Stepped gas taking device for exhaust aftertreatment system

Abstract

The utility model relates to the technical field of engine tail gas treatment, in particular to a stepped gas taking device for an exhaust aftertreatment system. The gas taking device comprises a connecting pipe and a gas taking pipe; a mixing cavity is formed in the connecting pipe, air outlet holes are formed in the pipe wall of the connecting pipe, and the axes of the air outlet holes are perpendicular to the tail gas flow direction. One end of the air taking pipe is installed on the side face of the connecting pipe, at least two air taking holes are formed in the air facing face of the air taking pipe, air inlet channels with the same number as the air taking holes are arranged in the air taking pipe, the air inlet channels are isolated from one another, the head end of each air inlet channel is communicated with one air taking hole, and the tail ends of all the air inlet channels are communicated with the mixing cavity. According to the utility model, the problems that the measurement error of the nitrogen-oxygen sensor is caused by the interference of airflow in the gas taking pipe in the existing gas taking device and the gas outlet is easily invaded by the environment are solved, and the measurement precision and reliability of the nitrogen-oxygen sensor are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to engine tail gas treatment technical field especially, a kind of stepped gas taking device for exhaust aftertreatment system. BACKGROUND

[0002] In engine tail gas detection, nitrogen oxygen sensor is used to measure the NOx content in engine tail gas, and the gas taking end probe is arranged in the tail gas, and the NOx content in the tail gas is analyzed by sampling gas. The gas taking device is used to take representative sample gas from the exhaust tail pipe for nitrogen oxygen sensor measurement to realize accurate monitoring of tail gas composition, which is commonly used in exhaust aftertreatment system of internal combustion engine of automobile, motorcycle, engineering machinery and the like.

[0003] As the core component of the aftertreatment system, the measurement accuracy of the nitrogen oxygen sensor directly depends on whether the gas taking device can uniformly and independently collect tail gas samples at different positions and avoid external environmental interference. The widely used gas taking device is a cross-shaped gas taking pipe, as shown in Figure 1 、 Figure 2 A plurality of gas taking holes arranged in a line are provided on the gas taking pipe, and all the gas taking holes share one gas taking pipe channel. When installed, the gas taking pipe is integrally welded in the exhaust tail pipe, the nitrogen oxygen sensor is arranged on one side of the gas taking pipe, the gas taking holes face the direction of tail gas discharge, and the direction of the gas outlet of the gas taking pipe is parallel to the exhaust tail pipe. When working, the tail gas enters the shared gas taking pipe through the plurality of gas taking holes, mixes and then flows through the nitrogen oxygen sensor probe for detection, and finally is discharged from the gas outlet of the gas taking pipe.

[0004] The above-mentioned gas taking device has the problem that the plurality of gas taking holes share one gas taking pipe, and the gas flows taken by each gas taking hole will interfere with each other in the gas taking pipe. The main performance is that the gas flow taken by the gas taking hole close to the gas outlet of the gas taking pipe will hinder the gas flow taken by the gas taking hole far away from the gas outlet of the gas taking pipe. The gas flow taken by each gas taking hole has large difference in size, and in some cases, the gas taking hole at the far end does not take gas, so that the taken gas is not representative, and the mixed gas sample cannot truly reflect the composition of the tail gas, resulting in measurement error of the nitrogen oxygen sensor. In addition, the direction of the gas outlet of the gas taking device is parallel to the exhaust tail pipe and directly opposite the tail pipe outlet. In rainy weather, waterlogged road conditions or when washing the car, external water droplets may enter the inside of the gas taking pipe through the gas outlet in the opposite direction, causing the nitrogen oxygen sensor probe to burst when encountering water, reducing the measurement reliability and service life. UTILITY MODEL CONTENTS

[0005] In view of the deficiencies of the prior art, the purpose of the embodiments of the utility model is to provide a stepped gas taking device for exhaust aftertreatment system to solve the problem of nitrogen oxygen sensor measurement error caused by gas flow interference in the gas taking pipe of the existing gas taking device and the problem that the gas outlet is easily invaded by the environment, improve the measurement accuracy and reliability of the nitrogen oxygen sensor, and prolong the service life of the nitrogen oxygen sensor.

