Electric heater and exhaust gas aftertreatment device

Abstract

An electric heater comprises a shell, a heating band assembly, a first electrode assembly and a second electrode assembly. The heating band assembly comprises several layers of heating bands. The heating band assembly comprises an S-shaped bending part in the center of the heating band assembly, which comprises an outermost heating band, an innermost heating band and an intermediate heating band between the outermost heating band and the innermost heating band. The thickness of the outermost heating band and the thickness of the innermost heating band are both smaller than the thickness of the intermediate heating band. In this way, the problem of uneven resistance of the outermost heating band and the innermost heating band at the bending position is alleviated. In addition, the utility model also discloses a tail gas aftertreatment device comprising the electric heater.

Description

Technical Field

[0001] This utility model relates to an electric heater and an exhaust gas aftertreatment device, belonging to the field of engine exhaust gas aftertreatment technology. Background Technology

[0002] Exhaust gas aftertreatment devices in related technologies typically include at least one exhaust gas aftertreatment component. The exhaust gas aftertreatment component includes a housing and an exhaust gas aftertreatment carrier encapsulated within the housing. The exhaust gas aftertreatment carrier has an operating temperature range; that is, the exhaust gas aftertreatment carrier achieves optimal operating efficiency only when the temperature reaches this operating temperature range.

[0003] With increasingly stringent emission regulations, higher and higher requirements are being placed on exhaust aftertreatment devices, especially during engine cold starts when the exhaust gas temperature is too low to reach the operating temperature of the aftertreatment system. In this situation, the aftertreatment system may not function or its conversion efficiency may be extremely low, easily leading to emissions pollution and other problems.

[0004] Therefore, how to minimize the time required to reach the operating temperature of the exhaust gas aftertreatment carrier is a technical problem faced by those skilled in the art.

[0005] An electric heater is a device that uses electrical energy to heat exhaust gas, thereby shortening the time it takes to reach the operating temperature of the exhaust gas after-treatment carrier. It is one of the important technical means in the industry.

[0006] An electric heater typically includes a housing, a heating element, and electrodes, with the electrodes usually connected to the heating element by welding.

[0007] The heating element includes a heating strip wound into a disc shape. However, overheating is prone to occur at the bends in the heating strip, especially in the middle of the heating element where the bend radius is small, affecting the reliability of the electric heater. Utility Model Content

[0008] The purpose of this invention is to provide a highly reliable electric heater and exhaust gas aftertreatment device.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: an electric heater, comprising:

[0010] A housing, the housing including an installation space;

[0011] A heating band assembly, at least partially located in the installation space, comprises several layers of heating bands stacked and wound together to form a disc shape. The heating band assembly includes an S-shaped bend at its center, comprising an outermost heating band, an innermost heating band, and an intermediate heating band located between the outermost and innermost heating bands. The thickness of both the outermost and innermost heating bands is less than the thickness of the intermediate heating band.

[0012] A first electrode assembly, comprising a first electrode, wherein the first electrode is electrically connected to the heating band assembly;

[0013] The second electrode assembly includes a second electrode, which is electrically connected to the heating band assembly;

[0014] One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0015] As a further improvement of the present invention, the S-shaped bending portion includes a first outer bending portion located on the outermost heating band, a first inner bending portion located on the outermost heating band, a second inner bending portion located on the innermost heating band, and a second outer bending portion located on the innermost heating band; the first outer bending portion and the second inner bending portion are arranged opposite to each other.

[0016] As a further improvement of the present invention, each layer of heating band includes a wave section, a first extension section connected to one end of the wave section, and a second extension section connected to the other end of the wave section.

[0017] The electric heater also includes:

[0018] A first connecting block, the first connecting block having a plurality of first mounting slots, the first extension being at least partially received in the first mounting slots;

[0019] The second connecting block is provided with a plurality of second mounting slots, and the second extension is at least partially received in the second mounting slots.

[0020] As a further improvement of this utility model, the first electrode is connected to the first connecting block, and the second electrode is connected to the second connecting block.

[0021] As a further improvement of the present invention, the housing includes an outer surface, an inner surface opposite to the outer surface, and a first mounting hole that penetrates the outer surface and the inner surface and communicates with the mounting space.

[0022] The first connecting block is provided with a first fixing hole;

[0023] The first electrode is provided with a first fixing part, which passes through the first mounting hole and is connected to the first fixing hole by means of thread engagement.

[0024] As a further improvement of this utility model, the first fixing hole is provided with an internal thread, and the first fixing part is provided with an external thread, wherein the internal thread and the external thread cooperate.

[0025] As a further improvement of the present invention, the first connecting block is provided with a first welding groove, the opening direction of the first welding groove facing the heating belt assembly; when the first fixing part of the first electrode is connected to the first fixing hole by means of threaded engagement, the first electrode is at least partially exposed in the first welding groove.

[0026] As a further improvement of the present invention, the first welding groove is used to fill the solder to fix the first fixing part of the first electrode together with the first connecting block.

[0027] As a further improvement of the present invention, the first connecting block is made of metal material and includes a first mounting part, a first connecting part connected to the first mounting part, and a first clearance space located inside the first mounting part.

[0028] The first mounting portion includes a first surface and a second surface opposite to the first surface. The first fixing hole is disposed in the first mounting portion, and the first fixing hole passes through the first surface and the second surface and communicates with the first clearance space.

