• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A carburetor fuel flow control device having an elongate annular body received in a cavity with an inlet in its sidewall communicating with a fuel supply passage and an outlet downstream of the inlet and adjacent to an end of the body, and a needle valve with a metering portion adjacent one end rotatably and slidably received in the body with the metering portion at least partially lapping or blocking the inlet to change the effective flow area of the inlet in response to generally axial movement of the needle valve relative to the inlet.
    公开号:SE1750949A1
    申请号:SE1750949
    申请日:2016-02-03
    公开日:2017-07-19
    发明作者:Nagata Noriyu；Sasaki Hidenori；Sasaki Masashi；Sato Daisuke；Terakado Hitoshi
    申请人:Walbro Llc；
    IPC主号:
    专利说明:

    CARBURETOR FUEL CONTROL Reference to Co-Pendíng ApplicationsThis application claims the benefit of U.S. Provisional Patent ApplicationNo. 62/ 1 1 1,717 filed February 4, 2015 which is incorporated herein by reference in its entirety.
    Technical FieldThe present disclosure relates generally to carburetors and more particularly to a fuel control device for a carburetor.
    Background Many carburetors for gasoline powered utility engines have a needle valveassembly for adjusting the flow rate of fuel supplied to an air and fuel miXing passageof the carburetor. The needle valve has a shank threadably received in a cavity in acarburetor body and a tapered or conical tip which cooperates with an annular valveseat in the cavity to vary and control the flow rate of fuel passing between them by rotating the valve to advance or retract the conical tip relative to the valve seat.
    Summary ln some implementations a somewhat fleXible body with a central passageis received in a carburetor valve cavity and has an aXially elongate inlet passagecommunicating with a fuel supply passage and an outlet downstream of the inlet, anda needle valve having a shank received in the valve cavity with a cylindrical meteringportion slidably and rotatably received in the central passage and aXially movable toat least partially block the inlet to change the effective flow area of the inlet into thecentral passage. ln some implementations the cylindrical metering portion is receivedin the central passage with an interference fit and the needle valve is in one piece,threadably engaged with the valve cavity, and has a head with a tool engaging feature for rotating the needle valve.
    Brief Description of the Drawings The following detailed description of certain embodiments and best modewill be set forth with reference to the accompanying drawings, in which: FIG. 1 is a cross sectional view of one implementation of a carburetorhaving a fuel control device; FIG. 2 is a fragmentary sectional view showing a portion of a body of thecarburetor and the fuel control device; FIG. 3 is a fragmentary sectional view showing a portion of a body of thecarburetor and a portion of the fuel control device; FIG. 4 is a side view of a metering body; FIG. 5 is a cross sectional view of the metering body; FIG. 6 is a graph showing changes in idle fuel flow rate with adjustmentsto representative fuel flow devices; FIG. 7 is a cross sectional view of a rotary throttle valve carburetor with afuel control device; FIG. 8 is a fragmentary sectional view of a modified form of the fuelcontrol device in a carburetor body; and FIG. 9 is a sectional view of a modified body of the fuel control device of FIG. 8.
    Detailed Description Referring in more detail to the drawings, FIG. 1 illustrates a fuel controldevice 8 for a carburetor such as a float bowl, rotary barrel valve, butterfly valve ordiaphragm type carburetor 11. The fuel control device 8 is at least partially receivedin a bore or cavity 12 of a carburetor body 14 and is adjustable to meter and control orlimit the flow rate of fuel delivered from the carburetor. The carburetor 11 may be adiaphragm type carburetor that has a flexible diaphragm 15 that controls the pressureof fuel in a fuel metering chamber 16. The fuel metering chamber 16 communicateswith the cavity 12 through a passage 18 and the fuel control device 8 controls the rateof fuel flow through an outlet bore 20 to a nozzle bore 21 in the carburetor body 14.The nozzle bore 21 contains a nozzle 22 or orifice through which fuel is drawn into afuel and air miXing passage 23 to be mixed with the air flowing therethrough, with the resulting fuel and air mixture then being supplied to an operating engine.
    Accordingly, adjustment of the fuel flow rate past the fuel control device 8 affects thefuel flow rate to and through the nozzle 22 and hence, the richness of the fuel and airmiXture delivered to the engine.
