CN111102037B

CN111102037B - Engine catalysis type particulate trap with amortization guiding device

Info

Publication number: CN111102037B
Application number: CN201911307605.4A
Authority: CN
Inventors: 左青松; 沈壮; 张彬; 张建平; 陈伟
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2019-12-18
Filing date: 2019-12-18
Publication date: 2021-11-12
Anticipated expiration: 2039-12-18
Also published as: CN111102037A

Abstract

The invention discloses an engine catalytic type particle trap with a noise-absorbing and guiding device. , Catalytic conversion part, gap structure, catalytic particle capture part, catalytic particle capture part shock absorption layer, first-level muffler perforated plate, second-level muffler perforated plate, shrink pipe, exhaust pipe, exhaust flange. The use of a new type of double-stage sleeve small-hole muffler pipe and a double-layer muffler perforated plate with dislocated small holes to improve the shape of the catalytic conversion part carrier can further optimize the exhaust gas purification and muffler post-treatment. It has the advantages of compact structure, good performance and stable operation. .

Description

Engine catalysis type particulate trap with amortization guiding device

Technical Field

The invention relates to the technical field of engine tail gas purification, in particular to an engine catalytic type particle trap with a silencing and flow guiding device.

Background

Along with the rapid advance of economic strength in China, the quality of life of people is continuously improved, the demand of people on motor vehicles is gradually increased, and the quantity of the motor vehicles to be kept is rapidly increased. Increasingly strict emission regulations put higher demands on engine emission control, and the emission of engine particles controlled by only an internal purification mode cannot meet the requirements of current emission standards and regulations, and a catalytic converter and a catalytic type particle trap are one of the most effective and most potential technologies for controlling the emission of pollutants and particles in the tail gas of an engine at present. Catalytic conversionThe device can purify pollutants such as HC and CO in the exhaust gas of the engine and convert NO in the exhaust gas into NO with strong oxidizing property₂. The catalytic type particle trap can realize the trapping of particles in the tail gas of an engine through a multi-pore channel structure, and NO is₂Continuously oxidize the particles in the filter body of the particle catcher, thereby realizing the regeneration of the catalytic particle catcher.

In urban noise pollution, the noise generated by motor vehicles accounts for a large proportion, and the noise brings great harm to daily life and health of people. In motor vehicle noise pollution, the exhaust system noise of the engine accounts for a large proportion. With the continuous development of engine technology, the engine speed and power are greatly improved, and the exhaust noise is larger and larger. Currently, the most effective method of controlling exhaust noise is to add an exhaust muffler after the engine.

In order to save the space of an exhaust aftertreatment system, a tail gas purification device and an exhaust noise control device of an engine can be organically combined and designed into an integrated structure, so that the dual functions of engine tail gas purification and exhaust noise control are realized. Therefore, the design and development of the catalytic type particulate trap of the engine, which has the advantages of compact structure, good performance and stable operation, have important significance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides an engine catalytic type particle trap with a silencing and flow guiding device, the integrated structural design can purify pollutants such as HC, CO, PM and the like in exhaust gas discharged by an engine, meanwhile, the exhaust noise of the engine is controlled by arranging the silencing structure, and meanwhile, the front silencing structure with a certain flow guiding effect can enable the exhaust gas in a catalytic conversion part carrier to be distributed more uniformly, so that the carrier utilization rate is improved, and the service life is prolonged.

The technical scheme adopted by the invention is as follows: the engine catalytic particle trap with the silencing and flow guiding device is used in an engine exhaust system, preferably, the engine catalytic particle trap with the silencing and flow guiding device is horizontally arranged in an assembly state, and is characterized in that structures such as a primary small hole silencing air inlet pipe, a secondary small hole silencing pipe, a catalytic conversion part damping layer, a catalytic conversion part, a gap structure, a catalytic particle trapping part damping layer, a primary silencing perforated plate and a secondary silencing perforated plate are arranged in a shell with a circular cross section.

The right side of the first-stage small-hole noise-reduction air inlet pipe is in a closed state, and a small hole is formed in the pipe wall in the shell; the axis of the second-stage small-hole silencing inlet pipe coincides with the axis of the first-stage small-hole silencing inlet pipe, small holes are formed in the pipe wall and the right side of the pipe wall, and the small holes of the first-stage small-hole silencing inlet pipe and the small holes of the second-stage small-hole silencing inlet pipe are uniformly distributed in the embodiment.

The catalytic conversion part of carriers are arranged in the radial and right areas of the secondary small-hole silencing pipe, the carrier areas are all porous media, the material of the carrier areas is sepiolite, and the surface of the carrier areas is coated with a noble metal catalyst.