[0029] This utility model also discloses an exhaust gas aftertreatment device, which includes:

[0030] Intake components;

[0031] An electric heater located downstream of the intake assembly along the airflow direction;

[0032] A first exhaust gas aftertreatment module located downstream of the electric heater along the airflow direction;

[0033] A second exhaust gas aftertreatment module located downstream of the first exhaust gas aftertreatment module along the airflow direction;

[0034] A mixer assembly located downstream of the second exhaust gas aftertreatment module along the airflow direction;

[0035] A third exhaust gas aftertreatment module located downstream of the mixer assembly along the airflow direction; and

[0036] An exhaust assembly located downstream of the third exhaust gas aftertreatment module along the airflow direction;

[0037] The electric heater is the aforementioned electric heater.

[0038] Compared to existing technologies, the electric heater of this invention includes a heating belt assembly comprising several layers of heating belts stacked and wound together to form a disc. The heating belt assembly includes an S-shaped bend at its center, comprising an outermost heating belt, an innermost heating belt, and an intermediate heating belt located between the outermost and innermost heating belts. The thickness of both the outermost and innermost heating belts is less than the thickness of the intermediate heating belt. This design alleviates the problem of uneven resistance between the outermost and innermost heating belts at the bend, cleverly solving the overheating problem and improving reliability. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the exhaust gas aftertreatment device of this utility model.

[0040] Figure 2 This is a three-dimensional schematic diagram of the electric heater of this utility model in one embodiment.

[0041] Figure 3 yes Figure 2 A three-dimensional diagram from another angle.

[0042] Figure 4 yes Figure 2 The main view.

[0043] Figure 5 yes Figure 3 The main view.

[0044] Figure 6 yes Figure 4 A magnified view of part A within the middle frame.

[0045] Figure 7 yes Figure 4 A magnified view of part B within the middle frame.

[0046] Figure 8 yes Figure 2 The left view.

[0047] Figure 9 It is along Figure 8 A cross-sectional view of the CC line.

[0048] Figure 10 yes Figure 2 Partial exploded three-dimensional view, in which the first electrode assembly and the second electrode assembly are separated.

[0049] Figure 11 yes Figure 10 Another perspective of partial 3D exploded view.

[0050] Figure 12 yes Figure 10 A further partial exploded perspective view, wherein the first electrode assembly and the second electrode assembly are further exploded.

[0051] Figure 13 yes Figure 12 Another perspective of partial 3D exploded view.

[0052] Figure 14 yes Figure 12 Further partial exploded view, in which the shell is further disassembled.

[0053] Figure 15 yes Figure 14 Another perspective of partial 3D exploded view.

[0054] Figure 16 yes Figure 14 An improved 3D exploded view.

[0055] Figure 17 yes Figure 16 Another perspective of the exploded 3D view.

[0056] Figure 18 yes Figure 16 A 3D schematic diagram of a pin assembly.

[0057] Figure 19 yes Figure 18 A three-dimensional exploded view.

[0058] Figure 20 yes Figure 18 A three-dimensional diagram from another angle.

[0059] Figure 21 yes Figure 20 A three-dimensional exploded view.

[0060] Figure 22 It is a three-dimensional exploded view of the first connecting block, the second connecting block, the heating belt assembly, the first electrode assembly, and the second electrode assembly.

[0061] Figure 23 yes Figure 22 The main view.

[0062] Figure 24 yes Figure 22 Another perspective of the exploded 3D view.

[0063] Figure 25 yes Figure 24 The main view.

[0064] Figure 26 yes Figure 23 A magnified view of part D circled in the middle.

[0065] Figure 27 yes Figure 23 A magnified view of part E circled in the middle.

[0066] Figure 28 It is along Figure 4 A cross-sectional view of the FF line.

[0067] Figure 29 This is a perspective view of the electric heater of this utility model in another embodiment.

[0068] Figure 30 yes Figure 29 Partial exploded 3D diagram.

[0069] Figure 31 yes Figure 30 Further partial exploded view.

[0070] Figure 32 yes Figure 31 A magnified view of the circled area G.

[0071] Figure 33 It is along Figure 32 A schematic diagram of the cross section of the HH line. Detailed Implementation

[0072] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Where several specific embodiments exist, features in these embodiments can be combined with each other without conflict. When the description relates to the drawings, unless otherwise stated, the same numbers or symbols in different drawings represent the same or similar elements. The content described in the following exemplary embodiments does not represent all embodiments of this utility model; rather, they are merely examples of products consistent with this utility model and as described in the claims.

[0073] The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the scope of protection of this invention. It should be understood that terms such as "first," "second," and similar words used in the specification and claims of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish the features.

[0074] Please refer to Figure 1As shown, this utility model discloses an exhaust aftertreatment device, which includes an intake assembly 200, an electric heater 100 located downstream of the intake assembly 200 along the airflow direction, a first exhaust aftertreatment module 300 (e.g., a diesel oxidation catalyst, DOC) located downstream of the electric heater 100 along the airflow direction, a second exhaust aftertreatment module 400 (e.g., a diesel particulate filter, DPF) located downstream of the first exhaust aftertreatment module 300 along the airflow direction, a mixer assembly 500 located downstream of the second exhaust aftertreatment module 400 along the airflow direction, a urea nozzle 600 mounted on the mixer assembly 500, a third exhaust aftertreatment module 700 (e.g., a selective catalytic reduction, SCR) located downstream of the mixer assembly 500 along the airflow direction, and an exhaust assembly 800 located downstream of the third exhaust aftertreatment module 700 along the airflow direction. The first exhaust aftertreatment module 300, the second exhaust aftertreatment module 400, and the third exhaust aftertreatment module 700 are collectively referred to as exhaust aftertreatment modules. Please refer to... Figure 1 As shown, the airflow direction is Figure 1 The direction indicated by the hollow arrow.