    The fuel control device 8 may, in at least some implementations, take theform of a needle valve and one or more such valves may be provided in a carburetor.At least some implementations of the carburetor may include two needle valves 10rotatably carried by the carburetor body 14 in separate cavities 12 (only one of whichis shown) formed in the body. Rotation of the needle valves 10 relative to thecarburetor body 14 in one direction advances the needle valves further into thecarburetor body and rotation in the other direction retracts the needle valve from thecarburetor body. Such rotation of the needle valves 10 moves an end portion 24 of theneedle valve relative to a port or the passage 18 to control the flow rate of fuelthrough that port or passage. In the implementation shown, one needle valve controlsfuel flow through part of a low speed fuel circuit and the other needle valve controlsfuel flow through part of a high speed fuel circuit. Each needle valve 10 may receive alimiter cap to control or limit rotation of the valves and hence, adjustment of the flowrate of fuel through the respective fuel circuit in the carburetor 10. The needle valves10 may be arranged generally parallel to each other, side-by-side, and may be rotatedindependently of each other through at least a portion of their adjustment range. Eachneedle valve 10 and cavity 12 may have the same features and so only one needlevalve 10 and cavity 12 will be shown and described in detail. The needle valve 10shown in FIG. 1 is representative and the needle valve 10 shown in FIGS. 2 and 3illustrate one presently preferred implementation of the needle valve. Of course, otherarrangements may be used.
    The needle valve 10 may have a shank 28 with a threaded portion 30 thatengages complementary threads formed in the cavity 12, or in a retainer 26 adjacentto or partially received in the cavity 12. A head 32 of the needle valve 10 may eXtendaXially from a rear end of the shank 28 and, in order to rotate and adjust the valve 12,a tool receiving feature, such as a recess or slot 34 may be defined in the head 32 tofacilitate rotation of the needle valve 10. Of course, the tool receiving feature 34 maybe formed in any desired shape or orientation, and may include a projection ratherthan a cavity or slot. The needle valve 12 may include one or more shoulders 44 or other features adapted to provide a stop surface limiting advancement of the needle Valve into the carburetor body 14 or to engage a seal within the carburetor body 14 toinhibit or prevent fuel leaking from the carburetor 10.
    The shank 28 and needle valve 10 generally, may be symmetrical about anaXis 46 of rotation, and may be concentric with an aXis 47 of the cavity 12. Thecavity 12 may be defined at least in part by or include or communicate with the outletbore 20 which may be spaced from the end portion 24 of the needle valve 10 andleading to the main fuel nozzle passage 21 and one or more counterbores 50 thatdefine radially inwardly eXtending shoulders that may be generally complementarilyarranged with respect to the shoulders and corresponding surfaces of the needle valveso that the needle valve is closely received within the cavity. At least one cavityshoulder 52 may be engaged by a needle valve shoulder to define a fully inserted oradvanced position of the needle valve 10 relative to the carburetor body 14. In at leastsome implementations, the needle valve shoulder 44 is located between the threadedportion 30 and the end portion 24, and is shown in FIG. 2 as being locatedimmediately adjacent to the threaded portion 30. This shoulder 44 engages the cavityshoulder 52 at an outer surface of or entrance to the cavity 12, in the implementationshown.
    The end portion 24 of the needle valve 10 may include or define ametering portion that adjusts the size or flow area of the fuel flow path between thepassage 18 and the bore 20. In at least some implementations, the metering portion24 is defined by or includes an aXial end 54 of the needle valve 10, although themetering portion could be spaced from the end 54. ln the implementation shown, themetering portion 24 is defined by the end portion of the needle valve and iscylindrical, with a constant diameter. Of course, other shapes and arrangements maybe used as desired, and the metering portion 24 may be defined by all or only aportion of the constant diameter end portion, or otherwise shaped end portion.
