CN105781689B - Diesel engine vent gas compound noise-reducing device - Google Patents

Abstract

The invention discloses a composite noise reduction device for diesel engine exhaust, which comprises a catalytic oxidation device, a particle trapping device fixed on the exhaust end of the catalytic oxidation device for absorbing and filtering PM particles, and an exhaust port fixed on the particle trapping device Exhaust muffler; the catalytic oxidation device includes a first housing and a purification catalyst carrier; the particle trapping device includes a second housing and a honeycomb ceramic carrier; the exhaust muffler includes a third housing and a stepped variable diameter exhaust pipe; the stepped variable diameter exhaust pipe includes a first-order exhaust pipe, a second-order exhaust pipe and a third-order exhaust pipe whose pipe diameter becomes smaller in turn and inserted into the arrangement; the diesel engine exhaust compound reducer of the present invention Noise device, compact structure, reasonable use of space, not only can filter and purify the exhaust gas, but also can better eliminate multi-frequency noise, realize the joint work of exhaust gas purification and noise reduction, simple structure, low cost, long service life, easy to install and disassembly; exhaust gas purification and muffler efficiency is high.

Description

Diesel engine exhaust composite noise reduction device

technical field

The invention relates to an exhaust noise reduction device, in particular to a diesel engine exhaust composite noise reduction device.

Background technique

According to the national development strategy of energy conservation and emission reduction and the national requirements to deal with greenhouse gas emissions, there is an urgent need to carry out projects for exhaust gas recovery and purification of diesel engines and generator power equipment used in engineering construction, and exhaust noise reduction projects to reduce emissions and achieve the purpose of energy conservation and emission reduction. It is closely integrated with production and engineering to improve the quality of life and normal operation of production.

Exhaust gas treatment and noise reduction of diesel engines in the prior art are exhaust gas purification devices and mufflers working alone; performance and efficiency are relatively low; the main principle of mufflers currently used for diesel engines is to use porous sound-absorbing materials to reduce noise. The sound-absorbing material is fixed on the inner wall of the airflow channel or arranged in a certain way in the pipeline to form a resistive muffler, which has a poor effect on low-frequency noise reduction, and the diesel engine exhaust contains more toxic gases and the PM content is too high. The environmental pollution is serious, and the tail gas treatment system composed of a separately installed catalytic oxidation converter and a particulate trap is relatively large, inconvenient to install and use, complex in structure, and not strong in pertinence.

Contents of the invention

In view of this, the purpose of the present invention is to provide a diesel engine exhaust compound noise reduction device, which has a compact structure and reasonable space utilization, can not only filter and purify the exhaust gas, but also can better eliminate multi-frequency noise, and realize exhaust gas purification and noise reduction. Noise and noise work together, simple structure, low cost, long service life, easy installation and disassembly; high exhaust gas purification and noise reduction efficiency.

The diesel engine exhaust composite noise reduction device of the present invention comprises a catalytic oxidation device, a particle trapping device fixed on the exhaust end of the catalytic oxidation device for absorbing and filtering PM particles, and an exhaust muffler fixed on the exhaust end of the particle trapping device The catalytic oxidation device includes a first housing provided with an air inlet and an exhaust port and a purification catalyst carrier fixed in the first housing; a catalyst is loaded on the purification catalyst carrier; the particle trapping device includes a second housing body and a honeycomb ceramic carrier fixed in the second casing; the second casing is fixed to the exhaust port of the first casing and communicates with the first casing; the exhaust muffler includes an air inlet and The third casing of the exhaust port and the stepped variable-diameter exhaust pipe that is fixed in the third casing and communicates with the air inlet of the third casing to the exhaust port; the stepped variable-diameter exhaust pipe includes a pipe diameter The first-stage exhaust pipe, the second-stage exhaust pipe and the third-stage exhaust pipe which are successively smaller and inserted into the arrangement; the air inlet of the third casing is fixed to the particle trapping device.