The catalytic type particle trapping part is composed of a series of inlet and outlet channels which are continuously and alternately blocked, exhaust enters the trapping part from an inlet channel, particles are trapped through the wall surface of a porous medium, then airflow flows out from outlet channels distributed around the inlet channel, the porous medium carrier material of the catalytic type particle trapping part is sepiolite, and the surface of the porous medium carrier material is coated with a noble metal catalyst.

Further, the preparation material of the catalytic conversion part carrier porous medium carrier is sepiolite, and the preparation method comprises the following steps: soaking sepiolite in hydrochloric acid with the concentration of 1mol/L for treatment for 18h, drying and roasting to obtain acidic sepiolite, soaking the acidic sepiolite in a catalyst solution with a certain concentration for ultrasonic soaking treatment, and finally roasting at a high temperature and a constant temperature to obtain the catalyst-loaded sepiolite carrier.

The catalytic conversion section and the catalytic particulate trap section each have a spacing from the inner surface of the housing that may vary depending on the type and design of the device used. The space between the two layers is filled with a shock absorption layer which can provide elastic support for the catalytic conversion part and the catalytic type particle trapping part. The elastomeric damping layer provides both thermal insulation to the external environment and mechanical support to the fragile structure, thereby protecting the fragile structure from mechanical impact over a wide range of aftertreatment operating temperatures.

The closed space formed between the right side of the catalytic conversion part and the left side of the catalytic type particle trapping part is of a middle gap structure, and the width of the gap structure is 10-50 mm.

One-level amortization perforated plate and second grade amortization perforated plate arrange in catalysis type particle entrapment part right side, and evenly distributed has been put to the equipartition on one-level amortization perforated plate and the second grade amortization perforated plate aperture, and the aperture is the staggered arrangement on one-level amortization perforated plate and the second grade amortization perforated plate, and aperture axis does not all be on same straight line on one-level amortization perforated plate and the second grade amortization perforated plate promptly.

Furthermore, numerical simulation is carried out on an engine catalytic type particle trap model with a silencing and flow guiding device by using Fluent software, and guidance can be provided for the structural optimization design of the model.

Compared with the prior art, the invention has the beneficial effects that:

(1) the novel double-stage sleeve small-hole silencing pipe can effectively eliminate exhaust noise of an engine and simultaneously play a certain role in flow guiding, so that automobile exhaust in a catalytic conversion part of a carrier is distributed more uniformly, the utilization rate of the carrier is improved, and the service life of the carrier is prolonged;

(2) by improving the shape of the carrier of the catalytic conversion part, the contact area between the exhaust gas of the engine and the catalytic conversion part is increased, thereby improving the purification efficiency of pollutants such as HC, CO and the like in the exhaust gas of the engine and the conversion of NO to NO₂The conversion efficiency of (a);

(3) the double-layer silencing perforated plate with the staggered small holes is arranged, so that the back-and-forth reflection flow and energy attenuation of the tail gas of the engine are increased, and the aims of silencing and denoising are fulfilled;

(4) the catalytic conversion part and the catalytic type particle trapping part are connected in series, harmful gas in automobile exhaust emission can be effectively reduced, tiny particles in the exhaust can be trapped through mechanisms such as chemical reaction, adsorption, deposition, impact and the like, the emission concentration of pollutants in automobile exhaust is greatly reduced, and the porous medium characteristics of the carriers of the catalytic conversion part and the catalytic type particle trapping part also have certain effects on the aspect of further reducing exhaust noise;

(5) the exhaust gas purified by the catalytic conversion part can be redistributed to enter the catalytic type particle trapping part by arranging a certain gap structure between the right side of the catalytic conversion part and the left side of the catalytic type particle trapping part, so that the uniformity of the exhaust gas flow is effectively adjusted, and the particle trapping efficiency is improved;

(6) sepiolite with high thermal stability, high adsorptivity, large specific surface area, no toxicity and no radioactivity is used as a catalytic conversion part and a catalytic type particle trapping part carrier, so that the tail gas purification efficiency can be effectively improved;

(7) the integrated structure design of the exhaust purification and the noise elimination of the engine can be realized, the space structure of the exhaust aftertreatment system can be optimized and saved, and the integrated structure has the advantages of compact structure, good performance, stable operation and the like.