    To control the flow rate of fuel as indicated above, the metering portion 24of the needle valve is adjusted or moved relative to a port or passage through whichfuel flows. The port or passage may be defined within the carburetor body itself, or ina separate component. In at least some implementations, including that shown inFIGS. 2 and 3, a flow control body 58 is received within the cavity 12 and includes aninlet 60 in fluid communication with the passage 18 and an outlet 62 in fluid communication with the bore 20 and fuel nozzle bore 21 downstream thereof. The body 58 may be generally cylindrical and has a central passage 64 in which at least aportion of the needle valve metering portion 24 is received, and the central passagemay be concentrically and coaXially aligned with the metering portion. In theimplementation shown, a portion of the central passage 64 not occupied by the needlevalve 10 communicates the inlet 60 with the outlet 62 to provide a fuel flow pathbetween them. At least this portion of the central passage 64, up to and including allof the central passage 64, is parallel to and preferably coaXial with the meteringportion 24. The inlet 60 may be defined by a void or opening through the body 58that is not parallel to the central passage 64, and in the implementation shown, isperpendicular to the central passage. The inlet 60 may be directly aligned with thepassage 18 such that at least a portion of the inlet radially overlaps (relative to an aXisof the passage 18) or is aXially aligned (relative to the aXis 46) with the passage 18such that fuel may flow directly from the passage 18 through the inlet 60. This maysimplify the flow path by removing one or more turns or bends through which the fuelwould otherwise have to flow to reach the outlet 62. The inlet 60 may be defined by aslot formed through a wall of the body. The inlet 60 may have any desired size andshape. In the implementation shown, the intersection of the inlet 60 and the centralpassage 64 is a rectangle having constant width (in the circumferential direction) overits aXial length. This aXially elongate rectangular configuration negates the adverseaffect of fuel viscosity variations and decreases the likelihood of fuel vaporization.The inlet 60 may be tapered, as shown in FIGS. 4 and 5, such that the circumferentialwidth (relative to aXis 46) of the inlet 60 increases from the inner surface 66 to itsouter surface 68. This may help to funnel fuel into the inlet and/or it may facilitatemolding the body 58 and removing the body from the tool or mold used to form thebody. The sidewalls 69 of the inlet may be inclined or tapered relative to each otherat an acute inclined angle in the range of about 45° to 75°, desirably 50° to 70° andpreferably about 60°.
    The flow control body 58 may include a mid-section 70 with a reducedouter diameter compared to portions 72, 74 of the body aXially outboard of the mid-section. The portions 72, 74 aXially outboard of the mid-section, in at least someimplementations, include the ends of the body 58 and are received with aninterference fit within the cavity 12. The inlet 60 is formed in the mid-section 70 andany fuel that does not flow through the inlet may be received in a circumferential/annular gap 76 (FIG. 3) between the body and the carburetor body 14,and that fuel may eventually flow into the inlet. The enlarged diameter ends 72, 74engage the carburetor body 14 and may provide a seal outboard of the mid-section 70to prevent or substantially inhibit fuel from leaking out of the gap 76. The body 58may be formed of an at least somewhat flexible material and may accommodate someeccentricity or misalignment of the metering portion 24 relative to the cavity 12, suchas may occur, for example, when the threads of the threaded portion 30 are notconcentric with at least a portion of the cavity 12. At least an inlet end 78 of the bodymay include a tapered inner surface 80 (FIG. 3), providing a larger inner diameter atthe outer end than at locations toward the mid-section 70. This may facilitate receiptof the needle valve metering portion 24 within the passage 64, and may also provideclearance (or less interference) between the metering portion and at least part of theenlarged diameter end 74. With this clearance, the primary contact between themetering portion 24 and the body 58 may be within the mid-section 70 which mayfleX relative to the carburetor body 14 (due at least in part to the gap 76 betweenthem) to accommodate at least some misalignment of the metering portion 24 andcavity 12. The contact within the mid-section 70 also provides a seal between themetering portion 24 and the body 58 to prevent or at least inhibit fuel from leakingbetween them. The diameter of the metering portion 24 may be equal to or slightlylarger than the inner diameter of at least a portion of the mid-section 70 (e. g. a portionadjacent to the inlet end 78 and leading to the inlet 60). In at least someimplementations, this may reduce or eliminate changes in the fuel flow rate due toeccentricity between the needle valve 10 and cavity 12, or cocking or side loading ofthe needle in use, as the size of the open area of the inlet 60 would not be affected bysuch things nor would the seal between the metering portion 24 and body 58.