Further, the stepped exhaust pipe with reduced diameter is fixed to the inner wall of the third housing through an annular plate assembly, and the annular plate assembly includes a first annular plate and a second annular plate axially arranged along the stepped exhaust pipe with reduced diameter , the third annular plate and the fourth annular plate; the first annular plate is arranged in the front part of the first-stage exhaust pipe; the second annular plate is arranged at the rear end of the second-stage exhaust pipe so that the second annular plate and the first annular plate The second resonant cavity is formed between them; the third annular plate is arranged in the middle of the third-stage exhaust pipe to form a third resonant cavity between the third annular plate and the second annular plate, and the fourth annular plate is arranged on the third-stage exhaust pipe The middle rear portion of the fourth ring plate forms a fourth resonance cavity between the third ring plate and the fourth ring plate.

Further, the rear end of the first-stage exhaust pipe and the second-stage exhaust pipe are connected and sealed by an annular sealing plate; a second resonance chamber and a fourth resonance chamber are fixed between the second annular plate and the third annular plate. The micro-perforated exhaust pipe of the cavity; the expanded perforated exhaust pipe connecting the third resonant cavity and the fourth annular plate to the exhaust port of the third housing is fixed between the third annular plate and the fourth annular plate. pipe; the part of the first-stage exhaust pipe and the second-stage exhaust pipe corresponding to the second resonant cavity, the part of the micro-perforated exhaust pipe corresponding to the third resonant cavity, and the third-stage exhaust pipe corresponding to the fourth resonant cavity The part of the expanded perforated exhaust pipe and the part corresponding to the fourth resonant cavity are all provided with a plurality of micropores uniformly distributed along the corresponding pipe wall.

Further, the first annular plate and the third annular plate are provided with flow-through holes front and rear; the rear side of the fourth annular plate is fixed with a valve communicating with the fourth resonant cavity and guiding the airflow to the third housing. The elbow of the exhaust port; there are multiple elbows, some of which are set corresponding to the expansion perforated exhaust pipe, and the front ends of the remaining elbows, the expanded perforated exhaust pipe and the micro-perforated exhaust pipe are all provided with forward-extending The expansion exhaust pipe; the diameter of the elbow pipe is larger than the diameter of the corresponding expansion perforated exhaust pipe or expansion exhaust pipe.

Further, the honeycomb ceramic carrier includes a honeycomb body with a plurality of air channels arranged in parallel, and a baffle plate fixed in each air channel in an offset manner corresponding to any two adjacent air channels; the honeycomb body is separated from any The portion between two adjacent air passages is provided with a cordierite filter layer.

Further, a liner is provided between the honeycomb ceramic carrier and the second shell.

Further, the first housing is provided with a first resonance cavity corresponding to the side of the purification catalyst carrier, and the opening of the first resonance cavity faces the purification catalyst carrier.

Further, the part of the first casing corresponding to its own air inlet to the purification catalyst carrier is a tapered structure whose cross-section gradually becomes larger along the airflow direction.

Further, the first resonant chamber is multiple and closely arranged around the side of the purification catalyst carrier; the first resonant chamber is surrounded by an inner cylinder arranged in the first housing and a partition fixed between the inner cylinder and the first housing The baffle includes an annular baffle arranged along the circumference of the inner cylinder and a longitudinal baffle parallel to the axis of the inner cylinder; the annular baffle and the longitudinal baffle are fixed together in a criss-cross pattern, and the mouth of the first resonant cavity It is arranged on the inner cylinder and has a circular necking structure.

The beneficial effects of the present invention are: the diesel engine exhaust composite noise reduction device of the present invention has a compact structure and reasonable use of space, can not only filter and purify the exhaust gas, but also can better eliminate multi-frequency noise, and realize the combination of exhaust gas purification and noise reduction. Working, simple structure, low cost, long service life, easy to install and disassemble; exhaust gas purification and noise reduction efficiency is high.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a partial perspective view of the exhaust muffler;

Fig. 3 is a schematic diagram of the structure of the particulate trapping device;

Fig. 4 is a partial perspective view of the particulate trapping device.