[0006] To achieve the above object, the utility model embodiment provides the following technical scheme:

[0007] A kind of stepped air taking device for exhaust aftertreatment system, comprising: connecting pipe and air taking pipe;The mixing cavity is provided in the connecting pipe, and the pipe wall of the connecting pipe is provided with air outlet hole, and the axis of the air outlet hole is perpendicular to exhaust gas flow direction;One end of the air taking pipe is installed on the side of connecting pipe, and at least two air taking holes are provided on the air-facing surface of the air taking pipe, the same number of air inlet channels as the air taking hole is provided in the air taking pipe, and each air inlet channel is isolated from each other, the leading end of each air inlet channel is communicated with an air taking hole, and the trailing end of all air inlet channels is communicated with the mixing cavity.

[0008] Optionally, the air taking hole on the air taking pipe close to the connecting pipe position is in front in the exhaust gas flow direction compared with the air taking hole away from the connecting pipe position.

[0009] Optionally, the air-facing surface of the air taking pipe is a stepped surface, and along the gas flow direction in the air inlet channel, the width of the air taking pipe in the exhaust gas flow direction becomes larger and larger.

[0010] Optionally, the air-facing surface of the air taking pipe is an inclined surface, and along the gas flow direction in the air inlet channel, the width of the air taking pipe in the exhaust gas flow direction becomes larger and larger.

[0011] Optionally, the connecting pipe comprises a first pipe body and a second pipe body, and the air taking pipe is provided with a plurality of air taking pipes, and the plurality of air taking pipes are arranged on the end surface and the side surface of the first pipe body respectively, a plurality of air inlet holes are formed on each air taking pipe, and the second pipe body is located at the other end of the first pipe body.

[0012] Optionally, the air outlet hole is formed on the second pipe body, and is symmetrically arranged on both sides of the pipe wall of the second pipe body.

[0013] Optionally, a nitrogen oxygen sensor is installed in the second pipe body, and the probe of the nitrogen oxygen sensor is inserted into the mixing cavity.

[0014] Optionally, a support plate is arranged at the end of the air taking pipe away from the connecting pipe, and the outer side surface of the support plate is connected to the inner wall of the exhaust tail pipe.

[0015] Optionally, the both ends of the support plate are provided with bending parts, and the bending parts are bent towards the air taking pipe.

[0016] Optionally, the support plate is welded, bonded or detachably connected to the inner wall of the exhaust tail pipe.

[0017] One or more technical solutions provided in the utility model embodiment have at least the following technical effects or advantages:

[0018] 1. The stepped gas taking device adopts a combined design of a connecting pipe and a gas taking pipe, a mixing chamber is built inside the connecting pipe, one end of the gas taking pipe is firmly installed on the side of the connecting pipe, at least two gas taking holes are arranged on the gas receiving surface of the gas taking pipe, a number of air inlet channels consistent with the gas taking holes are arranged inside the gas taking pipe, the air inlet channels are isolated from each other, the leading end of each air inlet channel is in communication with a gas taking hole, and the trailing ends of all the air inlet channels are in communication with the mixing chamber. This unique structure design enables the gas taking holes to be completely independent during the gas taking process, effectively avoids the mutual interference between the gas flows, ensures the uniformity of the gas taking amount, and further greatly improves the measurement accuracy of the nitrogen oxygen sensor, thereby providing more accurate and reliable data support for the exhaust emission detection.

[0019] 2. The gas outlet hole is arranged on the pipe wall, and the axis of the gas outlet hole is perpendicular to the direction of the exhaust gas flow, thereby effectively preventing external moisture and impurities from directly falling into the mixing chamber, and significantly improving the reliability and stability of the device in harsh weather or special working conditions.

