EP0998629B1 - Electrovanne lineaire a purge regulee - Google Patents

Electrovanne lineaire a purge regulee Download PDF

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Publication number
EP0998629B1
EP0998629B1 EP98931868A EP98931868A EP0998629B1 EP 0998629 B1 EP0998629 B1 EP 0998629B1 EP 98931868 A EP98931868 A EP 98931868A EP 98931868 A EP98931868 A EP 98931868A EP 0998629 B1 EP0998629 B1 EP 0998629B1
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EP
European Patent Office
Prior art keywords
valve
pressure
valve according
disk
chamber space
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EP98931868A
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German (de)
English (en)
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EP0998629A1 (fr
Inventor
John E. Cook
Murray F. Busato
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Continental Tire Canada Inc
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Siemens VDO Automotive Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • F02M25/0836—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

Definitions

  • This invention relates generally to emission control valves for automotive vehicles.
  • the invention relates to solenoid-operated fluid valves for purging volatile fuel vapors from fuel tanks and vapor storage canisters to internal combustion engines that power such vehicles.
  • a known on-board evaporative emission control system comprises a vapor collection canister that collects volatile fuel vapors generated in the headspace of the fuel tank by the volatilization of liquid fuel in the tank and a canister purge solenoid (CPS) valve for periodically purging collected vapors to an intake manifold of the engine.
  • the CPS valve comprises a solenoid actuator that is under the control of a microprocessor-based engine management system.
  • evaporative emission space that is cooperatively defined by the tank headspace and the canister is purged to the engine intake manifold through the CPS valve, which is fluid-connected between the canister and the engine intake manifold.
  • the CPS valve is opened by a signal from the engine management computer in an amount that allows intake manifold vacuum to draw volatile fuel vapors from the canister for entrainment with the combustible mixture passing into the engine's combustion chamber space at a rate consistent with engine operation to provide both acceptable vehicle driveability and an acceptable level of exhaust emissions.
  • a known CPS valve comprises a movable valve element that is resiliently biased by a compression spring against a valve seat to close the valve to flow when no electric current is being delivered to the solenoid.
  • increasing electromagnetic force acts in a sense tending to unseat the valve element and thereby open the valve to fluid flow.
  • This electromagnetic force must overcome various forces acting on the mechanical mechanism before the valve element can begin to unseat, including overcoming both whatever static friction (stiction) is present between the valve element and the seat, as well as the opposing spring bias force.
  • the valve element/valve seat geometry also plays a role in defining the functional relationship of fluid flow rate through the valve to electric current supplied to the solenoid coil. Furthermore, the extent to which a given valve possesses hysteresis will also be reflected in the functional relationship.
  • each graph plot of fluid flow rate through the valve vs electric current supplied to the solenoid coil may be considered to comprise distinct spans a short initial span that occurs between valve closed position and a certain minimum valve opening; and a more extensive subsequent span that occurs beyond a certain minimum valve opening.
  • CPS valve comprises a linear solenoid and a linear compression spring that is increasingly compressed as the valve increasingly opens. It is sometimes referred to as a linear solenoid purge valve, or LSPV for short.
  • LSPV linear solenoid purge valve
  • Such a valve can provide certain desirable characteristics for flow control.
  • a linear solenoid possesses a force vs. electric current characteristic that is basically linear over a certain range of current.
  • an electromechanical device such as a valve
  • the overall electromechanical mechanism possesses an output vs. electric current characteristic that is a function of not just the solenoid, but also the mechanical mechanism, such as a valve mechanism, to which the solenoid force is applied
  • the output vs. electric current characteristic of the overall device is somewhat modified from that of the linear solenoid alone.
  • each graph plot of fluid flow rate through the valve vs. electric current applied to the solenoid coil may be considered to comprise the spans referred to above, namely, a short initial span that occurs between valve closed position and a cenain minimum valve opening, and a more extensive subsequent span that occurs beyond a certain minimum valve opening.
  • a linear solenoid purge valve may be graphically characterized by a series of graph plots of fluid flow rate vs. electric current, each of which is correlated to a particular pressure differential across the valve.
  • Each graph plot may be characterized by the aforementioned short initial span and the more extensive subsequent span
  • one especially desirable attribute is that a substantially constant relationship between incremental change in an electric control current applied to the solenoid and incremental change in fluid flow rate through the valve may be obtained by appropriate design of the valve element/valve scat interface geometry Within the former span, incremental change in fluid flow rate through the valve may however bear a substantially different relationship to incremental change in an electric control current applied to the solenoid.
  • a certain minimum electric current is required before the valve begins to open.
  • a corresponding graph plot of fluid flow rate vs. electric current may be described as comprising a relatively short initial span where a small incremental change in electric current will result in an incremental change in flow that is much different from the incremental change that occurs over an ensuing span where the valve has opened beyond a certain minimum opening and incremental change in flow through the valve bears a substantially constant relationship to incremental change in electric current.