[0075] Please combine Figures 2 to 28 As shown in the figure, the first embodiment of the present invention discloses an electric heater 100 for use in the exhaust gas aftertreatment device. The electric heater 100 includes a housing 1, a heating band assembly 2 at least partially located in the housing 1, a first electrode assembly 3 mounted on the housing 1, a second electrode assembly 4 mounted on the housing 1, a first connecting block 5 connecting one end of the heating band assembly 2 to the first electrode assembly 3, a second connecting block 6 connecting the other end of the heating band assembly 2 to the second electrode assembly 4, a support frame 7 at least partially located in the housing 1, and a plurality of pin assemblies 8 fixing the heating band assembly 2 to the support frame 7 along the axial direction of the electric heater 100.

[0076] In the embodiment illustrated in this utility model, the housing 1 is made of a metallic material, such as stainless steel. The housing 1 is generally hollow and cylindrical, and has an installation space 10. The housing 1 includes an outer surface 11 and an inner surface 12 opposite to the outer surface 11, the inner surface 12 being exposed in the installation space 10. The housing 1 also includes a first mounting hole 13 penetrating the outer surface 11 and the inner surface 12 and communicating with the installation space 10, and a second mounting hole 14 penetrating the outer surface 11 and the inner surface 12 and communicating with the installation space 10. In the embodiment illustrated in this utility model, both the first mounting hole 13 and the second mounting hole 14 are circular through holes. Of course, those skilled in the art will understand that in other embodiments of this utility model, the first mounting hole 13 and the second mounting hole 14 can also be other shapes, including but not limited to elliptical holes, oblong holes, rectangular holes, trapezoidal holes, triangular holes, etc., which will not be elaborated further in this utility model. Furthermore, in the embodiment illustrated in this utility model, both the outer surface 11 and the inner surface 12 are arc-shaped surfaces. Of course, those skilled in the art will understand that in other embodiments of this utility model, the outer surface 11 and the inner surface 12 may also be planar.

[0077] In the illustrated embodiment of this utility model, the heating band assembly 2 includes several layers of heating bands 21 made of metal material. In another illustrated embodiment, the heating band assembly 2 includes seven layers of heating bands 21, each layer comprising a wave portion 210, a first extension portion 211 connected to one end of the wave portion 210, and a second extension portion 212 connected to the other end of the wave portion 210. The wave portion 210 is generally wave-shaped, having crests and troughs. Adjacent layers of heating bands 21 are fixed together. In one embodiment of this utility model, adjacent layers of heating bands 21 are fixed together by brazing. Those skilled in the art will understand that the way adjacent layers of heating bands 21 are fixed together can be varied; for example, a crest of one heating band 21 may be fixed to a crest of an adjacent heating band 21; or a crest of one heating band 21 may be fixed to a trough of an adjacent heating band 21; or a trough of one heating band 21 may be fixed to a trough of an adjacent heating band 21. The heating belt assembly 2 includes a plurality of gap holes 22 located between two adjacent heating belts 21. Most of the gap holes 22 are used to allow exhaust gas to flow through, thereby heating the exhaust gas using the heating belt assembly 2.

[0078] Those skilled in the art will understand that the peaks of each heating band 21 can be the same or different, and the troughs of each heating band 21 can also be the same or different. The peaks of two adjacent heating bands 21 can be the same or different, and the troughs of two adjacent heating bands 21 can also be the same or different.

[0079] In the embodiment illustrated in this utility model, the plurality of heating belts 21 are stacked and wound together to form a disc shape. The heating belt assembly 2 comprises a plurality of layers radially from the inside out, wherein a gap 23 is provided between the inner layer heating belt assembly 2 and the outer layer heating belt assembly 2. The gap 23 is used to allow exhaust gas to pass through, thereby heating the exhaust gas using the heating belt assembly 2.

[0080] In the illustrated embodiment of this utility model, preferably, the length of each heating band 21 is the same, so as to distribute the current as evenly as possible to each heating band 21. In the illustrated embodiment of this utility model, both the first extension 211 and the second extension 212 are generally straight strips. Those skilled in the art will understand that the "straight strip" shape used in this utility model does not require that it be completely flat and completely straight; appropriate curvature is also acceptable. In one embodiment of this utility model, the first extension 211 and the second extension 212 may even be inclined relative to the wavy portion 210. In the illustrated embodiment of this utility model, the plurality of heating bands 21 include a first end 24 formed by the plurality of first extensions 211 and a second end 25 formed by the plurality of second extensions 212. In the illustrated embodiment of this utility model, the plurality of first extensions 211 of the first end 24 are parallel to each other, and the plurality of second extensions 212 of the second end 25 are also parallel to each other.

[0081] Preferably, in one embodiment of this utility model, the distance between any two adjacent first extensions 211 is equal; in other words, the first extensions 211 are arranged at equal intervals. Compared to a design where the first extensions 211 are stacked and squeezed together, this arrangement is less likely to cause heat concentration after power is applied, thereby reducing the risk of excessively high local temperatures.

