CN105781689B

CN105781689B - Diesel engine vent gas compound noise-reducing device

Info

Publication number: CN105781689B
Application number: CN201610216549.3A
Authority: CN
Inventors: 胡启国; 何燕飞; 李尚平; 李小兵; 袁玉峰; 赵桢
Original assignee: Chongqing Jiaotong University
Current assignee: Chongqing Jiaotong University
Priority date: 2016-04-08
Filing date: 2016-04-08
Publication date: 2018-06-22
Anticipated expiration: 2036-04-08
Also published as: CN105781689A

Abstract

The invention discloses a kind of diesel engine vent gas compound noise-reducing device, including catalytic oxidizing equipment, the exhaust end of catalytic oxidizing equipment is fixed on for adsorbing and filter the microparticles collection device of PM particles and be fixed on the exhaust end exhaust silencer of microparticles collection device；The catalytic oxidizing equipment includes first shell and catalyst carrier for purifying；The microparticles collection device includes second shell and cellular structure ceramic carrier；The exhaust silencer includes third housing and staged reducing exhaust pipe；The staged reducing exhaust pipe includes single order exhaust pipe, second order exhaust pipe and the three rank exhaust pipes that caliber becomes smaller successively and plug-in type is set；The diesel engine vent gas compound noise-reducing device of the present invention, compact-sized, space utilization is reasonable, can tail gas is filtered and be purified, multifrequency time noise can be preferably eliminated again, realize that tail gas clean-up and noise reduction work together, it is simple in structure, at low cost, service life is long, is easily installed and dismantles；Tail gas clean-up and acoustical absorptivity are high.

Description

Diesel engine vent gas compound noise-reducing device

Technical field

The present invention relates to exhaust purification noise device more particularly to a kind of diesel engine vent gas compound noise-reducing devices.

Background technology

According to the development strategy of national energy-saving emission reduction and the requirement of country's reply greenhouse gas emission, it is badly in need of carrying out engineering The project that construction diesel engine and the purification of generator power equipment tail gas recycle and exhaust noise reduce, to reduce discharge, is realized The purpose of energy-saving and emission-reduction is tightly combined with production and engineering, improves the quality of living and produce normal operation.

Diesel engine vent gas processing and noise reduction are all that exhaust gas cleaner and silencer work independently in the prior art；Unilaterally Performance and less efficient；Currently used for the muffler of diesel engine, its cardinal principle is to be made an uproar using sound-absorbing porous material to reduce Sound is fixed on sound-absorbing material on the inner wall of gas channel or is arranged in the duct according to certain way, just constitutes resistive disappear Sound device, it is poor to low frequency noise elimination effect, and diesel engine vent gas containing toxic gas it is more, PM contents are too high, environmental pollution compared with Seriously, it is more huge that the exhaust treatment system formed is combined with separately installed catalysis oxidation converter and microparticles collection device, Inconvenience is installed and used, complicated, specific aim is not strong.

Invention content

In view of this, the object of the present invention is to provide a kind of diesel engine vent gas compound noise-reducing devices, compact-sized, space profit With reasonable, tail gas can be filtered and purified and preferably eliminate multifrequency time noise, realize that tail gas clean-up and noise reduction are total to With work, simple in structure, at low cost, service life is long, is easily installed and dismantles；Tail gas clean-up and acoustical absorptivity are high.

The diesel engine vent gas compound noise-reducing device of the present invention, including catalytic oxidizing equipment, is fixed on catalytic oxidizing equipment Exhaust end disappears for adsorbing and filtering the microparticles collection device of PM particles and be fixed on the exhaust end exhaust of microparticles collection device Sound device；The catalytic oxidizing equipment includes the first shell equipped with air inlet and exhaust outlet and is fixed on net in first shell Change catalyst carrier；Supported catalyst on catalyst carrier for purifying；The microparticles collection device includes second shell and is fixed on Cellular structure ceramic carrier in second shell；The second shell be fixed on the exhaust outlet of first shell and with first shell phase It is logical；The exhaust silencer includes the third housing equipped with air inlet and exhaust outlet and is fixed in third housing and connects the The air inlet of three housings to exhaust outlet staged reducing exhaust pipe；The staged reducing exhaust pipe becomes smaller successively including caliber And single order exhaust pipe, second order exhaust pipe and the three rank exhaust pipes of plug-in type setting；The air inlet of third housing is fixed on particle Capturing device.