  • Electric current to the solenoid coil of any solenoid-operated device can be delivered in various ways.
  • One known way is by applying a pulse width modulated D.C. voltage across the solenoid coil.
  • consideration may be given to the frequency response characteristic of the combined solenoid and mechanical mechanism operated by the solenoid. If a pulse frequency that is well within the frequency response range of the combined solenoid and mechanism is used, the mechanism will faithfully track the pulse width signal. On the other hand, if a pulse frequency that is well beyond the frequency response range of the combined solenoid and mechanical mechanism is used, the mechanism will be positioned according to the time average of the applied voltage pulses.
  • the latter technique may be preferred over the former because the mechanical mechanism will not reciprocate at the higher frequency pulse width modulated waveform, but rather will assume a position corresponding to the time averaged current flow in the solenoid coil. Under the former technique, the mechanism could, by contrast, experience significant reciprocation as it tracks the lower frequency waveform, and that might create unacceptable characteristics. In the case of a CPS valve, such characteristics may include undesirable pulsations in the purge flow and objectionable noise caused by repeated impacting of the valve element with the valve seat and/or a limit stop that limits maxinium valve travel Such a valve may experience unacceptable variation in the start-to-flow duty cycle.
  • a known mechanical pressure regulator comprises a flow path having an entrance through which fluid flow that has passed through the valve mechanism enters the pressure regulator flow path and an exit from which fluid flow that has entered the pressure regulator flow path exits the pressure regulator flow path.
  • the pressure regulator comprises a pressure regulating mechanism that regulates the pressure at the entrance of the pressure regulator flow path to a pressure that is essentially independent of pressure at the exit of the pressure regulator flow path.
  • the pressure regulating mechanism comprises a fluid-impermeable movable wall that divides an interior space of the pressure regulator into two variable volume chamber spaces. A first of these spaces is communicated to atmosphere so that the pressure therein is maintained at atmospheric pressure. A second of these chamber spaces forms a portion of the flow path that extends between the pressure regulator entrance and the pressure regulator exit.
  • the movable wall carries an element that selectively restricts the flow path such that the pressure in the second chamber space is regulated to a predetermined magnitude that is substantially independent of the pressure at the pressure regulator exit.
  • the vacuum in the first chamber space is regulated relative to atmospheric pressure to a predetermined magnitude that is substantially independent of the magnitude of the intake manifold vacuum that is communicated to the pressure regulator exit.
  • US-A-5 069 188 discloses a pressure regulator as described above which includes an orifice in the movable wall.
  • the size of the orifice is such in relation to the ability of the engine to create and maintain manifold vacuum that flow though the movable wall via the orifice has essentially no effect on the position that will be assumed by the movable wall for any intensity of manifold vacuum within the range of vacuums for which the valve is designed.
  • the presence of the orifice in conjunction with the connection of the first chamber space to atmosphere provides a certain degree of purging at engine idle where the manifold vacuum is high but the actual induction flow into the engine is relatively low.
  • One aspect of the present invention relates to an improvement in how the pressure regulating function is performed.
  • the inlet port of the canister purge valve is communicated through the canister to the fuel tank headspace such that the pressure at the purge valve inlet port is essentially that which exists in the tank vapor headspace. It has been observed that certain conditions may cause the vapor pressure in the tank headspace to depart from atmospheric pressure such that the pressure applied to the purge valve inlet port departs from atmospheric. Because both the intake manifold vacuum that is applied to the purge valve outlet port and the pressure in the first chamber space of the pressure regulator are referenced to atmospheric pressure, a departure of tank headspace pressure from atmospheric pressure may degrade the intended control strategy.
  • One general aspect of the invention relates to a pressure-regulated purge valve that negates effects of departures of tank vapor headspace pressure from atmospheric on intended control strategy. This is accomplished by communicating the first chamber space of the pressure regulator to the tank vapor headspace pressure, either by a devoted communication path directly to the tank headspace or through any path that is in communication with the tank headspace, such as through the canister.
  • an electrically-operated pressure-regulated fluid flow control valve comprising:- a valve body; an inlet at which fluid flow enters the valve body; an outlet at which fluid flow leaves the valve body; a valve mechanism located within the valve body for controlling fluid flow therethrough; and a pressure regulator connected to the valve body, the pressure regulator comprising a body enclosing an interior space, a flow path passing through the body having an entrance connected to the outlet and an exit, and a pressure regulating mechanism for regulating the pressure at the entrance to the flow path; characterised in that the valve mechanism has a frequency response characteristic which renders it incapable of faithfully tracking the fundamental frequency of an electric control signal whose fundamental frequency is greater than a predetermined frequency which, when applied in control of the valve mechanism, positions the valve mechanism to a position corresponding to a most recent time average of the electric control signal free of any significant pulsing of the valve mechanism; and in that the pressure regulating mechanism comprises a fluid impermeable movable wall dividing the interior
  • a further aspect relates to an LSPV, including a pressure regulator, that is believed to provide further improvements in purge flow control accuracy over a substantial range of valve operation and under diverse operating conditions.