[0082] Similarly, in one embodiment of this invention, the distance between any two adjacent second extensions 212 is equal; in other words, the second extensions 212 are arranged at equal intervals. Compared to a design where the second extensions 212 are stacked and compressed together, this arrangement is less likely to cause heat concentration after power is applied, thereby reducing the risk of excessively high local temperatures.

[0083] The first connecting block 5 is made of metal and includes a first mounting portion 51, a first connecting portion 52 connected to the first mounting portion 51, and a first clearance space 53 located inside the first mounting portion 51. The first mounting portion 51 includes a first surface 511 (e.g., an upper surface), a second surface 512 (e.g., a lower surface) opposite to the first surface 511, and a first fixing hole 513 penetrating the first surface 511 and the second surface 512 and communicating with the first clearance space 53. In one embodiment of the present invention, the first fixing hole 513 is an internally threaded hole. The first fixing hole 513 corresponds to the first mounting hole 13. In the embodiment illustrated in the present invention, the size of the first mounting hole 13 is larger than the size of the first fixing hole 513, thereby facilitating the passage of the first electrode assembly 3 through the first mounting hole 13 during assembly.

[0084] The first connecting portion 52 includes a first side surface 521, a second side surface 522 opposite to the first side surface 521, a first end surface 523, and a plurality of first mounting grooves 524 penetrating the first end surface 523. In the embodiment illustrated in this utility model, the first mounting grooves 524 penetrate the first side surface 521 and the second side surface 522 along the axial direction of the electric heater 100. The first mounting grooves 524 are used to accommodate the first extension 211. To improve the flexibility of installation, the length of the first mounting groove 524 is greater than the length of the first extension 211. This design, by accommodating the first extension 211 in the first mounting groove 524, helps to increase the contact area between the first extension 211 and the first connecting block 5, and helps to improve the connection stability between the two.

[0085] Similarly, the second connecting block 6 is made of metal and includes a second mounting portion 61, a second connecting portion 62 connected to the second mounting portion 61, and a second clearance space 63 located inside the second mounting portion 61. The second mounting portion 61 includes a third surface 611 (e.g., an outer surface), a fourth surface 612 (e.g., an inner surface) opposite to the third surface 611, and a second fixing hole 613 penetrating the third surface 611 and the fourth surface 612 and communicating with the second clearance space 63. In one embodiment of the present invention, the second fixing hole 613 is an internally threaded hole. The second fixing hole 613 corresponds to the second mounting hole 14. In the embodiment illustrated in the present invention, the size of the second mounting hole 14 is larger than the size of the second fixing hole 613, thereby facilitating the passage of the second electrode assembly 4 through the second mounting hole 14 during assembly.

[0086] The second connecting portion 62 includes a third side surface 621, a fourth side surface 622 opposite to the third side surface 621, a second end surface 623, and a plurality of second mounting grooves 624 penetrating the second end surface 623. In the embodiment illustrated in this utility model, the second mounting grooves 624 penetrate the third side surface 621 and the fourth side surface 622 along the axial direction of the electric heater 100. The second mounting grooves 624 are used to accommodate the second extension 212. To improve the flexibility of installation, the length of the second mounting groove 624 is greater than the length of the second extension 212. This design, by accommodating the second extension 212 in the second mounting groove 624, helps to increase the contact area between the second extension 212 and the second connecting block 6, and helps to improve the connection stability between the two.

[0087] The first electrode assembly 3 includes a first electrode 31, a first insulating portion 32 disposed on the first electrode 31, and a first shielding portion 33 fixed to the first insulating portion 32. In one embodiment of the present invention, the first electrode 31 includes a first main body portion 311, a first transition portion 312 connected to one end of the first main body portion 311, a first fixing portion 313 connected to the other end of the first main body portion 311, and a first external thread portion 314 connected to the first transition portion 312. In the embodiment illustrated in the present invention, the first external thread portion 314, the first transition portion 312, the first main body portion 311, and the first fixing portion 313 are connected sequentially. In the embodiment illustrated in the present invention, the outer diameter of the first main body portion 311 is larger than the outer diameter of the first external thread portion 314. The first transition portion 312 is frustum-shaped, including a large-diameter end connected to the first main body portion 311 and a small-diameter end connected to the first external thread portion 314, thereby causing the first main body portion 311, the first transition portion 312, and the first external thread portion 314 to gradually change. The outer diameter of the first fixing part 313 is smaller than the outer diameter of the first main body part 311.

[0088] In the embodiment illustrated in this utility model, the first insulating part 32 is a ceramic sleeve, which is sleeved on the first main body part 311 to insulate the first electrode 31 from the first shielding part 33. The first shielding part 33 is provided with a first through hole 330, and the first insulating part 32 is fixed in the first through hole 330 by an interference fit.

[0089] Of course, those skilled in the art will understand that the first insulating part 32 is also an insulating coating (such as a ceramic coating) plated on the first main body part 311, which can also play an insulating role, and this utility model will not elaborate further on this.

[0090] In the illustrated embodiment of this utility model, the first shielding portion 33 is welded and fixed to the outer surface 11 of the housing 1, and the first shielding portion 33 shields the first mounting hole 13. Furthermore, to prevent the heat generated during welding from damaging the first electrode 31 and / or the first insulating portion 32, a first clearance hole 331 is provided inside the first shielding portion 33 to quickly reduce heat transfer by allowing air to pass through. In the illustrated embodiment of this utility model, the first clearance hole 331 is generally tapered, with its diameter at the end radially closer to the heating band assembly 2 being larger than the diameter at the end farther from the heating band assembly 2.