[0020] The advantages of the additional aspects of the present application will be given in the following description, some of which will become apparent from the following description, or will be understood by those skilled in the art through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments described in the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor. In addition, the mutual distance or size is exaggerated to show the position of each component, and the schematic diagram is only used for illustration.

[0022] Figure 1 is a schematic diagram of the existing gas taking device;

[0023] Figure 2 is a schematic diagram of the existing gas taking device installed in the gas distribution tail pipe;

[0024] Figure 3 is an explosion schematic diagram of the gas taking device provided by the embodiment of the present application;

[0025] Figure 4 is a schematic diagram of two sides of the gas taking device provided by the embodiment of the present application;

[0026] Figure 5 is a schematic diagram of the gas taking device installed in the gas distribution tail pipe provided by the embodiment of the present application;

[0027] Figure 6 is a schematic diagram of the working principle of a single gas taking pipe provided by the embodiment of the present application;

[0028] Figure 7 is a schematic diagram of the working principle of the whole gas taking device provided in the embodiments of the present application;

[0029] In the figure: 1, gas taking device; 11, connecting pipe; 111, gas outlet hole; 112, mixing cavity; 12, supporting plate; 13, gas taking pipe; 131, gas inlet hole; 132, gas inlet channel; 2, nitrogen oxygen sensor; 3, exhaust tail pipe; DETAILED DESCRIPTION

[0030] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. In addition, it should be understood that the terms "comprise" and / or "include" as used herein indicate the presence of a feature, step, operation, device, component and / or combinations thereof.

[0031] Embodiment 1

[0032] The present embodiment proposes a stepped gas taking device 1 for exhaust aftertreatment system, which eliminates the mutual interference during multi-hole gas taking through independent gas flow channel design, ensures uniform gas sample collection of each gas taking hole, thereby improving the measurement accuracy of nitrogen oxygen sensor 2; at the same time, the layout direction of gas outlet hole 111 is optimized to avoid the intrusion of external impurities into gas taking device 1, thereby enhancing the system reliability and durability.

[0033] As shown in Figure 3 , Figure 4 , the gas taking device 1 comprises a connecting pipe 11 and a gas taking pipe 13; the connecting pipe 11 is provided with a mixing cavity 112 (as shown in Figure 6 ), the connecting pipe 11 is provided with a gas outlet hole 111 on the pipe wall, the axis of the gas outlet hole 111 is perpendicular to the direction of the exhaust gas flow; one end of the gas taking pipe 13 is installed on the side of the connecting pipe 11, the gas taking pipe 13 is provided with at least two gas taking holes on the gas-facing surface, the gas taking pipe 13 is provided with the same number of gas inlet channels 132 as the gas taking holes, each gas inlet channel 132 is isolated from each other, the leading end of each gas inlet channel 132 is in communication with one gas taking hole, and the trailing end of all gas inlet channels 132 is in communication with the mixing cavity 112.

[0034] Each gas inlet hole of the gas taking device 1 corresponds to an air inlet channel 132, and each gas inlet hole can independently take gas compared with the existing cross-shaped gas taking frame. The gas taken by each gas inlet hole does not affect each other, and the amount of gas taken is equivalent. Therefore, the gas taken by the gas taking device 1 is more representative, the measurement value of the nitrogen oxygen sensor 2 is closer to the actual value, and the measurement accuracy of the nitrogen oxygen sensor 2 is improved. In addition, the air outlet hole 111 above the mixing chamber 112 is located on the side and is close to vertical with the direction of the tail pipe, which can avoid rain and sundries entering the mixing chamber 112 from the air outlet hole 111, causing damage to the nitrogen oxygen sensor 2.

[0035] The gas inlet hole on the gas taking pipe 13 close to the connecting pipe 11 is in front in the direction of the tail gas flow compared with the gas inlet hole far from the connecting pipe 11.