Detailed ways

Fig. 1 is a schematic structural view of the present invention; Fig. 2 is a partial perspective view of an exhaust muffler; Fig. 3 is a schematic structural view of a particulate trapping device; Fig. 4 is a partial perspective view of a particulate trapping device, as shown in the figure: the present embodiment Diesel engine exhaust recovery purification and noise reduction compound device, including catalytic oxidation device, particulate trapping device and exhaust muffler; said catalytic oxidation device includes a first housing 1 with an air inlet and an exhaust port and fixed on the first The purification catalyst carrier 2 in the housing 1; the catalyst carrier 2 is loaded with catalyst; the first housing 1 is provided with a first resonance cavity 3 corresponding to the purification catalyst carrier 2 side and the opening of the first resonance cavity 3 faces the purification catalyst Carrier 2; the particulate trapping device is fixed to the exhaust port of the first housing 1 for absorbing and filtering PM particles; the exhaust muffler is fixed to the exhaust end of the particulate trapping device; the particulate trapping device Comprising a second shell 6 and a honeycomb ceramic carrier fixed in the second shell 6; the second shell 6 is fixed to the exhaust port of the first shell 1 and communicated with the first shell 1; the The exhaust muffler includes a third housing 10 with an air inlet and an exhaust port, and a stepped variable-diameter exhaust pipe that is fixed in the third housing 10 and connects the air inlet of the third housing 10 to the exhaust port. pipe; the diameter of the inlet end of the stepped variable-diameter exhaust pipe is greater than the diameter of the exhaust end, and the stepped variable-diameter exhaust pipe includes a first-stage exhaust pipe 11, a second-stage row exhaust pipe 11, and a second-stage exhaust pipe with pipe diameters that become smaller in turn and plugged in. The air pipe 12 and the third-stage exhaust pipe 13; the air inlet of the third housing 10 is fixed to the particulate trapping device; the second-stage exhaust pipe 12 is inserted into the outlet of the first-stage exhaust pipe 11, and the third-stage exhaust pipe 13 Insert the outlet of the second-stage exhaust pipe 12, adopt the insertion pipe structure combined with the sudden change of the section to make the acoustic impedance change suddenly, so as to realize interference cancellation, achieve the purpose of eliminating middle and low frequency noise, and realize the joint work of exhaust gas treatment and noise reduction, with a simple structure , low cost, long service life, easy installation and disassembly, high noise reduction efficiency, low back pressure, core technology is universal and can be modified and applied in similar fields; catalytic oxidation device, particle trapping device and exhaust muffler The three are connected together through a flange structure, which is easy to install and disassemble. Each part works independently and has high efficiency. Working together can achieve mutual promotion, so that exhaust gas treatment and noise reduction can be realized at the same time, which greatly improves the efficiency of purification and noise reduction; diesel engine Exhaust gas flows from the air inlet of the first housing 1 to the exhaust port of the first housing 1 through the purification catalyst carrier 2. The purification catalyst carrier 2 is fixed on the inner wall of the first housing 1. The side surface of the purification catalyst carrier 2 refers to Purify the surface of the connection between the catalyst carrier 2 and the first housing 1, and set the first resonant chamber 3 on the side of the first housing 1 corresponding to the purified catalyst carrier 2. The structure is compact and the space utilization is reasonable. The catalytic oxidation converter DOC and the resonant chamber chambers, the purification catalyst carrier is provided with a plurality of channels arranged side by side, and a titanium-silicon catalyst is fixed between the channels. The purification catalyst carrier is a network structure composed of cordierite, forming dense channels, and the diameter of cordierite is 40-100nm. The titanium-silicon catalyst is fixed between the channels, that is, the titanium-silicon catalyst is fixed on the carrier structure separated between adjacent channels. In the structure, the catalyst is not easy to leak, stable and adaptable; when the exhaust gas flows through the 2 channels of the DOC purification catalyst carrier, the HC and other substances in it enter the active layer from the main air flow area of the 2 channels of the purification catalyst carrier, and are adsorbed on the carrier The surface of the active layer of cordierite (magnesium aluminosilicate) coated on the wall of the channel forms complexes, and the complexes undergo a catalytic reaction under the action of a titanium-silicon catalyst. The surface desorbs, and finally enters the PM control area from the diffusion channel in the form of reverse diffusion; the sound wave diffuses into the first resonant cavity 3, and the friction and heat dissipation of the cavity wall and the resonance in the cavity cancel the sound energy, thereby reducing the low-frequency noise , and can alleviate the impact of the airflow on the first shell 1, further reduce the noise, and achieve the purpose of not only catalyzing and oxidizing harmful gases, but also eliminating middle and low frequency noise.

