CN114673576B

CN114673576B - High-power diesel engine exhaust purifying silencing integrated device

Info

Publication number: CN114673576B
Application number: CN202210476680.9A
Authority: CN
Inventors: 肖友洪; 王伟明; 邵延忠; 赵辉; 党知非; 李航宸
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2022-04-30
Filing date: 2022-04-30
Publication date: 2023-10-17
Anticipated expiration: 2042-04-30
Also published as: CN114673576A

Abstract

The invention provides an exhaust purification and noise elimination integrated device of a high-power diesel engine, which comprises a closed device cavity; a catalyst module is arranged in the device cavity; the catalyst module divides the device cavity into a catalyst front bin and a catalyst rear bin; the device also comprises a tail gas inlet pipe; the tail gas inlet pipe extends into the front catalyst bin; a first isolation structure is arranged in the front catalyst bin, and the front catalyst bin is divided into a first bin and a second bin by the first isolation structure; the tail gas inlet pipe is arranged in the first bin, and the end part of the tail gas inlet pipe is arranged on the first isolation structure; a first through hole is formed in the pipe wall of the tail gas inlet pipe; a movable isolation structure is arranged in the first bin; the movable isolation structure can move in a direction approaching-away from the exhaust gas inlet pipe. The invention can be widely applied to the field of silencing and purifying of high-power diesel engines.

Description

High-power diesel engine exhaust purifying silencing integrated device

Technical Field

The invention relates to the technical field of high-power diesel engines, in particular to the technical field of exhaust purification and noise control of marine diesel engines and railway locomotive diesel engines.

Background

Diesel engines are widely used power equipment, and the adverse effect of diesel engines on the environment is also receiving more attention today when people pay more attention to environmental protection. Nitrogen Oxides (NO)x) is one of the main pollutants in the exhaust gas of diesel engine, including NO, NO ₂ 、N ₂ O、N ₂ O ₂ 、N ₂ O ₃ And N ₂ O ₅ Etc. Wherein NO is about 90-95%. NO entering the atmosphere can generate NO through slow oxidation ₂ ，NO ₂ Is easy to combine with hemoglobin in blood, and causes hypoxia, nerve center disorder and NO ₂ Has strong irritation to mucous membrane, and can cause insomnia, cough, respiratory urgency and mucous membrane corrosion, and easily die due to pulmonary edema. In addition, NOx and HC easily generate photochemical smog under the action of ultraviolet rays in sunlight under proper conditions, and serious harm is generated.

The installation of after-treatment devices in the exhaust system is one of the effective measures for diesel NOx emission control, such as the widely used Selective Catalytic Reduction (SCR) technology. The SCR device is arranged in an exhaust system of the diesel engine, and urea solution is sprayed into the upstream of the SCR device when the diesel engine works. Due to the higher temperature of the waste gas, the urea solution is decomposed into NH after atomization and evaporation ₃ And CO ₂ . Generated NH ₃ Enters a catalyst carrier, and converts NOx into harmless nitrogen and water under the action of the catalyst, so that the content of NOx discharged into the atmosphere is reduced.

Noise generated when a diesel engine is operated is also an environmental pollution source, in which a large amount of noise is generated due to pressure variation and vibration during the exhaust of the diesel engine. The noise generated in the operating state of high-power diesel engines such as marine diesel engines and railway locomotive diesel engines is particularly serious. The operating power range and the rotating speed range of the diesel engine are wide, and exhaust noise is usually mainly at medium and low frequencies (low frequency noise <500Hz and medium frequency noise 500 Hz-2000 Hz). For high-power diesel engines, exhaust gas turbochargers are commonly installed to improve the power performance and the economic performance, and the high-speed operation of the turbochargers generates strong aerodynamic noise, so that the high-frequency noise (> 2000 Hz) component is also strong.

In order to solve the adverse effects of the pollutants and noise on the environment, the prior art has respectively added an SCR device and a noise reduction device in a diesel engine emission system. The prior art scheme has the defects that the SCR device and the noise reduction device are respectively arranged, so that the system is huge in volume, and great operation cost is generated for practical application. For this reason, attempts have been made to integrate the two devices together to form a sound-deadening and purifying device to reduce the volume. However, the existing silencing and purifying device has the following main problems: the noise elimination purification device can only eliminate noise with specific frequency, and exhaust of different working states of the diesel engine can be accompanied by noise with different frequencies, so that the existing noise elimination purification device has low adaptability, so that the noise elimination effect of the existing noise elimination purification device does not meet the requirements of practical application.

