Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
  • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
  • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
  • F01N3/2013—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features
  • F01N13/18—Construction facilitating manufacture, assembly, or disassembly
  • F01N13/1872—Construction facilitating manufacture, assembly, or disassembly the assembly using stamp-formed parts or otherwise deformed sheet-metal
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
  • F01N3/2882—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
  • F01N2240/16—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an electric heater, i.e. a resistance heater
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2530/00—Selection of materials for tubes, chambers or housings
  • F01N2530/02—Corrosion resistive metals
  • F01N2530/04—Steel alloys, e.g. stainless steel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2530/00—Selection of materials for tubes, chambers or housings
  • F01N2530/06—Aluminium or alloys thereof
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• TITLE Heater for a gas purification device
• the present invention relates to a heater for a vehicle exhaust gas purification device.
• the exhaust lines of vehicles equipped with heat engines typically include catalytic purification units, for example converting NOx, CO and hydrocarbons into N2, C02 and H20.
• catalytic purification units for example converting NOx, CO and hydrocarbons into N2, C02 and H20.
• Such organs are only effective when the catalytic material is at a minimum temperature.
• purification devices have been developed incorporating a heating member mounted opposite the upstream face of a purification member, so as to heat the purification member in an accelerated manner when starting the vehicle.
• FR 3,065,027 A1 describes such a purification device, in which the heating member is formed by a plurality of intersecting heating wires mounted between a peripheral frame and a central support.
• the existing heaters are not entirely satisfactory. Indeed, the increase in temperature of the heating grid causes radial thermal expansion which can cause crushing of the strands, which can cause short circuits creating hot spots. Such hot spots cause significant fragility which can cause the heating grid to break.
• an object of the invention is to increase the durability and performance of such heaters.
• the invention relates to a heating member for a device for purifying the exhaust gas of a vehicle comprising: an outer peripheral frame, electrically conductive, having a geometric and symmetrical center about an axis, an electrically conductive central support, centered on the geometric center, and a perforated heating grid, centered on the geometric center, the heating grid extending between the central support and the outer peripheral frame, the heating grid being formed of a plurality of strands connected by knots, the strands defining between them openings.
• the heating member also has one or more of the following characteristics, taken in isolation or in any technically possible combination (s): - the heating grid has a first face and a second face, the first face and the second face each having at least one flat area, the heating grid being deformed, preferably by stamping, so as to form a relief having a centered annular shape on the geometric center, the relief projecting relative to the flat zone of the first face and defining a hollow relative to the flat zone of the second face;
• the relief has a height between one fifteenth and one fifth of the radius of the heating grid, preferably between one twelfth and one eighth of the radius of the heating grid and advantageously substantially equal to one tenth of the radius of the heating grid;
• the heating grid forms two successive annular reliefs in the radial direction, the reliefs having opposite concavities;
• the heating grid is formed of a plurality of elongated heating elements, the elongated heating elements occupying a respective angular section of the heating grid, and being arranged in zigzag inside this angular section so as to form a succession of strands connected by nodes and being linked by said nodes to the elongate heating elements occupying the adjacent angular sections, and a plurality of outer connection branches connecting the elongated heating elements to the outer peripheral frame, each outer connection branch being suitable for deforming to absorb the radial thermal expansion of the heating grid during operation of the heater;
• each external connection branch forms a lever arm.