In this embodiment, the stepped variable-diameter exhaust pipe is fixed to the inner wall of the third housing 10 through an annular plate assembly, and the annular plate assembly includes a first annular plate 14 arranged axially along the stepped variable-diameter exhaust pipe , the second annular plate 15, the third annular plate 16 and the fourth annular plate 17; the first annular plate 14 is arranged on the front part of the first-stage exhaust pipe 11; the second annular plate 15 is arranged on the second-stage exhaust pipe 12 The rear end forms the second resonant cavity between the second annular plate 15 and the first annular plate 14; the third annular plate 16 is arranged in the middle part of the third-stage exhaust pipe 13 so that The third resonant cavity is formed between them, and the fourth annular plate 17 is arranged at the middle and rear part of the third-stage exhaust pipe 13 so that the fourth resonant cavity is formed between the fourth annular plate 17 and the third annular plate 16, so that the gas flows in each resonant cavity. Friction, collision and interference reactions are carried out in the middle, and the sound energy is converted into heat energy, thereby eliminating high-frequency noise. At the same time, each annular plate provides a stable and reliable installation structure for the stepped variable-diameter exhaust pipe. The impact of the airflow on the third casing 10 can be alleviated, and the noise can be further reduced.

In this embodiment, the rear end of the first-stage exhaust pipe 11 and the second-stage exhaust pipe 12 are connected and sealed by an annular sealing plate; The micro-perforated exhaust pipe 18 of the second resonant cavity and the fourth resonant cavity; a row connecting the third resonant cavity and the fourth annular plate 17 to the third housing 10 is fixed between the third annular plate 16 and the fourth annular plate 17 The expanded perforated exhaust pipe 19 of the chamber between the gas ports; the part corresponding to the first-stage exhaust pipe 11 and the second-stage exhaust pipe 12 and the second resonance chamber, and the micro-perforated exhaust pipe 18 is connected to the third resonance chamber The corresponding part, the part of the third-stage exhaust pipe 13 corresponding to the fourth resonance cavity, and the part of the expanded perforated exhaust pipe 19 corresponding to the fourth resonance cavity are all provided with a plurality of micropores 20 uniformly distributed along the corresponding pipe wall , so that the stepped variable-diameter exhaust pipe communicates effectively with the second resonant cavity, the third resonant cavity and the fourth resonant cavity, as well as between each cavity through micropores 20 or pipes, and the friction when the gas expands through the hole wall Dissipate heat and consume sound energy.

In this embodiment, the first annular plate 14 and the third annular plate 16 are provided with flow-through holes 21 through front and rear; the rear side of the fourth annular plate 17 is fixed with a The air flow guides the elbow 22 of the exhaust port of the third housing 10; there are multiple elbows 22, some of which are arranged corresponding to the expanded perforated exhaust pipe 19, and the remaining elbows 22 and each expanded perforated exhaust pipe 19 and micro-perforated exhaust pipe 18 front ends are all provided with the expansion exhaust pipe 23 that protrudes forward; The air flow from the exhaust pipe 19 and the expansion exhaust pipe 23 into the elbow 22 results in a sudden change in acoustic impedance by means of a sudden change in section, and uses the principle of interference cancellation to eliminate part of the noise. The air flow on both sides of the first annular plate 14 and the third annular plate 16 To a certain extent, it can flow through the flow hole 21 to improve the balance of the system. When the gas expands and passes through the hole wall, it frictionally dissipates heat and consumes sound energy. The exhaust port of the elbow 22 is designed as a 60° convection structure so that the rear end The remaining part of the noise uses the convection mechanism to interact, and the multi-frequency noise is reduced through molecular collision and interference cancellation. Finally, the large air flow performance of the stepped variable-diameter exhaust pipe is used to make the gas discharged from the elbow 22 flow in the main exhaust pipe. Under the action of the airflow, it flows to the exhaust port of the third casing 10 to be discharged, which ensures that the gas is not blocked and achieves better circulation.