Disclosure of Invention

The invention provides an exhaust purification and silencing integrated device of a high-power diesel engine, which aims to solve the problem that the existing silencing and silencing device of the diesel engine exhaust does not meet the actual application requirements.

The technical scheme of the invention is as follows:

the high-power diesel engine exhaust purification and silencing integrated device comprises a closed device cavity; a catalyst module is arranged in the device cavity; the catalyst module is tightly connected with the inner wall of the device cavity and divides the device cavity into a catalyst front bin and a catalyst rear bin; the device also comprises a tail gas inlet pipe; the tail gas inlet pipe extends into the catalyst front bin; a first isolation structure is arranged in the front catalyst bin and divides the front catalyst bin into a first bin and a second bin; the tail gas inlet pipe is arranged in the first bin, the end part of the tail gas inlet pipe is arranged on the first isolation structure, and the interior of the tail gas inlet pipe is communicated with the second bin through the end part of the tail gas inlet pipe; a first through hole is formed in the pipe wall of the tail gas inlet pipe; a movable isolation structure is arranged in the first bin; the movable isolation structure may be movable in a direction toward-away from the exhaust gas inlet pipe.

Optionally, the portion of the exhaust gas inlet pipe adjacent to the first isolation structure is an exhaust gas inlet pipe tail section; the radial dimension of the cross section of the tail gas inlet pipe perpendicular to the axis of the tail gas inlet pipe is gradually increased along the flow direction of the tail gas.

Optionally, a urea nozzle is provided in the exhaust gas inlet pipe.

Optionally, a first driving mechanism for driving the movable isolation structure to perform the movement is arranged on the device cavity.

Optionally, a first spherical cap shell is arranged on one side, facing the direction of the catalyst module, of the first isolation structure; the first spherical cap shell protrudes towards the direction of the catalyst module and covers the end part of the exhaust gas inlet pipe; the first spherical cap shell is provided with a first air hole penetrating through the first spherical cap shell.

Optionally, a second spherical cap shell accommodating the first spherical cap shell is arranged on one side of the first isolation structure facing the catalyst module direction; an air gap is arranged between the first spherical crown shell and the second spherical crown shell; a second air hole penetrating through the second spherical cap shell is formed in the second spherical cap shell; the first air holes and the second air holes are at least partially staggered.

Optionally, a second isolation structure is fixedly arranged between the catalyst module and the first isolation structure; a cylindrical straight pipe is arranged on the second isolation structure; the cylindrical straight pipe penetrates through the second isolation structure, and the axis of the cylindrical straight pipe is arranged along the connecting line direction of the first isolation structure and the catalyst module; the end part of the cylindrical straight pipe, which faces the first isolation structure, is an open end part, and the end part of the cylindrical straight pipe, which faces the catalyst module, is a closed end part; the cylindrical straight pipe is provided with a second through hole on a side wall of a portion between the second isolation structure and the catalyst module.

Optionally, the number of the cylindrical straight pipes is greater than 1, and the axes of the cylindrical straight pipes are parallel.

Optionally, the number of second through holes is greater than 1; the diameter of the second through hole ranges from 8 mm to 15 mm; the perforation rate of the second through hole is more than 45%.

Optionally, the cylindrical straight tube is provided with a sliding isolation structure slidable along an axial direction of the cylindrical straight tube on an outer wall of a portion between the first isolation structure and the second isolation structure; the sliding isolation structure is in sliding fit with the cylindrical straight pipe; the sliding isolation structure is in sliding fit with the inner wall of the device cavity.

Optionally, a second driving mechanism is provided for driving the sliding isolation structure to perform the sliding.

Optionally, a perforated plate is provided between the closed end of the cylindrical straight tube and the catalyst module; the perforated plate is provided with a third through hole; the perforated plate separates the closed end of the cylindrical straight tube from the catalyst module.

Optionally, the number of third through holes is greater than 1; the diameter range of the third through hole is 8-15 mm; the perforation rate of the third through hole is more than 50%.

