Rear cavity structure for improving rear nitrogen oxide measurement accuracy

Abstract

The invention discloses a rear cavity structure for improving rear nitrogen oxide measurement accuracy. The rear cavity structure comprises a circular cylinder and a cyclone pipe, one end of the circular cylinder is open as an air inlet; flow mixing fins are arranged on the part, extending into the circular barrel, of the cyclone pipe, and flow guide holes corresponding to the flow mixing fins are formed in the side wall of the cyclone pipe, so that gas in the circular barrel is secondarily mixed and then stably guided into the cyclone pipe; the end part, extending out of the circular barrel, of the cyclone pipe is opened and serves as an air outlet; a nitrogen-oxygen sensor is arranged at the part, extending out of the circular barrel, of the cyclone pipe and is used for detecting nitrogen-oxygen compound data at the air outlet. According to the rear cavity structure, nitrogen oxide and tail gas can be fully mixed for the second time, nitrogen oxide data can be accurately and stably detected, it is ensured that the harmful ingredient nitrogen oxide of the diesel engine is reduced into nitrogen and water, the detection data of the nitrogen oxide is fed back to a controller, injection parameters are accurately corrected, and the injection efficiency is improved. Therefore, the conversion efficiency of the catalytic converter is improved, and the emission index is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engine exhaust treatment systems, and in particular to a rear cavity structure for improving the measurement accuracy of post-nitrogen oxides. Background Art

[0002] With the development of diesel engine technology, eliminating nitrogen oxides in diesel engine exhaust is one of the post-treatment technologies. Urea aqueous solution is sprayed into the post-treatment through the urea nozzle, and a thermal decomposition reaction occurs within a sufficient temperature to produce the required reducing agent ammonia (NH3). Under the action of the catalyst carrier, ammonia reacts with nitrogen oxides (NO X ) reaction to achieve the purpose of eliminating nitrogen oxides, which are harmful emissions from diesel engines.

[0003] The gas in the rear cavity passes through the SCR to the rear cavity, and the exhaust tail pipe on the rear cavity does not disturb the gas structure, which easily causes the gas in the tail pipe to be eccentric, so that the parameters measured by the nitrogen oxide sensor detection probe only represent the local concentration, resulting in nitrogen oxides (NO X )’s detection parameters deviate from the overall real data; this causes the signal fed back to the controller to be inaccurate, making it impossible to accurately correct the injection parameters, thus resulting in excessive emissions. Summary of the invention

[0004] The object of the present invention is to provide a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement, so as to solve the problem of inaccurate nitrogen oxide detection parameters of existing catalytic converters, resulting in excessive emissions.

[0005] In order to solve the above technical problems, the present invention provides a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement, comprising a circular cylinder and a cyclone; the cyclone is vertically arranged in the circular cylinder; One end of the circular cylinder is open to serve as an air inlet; The portion of the swirl tube extending into the circular cylinder is provided with a mixing fin, and a guide hole is provided on the side wall of the swirl tube corresponding to the mixing fin, so that the gas in the circular cylinder is secondary mixed and then stably introduced into the swirl tube; The end of the cyclone tube extending outside the circular cylinder is open and serves as an air outlet; The portion of the cyclone tube extending outside the circular cylinder is provided with a nitrogen oxide sensor for detecting nitrogen oxide compound data at the air outlet.

[0006] Preferably, one end of the circular cylinder is an air inlet, and the other end is closed by a circular end cover, so that the gas in the circular cylinder flows toward the cyclone tube.

[0007] Preferably, one end of the cyclone tube is an air outlet, and the other end is closed by a plugging cover, so that the gas in the cyclone tube flows toward the air outlet.

[0008] Preferably, the plugging cover at the end of the swirl tube is fixedly connected to the inner wall of the circular cylinder; the swirl tube extending outward is fixed to the flange hole of the circular cylinder by welding.

