Exhaust port urea crystal detection mechanism and detection method

Abstract

The present invention relates to the field of urea crystal detection, specifically to an exhaust port urea crystal detection mechanism and a detection method. Among them, the detection mechanism includes a device for detecting urea crystals in an exhaust pipe, and the detection mechanism includes a crystal concentrator, a rebound guide platform, a hanging assembly, a crystal detector and an ECU; the crystal concentrator includes a collecting bucket, an extension tube and a guide cylinder connected in sequence, the inner surface of the collecting bucket is an attachment guide surface for urea crystals to attach, and the inner side of the guide cylinder has a collecting cavity; the hanging assembly is connected between the crystal concentrator and the inner surface of the exhaust pipe; the rebound guide platform is located in the middle of the guide cylinder and forms an airflow channel with the inner circumference of the guide cylinder, and the rebound guide platform has a rebound guide conical surface that rebounds the urea crystals blown from the attachment guide surface into the collecting cavity and guides the exhaust gas flow to the airflow channel. The present invention accumulates urea crystals, and can accurately detect them using only one crystal detector, thereby reducing the detection cost.

Description

Technical Field

[0001] The invention relates to the field of urea crystal detection, and in particular to an exhaust port urea crystal detection mechanism and a detection method. Background Art

[0002] The core of the Selective Catalytic Reduction (SCR) technology route is to use pyrolysis and hydrolysis of urea aqueous solution to produce NH3, which is used as a reducing agent to react with NO. x Reaction, thereby producing N2 and H2O. Since the urea solution may not be pyrolyzed in time, the water will evaporate under the influence of exhaust gas flow and heat, gradually forming intermediate products such as cyanic acid, biuret, and cyanuric acid, forming deposits such as urea crystal stones, which will continue to accumulate and block the exhaust pipe, resulting in increased exhaust back pressure and reduced engine power.

[0003] Chinese patent publication number CN212989156U discloses a urea crystal detection device in an SCR assembly, in which at least one transceiver is arranged on a crystallization-prone pipeline in the SCR assembly, and a detection signal is transmitted in real time to a receiving device in the same group through a transmitting device in the transceiver. The ECU determines whether urea crystals exist in the SCR assembly based on the detection signal received by the receiving device, which can improve the accuracy of urea crystal detection of the SCR assembly.

[0004] However, the above technical solution has the following disadvantages: urea crystals are detected in multiple directions through multiple sets of transmitting devices and dispersing devices, resulting in high detection costs. Summary of the invention

[0005] The purpose of the present invention is to address the problems existing in the background technology and to propose a urea crystal detection mechanism and method for an exhaust port. The urea crystals can be accurately detected by accumulating them and using only one crystal detector, thereby reducing the detection cost.

[0006] On the one hand, the present invention proposes an exhaust port urea crystal detection mechanism for detecting urea crystals in an exhaust pipe, the detection mechanism comprising a crystal concentrator, a rebound guide table, a hanging assembly, a crystal detector and an ECU (on-board computer).

[0007] The crystallization concentrator is located on the inner side of the exhaust pipe. The crystallization concentrator includes a collecting bucket portion, an extension tube portion and a guide cylinder portion which are connected in sequence. The inner surface of the collecting bucket portion is an attachment guide surface for urea crystals to attach to. The opening size of the extension tube portion gradually increases in the direction away from the collecting bucket portion. The inner side of the guide cylinder portion is provided with a collecting cavity, and one end of the collecting cavity facing the extension tube portion is open and the other end opposite to the collection cavity is closed.

[0008] The hanging assembly is connected between the crystallization concentrator and the inner surface of the exhaust pipe, and makes the crystallization concentrator vibrate when the exhaust gas blows to the crystallization concentrator, and the exhaust gas blows the urea crystals shaken off the crystallization concentrator along the attached guide surface.

[0009] The rebound guide platform is located in the middle of the guide cylinder and forms an airflow channel with the inner circumference of the guide cylinder. The rebound guide platform has a rebound guide conical surface that rebounds urea crystals blown from the attached guide surface into the collection cavity and guides the exhaust gas flow to the airflow channel.