[0091] In the embodiment illustrated in this utility model, the first shielding part 33 is provided with a first force-applying part 332, which is a hexagonal nut that includes six outer surfaces.

[0092] In the embodiment illustrated in this utility model, the first electrode 31, the first insulating part 32, and the first shielding part 33 are assembled into an integral first electrode assembly 3. Then, the first electrode assembly 3 is passed through the first mounting hole 13. In the embodiment illustrated in this utility model, the diameter of the first mounting hole 13 is larger than the outer diameter of the first electrode assembly 3 at the position corresponding to the first mounting hole 13, thereby making it easier for the first electrode assembly 3 to pass through the first mounting hole 13. This design improves the flexibility of installation and enhances the convenience of installation. The first fixing part 313 passes through the first mounting hole 13 and is fixed in the first fixing hole 513. In one embodiment of this utility model, the first fixing part 313 has an external thread (not shown), which engages with the internal thread of the first fixing hole 513. The external thread of the first fixing part 313 can be tightened with the internal thread of the first fixing hole 513 using the hexagonal nut and a matching installation tool. When the first electrode assembly 3 is installed in place, the first shielding part 33 is located between the first electrode 31 and the first shielding part 33, and the first shielding part 33 extends through the first mounting hole 13 and the first clearance hole 331, and at least partially extends into the mounting space 10.

[0093] Of course, those skilled in the art will understand that the first shielding part 33 may not have the first force-applying part 332. In this case, when installing the first electrode assembly 3 onto the first connecting block 5, the first external thread 314 can be used, and an installation tool can be used to tighten the external thread of the first fixing part 313 and the internal thread of the first fixing hole 513.

[0094] In the illustrated embodiment of this utility model, the first fixing part 313 protrudes from the second surface 512 to facilitate observation of the installation. The first fixing part 313 partially protrudes into the first clearance space 53; however, a suitable safe distance is maintained between the end of the first fixing part 313 and the heating band assembly 2 directly opposite it, preventing direct contact between the end of the first fixing part 313 and the heating band assembly 2. Those skilled in the art will understand that by providing the first clearance space 53, this utility model helps to reduce the risk of direct contact between the end of the first fixing part 313 and the heating band assembly 2 directly opposite it.

[0095] Compared with related technologies, this utility model achieves the connection and fixation of the first electrode 31 and the first connecting block 5 through mechanical connection, avoiding the damage to the first electrode 31 that may be caused by the high temperature generated during welding connection.

[0096] Similarly, the second electrode assembly 4 includes a second electrode 41, a second insulating portion 42 disposed on the second electrode 41, and a second shielding portion 43 fixed to the second insulating portion 42. In one embodiment of the present invention, the second electrode 41 includes a second main body portion 411, a second transition portion 412 connected to one end of the second main body portion 411, a second fixing portion 413 connected to the other end of the second main body portion 411, and a second external thread portion 414 connected to the second transition portion 412. In the embodiment illustrated in the present invention, the second external thread portion 414, the second transition portion 412, the second main body portion 411, and the second fixing portion 413 are connected sequentially. In the embodiment illustrated in the present invention, the outer diameter of the second main body portion 411 is larger than the outer diameter of the second external thread portion 414. The second transition portion 412 is frustum-shaped, including a large-diameter end connected to the second main body portion 411 and a small-diameter end connected to the second external thread portion 414, thereby causing the second main body portion 411, the second transition portion 412, and the second external thread portion 414 to gradually change. The outer diameter of the second fixing part 413 is smaller than the outer diameter of the second main body part 411.

[0097] In the embodiment illustrated in this utility model, the second insulating part 42 is a ceramic sleeve, which is sleeved on the second main body part 411 to insulate the second electrode 41 from the second shielding part 43. The second shielding part 43 is provided with a second through hole 430, and the second insulating part 42 is fixed in the second through hole 430 by an interference fit.

[0098] Of course, those skilled in the art will understand that the second insulating part 42 is also an insulating coating (such as a ceramic coating) plated on the second main body part 411, which can also play an insulating role, and this utility model will not elaborate further on this.

[0099] In the illustrated embodiment of this utility model, the second shielding part 43 is welded and fixed to the outer surface 11 of the housing 1, and the second shielding part 43 shields the second mounting hole 14. Furthermore, to prevent the heat generated during welding from damaging the second electrode 41 and / or the second insulating part 42, a second clearance hole 431 is provided inside the second shielding part 43 to quickly reduce heat transfer by allowing air to pass through. In the illustrated embodiment of this utility model, the second clearance hole 431 is generally tapered, with its diameter at the end radially closer to the heating band assembly 2 being larger than the diameter at the end farther from the heating band assembly 2.

[0100] In the embodiment illustrated in this utility model, the second shielding part 43 is provided with a second force-applying part 432, which is a hexagonal nut that includes six outer surfaces.