  • a still further aspect relates to the provision of certain constructional features in a pressure regulator that, in association with a CPS valve, are believed to provide improved purge flow control accuracy by significantly attenuating the influence of conditions that would otherwise produce degradation of the purge flow control for a given valve opening.
  • Fig. 1 shows an evaporative emission control system 10 of a motor vehicle comprising a vapor collection canister (carbon canister) 12 and a canister purge solenoid (CPS) valve 14 connected in series between a fuel tank 16 and an intake manifold 18 of an internal combustion engine 20 in a known fashion.
  • An engine management computer 22 supplies a valve control signal as an input to a pulse width modulation (PWM) circuit 24 to create a pulse width modulated signal which is amplified by a drive circuit 26 and applied to electric terminals 14et of valve 14.
  • PWM pulse width modulation
  • Valve 14 comprises a housing 28 having an inlet port 14i that is fluid-coupled via a conduit 30 with a purge port 12p of canister 12 and an outlet port 14o that is fluid-coupled via a conduit 32 with intake manifold 18.
  • a conduit 34 communicates a canister tank port 12t to headspace of fuel tank 16.
  • An operating mechanism comprising a solenoid actuator 14sa is disposed within housing 28 for opening and closing an internal passage that extends between ports 14i and 14o.
  • the mechanism includes a bias spring that acts to urge a valve element 14ve closed against a valve seat 14vs for closing the internal passage to flow.
  • Canister 12 is also seen to comprise a vent port 12v via which the evaporative emission space where the fuel vapors are contained is vented to atmosphere. Such venting may be via an atmospheric vent valve (not shown) that is operated closed at certain times, such as during OBDII testing.
  • Fig. 2 depicts a representative control characteristic for valve 14 wherein fluid flow rate through the valve is related to the duty cycle of a pulse width modulated voltage that is applied across terminals 14et.
  • a certain minimum duty cycle about 10% in the example, is required before the valve begins to open.
  • the flow rate bears a generally straight line relationship to duty cycle.
  • a constant D.C. voltage is applied across terminals 14et.
  • the frequency of the pulse waveform that accomplishes this type of operation is relatively low, a representative frequency being within a range from about 5 Hz to about 20 Hz, but possibly as high as about 50 Hz.
  • the mechanism will experience significant reciprocal motion as it follows the pulse waveform.
  • valve is not pressure-regulated, flow rate will also be a function of the pressure differential across the valve ports. Temperature and voltage variations may also influence the relationship.
  • Fig. 3 shows an example of a linear solenoid purge valve 14', certain parts of which correspond to parts of valve 14 already mentioned, and they will be designated by corresponding primed reference numerals.
  • Valve 14' comprises a two-piece body B1, B2 having an inlet port 14i' and an outlet port 14o'.
  • Valve 14' has a longitudinal axis AX
  • body piece B1 comprises a cylindrical side wall 40 that is coaxial with axis AX and that is open at its upper axial end where it is in assembly with body piece B2.
  • Side wall 40 comprises upper and lower side wall portions 40A, 40B joined by a shoulder 42; the former side wall portion is fully cylindrical while the latter is cylindrical except in the region where it is radially intercepted by port 14o'.
  • Port 14i' is in the shape of an elbow that extends from the lower axial end of side wall 40.
  • body piece B 1 is enclosed except for its open upper axial end and the two ports 14o' and 14i'.
  • a linear solenoid S is disposed in body piece B1, having been introduced through the open upper end of body piece B1 during fabrication of the valve.
  • the solenoid comprises a bobbin 44, magnet wire wound on bobbin 44 to form a bobbin-mounted electromagnetic coil 46, and stator structure associated with the bobbin-coil.
  • This stator structure comprises an upper stator end piece 48 disposed at the upper end of the bobbin-mounted coil, a cylindrical side stator piece 50 disposed circumferentially around the outside of the bobbin-mounted coil, and a lower stator end piece 52 disposed at the lower end of the bobbin-mounted coil.
  • Upper stator end piece 48 includes a flat circular disk portion whose outer perimeter fits to the upper end of side piece 50 and that contains a hole into which a bushing 54 is pressed so as to be coaxial with axis AX.
  • the disk portion also contains another hole to allow for upward passage of a pair of bobbin-mounted electrical terminals 56 to which ends of magnet wire 46 are joined.
  • Piece 48 further comprises a cylindrical neck 58 that extends downward from the disk portion a certain distance into a central through-hole in bobbin 44 that is co-axial with axis AX.
  • the inner surface of neck 58 is cylindrical while its outer surface is frusto-conical so as to provide a radial thickness that has a progressively diminishing taper as the neck extends into the bobbin through-hole.
