Preparation method of exhaust assembly with integrated thermal insulation coating

Abstract

This invention provides a method for preparing an integrated thermal insulation coating for exhaust components, belonging to the field of thermal insulation coating material preparation. It is used to prepare a thermal insulation coating layer consisting of a hot-side coating layer, a high-temperature suppression layer, a medium-temperature barrier layer, a cold-side thermal resistance layer, a cold-side coating layer, and a cold-side protective layer, arranged sequentially from hot to cold side. Specifically, it includes: Step S1, sequentially cutting the coating layer and reflective layer; Step S2, cutting and pre-treating the high-temperature thermal resistance layer, medium-temperature thermal resistance layer, and cold-side thermal resistance layer respectively; Step S3, layering and coating the hot-side coating layer, high-temperature suppression layer, medium-temperature barrier layer, cold-side thermal resistance layer, and cold-side coating layer; Step S4, preparing an integrated cold-side protective layer and fixing it in place. This preparation method, through an integrated molding process, produces a gradient, lightweight, and compact thermal insulation coating layer that achieves perfect fit with the exhaust component, provides efficient thermal insulation, and exhibits excellent resistance to impermeability and corrosion.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation coating material preparation technology, and specifically to a method for preparing an integrated thermal insulation coating layer for exhaust components. Background Technology

[0002] Currently, special vehicles, due to their need to cope with various complex terrains, have engines with high power consumption and high output, resulting in high exhaust component surface temperatures (typically exceeding 950℃). If the high temperature on the exhaust component surface cannot be insulated, it will: 1) easily affect surrounding components, accelerating their aging and impacting the overall vehicle lifespan; 2) easily form temperature accumulation points in confined spaces, leading to localized high temperatures that affect vehicle performance and ride comfort; and 3) sustained high temperatures can cause flammable materials in the vehicle to ignite, damage electronic components, and create safety hazards. Currently, heat transfer mainly includes three modes: heat conduction, heat radiation, and heat convection. Exhaust component thermal protection primarily involves heat radiation and heat conduction. To avoid safety hazards, equipment aging, and decreased vehicle performance caused by high temperatures, it is generally necessary to cover the exhaust component with a heat insulation layer to isolate heat transfer and reduce the hazards of high temperatures. However, existing exhaust component heat insulation layers are heavy, thick, have poor insulation performance, and poor long-term stability, failing to meet the lightweight design requirements of modern vehicle engineering and thus unable to achieve efficient and long-term heat insulation for the entire vehicle.

[0003] Meanwhile, the confined space and complex operating conditions of a vehicle's engine necessitate careful consideration of resistance to liquid penetration and salt spray corrosion when designing the thermal insulation layer. This is crucial to prevent issues such as layer detachment and reduced insulation effectiveness due to liquid penetration or salt spray corrosion. Existing exhaust component thermal insulation layers typically utilize a metal shell as their protective layer. To meet the demands of the vehicle's limited space and avoid interference with other components, the protective shell is usually designed as a contoured structure (i.e., the shape of the protective shell matches and fits the exhaust component perfectly). Most existing exhaust components are irregularly shaped curved surfaces to meet the vehicle's space requirements. These irregular curved surfaces are generally formed by manual cutting and welding to ensure a perfect fit between each surface and the exhaust component's shape. However, this method has several drawbacks: firstly, it easily leads to welding gaps and connection seams, allowing liquid or salt spray penetration; secondly, it results in low manufacturing efficiency, increased production time and costs; and thirdly, the protective shell is typically thin, making it prone to scratches and damage during large-area cutting or welding, increasing the product defect rate. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a method for preparing an integrated heat insulation coating for exhaust components. This method uses an integrated molding process to prepare a gradient-type lightweight and compact heat insulation coating, which can achieve a perfect fit with the exhaust components and achieve high-efficiency heat insulation and resistance to liquid penetration and salt spray corrosion.

[0005] The objective of this invention is achieved through the following technical solution: A method for preparing an integrated thermal insulation coating for an exhaust assembly is provided, comprising, from the hot side (i.e., the outer surface of the exhaust assembly) to the cold side, a hot-side coating, a high-temperature suppression layer, a medium-temperature barrier layer, a cold-side thermal resistance layer, a cold-side coating, and a cold-side protective layer; wherein, the high-temperature suppression layer is composed of alternating layers of a high-temperature reflective layer and a high-temperature thermal resistance layer, the medium-temperature barrier layer is composed of alternating layers of a medium-temperature reflective layer and a medium-temperature thermal resistance layer, and the cold-side protective layer is an integrally formed embossed metal foil; the embossed metal foil is defined as having an array of raised protrusions on a flat metal foil surface; The specific steps include: Step S1: Sequentially cut the coating layer (including hot coating layer and cold coating layer) and the reflective layer (including high temperature reflective layer and medium temperature reflective layer); Step S2: Perform the cutting and pretreatment of the high-temperature thermal resistance layer, the medium-temperature thermal resistance layer, and the cold-side thermal resistance layer respectively; Step S3: Lay up and stack the hot-faced coating layer, high-temperature inhibition layer, medium-temperature barrier layer, cold-faced thermal resistance layer, and cold-faced coating layer, and cover the exhaust component; Step S4: Prepare an integrally molded cold-surface protective layer, cover it on the surface of the cold-surface coating layer, and fix it by welding.

[0006] Based on further optimization of the above scheme, the material of the hot coating layer is any one of quartz fiber cloth and high silica glass fiber cloth, with a thickness of 0.1 to 0.5 mm; the material of the cold coating layer is any one of glass fiber cloth, high silica glass fiber cloth and basalt fiber cloth, with a thickness of 0.1 to 0.8 mm.

[0007] Based on further optimization of the above scheme, the room temperature emissivity of the high-temperature reflective layer is no greater than 0.4, and its material is any one of stainless steel foil, molybdenum foil, and nickel foil, with a thickness of 0.015 to 0.08 mm; the room temperature thermal conductivity of the high-temperature thermal resistance layer is no greater than 0.05 W / (m·K), and its material is any one of mullite fiber felt, alumina fiber felt, and aluminum silicate fiber felt, with a thickness of 0.5 to 10 mm; at the same time, in the high-temperature suppression layer, the high-temperature reflective layer is closer to the heat coating layer, and the high-temperature thermal resistance layer is closer to the medium-temperature barrier layer, with a total number of 2 to 30 layers in the high-temperature suppression layer.

[0008] Based on further optimization of the above scheme, the room temperature emissivity of the medium-temperature reflective layer is no greater than 0.2, and its material is either titanium foil or aluminum foil, with a thickness of 0.015–0.08 mm; the room temperature thermal conductivity of the medium-temperature thermal resistance layer is no greater than 0.03 W / (m·K), and its material is glass fiber reinforced silica aerogel felt, with glass fiber accounting for 15%–45% of the total material weight of the glass fiber reinforced silica aerogel felt (i.e., silica aerogel accounting for 85%–55% of the total material weight), and its thickness is 0.5–5 mm; at the same time, in the medium-temperature barrier layer, the layer closest to the high-temperature suppression layer is the medium-temperature reflective layer, and the layer closest to the cold-side thermal resistance layer is the medium-temperature reflective layer, with the total number of layers of the medium-temperature barrier layer being 3–11.