Optionally, a tail pipe is arranged in the catalyst rear bin; the tail pipe is provided with a tail pipe first end and a tail pipe second end for gas to enter and exit; the first end of the tail pipe is covered and communicated with a gas outlet on the catalyst module, and the second end of the tail pipe is communicated with the outside of the device cavity; the radial dimension of the tail pipe decreases stepwise from the tail pipe first end to the tail pipe second end.

Optionally, a fourth through hole is provided on a side wall of the tail pipe.

Optionally, the number of fourth through holes is greater than 1; the diameter range of the fourth through hole is 8-15 mm; the perforation rate of the fourth through hole is more than 50%.

Optionally, a sound absorbing material is provided between the tailpipe and the device cavity.

The invention has the following technical effects:

the invention relates to an exhaust purification and noise elimination integrated device of a high-power diesel engine, wherein a resonance cavity is formed by a tail gas inlet pipe with a first through hole on the pipe wall and a first bin, and a movable isolation structure is arranged in the resonance cavity. As the movable isolation structure approaches or departs from the exhaust gas inlet pipe, the volume of the resonant cavity is changed. According to the Helmholtz sound absorption principle, the volume of the resonant cavity is reduced, the working frequency is increased, and the higher-frequency noise can be eliminated; conversely, an increase in the volume of the resonant cavity may eliminate noise at lower frequencies. Therefore, the technical scheme of the invention can correspondingly eliminate the noise of the current frequency by adjusting the volume of the resonant cavity along with the change of the working state of the diesel engine, thereby realizing the purpose of the invention.

Further effects of the above alternatives will be described below in connection with the embodiments.

Drawings

Fig. 1 is a perspective cross-sectional view of one embodiment of the present invention.

FIG. 2 is a perspective view of a first plenum portion structure of the embodiment shown in FIG. 1.

Fig. 3 is a perspective view of the first spherical cap shell of the embodiment of fig. 1.

Fig. 4 is a perspective view of the first spherical cap housing and the second spherical cap housing of the embodiment shown in fig. 1 after assembly.

Fig. 5 is a perspective view of the embodiment of fig. 1 of a straight tube and associated components.

Fig. 6 is a perspective view of the tail pipe of the embodiment of fig. 1.

Fig. 7 is a schematic diagram of the sound damping of a cylindrical straight pipe.

The identification in the figures is as follows:

101. a tail gas inlet pipe; 102. a urea nozzle; 103. a first partition plate; 104. a second partition plate; 105. a perforated plate; 106. a third through hole; 107. a catalyst module; 108. a catalyst rear bin; 109. an exhaust tail pipe; 110. an extension tube; 111. a device cavity; 112. a second chamber; 113. a first chamber;

201. a device cavity wall; 202. a guide rod; 203. a stepping motor; 204. a movable isolation plate; 205. a second spherical cap shell; 2051. a second spherical cap housing wall; 2052. a second air hole; 206. a first through hole; 207. tail gas enters the tail section of the pipe;

301. a first air hole; 302. a first spherical cap housing wall;

501. an open end; 502. a cylindrical straight tube; 503. sliding the isolation plate; 504. a guide rod; 505. a stepping motor; 506. a second through hole; 507. closing the end;

601. a tailpipe first end; 602. a fourth through hole; 603. and a tailpipe second end.

Detailed Description

The technical scheme of the present invention will be described in detail with reference to the embodiments shown in the drawings.

Fig. 1 shows a main structure of an embodiment of the exhaust purifying and silencing integrated device for a high-power diesel engine of the present invention. The high-power diesel engine exhaust purifying and silencing integrated device comprises a device cavity 111. The device chamber 111 is a rectangular parallelepiped chamber, and the gas exhausted from the diesel engine enters and exits along the long axis direction of the device chamber 111, that is, the flow direction of the gas exhausted from the diesel engine flows from left to right in fig. 1. The device cavity 111 is rectangular in cross-section perpendicular to the long axis. The device chamber 111 is a closed chamber, except for the exhaust gas inlet pipe 101 and the extension pipe 110, that is, except for the inlet and outlet of the gas, the inside and outside of the device chamber 111 are isolated.