    The flow control body 58 may be installed into the cavity 12 in any desiredmanner. In one method, the body 58 is pressed partially onto the metering portion 24of the needle valve 10 (e. g. in an orientation to ensure desired alignment of the inlet60 with the carburetor passage 18 when fully installed) and the needle valve 10 isinstalled into the cavity 12. The body 58 will be pressed into the counterbore 50 inthe cavity 12 and will eventually engage a needle valve shoulder 82 adjacent to themetering portion 24. The fully installed position of the body 58 may coincide with the fully advanced position of the needle valve 10 wherein the needle shoulder 44 engages the cavity shoulder 52 as described above. In this position, the meteringportion 24 aXially overlaps and blocks at least a portion of the inlet 60 and therebyreduces the effective floW area of the inlet through Which fuel may floW. From thisfully advanced position, the needle valve 10 may be rotated in the opposite directionto at least partially back out or WithdraW the metering portion 24 from the body 58(i.e. move the needle valve aXially relative to the body) and open or further open theinlet 60, thereby increasing the effective floW area of the inlet. Instead of putting thebody 58 onto the metering portion 24 before the needle valve 10 is inserted into thecavity 12, the body 58 can be at least partially pressed into the counterbore 50, using aseparate tool, before the needle valve 10 is installed into the cavity 12. For thispurpose, the body 58 may include an alignment feature, such as a notch 84 (FIG. 4),that may facilitate installing the body in a desired orientation, With the inlet 60directly overlapping/aligned With the passage 18. lf desired, the fully installedposition of the body 58 may be achieved upon moving the needle valve 10 to its fullyadvanced position as in the other method. This may help to consistently define thefully installed position of the body 58 across a production run of carburetors 11 andreduce variation among carburetors. Consistent positioning of the body 58 and needlevalve 10 may facilitate calibration of the fuel floW in the carburetor.
    Conventional needle valves utilize a tapered tip of the needle that is aXiallymovable relative to a valve seat to increase or decrease the Width of an annular floWgap between the tip and the carburetor body. The radial Width of the annular gap issmall and subject to becoming at least partially clogged by debris, including but notlimited to particles of filtration material, Which reduces the effective floW area of thefloW gap. Further, eccentricity between the tapered tip and carburetor body providesan uneven floW gap (radially smaller in some areas and larger in others) that changesthe fuel floW characteristics therethrough. Further, the tapered tip provides a non-linear change to the floW gap area for a given aXial movement of the needle valve, andthis can decrease the sensitivity of the needle valve (i.e. a small aXial movement mayresult in a large change in fuel floW rate). These things individually or in combinationcan make calibration of the carburetors difficult because of the significantly differentfuel floW characteristics that may be found among a production run of carburetors.That is, the amount of adjustment of the needle valve to achieve a desired fuel floW rate may vary more among different carburetors in a production run.
    In at least some implementations, the metering portion 24 has a constantdiameter, and the inlet 60 has a uniform width along its aXial length and this perrnits alinear change to the open surface area of the inlet (its effective flow area) for a givenaXial movement of the needle valve 10. Further, instead of using an annular gap ofrelatively small width, the inlet 60 is provided in one open area whose smallestdimension is considerably larger than the radial width of the annular gap in priorneedle valves. Hence, the inlet 60 is not prone to being clogged with debris. In atleast some implementations, the smallest dimension of the flow area of the inlet 60 isat least 140um and in some implementations may be 200um or more. Further, thelarger open area of the inlet facilitates fuel flow therethrough and reduces the numberof turns and small gaps through which the fuel must flow, all of which tend toincrease vapor generation in the fuel, especially when the carburetor may be at anelevated temperature.
    Rotation of the needle valve 10 moves the metering portion 24 aXiallywhich uncovers or increasingly covers more of the aXial length of the inlet 60, asdesired, to provide a desired effective flow area of the inlet. Eccentricity between theneedle valve 10 and cavity 12 is accommodated and does not change the flow area ofthe inlet or render the inlet more susceptible to blockage from debris. The linearmovement of the metering portion and uniform width of the inlet provides greaterconsistency among carburetors. The ability to reliably calibrate and control fuel flowthrough the inlet is improved and the interference fit between the needle valve 10,flow control body 58 and carburetor body 14 resist unintended movement of themetering portion 24 relative to the inlet 60 such as may be caused by vibration orother forces in use of the carburetor. The straight and constant diameter meteringportion 24 (in implementations were such is provided), also resists breaking duringinstallation, such as sometimes occurs with tapered needle valve tips, for example,when fully advanced and not concentric with the valve seat that they engage. In atleast some implementations, the metering portion 24 does not directly engage thecarburetor body 14 and instead engages only the flow control body 58 which may bemade of a polymeric or metallic material, as desired (if made of metal, appropriate o-rings or other seals may be used to provide a seal between the metering portion andbody). A polymeric body 58 avoids the porosity problems with cast aluminum carburetor bodies in the area of the cavity and seat for conventional needle valve assemblies. A suitable polymeric material of body 58 may be POM such as DuraconM90-44.