[0010] The crystal detector is arranged in the collecting chamber, and detects whether urea crystals are accumulated in the collecting chamber by means of photoelectric detection; a signal transmitter is connected between the ECU and the crystal detector for communication.

[0011] Preferably, a plurality of collecting buckets are evenly distributed around the central axis of the crystallization concentrator, an exhaust gas channel is formed between two adjacent collecting buckets, and the collecting buckets are gradually inclined outward in a direction away from the expansion tube portion.

[0012] Preferably, the collecting bucket portion comprises a collecting plate portion and two baffle portions respectively connected to both sides of the collecting plate portion, and the baffle portions face the inner side of the collecting bucket portion.

[0013] Preferably, the collecting plate portion is an arc-shaped plate convex outwardly in a direction away from the central axis of the crystallization concentrator.

[0014] Preferably, the attachment guide surface is the inner surface of the collecting plate portion, and the attachment guide surface faces the rebound guide conical surface.

[0015] Preferably, the collecting chamber is an annular chamber, and the axial depth of the collecting chamber gradually increases from top to bottom.

[0016] Preferably, the crystallization detector comprises a mounting tube mounted at the inner bottom of the collecting chamber and a photoelectric sensor disposed in the mounting tube and facing the deepest part of the inner bottom of the collecting chamber.

[0017] Preferably, a bracket for mounting the rebound guide platform is provided on the inner circumferential surface of the guide cylinder.

[0018] Preferably, the hanging assembly includes three groups of hanging assemblies, two groups of hanging assemblies are connected between the top of the crystallization concentrator and the top of the inner surface of the exhaust pipe and are distributed side by side, and the other group of hanging assemblies is connected between the bottom of the crystallization concentrator and the bottom of the inner surface of the exhaust pipe; the hanging assembly includes a fixed table a connected to the inner surface of the exhaust pipe, a connecting table a connected to the fixed table a, a fixed table b connected to the outer surface of the crystallization concentrator, a connecting table b connected to the fixed table b, and a heat-resistant rope connected between the connecting table a and the connecting table b, the heat-resistant rope in the hanging assembly located above the crystallization concentrator is in a taut state, and the heat-resistant rope in the hanging assembly located below the crystallization concentrator is in a loose state.

[0019] On the other hand, the present invention provides a detection method for the exhaust port urea crystal detection mechanism, the method comprising the following steps:

[0020] S1. Use the lifting assembly to hang the crystal concentrator on the inner side of the exhaust pipe;

[0021] S2, urea crystals are formed on the attached guide surface of the crystal concentrator and gradually accumulate and increase;

[0022] S3. When the vehicle is running, the exhaust gas flows in the exhaust pipe, and the exhaust gas blows the crystal concentrator to vibrate. The vibration of the crystal concentrator combined with the blowing force of the exhaust gas shakes off the urea crystals that have accumulated and cannot be attached to the attachment guide surface, and blows the shaken off urea crystals backward along the attachment guide surface, and the urea crystals flow backward with the exhaust gas;

[0023] S4, urea crystals are bounced outwards by the rebound guide cone surface of the rebound guide table into the collection chamber, and the exhaust gas continues to flow along the air flow channel behind the rebound guide cone surface due to the Coanda effect when it flows to the rebound guide cone surface, and finally discharged from the exhaust pipe;

[0024] S5. After the crystal detector detects urea crystals in the collection chamber, it sends a signal to the ECU through the signal transmitter.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The present invention can accumulate urea crystals, and can accurately detect them using only one crystal detector, thereby reducing the detection cost. The crystal concentrator is vibrated by blowing the exhaust gas, and the urea crystals at the attached guide surface are shaken off by the blowing force of the exhaust gas, so that the urea crystals are separated from the attached guide surface. The shaken urea crystals are blown along the attached guide surface by the exhaust gas, and are separated from the exhaust gas at the rebound guide table. The urea crystals rebound into the collection chamber and accumulate, and are more easily detected by the crystal detector, thereby improving the timeliness of detecting urea crystals at the exhaust port. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural block diagram of urea crystal detection according to an embodiment of the present invention;

[0028] Figure 2 A structural cross-sectional view of an embodiment of the present invention;

[0029] Figure 3 A partial structural cross-sectional view of an embodiment of the present invention;

[0030] Figure 4 for Figure 3 A magnified view of the structure at center A;

[0031] Figure 5It is a schematic diagram of the structure of the crystallization concentrator, the rebound guide table and the bracket in the embodiment of the present invention.