As can be seen in fig. 1, a catalyst module 107 is disposed within the device cavity 111. The catalyst module 107 is a rectangular parallelepiped body composed of a honeycomb-shaped catalyst carrier, and four faces of the rectangular parallelepiped body are closely connected to four inner walls of the device cavity 111, respectively, so that the catalyst module 107 partitions the internal space of the device cavity 111 into a catalyst front bin (the catalyst module 107 in fig. 1) and a catalyst rear bin 108. In the present invention, the term "partition" or "isolation" means that a partition structure or isolation structure divides one space into two spaces, which are in a non-conductive state except for a communication passage provided therebetween, unless otherwise specified.

The exhaust gas inlet pipe 101 extends into the catalyst front chamber along the left side of the long axis direction of the device chamber 111. The left end of the tail gas inlet pipe 101 is communicated with the diesel engine, and the tail gas inlet pipe 101 is used for discharging the waste gas generated by the operation of the diesel engine. A urea nozzle 102 is provided in the exhaust gas inlet pipe 101.

A first partition plate 103 is provided in the catalyst front, and the first partition plate 103 partitions the catalyst front into a first chamber 113 and a second chamber 112. That is, the space between the left side of the first partition plate 103 and the inner wall of the left end of the device cavity 111 in fig. 1 is the first chamber 113; the space between the right side of the first partition plate 103 and the catalyst module 107 is the second plenum 112.

A second partition plate 104 is provided in the second chamber 112, and the second partition plate 104 further partitions the second chamber 112 into two spaces, that is, a space between the second partition plate 104 to the first partition plate 103 and a space between the second partition plate 104 to the catalyst module 107 as a partition structure. A perforated plate 105 is further provided in the space between the second partition plate 104 and the catalyst module 107. The perforated plate 105 divides the space between the second separator plate 104 and the catalyst module 107 into two parts, i.e., a space part between the perforated plate 105 and the second separator plate 104 and a space part between the perforated plate 105 and the catalyst module 107. The perforated plate 105 is uniformly provided with a plurality of third through holes 106, the diameter range of the third through holes 106 is 8-15 mm, and the perforation rate of the third through holes is more than 50% (perforation rate is the ratio of the total area of the holes to the total area of the perforated plate 105). In the present embodiment, the plate-like perforated plate 105 is parallel to the left end face of the catalyst module 107 and is 5 cm apart from the same.

A tail pipe 109 is provided in the catalyst rear chamber 108. Referring to fig. 6, a first end 601 of the tail pipe 109 covers and communicates with the gas outlet of the catalyst module 107, and a second end 603 of the tail pipe 109 communicates with the outside of the device cavity 111 through an extension pipe 110. A sound absorbing material is provided between the tail pipe 109 and the inner wall of the device cavity 111. The sound absorbing material can be fibrous sound absorbing material, granular sound absorbing material or foam sound absorbing material.

The specific structure of each component of the present embodiment will be described in detail below with reference to other drawings.

FIG. 2 shows a specific structure of a relevant portion of the first plenum 113 in FIG. 1. As shown in fig. 2, the device cavity wall 201 and the first partition plate 103 constitute a first plenum 113. The exhaust gas inlet pipe 101 is disposed in the first plenum 113, specifically a portion of the exhaust gas inlet pipe 101, the exhaust gas inlet pipe tail section 207. The tail gas inlet pipe end section 207 is part of the tail gas inlet pipe 101 end section of fig. 1. The tail gas inlet pipe tail section 207 takes the shape of an expanded truncated cone, i.e. the radial dimension of the cross section of the tail gas inlet pipe tail section 207 perpendicular to the axis of the tail gas inlet pipe 101 increases gradually in the direction of the flow of the tail gas (left to right direction in fig. 1). The end of the exhaust gas inlet pipe 101, i.e. the end of the exhaust gas inlet pipe tail section 207, is arranged on the first separator plate 103. The end of the tail gas inlet tube tail section 207 is an open end through which the interior of the tail gas inlet tube 101 communicates with the second plenum 112.

A plurality of first through holes 206 are provided in the wall of the tail gas inlet pipe tail section 207. Two movable partition plates 204 are provided in the first chamber 113. The movable isolation plate 204 is connected with the guide rod 202 of the first driving mechanism. The first drive mechanism includes a stepper motor 203 disposed on the device cavity wall 201 and a movable guide bar 202 coupled to the stepper motor 203. Driven by the stepper motor 203, the guide rod 202 performs telescopic movement, so as to drive the movable isolation plate 204 to move, and the movable isolation plate is close to the tail gas inlet pipe tail section 207 or far from the tail gas inlet pipe tail section 207.