  • Lower stator end piece 52 includes a flat circular disk portion whose outer perimeter fits to the lower end of side piece 50 and that contains a hole into which a bushing 60 is pressed so as to be coaxial with axis AX.
  • Piece 52 further comprises an upper cylindrical neck 62 that extends upwardly from the disk portion a certain distance into the central through-hole in bobbin 44 and that is co-axial with axis AX.
  • Neck 62 has a uniform radial thickness.
  • Piece 52 still further comprises a lower cylindrical neck 64 that extends downward from the disk portion a certain distance so that its lowermost end fits closely within lower side wall portion 40B.
  • a valve seat element 66 is necked to press-fit into the open lower end of neck 64 and is sealed to the inside of wall portion 40B by an O-ring 67. Above the lowermost end that fits to side wall 40, neck 64 contains several through-holes 68 that provide for communication between port 14o' and the space disposed above seat element 66 and bounded by neck 64. Side wall 40 allows this communication by not restricting through-holes 68.
  • Bushings 54 and 60 serve to guide a valve shaft 70 for linear travel motion along axis AX.
  • a central region of shaft 70 is slightly enlarged for press-fit of a tubular armature 72 thereto.
  • the lower end of shaft 70 comprises a valve 74 that coacts with valve seat element 66.
  • Valve 74 comprises a head, integrally formed with shaft 70 and having the general shape of a tapered pintle, comprising a rounded tip 74a, a frustoconical tapered section 74b extending from tip 74a, a grooved cylindrical section 74c extending from section 74b, and an integral back-up flange 74 d that in part defines the upper axial end of the groove of section 74c.
  • An O-ring type seal 76 of suitable fuel-resistant elastomeric material is disposed in the groove of section 74c.
  • Seat element 66 comprises an inwardly directed shoulder 66a that contains a portion of a through-hole that extends axially through the seat element.
  • This portion of the through-hole comprises a straight cylindrical section 78 and a frustoconical seat surface 80 that extends from the upper end of section 78 and is open to the interior space bounded by neck 64.
  • the remainder of the through-hole axially below section 78 is designated by the reference numeral 81.
  • shaft 70 protrudes a distance above bushing 54 and is shaped to provide for attachment of a spring seat 79 thereto.
  • a helical coiled linear compression spring 86 is captured between seat 79 and another spring seat 87 that is received in a suitably shaped pocket of piece B2.
  • a calibration screw 88 is threaded into a hole in the end wall of this pocket coaxial with axis AX, and it is externally accessible by a suitable turning tool (not shown) for setting the extent to which spring seat 87 is positioned axially relative to the pocket.
  • Terminals 56 are also joined with terminals 90 mounted in piece B2 to form an electrical connector 92 for mating engagement with another connector (not shown) that connects to drive circuit 26.
  • a rounded surface portion of seal 76 has circumferentially continuous sealing contact with seat surface 80 so that the valve closes the flow path between ports 14o' and 14i'.
  • the upper portion of armature 72 axially overlaps the air gap that exists between the upper end of neck 62 and the lower end of neck 58, but slight radial clearance exists so that armature 72 does not actually touch the necks, thereby avoiding magnetic shorting.
  • the degree of valve opening depends on the magnitude of electric current flow through the solenoid coil 46 so that the purge flow through the valve is effectively controlled by controlling the electric current flow through the coil. As the magnitude of electric current flow progressively increases from zero, it reaches a value sufficient to break whatever stiction exists between the seated O-ring 76 and seat surface 80. At that point the valve mechanism begins to open against the opposing force of spring 86. Valve opening commences as soon as O-ring seal 76 loses contact with seat surface 80.
  • a representative graph plot of fluid flow rate vs. electric current reveals three distinct spans: a first span where current increases without any valve opening; a second span where the valve begins to open but the tapered section 74b is not yet fully effective to control the flow by itself; and a third span where the valve has opened sufficiently to allow section 74b to alone control the flow.
  • the second span may be characterized by a relationship wherein a small incremental change in average electric current in solenoid S causes an incremental change in fluid flow rate that is substantially different from the incremental change results when the valve operates instead within the third span.
  • Coil 46 of solenoid S is connected across a source of D.C. voltage pulses, such as a pulse-width modulator circuit operating at a selected frequency.
  • Electric current flow to the coil may be controlled by a solid-state driver in accordance with a control output signal from an engine management computer, and the circuit may include a feedback loop for feeding back a signal representative of electric current flow through the solenoid coil so as to endow the control with the ability to compensate for certain environmentally induced changes that could otherwise impair control accuracy.
  • the feedback loop can automatically regulate the current flow through coil 46 such that the influences of changes in ambient conditions, such as temperature and D.C. supply voltage to the circuit, are essentially negated, thereby enabling the valve to operate to a desired position commanded by the circuit substantially free of such influences.