[0036] The gas inlet holes are arranged in a stepped manner along the direction of the tail gas flow, so that the distal gas inlet hole can still effectively obtain the gas flow, avoid insufficient gas taking due to distance difference, ensure that the gas flow taken by each gas inlet hole can truly reflect the state of the tail gas at different positions, further improve the representativeness of gas taking, provide the nitrogen oxygen sensor 2 with a gas flow sample with more analysis value, and make the measurement result more accurately reflect the NOx content in the tail gas, which is conducive to comprehensive and accurate monitoring and evaluation of the tail gas emission condition.

[0037] The gas taking pipe 13 has a stepped surface facing the gas, and along the direction of the gas flow in the air inlet channel 132, the width of the gas taking pipe 13 in the direction of the tail gas flow becomes larger and larger. The stepped surface forms a multi-stage flow guide structure, guides the tail gas to flow into different gas inlet holes in layers, reduces the turbulence of the gas flow on the surface of the gas taking pipe 13, makes the air intake of each gas inlet hole more stable, and at the same time ensures the physical isolation of the air inlet channel 132.

[0038] Of course, it can be understood that in another embodiment, the gas taking pipe 13 can also have an inclined surface facing the gas, and along the direction of the gas flow in the air inlet channel 132, the width of the gas taking pipe 13 in the direction of the tail gas flow becomes larger and larger.

[0039] The connecting pipe 11 includes a first pipe body and a second pipe body, and the gas taking pipe 13 has a plurality of gas taking pipes 13 arranged on the end surface and the side surface of the first pipe body, respectively. A plurality of air inlet holes 131 are formed on each gas taking pipe 13, and the second pipe body is located at the other end of the first pipe body.

[0040] The connecting pipe 11 adopts a combination of a first pipe body and a second pipe body. The first pipe body undertakes the main connection and support functions, while the second pipe body is used to install key detection elements. Specifically, there are three air intake pipes 13, which are installed on the end face and two sides of the first pipe body, respectively. This multi-directional layout fully considers the multi-dimensional flow characteristics of exhaust gas in the exhaust tailpipe 3, enabling comprehensive air intake of different areas of the exhaust gas, making the air samples more representative and comprehensive. Each air intake pipe 13 has three air inlets 131, further refining the distribution of air intake points. This structural design not only enhances the overall stability of the air intake device 1, but also optimizes the convergence and guidance path of the airflow, providing strong structural support for improving the comprehensive performance of the air intake device 1 and meeting the diverse needs of actual exhaust gas treatment conditions.

[0041] It is understandable that in other embodiments, the first or second tube may also be of other shapes, such as elliptical, rectangular, trapezoidal, etc. Each air intake tube 13 may also have two, four, or five air inlets 131.

[0042] The air outlet 111 is located on the second pipe body and symmetrically arranged on both sides of the pipe wall. Since the second pipe body collects the mixed airflow from multiple air intake pipes 13, symmetrically discharging it from both sides effectively prevents airflow deviation or vortex phenomena within the second pipe body, ensuring that the mixed airflow is discharged from the device uniformly and stably. Simultaneously, this symmetrical layout also helps maintain the overall balance and stability of the air intake device 1 within the exhaust tailpipe 3, reducing adverse effects on the device caused by airflow impact or vibration, and further improving the reliability of the device.

[0043] The air intake and / or air outlet 111 can be square or round. A square air intake provides a larger intake area, which helps increase airflow rate and velocity, improving intake and discharge efficiency. A round air outlet 111, on the other hand, has lower airflow resistance and a more uniform flow velocity distribution, effectively reducing turbulence and impact at the orifice opening, and improving discharge stability. Of course, it is understood that the air intake or outlet can also be other shapes, such as elongated holes, elliptical holes, triangular holes, etc. Those skilled in the art can flexibly configure these shapes according to different application scenarios to better meet the diverse needs of actual exhaust gas treatment processes.