• each external connection branch comprises a connection portion to a node, an elongated portion and a connection portion to the outer peripheral frame, the connection portions extending substantially radially, the elongated portion extending in a direction of compensation, the compensation direction forming a compensation angle with the radial direction, the compensation angle being between 10 ° and 120 °;
• the heating member comprises an electrically conductive separation ring centered on the geometric center, the heating grid having a first mesh of strands between the separation ring and the outer peripheral frame and a second mesh of strands between the separation ring and the central support, the heating grid comprising in each mesh of strands, a plurality of elongated heating elements;
• the heating grid comprises, for the first mesh of strands, a plurality of outer connection branches connecting the elongated heating elements to the outer peripheral frame and a plurality of inner connection branches connecting the elongated heating elements to the separation ring and the grid heater comprising, for the second mesh of strands, a plurality of outer connection branches connecting the elongated heating elements to the separation ring and a plurality of inner connection branches connecting the elongated heating elements to the central support;
• the number of elongated heating elements per angular sector is greater in the first mesh than in the second mesh;
• the separation crown has a width strictly greater than twice the width of a strand
• the heating grid has a structure adapted to avoid contact between the nodes during the operation of the heater
• the heating grid is adapted to deform along the axis, so as to absorb part of the radial thermal expansion of the heating grid during the operation of the heater;
• the heater comprises different elements of the strands, adapted to absorb part of the radial thermal expansion of the heating grid during the operation of the heater;
• connection portion to the outer peripheral frame of an external connection branch extends in the same direction as the connection portion to a node of the neighboring external connection branch.
• the subject of the invention is also a device for purifying the exhaust gases of an internal combustion engine comprising at least one heater as defined above.
• the subject of the invention is also a combustion engine exhaust line, comprising a gas purification device as defined above.
• the subject of the invention is also a vehicle characterized in that it comprises an exhaust line as defined above.
• FIG. 1 is a simplified schematic representation of a motor vehicle exhaust line incorporating a heater according to the invention
• FIG 2 is a perspective view of part of an exhaust line purification device of Figure 1, the outer wall of which has been shown partially cut away so as to leave visible the interior the device,
• Figure 3 is a perspective view of a portion of the heater in a first embodiment of the invention
• Figure 4 is a plan view of a heater in a second embodiment of the invention.
• Figure 5 is a plan view of a detail marked V in Figure 4.
• the exhaust line 1 shown in Figure 1 is intended to be installed on board a vehicle, typically a vehicle equipped with a heat engine 3.
• This vehicle is typically a motor vehicle, for example a car or a vehicle. truck.
• the exhaust line 1 comprises a manifold 5 capturing the exhaust gases leaving the combustion chambers of the heat engine 3, and a cannula 7 allowing the release of the exhaust gases into the atmosphere.
• the exhaust line 1 also comprises a device 9 for purifying the exhaust gases, fluidly interposed between the manifold 5 and the cannula 7, so that the exhaust gases reaching the cannula 7 have been purified by said device. purification 9.
• This purification device 9 comprises at least one member 10 for purifying the exhaust gases having an upstream face 12 through which the exhaust gases enter the purification member 10, and a downstream face 14 through which the exhaust gases. exhaust exit from the purification unit 10.
• upstream and downstream are understood in relation to the normal flow direction of the exhaust gases in the exhaust line 1.
• the purification member 10 is, for example, an SCR catalyst, a three-way catalyst, an oxidation catalyst, an SCRF particulate filter, or a NOx trap. It has an axis of symmetry (not shown).
• the purification device 9 also comprises a sheath 16 inside which the purification member 10 is placed, and a holding sheet 18 interposed between the purification member 10 and the sheath 16.
• the purification device 9 further comprises a supply member 20, for supplying the purification member 10 with the exhaust gases coming from the manifold 5, and a collecting member 22, for collecting the exhaust gases purified exiting the purification organ 10 and directing them to the cannula 7.
• the feed member 20 is typically constituted by an inlet cone or by a mixer. It is fluidly interposed between the manifold 5 and the purification member 10, and includes an exhaust gas inlet 24 fluidly connected to the manifold 5.
• the collection member 22 is typically constituted by an outlet cone. It is fluidly interposed between the purification member 10 and the cannula 7, and comprises an exhaust gas outlet 26 fluidly connected to the cannula 7.
• the supply member 20 more particularly comprises a casing 28 of electrically conductive material, delimiting a passage for the exhaust gases, and a heating member 30 housed in the casing 28.
• the supply member 20 comprises also an electrical supply 32 with a first terminal 33A and a second terminal 33B for supplying the heating member 30 with electricity.
• the casing 28 is electrically connected to the first terminal 33A of the power supply 32, typically by means of an electrical connection formed by a threaded rod welded to the casing 28. As a variant (not shown), the casing 28 is electrically connected to ground using the same type of electrical connection.