On the side of the first partition plate 103 facing in the direction of the catalyst module 107, i.e. on the side of the first partition plate 103 facing the second chamber 112, there is provided a first spherical cap housing and a second spherical cap housing 205 which are snapped onto said ends of the tail section 207 of the exhaust gas inlet pipe (see fig. 3 and 4). Both the first spherical cap housing and the second spherical cap housing 205 are convex toward the catalyst module 107.

Fig. 3 shows the structure of the first spherical cap housing. The first spherical cap housing is a housing in the shape of a spherical cap, the bottom (i.e., circular planar portion) of which snaps onto the first separator plate 103 and covers the end of the tail gas inlet pipe tail section 207. As can be seen from fig. 3, a number of first air holes 301 are provided in the first spherical cap housing through a first spherical cap housing wall 302.

Fig. 4 shows the assembly relationship of the first crown shell and the second crown shell 205 of fig. 1. The second spherical cap housing 205 is sized larger than the first spherical cap housing, and the second spherical cap housing 205 is snapped onto the first spherical cap housing such that there is sufficient clearance space between the first spherical cap housing and the second spherical cap housing 205 for the passage of gas. A plurality of second air holes 2052 are provided in the second spherical cap housing wall 2051. The first air holes 301 are at least partially staggered with the second air holes 2052. The partially staggered arrangement described herein means that in the assembled state shown in fig. 4, a partial area of the first air holes 301 is opposite the second spherical cap housing wall 2051, and a partial area of the second air holes 2052 is opposite the first spherical cap housing wall 302.

FIG. 5 shows a specific structure of the second partition 104 and the components attached thereto in the second plenum 112. Five cylindrical straight pipes 502 are provided through the second partition plate 104. Referring to fig. 1, the axes of these straight cylindrical pipes are parallel to each other and are disposed in the direction from the first separator plate 103 to the catalyst module 107. The end of the cylindrical straight pipe 502 facing the first partition plate 103 is an open end 501, and the other end of the cylindrical straight pipe 502 is disposed toward the catalyst module 107 and is a closed end 507. A plurality of second through holes 506 are provided on the side wall of the portion of the tubular straight tube 502 located between the second partition 104 and the perforated plate 105. The diameter of the second through hole 506 ranges from 8-15 mm. The second through-hole 506 has a perforation ratio of greater than 45% (perforation ratio, i.e., the ratio of the total area of holes to the total area of the side walls of the portion of the tubular straight tube 502 located between the second separator plate 104 and the perforated plate 105).

A sliding spacer 503 is provided between the second spacer 104 and the first spacer 103, and is fitted over the cylindrical straight pipe 502. The sliding isolation plate 503 is a plate-shaped body, and hollow structures are arranged on the plate-shaped body corresponding to the outer diameter and the position of the cylindrical straight pipe 502, wherein the hollow structures are used for relatively moving the cylindrical straight pipe 502, or the sliding isolation plate 503 can move along the axial direction of the cylindrical straight pipe 502. The sliding partition plate 503 further partitions the space between the first partition plate 103 and the second partition plate 104 into two spaces. The sliding separation plate 503 is in sliding fit with the cylindrical straight pipe 502; the sliding spacer 503 is a sliding fit with the inner wall of the device cavity 111.

Two stepper motors 505 are symmetrically disposed on the second separator 104. The stepper motor 505 is also provided with a guide bar 504, and the stepper motor 505 can drive the guide bar 504 to move along the long axis direction of the device cavity 111. The sliding isolation plate 503 is fixedly connected with the guide rod 504, so that the guide rod 504 can drive the sliding isolation plate 503 to move along the cylindrical straight pipe 502.

Fig. 6 shows a specific structure of the tail pipe 109. The radial dimension of the tailpipe 109 decreases progressively from the tailpipe first end 601 to the tailpipe second end 603. A plurality of fourth through holes 602 are provided in a side wall of the tail pipe 109. The diameter of the fourth through hole 602 ranges from 8 to 15 mm, and the perforation rate of the fourth through hole 602 is greater than 50% (perforation rate, i.e., the ratio of the total area of the holes to the total area of the side wall of the tail pipe 109).