[0032] Figure numerals: 1, exhaust pipe; 101, particle collection channel; 102, urea reduction channel; 103, crystallization detection channel; 2, particle collector; 3, urea nozzle; 4, crystallization concentrator; 41, collecting bucket; 411, baffle; 412, collecting plate; 42, extension tube; 43, guide cylinder; 431, collecting chamber; 5, rebound guide platform; 501, air flow channel; 6, bracket; 7, fixing platform a; 8, connecting platform a; 9, heat-resistant rope; 10, connecting platform b; 11, fixing platform b; 12, installation cylinder; 13, photoelectric sensor. DETAILED DESCRIPTION

[0033] Embodiment 1, as Figure 1-Figure 5 As shown, the embodiment proposes an exhaust port urea crystal detection mechanism, which is used to detect urea crystals in an exhaust pipe 1. The exhaust pipe 1 is divided into a particle trapping channel 101, a urea reduction channel 102 and a crystal detection channel 103 which are connected in sequence. A particle trap 2 is arranged in the particle trapping channel 101, and a urea nozzle 3 for spraying urea spray inward is arranged at the urea reduction channel 102. The detection mechanism includes a crystal concentrator 4, a rebound guide table 5, a hanging assembly, a crystal detector and an ECU.

[0034] The crystal concentrator 4 is located inside the exhaust pipe 1, specifically inside the crystal detection channel 103. The crystal concentrator 4 includes a collecting bucket 41, an extension tube 42 and a guide cylinder 43 connected in sequence. The inner surface of the collecting bucket 41 is an attachment guide surface for urea crystals to attach to. The opening size of the extension tube 42 gradually increases in the direction away from the collecting bucket 41, so that the urea crystals can flow to the rebound guide platform 5 after leaving the collecting bucket 41 with the exhaust gas. The guide cylinder 43 has a collecting chamber 431 inside. The collecting chamber 431 is open at one end facing the extension tube 42 and closed at the other end opposite to it. Therefore, urea crystals can enter through the opening of the collecting chamber 431 and will not be discharged from the other closed end.

[0035] like Figure 3 As shown, the hanging assembly is connected between the crystal concentrator 4 and the inner surface of the exhaust pipe 1, and when the exhaust gas blows to the crystal concentrator 4, the crystal concentrator 4 vibrates, and the exhaust gas blows the urea crystals shaken off the crystal concentrator 4 along the attached guide surface.

[0036] like Figure 3-Figure 5As shown, the rebound guide platform 5 is located in the middle of the guide cylinder 43, and an airflow channel 501 is formed between the rebound guide platform 5 and the inner circumference of the guide cylinder 43. The rebound guide platform 5 has a rebound guide conical surface that rebounds the urea crystals blown from the attached guide surface into the collection chamber 431 and guides the exhaust gas flow to the airflow channel 501. The cone top of the rebound guide conical surface faces the direction of the exhaust gas. The urea crystals are rebounded by the rebound guide platform 5 into the collection chamber 431, and the exhaust gas continues to flow along the rebound guide conical surface to the airflow channel 501 and is finally discharged from the end of the exhaust pipe 1. A bracket 6 is connected between the rebound guide platform 5 and the inner circumference of the guide cylinder 43.

[0037] like Figure 4 As shown, the crystal detector is disposed in the collection chamber 431 and detects whether urea crystals are accumulated in the collection chamber 431 by means of photoelectric detection.

[0038] A signal transmitter is communicatively connected between the ECU and the crystallization detector, and the crystallization detector transmits the urea crystallization detection result to the ECU via the signal transmitter.

