Classifications

• • 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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
  • F02M61/165—Filtering elements specially adapted in fuel inlets to injector
• • 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
  • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
  • F02M2200/27—Fuel-injection apparatus with filters

Definitions

• the present invention relates to a fuel injector and more particularly to a filter arranged in the inlet mouth of an injector.
• Fuel injection devices in particular diesel, must remove the particles present in the fuel to protect their operation.
• filters that are arranged in the inlet channel of the injector.
• the filters have cylindrical shapes provided with calibrated holes to retain fine particles, the holes having diameters of the order of 50 to 100 micrometers made by laser drilling.
• the filter manufacturing techniques do not make it possible to stop long and fine particles as well as compact particles whose size is less than 35 micrometers.
• the object of the present invention is to provide a filter which overcomes these disadvantages.
• the present invention aims to overcome the disadvantages mentioned above by providing a filter designed to be arranged in an inlet channel of a pressurized fuel injector for an internal combustion engine.
• the filter has an elongate shape extending along a major axis.
• the filter comprises a filtering outer member whose peripheral wall is provided with a first external series of through holes and an inner filter member whose peripheral wall is provided with a second inner series of through holes, the inner member being inserted concentric in the outer limb.
• the two filtering members define between them an annular space.
• the directory space can be of constant radial thickness.
• the annular space is of non-constant radial thickness.
• the outer filter member and the inner filter member are angularly oriented about the main axis relative to each other so that the holes of the first outer series and the holes of the second inner series are off-axis.
• Dis is the diameter of the inner hole of the second inner series
• D2e is the outer hole diameter of the first outer series
• G is an inter-hole overlap distance greater than or equal to zero.
• each hole of the second inner series of the inner member opens into the annular space in the vicinity of a plurality of holes of the first outer series of the outer member, the axis of said hole of the inner member being equidistant from the axes of said holes of the outer limb.
• the axis of the hole of the inner member may also not be equidistant from the axes of the hole of the outer member.
• the holes have a variable section and the diameter of the inner hole corresponds to the smaller diameter of the hole of the inner member.
• the radial thickness of the annular space is less than or equal to the smallest diameter of the holes of the inner member. In another embodiment, the radial thickness of the annular space may be strictly smaller than the diameter of the smallest section of the holes of the lower limb.
• a fuel injector is provided with a filter described above.
• the filter is arranged in the input channel. The method to realize the filter, comprises the following steps:
• Figure 1 is a longitudinal section of an injector using a filter according to the invention.
• FIG. 2 is an enlarged longitudinal section of the filter of the injector of FIG. 1.
• FIG. 3 is an enlarged longitudinal section of the inner filter inserted into an outer filter according to the preferred embodiment of the invention.
• Figure 4 is a sectional view of the inner holes of the inner member of the filter according to the preferred embodiment of the invention.
• Figure 5 is a sectional view of the outer holes of the outer member of the filter.
• Figure 6 is a radial diagram of the top of Figure 3.
• FIGS 7, 8, 9, schematically the cover of the holes of the filter.
• fuel under high pressure enters an inlet channel 12, circulates in a high pressure circuit and is then sprayed via injection holes located in the nozzle of the injector 10.
• the invention is here described in the context of a diesel injector but could easily be used in a gas injector.
• the fuel under high pressure passes through a filter 14 arranged to retain impurities and other particles that can damage the precision mechanics of the injector 10.
• the particles can be of various shapes such as compact or thin and elongated .
• the filter 14 shown in FIG. 2 has an elongate and cylindrical shape extending along an axis X of the inlet channel 12.
• the axis X corresponds to the longitudinal axis of the filter 14.
• the filter 14 comprises a first fastening portion 16 tightly mounted with interference in the inlet channel 12, this portion defining a fuel inlet section and a second filter portion 18 longer than the first portion 16 and of smaller diameter, the second portion 18 being provided at its periphery numerous filtering holes.
• the fuel enters through the inlet channel 12 and then filtered spring in an annular passage 22 defines between the wall of the inlet channel 12 and the outer wall of the second filtering portion 18.
• the filter 14 comprises a filtering inner member 24 and an outer filter member 26, the inner member 24 being inserted into the outer member 26.