The working process of the high-power diesel engine exhaust purification and silencing integrated device is described below with reference to the accompanying drawings so as to further describe the technical scheme of the invention.

The gas exhausted from the diesel engine enters the high-power diesel engine exhaust purifying and silencing integrated device through the exhaust gas inlet pipe 101, and specifically, the exhaust gas exhausted from the diesel engine enters the device cavity 111. A urea nozzle 102 is provided in the exhaust gas inlet pipe 101. The urea solution sprayed by the urea nozzle 102 is atomized and evaporated under the high temperature effect of the exhaust gas of the diesel engine, and is mixed with the exhaust gas of the diesel engine to form a mixed gas flow.

When the mixed air flow enters the tail gas inlet pipe tail section 207, the first through hole 206 and the first bin 113 form a Helmholtz sound absorption structure, and the first bin 113 serves as a resonant cavity of the Helmholtz sound absorption structure, so that generated low-frequency noise (such as fundamental frequency and harmonic noise) can be eliminated. The problem of helmholtz acoustic absorption is that only fixed frequency band's noise can be handled, and when diesel engine operating condition changes, the frequency of diesel engine exhaust noise changes, can surpass helmholtz acoustic absorption's the noise range of handling. While in the solution of the invention, a movable partition 204 is provided in the first compartment. The movable partition 204 further separates the space of the first plenum 113, wherein the space containing the exhaust gas entering the tube tail section 207 acts as a resonant cavity for the helmholtz acoustic structure. The volume of the resonant cavity changes as the movable isolation plate 204 is able to move toward or away from the tail gas inlet pipe end section 207. According to the Helmholtz resonance silencing principle, the resonance frequency can be changed by changing the volume of the resonant cavity, so that noise with different frequencies can be eliminated. For example, when the rotational speed of the diesel engine increases, the fundamental frequency and harmonic frequency in exhaust noise increase, and at this time, the stepping motor 203 is controlled to operate, so that the movable isolation plate 204 moves, the volume of the resonant cavity is reduced, and the resonant frequency increases, so that noise of a higher frequency can be eliminated. The device cavity of the high-power diesel engine exhaust purification and noise elimination integrated device is cuboid, so that the movable isolation plate 204 with simple shape and structure can change the volume of the resonant cavity. In addition, the tail gas entering pipe tail section 207 is in an expanded shape, so that vortex backflow phenomenon formed on two sides of the outlet jet flow by straight pipe air flow with uniform cross section is avoided when the mixed air flow flows out of the tail gas entering pipe tail section 207, and pressure loss when the mixed air flow flows out of the tail gas entering pipe tail section 207 is reduced.

The mixed gas stream exits the end of the tail gas inlet pipe tail section 207 and then flows through the first and second spherical cap shells 205 in sequence. Since the first air holes 301 are provided in the first spherical cap housing and the second air holes 2052 are provided in the second spherical cap housing 205, the mixed air flow can pass through the first spherical cap housing and the second spherical cap housing 205. However, since the first air holes 301 and the second air holes 2052 are at least partially staggered, at least a portion of the mixed air flow is blocked by the second spherical cap housing wall 2051 after passing through the first spherical cap housing, and a disturbance effect is exerted on the flow field of the mixed air flow. The disturbance action slows down the flow speed of the mixed gas flow on the one hand, and the disturbed flow field also promotes the urea spray in the mixed gas flow to be more fully mixed with the exhaust gas of the diesel engine, so that the decomposed ammonia gas is more uniformly distributed in the gas. The arrangement of the first spherical cap housing and the second spherical cap housing 205 realizes space-time expansion for the decomposition reaction occurring in the mixed fluid in a limited space, so that the decomposition reaction can be more fully performed. Therefore, by adopting the technical scheme of the invention, the high-power diesel engine exhaust purification and noise elimination integrated device has the advantages of compact structure and small volume. In addition, the first air holes 301 and the second air holes 2052 are at least partially staggered, and the sound waves are reflected thereby, so that the resistive silencing effect is also achieved.

The mixed air flows in the direction of the cylindrical straight pipe 502 after being discharged from the second spherical cap housing 205. The straight tube 502 has an intermediate frequency sound damping function as known in the art of insert tubes. According to the sound damping principle of the cylindrical straight pipe shown in fig. 7, the resonance frequency formula generated at the cylindrical straight pipe 502 is as follows:

wherein f is the sound wave frequency in Hz; c is the sound velocity in m/s; l (L) ₃ The unit of the depth of the insertion cavity for the insertion tube is m; n represents a resonance frequency point.