  • Fig. 4 shows a mechanical pressure regulator 200 operatively associated with valve 14'.
  • Pressure regulator 200 comprises a two-piece body 202 having a base 202b and a cover 202c, both of which are fabricated from suitable material, such as fuel tolerant injection molded plastic.
  • Base 202b comprises an inlet port 204 and an outlet port 206 each of which is in the form of a nipple.
  • a conduit 208 fluid connects port 204 with outlet port 14o' of valve 14', and outlet port 206 is fluid connected with engine intake manifold by another conduit that is not specifically illustrated in the Fig.
  • the nipple forming outlet port 206 comprises a radial segment that extends inwardly of body 202 to form an axial segment that is coaxial with an axis 210 of pressure regulator 200. This axial segment terminates as a circular rim forming a seal seat 212.
  • Base 202b further comprises a cylindrical walled cup having a circular annular radial shoulder 214. This cup terminates in a circular rim 216 that is coaxial with axis 210.
  • Cover 202c has a generally circular shape whose outer periphery contains one or more catches 218 that attach the cover to the otherwise open end of the cup of base 202b at rim 216 by snapping over a lip of the rim as shown.
  • the beaded outer circular perimeter of an impermeable flexible member 220 is held captured between the outer margin of cover 202c and rim 216 in a sealed manner.
  • Centered with member 220 coaxial with axis 210 is a rigid circular disk 222.
  • a circular seal element 224 Secured centrally to disk 222 in confrontation to rim 216 is a circular seal element 224.
  • element 224 is secured to disk 222 by being molded onto the disk, with a portion of the molded material passing from the element, through a small hole in the center of the disk, to create an interlocking circular formation 226 on the opposite face of the disk.
  • the outer margin of disk 222 contains an annular area free of molded material.
  • One end of a helical coiled compression spring 228 bears against this annular area.
  • the opposite end of the spring bears against a wall of base 202b that extends circumferentially partially around the axial segment of the outlet port nipple below rim 212.
  • Cover 202c is formed with a central depression 230, and in the condition shown by Fig. 4, spring 228 is seen forcing disk 222 away from rim 212 such that the flat end surface of formation 226 is biased against the flat end surface of depression 230.
  • the assembled parts 220, 222, 224 form a fluid impermeable wall 232 that divides the interior of body 202 into first and second chamber spaces 234, 236.
  • chamber 236 provides free communication between ports 204 and 206.
  • the flow path thus provided is depicted by the unnumbered arrows which represent purge flow from valve 14', through inlet port 202, through chamber space 236, and through outlet port 204 to the engine intake manifold.
  • Chamber space 234 is communicated to the fuel tank vapor headspace via a vapor collection (charcoal) canister 237.
  • Cover 202c comprises a nipple 202n onto which one end of a tubular conduit 238 is fitted in a sealed manner. The opposite end of conduit 238 is fitted in a sealed manner onto a tee 14t that is fashioned with the nipple forming inlet port 14i'.
  • 202n could alternatively be directly communicated to the tank headspace by a devoted conduit, making tee 14t unnecessary.
  • Pressure regulator 200 operates in the following manner. For purposes of explanation, assume that it is in the position illustrated in the Fig., that equal pneumatic pressures exist in the two chamber spaces 234, 236, and that valve 14' is open. The creation of increasing intake manifold vacuum in chamber space 236 will begin to create an increasing pressure differential on wall 232. At a certain differential, the bias force of spring begins to be overcome, and the central region of wall 232 begins moving toward rim 212. Tank headspace pressure is maintained in chamber space 234 because vapor is drawn through canister 237, inlet port 14i', tee 14t, and conduit 238 as wall 232 moves toward rim 212.
  • seal element 224 When the vacuum has increased to a certain larger magnitude, seal element 224 will be sufficiently close to rim 212 to create a restriction of the purge flow. The seal element may actually close on rim 212, albeit only momentarily. Such restriction or closure, tends to reduce the pneumatic pressure differential acting on wall 232 so that spring 228 then tends to move the central region of the wall away from rim 212.
  • Tank vapor pressure in chamber space 234 is maintained as vapors are forced out opposite the direction they flowed in.
  • sealing element 224 will assume an average position that causes the vacuum in chamber space 236 to be regulated to a predetermined magnitude that is substantially independent of the magnitude of intake manifold vacuum and that causes flow through the valve to be essentially independent of change in pressure at the valve inlet. Hence, a substantially constant pressure differential is maintained across valve 14'. Now as valve 14' operates to different positions as commanded by the signal applied to solenoid S, the commanded positions will produce substantially the correspondingly intended purge flow rate, substantially free of variation in intake manifold vacuum and tank headspace pressure. Because flexible member 220 is provided with a convolution, it imposes no restriction of the movement of the central region of the movable wall relative to the open end of the walled axial conduit segment that contains rim 212.