• the filter 14 has a gap E between the inner member 24 and the outer member 26.
• the space E is annular.
• the space E is constant radially and along its length along the axis X in the filtering portion 18 of the filter. In another alternative space E may not be constant and have deviations from one point to another along the circumference or over the length, the deviations may go beyond the usual tolerance of the order of +/- 10 micrometers.
• the outer member 26 is composed of two parts, a first fixing portion 17 and a second filtering portion 19.
• the second filtering portion 19 is of elongate and cylindrical shape and has an inner wall 28 and an outer wall 30.
• the filtering portion 19 comprises a cylindrical tube with a first external series of holes opening 21 and having at one end a spherical tip 32 which closes the outer member.
• the tip 32 of the filtering part 19 may alternatively be flat, ovoid or have any other shape.
• the inner member 24 is inserted into the outer member 26 of the filter.
• the inner member 24 is composed of two parts, a first full tubular portion 34, a second tubular filter portion 36 with a second inner series of through holes 38 of smaller diameter than the first portion 34 and a spherical tip 40 which closes the filtering portion of the inner member 24 located opposite the first portion 34.
• the tip 40 of the filter portion 36 may alternately be flat, ovoid or have any other shape.
• the second filtering portion 36 is of elongate and cylindrical shape and has an inner wall 37 and an outer wall 39.
• the holes 20 of the filter 14 comprise the filtration holes 38 of the inner member 24, of smaller diameter D1, and the filter holes 21 of the outer member 26, of smaller diameter D2.
• the through holes 21, 38 are made via laser technology which gives them a conical shape.
• the holes 21 of the outer limb made by laser technology have two different diameters D2e and D2s at their two ends on the inner wall 28 and on the outer wall 30.
• D2e is the input diameter
• D2s is the outlet diameter in the direction of flow of the fuel inside the outer member 26.
• the holes 21 have a divergent shape, that is to say that in the direction of fuel flow the holes have a diameter of D2e input smaller than the output diameter D2s.
• the inlet diameter D2e is proximal to the annular space E corresponding to the opening diameter of the hole 21 in the inner wall of the outer member.
• the holes 38 of the inner member also made by laser technology have two different diameters Dle and Dls at their two ends on the inner wall 37 and on the outer wall 39.
• Die is the input diameter and Dis is the output diameter corresponding to the direction of circulation of the fuel inside the inner member 24.
• the holes 38 also have a divergent shape, that is to say that in the direction of fuel circulation the holes have an input diameter Die smaller than the output diameter Dis.
• the outlet diameter Dis is proximal to the annular space E corresponding to the opening diameter of the hole 38 in the outer wall of the inner member.
• the holes 21 of the outer member 26 extend along an axis Y1 and the holes 38 of the inner member 24 extend along an axis Y2.
• the holes being made all around the filtering part, the corresponding axes Y1, Y2, are perpendicular and radial, or transverse, to the longitudinal axis X of the filter.
• each hole corresponds to its own axis Y1, Y2, the axes forming part of a radiating network.
• Other shapes of holes 21, 38 can be obtained such as for example cylindrical holes of constant diameter D1 or, convergent holes, in contrast to diverging, input diameter larger than the output diameters.
• the shape of the holes 21 is generally conical because of the peak power of the laser beam used for drilling, which explains the difference in the diameters at the two ends of the hole, the inlet diameter of the hole being larger than the exit diameter.
• the holes of the outer member 26 and the inner member 24 may also be square holes see other forms.
• the inner member 24 is first made from a circular flat sheet, for example of constant radial thickness of 0.3 to 0.5 mm. The sheet is then deep drawn to an elongated tube shape.
• the regular network may be a network of holes distributed over a set of coaxial circles arranged at regular intervals along the cylinder represented by the filtering portion 36 of the inner member.
• the inner member 24 is pierced by rotating the inner member about its longitudinal axis.
• the inner member 24 may be stainless steel.
• c) provide a raw piece of outer member 26 without holes.
• the outer member 26 is also made from a circular flat sheet, for example of constant radial thickness of 0.3 to 0.5 mm, which is then deep drawn to an elongate tube shape.
• the regular network may for example be an array of holes distributed over a set of coaxial circles arranged at regular intervals along the cylinder represented by the filtering portion 19 of the outer member.
• the outer member 26 is pierced using laser technology by rotating the outer member 26 about its longitudinal axis X. Due to the laser beam the bottom of the hole has a smaller diameter than the inlet diameter of the piercing. filtration hole. In other cases during laser drilling, one may not have the smallest diameter of the hole at one end.