The movement of the sliding spacer 503 represents l in the above formula ₃ A change occurs. Therefore, the sliding of the sliding partition plate 503 can change the resonance frequency at the tubular straight pipe 502, that is, the frequency at which noise is eliminated can be changed. According to the above formula, when the sliding partition plate 503 moves leftward, l ₃ Decreasing, the resonant frequency increases, i.e. noise at higher frequencies is eliminated; conversely, when the sliding partition plate 503 moves rightward, l ₃ Increasing the resonance frequency decreases, i.e. noise at lower frequencies is eliminated. Therefore, due to the arrangement of the sliding partition plate 503, intermediate frequency noise of a wider frequency range can be handled at the cylindrical straight pipe 502.

The mixed gas stream exits the second through hole 506 of the straight tube 502. The flow direction of the mixed fluid passing through the second through holes 506 is changed, and the jet flow formed through the second through holes 506 with smaller aperture enters the space between the perforated plate 105 and the second partition plate 104 to be further mixed, so that urea in the mixed fluid is more fully decomposed into ammonia before the catalyst module 107, and the ammonia is more uniformly distributed. The mixed fluid discharged from the second through holes 506 passes through the third through holes 106 on the perforated plate 105 to reach the catalyst module 107. The perforated plate 105 has a rectifying effect so that the mixed fluid can continue to flow in a smooth, parallel direction to the direction of the gas flow channels in the catalyst module. The perforated plate 105 also has some mid-high frequency muffling effect.

A honeycomb catalyst carrier is disposed in the catalyst module 107 through which the mixed gas stream passes. The carrier is coated with a selective catalytic reduction catalyst, which is formed by NH ₃ Is used for catalytic purification of NOx. When the sound waves enter and exit the honeycomb carrier pore channels, the sound waves rub against the inner pore channel wall surfaces of the carrier to generate energy loss, which is equivalent to resistive silencing, so that the catalyst module 107 also has a certain middle-high frequency silencing effect.

The gas discharged from the catalyst module 107 enters the tail pipe 109. The tail pipe 109 transitions from a rectangular cross section at the first end 601 of the tail pipe to a circular cross section at the second end 603 of the tail pipe, and the inner wall of the tail pipe 109 forms a smooth transition curved surface, so that energy loss caused by friction and collision between air flow and the inner wall of the tail pipe 109 is reduced, and the exhaust is smoother. The sound absorbing material is arranged in the catalyst back chamber 108 outside the tail pipe 109, and in the air flow discharging process in the tail pipe 109, high-frequency sound waves enter the catalyst back chamber 108 through the fourth through holes 602 and are dissipated by the sound absorbing material, so that high-frequency noise is reduced.

It should be noted that the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention, and the present invention can be replaced by equivalent technology. It is intended that all equivalent variations in the description and illustrations of the invention, or the direct or indirect application to other relevant art, be included within the scope of the invention.

Claims

1. The utility model provides a high-power diesel engine exhaust purification noise elimination integrated device which characterized in that: comprises a closed device cavity; a catalyst module is arranged in the device cavity; the catalyst module is tightly connected with the inner wall of the device cavity and divides the device cavity into a catalyst front bin and a catalyst rear bin; the device also comprises a tail gas inlet pipe; the tail gas inlet pipe extends into the catalyst front bin; a first isolation structure is arranged in the front catalyst bin and divides the front catalyst bin into a first bin and a second bin; the tail gas inlet pipe is arranged in the first bin, the end part of the tail gas inlet pipe is arranged on the first isolation structure, and the interior of the tail gas inlet pipe is communicated with the second bin through the end part of the tail gas inlet pipe; a first through hole is formed in the pipe wall of the tail gas inlet pipe; a movable isolation structure is arranged in the first bin; the movable isolation structure comprises a movable isolation plate which can move along the direction approaching to and away from the axis of the tail gas inlet pipe;

a first spherical cap shell is arranged on one side, facing the direction of the catalyst module, of the first isolation structure; the first spherical cap shell protrudes towards the direction of the catalyst module and covers the end part of the exhaust gas inlet pipe; a first air hole penetrating through the first spherical cap shell is formed in the first spherical cap shell;