In this embodiment, the honeycomb ceramic carrier includes a honeycomb body 7 with multiple air passages arranged in parallel and juxtaposed, and a baffle plate 8 fixed in each air passage corresponding to any two adjacent air passages in an offset manner; The partition between any two adjacent air passages in the honeycomb body 7 is a cordierite filter layer, and the flow of the air flow in the corresponding air passage can be cut off by the baffle plate 8, so the air flow entering the honeycomb body 7 passes through under the blocking effect of the baffle plate 8. Pass through the cordierite filter layer between two adjacent air passages and enter the adjacent air passages to achieve effective filtration of all airflows with high purification efficiency. Multiple baffles 8 can be set in the air passages to allow the airflow to pass through the adjacent air passages multiple times. The wall between the channels is filtered, and the particles are deposited in the honeycomb ceramic carrier by using the mechanism of diffusion, interception and inertial collision. When the particles accumulate at a certain position of the port, since the position just reaches the combustion value point of the particles, plus This device is applied to a large diesel engine. The temperature of the exhaust gas flowing through the particulate trapping device is higher than the ignition temperature of the particulates, so the combustion of the particulates can be directly realized at the port position, thereby realizing the regeneration of the particulate trapping device and ensuring the normal operation of the particulate trapping device. working status.

In this embodiment, a liner 9 is provided between the honeycomb ceramic carrier and the second housing 6, which not only improves the stability of the installation structure of the honeycomb ceramic carrier, but also can buffer the honeycomb ceramic carrier and the second housing 6. The vibration and shock between can reduce noise and reduce equipment failure rate.

In this embodiment, the part of the first housing 1 corresponding to its own air inlet to the purification catalyst carrier 2 is a conical structure with a cross-section gradually increasing along the airflow direction, forming a sudden expansion chamber, which is caused by a sudden change in section. Acoustic impedance mutation, using the principle of interference cancellation to eliminate part of the low-frequency intake noise.

In this embodiment, the first resonant cavity 3 is multiple and closely arranged around the side of the purification catalyst carrier 2; The partition 5 between the first housing 1 is surrounded; the partition 5 includes an annular partition arranged along the circumference of the inner cylinder 4 and a longitudinal partition parallel to the axis of the inner cylinder 4; the annular partition and the longitudinal partition It is fixed together in a criss-cross pattern. The mouth of the first resonant cavity 3 is set on the inner cylinder 4 and has a circular necking structure. The first resonant cavity 3 is a plurality of small cavity structures closely arranged, which can better To achieve resonance cancellation and further reduce low-frequency noise, the first resonance cavity 3 is formed by separating the gap between the first shell 1 and the inner cylinder 4 by using a partition 5, and the purification catalyst carrier 2 is fixed on the inner wall of the inner cylinder 4; The narrow-mouthed structure means that the mouth of the first resonant cavity 3 is smaller than the cross-section of the first resonant cavity 3, so that the first resonant cavity 3 forms a structure with a small cavity and a wide interior; the partition 5 can also be the following structure: comprising The spiral partition arranged in the circumferential direction of the inner cylinder 4 and the longitudinal partition parallel to the axis of the inner cylinder 4; the spiral partition is integrally formed with the inner cylinder 4; the longitudinal partition is integrally formed with the first shell 1, and Multiple slots for screwing in the spiral partition, the distance between the slots is equal to the pitch of the spiral partition, the overall structural strength is high, and it is easy to process. When assembling, the inner cylinder 4 is screwed into the first shell 1, and the operation The structure is simple and stable, and the gap between the inner cylinder 4 and the first casing 1 is divided into the first resonance cavity 3 by using the spiral partition and the longitudinal partition.

In this embodiment, the wall surface of the pores of the purification catalyst carrier 2 is coated with cordierite to form an active layer, so that the cordierite is evenly distributed, and a better catalytic oxidation effect is achieved through the diffusion mechanism, so that the air flow passes through the pores in the purification catalyst carrier 2 At the same time, the purpose of catalytic oxidation conversion of exhaust gas can be achieved.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (6)