    FIG. 6 illustrates the improved control of fuel flow that may be achievedby at least some implementations of the needle valve 10 and flow control body 58 incarburetors. Plot lines 90, 92 and 94 represent fuel flow rates achieved in threedifferent carburetors having a needle valve 10 and flow control body 58 as describedherein. The flow rates through the inlet 60 of the flow control bodies are plotted as afunction of the position of the metering portion 24 relative to the body 58. The flowrates were measured at idle engine operation. Plot line 96 shows the flow rate througha needle valve having a tapered tip according to the prior art. The prior art valvearrangement requires greater movement of the needle valve to achieve a calibratedfuel flow rate, which is shown by line 98. And the variance among different prior artcarburetors including the same valve arrangement is greater than the relatively smallvariation shown by plot lines 90, 92, 94 which all show a calibrated fuel flow rate atabout 2.25 rotations of the needle valve. This low variability among the differentcarburetors facilitates calibration and control of fuel flow within the carburetors.
    FIG. 7 illustrates a rotary throttle valve carburetor 100 including a fuelcontrol device 102. FIGS. 1-5 illustrate use of the fuel control device in a butterfly-type carburetor, having a butterfly type throttle valve. The rotary throttle valve orbarrel type carburetor 100 shown in FIG. 7 includes a throttle valve 104 that rotatesabout an aXis 106 to increasingly vary the alignment of a throttle bore 108 formed inthe throttle valve 104 with a fuel and air miXing passage 110 to thereby vary the fluidflow rate through the fuel and air miXing passage. As the throttle valve 104 rotates, italso moves aXially (e. g. as controlled by a cam surface) to move a needle 112 relativeto a main fuel nozzle 114 and thereby control the fluid flow rate through the main fuelnozzle. The fuel control device 102 may be received within a fuel circuit or fuel path116 between the main fuel nozzle 114 and a metering chamber 118. As in thepreviously described embodiments, the fuel control device 102 may include a flowcontrol body 120 and a needle valve 122. The flow control body 120 may beconstructed in the same manner as the flow control body 58 already described, andmay have an inlet 124 communicated with an outlet 126 via a passage 128. The needle valve 122 may also be the same as or similar to the needle valve 10 and have a metering portion 130 that may be at least partially received in the passage 128 to, in at least certain positions, at least partially block the inlet 124 to control the fluid flowrate through the inlet. The outlet 126 is communicated with the main fuel nozzle 114through one or more passages or openings of the fuel path 116. The flow controlbody 120 and needle valve 122 may be installed into the carburetor 100 and mayfunction in the same manner as previously described, if desired. The rotary valvecarburetor 100 may be constructed as disclosed in U.S. Patent No. 7,114,708 thedisclosure of which is hereby incorporated by reference in its entirety.
    FIGS. 8 and 9 illustrate a modified form of a flow control body 58”received in a valve cavity 12” of a carburetor body. As shown in FIG. 8 the valvecavity 12” has a nozzle bore 20 communicating with a nozzle orifice passage 21which preferably is coaXial with a counterbore 140 receiving an end portion of body58” desirably with an interference fit to provide a seal between them, a secondcounterbore 142 with a somewhat larger diameter providing an annular gap or space76 between the body and the cavity and communicating with the fuel supply passage18, and desirably also receiving a circumferential rib 144 of the body preferably withan interference fit to provide a seal between them. A coaxial threaded thirdcounterbore 146 receives a complentarily threaded portion 30 of a shank of a needlevalve 10” and preferably a fourth coaxial counterbore 148 receives a head 32 of theneedle valve. Desirably, the head 32 has a slot or other tool receiving feature tofacilitate rotation of the needle valve to adjust the valve assembly. The counterbore148 may blend into a chamfer or coaxial frusto-conical bore 150 opening onto anexterior of the carburetor body 14. Desirably the head 32 will have a configurationwhich cannot be engaged by conventional readily available tools such as ascrewdriver, socket, Allen wrench, etc. to rotate the needle valve so that the valveassembly cannot be adjusted by an end user.
