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
  • F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
  • F02M35/10—Air intakes; Induction systems
  • F02M35/10209—Fluid connections to the air intake system; their arrangement of pipes, valves or the like
  • F02M35/10222—Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission
• • 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
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/12—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems characterised by means for attaching parts of an EGR system to each other or to engine parts
• • 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
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/17—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the intake system
  • F02M26/18—Thermal insulation or heat protection

Definitions

• the invention relates to an arrangement for the connection with thermal decoupling of a downstream end section of an exhaust gas recirculation pipe with a recirculation orifice of an intake circuit of a vehicle heat engine. automobile.
• the invention relates more particularly to an arrangement for the connection with thermal decoupling of a downstream end section of an exhaust gas recirculation pipe with a recirculation orifice of an intake circuit of a heat engine. of a motor vehicle, a radial clearance being reserved between said downstream end section and a peripheral wall of the recirculation orifice, the arrangement comprising a thermal decoupling ring which is arranged around the downstream end section so as to close off the radial clearance and which is sealingly attached to the recirculation line.
• the intake manifold is generally made by molding in plastic material. Such a material is very suitable because the temperature of the intake air is low enough not to damage the plastic material.
• the recirculation line is heated by the exhaust gas to a temperature that is likely to damage the plastic material forming the manifold.
• This ring has the shape of a bell having a central orifice in which is received the downstream end edge of the recirculation pipe. Said edge of the recirculation pipe is sealingly attached directly to the ring, for example by welding.
• the ring makes it possible to center the downstream end of the recirculation pipe with respect to the recirculation orifice of the collector.
• the free end of the collector is thus arranged radially at a distance from the plastic wall of the collector.
• the ring completely closes the recirculation orifice.
• the peripheral edge of the ring is attached directly to the manifold.
• the sealing of the recirculation orifice is provided by an annular seal of elastomeric material which is interposed radially between a peripheral annular skirt of the ring and the inner wall of the recirculation orifice.
• the decoupling ring keeps the hot edge of the recirculation line away from the plastic wall of the collector. It also diffuses the heat of the recirculation pipe by forming a radiator. Thus, the skirt of the decoupling ring is cold enough not to damage the seal of elastomeric material.
• the invention proposes to solve this problem economically, without increasing the size of the arrangement, by proposing an arrangement of the type described above, characterized in that the fixing of the ring on the downstream end section is deported. upstream of the recirculation orifice.
• the ring is fixed on the pipe by means of a sleeve which concentrically wraps the downstream end section, the sleeve comprising a downstream end edge which is sealingly attached to the ring, and an upstream end edge which is sealingly attached to the recirculation line upstream of the recirculation port;
• thermal insulation layer is interposed radially between the downstream end section and the sleeve;
• the thermal insulation layer is formed by an air layer present in an annular space reserved radially between the downstream end section and the sleeve;
• the annular space communicates with the circuit
• the sleeve is fixed to the pipe by welding directly on an outer wall of the pipe;
• the sleeve is attached to the ring by welding
• the sleeve is made integrally with the ring;
• An annular sealing gasket is interposed radially between a peripheral skirt of the ring and the cylindrical wall of the recirculation orifice;
• the seal is made of an elastomeric material
• a heat conduction path is controlled from the section to the joint
• the downstream end section of the recirculation pipe is connected to a body of the pipe via a convergent pipe, the fixing of the ring on the recirculation pipe being offset upstream of the downstream end section; .
• FIG. 1 is a schematic view sui represents a powertrain of a motor vehicle equipped with an exhaust gas recirculation pipe;
