Exhaust gas purification device with improved air inlet nozzle

Abstract

The invention relates to an exhaust gas purification device with an improved air inlet nozzle. An end piece (20) is intended to equip an exhaust gas purification device (10), in particular for an internal combustion engine, with an air inlet nozzle (18). The end piece (20) comprises a lateral wall (19) having a substantially rotational shape and at least one first air outlet port (24) arranged in the lateral wall (19).

Description

Technical Field

[0001] This invention relates to the field of exhaust gas purification devices, particularly for internal combustion engines. Such purification devices are intended for use in the exhaust lines of internal combustion engines. Background Technology

[0002] Internal combustion engines are, for example, mounted on vehicles, particularly motor vehicles, public transport vehicles or freight vehicles, ships or any other conceivable vehicle. Internal combustion engines can also be equipped with fixed mountings.

[0003] Vehicles equipped with internal combustion engines typically include catalytic converters in their exhaust systems, such as those for removing NO. x CO and hydrocarbons are converted into N2, CO2, and H2O. Such components are typically only effective when the catalytic material is at a temperature above a predetermined temperature threshold.

[0004] To address this, a purification device has been developed that includes a heating element mounted opposite the upstream surface of the purification component to accelerate the heating of the purification component when the vehicle is started.

[0005] Therefore, exhaust gas purification devices, particularly for internal combustion engines, are known from the prior art, and include:

[0006] - A shell extending along the longitudinal direction;

[0007] - The purification components housed within the casing; and

[0008] - Heating elements are placed near the purification components.

[0009] To improve this purification device, it is known how to configure the air inlet nozzle that leads into the housing to blow air into the housing, especially to avoid overheating of the heating element.

[0010] The objective of this invention is, in particular, to further improve such a purification device. Summary of the Invention

[0011] Therefore, the subject of the present invention is particularly a purification device for exhaust gas, especially for internal combustion engines, the purification device comprising a housing, a purification assembly, a heating element and an air inlet nozzle, the exhaust gas being intended to flow in the housing, the purification assembly being housed in the housing, the heating element being disposed near the purification assembly, and the air inlet nozzle extending into the housing, characterized in that the nozzle is equipped with an end member comprising a side wall having a generally rotary shape, at least one first air outlet being formed in said side wall.

[0012] An end piece positioned at the end of the air inlet nozzle is used to diffuse the air, ensuring the heating element is sprayed as evenly as possible. This both cools the heating element and distributes heat from the heating element towards the purification assembly in the most uniform manner possible. Due to this uniform diffusion, the purification assembly has no hot spots. Therefore, the lifespan of the purification assembly is increased. Furthermore, such uniform diffusion can increase the maximum acceptable power of the heating element. Consequently, the above-described conditions advantageously lead to a reduction in catalytic initiation time.

[0013] The end piece according to the invention may also include one or more of the following features, either individually or in combination of all technically conceivable elements.

[0014] - The end piece has a bottom wall located at the end of the end piece.

[0015] - The end piece has at least one second air outlet port disposed in the bottom wall.

[0016] - Each second air outlet port on the bottom wall is selected from: an air outlet port defined by a straight edge and a curved edge, the end of the curved edge being connected to the end of the straight edge; and / or an air outlet defined by two parallel long curved edges, the two parallel long curved edges being connected at their ends by two short edges; and / or a circular air outlet.

[0017] - The side walls of the end piece have a generally truncated conical shape, at least on the lower portion of the end piece.

[0018] - The end piece has an upper part and a lower part that are separated by a collar.

[0019] - The sidewalls of the end piece have an inner surface in the lower portion that has a generally rotatable shape about an axis, and the collar extends in a plane that is not perpendicular to the axis.

[0020] - The end piece includes an air inlet opening in the upper part and a conduit that widens from the air inlet opening to the lower part.

[0021] - The end piece includes an air inlet opening and an air inlet cross section, and each air outlet opening has an air outlet cross section, such that the sum of the surface areas of the air outlet cross sections is included between 20% and 200% of the surface area of ​​the air inlet cross section, preferably greater than 100%.

[0022] - The air inlet nozzle is oriented towards the heating element.

[0023] - The purification device has only one air inlet nozzle. Attached Figure Description

[0024] Various aspects and advantages of the invention will become apparent after reading the following description, given only by way of example and with reference to the accompanying drawings, in which:

[0025] Figure 1 This is a schematic diagram of a purification system according to an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 A perspective view of the end piece of the air injection nozzle of the purification device shown; and

[0027] Figure 3 yes Figure 2 The axial cross-sectional view of the end piece is shown. Detailed Implementation

[0028] Figure 1 An example of a purification device 10 according to an embodiment of the present invention is shown, which is used to equip the exhaust pipe of an internal combustion engine.