Further, the staged reducing exhaust pipe is fixed on third inner walls, the annular by annular slab component Plate component includes the first annular plate, the second annular slab, third annular slab and the 4th along staged reducing exhaust pipe axial alignment Annular slab；First annular plate is set on single order exhaust pipe middle front part；The rear end that second annular slab is set on second order exhaust pipe makes the second ring The second resonant cavity is formed between shape plate and first annular plate；Third annular slab, which is set in the middle part of three rank exhaust pipes, makes third annular slab Between the second annular slab formed third resonant cavity, fourth annular plate be set on three rank exhaust pipes middle and back make fourth annular plate with The 4th resonant cavity is formed between third annular slab.

Further, it connects and seals by ring sealing plate between the rear end of the single order exhaust pipe and second order exhaust pipe；The The micropunch exhaust pipe of the second resonant cavity of connection and the 4th resonant cavity is fixed between second ring plate and third annular slab；Third ring Connection third resonant cavity and fourth annular plate are fixed between shape plate and fourth annular plate between the exhaust outlet of third housing The expansion perforated exhaust pipe of chamber；Single order exhaust pipe and second order exhaust pipe and the corresponding part of the second resonant cavity, micropunch are arranged Tracheae and the corresponding part of third resonant cavity, three rank exhaust pipes and the corresponding part of the 4th resonant cavity and expansion perforation row Tracheae is equipped with to the 4th corresponding part of resonant cavity along the equally distributed multiple micropores of corresponding tube wall.

Further, be equipped on the first annular plate and third annular slab it is front and rear penetrate through flow through hole；The Fourth Ring The bend pipe for the exhaust outlet for communicating and be oriented to air-flow third housing with the 4th resonant cavity is fixed on rear side of shape plate；The bend pipe is Multiple, which part bend pipe corresponds to expansion perforated exhaust pipe setting, remaining bend pipe and expansion perforated exhaust pipe and micropunch row Tracheae front end is equipped with the expansion exhaust pipe forward extended out；The diameter of bend pipe is more than corresponding expansion perforated exhaust pipe or expansion Open the diameter of exhaust pipe.

Further, the cellular structure ceramic carrier includes the honeycomb ceramics and correspondence of multiple air flues with parallel side-by-side arrangement Dislocation type is fixed on the baffle in each air flue between two air flues of arbitrary neighborhood；Two air flue of arbitrary neighborhood is separated in honeycomb ceramics Between part be equipped with cordierite filter layer.

Further, liner is equipped between the cellular structure ceramic carrier and second shell.

Further, the first shell corresponds to catalyst carrier for purifying side equipped with the first resonant cavity and the first resonant cavity Accent towards catalyst carrier for purifying.

Further, the first shell correspond to its own air inlet to the part between catalyst carrier for purifying be along air-flow The pyramidal structure that direction cross section becomes larger.

Further, first resonant cavity is multiple and around catalyst carrier for purifying side close-packed arrays；First is common The chamber that shakes is surrounded by the inner cylinder being set in first shell and the partition board being fixed between inner cylinder and first shell；The partition board includes edge The circumferentially disposed annular partition of inner cylinder and the longitudinal baffle for being parallel to inner cylinder axis；Annular partition and longitudinal baffle are in right-angled intersection Formula is fixed together, and the accent of the first resonant cavity is set on inner cylinder and is round closed-entry structure.

The beneficial effects of the invention are as follows：The diesel engine vent gas compound noise-reducing device of the present invention, compact-sized, space utilization is closed Reason can be filtered tail gas and purify and preferably eliminate multifrequency time noise, realize tail gas clean-up and the common work of noise reduction Make, simple in structure, at low cost, service life is long, is easily installed and dismantles；Tail gas clean-up and acoustical absorptivity are high.

Description of the drawings

Fig. 1 is the structural diagram of the present invention；

Fig. 2 is exhaust silencer fragmentary isometric views；

Fig. 3 is microparticles collection device structure diagram；

Fig. 4 is microparticles collection device fragmentary isometric views.