[0009] Preferably, the mixed flow fins are provided in plurality and are evenly distributed around the central axis of the swirl tube.

[0010] Preferably, the plurality of mixed flow fins are formed by stamping and bending the side wall of the swirl tube, and a plurality of guide holes are formed correspondingly.

[0011] Preferably, the mixed flow fin is tangent to the side wall of the swirl tube to form an angle α.

[0012] Preferably, the angle α is in the range of 20° to 50°.

[0013] Preferably, the length of the mixed flow fin accounts for 50% to 75% of the total length of the vortex tube.

[0014] Preferably, a mounting hole is provided on the cyclone tube for mounting a nitrogen oxide sensor, and a detection probe of the nitrogen oxide sensor extends through the mounting hole to the interior of the cyclone tube.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The rear cavity structure that improves the accuracy of post-nitrogen oxide measurement can fully mix nitrogen oxide with exhaust gas for the second time, and accurately and stably detect nitrogen oxide compound data, ensuring that nitrogen oxide, a harmful component of diesel engine, is eliminated and reduced to nitrogen and water; 2. The rear cavity structure can feed back the detection data of nitrogen oxides to the controller, accurately correct the injection parameters, thereby improving the conversion efficiency of the catalytic converter and ensuring emission indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement provided by the present invention; Figure 2 It is a front view of a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement provided by the present invention; Figure 3 It is a side view of a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement provided by the present invention; Figure 4 It is a top view of a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement provided by the present invention; Figure 5is a front view of the cyclone tube provided by the present invention; Figure 6 It is a top view of the cyclone tube provided by the present invention.

[0017] In the figure: 1, circular cylinder; 101, air inlet; 102, circular end cover; 103, flange hole; 2. swirl tube; 201. mixed flow fin; 202. air outlet; 203. plugging cover; 204. mounting hole; 3. Nitrogen oxygen sensor; 301. Detection probe. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are in very simplified form and in non-precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0021] In addition, the features, operations, and characteristics described in the specification can be combined in any appropriate manner to form various embodiments. Similarly, the steps or actions described in the method can also be adjusted in order in a manner that can be easily seen by those skilled in the art. Therefore, the various sequences in the specification and drawings are only for the purpose of describing a certain embodiment, and are not necessarily such sequences, unless otherwise stated that a certain sequence must be followed. Example

[0022] The present invention provides a rear cavity structure for improving the accuracy of post-nitrogen oxide measurement, see Figure 1-4 , comprising a circular cylinder 1 and a swirl tube 2; the swirl tube 2 is vertically arranged in the circular cylinder 1; one end of the circular cylinder 1 is open, serving as an air inlet 101; the portion of the swirl tube 2 extending into the circular cylinder 1 is provided with a mixing fin 201, and a guide hole is provided on the side wall of the swirl tube 2 corresponding to the mixing fin 201, so that the gas in the circular cylinder 1 is secondary mixed and then stably introduced into the swirl tube 2; the end of the swirl tube 2 extending outside the circular cylinder 1 is open, serving as an air outlet 202; the portion of the swirl tube 2 extending outside the circular cylinder 1 is provided with a nitrogen oxide sensor 3 for detecting nitrogen oxide compound data at the air outlet.

[0023] Specifically, one end of the circular cylinder 1 is an air inlet 101 , and the other end is closed by a circular end cover 102 , so that the gas in the circular cylinder 1 flows toward the cyclone tube 2 .

[0024] Furthermore, one end of the cyclone tube 2 is an air outlet 202 , and the other end is closed by a plugging cover 203 , so that the gas in the cyclone tube 2 flows toward the air outlet 202 .

[0025] In this embodiment, the plugging cover 202 at the end of the cyclone 2 is fixedly connected to the inner wall of the circular cylinder 1 ; the cyclone 2 extending outward is fixedly welded to the flange hole 103 of the circular cylinder 1 .