[0029] The purification device 10 is installed in the exhaust pipeline between the upstream and downstream sections. The terms "upstream" and "downstream" are based on the flow direction of the exhaust gas in the exhaust pipeline.

[0030] The purification device 10 includes a housing 12 extending along the longitudinal direction X and defining an outer shell. The housing 12 is made of, for example, a metallic material.

[0031] The housing 12 includes a central portion 12A, an inlet portion 12B, and an outlet portion 12C.

[0032] The inlet portion 12B has a closed housing on the upstream side, and the outlet portion 12C has a closed housing on the downstream side.

[0033] The inlet portion 12B has a shape that widens from the inlet pipe 13 in the upstream section to the central portion 12A. The inlet portion 12B has any shape, such as a generally truncated conical shape or a widening shape.

[0034] The purification device 10 includes a purification assembly 14 housed within a housing 12, such that exhaust gas circulating within the housing 12 passes through the purification assembly 14. The purification device 14 is, for example, a three-way catalytic converter, a diesel oxidation catalyst, an SCR catalyst, or any other suitable type. The purification assembly 14 preferably has a generally rotational shape about an axis parallel to the longitudinal direction X.

[0035] Traditionally, the purification device 10 includes a heating device, which includes a heating element 16 disposed close to the purification device 14, preferably upstream of the purification assembly 14.

[0036] The heating element 16 is housed in the housing 12. The heating element 16 is intended for use in preheating the purification device, particularly during or before engine ignition.

[0037] Advantageously, the heating element 16 has a generally rotating shape defined about an axis parallel to the longitudinal direction X.

[0038] The heating element 16 is permeable to gas and is specifically designed to allow gas (particularly exhaust gas and air, which will be described later) flowing in the longitudinal direction X to pass through, such that the gas is heated as it flows through the heating element 16.

[0039] Preferably, the heating element 16 is composed of a metal grid. In a variation, the heating element 16 may be made of metal foam or any other suitable heating element (e.g., a honeycomb structure). More specifically, the heating element 16 may be composed of any resistive element suitable for converting electric current into heat.

[0040] The heating element 16 extends over the entire channel section of the housing 12, ensuring that the gas flowing through the housing 12 necessarily flows through the heating element 16. The gas is thus heated uniformly.

[0041] Traditionally, the heating element 16 includes at least one, preferably two, electrical terminals through which the heating element 16 is intended to be powered. For this purpose, each of these electrical terminals is intended for connection to a corresponding electrode.

[0042] The purification device 10 according to the invention includes at least one air injection nozzle 18 designed for injecting air into the housing. Preferably, the purification device 10 includes only one injection nozzle 18.

[0043] The air blown by the injection nozzle 18 is particularly capable of diffusing heat energy during the preheating of the purification assembly 14 by the heating element 16.

[0044] Advantageously, the injection nozzle 18 is configured to pass through the inlet portion 12B of the housing 12.

[0045] The injection nozzle 18 is oriented along the direction of the heating element 16, meaning that the airflow injected through the injection nozzle 18 has a component along the longitudinal axis X, which is oriented from upstream to downstream in the same direction as the exhaust gas flow through the housing 12. The fact that the nozzle 18 is oriented to blow air in the same direction as the exhaust gas flow reduces the impact of the airflow on exhaust gas recirculation and prevents back pressure and thermomechanical stress from being generated on the nozzle 18. This is particularly true during the passive phase of the heating element 16 (i.e., when the engine is running normally) and even more so during the full-load phase of the engine. The purpose of this orientation is to minimize the deviation (masking) of the flow generated by the motor on the heating element 16 and on the purification assembly 14.

[0046] The injection nozzle 18 includes an end piece 20 designed to optimize the diffusion of air toward the heating element 16.

[0047] exist Figure 2 and Figure 3 The end member 20, shown in more detail, includes a side wall 19 having a generally rotary shape.

[0048] End member 20 extends along axis A. In the described example, the lateral wall 19 has a generally rotatable shape about axis A.

[0049] The end member 20 includes an upper portion 20A intended to be disposed outside the housing 12 and a lower portion 20B intended to extend inside the housing 12. Thus, the end member 20 passes through an opening 21 provided in the inlet portion 12B.