Specific embodiment

Fig. 1 is the structural diagram of the present invention；Fig. 2 is exhaust silencer fragmentary isometric views；Fig. 3 is microparticles collection device Structure diagram；Fig. 4 is microparticles collection device fragmentary isometric views, as shown in the figure：The diesel engine vent gas recycling of the present embodiment Purification and noise reduction set composite, including catalytic oxidizing equipment, microparticles collection device and exhaust silencer；The catalytic oxidizing equipment Including the catalyst carrier for purifying 2 for being equipped with the first shell 1 of air inlet and exhaust outlet and being fixed in first shell 1；Purification Supported catalyst in catalyst carrier 2；The first shell 1 corresponds to 2 side of catalyst carrier for purifying and is equipped with the first resonant cavity 3 simultaneously And first resonant cavity 3 accent towards catalyst carrier for purifying 2；The microparticles collection device is fixed on the exhaust of first shell 1 Mouth is used to adsorbing and filtering PM particles；The exhaust silencer is fixed on the exhaust end of microparticles collection device；The micro particle catching Device includes second shell 6 and the cellular structure ceramic carrier being fixed in second shell 6；The second shell 6 is fixed on first The exhaust outlet of housing 1 is simultaneously communicated with first shell 1；The exhaust silencer includes the third housing equipped with air inlet and exhaust outlet It 10 and is fixed in third housing 10 and connects the air inlet of third housing 10 to the staged reducing exhaust pipe of exhaust outlet；Institute The inlet end diameter for stating staged reducing exhaust pipe is more than exhaust end diameter, and staged reducing exhaust pipe becomes smaller successively including caliber And single order exhaust pipe 11, the 12 and three rank exhaust pipe 13 of second order exhaust pipe of plug-in type setting；The air inlet of third housing 10 is consolidated Due to microparticles collection device；Second order exhaust pipe 12 is inserted into the exit of single order exhaust pipe 11, and three rank exhaust pipes 13 are inserted into second order row The exit of tracheae 12 makes acoustic impedance mutate using the inserting pipe-type structure combination abrupt change of cross-section, so as to fulfill cancellation is interfered, Achieve the purpose that the Middle and low frequency noise that disappears, realize that vent gas treatment and noise reduction work together, simple in structure, at low cost, service life is long, It is easily installed and dismantles, acoustical absorptivity is high, and generation back pressure is small, and core technology has universality, can be subject to restoration and reuse in similar Field；Catalytic oxidizing equipment, microparticles collection device and exhaust silencer three are linked together by flange arrangement, are easily installed And dismounting, efficient per partly working independently, co-operation can be achieved to mutually promote, and vent gas treatment and noise is made to reduce simultaneously in fact It is existing, greatly improve purification and noise reduction efficacy；Diesel engine vent gas passes through catalyst carrier for purifying by the air inlet of first shell 1 2 flow to the exhaust outlet of first shell 1, and catalyst carrier for purifying 2 is fixed on the inner wall of first shell 1, catalyst carrier for purifying 2 Side refers to the surface that catalyst carrier for purifying 2 is connect with first shell 1, and catalyst carrier for purifying 2 is corresponded in first shell 1 Side sets the first resonant cavity 3, and compact-sized, space utilization is reasonable, and catalysis oxidation converter DOC is mutually tied with resonator chamber It closes, the catalyst carrier for purifying is equipped with the multiple ducts being arranged in juxtaposition, and Ti-Si catalyst, purifying and catalyzing are fixed between duct Agent carrier is by cordierite to form reticular structure, forms intensive duct, cordierite diameter 40-100nm, and titanium silicon is fixed between duct Catalyst, i.e. Ti-Si catalyst are fixed in the carrier structure being separated between adjoining cell channels, and catalyst is made to be not easy to reveal, and are stablized It is and adaptable；Tail gas is during 2 duct of DOC catalyst carrier for purifying is flowed through, and the substances such as HC therein are by purifying and catalyzing The primary air area in 2 duct of agent carrier enters active layer, is adsorbed in cordierite (Almasilate) activity that carrier duct coating wall covers Layer surface simultaneously forms complex compound, and the product after catalysis reaction occurs under the action of Ti-Si catalyst for complex compound from cordierite (Almasilate) active layer surface desorption, finally enters PM control zones in a manner of back-diffusion by diffusion admittance；Sound wave diffuses into Enter the first resonant cavity 3, reduce acoustic energy, and then reduce low-frequency noise with the heat dissipation of accent wall friction and cavity internal resonance cancellation, And impact of the air-flow to first shell 1 can be alleviated, further reduce noise, reach can catalysis oxidation pernicious gas and Disappear the purpose of Middle and low frequency noise.