[0009] The thermal coating layer covers the outer surface of the exhaust assembly, serving two purposes: firstly, it protects the outer surface from scratches; secondly, it ensures uniform heat conduction, preventing heat pooling. A high-temperature suppression layer, composed of alternating layers of high-temperature reflective and high-temperature thermal resistance layers, works in conjunction with the thermal coating layer to effectively reduce high-temperature heat radiation and enhance thermal protection. A medium-temperature barrier layer, composed of alternating layers of medium-temperature reflective and medium-temperature thermal resistance layers, creates a gradient with the high-temperature suppression layer, further improving thermal protection, and also reduces overall weight and thickness. A cold-faced thermal resistance layer, together with the high-temperature suppression and medium-temperature thermal resistance layers, forms a protective gradient (i.e., a gradual decrease in thermal conductivity), thereby achieving layer-by-layer blocking of heat radiation and conduction. Finally, the cold-faced coating layer ensures uniform heat conduction after reduction, preventing high-temperature pooling points, and, in conjunction with the cold-faced protective layer, forms a cavity matrix, further enhancing thermal insulation.

[0010] Based on further optimization of the above scheme, the room temperature thermal conductivity of the cold-surface thermal resistance layer is no greater than 0.02 W / (m·K), and its material is basalt fiber reinforced silica aerogel felt; wherein, the diameter of the basalt fiber is no greater than 6 μm, the basalt fiber accounts for 15% to 40% of the total material weight of the basalt fiber reinforced silica aerogel felt (i.e., silica aerogel accounts for 85% to 60% of the total material weight), and the bulk density of the preform formed by the basalt fiber is 60 to 70 kg / m³. 3 The density of silica aerogel is 50–60 kg / m³. 3 Its thickness is 1 to 10 mm.

[0011] Using fine-diameter basalt fibers as reinforcing fibers in nanoporous silica aerogels effectively limits the solid-state heat conduction of the fibers themselves, resulting in a low thermal conductivity for the basalt fiber felt. Simultaneously, the use of short-diameter basalt fibers to form a low-density preform further reduces the bulk density while maintaining the mechanical properties of the fiber-reinforced aerogel composite. Furthermore, the diameter of the fiber preform is close to the near-infrared wavelength, leading to strong diffraction and scattering of near-infrared radiation, thereby further enhancing the high-temperature infrared radiation heat conduction barrier effect. In addition, the addition of basalt fibers effectively solves the problems of high brittleness and easy breakage of pure aerogels.

[0012] Based on further optimization of the above scheme, the thickness of the cold-surface protective layer (in a flat state) is 0.02–0.5 mm, the diameter of the protrusions is 0.5–3.0 mm, and the height is 0.2–1.0 mm; the distance between two adjacent protrusions is 2–10 mm; and the number of protrusions per unit area in the cold-surface protective layer is 1.5 x 10. 4 ~6x10 4 One; the shape of the protrusion is any one of rice grain, pearl, or teardrop.

[0013] The protrusions serve several purposes: First, they utilize the strain hardening effect generated during the pressing process to enhance the rigidity and strength of the cold-faced protective layer, effectively reducing its thickness and meeting the design requirements for lightweight and compact structures. Second, they reduce wrinkles formed during the molding process, minimizing weak points and preventing damage to the protective layer, thus improving the overall liquid impermeability of the encapsulated structure. Third, the continuous uneven structure, combined with the cold-faced coating, forms a cavity matrix, altering the interlayer flow field and creating micro-gaps to effectively block heat conduction and suppress heat convection, enhancing insulation. Fourth, the uneven structure increases the heat dissipation area of ​​the metal shell (cold-faced protective layer), improving surface heat dissipation and preventing temperature accumulation points. Fifth, they achieve point contact between the cold-faced protective layer and the cold-faced coating, reducing heat conduction between them and allowing heat to dissipate within the cavity matrix, further improving insulation.

[0014] Based on further optimization of the above scheme, step S1 specifically includes: Step S11: Use a utility knife or scissors to cut the materials for the hot and cold coating layers according to the projected dimensions of the outer surface of the exhaust assembly. After cutting, stack them neatly for later use. The width and length of the cold coating layer should be 50-100 mm larger than those of the hot coating layer. Step S12: Using a metal foil cutting machine, the materials used as the high-temperature reflective layer and the medium-temperature reflective layer are cut and cut according to the outer surface contour projection size of the exhaust component. After cutting, they are neatly stacked for later use. Among them, the high-temperature reflective layer material is nickel plated after cutting.

[0015] Based on further optimization of the above scheme, step S2 specifically includes: Step S21, High-temperature thermal resistance layer cutting and pretreatment: First, use a paper cutter or scissors to cut and trim the high-temperature thermal resistance layer material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut high-temperature thermal resistance layer material. The pretreatment temperature is 650-750℃ and the time is 10-30 minutes. After the pretreatment is completed, stack them neatly for later use. Step S22, Medium-temperature thermal resistance layer cutting and pretreatment: First, use a paper cutter or scissors to cut the medium-temperature thermal resistance layer material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut medium-temperature thermal resistance layer material. The pretreatment temperature is 300-400℃ and the time is 2-6 hours. After the pretreatment is completed, stack them neatly for later use. Step S23, Cold surface thermal resistance layer cutting and pretreatment: First, use a paper cutter or scissors to cut the cold surface thermal resistance layer material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut cold surface thermal resistance layer material. The pretreatment temperature is 200-300℃ and the time is 2-6 minutes. After the pretreatment is completed, stack them neatly for later use.

[0016] Based on the further optimization of the above scheme, step S3 specifically includes: Step S31: First, the high-temperature reflective layer and the high-temperature thermal resistance layer are arranged alternately in sequence to form a high-temperature suppression layer. The medium-temperature reflective layer and the medium-temperature thermal resistance layer are arranged alternately in sequence to form a medium-temperature barrier layer. The high-temperature suppression layer, the medium-temperature barrier layer and the cold-side thermal resistance layer are then laid out and stacked in sequence. Then, high-temperature resistant fiber thread is used to sew the multi-layer structure (high-temperature suppression layer, medium-temperature barrier layer and cold-side thermal resistance layer) in a "well" shape. The stitch spacing is 5-20mm and the spacing between adjacent rows or columns is 50-150mm. Step S32: Wrap the hot-coated layer after cutting the material around the outer surface of the corresponding exhaust component, and use high-temperature resistant fiber thread to wrap and fix it and sew the seams. Step S33: Cover the surface of the hot-coated layer in step S32 with the multi-layer structure laid up in step S31, leaving the installation position of the exhaust component end to avoid interference with the bolt; then use high-temperature resistant fiber thread to wrap and fix it, and at the same time, the joint is butt-jointed, the butt joint is trimmed to a butt joint interface of 30-60° and sewn with high-temperature resistant fiber thread. Step S34: Wrap the cold-coated layer after cutting the material around the outer surface of the corresponding multi-layer structure, and use high-temperature resistant fiber thread to wrap and fix it and sew the seams. At the same time, trim the excess material according to the wrapping situation.

[0017] Based on further optimization of the above scheme, in order to improve the interlayer bonding force and ensure the compact structure, during the alternating arrangement and layering process in step S31, a high-temperature resistant flame retardant adhesive (a commonly used high-temperature resistant flame retardant adhesive in the art can be used) is applied between each layer.