• the outer member 26 may be stainless steel.
• step e) coaxially inserting the part made in step b) in the part made in step d).
• the inner member 24 is inserted coaxially into the open end of the outer member 26.
• the inner member 24 is inserted until its spherical tip 40 comes into contact with the spherical tip 32 of the outer member 26.
• Another embodiment of Alternative realization is that the spherical tips do not touch each other.
• the through holes 38 of the inner member have two diameters Die and Dis.
• the holes shown are perfectly shaped, especially the cones, but that in fact the laser drilling induces variations in geometry and dimensional tolerances making the largest diameters, or the smallest, may not be exactly at the openings of the holes.
• the through holes 21 of the outer member 26 have two diameters D2e and D2s, D2e corresponding to the inlet diameter, which in the case of a conical hole diverge from the smallest section and D2s
• the space E has a value always positive and smaller than the smallest diameter D1 of the hole 38 of the inner member 24.
• the space E can thus block the particles that would have passed through the internal holes 38. For example, if the space E has a value of 20 micrometers, the particles which are 30 micrometers will be able to pass through the internal holes 38 and will not be able to pass the space E to reach the hole 21 of the outer member 26.
• FIG. 6 is an enlarged view projected on a plane tangential to the surface of the filtering part, the offset L being defines as follows:
• the holes are tapered tapering at one end.
• Each hole 38 of the inner member opens into the annular space E in the vicinity of a plurality of holes of the outer member.
• the axis Y1 of the hole 38 of the inner member is equidistant from the axes Y2 of the holes 21 of the outer member.
• the axis Y1 of the hole 38 of the inner member may not be equidistant from the axes Y2 of the holes 21 of the outer member, while having no
• Dis is equal to Die and D2s is equal to D2e.
• the inter-hole overlap distance G is the distance that separates the two circumferences of diameter Dis from the conical holes 38 and of diameter D2e of the conical holes 21, the distance of inter-hole overlap G being the distance between two straight lines T21 and T38 parallel to each other and tangent to the two circumferences. The two lines are transverse to the line passing through the two centers of the holes 21, 38.
• the inter-hole overlap distance G is positive.
• the inter-hole overlap distance G will be equal to zero, which means that the holes 21, 38 are tangent relative to one another without coming into contact with each other. overlap. In fact the two circumferences of the holes 21, 38 are tangent to each other.
• the conical holes 38 have the diameter Dis and the conical holes 21 have a diameter D2e.
• the fixing portion 16 whose outer diameter D16 is greater than the diameter D18 of the filtration portion 18 interferes with the diameter D22 of the inlet channel 12.
• the filter 14 is mounted tightly in the inlet channel 12. To ensure that the filter 14 will be force-fitted simply, quickly and economically, one skilled in the art will be able to verify the permissible interference between a diameter D16 of the attachment portion 16 and an inner diameter D12 of the inlet channel 12. It is also known that it is necessary to ensure the choice of materials and the operating temperature range to ensure reliable interference over time.
• the holes 21, 38 are shown in a configuration where G is the inter-hole distance between the conical holes 38 of the lower limb 24 and the conical holes 21 of the outer limb 26. In this case the distance inter-hole recovery G is zero. This indicates that the diameters Dis and D2e of the holes 21, 38 are tangent to each other.
• the inter-hole overlap distance G is negative.
• This configuration in FIG. 9, which does not form part of the invention, can let the long and thin particles and the compact particles pass through the two filtering members 24, 26 of the filter 14. The particles would then disturb the operation of the device. injection.
• the fuel enters the injector 10 through the inlet channel 12 where the filter 14 is mounted.
• the fuel passes through the filter 14 through the diameter Die of the holes 38 of the inner member 24, then leaves the member Inside 24 by the diameter Dis of the inner holes 38.
• the fuel flows in the space E and enters the outer member 26 by the diameter D2e and through the holes 21 to exit by the diameter D2s.
• the fuel then flows in the annular passage 22 to go towards the nozzle of the injector 10 located at the distal end of the inlet channel 12.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (5)

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• 2015
  • 2015-12-18 FR FR1562843A patent/FR3045733A1/fr not_active Withdrawn
• 2016
  • 2016-12-16 WO PCT/EP2016/081577 patent/WO2017103204A1/fr active Application Filing
  • 2016-12-16 CN CN201680081312.7A patent/CN108700010A/zh active Pending
  • 2016-12-16 KR KR1020187020483A patent/KR20180099731A/ko unknown
  • 2016-12-16 EP EP16823234.6A patent/EP3390806A1/de not_active Withdrawn

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