  • the disclosed embodiment when operated at a fundamental pulse waveform frequency substantially greater than the frequency response of the valve mechanism, does not utilize a pressure regulator for the purpose of dampening purge flow pulsations. Rather, the creation of a predetermined pressure differential acting across valve 14' enables a given command signal to directly provide the intended flow rate, free of manifold vacuum variations and tank headspace pressure variations. It is believed that this can eliminate the need for the engine management computer to include a map for processing an input representing intake manifold vacuum and a map for processing an input representing tank headspace pressure when the computer calculates what the command signal to the solenoid coil of the valve should be.
  • Fig. 5 shows a series of representative graph plots of purge flow rate through valve 14' vs. time-averaged D.C. current flow in the solenoid coil.
  • Each graph plot corresponds to a different value of intake manifold vacuum as indicated in Fig. 5, but the important effect of pressure regulator 200 can be seen by the substantial congruence of graph plots for 200, 300, 400, 500, and 600 mm Hg intake manifold vacuum.
  • purge flow commences at about 183 milliamps current for the substantially congruent plots.
  • Figs. 6 and 7 illustrate another embodiment in which an LSPV and a pressure regulator are integrated into a single assembly. Like reference numerals from the preceding Figs. are used to identify like parts, although from comparison it can be seen that certain parts differ in certain details of construction.
  • Figs. 6 and 7 show that pressure regulator 200 has been integrated into the lower end of LSPV 14'. The nipples that formed valve outlet port 14o' and regulator inlet port 208 have been eliminated. The portion of the flow path downstream of the valve pintle is communicated to chamber space 236 directly within the body of the assembly.
  • Flexible member 220, seal element 224, and formation 226 are embodied as a single part that is created by insert molding onto disk 222.
  • the interior of cover 202c comprises a circular ridge 202r against which a central annular region of wall 232 bears when spring 228 is biasing seal element 224 maximally away from rim 212.
  • the flow path that communicates chamber space 234 with the nipple forming inlet port 14i' comprises an internal tee passage 14t' extending from the nipple passage.
  • An annular seal 241 that is integrally formed with flexible member 220 seals around the outside of the tee passage where it communicates to chamber space 234.
  • Pressure regulator 200 and valve 14' of the Fig. 6 and 7 embodiment function in the same manner as described above for the earlier embodiment.
  • the coil-containing bobbin 44, 46 and stator parts 48, 50, and 52 are encased in an overmolding 300 to form an assemblage that also includes the body part B2 as part of the overmolding.
  • the overmolding includes features forming the shell of connector 92. The accommodations for acceptance of spring 86 and its associated adjustment mechanism are provided by stator part 48.
  • Stator part 48 is a screw-machined part.
  • Stator part 50 is a strap, rather than a full cylindrical tube. The two parts 48 and 50 are joined together. Part 48 has a head end passing through a hole in a radial portion of strap 50. Part 48 is staked over the margin of the hole in strap 50 to unite the two parts. An axial portion of strap 50 extends from the radially outer end of the strap's radial portion, passing axially over the exterior of coil 44 and extending into contact with stator part 52.
  • stator part 48 covers the coil/bobbin 44, 46, and stator parts as shown, but leaves the outer head end of stator part 48 exposed. This allows access to adjustment screw 88, which is threaded into stator part 48 and contains a polygonally shaped socket 88' for engagement by a correspondingly shaped adjustment tool (not shown).
  • Stator part 48 also contains a hollow interior space for spring 86. One end of spring 86 seats on an internal axial end of screw 88, being centered by a nose in that axial end. The opposite end of spring 86 seats in a counterbore of armature 72.
  • the overmold material forms around a perimeter 399 of a molded plastic part 400 that integrates inlet port 14i', exit 206, and regulator base 202b thereby interlocking the overmold with part 400.
  • the overmold Upon curing of the overmold material, the overmold assumes a final shape as shown.
  • valve seat element 66 is assembled to part 400, the element having a lower cylindrical wall fitted in a sealed manner by an O-ring 402 to the open internal end (co-axial with axis AX) of the nipple that forms inlet port 14i'.
  • the cylindrical tubular wall of the seat element contains several circumferentially spaced apart windows to provide for vapor that has passed through the through-hole controlled by valve 74 to flow to an internal space of part 400 and thence enter regulator chamber space 236.
  • the vapor flow path is indicated by the unnumbered arrows in Figs. 6 and 7.
  • the seat element At its far end, the seat element comprises an annular flange that seats on perimeter 399 of part 400, and a circular rim that fits a short distance into stator part 52.
  • the pintle shaft is guided by bushing 60 while the armature is guided by a thin-walled, non-ferromagnetic sleeve 408.