[0018] Based on further optimization of the above scheme, the specific method for preparing the integrally formed cold surface protective layer in step S4 is as follows: Step S41: Design and process the stamping die according to the outer contour of the exhaust assembly; The stamping die includes a concave die and a convex die. The convex die includes a positioning plate, a first lifting mechanism, a second lifting mechanism, a fixed block, and a parting stamping mechanism. The top surface of the positioning plate is connected to the output end of the first lifting mechanism, and the second lifting mechanism is evenly arranged on the positioning plate on the outer ring of the first lifting mechanism. The bottom surface of the positioning plate is provided with a fixed block, and a through hole is opened in the middle of the fixed block corresponding to the outer contour of the exhaust component. The parting stamping mechanism is provided in the through hole, and the parting stamping mechanism is connected to the output end of the second lifting mechanism. The parting stamping mechanism includes a stamping base, a sliding connecting plate, parting stamping blocks, and a drive assembly. The stamping base is designed with an irregular surface according to the outer contour of the exhaust assembly, and the sliding connecting plate is set on the end face of the stamping base through multiple connecting columns. Multiple protrusions are arrayed on the bottom surface of the stamping base (i.e., the side away from the sliding connecting plate) (the protrusions are set according to the protrusion rules of the cold-face protection layer). The sliding connecting plate is parallel to the stamping base, and its outer wall is slidably connected to the through-hole sidewall. Multiple parting stamping blocks are slidably arranged between the end face of the stamping base and the bottom surface of the sliding connecting plate, located on the outer ring of the stamping base. These multiple parting stamping blocks form a complete sidewall of the outer contour of the exhaust assembly (the number of parting stamping blocks is specifically set according to the parting surface of the exhaust assembly's outer contour), and multiple protrusions are arrayed on the outer wall of the parting stamping blocks (i.e., the side near the through-hole sidewall) (the protrusions are set according to the protrusion rules of the cold-face protection layer). The parting stamping blocks are controlled by a drive assembly located between the stamping base and the sliding connecting plate. The sliding mechanism is controlled by a screw, a slider, and a connecting telescopic rod. The screw is rotatably mounted between the stamping base and the sliding connecting plate, and the outer wall of the screw is threaded onto the slider. The screw is configured to correspond to the parting stamping block, and one screw corresponds to at least two parting stamping blocks (the number of screws is set according to the actual number of parting stamping blocks). The shortest distance between the screw and each of its corresponding parting stamping blocks is consistent. The outer wall of the slider is connected to the inner wall of the corresponding parting stamping block (i.e., the side of the parting stamping block away from the through hole sidewall) through the connecting telescopic rod, and both ends of the connecting telescopic rod are rotatably connected to the outer wall of the slider and the inner wall of the parting stamping block, respectively. The connecting telescopic rod includes a positioning rod, a sliding rod, and a compression spring. The positioning rod, the sliding rod, and the compression spring are coaxially arranged. One end of the positioning rod is rotatably connected to the outer wall of the slider, and the other end has a spring groove. One end of the sliding rod is rotatably connected to the inner wall of the parting stamping block, and the other end is slidably engaged in the spring groove. The end of the sliding rod away from the parting stamping block is connected to the bottom of the spring groove through the compression spring. A forming groove is opened in the middle of the top surface of the die corresponding to the outer contour of the venting component. The bottom surface and side wall of the forming groove are respectively provided with grooves corresponding to the protrusion of the stamping base and the protrusion of the outer wall of the parting stamping block. Step S42: Preheat the metal sheet to be formed using an electric resistance furnace; Step S43: Place the preheated metal sheet on the end face of the concave mold and start the first lifting mechanism to preposition the fixed block on the metal sheet to prevent problems such as warping and curling of the metal sheet during the pressing process. Step S44: Start the second lifting mechanism to complete the pre-stamping of the metal sheet through the stamping base; then start the parting stamping mechanism to complete the secondary stamping of the metal sheet through the parting stamping block. Step S45: Manually demold the irregular curved embossed metal shell and trim the edges using machining.

[0019] Based on further optimization of the above scheme, the first lifting mechanism is set on the gantry support; the second lifting mechanism consists of 2 to 5 sets; both the first and second lifting mechanisms adopt hydraulic telescopic rods and are controlled by a hydraulic press.

[0020] Based on further optimization of the above scheme, the screw is driven by a motor and a sprocket and chain mechanism. The motor is fixedly installed on the top surface of the sliding connecting plate corresponding to the screw located near the geometric center of the stamping base. The output shaft of the motor passes through the sliding connecting plate and is fixedly connected to the top of the corresponding screw. The two adjacent screws are driven by a sprocket and chain mechanism.

[0021] Based on further optimization of the above scheme, the preheating temperature in step S42 is 100-300℃ and the preheating time is 1-4h.

[0022] Based on further optimization of the above scheme, after the positioning block prepositions the metal sheet in step S43, the distance between the bottom surface of the positioning block and the end face of the concave die is 1.5 to 2.5 times the thickness of the metal sheet.

[0023] Based on further optimization of the above scheme, the descent speed of the first lifting mechanism and the second lifting mechanism is 0.01 to 0.1 m / s; the pressure holding time after the pre-stamping is 1 to 5 min, and the pressure holding time after the second stamping is 5 to 15 min.

[0024] Based on further optimization of the above scheme, the welding method in step S4 is as follows: a precision welding machine is used to perform double-row staggered spot welding on the seam of the outer shell, with a spot spacing of 1 to 10 mm and a spot indentation diameter of 0.2 to 2 mm, to ensure that the spot welds are uniform, firm and reliable.

[0025] The following are the effects of the technical solution of the present invention: This application prepares a thermal insulation coating layer consisting of a hot-surface coating layer, a high-temperature inhibition layer, a medium-temperature barrier layer, a cold-surface thermal resistance layer, a cold-surface coating layer, and a cold-surface protective layer. Through the gradient thermal insulation layer arrangement, it can effectively prevent temperature accumulation and avoid the formation of heat accumulation points, thereby improving the thermal insulation effect. At the same time, through the integrated thermal insulation coating layer arrangement, there are no problems such as connection gaps or welding gaps. It has excellent resistance to liquid penetration and salt spray corrosion, a compact structure, stable long-term performance, and advantages such as lightweight and high-efficiency thermal insulation.

[0026] Meanwhile, the integrated thermal insulation coating structure obtained through the method of this application not only effectively improves the hardness and rigidity of the outermost cold-surface protective layer, avoiding problems such as deformation and cracking during use, but also prevents the formation of weak points such as wrinkles during the molding process of the cold-surface protective layer, thus improving its overall impermeability. It also avoids problems such as decreased thermal insulation and protective performance caused by uneven distribution of protrusions, irregular or incomplete structures during the pressing process. This results in an integrated thermal insulation coating structure with uniform and effective structure, excellent thermal insulation performance, strong protective performance, and good long-term stability. Furthermore, the method of this application results in high integration, fewer welding areas, and a simple overall process, effectively reducing the preparation time of the thermal insulation coating layer on the outer wall of the exhaust assembly, improving preparation efficiency, reducing process costs, and achieving a high product qualification rate. The prepared thermal insulation coating layer is lightweight, thin, and has high thermal insulation efficiency, meeting the usage requirements of the outer side of exhaust assemblies for special vehicles. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the heat insulation coating layer in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the microstructure of the cold-faced coating layer and the cold-faced protective layer in an embodiment of the present invention.

[0029] Figure 3 This is a diagram of the irregular structure of the cold-surface protective layer in an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram of the stamping die in an embodiment of the present invention.