• the casing 28 has an upstream face 34 through which the exhaust gases enter the supply member 20, and a downstream face 36 through which the exhaust gases leave the member. supply 20.
• the casing 28 is adapted to guide the gases entering through the upstream face 34 to the downstream face 36.
• the supply member 20 is arranged relative to the purification member 10 so that the downstream face 36 of the casing 28 substantially coincides with the upstream face 12 of the purification member 10.
• the casing 28 constitutes a structural part adapted to withstand the mechanical stresses specific to an exhaust line without deforming.
• the casing 28 is fixed to the sleeve 16, typically by welding, riveting or screwing.
• the envelope 28 is tubular.
• the downstream face 36 of the casing 28 is centered on an axis C substantially coincident with the axis of symmetry of the purification member 10.
• the section of the downstream face 36 is circular.
• the section of the downstream face 36 is polygonal or substantially elliptical.
• the heating member 30 is housed in the casing 28 facing the downstream face 36, slightly set back towards the inside of the supply member 20 relative to this downstream face 36
• the heating member 30 is at a distance from the downstream face 36 of between 1 and 50 mm.
• the heating member 30 is thus placed opposite and at a distance from the upstream face 12 of the purification member 10.
• the heater 30 is substantially planar, that is to say it has an axial thickness less than 20%, and preferably less than 10% of its radial diameter.
• the heater 30 comprises an outer peripheral frame 40, a central support 42 and a heating grid 44.
• the heating grid 44 is formed of a plurality of strands 46 connected by nodes 48, the strands 46 delimiting between them openings 50.
• the heater 30 is made of a conductive material. It is preferably formed in one piece.
• the heater 30 is connected to the power supply 32, so that the power supply 32 is capable of passing a current through the strands 46.
• the conductive material is for example chosen from Iron-Chromium-Aluminum
• the material is Kanthal® A1, Nichrome® 80 or Nikrothal® 80.
• the heater 30 is typically made by cutting a sheet of conductive material. This cutting is for example carried out by laser, by fine-blanking, by chemical cutting, or by any other means making it possible to create orifices in the plate.
• the heater 30 is produced by additive manufacturing, in particular by three-dimensional printing.
• the heating grid 44 of the heater 30 is woven from threads of conductive material.
• the heater 30 is self-supporting.
• the outer peripheral frame 40 is electrically conductive.
• the outer peripheral frame 40 has a geometric center G and is symmetrical about a central axis X.
• the outer peripheral frame 40 has a closed contour.
• the term “thickness” of a member is used to refer to the dimension of this member in a direction parallel to the direction of circulation of the flow of exhaust gas through the heating grid 44, that is to say perpendicular. in the plane of the heating member 30, and the term “width” of a member is used to denote the smallest dimension of this next member in the plane of the heating member 30, that is to say in a plane perpendicular to the direction of circulation of the flow of exhaust gas through the heating grid 44.
• the outer peripheral frame 40 and the central support 42 their width is measured in a radial direction passing through the geometric center G.
• the outer peripheral frame 40 has for example a width greater than or equal to twice the width of each strand 46.
• the outer peripheral frame 40 serves as a fixing ring.
• the outer peripheral frame 40 is welded, brazed or force-fitted into the casing 28 so as to be in contact with the casing 28 at its outer periphery.
• the outer peripheral frame 40 is substantially at the same electrical potential as the casing 28.
• the geometric center G is substantially aligned with the C axis, that is to say that the geometric center G is at a distance from the C axis of less than 10 mm, preferably less than 5 mm.
• the central support 42 is centered on the geometric center G.
• the central support 42 is symmetrical about the central axis X.
• the central support 42 is electrically conductive.
• the central support 42 has for example a width greater than or equal to twice the width of each strand 46.
• the central support 42 has a diameter less than 20% of the diameter of the outer peripheral frame 40.
• the central support 42 is, for example, constituted by a washer of conductive material, centered on the geometric center G.
• the washer is solid, with the exception of a through hole formed in its center.
• the central support 42 contains cutouts.
• the central support 42 is electrically connected to the second terminal 33B of the power supply 32 by an electrode 70 extending through the casing 28 while being electrically insulated. of this last.