[0039] The detection method of the exhaust port urea crystal detection mechanism comprises the following steps:

[0040] S1, hoisting the crystal concentrator 4 on the inner side of the exhaust pipe 1 through the hoisting assembly;

[0041] S2, urea crystals are formed at the attachment guide surface of the crystal concentrator 4, and gradually accumulate and increase, and the adhesion of the subsequent accumulated urea crystals decreases;

[0042] S3. When the vehicle is running, the exhaust gas flows in the exhaust pipe 1, and the exhaust gas blows the crystal concentrator 4 to vibrate. The vibration of the crystal concentrator 4 combined with the blowing force of the exhaust gas shakes off the urea crystals that have accumulated and cannot be attached to the attachment guide surface, and blows the shaken off urea crystals backward along the attachment guide surface, and the urea crystals flow backward with the exhaust gas;

[0043] S4, urea crystals are bounced outwards by the rebound guide cone surface of the rebound guide platform 5 into the collection chamber 431, and the exhaust gas continues to flow along the air flow channel 501 behind the rebound guide cone surface due to the Coanda effect when flowing to the rebound guide cone surface, and finally discharged from the exhaust pipe 1;

[0044] S5. After detecting urea crystals in the collecting chamber 431, the crystal detector sends a signal to the ECU via the signal transmitter.

[0045] This embodiment can accumulate urea crystals, and can accurately detect them using only one crystal detector, thereby reducing the detection cost. Before detecting urea crystals, the attachment guide surface of the collecting bucket 41 is used to provide an attachment surface for the formation of urea crystals, and the area of ​​urea crystal formation is increased. The crystal concentrator 4 is blown to vibrate by the exhaust gas, and the urea crystals at the attachment guide surface are shaken off by the blowing force of the exhaust gas, so that the urea crystals are separated from the attachment guide surface. The shaken urea crystals are blown along the attachment guide surface by the exhaust gas, and are in the exhaust gas separation at the rebound guide table 5. The urea crystals rebound into the collection chamber 431 and accumulate, which is easier to be detected by the crystal detector, thereby improving the timeliness of detecting urea crystals at the exhaust port.

[0046] Embodiment 2, as Figure 1-Figure 5 As shown, the present embodiment proposes a urea crystal detection mechanism for an exhaust port. Compared with the first embodiment, in the present embodiment, a plurality of collecting buckets 41 are evenly distributed around the central axis of the crystal concentrator 4, and an exhaust gas channel is formed between two adjacent collecting buckets 41, so as to reduce the resistance to exhaust gas emission, and the exhaust gas can be smoothly discharged backward through the exhaust gas channel. The collecting bucket 41 gradually tilts outward in the direction away from the expansion tube 42, so that the urea spray can be guided, so that the area for urea crystal formation is larger, and the tilted collecting bucket 41 can also guide the urea crystals that fall to flow backward.

[0047] The collecting bucket portion 41 includes a collecting plate portion 412 and two baffle portions 411 respectively connected to both sides of the collecting plate portion 412. The baffle portion 411 faces the inner side of the collecting bucket portion 41. The collecting plate portion 412 is an arc-shaped plate convex outwardly away from the central axis of the crystallization concentrator 4. After being shaken off, the urea crystals can flow more smoothly along the channels between the collecting plate portion 412 and the baffle portions 411 on both sides, making it easier to collect the urea crystals.

[0048] The attachment guide surface is the inner surface of the collecting plate portion 412 , and the attachment guide surface faces the rebound guide conical surface, so that the urea crystals can be blown to the rebound guide conical surface, ensuring that the urea crystals can rebound into the collecting chamber 431 .

[0049] Embodiment three, as Figure 1-Figure 5 As shown, the present embodiment proposes a urea crystal detection mechanism for an exhaust port. Compared with the first embodiment, in the present embodiment, the collecting chamber 431 is an annular chamber, and the axial depth of the collecting chamber 431 gradually increases from top to bottom. The urea crystals rebounded into the collecting chamber 431 from different directions will slide to the bottom of the collecting chamber 431 due to their own gravity, making it easier to collect them in a concentrated manner.