  • Embodiments utilizing the inventive principles may be constructed in diverse ways. Because automotive electronic technology commonly employs electronic processors, the development of the electric control signal for the solenoid may be accomplished by utilizing conventional software programming techniques to develop the desired waveform or waveforms for any specific control strategy.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Magnetically Actuated Valves (AREA)
  • Fluid-Driven Valves (AREA)
  • Flow Control (AREA)

Claims (14)

  1. Vanne (14') de commande d'écoulement de fluide régulée en pression et actionnée électriquement, comportant :
    un corps (B1, B2) de vanne ;
    un orifice d'entrée (14i') auquel un écoulement fluide pénètre dans le corps (B1, B2) de vanne ;
    un orifice de sortie (14o') auquel un écoulement fluide quitte le corps (B1, B2) de vanne ;
    un mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne situé à l'intérieur du corps (B1, B2) de vanne pour commander l'écoulement de fluide passant par lui ; et
    un régulateur (200) de pression connecté au corps (B1, B2) de vanne, le régulateur (200) de pression comportant un corps (202, 202b, 202c, 202n ; 202r) enfermant un espace (234, 236) intérieur, un trajet d'écoulement passant par le corps (202, 202b, 202c, 202n ; 202r) ayant une entrée (204) connectée à l'orifice de la sortie (14o') et une sortie (206), et un mécanisme (220, 222, 224, 228, 232) de régulation de pression pour réguler la pression à l'entrée du trajet d'écoulement ;
       caractérisé en ce que le mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne a une caractéristique de réponse en fréquence qui le rend incapable de suivre de manière fidèle la fréquence fondamentale d'un signal de commande électrique dont la fréquence fondamentale est supérieure à une fréquence déterminée à l'avance qui, lorsqu'il est appliqué à la commande du mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne, positionne le mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne en une position correspondant à une moyenne temporelle la plus récente du signal de commande électrique sans aucune pulsation significative du mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne ;
       et en ce que le mécanisme (220, 222, 224, 228, 232) de régulation de pression comporte une paroi (232) mobile imperméable aux fluides divisant l'espace (234, 236) intérieur en un premier espace (234) de chambre à volume variable et un deuxième espace (236) de chambre à volume variable, le premier espace (234) de chambre étant connecté à l'orifice d'entrée (14i') et le deuxième espace (236) de chambre formant une partie du trajet d'écoulement entre l'entrée (204) et la sortie (206), le mécanisme (220, 222, 224, 228) de régulation de pression régulant la pression à l'entrée (204) à une pression qui est sensiblement indépendante de la pression à la sortie (206), pour ainsi faire en sorte que l'écoulement passant par la vanne (14') soit sensiblement indépendant des variations de pression à l'orifice d'entrée (14i').
  2. Vanne suivant la revendication 1, dans laquelle la sortie (206) est en communication avec un vide pouvant varier.
  3. Vanne suivant la revendication 1 ou 2, dans laquelle l'entrée (204) comporte un raccord externe, et la vanne comporte en outre un conduit (208) connectant le raccord à l'entrée (14i').
  4. Vanne suivant l'une quelconque des revendications précédentes, dans laquelle le corps (B1, B2) de vanne et le corps (202, 202b, 202c, 202n ; 202r) de régulation de pression sont assemblés ensemble pour former une enveloppe par l'intermédiaire de laquelle un écoulement fluide passe du mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne vers le mécanisme (220, 222, 224, 228, 232) de régulation de pression.
  5. Vanne suivant l'une quelconque des revendications précédentes, dans laquelle la paroi (232) mobile comporte un disque (222) rigide disposé centralement sur la paroi mobile et un élément (220) souple dans lequel est circonscrit le disque (222), le disque (222) comportant un élément (224) d'étanchéité disposé centralement sur lui.
  6. Vanne suivant la revendication 5, dans laquelle le mécanisme (220, 222, 224, 228, 232) de régulation de pression comporte un ressort (228) enroulé de manière hélicoïdale ayant une extrémité axiale portant contre le disque (222) et dans lequel est circonscrit l'élément (224) d'étanchéité.
  7. Vanne suivant la revendication 6, dans laquelle le ressort (228) enroulé hélicoïdalement et l'élément (224) d'étanchéité sont disposés dans le deuxième espace (236) de chambre à volume variable.
  8. Vanne suivant l'une quelconque des revendications 4 à 7, dans laquelle le mécanisme (220, 222, 224, 228, 232) de régulation de pression comporte en outre un conduit à paroi ayant une extrémité (212) ouverte disposée dans la deuxième chambre (236) à volume variable en juxtaposition avec le disque (222) et conduisant à la sortie (206), l'élément (220) souple permettant un mouvement sans restriction du disque (222) par rapport à l'extrémité (212) ouverte du conduit à paroi.
  9. Vanne suivant la revendication 8, dans laquelle le ressort (228) sollicite le disque (222) pour l'éloigner de l'extrémité (212) ouverte du conduit à paroi.
  10. Vanne suivant l'une quelconque des revendications précédentes, dans laquelle le mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne comporte un actionneur (S) d'électroaimant linéaire auquel le signal de commande électrique est appliqué.
