Front silencer

Abstract

The utility model discloses a front silencer which comprises a silencer pipe body, a front silencer cover, a front silencer cover and a rear silencer cover. The silencer pipe body is provided with a plurality of silencing holes. The catalyst is used for treating NH3 pollutants, and the inner wall faces of at least part of the silencing holes are coated with the catalyst. Compared with the prior art, the silencer has the advantages that the catalyst capable of treating NH3 pollutants is coated in part of or all the silencing holes in the silencer pipe body, so that the function of treating NH3 of an exhaust system can be increased on the basis of not changing the structure of the existing exhaust system, the effect of reducing NH3 emission of a light gasoline car can be quickly realized, and the service life of the silencer is prolonged. The system is simple in structure, good in treatment effect and capable of meeting the harsh pollutant discharge requirement in the next stage.

Description

Technical Field

[0001] This utility model relates to the field of exhaust system technology, and in particular to a front muffler. Background Technology

[0002] In the exhaust system of light-duty gasoline vehicles, in conjunction with the existing muffler and aftertreatment system, a special catalytic coating is added to the front muffler to oxidize and render harmless the NH3 byproduct of the existing exhaust aftertreatment, thus meeting the requirements of the next stage of more stringent emission regulations. As a crucial component of the powertrain in engine-equipped vehicles, the exhaust system primarily functions to expel and treat engine exhaust gases, reducing pollution emissions and noise.

[0003] Currently, the industry generally treats the byproduct NH3 generated by TWC in the exhaust aftertreatment system by adding an AMOx catalyst to the catalytic converter section of the exhaust system or by adding AMOx functionality. This method generally uses ceramic carriers, but due to limitations such as structural design, material properties, and system back pressure, ceramic honeycomb carriers cannot achieve a small diameter.

[0004] On the other hand, this arrangement also has some shortcomings and limitations in practical application. Currently, in major global markets, plug-in hybrid electric vehicles (PHEVs) with low fuel consumption and low carbon emissions are becoming the mainstream. Their chassis are generally equipped with large batteries, which leads to many limitations in the design space of the exhaust system. It is impossible to place an additional catalyst at the rear of the exhaust pipe to enhance the control of pollutants and meet the more stringent pollutant emission regulations. Utility Model Content

[0005] The purpose of this invention is to provide a front silencer to solve the problems in the prior art, improve the ability to treat NH3 pollutants, and meet the more stringent pollutant emission requirements in the next stage.

[0006] This utility model provides a front muffler, comprising:

[0007] A muffler tube body, wherein the muffler tube body has multiple muffler holes;

[0008] A catalyst for treating NH3 pollutants, the catalyst being coated on at least a portion of the inner wall surface of the silencing holes.

[0009] In the aforementioned front muffler, preferably, the thickness of the catalyst coating is 20-300 μm.

[0010] In a front muffler as described above, preferably, the catalyst comprises a base layer and a slurry layer, the slurry layer being attached to the base layer.

[0011] In the aforementioned pre-silencer, preferably, the slurry layer comprises molecular sieve material, active material, supporting material, and additives.

[0012] In a front muffler as described above, preferably, the catalyst comprises a base layer and a slurry layer, the slurry layer comprising a first slurry layer and a second slurry layer, the first slurry layer being attached to the base layer, and the second slurry layer being attached to the side of the first slurry layer opposite to the base layer.

[0013] In the aforementioned front muffler, preferably, the first slurry layer comprises an active material and a supporting material, and the second slurry layer comprises a molecular sieve material and an additive.

[0014] In the aforementioned pre-silencer, preferably, the molecular sieve material includes one or more of Fe-CHA, Fe-BA, and Cu-CHA, the active material includes one or more of Pt and Rh, and the supporting material includes one or more of Al2O3 and TiO2.

[0015] In the aforementioned front muffler, preferably, the content of the active material is 0.005%-0.5%.