Drawings

FIG. 1 is a half-sectional view of an engine catalytic particulate trap with a sound-deadening flow-guiding device. In the figure: the device comprises an air inlet flange, a primary small hole silencing air inlet pipe, a secondary small hole silencing pipe, a shell, a catalytic conversion part damping layer, a catalytic conversion part, a gap structure, a catalytic particle trapping part damping layer, a primary silencing perforated plate, a secondary silencing perforated plate, a contraction pipe, a 13 exhaust pipe and an exhaust flange, wherein the primary small hole silencing air inlet pipe is 1, the secondary small hole silencing air inlet pipe is 2, the secondary small hole silencing pipe is 3, the shell is 4, the catalytic conversion part damping layer is 5, the catalytic conversion part damping layer is 6, the catalytic conversion part is 7, the gap structure is 8, the catalytic particle trapping part is 9, the catalytic particle trapping part damping layer is 10, the primary silencing perforated plate is 11, the secondary silencing perforated plate is 12, the contraction pipe is 13, and the exhaust flange is 14.

FIG. 2 is a flow pattern of internal passages of a filter body of a catalytic particle trap portion of an engine catalytic particle trap having a noise reduction and flow guide device.

FIG. 3 is a cloud diagram of a two-dimensional CFD simulated velocity vector distribution of a centerplane of an engine catalyzed particulate trap having a sound attenuating and flow directing device.

FIG. 4 is a cloud diagram of a two-dimensional CFD simulated pressure distribution of a center plane of an engine catalyzed particulate trap with a sound attenuating and flow directing device.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, an engine catalytic particle trap with a silencing and flow guiding device comprises an air inlet flange 1, a primary small hole silencing air inlet pipe 2, a secondary small hole silencing pipe 3, a shell 4, a catalytic conversion part damping layer 5, a catalytic conversion part 6, a gap structure 7, a catalytic particle trapping part 8, a catalytic particle trapping part damping layer 9, a primary silencing perforated plate 10, a secondary silencing perforated plate 11, a contraction pipe 12, an exhaust pipe 13 and an exhaust flange 14.

The right side of the first-stage small-hole noise-reduction air inlet pipe 2 is in a closed state, and a small hole is formed in the pipe wall in the shell 4; the axes of the second-level small-hole silencing pipe 3 and the first-level small-hole silencing air inlet pipe 2 are coincided, and small holes are formed in the pipe wall; the carriers of the catalytic conversion part 6 are arranged in the radial and right areas of the secondary small-hole silencing pipe 3, the carrier areas are porous media, the material of the carrier areas is sepiolite, and the surface of the carrier areas is coated with a noble metal catalyst; the catalytic type particle trapping part 8 is composed of a series of inlet and outlet channels which are continuously and alternately blocked as shown in figure 2, exhaust enters the trapping part from the inlet channels, particles are trapped through the wall surface of a porous medium, then airflow flows out from outlet channels distributed around the inlet channels, the porous medium carrier material of the catalytic type particle trapping part is sepiolite, and the surface of the porous medium carrier material is coated with a noble metal catalyst; the carriers of the catalytic conversion part 6 and the catalytic type particle trapping part 8 are respectively spaced from the inner surface of the shell 4 by a certain distance, and the distance is filled with the damping layer 5 of the catalytic conversion part or the damping layer 9 of the catalytic type particle trapping part; the closed space formed between the right side of the catalytic conversion section 6 and the left side of the catalytic type particulate trapping section 8 is a middle gap structure 7; one-level amortization perforated plate 10 and second grade amortization perforated plate 11 arrange in the 8 right sides of catalysis type particle entrapment part, and evenly distributed's aperture has been put to one-level amortization perforated plate 10 and second grade amortization perforated plate 11, and aperture is the dislocation arrangement on one-level amortization perforated plate 10 and the second grade amortization perforated plate 11, installs shrink tube 12 and blast pipe 13 thereafter.

The working principle is as follows: the high-speed tail gas air current of engine's exhaust flows into one-level aperture amortization intake pipe 2, because one-level aperture amortization intake pipe 2 right side is sealed, tail gas flows into second grade aperture amortization pipe 3 through one-level aperture amortization intake pipe 2 circumference aperture and flows through catalytic conversion part 6 after carrying out amortization water conservancy diversion processing, catalytic conversion part 6 can purify pollutants such as HC, CO in the engine exhaust, simultaneously with the NO conversion formation in the exhaust have the NO of strong oxidizing property₂The purified tail gas flows into the catalytic particle trapping part 8 after flowing through the gap structure 7 and redistributing the airflow, the tail gas flows into the filter element inlet channels arranged at intervals, after the exhaust gas enters from the filter element inlet channels, because the inlet channels are blocked by the inlet channel plugs at the right side, and the outlet channels are blocked by the outlet channel plugs at the left side, the exhaust gas can only pass through the porous medium wall surfaces between the channels and flows out from the adjacent other channel, namely the filter element outlet channel, in the process, the particulate matters (soot) in the exhaust gas are deposited on the porous medium wall surfaces of the inlet channels serving as the filter materials, the trapping function of the particulate matters in the exhaust gas is realized, and meanwhile, the particulate matters and NO are subjected to the trapping function₂The reaction occurs, the catalytic particle trapping part 8 is regenerated, and finally, the clean tail gas is silenced by the first-stage silencing perforated plate 10 and the second-stage silencing perforated plate 11 and then is discharged from the exhaust pipe 13.