[0044] like Figure 3 , Figure 5 As shown, a nitrogen-oxygen sensor 2 is installed in the second tube. The probe of the nitrogen-oxygen sensor 2 is inserted into the mixing chamber 112. The nitrogen-oxygen sensor 2 can directly contact the fully mixed exhaust gas sample, providing the most favorable conditions for accurately measuring the NOx content in the exhaust gas.

[0045] The support plate 12 is provided at one end of the gas taking pipe 13 away from the connecting pipe 11, and the components are connected by welding.

[0046] The support plate 12 provides a more stable installation basis for the gas taking device 1, effectively enhancing the vibration resistance and structural stability of the entire device in the exhaust tail pipe 3. Since the exhaust system will produce certain vibration and airflow impact during operation, the support plate 12 can evenly distribute the external force received by the gas taking device 1 to the pipe wall of the exhaust tail pipe 3, avoiding the problem of device damage or falling due to excessive local stress.

[0047] Further, the support plate 12 has a bending portion at both ends, which bends towards the gas taking pipe 13. The bending portion increases the contact area with the exhaust tail pipe, also enhances the strength and stability of the support plate, better disperses and transmits external force, improves the reliability of the gas taking device under harsh working conditions, ensures its stability and measurement accuracy during long-term use, and prolongs the service life.

[0048] The support plate 12, as a key component of the gas taking device, its connection method directly affects the stability, reliability and installation and maintenance convenience of the device. The specific connection method can adopt welding, bonding or detachable connection, etc. The welding method forms a firm and non-detachable connection by high-temperature fusion of metal, which can withstand large vibration and airflow impact. The bonding method uses high-temperature resistant glue, which avoids the problem of heat stress concentration caused by welding, and provides good sealing. The detachable connection (such as bolt connection or buckle connection) provides flexibility in installation and maintenance, facilitating quick disassembly and reinstallation when replacement or maintenance is needed, especially suitable for scenarios that require regular maintenance. The person skilled in the art can make reasonable selection according to different application scenarios.

[0049] In summary, by using the mutually independent air inlet channels 132 to split the air taken by each air taking hole, the mutual influence between air flows is avoided, ensuring that each air taking hole can take air, and the air quantity is equivalent, achieving the purpose of multi-point air taking. Moreover, the air outlet hole 111 above the mixing chamber 112 is located on both sides and arranged vertically to the tail pipe direction, avoiding rain splashing into the mixing chamber 112 and causing damage to the nitrogen oxygen sensor 2 probe.

[0050] Example 2

[0051] The working method of the stepped gas taking device 1 described in embodiment 1 is provided, first, the gas flow at each gas taking hole is stably flowed along the corresponding gas inlet channel 132 under the pushing of the tail gas flow. Since each gas taking hole has an independent gas inlet channel 132, the gas flows do not interfere with each other, ensuring the uniformity and representativeness of the gas taking. Then, the gas flows from different positions are converged through the gas inlet channel 132 and smoothly enter the mixing chamber 112. In the mixing chamber 112, the gas flows from different positions are fully mixed to form a uniform mixed gas flow. Subsequently, the mixed gas flow flows through the probe of the nitrogen oxygen sensor 2. The probe of the nitrogen oxygen sensor 2 accurately measures the NOx component in the mixed gas flow, converts the NOx content in the tail gas into an electrical signal output, and provides key data support for tail gas emission monitoring. Finally, the measured gas flow is discharged through the gas outlet hole 111.

[0052] As shown in Figure 6 , the working principle of a single gas taking pipe 13 is that when the gas flow flows into the tail pipe, part of the gas flow enters the gas inlet channel 132 through the gas taking hole of the gas taking pipe 13, and then flows into the mixing chamber 112 through the gas inlet channel 132. Each gas taking hole corresponds to a gas inlet channel 132 to ensure that the gas flows taken by each gas taking hole are independent and do not affect each other.