[0016] In the aforementioned front muffler, preferably, the slurry layer has a slurry solids content of 10%-45%.

[0017] In the aforementioned front muffler, preferably, the slurry particle size D90 of the slurry layer is 5-30 μm.

[0018] Compared with the prior art, this utility model coats part or all of the muffler holes on the muffler pipe with a catalyst that can treat NH3 pollutants. This allows the exhaust system to be enhanced with NH3 treatment capabilities without altering its existing structure. It can quickly reduce NH3 emissions from light-duty gasoline vehicles. The system has a simple structure, good treatment effect, and can meet the more stringent pollutant emission requirements of the next stage. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the internal structure of the front muffler provided in an embodiment of this utility model;

[0020] Figure 2 This is a schematic diagram of the catalyst coating on the muffler tube provided in an embodiment of this utility model;

[0021] Figure 3 This is a schematic diagram of the structure of the catalyst provided in one embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the catalyst provided in another embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 100-Front muffler;

[0025] 1-muffler tube body, 11-muffler hole;

[0026] 2-Catalyst, 21-Base layer, 22-Slurry layer, 221-First slurry layer, 222-Second slurry layer. Detailed Implementation

[0027] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0028] Reference Figure 1 as well as Figure 2 As shown, this utility model provides a front muffler 100, including a muffler tube 1 and a catalyst 2, wherein:

[0029] The muffler tube 1 has multiple muffler holes 11. The muffler holes 11 can not only absorb noise, but also further reduce noise through internal airflow and vibration.

[0030] Catalyst 2 is used to treat NH3 pollutants. Catalyst 2 is coated on at least part of the inner wall surface of the silencer hole 11, thereby making full use of the airflow channel inside the front silencer 100, increasing the contact area between NH3 and catalyst 2, and thus improving the treatment efficiency of NH3.

[0031] Compared to existing technologies that treat NH3 by adding catalyst 2 or adding catalytic function to the catalytic converter section of the exhaust system, the front muffler 100 of this application can enhance the ability to treat NH3 without changing the structure of the muffler and the exhaust system, thereby quickly achieving the effect of reducing NH3 emissions from light-duty gasoline vehicles to meet the requirements of the next stage of emission regulations.

[0032] In the embodiments provided in this application, catalyst 2 is AMO. x The AMOx catalyst can oxidize the unreacted excess NH3 in SCR (Selective Catalytic Reduction), preventing its direct emission into the air and controlling the AMO content. x NO inside X The generation of N2O (especially) reduces pollution.

[0033] Typical AMO xThe catalyst can achieve a conversion of approximately 50% or more of NH3 between 200°C and 250°C. Under specific operating conditions, its inlet temperature can exceed 200°C most of the time. Therefore, AMO is integrated into the front muffler 100. x Catalysts can achieve efficient treatment of NH3 pollutants, thereby enabling the treatment of NH3 pollutants.

[0034] In other embodiments, catalyst 2 may also be coated on the inner wall surface of all the silencing holes 11 to improve the treatment efficiency of NH3 pollutants. The coating should be applied according to the emission requirements and is not limited here.

[0035] The coating thickness of catalyst 2 is closely related to its catalytic performance and coatability. Based on the coating experience on metal carriers, controlling the thickness of catalyst 2 to 20-300μm can ensure its firm adhesion to the metal surface. Since catalyst 2 is coated on the wall of a through-hole metal tube, the effect of coating on back pressure can be ignored.

[0036] In one feasible implementation, refer to Figure 3 As shown, the catalyst 2 includes a base layer 21 and a slurry layer 22. The slurry layer 22 is attached to the base layer 21. The catalyst 2 in this embodiment is a single-layer slurry structure catalyst 2. The slurry layer 22 includes molecular sieve material, active material, supporting material and additives.