[0031] Figure 5 for Figure 4 A magnified view of part A in the image.

[0032] Figure 6 for Figure 4 BB-direction sectional view.

[0033] Figure 7 for Figure 6 A magnified view of part C.

[0034] Figure 8 This is a stamping state diagram of the parting stamping mechanism in an embodiment of the present invention (relative to...). Figure 7 ).

[0035] Among them, 100 is the hot-faced coating layer; 200 is the high-temperature inhibition layer; 201 is the high-temperature reflective layer; 202 is the high-temperature thermal resistance layer; 300 is the medium-temperature barrier layer; 301 is the medium-temperature reflective layer; 302 is the medium-temperature thermal resistance layer; 400 is the cold-faced thermal resistance layer; 500 is the cold-faced coating layer; 600 is the cold-faced protective layer; 10 is the concave mold; 11 is the forming groove; 20 is the convex mold; 21 is the positioning plate; 22 is the first lifting mechanism; 23 is the second lifting mechanism; 24 is the fixed block; 240 is the through hole; 250 is the connecting column; 251 is the stamping base; 252 is the sliding connecting plate; 253 is the parting stamping block; 2541 is the screw; 2542 is the slider; 2543 is the connecting telescopic rod; 25431 is the positioning rod; 25432 is the sliding rod; 25433 is the compression spring; and 30 is the metal sheet. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] Example 1: A method for preparing an integrated thermal insulation coating for an exhaust assembly, comprising, from the hot side (i.e., the outer surface of the exhaust assembly) to the cold side, a hot-side coating 100, a high-temperature suppression layer 200, a medium-temperature barrier layer 300, a cold-side thermal resistance layer 400, a cold-side coating 500, and a cold-side protective layer 600 (e.g., a thermal insulation coating 100, a high-temperature suppression layer 200, a medium-temperature barrier layer 300, a cold-side thermal resistance layer 400, a cold-side coating 500, and a cold-side protective layer 600). Figure 1(as shown); wherein, the material of the hot-coating layer 100 is either quartz fiber cloth or high-silica glass fiber cloth (preferably quartz fiber cloth), and its thickness is 0.1-0.5 mm (preferably 0.3 mm). The high-temperature suppression layer 200 is composed of alternating layers of a high-temperature reflective layer 201 and a high-temperature thermal resistance layer 202. The high-temperature reflective layer 201 has a room temperature emissivity of no more than 0.4 and is made of any one of stainless steel foil, molybdenum foil, or nickel foil (preferably stainless steel foil), with a thickness of 0.015–0.08 mm (preferably 0.03 mm). The high-temperature thermal resistance layer 202 has a room temperature thermal conductivity of no more than 0.05 W / (m·K) and is made of any one of mullite fiber felt, alumina fiber felt, or aluminum silicate fiber felt (preferably mullite fiber felt), with a thickness of 0.5–10 mm (preferably 2 mm). Meanwhile, in the high-temperature suppression layer 200, the high-temperature reflective layer 201 is located near the heat-coating layer 100, and the high-temperature thermal resistance layer 202 is located near the medium-temperature barrier layer 300. The total number of layers of the high-temperature suppression layer 200, including the high-temperature reflective layer 201 and the high-temperature thermal resistance layer 202, is 2–30 layers (preferably 10 layers). The intermediate-temperature barrier layer 300 is composed of alternating layers of intermediate-temperature reflective layer 301 and intermediate-temperature thermal resistance layer 302. The room-temperature emissivity of the intermediate-temperature reflective layer 301 is not greater than 0.2, and its material is either titanium foil or aluminum foil (preferably titanium foil), with a thickness of 0.015–0.08 mm (preferably 0.03 mm). The room-temperature thermal conductivity of the intermediate-temperature thermal resistance layer 302 is not greater than 0.03 W / (m·K), and its material is glass fiber reinforced silica aerogel mat, with glass fiber accounting for 100% of the total weight of the glass fiber reinforced silica aerogel mat. The proportion of silica aerogel is 15% to 45% (i.e., silica aerogel accounts for 85% to 55% of the total material weight, preferably the ratio of glass fiber to silica aerogel is 30%:70%), and its thickness is 0.5 to 5 mm (preferably 2 mm); at the same time, the medium temperature barrier layer 300 has a medium temperature reflective layer 301 near the high temperature suppression layer 200 and a medium temperature reflective layer 302 near the cold surface thermal resistance layer 400, and the total number of medium temperature reflective layer 301 and medium temperature thermal resistance layer 302 in the medium temperature barrier layer 300 is 3 to 11 layers (preferably 5 layers). The thermal conductivity of the cold-surface thermal resistance layer 400 at room temperature is no greater than 0.02 W / (m·K), and its material is basalt fiber reinforced silica aerogel felt. The diameter of the basalt fibers is no greater than 6 μm, and the basalt fibers account for 15%–40% of the total weight of the basalt fiber reinforced silica aerogel felt (i.e., silica aerogel accounts for 85%–60% of the total weight, preferably a basalt fiber to silica ratio of 25%:75%). The bulk density of the preform formed by the basalt fibers is 60–70 kg / m³. 3 (Preferred weight: 65kg / m) 3 The density of silica aerogel is 50–60 kg / m³. 3 (Preferred weight: 55 kg / m) 3The thickness of the cold-faced protective layer 500 is 1–10 mm (preferably 3 mm). The material of the cold-faced protective layer 500 is any one of glass fiber cloth, high-silica glass fiber cloth, and basalt fiber cloth (preferably glass fiber cloth), and its thickness is 0.1–0.8 mm (preferably 0.3 mm). The cold-faced protective layer 600 is an integrally formed embossed metal foil; the embossed metal foil, such as… Figure 3 As shown, raised areas are arranged in an array on a flat metal foil surface (and the bonding diagram of the cold-faced protective layer 600 and the cold-faced coating layer 500 is shown in the figure). Figure 2 As shown); its thickness (in a flat state) is 0.02–0.5 mm (preferably 0.2 mm), the diameter of the protrusion is 0.5–3.0 mm (preferably 1 mm), and the height is 0.2–1.0 mm (preferably 0.6 mm); the distance between two adjacent protrusions is 2–10 mm (preferably 6 mm); the number of protrusions per unit area in the cold surface protective layer 600 is 1.5 x 10 4 ~6x10 4 (preferably 3.5x10) 4 (One); the shape of the protrusion is any one of rice grain shape, pearl shape, or teardrop shape (preferably pearl shape).

[0038] The specific steps include: Step S1: Sequentially cut the coating layers (including hot coating layer 100 and cold coating layer 500) and the reflective layers (including high-temperature reflective layer 201 and medium-temperature reflective layer 301): Step S11: Using a utility knife or scissors, cut the materials for the hot coating layer 100 and the cold coating layer 500 according to the projected dimensions of the outer surface of the exhaust assembly. After cutting, stack them neatly for later use. The cutting width and length of the cold coating layer 500 are 50-100 mm larger (preferably 75 mm) than those of the hot coating layer 100. Step S12: Using a metal foil cutting machine, the materials for the high-temperature reflective layer 201 and the medium-temperature reflective layer 301 are cut and cut according to the outer surface contour projection size of the exhaust assembly. After cutting, they are neatly stacked for later use. Among them, the high-temperature reflective layer 201 material is nickel-plated after cutting to improve its high-temperature oxidation resistance.