• FIG. 2 is an axial sectional view which shows a downstream end section of the recirculation pipe connected to an intake manifold by means of an arrangement made according to the state of the art;
• FIG. 3 is a view similar to that of Figure 2 wherein the arrangement for the connection is made according to the teachings of the invention.
• FIG. 1 shows a power unit 10 of a motor vehicle comprising an internal combustion engine 12, for example a diesel engine. Cylinders 14 of the engine 12 are supplied with fresh air via an intake circuit 16, while the hot exhaust gases are discharged by the cylinders 14 into an exhaust circuit 18.
• an internal combustion engine 12 for example a diesel engine.
• Cylinders 14 of the engine 12 are supplied with fresh air via an intake circuit 16, while the hot exhaust gases are discharged by the cylinders 14 into an exhaust circuit 18.
• the intake circuit 16 comprises an intake manifold 20 for distributing the intake air into the various cylinders 14.
• the intake manifold 20 is made of a plastic material. Such an embodiment is advantageously inexpensive.
• the exhaust gases discharged into the exhaust circuit 18 are capable of reaching a temperature greater than 400 ° C. as a function of the operating parameters of the engine 12.
• the powertrain also features a driving
• the recirculation pipe 22 is made of a metallic material.
• FIG. 2 shows a detail view showing an arrangement for connecting the downstream end section 26 of the recirculation pipe 22 with the recirculation orifice 28 of the intake manifold 20, the arrangement being made according to the state of the art.
• the downstream end portion 26 has the shape of a cylindrical tube of axis "A" axially oriented. It has a section of dimensions smaller than those of a body 32 of the recirculation pipe 22.
• the downstream end section 26 of the pipe 22 is connected to the upstream body 32 of the pipe 22 via a convergent 30.
• the downstream end section 26 has a section smaller than that of the recirculation orifice 28 so that when the free open end of the downstream end portion 26 is inserted into the recirculation orifice 28, a set J radial is reserved between the downstream end section 26 and a peripheral wall of the recirculation orifice 28.
• the downstream end portion 26 is made of a metallic material. It is here realized come of matter with the convergent 30.
• the upstream end circular edge of the convergent 30 is sealingly attached to the downstream end edge of the pipe body 32 by welding by means of an annular weld bead 34.
• the arrangement comprising a ring 36 of thermal decoupling.
• the ring 36 thus comprises a radial flange 38 pierced at its center with a central orifice 40 having a section complementary to that of the downstream end section 26.
• the flange 38 has a peripheral contour concentric with the contour of the recirculation orifice 28.
• the ring 36 also has an axial skirt 39 which extends outwardly of the intake manifold 20 and which gives the ring 36 a bell shape.
• the free end edge of the skirt 39 is provided with an annular radial flange 42 for fixing against the radial outer face of the intake manifold.
• the free upstream end edge of the downstream section 26 is inserted into the central orifice 40 of the ring 36.
• the ring 36 is fixed in a sealed manner around the downstream section 26 by welding by means of an annular weld bead 44 arranged at the edge of the central orifice 40.
• the ring 36 and the downstream section 26 are then inserted into the recirculation orifice 28 so as to close the radial clearance "J".
• the flange 38 of the ring 36 makes it possible to center the downstream section 26 away from the peripheral wall of the recirculation orifice 28 to avoid any direct contact between the downstream section 26 heated by the exhaust gases and the plastic wall. of the collector 20.
• An annular seal 46 of elastomeric material is interposed radially between the peripheral skirt 39 and the cylindrical wall of the recirculation orifice 28 to prevent any leakage of air or exhaust gas.
• the ring 36 is fixed by its flange 42 against the external face of the collector 20.
• the heat accumulated in the downstream section 26 is transmitted by conduction to the ring 36 via the bead 44 of welding.
• the flange 38 plays the role of a radiator that allows to evacuate some of this heat before it reaches the skirt 39 and the flange 42. This normally preserves the gasket 46 and the wall. collector plastic 20.
• the ring 36 is no longer sufficient to remove the heat and there is a degradation by heating the seal 46 and the plastic wall of the manifold 20.
• the invention proposes to deport the attachment 44 of the recirculation orifice upstream of the recirculation orifice 28, or upstream of the downstream end section 26, in order to increase the distance. that the The heat must pass by conduction to reach the seal 46 and the wall of the collector 20.