[0037] In another feasible implementation, refer to Figure 4 As shown, catalyst 2 includes a base layer 21 and a slurry layer 22. The slurry layer 22 includes a first slurry layer 221 and a second slurry layer 222. The first slurry layer 221 is attached to the base layer 21, and the second slurry layer 222 is attached to the side of the first slurry layer 221 opposite to the base layer 21. The catalyst 2 in this embodiment is a layered slurry structure catalyst 2, wherein the first slurry layer 221 includes an active material and a supporting material, and the second slurry layer 222 includes a molecular sieve material and an additive.

[0038] Whether it is a single-layer slurry structure or a layered slurry structure, the molecular sieve material includes one or more of Fe-CHA, Fe-BA, and Cu-CHA, the active material includes one or more of Pt and Rh, and the supporting material includes one or more of Al2O3 and TiO2.

[0039] Based on the above embodiments, the slurry layer 22 can adopt any one of the above structures or a combination of both. The catalyst 2 composed of the above components all have the catalytic ability to oxidize NH3. The slurry with the aforementioned structure is applied to the inner wall surface of the silencer hole 11, so that the front silencer 100 has the ability to process NH3.

[0040] Because gasoline vehicles generally have lower NH3 emissions than diesel vehicles, and emission levels vary significantly between different vehicles, their impact on AMO (Anti-Malfunction Influence) is relatively small. x The conversion efficiency requirement is relatively low; at 250℃, AMO x It is reasonable and necessary for the catalyst to have a conversion capacity of more than 50% for NH3.

[0041] For the active materials (precious metals Pt and Rh) in the slurry, the conversion performance of catalyst 2 for NH3 significantly improves with increasing active material content. When the precious metal content in the formulation is 0.005%, the conversion efficiency exceeds 50%. When the precious metal content in the formulation exceeds 1.0%, the overall NH3 conversion efficiency is already very high, and the effect of further increasing the precious metal content on the conversion efficiency gradually weakens. Therefore, the optimal conversion efficiency is achieved when the active material content is between 0.005% and 0.5%.

[0042] Furthermore, when the solid content of the catalyst 2 slurry is too low, the slurry is too thin, making it difficult to coat the inner wall of the silencer hole 11. When the solid content of the catalyst 2 slurry is too high, the slurry becomes too thick, affecting the conversion efficiency of the catalyst 2. Therefore, the solid content of the slurry layer 22 needs to be controlled within a certain range so that the catalyst 2 has good conversion efficiency while being easy to coat the inner wall of the silencer hole 11. Preferably, the solid content of the slurry layer 22 is 10%-45%. Catalyst 2 with a solid content of 10%-45% within this range can achieve optimal conversion efficiency.

[0043] Furthermore, the optimal conversion efficiency is achieved when the particle size D90 (i.e., all particles smaller than this size account for 90% of the total) during the preparation of catalyst 2 slurry is 5-30 μm.

[0044] The above description, based on the embodiments shown in the drawings, details the structure, features, and effects of this utility model. The above description is only a preferred embodiment of this utility model, but the scope of implementation of this utility model is not limited to what is shown in the drawings. Any changes made in accordance with the concept of this utility model, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and drawings, shall be within the protection scope of this utility model.

Claims

1. A front muffler, characterized in that, include: A muffler tube body, wherein the muffler tube body has multiple muffler holes; A catalyst for treating NH3 pollutants, the catalyst being coated on at least a portion of the inner wall surface of the silencing holes.

2. The front muffler according to claim 1, characterized in that, The thickness of the catalyst coating is 20-300 μm.

3. The front muffler according to claim 1, characterized in that, The catalyst comprises a base layer and a slurry layer, the slurry layer being attached to the base layer.

4. The front muffler according to claim 1, characterized in that, The catalyst includes a base layer and a slurry layer. The slurry layer includes a first slurry layer and a second slurry layer. The first slurry layer is attached to the base layer, and the second slurry layer is attached to the side of the first slurry layer opposite to the base layer.

5. The front muffler according to claim 3 or 4, characterized in that, The particle size D90 of the slurry layer is 5-30 μm.

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