[0039] Step S2: Perform the cutting and pretreatment of the high-temperature thermal resistance layer 202, the medium-temperature thermal resistance layer 302, and the cold-surface thermal resistance layer 400 respectively. Step S21, High-temperature thermal resistance layer 202 cutting and pretreatment: First, use a paper cutter or scissors to cut and trim the high-temperature thermal resistance layer 202 material according to the projection size of the outer surface of the exhaust assembly; then, use a box-type resistance furnace to pretreat the cut high-temperature thermal resistance layer 202 material. The pretreatment temperature is 650-750℃ (preferably 700℃) and the time is 10-30min (preferably 20min). After the pretreatment is completed, stack them neatly for later use. Step S22, Medium-temperature thermal resistance layer 302 cutting and pretreatment: First, use a paper cutter or scissors to cut the medium-temperature thermal resistance layer 302 material according to the projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut medium-temperature thermal resistance layer 302 material. The pretreatment temperature is 300-400℃ (preferably 350℃) and the time is 2-6h (preferably 4h). After the pretreatment is completed, stack them neatly for later use. Step S23, Cold surface thermal resistance layer 400 cutting and pretreatment: First, use a paper cutter or scissors to cut and trim the cold surface thermal resistance layer 400 material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut cold surface thermal resistance layer 400 material. The pretreatment temperature is 200-300℃ (preferably 250℃) and the time is 2-6 minutes (preferably 4 minutes). After the pretreatment is completed, stack them neatly for later use.

[0040] Step S3: Lay up and stack the hot-surface coating layer 100, high-temperature inhibition layer 200, medium-temperature barrier layer 300, cold-surface thermal resistance layer 400, and cold-surface coating layer 500, and cover them with the venting assembly: Step S31: First, the high-temperature reflective layer 201 and the high-temperature thermal resistance layer 202 are arranged alternately in sequence to form a high-temperature suppression layer 200. The medium-temperature reflective layer 301 and the medium-temperature thermal resistance layer 302 are arranged alternately in sequence to form a medium-temperature barrier layer 300. The high-temperature suppression layer 200, the medium-temperature barrier layer 300 and the cold-side thermal resistance layer 400 are laid and stacked in sequence. During the alternating arrangement and layering process, high-temperature flame-retardant adhesive (common high-temperature flame-retardant adhesive in the art can be used) is applied between each layer. Then, using high-temperature resistant fiber thread (any common high-temperature resistant fiber thread in the field can be used, such as basalt fiber thread, aluminum silicate fiber, etc., which are not specifically limited in this embodiment, the same below) the multi-layer structure (high temperature inhibition layer 200, medium temperature barrier layer 300 and cold surface heat resistance layer 400) is sewn in a "well" shape, with the stitch spacing being 5-20mm (preferably 10mm) and the spacing between adjacent rows or columns being 50-150mm (preferably 80mm). Step S32: Wrap the hot-coated layer 100 after cutting the material around the outer surface of the corresponding exhaust component, and use high-temperature resistant fiber thread to wrap and fix it and sew the seams. The seam overlap width is 10-50mm (preferably 30mm). Step S33: Cover the surface of the hot-coated layer 100 in step S32 with the multi-layer structure laid up in step S31, leaving the installation position of the exhaust component end to avoid interference with the bolt; then use high-temperature resistant fiber thread to wrap and fix it, and at the same time, the joint is butt-jointed, the butt joint is trimmed to a butt joint interface of 30-60° (preferably 45°), and then sewn with high-temperature resistant fiber thread; Step S34: Wrap the cold-coated layer 500 after cutting the material around the outer surface of the corresponding multi-layer structure, and use high-temperature resistant fiber thread to wrap and fix it and sew the seams. The seam overlap width is 10-50mm (preferably 30mm). At the same time, trim the excess material according to the wrapping situation.

[0041] Step S4: Prepare the one-piece molded cold surface protective layer 600: Step S41: Design and process the stamping die according to the outer contour of the exhaust assembly; like Figure 4 As shown, the stamping die includes a concave die 10 and a convex die 20. The convex die 20 includes a positioning plate 21, a first lifting mechanism 22, a second lifting mechanism 23, a fixed block 24, and a parting stamping mechanism. The first lifting mechanism 22 is mounted on a gantry support (the gantry support can be set according to the actual situation, and its structure is a common structure in this field). The middle of the top surface of the positioning plate 21 is connected to the output end of the first lifting mechanism 22 (see...). Figure 4 As shown, the second lifting mechanism 23 is evenly arranged on the positioning plate 21 of the outer ring of the first lifting mechanism 22. There are 2 to 5 sets of the second lifting mechanism 23 (in this embodiment 2, 2 sets of the second lifting mechanism 23 are used). Both the first lifting mechanism 22 and the second lifting mechanism 23 adopt hydraulic telescopic rods and are controlled by hydraulic presses (both the hydraulic telescopic rods and hydraulic presses adopt common structures in the field, and are not specifically limited in this embodiment).