[0026] Specifically, Figure 5 As shown, the mixed flow fins 201 are provided in multiple pieces and are evenly distributed around the central axis of the vortex tube 2. The multiple mixed flow fins 201 are formed by stamping and bending the side walls of the vortex tube 2, and a plurality of guide holes are formed correspondingly.

[0027] Further, such as Figure 6 As shown, the mixed flow fin 201 is tangent to the side wall of the vortex tube 2 to form an angle α, wherein the angle α is in the range of 20° to 50°.

[0028] In this embodiment, the length of the mixed flow fin 201 accounts for 50% to 75% of the total length of the vortex tube 2 .

[0029] Specifically, a mounting hole 204 is provided on the cyclone tube 2 for mounting the nitrogen oxide sensor 3 , and a detection probe 301 of the nitrogen oxide sensor 3 passes through the mounting hole 204 and extends into the interior of the cyclone tube 2 .

[0030] The rear cavity structure that improves the accuracy of post-nitrogen oxide measurement can fully mix nitrogen oxides with exhaust gas for a second time, and accurately and stably detect nitrogen oxide compound data, ensuring the elimination of nitrogen oxides, harmful components of diesel engines, and reducing them to nitrogen and water; and the detection data of nitrogen oxides is fed back to the controller to accurately correct the injection parameters, thereby improving the conversion efficiency of the catalytic converter and ensuring emission indicators.

[0031] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement, characterized in that: It comprises a circular cylinder (1) and a cyclone tube (2); the cyclone tube (2) is vertically arranged in the circular cylinder (1); One end of the circular cylinder (1) is open and serves as an air inlet (101); The portion of the swirl tube (2) extending into the circular cylinder (1) is provided with a mixing fin (201), and a guide hole is provided on the side wall of the swirl tube (2) corresponding to the mixing fin (201), so that the gas in the circular cylinder (1) is secondary mixed and then stably introduced into the swirl tube (2); The end of the cyclone tube (2) extending outside the circular cylinder (1) is open and serves as an air outlet (202); The portion of the cyclone tube (2) extending outside the circular cylinder (1) is provided with a nitrogen oxide sensor (3) for detecting nitrogen oxide compound data at the air outlet.

2. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 1, characterized in that: One end of the circular cylinder (1) is an air inlet (101), and the other end is closed by a circular end cover (102), so that the gas in the circular cylinder (1) flows toward the cyclone tube (2).

3. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 1, characterized in that: One end of the cyclone tube (2) is an air outlet (202), and the other end is closed by a plugging cover (203), so that the gas in the cyclone tube (2) flows towards the air outlet (202).

4. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 3, characterized in that: The plugging cover (202) at the end of the cyclone tube (2) is fixedly connected to the inner wall of the circular cylinder (1); the cyclone tube (2) extending outward is fixedly welded to the flanged hole (103) of the circular cylinder (1).

5. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 1, characterized in that: The mixed flow fins (201) are provided in plurality and are evenly distributed around the central axis of the swirl tube (2).

6. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 5, characterized in that: The plurality of mixed flow fins (201) are formed by stamping and bending the side wall of the swirl tube (2), and a plurality of guide holes are formed correspondingly.

7. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 6, characterized in that: The mixed flow fin (201) is tangent to the side wall of the swirl tube (2) to form an angle α.

8. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 7, characterized in that: The angle α ranges from 20° to 50°.

9. A rear cavity structure for improving the accuracy of post-nitrogen oxide measurement as claimed in claim 7, characterized in that: The length of the mixed flow fin (201) accounts for 50% to 75% of the total length of the cyclone tube (2).

10. The rear cavity structure for improving the accuracy of post-nitrogen oxide measurement according to claim 1, characterized in that: The cyclone tube (2) is provided with a mounting hole (204) for mounting a nitrogen oxide sensor (3), and a detection probe (301) of the nitrogen oxide sensor (3) passes through the mounting hole (204) and extends into the interior of the cyclone tube (2).

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