In the present embodiment, the staged reducing exhaust pipe is fixed on 10 inner wall of third housing, institute by annular slab component It states annular slab component and includes the first annular plate 14, the second annular slab 15, third ring along staged reducing exhaust pipe axial alignment Shape plate 16 and fourth annular plate 17；First annular plate 14 is set on 11 middle front part of single order exhaust pipe；Second annular slab 15 is set on second order The rear end of exhaust pipe 12 makes to form the second resonant cavity between the second annular slab 15 and first annular plate 14；Third annular slab 16 is set on The middle part of three rank exhaust pipes 13 makes to form third resonant cavity, fourth annular plate 17 between 16 and second annular slab 15 of third annular slab Make to form the 4th resonant cavity between fourth annular plate 17 and third annular slab 16 set on the middle and back of three rank exhaust pipes 13, make gas Reaction is rubbed, collided and interfered in each resonant cavity, has converted acoustic energy into thermal energy, so as to eliminate high-frequency noise, together When each annular slab provide reliable and stable mounting structure for staged reducing exhaust pipe, compact-sized, space utilization is reasonable, And impact of the air-flow to third housing 10 can be alleviated, further reduce noise.

In the present embodiment, between the rear end of the single order exhaust pipe 11 and second order exhaust pipe 12 by ring sealing plate connection simultaneously Sealing；The micropunch row of the second resonant cavity of connection and the 4th resonant cavity is fixed between second annular slab 15 and third annular slab 16 Tracheae 18；Connection third resonant cavity is fixed between third annular slab 16 and fourth annular plate 17 and fourth annular plate 17 arrives third The expansion perforated exhaust pipe 19 of chamber between the exhaust outlet of housing 10；Single order exhaust pipe 11 and second order exhaust pipe 12 and second are common The corresponding part of the chamber that shakes, micropunch exhaust pipe 18 and the corresponding part of third resonant cavity, three rank exhaust pipes 13 and the 4th are common The corresponding part of the chamber that shakes and expansion perforated exhaust pipe 19 are equipped with to the 4th corresponding part of resonant cavity along corresponding tube wall Equally distributed multiple micropores 20, make staged reducing exhaust pipe and the second resonant cavity, third resonant cavity and the 4th resonant cavity it Between and each chamber between by micropore 20 or the effective intercommunication of pipeline, friction heat dissipation, consumption when gas expansion passes through hole wall Acoustic energy.

In the present embodiment, front and rear perforation is equipped on the first annular plate 14 and third annular slab 16 flows through hole 21； The rear side of the fourth annular plate 17 is fixed with the exhaust outlet that communicates and be oriented to air-flow third housing 10 with the 4th resonant cavity Bend pipe 22；To be multiple, which part bend pipe 22 corresponds to expansion perforated exhaust pipe 19 and sets the bend pipe 22, remaining bend pipe 22 and Each expansion perforated exhaust pipe 19 and 18 front end of micropunch exhaust pipe are equipped with the expansion exhaust pipe 23 forward extended out；Bend pipe 22 Diameter is more than corresponding expansion perforated exhaust pipe 19 or expands the diameter of exhaust pipe 23, by expansion perforated exhaust pipe 19 and expands The air-flow for opening exhaust pipe 23 into bend pipe 22 causes acoustic impedance to be mutated by the abrupt change of cross-section, utilizes the principle for interfering cancellation, eliminates Partial noise, the air-flow of 16 both sides of first annular plate 14 and third annular slab can be carried out by flowing through hole 21 to a certain extent Circulation improves the balance of system, friction heat dissipation, sound energy consumption, the exhaust ports design of bend pipe 22 when gas expansion passes through hole wall Into 60 ° of convective structures, the partial noise of rear end remnants is made to generate interaction using convection mechanism, by the collision of molecule and dry Relating to cancellation reduces multifrequency time noise, finally using the big performance of staged reducing exhaust pipe air-flow, the gas for discharging bend pipe 22 The exhaust outlet discharge of third housing 10 is flowed under main exhaust airflow function, ensure that gas is not blocked, realize preferably Circulation.