[0050] Advantageously, the end piece 20 includes a collar 22 that separates the upper portion 20A and the lower portion 20B. The collar 22 is designed to abut against the edge of the opening 21. The collar 22 provides a welded engagement between the end piece 20 and the inlet portion 12B, thereby preventing weld particles from protruding into the purification device.

[0051] The collar 22 is preferably inclined relative to axis A, that is, the collar extends in a plane that is not perpendicular to axis A. Therefore, the inclination of the collar 22 results in the orientation of the end piece 20 inside the housing 12, that is, the orientation of the lower portion 20B. Those skilled in the art who design the end piece 20 will be able to readily select the inclination of the collar 22 according to the desired orientation of the lower portion 20B.

[0052] More specifically, in the lower portion 20B, the lateral wall 19 has an inner surface 19A and an outer surface 19B. In the described example, the inner surface 19A and the outer surface 19B are concentric, both having a generally torsional shape defined about axis A. However, in a variation, only the inner surface 19A has a generally torsional shape defined about axis A, and the shape of the outer surface 19B is less important for air diffusion.

[0053] In a preferred embodiment, the end member 20 is oriented toward the central portion of the heating element 16. Axis A, for example, passes through the center of the heating element 16.

[0054] Axis A forms an angle with longitudinal axis X, for example, between 0° and 75°, preferably between 5° and 60°, and more preferably between 10° and 45°.

[0055] like Figure 2 and Figure 3 As shown, the end piece 20 includes at least one air outlet port in its lower portion 20B.

[0056] More specifically, the side wall 19 includes at least one air outlet port in the lower portion 20B, and preferably includes a plurality of air outlet ports, referred to as the first air outlet port 24.

[0057] In the described example, each first air outlet port 24 has a circular shape. However, in a variation, the first air outlet port 24 may have other possible shapes, such as elliptical, rectangular, triangular, or other shapes. Furthermore, the first air outlet ports 24 do not necessarily all have the same shape.

[0058] Advantageously, the first air outlet ports 24 are circumferentially distributed over the entire periphery of the side wall 19. Thus, air is injected in all directions through the air outlet ports 24, which allows air to reach the heating element 16 substantially uniformly.

[0059] Preferably, the first air outlet port 24 is circumferentially aligned in a plurality of rows stacked along axis A (e.g., in three rows in the described example).

[0060] In each row, for example, the distance between two adjacent first air outlets 24 is less than the diameter of each of the two first air outlets 24.

[0061] According to the described embodiment, the side wall 19 has a generally truncated conical shape, at least in the lower portion 20B. Therefore, the first air outlet port 24 is oriented in a direction not perpendicular to axis A.

[0062] It should be noted that the cone angle is preferably less than 80°.

[0063] Therefore, an extra-flat cone with an 80° angle relative to axis A can be envisioned. In this case, the axis of the first outlet port 24 is 10° relative to axis A.

[0064] According to a variation (not shown), the lower portion 20B can be cylindrical, in which case the axis of the first outlet port 24 is 90° relative to axis A.

[0065] Advantageously, the end member 20 further includes a bottom wall 26 disposed at the end portion of the end member 20.

[0066] In the described embodiment, the end member 20 includes at least one air outlet port formed in the bottom wall 26, referred to as a second air outlet port 28. In a variant, the bottom wall 26 may not include a port.

[0067] In the described example, the bottom wall 26 includes two second air outlet ports 28, which are preferably arranged radially close to the outer edge of the bottom wall 26.

[0068] One of the second air outlets 28 is defined, for example, by a straight edge and a curved edge, the end of which connects to the end of the straight edge.

[0069] One of the second air outlet ports 28 is defined, for example, by two parallel long curved edges that are connected at their ends by two short edges.

[0070] A second air outlet port 28 may also be provided in other forms, such as having circular, rectangular, triangular, elliptical edges or any conceivable form.

[0071] It should be noted that the end piece 20 includes an air inlet opening 30 connected to the nozzle 18 (in Figure 3 (See image). The air inlet opening 30 has an air inlet cross-section, and each air outlet opening 24, 28 has its own air outlet cross-section, such that the sum of the surface areas of the air outlet cross-sections is included between 20% and 200% of the surface area of ​​the air inlet cross-section.

[0072] Preferably, the sum of the surface areas of the air outlet cross-sections is greater than the surface area of ​​the air inlet cross-section. Therefore, end member 20 does not imply back pressure that hinders the flow of injected air.

[0073] Advantageously, in the upper part 20A, the end member 20 has an internal conduit that widens from the air inlet opening 30 to the lower part 20B.