[0050] like Figure 4As shown, the crystal detector includes a mounting tube 12 mounted on the inner bottom of the collecting chamber 431 and a photoelectric sensor 13 disposed in the mounting tube 12 and facing the deepest part of the inner bottom of the collecting chamber 431. In the initial state, the photoelectric sensor 13 detects the distance from the inner bottom of the collecting chamber 431, and sets the rated threshold value of the distance change based on the distance. When urea crystals are subsequently detected, if urea crystals accumulate at the deepest part of the inner bottom of the collecting chamber 431, the distance detected by the photoelectric sensor 13 is shortened. If the shortened distance exceeds the rated threshold range, the ECU determines that there are too many urea crystals and issues an alarm.

[0051] Embodiment 4, as Figure 1-Figure 5 As shown, the present embodiment proposes a urea crystallization detection mechanism for an exhaust port. Compared with the first embodiment, in the present embodiment, the hanging assembly includes three groups of hanging assemblies, two of which are connected between the top of the crystallization concentrator 4 and the top of the inner surface of the exhaust pipe 1 and are arranged side by side. The two groups of hanging assemblies are used to suspend the crystallization concentrator 4 on the inner side of the exhaust pipe 1. When the exhaust gas flows to the crystallization concentrator 4, because the flow rate and direction of the exhaust gas at different times cannot remain completely unchanged, when the exhaust gas continues to flow, the force applied by the exhaust gas to the crystallization concentrator 4 will be different, so that the crystallization concentrator 4 can be blown and shaken, so that the crystallization concentrator 4 vibrates under the suspension of the two groups of hanging assemblies. Another group of hanging assemblies is connected between the bottom of the crystallization concentrator 4 and the bottom of the inner surface of the exhaust pipe 1. The other group of hanging assemblies is used to limit the vibration amplitude of the crystallization concentrator 4 to prevent the crystallization concentrator 4 from hitting the inner wall of the exhaust pipe 1 due to excessive vibration amplitude. The lifting assembly includes a fixed table a7 connected to the inner surface of the exhaust pipe 1, a connecting table a8 connected to the fixed table a7, a fixed table b11 connected to the outer surface of the crystallization concentrator 4, a connecting table b10 connected to the fixed table b11, and a heat-resistant rope 9 connected between the connecting table a8 and the connecting table b10. The heat-resistant rope 9 is a rope that can be used under the temperature environment at the end of the exhaust pipe 1.

[0052] like Figure 3 As shown, the heat-resistant rope 9 in the hanging assembly above the crystal concentrator 4 is in a tensioned state. Due to the gravity of the crystal concentrator 4, the heat-resistant rope 9 is tensioned, but it still shakes under the blowing force of the exhaust gas. The heat-resistant rope 9 in the hanging assembly below the crystal concentrator 4 is in a loose state, ensuring that the crystal concentrator 4 has a certain range of movement, but does not collide with the inner wall of the exhaust pipe 1.

[0053] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. An exhaust port urea crystal detection mechanism, used for detecting urea crystals in an exhaust pipe (1), characterized in that: include: A crystal concentrator (4) is located inside the exhaust pipe (1), and comprises a collecting bucket (41), an extension tube (42), and a guide tube (43) connected in sequence, wherein the inner surface of the collecting bucket (41) is an attachment guide surface for urea crystals to attach to, the opening size of the extension tube (42) gradually increases in a direction away from the collecting bucket (41), and the inner side of the guide tube (43) comprises a collecting chamber (431), wherein one end of the collecting chamber (431) facing the extension tube (42) is open and the other end opposite to the collection chamber (431) is closed; a hanging assembly connected between the crystal concentrator (4) and the inner surface of the exhaust pipe (1), and causing the crystal concentrator (4) to vibrate when the exhaust gas is blown to the crystal concentrator (4), so that the exhaust gas blows the urea crystals shaken off the crystal concentrator (4) along the attached guide surface; A rebound guide platform (5), which is located in the middle of the guide cylinder (43) and forms an airflow channel (501) with the inner circumferential surface of the guide cylinder (43), and has a rebound guide conical surface for rebounding urea crystals blown from the attached guide surface into the collection chamber (431) and guiding the exhaust gas flow toward the airflow channel (501); A crystal detector, which is arranged in the collection chamber (431) and detects whether urea crystals are accumulated in the collection chamber (431) by means of photoelectric detection; The ECU is communicatively connected with the crystallization detector via a signal transmitter.