[0101] In the illustrated embodiment of this utility model, the second electrode 41, the second insulating part 42, and the second shielding part 43 are assembled into an integral second electrode assembly 4. Then, the second electrode assembly 4 is passed through the second mounting hole 14. In the illustrated embodiment of this utility model, the diameter of the second mounting hole 14 is larger than the outer diameter of the second electrode assembly 4 at the position corresponding to the second mounting hole 14, thereby making it easier for the second electrode assembly 4 to pass through the second mounting hole 14. This design improves the flexibility of installation and enhances installation convenience. The second fixing part 413 passes through the second mounting hole 14 and is fixed in the second fixing hole 613. In one embodiment of this utility model, the second fixing part 413 has an external thread (not shown), which engages with the internal thread of the second fixing hole 613. The external thread of the second fixing part 413 can be tightened into the internal thread of the second fixing hole 613 using the hexagonal nut and a matching installation tool. When the second electrode assembly 4 is installed in place, the second shielding part 43 is located between the second electrode 41 and the second shielding part 43, and the second shielding part 43 extends through the second mounting hole 14 and the second clearance hole 431, and at least partially extends into the mounting space 10.

[0102] Of course, those skilled in the art will understand that the second shielding part 43 may not have the second force-applying part 432. In this case, when installing the second electrode assembly 4 onto the second connecting block 6, the second external thread 414 can be used, and an installation tool can be used to tighten the external thread of the second fixing part 413 and the internal thread of the second fixing hole 613.

[0103] In the illustrated embodiment of this utility model, the second fixing part 413 protrudes from the fourth surface 612 to facilitate observation of the installation. The second fixing part 413 partially protrudes into the second clearance space 63; however, a suitable safe distance is maintained between the end of the second fixing part 413 and the heating band assembly 2 directly opposite it, preventing direct contact between the end of the second fixing part 413 and the heating band assembly 2 directly opposite it. Those skilled in the art will understand that by providing the second clearance space 63, this utility model helps to reduce the risk of direct contact between the end of the second fixing part 413 and the heating band assembly 2 directly opposite it.

[0104] This invention achieves the connection and fixation of the second electrode 41 and the second connecting block 6 through mechanical connection, avoiding potential damage to the second electrode 41 caused by the high temperature generated during welding.

[0105] Those skilled in the art will understand that in this invention, one of the first electrode 31 and the second electrode 41 is a positive electrode, and the other is a negative electrode. Preferably, the first electrode assembly 3 and the second electrode assembly 4 have identical structures to share components and save costs. Preferably, the first connecting block 5 and the second connecting block 6 have identical structures to share components and save costs.

[0106] The support frame 7 is made of metal. The support frame 7 includes an inner edge 71, an outer edge 72, and a plurality of spokes 73 connecting the inner edge 71 and the outer edge 72. The outer edge 72 lies on a circular outline. The outer edge 72 has a first notch 721 and a second notch 722, wherein the first notch 721 corresponds to the first electrode assembly 3, and the second notch 722 corresponds to the second electrode assembly 4. The first notch 721 and the second notch 722 allow exhaust gas to pass through, reducing obstruction of the first electrode assembly 3 and the second electrode assembly 4, thereby helping to reduce the risk of overheating of the first electrode 31 and the second electrode 41. The inner edge 71 has a perimeter-encircling frame shape to increase structural strength.

[0107] Those skilled in the art will understand that, typically, to improve structural strength, the outer edge 72 is designed as an integral frame structure. However, this design causes the frame structure to obstruct the first electrode assembly 3 and the second electrode assembly 4, hindering heat dissipation. This invention innovatively designs the first notch 721 and the second notch 722, solving the risk of overheating of the first electrode 31 and the second electrode 41 due to being blocked by the outer edge 72.

[0108] In the embodiment illustrated in this utility model, the outer edge 72 is welded and fixed to the inner surface 12 of the housing 1 to be fixed to the housing 1.

[0109] The inner edge 71 and the outer edge 72 are connected by spokes 73, which strengthen the structure. In the embodiment illustrated in this utility model, each spoke 73 has several mounting holes 731. Preferably, the mounting holes 731 are oblong. Of course, those skilled in the art will understand that the mounting holes 731 can also be designed in other shapes. The mounting holes 731 can adjust the installation tolerance, which helps to improve the convenience of assembling the pin assembly 8.

[0110] The pin assembly 8 includes a pin 81, a first ceramic sleeve 82, a second ceramic sleeve 83, and an end cap 84. In one embodiment of the present invention, both the pin 81 and the end cap 84 are made of metal. The pin 81 includes an abutment portion 811 and a pin portion 812 connected to the abutment portion 811. The first ceramic sleeve 82 includes a first base 821 and a first cylindrical portion 822 connected to the first base 821. The first base 821 has a first insertion hole 8211, and the first cylindrical portion 822 has a channel 8221 communicating with the first insertion hole 8211. The second ceramic sleeve 83 includes a second insertion hole 831. The end cap 84 has an installation insertion hole 841. In the embodiment illustrated in the present invention, the end cap 84 is generally spherical. Of course, those skilled in the art will understand that the shape of the end cap 84 can also be other shapes, and the present invention is not limited thereto.