The numerical simulation is carried out on an engine catalytic type particle trap model with a silencing and flow guiding device by using Fluent software, guidance can be provided for the structural optimization design, a figure 3 is a two-dimensional CFD simulation velocity vector distribution cloud picture of a central plane of the engine catalytic type particle trap with the silencing and flow guiding device, a figure 4 is a two-dimensional CFD simulation pressure distribution cloud picture of the central plane of the engine catalytic type particle trap with the silencing and flow guiding device, the layering of the flow velocity is less in the sepiolite carrier of a catalytic conversion part, most of fluid passes through the whole sepiolite carrier at a uniform flow velocity, and the novel silencing and flow guiding device can effectively adjust the flow direction and the flow velocity of the engine exhaust before entering the catalytic conversion part, improve the radial exhaust distribution and enable the fluid in the sepiolite carrier to flow integrally uniformly, the expected optimization effect is achieved.

Claims

1. An engine catalyzed particulate trap with a sound-absorbing and air-guiding device, characterized in that it is composed of an intake flange (1), a first-level small hole sound-absorbing intake pipe (2), and a second-level small hole sound-absorbing pipe (3) , shell (4), catalytic conversion part damping layer (5), catalytic conversion part (6), gap structure (7), catalytic particle trapping part (8), catalytic particle trapping part damping layer ( 9), composed of a first-level sound-absorbing perforated plate (10), a second-level sound-absorbing perforated plate (11), a shrinking pipe (12), an exhaust pipe (13), and an exhaust flange (14); the first-level small hole silencer A small hole is opened on the pipe wall of the air inlet pipe (2) in the casing (4), and the right side is in a closed state; the secondary small hole muffler pipe (3) is provided with small holes on the pipe wall and the right side , and coincides with the axis of the first-stage small hole muffler intake pipe (2); the second-stage small hole muffler pipe (3) is covered on the outer periphery of the first-stage small hole muffler intake pipe (2), and the second-stage small hole muffler pipe ( 3) It is not connected in the axial direction with the first-stage small hole muffler intake pipe (2);

The catalytic conversion part carrier is arranged in the radial and right regions of the secondary small hole muffler pipe (3); a hole; the gap structure (7) is arranged between the right side of the catalytic conversion part (6) and the left side of the catalytic particle trapping part (8), and the axial length is 10-50mm;

The high-speed exhaust gas flow of the engine's exhaust flows into the first-stage small hole muffler intake pipe (2). Since the right side of the first-stage small hole muffler intake pipe (2) is closed on the right side, the exhaust gas passes through the first-stage small hole muffler intake pipe (2). The circumferential small holes After flowing into the secondary small hole muffler pipe (3) for noise reduction and diversion treatment, it flows through the catalytic conversion part (6). The NO in the medium is converted into NO ₂ with strong oxidizing property. The purified exhaust gas flows through the gap structure (7) for redistribution and then flows into the catalytic particle trapping part (8), and the exhaust gas flows into the inlets of the filter elements arranged at intervals. After the exhaust gas enters from the inlet channel of the filter element, the inlet channel is blocked by the inlet channel plug on the right side, and the outlet channel is blocked by the outlet channel plug on the left side, so that the exhaust gas can only pass through the porous holes between the channels. The wall surface of the medium flows out from another adjacent channel, that is, the outlet channel of the filter element. During this process, the particulate matter in the exhaust gas is deposited on the wall surface of the porous medium of the inlet channel as the filter material, so as to realize the removal of the particulate matter in the exhaust gas. At the same time, the particulates react with NO ₂ , the catalytic particulate trapping part (8) is regenerated, and finally the clean exhaust gas is silenced through the first-level muffler perforated plate (10) and the second-level muffler perforated plate (11). Then it is discharged from the exhaust pipe (13).

2 . An engine catalytic particulate trap with a noise-absorbing and diversion device according to claim 1 , wherein the catalytic conversion part ( 6 ) and the catalytic particulate trap part ( 8 ) have the same carrier raw materials. 3 . For sepiolite.