressure differential between said first and second fluid pressure chambers; (b) a pressure regulating valve arranged for movement by said member that responds to the pressure to control the pressure in said outlet; (c) electrically operated valve means having an inlet connected by gate to said second fluid pressure chamber and an outlet connected by gate to said first fluid pressure chamber, said valve means being capable of operating to control the flow of said second to said first chamber; and (d) said housing means includes a first housing bushing member defining a body for said valve means, a second housing bushing member defining said outlet and arranged to seal said means responsive to said pressure. first bushing member, wherein said first and second housing bushing members are sealed by welding.
2. 2. The assembly defined in claim 1, wherein said pressure responsive means comprises a flexible diaphragm.
3. The assembly defined in claim 1, wherein said electrically operated means includes a body integrally formed with said housing means.
4. 4. The assembly defined in claim 1, wherein said valve means are electromagnetically actuated.
5. The assembly defined in claim 1, wherein said housing means includes a third bushing member defining said inlet, wherein said third bushing member is sealed to said first bushing member by welding.
6. 6. A method of making a fuel vapor purge regulator assembly, comprising: (a) forming a first housing bushing defining an exit; (b) forming a second housing bushing defining a steam inlet and a body with an inlet gate and an outlet gate for an electrically operated valve; (c) arranging a diaphragm that responds to the pressure in said second bushing and forming a fluid pressure chamber therewith; (d) arranging said first bushing on said diaphragm and sealing said diaphragm; (e) welding said first bushing to said second bushing and sealing said pressure chamber; and (f) disposing an electrically operated valve in said body and controlling the flow from said steam inlet to said fluid chamber. The method defined in claim 6, wherein said welding step includes arranging a ring on the periphery of said first and second ferrules and welding said annulus to the periphery of said first and second ferrules. The method defined in claim 6, wherein said welding includes ultrasonic welding. The method defined in claim 6, wherein said solder includes spin casting.