[0111] During assembly, the pin 81 is first inserted into the channel 8221 of the first ceramic sleeve 82 through the first insertion hole 8211. The abutting portion 811 abuts against the first base 821 to limit the position of the abutting portion 811. The pin portion 812 passes through the first cylindrical portion 822 and extends out of the first cylindrical portion 822. Then, the pin 81 and the first ceramic sleeve 82 are inserted as a whole into the corresponding gap hole 22, with the first cylindrical portion 822 of the first ceramic sleeve 82 located in the corresponding gap hole 22 to prevent the pin 81 from contacting the heating belt assembly 2. Then, the second ceramic sleeve 83 is fitted onto the pin portion 812, with the pin portion 812 passing through the second insertion hole 831 and extending out of the second ceramic sleeve 83. At this time, the first base 821 of the first ceramic sleeve 82 and the second ceramic sleeve 83 are located on both sides of the heating belt assembly 2 along the axial direction. The pin portion 812 passes through the corresponding mounting hole 731 on the support frame 7. Then, the end cap 84 is fitted onto the pin portion 812. In the embodiment illustrated in this utility model, the pin portion 812 is inserted into the mounting hole 841 and extends beyond the end cap 84. Of course, those skilled in the art will understand that the pin portion 812 may not extend beyond the end cap 84. Finally, the end cap 84 is melted by heating. The melted end cap 84 serves as filler and solder, fixing the pin portion 812 and the support frame 7 together on one hand, and filling the mounting hole 731 on the other. Those skilled in the art will understand that the size of the mounting hole 731 in this utility model is larger than the size of the pin portion 812, so that the pin portion 812 can pass through the mounting hole 731. In addition, this utility model innovatively solves the problem of filling the mounting hole 731 by setting the end cap 84, which not only improves the aesthetics, but also increases the bonding force between the pin part 812 and the support frame 7.

[0112] The electric heater 100 of this utility model includes a first connecting block 5, which has a first fixing hole 513; the first electrode assembly 3 includes a first electrode 31, which has a first fixing part 313, and the first fixing part 313 is connected to the first fixing hole 513 by a threaded engagement; this arrangement avoids the structural reliability problems that may be caused by direct welding of the first electrode 31 to the heating band assembly 2, and improves durability.

[0113] Similarly, the electric heater 100 of this utility model includes a second connecting block 6, which has a second fixing hole 613; the second electrode assembly 4 includes a second electrode 41, which has a second fixing part 413, and the second fixing part 413 is connected to the second fixing hole 613 by a threaded engagement; this arrangement avoids the structural reliability problems that may be caused by direct welding of the second electrode 41 to the heating band assembly 2, and improves durability.

[0114] Furthermore, by providing the first connecting block 5 and the second connecting block 6 with the above structures, the present invention utilizes the first mounting groove 524 on the first connecting block 5 to accommodate the first extension 211 and the second mounting groove 624 on the second connecting block 6 to accommodate the second extension 212. This facilitates the relatively uniform distribution of current to each heating band 21 through the first connecting block 5 and the second connecting block 6, thereby improving the temperature uniformity of the electric heater 100 and reducing the risk of local overheating.

[0115] Please combine Figures 29 to 33 As shown, the second embodiment of this utility model discloses an electric heater 100, which is similar in structure to the electric heater 100 in the first embodiment. The main difference between the two lies in the structure of the first connecting block 5, the second connecting block 6 and the heating band 21.

[0116] Specifically, please combine Figures 29 to 31 As shown, in the second embodiment of the electric heater 100 of this utility model, the first connecting block 5 is further provided with a first welding groove 50, the opening direction of the first welding groove 50 facing the heating band assembly 2; the second connecting block 6 is further provided with a second welding groove 60, the opening direction of the second welding groove 60 facing the heating band assembly 2. When the first fixing part 313 of the first electrode 31 is connected to the first fixing hole 513 by a threaded engagement, the first electrode 31 is at least partially exposed in the first welding groove 50. By filling the first welding groove 50 with solder, the connection strength between the first fixing part 313 of the first electrode 31 and the first connecting block 5 can be further increased, thereby improving contact reliability. Similarly, when the second fixing part 413 of the second electrode 41 is connected to the second fixing hole 613 by a threaded engagement, the second electrode 41 is at least partially exposed in the second welding groove 60. By filling the second welding groove 60 with solder, the connection strength between the second fixing part 413 of the second electrode 41 and the second connecting block 6 can be further increased, thereby improving contact reliability.

[0117] Please combine Figures 31 to 33As shown in the illustrated embodiment of the electric heater 100 of this utility model, the heating band assembly 2 includes an S-shaped bend 26 located at its center. The S-shaped bend 26 includes a first outer bend 261 located on the outermost heating band 21a, a first inner bend 262 located on the outermost heating band 21a, a second inner bend 263 located on the innermost heating band 21b, and a second outer bend 264 located on the innermost heating band 21b. The first outer bend 261 and the second inner bend 263 are arranged opposite to each other, and the first inner bend 262 and the second outer bend 264 are arranged opposite to each other.

[0118] Regarding the S-shaped bend 26, if all heating bands 21 have the same thickness, the resistance distribution differs significantly between the inner and outer bends due to the length difference; the resistance of the inner bend is less than that of the outer bend. Therefore, when the heating band assembly 2 is powered on, the current follows the shortest path between the first inner bend 262 and the second inner bend 263, resulting in a smaller current flowing to the first outer bend 261 and the second outer bend 264. This causes the current density in the two inner bends to be much higher than in other areas, leading to severe localized heating. During use, this can easily cause premature melting and failure in the inner bend area.

[0119] To solve the above technical problems, please combine Figure 33 As shown, this invention employs a thinning design for the outermost heating band 21a and the innermost heating band 21b on the heating band assembly 2. In other words, the thickness T1 of the outermost heating band 21a and the thickness T2 of the innermost heating band 21b on the heating band assembly 2 are both less than the thickness T3 of any intermediate heating band 21c located between the outermost heating band 21a and the innermost heating band 21b.