  11. Vanne suivant la revendication 10, dans laquelle l'actionneur (S) d'électroaimant linéaire comporte une bobine (44), un enroulement (46) sur la bobine (44) auquel le signal de commande électrique est appliqué, une structure (48, 50, 52) de stator associée à l'enroulement (46), et un surmoulage (300) réunissant la bobine (44) et la structure (48, 50, 52) de stator en assemblage et recouvrant l'enroulement (46).
  12. Vanne suivant la revendication 10 ou 11, comportant en outre un circuit de commande électrique pour fournir le signal électrique à l'actionneur (S) d'électroaimant linéaire à la fréquence fondamentale sensiblement supérieure à la caractéristique de réponse en fréquence du mécanisme (S, 46, 70, 72, 74, 74a, 74b, 74c, 74d, 76, 78, 80) de vanne.
  13. Vanne de purge de vapeur de carburant pour purger les vapeurs de carburant d'un réservoir (16) de carburant vers un collecteur (18) d'admission d'un moteur (20) à combustion interne comportant une vanne suivant l'une quelconque des revendications précédentes, le premier espace (234) de chambre étant en communication avec l'espace de tête du réservoir de carburant.
  14. Vanne de purge de vapeur de carburant suivant la revendication 13, dans laquelle le premier espace (234) de chambre est en communication avec l'espace de tête de réservoir de carburant par l'intermédiaire d'un canister (12 ; 237) de récupération de vapeur de carburant.
EP98931868A 1997-07-25 1998-07-09 Electrovanne lineaire a purge regulee Expired - Lifetime EP0998629B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US90097697A 1997-07-25 1997-07-25
US900976 1997-07-25
PCT/CA1998/000663 WO1999005408A1 (fr) 1997-07-25 1998-07-09 Electrovanne lineaire a purge regulee

Publications (2)

Publication Number Publication Date
EP0998629A1 EP0998629A1 (fr) 2000-05-10
EP0998629B1 true EP0998629B1 (fr) 2002-10-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP98931868A Expired - Lifetime EP0998629B1 (fr) 1997-07-25 1998-07-09 Electrovanne lineaire a purge regulee

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EP (1) EP0998629B1 (fr)
JP (1) JP3452900B2 (fr)
KR (1) KR100356943B1 (fr)
AU (1) AU8203498A (fr)
DE (1) DE69808638T2 (fr)
WO (1) WO1999005408A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5970958A (en) * 1997-10-10 1999-10-26 Eaton Corporation Fuel vapor purge control
WO2000077427A2 (fr) * 1999-06-14 2000-12-21 Siemens Canada Limited Robinet de purge de carter pour flux d'air a forte regeneration
KR20060035118A (ko) * 2004-10-21 2006-04-26 김종하 엘피지 차량의 엘피엘아이 시스템용 가변식 엘피지압력조절장치
KR100748662B1 (ko) * 2005-12-10 2007-08-10 현대자동차주식회사 자동차의 증발가스 리크 진단장치 및 방법
US9488137B2 (en) 2011-03-22 2016-11-08 Illinois Tool Works Inc. Systems and methods for controlling fuel vapor flow in an engine-driven generator
US9109549B2 (en) 2011-03-22 2015-08-18 Illinois Tool Works Inc. Systems and methods for controlling fuel vapor flow in an engine-driven generator
KR101396739B1 (ko) * 2013-04-30 2014-05-16 주식회사 현대케피코 퍼지 컨트롤 솔레노이드 밸브
EP3303814B1 (fr) * 2015-06-02 2020-12-30 Illinois Tool Works Inc. Systèmes et procédés de commande d'écoulement de vapeur de carburant dans un générateur entraîné par un moteur
KR101756795B1 (ko) 2015-12-11 2017-07-11 주식회사 현대케피코 퍼지 제어 스테핑 모터

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5069188A (en) * 1991-02-15 1991-12-03 Siemens Automotive Limited Regulated canister purge solenoid valve having improved purging at engine idle
US5509395A (en) * 1995-03-31 1996-04-23 Siemens Electric Limited Canister purge flow regulator
US5551406A (en) * 1995-05-19 1996-09-03 Siemens Electric Limited Canister purge system having improved purge valve
US5649687A (en) * 1995-06-06 1997-07-22 Borg-Warner Automotive, Inc. Pulse width modulated solenoid purge valve

Also Published As

Publication number Publication date
KR20010022193A (ko) 2001-03-15
AU8203498A (en) 1999-02-16
KR100356943B1 (ko) 2002-10-18
DE69808638T2 (de) 2003-06-26
EP0998629A1 (fr) 2000-05-10
WO1999005408A1 (fr) 1999-02-04
JP2001511547A (ja) 2001-08-14
DE69808638D1 (de) 2002-11-14
JP3452900B2 (ja) 2003-10-06

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