• the central support 42 is in particular linked to said electrode 70 by screwing, welding, brazing, or any other suitable means.
• Electrode 70 is rigidly attached to shell 28.
• the heating grid 44 is a perforated heating grid.
• the heating grid 44 has a geometric shape defined around the geometric center G.
• the heating grid 44 has a circular outer contour.
• the heating grid 44 extends between the central support 42 and the outer peripheral frame 40.
• the heating grid 44 is self-supporting.
• the heating grid 44 is a single material. It is made of a conductive material. In particular, it is integral with the outer peripheral frame 40 and the central support 42.
• the heating grid 44 has a first face 52 and a second face 54.
• the first face 52 is for example a downstream face
• the second face 54 is for example an upstream face.
• the first face 52 and the second face 54 are parallel to each other.
• first face 52 and the second face 54 each have at least one flat zone.
• the strands 46 do not overlap.
• the heating grid 44 has a thickness, measured between its first face 52 and its second face 54, which is substantially constant, and preferably constant. It advantageously has a thickness substantially equal to the thickness of the outer peripheral frame 40 and that of the central support 42.
• the heating grid 44 has, for example, a thickness of between 0.05 and 2 mm, preferably between 0.1 and 0.5 mm.
• the strands 46 have, between the nodes 48, the same width. Note that, on each strand 46, the smallest dimension is thickness, the largest dimension is length, and the third dimension is width.
• each node 48 has a first dimension, in a first radial direction defined from said geometric center G and separating the node 48 into two parts of equal sections, and a second dimension in a second direction perpendicular to the first radial direction, such as the first dimension and / or the second dimension is greater than twice the width of each strand 46.
• Each opening 50 is delimited by a contour having no angular point.
• the cutting of the heating member 30 is made so as to form only curves, without angular point.
• the openings 50 have the general shape of a quadrilateral, preferably a diamond, having a height defined along a radial direction starting from the geometric center G, and a width following an arc of a circle perpendicular to this radial direction.
• the width of each opening 50 is greater than its height.
• the height of each opening 50 is greater than its width.
• the width and height of each opening are equal.
• the sensitive curves to which it is necessary to pay attention not to form an angular point, are formed by the rounded corners of the openings 50.
• first rounded corners the rounded corners defined over the width of each opening are referred to as “first rounded corners”, and the rounded corners defined over the height of each opening are referred to as “second rounded corners”.
• the radii of curvature in the first and second rounded corners are chosen depending on the appearance chosen for the heating grid 44. For example, these radii of curvature are greater than half the width of each strand 46.
• the strands 46 all have a constant thickness, over their entire length. This characteristic ensures a homogeneous circulation of the electric current along each strand 46, without creating a hot spot.
• Each opening 50 has a recess at each of its second rounded corners. This recess results in an inversion of the radius of curvature of the contour of the opening between the interior of the recess and the exterior of the recess. More particularly, the recess is formed by a fillet connecting the contours of two strands 46 delimiting the opening 50, this fillet being tangential to each of these two contours.
• the heating grid 44 is formed of a plurality of elongated heating elements 56.
• each elongated heater 56 has a first end 62 and a second end 64 opposite to each other.
• the first end 62 is linked to the outer peripheral frame 40, and the second end 64 is linked to the central support 42.
• the first end 62 is electrically connected to the first terminal 33A of the power supply 32, and the second end 64 is electrically connected to the second terminal 33B of the power supply 32. There is therefore, when the power supply 32 is active, an electric potential difference between the first end 62 and the second end 64 of each elongated heating element 56. This electric potential difference is a function of the potential difference between the terminals 33A, 33B of the power supply 32.
• the elongated heating elements 56 occupy a respective angular section 66 of the heating grid 44 around the geometric center G.
• This angular section 66 is defined between a first radius 68 and a second radius 70 each extending from the second end 64 to the first end 62.