[0053] As shown in Figure 7 , the working principle of the entire stepped gas taking device 1 is that the gas flows from different positions are converged to the mixing chamber 112 through the gas taking pipe 13, and are mixed at the bottom of the mixing chamber 112. After mixing, the mixed gas continues to flow through the probe of the nitrogen oxygen sensor 2 to complete the measurement of the NOx component, and then flows out through the gas outlet hole 111 above the mixing chamber 112. The gas outlet hole 111 is located on both sides of the mixing chamber 112 and is arranged vertically to the direction of the tail pipe to avoid rainwater and other impurities outside the tail pipe from splashing into the mixing chamber 112 through the gas outlet hole 111 of the mixing chamber 112, which can effectively reduce the risk of damage to the probe of the nitrogen oxygen sensor 2.

[0054] The entire working process is closely linked and cooperates with each other to form a complete closed loop system, ensuring that the entire process of tail gas sampling, mixing, detection and discharge is efficiently and stably carried out, and providing strong support for realizing accurate monitoring and effective control of tail gas emission.

[0055] Although the specific embodiments of the utility model have been described in combination with the drawings, it is not a limitation on the protection scope of the utility model, and those skilled in the art should understand that various modifications or deformations made by those skilled in the art on the basis of the technical solutions of the utility model without creative labor are still within the protection scope of the utility model.

Claims

1. A stepped air intake device for an exhaust aftertreatment system, characterized in that, include: Connecting pipe and air intake pipe; The connecting pipe is provided with a mixing chamber, and the pipe wall of the connecting pipe is provided with an air outlet, the axis of which is perpendicular to the exhaust gas flow direction. One end of the gas intake pipe is installed on the side of the connecting pipe. At least two gas intake holes are provided on the air-facing surface of the gas intake pipe. The gas intake pipe is provided with the same number of air intake channels as the gas intake holes. Each air intake channel is isolated from each other. The first end of each air intake channel is connected to a gas intake hole. The tail ends of all air intake channels are connected to the mixing chamber.

2. The stepped gas extraction device as described in claim 1, characterized in that, The air intake port on the air intake pipe that is closer to the connecting pipe is forward in the direction of exhaust gas flow compared to the air intake port that is farther away from the connecting pipe.

3. The stepped gas extraction device as described in claim 2, characterized in that, The air intake pipe has a stepped surface on its front side, and its width increases along the airflow direction in the exhaust gas flow direction.

4. The stepped gas extraction device as described in claim 2, characterized in that, The air intake pipe has an inclined surface facing the air, and its width increases along the airflow direction in the exhaust gas airflow direction.

5. The stepped gas extraction device as described in claim 1, characterized in that, The connecting pipe includes a first pipe body and a second pipe body. There are multiple air intake pipes, which are respectively disposed on the end face and side face of the first pipe body. Multiple air intake holes are opened on each air intake pipe. The second pipe body is located at the other end of the first pipe body.

6. The stepped gas extraction device as described in claim 5, characterized in that, The air outlet is located on the second pipe body and is symmetrically arranged on both sides of the pipe wall.

7. The stepped gas extraction device as described in claim 5, characterized in that, A nitrogen-oxygen sensor is installed in the second tube, and the probe of the nitrogen-oxygen sensor is inserted into the mixing chamber.

8. The stepped gas extraction device as described in claim 1, characterized in that, A support plate is provided at the end of the air intake pipe away from the connecting pipe, and the outer side of the support plate is connected to the inner wall of the exhaust tailpipe.

9. The stepped gas extraction device as described in claim 8, characterized in that, Both ends of the support plate are provided with bent portions, which are bent toward the air intake pipe.

10. The stepped gas extraction device as described in claim 8, characterized in that, The support plate is welded, bonded, or detachably connected to the inner wall of the exhaust tailpipe.

Images