[0120] In addition, as a further optimized technical solution, the curvature of the S-shaped bend 26 should be minimized as much as possible, so that the length difference between the inner bend and the outer bend caused by the different radii of curvature is minimized. This is also beneficial to reduce the resistance difference, thereby reducing local heat generation.

[0121] The above embodiments are only used to illustrate the present utility model and are not intended to limit the technical solutions described in the present utility model. The understanding of this specification should be based on those skilled in the art. Although the present utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to the present utility model. All technical solutions and improvements that do not depart from the spirit and scope of the present utility model should be covered within the scope of the claims of the present utility model.

Claims

1. An electric heater (100), characterized in that, include: A housing (1), the housing (1) including a mounting space (10); A heating band assembly (2) is located at least partially in the installation space (10). The heating band assembly (2) includes several layers of heating bands (21) stacked and wound together to form a disc. The heating band assembly (2) includes an S-shaped bend (26) at its center. The S-shaped bend (26) includes an outermost heating band (21a), an innermost heating band (21b), and an intermediate heating band (21c) located between the outermost heating band (21a) and the innermost heating band (21b). The thickness of the outermost heating band (21a) and the thickness of the innermost heating band (21b) are both less than the thickness of the intermediate heating band (21c). A first electrode assembly (3) includes a first electrode (31) which is electrically connected to the heating band assembly (2). The second electrode assembly (4) includes a second electrode (41) which is electrically connected to the heating band assembly (2). One of the first electrode (31) and the second electrode (41) is a positive electrode, and the other is a negative electrode.

2. The electric heater (100) as described in claim 1, characterized in that: The S-shaped bend (26) includes a first outer bend (261) on the outermost heating band (21a), a first inner bend (262) on the outermost heating band (21a), a second inner bend (263) on the innermost heating band (21b), and a second outer bend (264) on the innermost heating band (21b); the first outer bend (261) and the second inner bend (263) are arranged opposite to each other, and the first inner bend (262) and the second outer bend (264) are arranged opposite to each other.

3. The electric heater (100) as described in claim 1, characterized in that: Each layer of heating band (21) includes a wave section (210), a first extension (211) connected to one end of the wave section (210), and a second extension (212) connected to the other end of the wave section (210); The electric heater (100) also includes: The first connecting block (5) is provided with a plurality of first mounting slots (524), and the first extension (211) is at least partially received in the first mounting slots (524); The second connecting block (6) is provided with a plurality of second mounting slots (624), and the second extension (212) is at least partially received in the second mounting slots (624).

4. The electric heater (100) as described in claim 3, characterized in that: The first electrode (31) is connected to the first connecting block (5), and the second electrode (41) is connected to the second connecting block (6).

5. The electric heater (100) as described in claim 4, characterized in that: The housing (1) includes an outer surface (11), an inner surface (12) opposite to the outer surface (11), and a first mounting hole (13) that penetrates the outer surface (11) and the inner surface (12) and communicates with the mounting space (10); The first connecting block (5) is provided with a first fixing hole (513); The first electrode (31) is provided with a first fixing part (313), which passes through the first mounting hole (13) and is connected to the first fixing hole (513) by means of thread engagement.

6. The electric heater (100) as described in claim 5, characterized in that: The first fixing hole (513) is provided with an internal thread, and the first fixing part (313) is provided with an external thread, and the internal thread and the external thread are engaged.

7. The electric heater (100) as claimed in claim 5, characterized in that: The first connecting block (5) is provided with a first welding groove (50), and the opening direction of the first welding groove (50) faces the heating belt assembly (2); when the first fixing part (313) of the first electrode (31) is connected to the first fixing hole (513) by means of thread engagement, the first electrode (31) is at least partially exposed in the first welding groove (50).

8. The electric heater (100) as claimed in claim 7, characterized in that: The first welding groove (50) is used to fill the solder to fix the first fixing part (313) of the first electrode (31) together with the first connecting block (5).

9. The electric heater (100) as claimed in claim 5, characterized in that: The first connecting block (5) is made of metal material and includes a first mounting part (51), a first connecting part (52) connected to the first mounting part (51), and a first clearance space (53) located inside the first mounting part (51). The first mounting portion (51) includes a first surface (511) and a second surface (512) opposite to the first surface (511). The first fixing hole (513) is provided in the first mounting portion (51). The first fixing hole (513) passes through the first surface (511) and the second surface (512) and communicates with the first clearance space (53).

10. A tail gas aftertreatment device, characterized in that, include: Intake assembly (200); An electric heater (100) located downstream of the air intake assembly (200) along the airflow direction; A first exhaust gas aftertreatment module (300) located downstream of the electric heater (100) along the airflow direction; A second exhaust gas aftertreatment module (400) located downstream of the first exhaust gas aftertreatment module (300) along the airflow direction; A mixer assembly (500) located downstream of the second exhaust gas aftertreatment module (400) along the airflow direction; A third exhaust gas aftertreatment module (700) located downstream of the mixer assembly (500) along the airflow direction; as well as An exhaust assembly (800) located downstream of the third exhaust gas aftertreatment module (700) along the airflow direction; The electric heater (100) is the electric heater (100) as described in any one of claims 1 to 9.

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