a second spherical cap shell for accommodating the first spherical cap shell is arranged on one side of the first isolation structure, which faces the direction of the catalyst module; an air gap is arranged between the first spherical crown shell and the second spherical crown shell; a second air hole penetrating through the second spherical cap shell is formed in the second spherical cap shell; the first air holes and the second air holes are at least partially staggered;

the part of the tail gas inlet pipe adjacent to the first isolation structure is a tail section of the tail gas inlet pipe; the radial dimension of the cross section of the tail gas inlet pipe tail section perpendicular to the axis of the tail gas inlet pipe gradually increases along the tail gas flow direction.

2. The high-power diesel engine exhaust purification and silencing integrated device according to claim 1, wherein: a urea nozzle is arranged in the tail gas inlet pipe.

3. The high-power diesel engine exhaust purification and silencing integrated device according to claim 1, wherein: the device cavity is provided with a first driving mechanism for driving the movable isolation structure to move.

4. The high-power diesel engine exhaust purification and silencing integrated device according to claim 1, wherein: a second isolation structure is fixedly arranged between the catalyst module and the first isolation structure; a cylindrical straight pipe is arranged on the second isolation structure; the cylindrical straight pipe penetrates through the second isolation structure, and the axis of the cylindrical straight pipe is arranged along the connecting line direction of the first isolation structure and the catalyst module; the end part of the cylindrical straight pipe, which faces the first isolation structure, is an open end part, and the end part of the cylindrical straight pipe, which faces the catalyst module, is a closed end part; the cylindrical straight pipe is provided with a second through hole on a side wall of a portion between the second isolation structure and the catalyst module.

5. The high-power diesel engine exhaust purification and silencing integrated device according to claim 4, wherein: the number of the cylindrical straight pipes is larger than 1, and the axes of the cylindrical straight pipes are parallel.

6. The high-power diesel engine exhaust purification and silencing integrated device according to claim 4, wherein: the number of the second through holes is larger than 1; the diameter of the second through hole ranges from 8 mm to 15 mm; the perforation rate of the second through hole is more than 45%.

7. The high-power diesel engine exhaust purifying and silencing integrated device according to any one of claims 4 to 6, wherein: the cylindrical straight pipe is provided with a sliding isolation structure capable of sliding along the axial direction of the cylindrical straight pipe on the outer wall of the part between the first isolation structure and the second isolation structure; the sliding isolation structure is in sliding fit with the cylindrical straight pipe; the sliding isolation structure is in sliding fit with the inner wall of the device cavity.

8. The high-power diesel engine exhaust purification and silencing integrated device according to claim 7, wherein: a second driving mechanism is arranged for driving the sliding isolation structure to slide.

9. The high-power diesel engine exhaust purifying and silencing integrated device according to any one of claims 4 to 6, wherein: providing a perforated plate between the closed end of the tubular straight tube and the catalyst module; the perforated plate is provided with a third through hole; the perforated plate separates the closed end of the cylindrical straight tube from the catalyst module.

10. The high-power diesel engine exhaust purification and silencing integrated device according to claim 9, wherein: the number of the third through holes is larger than 1; the diameter range of the third through hole is 8-15 mm; the perforation rate of the third through hole is more than 50%.

11. The high-power diesel engine exhaust purification and silencing integrated device according to claim 1, wherein: a tail pipe is arranged in the catalyst rear bin; the tail pipe is provided with a tail pipe first end and a tail pipe second end for gas to enter and exit; the first end of the tail pipe is covered and communicated with a gas outlet on the catalyst module, and the second end of the tail pipe is communicated with the outside of the device cavity; the radial dimension of the tail pipe decreases stepwise from the tail pipe first end to the tail pipe second end.

12. The high-power diesel engine exhaust purification and silencing integrated device according to claim 11, wherein: a fourth through hole is provided in a side wall of the tail pipe.

13. The high-power diesel engine exhaust purifying and silencing integrated device according to claim 12, wherein: the number of the fourth through holes is larger than 1; the diameter range of the fourth through hole is 8-15 mm; the perforation rate of the fourth through hole is more than 50%.

14. The high-power diesel engine exhaust purification and silencing integrated device according to claim 11, wherein: and a sound absorption material is arranged between the tail pipe and the device cavity.