[0042] A fixed material block 24 is provided on the bottom surface (fixed) of the positioning plate 21, and a through hole 240 is opened in the middle of the fixed material block 24 corresponding to the outer contour of the exhaust component (in conjunction with...). Figure 4 and Figure 6 As shown), a parting stamping mechanism is provided in the through hole 240, and the parting stamping mechanism (specifically, the end face of the sliding connecting plate 252) is connected to the output end of the second lifting mechanism 23 (as shown). Figure 4 (As shown). The parting stamping mechanism includes a stamping base 251, a sliding connecting plate 252, a parting stamping block 253, and a drive assembly. The stamping base 251 is configured with an irregular surface according to the outer contour of the exhaust assembly (in conjunction with...). Figure 6 and Figure 7 (As shown) and the end face of the stamping base 251 is provided with a sliding connecting plate 252 through multiple connecting posts 250 (the number of connecting posts 250 is set according to the actual situation, such as...). Figure 7As shown, in this embodiment, the stamping base 251 and the sliding connecting plate 252 are connected by ten connecting posts 250. The bottom surface of the stamping base 251 (i.e., the side away from the sliding connecting plate 252) has multiple protrusions arranged in an array. The sliding connecting plate 252 is arranged parallel to the stamping base 251, and the outer wall of the sliding connecting plate 252 is slidably connected to the side wall of the through hole 240 (see...). Figure 4 (As shown); Multiple parting stamping blocks 253 are slidably arranged between the end face of the stamping base 251 and the bottom face of the sliding connecting plate 252, and located on the outer ring of the stamping base 251 (i.e., the bottom and end faces of the parting stamping blocks 253 are slidably connected to the end face of the stamping base 251 and the bottom face of the sliding connecting plate 252, respectively). These multiple parting stamping blocks 253 form the complete sidewall of the exhaust assembly's outer contour (the number of parting stamping blocks 253 is specifically set according to the parting surface of the exhaust assembly's outer contour; the parting surface is divided according to the curved surface of the exhaust assembly's outer contour, as shown in the reference). Figure 7 As shown, in this embodiment, there are eight parting stamping blocks 253, and the outer wall of the parting stamping block 253 (i.e., the side wall near the through hole 240) has multiple protrusions arranged in an array. The parting stamping block 253 is controlled to slide by a drive assembly disposed between the stamping base 251 and the sliding connecting plate 252. The drive assembly includes a screw 2541, a slider 2542, and a connecting telescopic rod 2543. The screw 2541 is rotatably disposed between the stamping base 251 and the sliding connecting plate 252, and the outer wall of the screw 2541 is threadedly sleeved with the slider 2542. The screw 2541 is set corresponding to the parting stamping block 253, and one screw 2541 corresponds to at least two parting stamping blocks 253 (the number of screws 2541 is set according to the actual number of parting stamping blocks 253, see reference). Figure 7 As shown, in this embodiment, three screws 2541 are provided. The middle screw 2541 corresponds to two parting stamping blocks 253, and the two screws 2541 on both sides correspond to three parting stamping blocks 253 respectively. The shortest distance between the screw 2541 and its corresponding parting stamping block 253 is the same. The outer wall of the slider 2542 is connected to the inner wall of the corresponding parting stamping block 253 (i.e., the side of the parting stamping block away from the through hole sidewall) by a connecting telescopic rod 2543 (see reference). Figure 7 As shown, two connecting telescopic rods 2543 are provided on the outer wall of the slider 2542 corresponding to the middle screw 2541, and three connecting telescopic rods 2543 are provided on the outer wall of the slider 2542 corresponding to the two screws 2541 on both sides, and the two ends of the connecting telescopic rods 2543 are rotatably connected to the outer wall of the slider 2542 and the inner wall of the parting stamping block 243 respectively through rotating seats; Figure 5 As shown: The connecting telescopic rod 2543 includes a positioning rod 25431, a sliding rod 25432, and a compression spring 25433. The positioning rod 25431, the sliding rod 25432, and the compression spring 25433 are coaxially arranged. One end of the positioning rod 25431 (i.e., Figure 5The upper right end (as shown) is rotatably connected to the outer wall of the slider 2542, and the other end (end end) has a spring groove. One end of the sliding rod 25432 (i.e. Figure 5 The lower left end of the sliding rod 25432 is rotatably connected to the inner wall of the parting stamping block 253, and the other end is slidably engaged in the spring groove. The end of the sliding rod 25432 away from the parting stamping block 253 is connected to the bottom of the spring groove through the compression spring 25433 (as shown). Figure 5 As shown). The screw 2541 achieves transmission through a motor and a sprocket and chain mechanism (combined with...). Figure 4 and Figure 6 As shown), a motor (with a protective outer shell around the motor) is fixedly mounted on the top surface of the sliding connecting plate 252 corresponding to the screw 2541 (the middle screw 2541 in this embodiment) located near the geometric center of the stamping base 251. The motor output shaft passes through the sliding connecting plate 252 and is fixedly connected to the top of the corresponding screw 2541 (thus enabling the rotation of the middle screw 2541). Adjacent screws 2541 are driven by a sprocket and chain mechanism (the sprocket and chain mechanism can use a common combination in the art, consisting of two drive wheels and a drive chain; the two drive wheels are respectively fixedly sleeved on the bottom outer walls of the two adjacent screws 2541, and the two drive wheels are connected by a drive chain). Figure 4 and Figure 6 (As shown).

[0043] A forming groove 11 is formed in the middle of the top surface of the die 10, corresponding to the outer contour of the venting component. The bottom surface and side walls of the forming groove 11 are respectively provided with grooves corresponding to the protrusions of the stamping base 251 and the outer wall of the parting stamping block 253. At the same time, the protrusion setting rules of the stamping base 251 and the parting stamping block 253 are set according to the protrusion rules of the cold surface protective layer 600.

[0044] Step S42: Preheat the metal sheet to be formed using an electric resistance furnace. The preheating temperature is 100-300℃ and the preheating time is 1-4 hours.

[0045] Step S43: Place the preheated metal sheet 30 on the end face of the concave mold 10 (e.g., Figure 1As shown), the first lifting mechanism 22 is activated, so that the fixed block 24 pre-positions the metal sheet 30. The descent speed of the first lifting mechanism 22 is 0.01~0.1m / s (preferably 0.05m / s). Specifically, the first lifting mechanism 22 is activated to extend, thereby driving the second lifting mechanism 23 and the fixed block 24 to move down simultaneously through the positioning plate 21. The second lifting mechanism 23 drives the entire parting stamping mechanism to move down with the fixed block 24 (at this time, the second lifting mechanism 23 is not activated) until the fixed block 24 reaches the designated position, then the first lifting mechanism 22 stops extending and holds pressure. After the fixed block 24 pre-positions the metal sheet 30, the distance between the bottom surface of the fixed block 24 and the end face of the die 10 is 1.5~2.5 times (preferably 2 times) the thickness of the metal sheet 30. This avoids the fixed block 24 from damaging or pressing the metal sheet 30 while preventing problems such as warping and curling of the metal sheet 30 during the pressing process.

[0046] Step S44: Activate the second lifting mechanism 23. The descent speed of the second lifting mechanism 23 is 0.01~0.1m / s (preferably 0.05m / s), completing the pre-stamping forming of the metal sheet 30. Specifically, the second lifting mechanism 23 is activated to extend, causing relative sliding between the sliding connecting plate 252 and the fixed block 24 in the vertical direction. This, in turn, pushes the stamping base 251 through the sliding connecting plate 252 and the connecting column 250. The bottom surface of the stamping base 251... Contacting the end face of the metal sheet 30, as the second lifting mechanism 23 continues to extend, the stamping base 251 pushes the metal sheet 30 into the forming groove 11, and forms a bottom protrusion with the groove at the bottom of the forming groove 11. At this time, the parting stamping block 253 is located inside the stamping base 251, and there is a certain gap between the outer wall of the parting stamping block 253 and the inner side wall of the forming groove 11. Therefore, the parting stamping block 253 does not stamp the side wall, avoiding problems such as rubbing or scratching of the side wall. The pressure holding time after pre-stamping is 1 to 5 minutes (preferably 3 minutes), that is, the interval between the completion of the bottom forming and the start of the second stamping forming, thereby ensuring that the bottom pattern is completely formed.

[0047] The parting stamping mechanism is restarted to complete the secondary stamping of the metal sheet 30. Specifically, the motor and sprocket chain mechanism start all screws 2541 to rotate simultaneously and in the same direction, causing the slider 2542 to move downward along the central axis of the corresponding screw 2541 on its outer wall. This, in turn, pushes the corresponding parting stamping block 253 outward through the connecting telescopic rod 2543 until the central axes of all connecting telescopic rods 2543 are on the same plane. At this time, the elastic force of the compression spring 25433 and the outwardly expanding parting stamping block 253 cooperate with the side wall of the forming groove 11 to stamp the side wall of the metal sheet 30. During the forming process, the pattern stamped on the bottom surface of the forming groove 11 by the stamping base 251 is used to position the metal sheet 30 and prevent the metal sheet 30 from shifting during the stamping process. The pressure holding time after the second stamping is 5 to 15 minutes (preferably 10 minutes), that is, the time from the completion of the side wall stamping to the reversal of the starting screw 2541.

[0048] Step S45: Manually demold the irregular curved embossed metal shell and trim the edges by machining (the conventional demolding and trimming methods in this field can be used, and no further limitations are made in this embodiment).

[0049] Finally, the molded and trimmed one-piece cold-faced protective layer 600 is wrapped around the surface of the cold-faced covering layer 500 and fixed by welding. The specific welding method is as follows: a precision welding machine (the model and structure of the precision resist welding machine are common equipment in this field, and no further limitations are made in this embodiment) is used to perform double-row staggered spot welding on the seam of the outer shell. The spacing between the weld points is 1 to 10 mm, and the diameter of the weld point indentation is 0.2 to 2 mm to ensure that the weld points are uniform, firm and reliable.