• each angular section 66 occupied by an elongated heating element 56 is interposed between a first and a second neighboring angular sections 66 each occupied by a respective elongated heating element 56, the first radius 68 of said angular section 66 coinciding with the second radius 70 of the first neighboring angular section 66, and the second radius 70 of said angular section 66 coinciding with the first radius 68 of the second neighboring angular section 66.
• Each elongated heating element 56 is formed from the meeting of several of the strands 46 described above and is arranged in zigzag inside the angular section 66 which it occupies so as to form a succession of strands 46 connected by nodes 48
• the elongated heating elements 56 are linked by said nodes 48 to the elongated heating elements 56 occupying the adjacent angular sections 66.
• Each strand 46 extends from the first ray 68 to the second ray 70.
• the strands 46 of an elongated heating element 56 are regularly distributed angularly on the heating grid 44.
• the distribution of the strands 46 of an elongated heating element 56 is for example at a constant pitch.
• the distance between two successive strands 46 measured in a radial direction is called “pitch”.
• the distribution of the strands 46 has a variable pitch.
• All of the nodes 48 are arranged on a plurality of closed contour L isopotential lines. Two of these lines are shown in Figure 3.
• the isopotential lines L are substantially centered on the geometric center G.
• the isopotential lines L all have an increasing mean diameter when the electric potential decreases.
• the temperature of the heating grid 44 increases.
• the temperature of the heating grid 44 goes from the ambient temperature in the heating element 30, ie about 30 ° or 50 °, to 1000 ° C.
• This temperature rise causes a radial thermal expansion of the heating grid 44.
• the radial thermal expansion for example causes a displacement of the order of 0.5 mm of the nodes 48 in the radial direction.
• the heating grid 44 has a structure adapted to prevent the aforementioned thermal expansion from causing contact between the nodes 48 during the operation of the heater 30.
• the heating grid 44 here comprises a plurality of outer connection branches 58 connecting the elongated heating elements 56 to the outer peripheral frame 40.
• the first end 62 of each elongated heating element 56 is linked to a connection branch. external 58.
• FIG. 3 ten external connection branches 58 are shown.
• Each outer connection branch 58 connects a node 48 between two adjacent elongated heating elements 56 to the outer peripheral frame 40.
• the outer connection branches 58 are different elements from the strands 46 and are adapted to absorb part of the radial thermal expansion of the heating grid 44 during the operation of the heater 30. .
• each external connection branch 58 is able to deform to absorb the radial thermal expansion of the heating grid 44 during operation of the heating grid. the heater 30.
• each outer connection branch 58 forms a lever arm for this purpose.
• Each outer connection branch 58 comprises a connection portion 72 to a node 48, an elongated portion 74 and a connection portion 76 to the outer peripheral frame 40.
• the connection portions 72, 76 extend substantially in a radial direction Dr.
• the elongated portion 74 extends in a direction of compensation D.
• the direction of compensation D forms a compensation angle ⁇ with the radial direction Dr.
• the compensation angle a is between 10 ° and 120 °, preferably between 20 ° and 90 °, still more preferably between 40 ° and 70 °, and ideally between 45 ° and 60 °.
• the connection portion 76 to the outer peripheral frame 40 of an outer connection branch 58 extends in the same radial direction as the connection portion 72 to a node 48 of the neighboring external connection 58.
• each connection portion 76 to the outer peripheral frame 40, belonging to a first outer connection branch 58 extends in the extension of a connection portion 72 to a node 48 belonging to a second outer connection branch 58 .
• connection portion 72 to a node 48 of an outer connection branch 58 and the connection portion 76 to the outer peripheral frame 40 of the neighboring outer connection branch 58 are not opposite each other. on the other in order to limit the risk of touching the connection portion 76 of the neighboring external connection branch 58 during the movement of the connection portion 72 at a node 48 towards the external peripheral frame 40.
• the structure of the outer connection branches 58 is such that the resultant of the expansion forces bends each outer connection branch 58, so as to rotate the elongated portion 74 by an angle less than the compensation angle a.
• the outer connection branch 58 then acts as a spring and avoids contact between the strands 46 or between the nodes 48.
• Such external connection branches 58 forming a lever arm provide a certain elasticity at the periphery of the heating grid 44. They make it possible to compensate for radial thermal expansions by ensuring radial flexibility capable of absorbing the expansion at the periphery of the heating grid 44.