[0074] Preferably, the end member 20 includes a flange 32 for securing the end member 20 to the nozzle 18.

[0075] It should be noted that the end piece 20 is manufactured, for example, by the following manufacturing method.

[0076] The manufacturing method includes making flange 32 and tube.

[0077] The method then includes deforming the tube to form a collar 22.

[0078] The tube is also preferably deformed in its lower portion to form the lower portion 20B, for example, in the form of a truncated conical shape.

[0079] The method then includes drilling out a first air outlet port 24.

[0080] Finally, the method includes engaging the flange 32 with the tube to form the end piece 20. The engagement is performed, for example, by welding.

[0081] It should be noted that the method advantageously includes fabricating a bottom wall 26 (preferably including one or more second outlet ports 28) and connecting the bottom wall 26 to the pipe, for example by welding it to the end of the pipe.

[0082] The resulting end piece 20 is directly mounted onto the purification device 10, more specifically, into the opening 21 of the inlet portion 12B, such that the collar 22 rests on the edge of the opening 21. The collar 22 is then preferably welded to said edge of the opening 21. The collar 22 provides a welded engagement of the end piece 20 on the inlet portion 12B, thereby preventing weld particles from protruding into the purification device.

[0083] In one variant, end piece 20 may be made by casting or any other conceivable method.

[0084] The end piece 20 according to the invention appears to be used to uniformly diffuse air toward the heating element 16. The air reaching the end piece 20 is distributed in multiple outlet ports, which generates turbulence in the airflow and enables good uniformity and good air velocity to be obtained on the heating element 16.

[0085] It should be noted that the present invention is not limited to the embodiments described above, but may have various supplementary variations.

Claims

1. A purification device (10) for exhaust gas, the purification device (10) comprising a housing (12), a purification assembly (14), a heating element (16), and an air inlet nozzle (18), wherein the exhaust gas is intended to flow in the housing (12), the purification assembly (14) is housed in the housing (12), the heating element (16) is disposed adjacent to the purification assembly (14), and the air inlet nozzle (18) extends into the housing (12), wherein the air inlet nozzle (18) is equipped with an end member (20), the end member (20) comprising a side wall (19) having a generally rotary shape, at least one first air outlet (24) being disposed in the side wall (19), characterized in that: - The end piece (20) has a bottom wall (26) disposed at the end portion of the end piece (20), and the end piece (20) has at least one second air outlet port (28) disposed in the bottom wall (26). - One of the second air outlet ports (28) is defined by a straight edge and a curved edge, the end of the curved edge being connected to the end of the straight edge, and - One of the second air outlet ports (28) is defined by two parallel long curved edges, which are connected at their ends by two short edges.

2. The purification device (10) according to claim 1, characterized in that Each second air outlet port (28) of the bottom wall (26) is selected from: - An air outlet port defined by a straight edge and a curved edge, wherein the end of the curved edge connects to the end of the straight edge; and / or - An air outlet defined by two parallel long edges, which are connected at their ends by two short edges, and / or - Circular air outlet port.

3. The purification device (10) according to claim 1, characterized in that The side wall (19) of the end piece (20) has a generally truncated conical shape at least on the lower portion (20B) of the end piece (20).

4. The purification device (10) according to claim 1, characterized in that The end piece (20) has an upper portion (20A) and a lower portion (20B) separated by a collar (22).

5. The purification device (10) according to claim 4, characterized in that The side wall (19) of the end piece (20) has an inner surface (19A) in the lower portion (20B) that has a generally rotating shape around the axis (A), and the collar (22) extends in a plane that is not perpendicular to the axis (A).

6. The purification device (10) according to claim 4, characterized in that The end piece (20) includes an air inlet opening (30) in the upper portion (20A) and a conduit that widens from the air inlet opening (30) to the lower portion (20B).

7. The purification device (10) according to claim 1, characterized in that The nozzle (20) includes an air inlet opening (30) having an air inlet cross section, and each air outlet port (24, 28) has an air outlet cross section, the sum of the surface areas of the air outlet cross sections (24, 28) being included between 20% and 200% of the surface area of ​​the air inlet cross section.

8. The purification device (10) according to claim 7, characterized in that The sum of the surface areas of the air outlet cross sections (24, 28) is greater than 100% of the surface area of ​​the air inlet cross section.

9. The purification device (10) according to claim 1, characterized in that The air inlet nozzle (18) is directed towards the heating element (16).

10. The purification device (10) according to claim 1, characterized in that The purification device (10) comprises only one air inlet nozzle (18).

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