In the present embodiment, the cellular structure ceramic carrier includes the honeycomb ceramics 7 of multiple air flues with parallel side-by-side arrangement Dislocation type is fixed on the baffle 8 in each air flue between two air flues of corresponding arbitrary neighborhood；Arbitrary two adjacent gas in honeycomb ceramics 7 Partition board between road is cordierite filter layer, the circulation of corresponding air flue interior air-flow can be blocked by baffle 8, therefore enter honeycomb ceramics Cordierite filter layer of the air-flow under the barrier effect of baffle 8 across adjacent two air flue in 7 enters adjacent air flue, realizes Whole air-flows are effectively filtered, purification efficiency is high, and multiple baffles 8 can be set in air flue, makes air-flow repeatedly by adjacent Wall surface between air flue is filtered, using diffusion, interception and inertial collision mechanism, by particulate deposits in cellular structure ceramic carrier Within, when particle is stacked into port certain position, since the position has been right up to the fuel value point of particle, in addition this device should For large-scale diesel engine, delivery temperature when flowing through microparticles collection device is more than particle ignition temperature, so can in port position It to be directly realized by the burning of particle, and then realizes the regeneration of microparticles collection device, ensures the normal work shape of microparticles collection device State.

In the present embodiment, liner 9 is equipped between the cellular structure ceramic carrier and second shell 6, is not only improved cellular The stability of ceramic monolith mounting structure, and vibration and punching between cellular structure ceramic carrier and second shell 6 can be buffered It hits, noise can be reduced and reduces equipment failure rate.

In the present embodiment, the first shell 1 corresponds to its own air inlet and is to the part between catalyst carrier for purifying 2 The pyramidal structure become larger along airflow direction cross section, forms unexpected expansion chambers, acoustic impedance is caused to be mutated by the abrupt change of cross-section, Using the principle for interfering cancellation, part low frequency induction noise is eliminated.

In the present embodiment, first resonant cavity 3 is multiple and around 2 side close-packed arrays of catalyst carrier for purifying； First resonant cavity 3 is surrounded by the inner cylinder 4 being set in first shell 1 and the partition board 5 being fixed between inner cylinder 4 and first shell 1；Institute Partition board 5 is stated to include along the circumferentially disposed annular partition of inner cylinder 4 and the longitudinal baffle for being parallel to 4 axis of inner cylinder；Annular partition and vertical It is fixed together to partition board in right-angled intersection formula, the accent of the first resonant cavity 3 is set on inner cylinder 4 and is round closed-entry knot Structure, the first resonant cavity 3 are compact arranged multiple small cavity configurations, can preferably realize resonance cancellation, further reduce low frequency and make an uproar Gap between first shell 1 and inner cylinder 4 is separated by sound, the first resonant cavity 3 by using partition board 5, and cleaning catalyst carries Body 2 is fixed on 4 inner wall of inner cylinder；Round closed-entry structure refers to that the accent of the first resonant cavity 3 is less than the section of the first resonant cavity 3, The first resonant cavity 3 is made to form the small and internal broad structure of accent；Partition board 5 can also be such as lower structure：It is circumferentially set including inner cylinder 4 The helical baffle put and the longitudinal baffle for being parallel to 4 axis of inner cylinder；Helical baffle is integrally formed with inner cylinder 4；Longitudinal baffle and One housing 1 is integrally formed, and longitudinal baffle is equipped with the multiple card slots screwed in for helical baffle, the distance between card slot and spiral every The screw pitch of plate is equal, and overall construction intensity is high, easy to process, and when assembling screws in inner cylinder 4 in first shell 1, easy to operate, knot Structure consolidates, and the gap between inner cylinder 4 and first shell 1 is separated into the first resonant cavity 3 using helical baffle and longitudinal baffle.

In the present embodiment, the duct wall surface coating cordierite of the catalyst carrier for purifying 2 forms active layer, makes cordierite It is uniformly distributed, by diffusion mechanism, reaches better catalytic oxidation effect, cause air flow through the hole in catalyst carrier for purifying 2 Achieve the purpose that carry out catalysis oxidation conversion to exhaust gas during road.

Finally illustrate, the above embodiments are merely illustrative of the technical solutions of the present invention and it is unrestricted, although with reference to compared with The present invention is described in detail in good embodiment, it will be understood by those of ordinary skill in the art that, it can be to the skill of the present invention Art scheme is modified or replaced equivalently, and without departing from the objective and range of technical solution of the present invention, should all be covered at this In the right of invention.