• the heating grid 44 is, moreover, adapted to deform along the X axis, so as to absorb part of the radial thermal expansion of the heating grid 44 during operation of the heating grid. the heater 30.
• the heating grid 44 here has a relief 80.
• the heating grid 44 is, in particular, deformed so as to form the relief 80.
• the relief 80 has an annular shape centered on the geometric center G.
• the relief 80 protrudes from the flat area of the first face 52 and defines a hollow relative to the flat zone of the second face 54.
• the relief 80 has a height H, measured in a direction parallel to the X axis, between one fifteenth and one fifth of the radius of the heating grid 44, preferably between one twelfth and one eighth of the radius of the heating grid 44 and advantageously approximately equal to one tenth of the radius of the heating grid 44.
• the height H of the relief is 5 mm for a heating grid 44 with a radius of 50 mm.
• Such a relief 80 makes it possible to stiffen the heating grid 44 along the X axis while increasing the radial flexibility of the heating grid 44 so as to compensate for part of the radial thermal expansions.
• the relief 80 is produced, for example, by stamping the heating grid 44.
• Such a relief 80 deformed in the axial direction X makes it possible to compensate for radial thermal expansions.
• the position of the relief 80 makes it possible to control the initiation of thermal expansion by the fold created.
• the heating grid 44 forms two successive annular reliefs 80 in the radial direction, the reliefs 80 having opposite concavities.
• the reliefs 80 thus form, together, a corrugation profile.
• Each relief 80 has for example a height measured in a direction parallel to the X axis, between one fifteenth and one fifth of the radius of the heating grid 44, preferably between one twelfth and one eighth of the radius of the heating grid 44 and advantageously substantially equal to one tenth of the radius of the heating grid 44.
• the relief 80 and the external connection branches 58 are solutions that can be used independently. Each of these solutions contributes to improving the behavior of the heater 30 by improving the radial flexibility of the heating grid 44 and thus helping to absorb the thermal expansion of the heater 30.
• the first end 62 is indirectly linked to the outer peripheral frame 40 by the outer connection branch.
• the first end 62 is directly linked to the outer peripheral frame 40.
• the electrical supply 32 comprises a source 90 of electrical energy, constituted for example by the electric battery of the vehicle, or by a supercapacitor device.
• the source of electrical energy 90 is typically adapted to supply a direct or chopped current, at a voltage depending on the vehicle (12, 48 or 400 volts for example).
• the power supply 32 also includes a controller 93 arranged to control the supply of electrical energy to the heater 30.
• the controller 93 comprises, for example, an information processing unit formed of a processor and a memory associated with the processor.
• the controller 93 is produced in the form of programmable logic components, such as FPGAs (Field-Programmable Gâte Array), or in the form of dedicated integrated circuits, such as ASICs (Application-Specific Integrated Circuit).
• the controller 93 is configured in particular to choose the voltage and the electric current supplied by the power supply 32 to the heater 30, so as to maintain the heating power and / or the electric power consumed within a determined range.
• Controller 93 controls the heating by Pulse Width Modulation (PWM).
• PWM Pulse Width Modulation
• the power supply 32 also includes a member 94 for acquiring the intensity of the electric current supplying the elongated heating elements 56 and the electric voltage at the terminals of the elongated heating elements 56.
• This member 94 is of any suitable type.
• the acquisition unit 94 includes a sensor 95 for measuring electric current and a sensor 97 for measuring electric voltage.
• the electric current strength and the electric voltage are obtained by calculation, from information retrieved in controller 93.
• the controller 93 is advantageously configured to control the temperature of the elongated heating elements 56, to monitor the good working condition of the elongated heating elements 56 or of the exterior or interior connection branches, to determine the temperature of the exhaust gases when the heater element 30 is no longer used to heat the purifier 10, and to determine the flow of exhaust gas through the purifier 10, once the heater 30 is no longer used to heat the gas.
• purification unit 10 the controller 93 is for example configured to implement the control programs described in the document FR 3 065 027 A1.