[0050] The thermal insulation layer with a total thickness of 18.04 mm, consisting of the preferred thicknesses of each layer in this embodiment (i.e., the hot surface covering layer 100 is 0.3 mm thick, the high temperature suppression layer 200 is composed of five layers of high temperature reflective layer 201 with a thickness of 0.03 mm and five layers of high temperature thermal resistance layer 202 with a thickness of 2 mm alternately stacked, the medium temperature barrier layer 300 is composed of three layers of medium temperature reflective layer 301 with a thickness of 0.03 mm and two layers of medium temperature thermal resistance layer 302 with a thickness of 2 mm alternately stacked, the cold surface thermal resistance layer 400 is 3 mm thick, the cold surface covering layer 500 is 0.3 mm thick, and the cold surface protective layer 600 is 0.2 mm thick), was placed in a test chamber for thermal insulation performance testing. When the hot surface temperature was 800°C, its cold surface temperature was 129.5°C, demonstrating excellent thermal insulation performance.

[0051] Example 2: As another preferred embodiment of the present invention, based on the scheme of embodiment 1, in order to avoid the metal sheet 30 from generating creases at the joint of adjacent parting stamping blocks 253 during the outward expansion of the parting stamping block 253, buffer rubber strips are respectively provided on both sides of the parting stamping block 253, and the inner cavity of the buffer rubber strip is set as a hollow structure (since the joint between the two parting stamping blocks 253 is small, the width setting value of the hollow structure is small). This achieves that when the parting stamping block 253 is retracted, it squeezes the buffer rubber strip to avoid mutual interference, and when the parting stamping block 253 is expanded outward, the buffer rubber strip fills the joint between the two parting stamping blocks 253 due to elastic reset.

[0052] Example 3: As another preferred embodiment of the present invention, based on the scheme of Embodiment 1 or Embodiment 2, in order to ensure that the stamped pattern is clear and complete, the metal sheet 30 can be pre-embossed, specifically as follows: Before step S41 above, the metal sheet 30 is pre-embossed to prepare an embossed metal blank with a pattern, including: First, install the metal foil roll, which has a thickness of 0.02–0.5 mm (preferably 0.2 mm) and a width of 100–1500 mm (selected according to the width of the components in the actual exhaust assembly). Then, unroll the roll, pull the roll head, and place it into the embossing machine (a common roller-type embossing machine in this field is acceptable), at its slowest speed. Next, install the rollers, where the patterns on the rollers include rice grain patterns, pearl patterns, and teardrop patterns, with a diameter of 0.5–3 mm (preferably 1.5 mm), and the number of raised patterns per unit area is 1.5 x 10⁻⁶. 4 ~6x10 4 (preferably 3.5 x 10) 4 The distance between two adjacent raised patterns is 2-10 mm (preferably 6 mm), and the spacing between the rollers is adjusted according to the thickness of the metal foil roll and the embossing height, wherein the raised pattern height is 0.2-1.0 mm (preferably 0.6 mm); then, it is pre-rolled by 1 mm, and the various dimensions of the pattern are measured to see if they meet the requirements. If they do not meet the requirements, the adjustment continues. If they meet the requirements, the unwinding and embossing machine are paused and the take-up core is fixed; finally, the unwinding, embossing machine and take-up yellow paper are started to pre-roll the metal pattern of the metal sheet 30.

[0053] After the pattern pre-rolling is completed, when the metal sheet 30 is placed on the end face of the die 10 in step S43 of the above embodiment 1, it is necessary to ensure that the pre-rolled pattern is placed in correspondence with the protrusion on the bottom surface of the stamping base 251, so as to ensure that the rolled pattern is clear and distinct.

Claims

1. A method for preparing an integrated heat insulation coating for an exhaust assembly, characterized in that: This is used to prepare a thermal insulation coating layer consisting of, from hot side to cold side, a hot-side covering layer, a high-temperature suppression layer, a medium-temperature barrier layer, a cold-side thermal resistance layer, a cold-side covering layer, and a cold-side protective layer. The high-temperature suppression layer is composed of alternating layers of a high-temperature reflective layer and a high-temperature thermal resistance layer. The room-temperature emissivity of the high-temperature reflective layer is no greater than 0.4, and the room-temperature thermal conductivity of the high-temperature thermal resistance layer is no greater than 0.05 W / (m·K). Furthermore, the high-temperature suppression layer has a high-temperature reflective layer closest to the hot-side covering layer and a medium-temperature barrier layer closest to the hot-side covering layer. The high-temperature thermal resistance layer consists of alternating layers of a medium-temperature reflective layer and a medium-temperature thermal resistance layer. The room temperature emissivity of the medium-temperature reflective layer is no greater than 0.2, and the room temperature thermal conductivity of the medium-temperature thermal resistance layer is no greater than 0.03 W / (m·K). In the medium-temperature barrier layer, the layer closest to the high-temperature suppression layer is the medium-temperature reflective layer, and the layer closest to the cold-side thermal resistance layer is the medium-temperature reflective layer. The cold-side protective layer is an integrally formed embossed metal foil, and the room temperature thermal conductivity of the cold-side thermal resistance layer is no greater than 0.02 W / (m·K). The specific steps include: Step S1: Sequentially cut the coating layer and reflective layer; Step S2: Perform the cutting and pretreatment of the high-temperature thermal resistance layer, the medium-temperature thermal resistance layer, and the cold-side thermal resistance layer respectively; Step S3: Lay up and stack the hot-faced coating layer, high-temperature inhibition layer, medium-temperature barrier layer, cold-faced thermal resistance layer, and cold-faced coating layer, and cover the exhaust component; Step S4: Prepare an integrally molded cold-surface protective layer, cover it on the surface of the cold-surface coating layer, and fix it by welding.

2. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 1, characterized in that: The hot-coating layer is made of either quartz fiber cloth or high-silica glass fiber cloth, with a thickness of 0.1 to 0.5 mm; the cold-coating layer is made of either glass fiber cloth, high-silica glass fiber cloth, or basalt fiber cloth, with a thickness of 0.1 to 0.8 mm.

3. A method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 1 or 2, characterized in that: The high-temperature reflective layer material is any one of stainless steel foil, molybdenum foil, and nickel foil, with a thickness of 0.015–0.08 mm; the high-temperature thermal resistance layer material is any one of mullite fiber felt, alumina fiber felt, and aluminum silicate fiber felt, with a thickness of 0.5–10 mm; the total number of layers in the high-temperature suppression layer, including the high-temperature reflective layer and the high-temperature thermal resistance layer, is 2–30 layers.

4. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 3, characterized in that: The medium-temperature reflective layer material is either titanium foil or aluminum foil, with a thickness of 0.015–0.08 mm; the medium-temperature thermal resistance layer material is glass fiber reinforced silica aerogel felt, with glass fiber accounting for 15%–45% of the total weight of the glass fiber reinforced silica aerogel felt, and a thickness of 0.5–5 mm; the total number of layers in the medium-temperature barrier layer, including the medium-temperature reflective layer and the medium-temperature thermal resistance layer, is 3–11.

5. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 3, characterized in that: The cold-surface thermal resistance layer material is basalt fiber reinforced silica aerogel felt; wherein the diameter of the basalt fiber is no greater than 6μm, the basalt fiber accounts for 15% to 40% of the total weight of the basalt fiber reinforced silica aerogel felt, and the bulk density of the preform formed by the basalt fiber is 60 to 70 kg / m³. 3 The density of silica aerogel is 50–60 kg / m³. 3 Its thickness is 1 to 10 mm.

6. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 1, characterized in that: Step S1 specifically involves: Step S11: Use a utility knife or scissors to cut the materials for the hot and cold coating layers according to the projected dimensions of the outer surface of the exhaust assembly. After cutting, stack them neatly for later use. The width and length of the cold coating layer should be 50-100 mm larger than those of the hot coating layer. Step S12: Using a metal foil cutting machine, the materials used as the high-temperature reflective layer and the medium-temperature reflective layer are cut and cut according to the outer surface contour projection size of the exhaust component. After cutting, they are neatly stacked for later use. Among them, the high-temperature reflective layer material is nickel plated after cutting.

7. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 6, characterized in that: Step S2 specifically involves: Step S21, High-temperature thermal resistance layer cutting and pretreatment: First, use a paper cutter or scissors to cut and trim the high-temperature thermal resistance layer material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut high-temperature thermal resistance layer material. The pretreatment temperature is 650-750℃ and the time is 10-30 minutes. After the pretreatment is completed, stack them neatly for later use. Step S22, Medium-temperature thermal resistance layer cutting and pretreatment: First, use a paper cutter or scissors to cut the medium-temperature thermal resistance layer material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut medium-temperature thermal resistance layer material. The pretreatment temperature is 300-400℃ and the time is 2-6 hours. After the pretreatment is completed, stack them neatly for later use. Step S23, Cold surface thermal resistance layer cutting and pretreatment: First, use a paper cutter or scissors to cut the cold surface thermal resistance layer material according to the outline projection size of the outer surface of the exhaust component; then, use a box-type resistance furnace to pretreat the cut cold surface thermal resistance layer material. The pretreatment temperature is 200-300℃ and the time is 2-6 minutes. After the pretreatment is completed, stack them neatly for later use.

8. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 7, characterized in that: Step S3 specifically involves: Step S31: First, the high-temperature reflective layer and the high-temperature thermal resistance layer are arranged alternately in sequence to form a high-temperature suppression layer. The medium-temperature reflective layer and the medium-temperature thermal resistance layer are arranged alternately in sequence to form a medium-temperature barrier layer. The high-temperature suppression layer, the medium-temperature barrier layer and the cold-side thermal resistance layer are then laid up and stacked in sequence. Then, the multi-layer structure after being laid up and stacked is sewn in a "well" shape using high-temperature resistant fiber thread. The stitch spacing is 5-20mm and the spacing between two adjacent rows or columns is 50-150mm. Step S32: Wrap the hot-coated layer after cutting the material around the outer surface of the corresponding exhaust component, and use high-temperature resistant fiber thread to wrap and fix it and sew the seams. Step S33: Cover the surface of the hot-coated layer in step S32 with the multi-layer structure laid up in step S31, leaving the installation position of the exhaust component end to avoid interference with the bolt; then use high-temperature resistant fiber thread to wrap and fix it, and at the same time, the joint is butt-jointed, the butt joint is trimmed to a butt joint interface of 30-60° and sewn with high-temperature resistant fiber thread. Step S34: Wrap the cold-coated layer after cutting the material around the outer surface of the corresponding multi-layer structure, and use high-temperature resistant fiber thread to wrap and fix it and sew the seams. At the same time, trim the excess material according to the wrapping situation.

9. The method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 8, characterized in that: The method for preparing the integrally formed cold surface protective layer in step S4 is as follows: Step S41: Design and process the stamping die according to the outer contour of the exhaust assembly; The stamping die includes a concave die and a convex die. The convex die includes a positioning plate, a first lifting mechanism, a second lifting mechanism, a fixed block, and a parting stamping mechanism. The top surface of the positioning plate is connected to the output end of the first lifting mechanism, and the second lifting mechanism is evenly arranged on the positioning plate on the outer ring of the first lifting mechanism. The bottom surface of the positioning plate is provided with a fixed block, and a through hole is opened in the middle of the fixed block corresponding to the outer contour of the exhaust component. The parting stamping mechanism is provided in the through hole, and the parting stamping mechanism is connected to the output end of the second lifting mechanism. The parting stamping mechanism includes a stamping base, a sliding connecting plate, parting stamping blocks, and a drive assembly. The stamping base is designed with an irregular shape according to the outer contour of the exhaust assembly, and the sliding connecting plate is set on the end face of the stamping base through multiple connecting columns. Multiple protrusions are arranged in an array on the bottom surface of the stamping base. The sliding connecting plate is parallel to the stamping base, and its outer wall is slidably connected to the side wall of the through hole. Multiple parting stamping blocks are slidably arranged between the end face of the stamping base and the bottom surface of the sliding connecting plate, located on the outer ring of the stamping base. These multiple parting stamping blocks form the complete side wall of the outer contour of the exhaust assembly, and multiple protrusions are arranged in an array on the outer wall of the parting stamping blocks. The parting stamping blocks are controlled to slide by a drive assembly located between the stamping base and the sliding connecting plate. The drive assembly includes a screw, a slider, and a connecting telescopic rod. The screw rotates... A slider is threaded onto the outer wall of a screw and positioned between a stamping base and a sliding connecting plate. The screw corresponds to a parting block, with each screw corresponding to at least two parting blocks. The shortest distance between the screw and each corresponding parting block is consistent. The outer wall of the slider is connected to the inner wall of the corresponding parting block via a connecting telescopic rod, with both ends of the connecting telescopic rod rotatably connected to the outer wall of the slider and the inner wall of the parting block, respectively. The connecting telescopic rod includes a positioning rod, a sliding rod, and a compression spring. The positioning rod, sliding rod, and compression spring are coaxially arranged. One end of the positioning rod is rotatably connected to the outer wall of the slider, and the other end has a spring groove. One end of the sliding rod is rotatably connected to the inner wall of the parting block, and the other end is slidably engaged in the spring groove. The end of the sliding rod furthest from the parting block is connected to the bottom of the spring groove via the compression spring. A forming groove is opened in the middle of the top surface of the die corresponding to the outer contour of the venting component. The bottom surface and side wall of the forming groove are respectively provided with grooves corresponding to the protrusion of the stamping base and the protrusion of the outer wall of the parting stamping block. Step S42: Preheat the metal sheet to be formed using an electric resistance furnace; Step S43: Place the preheated metal sheet on the end face of the concave mold and start the first lifting mechanism to preposition the fixed block on the metal sheet to prevent problems such as warping and curling of the metal sheet during the pressing process. Step S44: Start the second lifting mechanism to complete the pre-stamping of the metal sheet through the stamping base; then start the parting stamping mechanism to complete the secondary stamping of the metal sheet through the parting stamping block. Step S45: Manually demold the irregular curved embossed metal shell and trim the edges using machining.

10. A method for preparing an integrated heat insulation coating for an exhaust assembly according to claim 8, characterized in that: The welding method in step S4 is as follows: a precision welding machine is used to perform double-row staggered spot welding on the seam of the outer shell, with a weld spot spacing of 1 to 10 mm and a weld spot indentation diameter of 0.2 to 2 mm.

Images