    As shown in FIG. 9, the flow control body 58” has an aXially elongatethrough bore 64 which adjacent one end opens into a frusto-conical bore 160 tofacilitate insertion of the needle valve 10” into the body. The body has an outer aXialelongate cylindrical surface 162 desirably coaXial with the bore 64 and in assemblyreceived in the cavity counterbore 142 and has a diameter providing an annular spaceor gap 76 between them which communicates with the fuel supply passage 18.Desirably the diameter of this cylindrical surface 162 is also slightly larger than the diameter of the cavity counterbore 140 to provide in assembly an interference fit creating a seal between them. Desirably the cylindrical surface 162 blends into achamfer or frusto-conical surface 164 eXtending to the end 166 of the body tofacilitate insertion of the end portion of the body into the cavity counterbore 140during assembly. In a central portion the body has a through and aXially elongate slotor inlet 60 desirably with tapered or inclined sidewall surfaces 69. This inlet 60communicates with the fuel flow passage 18, the annular space or gap 76, and theinterior central passage or bore 64 of the body 5 8”.
    Adjacent the other end 170 the body has a circumferentially continuous rib144 which desirably has a diameter somewhat larger than the diameter of the cavitycounterbore 142 to provide in assembly a press fit or interference fit providing a sealbetween the body and the carburetor. Desirably this rib has a chamfer orfrusto-conical surface 176 on the aXially inner edge of the rib to facilitate insertion ofthe body 5 8” into the counterbore 142.
    As shown FIG. 8, the valve 10” is desirably in one piece and has a shankwith the cylindrical metering portion 24 adjacent one end, a head 32 adjacent its otherend and, a threaded portion 28 between them engagable with complementary threadsin the cavity counterbore 146 so that in assembly rotation of the needle valve in onedirection advances the cylindrical portion 24 relative to the inlet 60 and rotation in theother direction retracts the cylindrical portion relative to the inlet to thereby changethe effective area through the cylindrical metering portion 24 preferably has adiameter slightly larger than the diameter of the bore 64 of the control body to providein assembly an interference fit to provide a fluid seal between them in at least aportion of the bore 64 between the outer end 170 and the adjacent aXial end of theinlet 60 which fuel flows into the bore 64 of the body and through its outlet end 166.Desirably the needle valve has an essentially radially eXtending or right angleshoulder 82” which may facilitate use of the needle valve to initially insert andposition the control body 58” into assembled relationship in the counterbores 140 and142 of the valve cavity 12”. In some implementations this shoulder 82” may alsoengage a complementary annual shoulder between counterbore 144 and 146 of thevalve cavity 12” to provide a positive stop limiting the extent to which the valveassembly may be inserted into the cavity and/or the cylindrical portion 24 into the control body 5 8”. 11 The control Valve body 58” may be assembled With an interference fit orpress fit into the counterbores of 140 and 142 of the valve cavity 12” in at least thesame Ways as described above With respect to assembly of the control body 58 intothe cavity 12 and thus these Ways are incorporated hereat by reference and Will not berepeated.
    While the forms of the invention herein disclosed constitute presentlypreferred embodiments, many others are possible. It is not intended herein to mentionall the possible equivalent forms or ramifications of the invention. It is understoodthat the terms used herein are merely descriptive, rather than limiting, and that various changes may be made Without departing from the spirit or scope of the invention. 12
    权利要求:
    Claims (20)
    [1] 1. A carburetor fuel floW control device, for a carburetor having a mixingpassage, a valve cavity, a fuel supply passage opening into the cavity and a fuel outletfrom the cavity, the device comprisin g: an annular body of a someWhat flexible material having a sideWall and anaxially elongate central passage through the body, the body adjacent each end havinga circumferentially continuously exterior surface engaging a complementary portionof the valve cavity, an inlet through the sideWall communicating the supply passageWith the central passage, and an outlet doWnstream of the inlet; and a needle valve having a shank received in the cavity and a cylindricalmetering portion slidably and rotatably received With at least a close fit in the centralpassage and axially movable to at least partially block the inlet to reduce the effective floW area of the inlet into the body passage.
    [2] 2.The device of claim 1 Wherein the cylindrical metering portion has at leasta portion With a circumferentially continuous interference fit With a portion of the body upstream of the inlet.