• FIG. 3 An example of an arrangement made according to the teachings of the invention is shown in FIG. 3.
• the ring 36 is fixed on the recirculation pipe 22 via a sleeve 48 which is open at its two axial ends. and which concentrically envelops the downstream end portion 26.
• the sleeve 48 has an internal section of dimensions greater than those of the external section of the downstream section 26 so that a space 50 is reserved radially between the downstream section 26 and the sleeve 48.
• the sleeve 48 is here made of a metallic material.
• the sleeve 48 is fixed upstream of the downstream section 26 so as to increase sufficiently the distance that the heat must travel by conduction to avoid any degradation of the seal 46 and the collector 20.
• the sleeve 48 is more particularly fixed in an upstream portion of the convergent 30.
• the sleeve 48 has an upstream section 52 which envelops the convergent 30 with reservation of a radial space 50, and a downstream section 54 which has the shape a tube which envelops the downstream section 26.
• the sleeve 48 extends axially from the upstream edge of the convergent 30 to the flange 38 of the ring 36.
• the downstream end circular edge 56 of the sleeve 38 has a smaller dimension than that of the recirculation orifice 28. in such a way that a radial clearance "J" is reserved when it is inserted into said orifice 28.
• the central orifice 40 of the ring 36 is here modified so as to receive, in an adjusted manner, the free downstream end of the sleeve 48.
• the circular edge 56 The downstream end of the sleeve 48 is sealingly attached directly to the ring 36 by welding by means of a weld bead 58.
• the ring and the sleeve are made of material.
• the upstream end edge of the sleeve 48 is fitted around the upstream upstream end of the convergent 30 to which it is directly sealingly attached by welding by means of a welding bead 44.
• Said weld bead 44 forms the offset fastening of the ring 36 on the recirculation pipe 22.
• the space 50 reserved between the sleeve 48 and the downstream section 26 forms a thermally insulating air layer 26 of the downstream end portion and the sleeve 48 downstream of the weld bead 44. Since the sleeve 48 is open downstream, the annular space 50 communicates with the interior of the manifold 20. Thus, the sleeve 48 is in contact with the pipe 22, including the downstream end section 26, only by the 44 welding cord.
• the heat accumulated in the downstream section 26 is conducted by conduction up to the skirt 39 of the ring 36 by passing successively by the weld bead 44, then by the sleeve 48 and finally by the weld bead 58 to reach the flange 38.
• the length of the conduction path of the heat accumulated in the section 26 to the flange 38 is thus controlled and the length of said path is lengthened compared to the state of the art.
• the exposed surface of the sleeve 48 in the open air allows in particular to evacuate a large amount of heat radiation and convection. The temperature thus decreases along the sleeve 48 from the section 26 to the flange 38 of sufficient to prevent degradation of the elastomeric seal 46 and the plastic manifold.
• the arrangement is very advantageous because it makes it possible to keep the collector 20 made of plastic material and the seal 46 of elastomeric material even when the temperature or the flow rate of the exhaust gases become very high.
• this arrangement makes it possible to moderate the temperature at the periphery of the ring 36 by adding only a sleeve 48 with respect to an arrangement of the state of the art.
• the arrangement is thus very compact.
• the arrangement made according to the teachings of the invention can be advantageously as compact as the arrangement made according to the state of the art by slightly decreasing the diameter of the downstream end section.
• the ring already used in the arrangement according to the state of the art can be reused as is to achieve the arrangement according to the invention, as can be seen by comparing Figures 2 and 3.
• the arrangement according to the invention thus does not require changing the design of the collector or the environment in which it is implanted.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust-Gas Circulating Devices (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=48044882

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (7)

Family Cites Families (1)

• 2013
  • 2013-01-23 FR FR1350570A patent/FR3001262A1/fr active Pending
• 2014
  • 2014-01-20 WO PCT/FR2014/050096 patent/WO2014114865A1/fr active Application Filing
  • 2014-01-20 EP EP14705829.1A patent/EP2948671B1/de active Active

Patent Citations (7)

Non-Patent Citations (1)

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