1. A composite noise reduction device for diesel engine exhaust, characterized in that: it comprises a catalytic oxidation device, a particulate trapping device fixed to the exhaust end of the catalytic oxidation device for adsorbing and filtering PM particles, and an exhaust device fixed to the particulate trapping device. Gas end exhaust muffler; the catalytic oxidation device includes a first housing with an air inlet and an exhaust port and a purification catalyst carrier fixed in the first housing; a catalyst is loaded on the purification catalyst carrier; the particle trapping The device includes a second casing and a honeycomb ceramic carrier fixed in the second casing; the second casing is fixed at the exhaust port of the first casing and communicates with the first casing; the exhaust muffler includes a device There is a third casing with an air inlet and an exhaust port, and a stepped variable-diameter exhaust pipe that is fixed in the third casing and communicates with the air inlet of the third casing to the exhaust port; the stepped variable-diameter row The air pipe includes a first-stage exhaust pipe, a second-stage exhaust pipe, and a third-stage exhaust pipe whose pipe diameters become smaller in turn and are plugged in; the air inlet of the third housing is fixed to the particle trapping device; the honeycomb The ceramic carrier includes a honeycomb body with a plurality of air channels arranged in parallel and a baffle fixed in each air channel corresponding to any two adjacent air channels; the honeycomb body is separated between any adjacent two air channels The middle part is provided with a cordierite filter layer; the first housing is provided with a first resonance cavity corresponding to the side of the purification catalyst carrier, and the mouth of the first resonance cavity faces the purification catalyst carrier; the first resonance cavity is multiple and Closely arranged around the side of the purification catalyst carrier; the first resonance chamber is surrounded by an inner cylinder arranged in the first casing and a partition fixed between the inner cylinder and the first casing; the partition includes a The annular partition and the longitudinal partition parallel to the axis of the inner cylinder are set; the annular partition and the longitudinal partition are fixed together in a cross pattern, and the opening of the first resonance cavity is set on the inner cylinder and is of circular necking type structure. 2. The composite noise reduction device for diesel engine exhaust according to claim 1, characterized in that: the stepped variable diameter exhaust pipe is fixed to the inner wall of the third housing through an annular plate assembly, and the annular plate assembly includes a stepped The first annular plate, the second annular plate, the third annular plate and the fourth annular plate are axially arranged in the reducing exhaust pipe; the first annular plate is arranged at the middle front of the first-stage exhaust pipe; The rear end of the second-stage exhaust pipe forms a second resonant cavity between the second annular plate and the first annular plate; the third annular plate is arranged in the middle of the third-stage exhaust pipe to make the gap between the third annular plate and the second annular plate The third resonant cavity is formed between them, and the fourth annular plate is arranged at the middle and rear part of the third-stage exhaust pipe so that a fourth resonant cavity is formed between the fourth annular plate and the third annular plate. 3. The composite noise reduction device for diesel engine exhaust according to claim 2, characterized in that: the rear end of the first-stage exhaust pipe and the second-stage exhaust pipe are connected and sealed by an annular sealing plate; the second annular plate A micro-perforated exhaust pipe communicating with the second resonant cavity and the fourth resonant cavity is fixed between the third annular plate and the third annular plate; Expansive perforated exhaust pipes of the chamber between the exhaust ports of the third shell; the first-order exhaust pipe and the second-order exhaust pipe correspond to the second resonance cavity, the micro-perforated exhaust pipe and the third resonance The portion corresponding to the cavity, the portion of the third-stage exhaust pipe corresponding to the fourth resonant cavity, and the portion of the expanded perforated exhaust pipe corresponding to the fourth resonant cavity are all provided with a plurality of micropores uniformly distributed along the corresponding pipe wall. 4. The compound noise reduction device for diesel engine exhaust according to claim 3, characterized in that: the first annular plate and the third annular plate are provided with front and rear through holes; the rear of the fourth annular plate An elbow that communicates with the fourth resonance cavity and guides the airflow to the exhaust port of the third housing is fixed on the side; there are multiple elbows, some of which are set corresponding to the expanded perforated exhaust pipe, and the remaining elbows and the expansion The front ends of the perforated exhaust pipe and the micro-perforated exhaust pipe are all provided with an expanded exhaust pipe protruding forward; the diameter of the bent pipe is larger than that of the corresponding expanded perforated exhaust pipe or expanded exhaust pipe. 5. The composite noise reduction device for diesel engine exhaust according to claim 1, characterized in that: a liner is provided between the honeycomb ceramic carrier and the second housing. 6. The composite noise reduction device for diesel engine exhaust according to claim 1, characterized in that: the part of the first housing corresponding to its own air inlet to the purification catalyst carrier is a cross-section gradually increasing along the airflow direction Conical structure.