    [3] 3.The device of claim 1 Wherein an exterior circumferential portion of thebody doWnstream of the inlet has an interference fit With a complementary portion of the cavity to provide a seal between them.
    [4] 4.The device of claim 1 Wherein a portion of an exterior surface of the bodyupstream of the inlet has an interference fit With a complementary portion of the cavity to provide a seal between them. 13
    [5] 5. The device of claim 1 wherein at least part of the cylindrical meteringportion has an interference fit with the body, and the device further comprises anannular space between the exterior of the body and the cavity with the supply passage and the inlet communicating with the annular space.
    [6] 6.The device of claim 5 wherein the exterior surface of the body alsocomprises a circumferentially continuous recess between and spaced aXially inwardlyfrom the ends of the body and at least in part forming the annular space between the body and the cavity.
    [7] 7.The device of claim 1 wherein the central passage and the exterior surface of the sidewall of the body are substantially coaXial.
    [8] 8. The device of claim 1 wherein the inlet is aXially elongate.
    [9] 9.The device of claim 8 wherein the inlet has a substantially uniform width along its aXial length.
    [10] 10.The device of claim 8 wherein the inlet has tapered surfaces configured so that its circumferential width increases from the inner surface to the outer surface.
    [11] 11.The device of claim 10 wherein the tapered surfaces form an included angle in the range of 50 degrees to 70 degrees. 14
    [12] 12.The device of claim 1 wherein the inlet is generally rectangular and has a substantially uniform circumferential width along its axial length.
    [13] 13.The device of claim 1 wherein the body also comprises a circumferentially continuous rib adjacent its end upstream of the inlet.
    [14] 14.The device of claim 13 wherein the rib has an outer circumferentiallycontinuous surface having an interference fit with a complementary portion of the valve cavity to provide a seal between them.
    [15] 15.The device of claim 13 wherein a rib has a tapered portion adjacent itsaxially inboard end having a minimum diameter less than the maximum diameter of the rib portion.
    [16] 16.The device of claim 1 wherein the central passage merges into a chamferedsurface having a maximum diameter adjacent an axially outboard end of the body which is greater than the diameter of the central passage.
    [17] 17. The device of claim 1 wherein the needle valve also comprises a headadjacent an end of the needle valve generally axially opposite to the cylindricalmetering portion of the needle valve, and the head is received in the valve cavity andhas a tool engagement feature configured for engagement with only anon-conventional tool in order to rotate the valve to change the extent to which thecylindrical portion at least partially blocks the inlet to change the effective flow area of the inlet.
    [18] 18.The device of claim 16 Wherein the tool engagement feature of the head has a non-circular configuration.
    [19] 19. A carburetor for an engine comprising: a carburetor body including a miXing passage, a valve cavity, a fuel supplypassage opening into the cavity and a fuel outlet from the cavity; an annular body of a someWhat fleXible material having a sideWall and anaXially elongate central passage through the body, the body adjacent each end havinga circumferentially continuously exterior surface engaging a complementary portionof the valve cavity, an inlet through the sideWall communicating the supply passageWith the central passage, and an outlet doWnstream of the inlet; and a needle valve having a shank received in the cavity and a cylindricalmetering portion slidably and rotatably received With at least a close fit in the centralpassage and aXially movable to at least partially block the inlet to reduce the effective floW area of the inlet into the body passage.
    [20] 20.The carburetor of claim 19 Wherein the cylindrical metering portion has atleast a portion With a circumferentially continuous interference fit With a portion of the annular body upstream of the inlet. 16
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    CN210564817U|2020-05-19|Carburetor for improving reliability of mixed gas adjustment
    US1882836A|1932-10-18|Gas range cock
    US1184355A|1916-05-23|Fuel-injector for oil-engines.
    US2118013A|1938-05-17|Gas valve
    同族专利:
    公开号 | 公开日
    US20180023514A1|2018-01-25|
    CN107208574B|2021-04-06|
    DE112016000601T5|2017-11-23|
    WO2016126839A1|2016-08-11|
    SE541980C2|2020-01-14|
    US10890140B2|2021-01-12|
    CN107208574A|2017-09-26|
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    法律状态:
    2020-09-29| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    US201562111717P| true| 2015-02-04|2015-02-04|
    PCT/US2016/016397|WO2016126839A1|2015-02-04|2016-02-03|Carburetor fuel control|
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