Claims

1. a kind of diesel engine vent gas compound noise-reducing device, it is characterised in that：Including catalytic oxidizing equipment, it is fixed on catalysis oxidation dress The exhaust end put is used to adsorbing and filtering the microparticles collection device of PM particles and is fixed on the exhaust end row of microparticles collection device Gas silencer；The catalytic oxidizing equipment includes the first shell equipped with air inlet and exhaust outlet and is fixed in first shell Catalyst carrier for purifying；Supported catalyst on catalyst carrier for purifying；The microparticles collection device is including second shell and admittedly Due to the cellular structure ceramic carrier in second shell；The second shell is fixed on the exhaust outlet of first shell and and first shell It communicates；The exhaust silencer includes being equipped with the third housing of air inlet and exhaust outlet and is fixed in third housing and connects The air inlet of third housing to exhaust outlet staged reducing exhaust pipe；The staged reducing exhaust pipe becomes successively including caliber Single order exhaust pipe, second order exhaust pipe and the three rank exhaust pipes of small and plug-in type setting；The air inlet of third housing is fixed on micro- Grain capturing device；The cellular structure ceramic carrier includes the honeycomb ceramics of multiple air flues with parallel side-by-side arrangement and corresponds to arbitrary Dislocation type is fixed on the baffle in each air flue between two neighboring air flue；It is separated in honeycomb ceramics between two air flue of arbitrary neighborhood Part be equipped with cordierite filter layer；The first shell corresponds to catalyst carrier for purifying side equipped with the first resonant cavity and the The accent of one resonant cavity is towards catalyst carrier for purifying；First resonant cavity is multiple and around catalyst carrier for purifying side Face close-packed arrays；First resonant cavity is enclosed by the inner cylinder being set in first shell and the partition board being fixed between inner cylinder and first shell Into；The partition board is included along the circumferentially disposed annular partition of inner cylinder and the longitudinal baffle for being parallel to inner cylinder axis；Annular partition and Longitudinal baffle is fixed together in right-angled intersection formula, and the accent of the first resonant cavity is set on inner cylinder and is round closed-entry knot Structure.

2. diesel engine vent gas compound noise-reducing device according to claim 1, it is characterised in that：The staged reducing exhaust Pipe is fixed on third inner walls by annular slab component, and the annular slab component includes axially arranging along staged reducing exhaust pipe First annular plate, the second annular slab, third annular slab and the fourth annular plate of row；Before first annular plate is set in single order exhaust pipe Portion；The rear end that second annular slab is set on second order exhaust pipe makes to form the second resonant cavity between the second annular slab and first annular plate； Third annular slab, which is set in the middle part of three rank exhaust pipes, to be made to form third resonant cavity between third annular slab and the second annular slab, and the 4th The middle and back that annular slab is set on three rank exhaust pipes makes to form the 4th resonant cavity between fourth annular plate and third annular slab.

3. diesel engine vent gas compound noise-reducing device according to claim 2, it is characterised in that：After the single order exhaust pipe It connects and seals by ring sealing plate between end and second order exhaust pipe；Connection is fixed between second annular slab and third annular slab The micropunch exhaust pipe of second resonant cavity and the 4th resonant cavity；Connection third is fixed between third annular slab and fourth annular plate Resonant cavity and fourth annular plate are to the expansion perforated exhaust pipe of the chamber between the exhaust outlet of third housing；Single order exhaust pipe and two The rank exhaust pipe and corresponding part of the second resonant cavity, the micropunch exhaust pipe and corresponding part of third resonant cavity, three ranks row Tracheae part corresponding with the 4th resonant cavity and expansion perforated exhaust pipe are equipped with the 4th corresponding part of resonant cavity Along the equally distributed multiple micropores of corresponding tube wall.

4. diesel engine vent gas compound noise-reducing device according to claim 3, it is characterised in that：The first annular plate and Front and rear perforation is equipped on three annular slabs flows through hole；It is fixed on rear side of the fourth annular plate and is communicated simultaneously with the 4th resonant cavity Air-flow is oriented to the bend pipe of the exhaust outlet of third housing；The bend pipe is multiple, and which part bend pipe corresponds to expansion perforation exhaust Pipe is set, remaining bend pipe and expansion perforated exhaust pipe and micropunch exhaust pipe front end are equipped with the expansion exhaust forward extended out Pipe；The diameter of bend pipe is more than corresponding expansion perforated exhaust pipe or expands the diameter of exhaust pipe.

5. diesel engine vent gas compound noise-reducing device according to claim 1, it is characterised in that：The cellular structure ceramic carrier Liner is equipped between second shell.

6. diesel engine vent gas compound noise-reducing device according to claim 1, it is characterised in that：The first shell corresponds to it Itself air inlet is the pyramidal structure become larger along airflow direction cross section to the part between catalyst carrier for purifying.