• the heating member 100 comprises a separation ring 102 and the heating grid 44 has a first mesh 104 of strands 46 between the separation ring 102 and the outer peripheral frame 40 and a second mesh 106 of strands 46 between the separation ring 102 and the central support 42.
• the separation ring 102 is electrically conductive.
• the separation crown 102 is centered on the geometric center G.
• the separation crown 102 has an outer contour and an inner contour.
• the term “width” is used to refer to the distance between the outer contour and the inner contour measured perpendicular to the direction of flow of the flow of exhaust gas through the heating grid 44, that is to say in the plane of the heater 30.
• the separation crown 102 is solid between the outer contour and the inner contour.
• the separation crown 102 has a width strictly greater than twice the width of a strand 46.
• the heating grid 44 comprises in each mesh of strands 104, 106, a plurality of elongated heating elements 56 as described for the first embodiment.
• the grid 44 comprises, for the first mesh of strands 104, a plurality of outer connection branches 108 connecting the heating elements 56 to the outer peripheral frame 40 and a plurality of inner connection branches 110 connecting the heating elements to the separation crown 102.
• the grid 44 comprises, for the second mesh of strands 106, a plurality of external connection branches 1 12 connecting the heating elements 56 to the separation ring 102 and a plurality of internal connection branches 1 14 connecting the heating elements. 56 to the central support 42.
• the number of elongated heating elements 56 is greater in the first mesh 104 than in the second mesh 106.
• the number of angular sections 66 is greater in the first mesh 104 than in the second mesh 106.
• the number of elongated heating elements 56 per angular sector is greater in the first mesh 104 than in the second mesh 106.
• the second mesh 106 thus appears denser than the first mesh 104.
• the second mesh 106 comprises twenty elongated heating elements 56 for 360 ° and the first mesh 104 comprises eighty elongated heating elements 56 for 360 °.
• the first mesh 104 thus comprises four times more elongated heating elements 56 than the second mesh 106.
• the first mesh 104 includes twice as many elongated heating elements 56 as the second mesh 106.
• the first mesh 104 comprises N times more elongated heating elements 56 than the second mesh 106, N being an integer strictly greater than 1.
• Such a structure allows for several stages of different resistances. This allows the electrical resistance of the heating grid 44 and the exchange surface to be adjusted by varying the diameter of the separation ring 102. In addition, this allows for more design freedom. Finally, the structure improves the mechanical strength of the heating grid 44 by stiffening it.
• this makes it possible to adjust or adjust the electrical resistance according to the desired supply voltage in order to have good mechanical resistance and a suitable temperature profile.
• the heater 100 comprises several concentric separation rings 102, the heating grid 44 further defining a different mesh between each separation ring 102.
• the invention described above it is thus possible to obtain a heating member 30, 100 having good mechanical strength.
• the mechanical strength obtained or the dissipation of radial thermal expansion makes it possible to avoid the appearance of hot spots which would have the consequence of locally weakening the heater 30, 100, to the point of risking its rupture.
• the heating grid 44 of the heater 100 according to the second embodiment comprises a relief 80, as described for the first embodiment.
• the elongated heating elements 56 of the first mesh 104 are connected to the outer peripheral frame 40 and / or the elongated heating elements 56 of the second mesh 106 are connected to the separation ring 102 by outer connection branches. 58 as described for the first embodiment.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Exhaust Gas After Treatment (AREA)
• Resistance Heating (AREA)

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• 2019
  • 2019-03-20 FR FR1902865A patent/FR3094040B1/fr not_active Expired - Fee Related
• 2020
  • 2020-03-18 WO PCT/EP2020/057372 patent/WO2020187957A1/fr not_active Ceased
  • 2020-03-18 US US17/439,027 patent/US11674420B2/en active Active
  • 2020-03-18 EP EP20710551.1A patent/EP3942164A1/de not_active Withdrawn
  • 2020-03-18 CN CN202080022685.3A patent/CN113614340B/zh not_active Expired - Fee Related
  • 2020-03-18 KR KR1020217030017A patent/KR20210126119A/ko not_active Abandoned

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