2. The exhaust port urea crystal detection mechanism according to claim 1, characterized in that: A plurality of collecting buckets (41) are evenly distributed around the central axis of the crystallization concentrator (4), an exhaust gas channel is formed between two adjacent collecting buckets (41), and the collecting buckets (41) gradually tilt outward in a direction away from the expansion tube (42).

3. The exhaust port urea crystal detection mechanism according to claim 2, characterized in that: The collecting hopper portion (41) comprises a collecting plate portion (412) and two baffle portions (411) respectively connected to both sides of the collecting plate portion (412), wherein the baffle portions (411) face the inside of the collecting hopper portion (41).

4. The exhaust port urea crystal detection mechanism according to claim 3, characterized in that: The collecting plate portion (412) is an arc-shaped plate that bulges outward in a direction away from the central axis of the crystallization concentrator (4).

5. The exhaust port urea crystal detection mechanism according to claim 4, characterized in that: The attachment guide surface is the inner surface of the collection plate portion (412), and the attachment guide surface faces the rebound guide conical surface.

6. The exhaust port urea crystal detection mechanism according to claim 1, characterized in that: The collecting chamber (431) is an annular chamber, and the axial depth of the collecting chamber (431) gradually increases from top to bottom.

7. The exhaust port urea crystal detection mechanism according to claim 6, characterized in that: The crystallization detector comprises a mounting tube (12) mounted on the inner bottom of the collection chamber (431), and a photoelectric sensor (13) arranged in the mounting tube (12) and facing the deepest part of the inner bottom of the collection chamber (431).

8. The exhaust port urea crystal detection mechanism according to claim 1, characterized in that: A bracket (6) for mounting the rebound guide platform (5) is provided on the inner circumferential surface of the guide cylinder portion (43).

9. The exhaust port urea crystal detection mechanism according to claim 1, characterized in that: The hanging assembly comprises three groups of hanging assemblies, two groups of hanging assemblies are connected between the top of the crystallization concentrator (4) and the top of the inner surface of the exhaust pipe (1) and are arranged side by side, and the other group of hanging assemblies is connected between the bottom of the crystallization concentrator (4) and the bottom of the inner surface of the exhaust pipe (1); the hanging assemblies comprise a fixed platform a (7) connected to the inner surface of the exhaust pipe (1), a connecting platform a (8) connected to the fixed platform a (7), a fixed platform b (11) connected to the outer surface of the crystallization concentrator (4), a connecting platform b (10) connected to the fixed platform b (11), and a heat-resistant rope (9) connected between the connecting platform a (8) and the connecting platform b (10); the heat-resistant rope (9) in the hanging assembly located above the crystallization concentrator (4) is in a tensioned state, and the heat-resistant rope (9) in the hanging assembly located below the crystallization concentrator (4) is in a loose state.

10. A method for detecting urea crystals at exhaust ports according to claim 1, characterized in that: The steps include: S1, hoisting the crystallization concentrator (4) on the inner side of the exhaust pipe (1) by means of a hoisting assembly; S2, urea crystals are formed on the attached guide surface of the crystal concentrator (4), and gradually accumulate and increase; S3, when the vehicle is running, the exhaust gas flows in the exhaust pipe (1), and the exhaust gas blows the crystal concentrator (4) to vibrate. The vibration of the crystal concentrator (4) and the blowing force of the exhaust gas shake off the urea crystals that have accumulated and cannot be attached to the attachment guide surface, and the shaken off urea crystals are blown backward along the attachment guide surface, and the urea crystals flow backward along the exhaust gas; S4, urea crystals are bounced outwards by the rebound guide cone surface of the rebound guide platform (5) into the collection chamber (431), and the exhaust gas continues to flow along the air flow channel (501) behind the rebound guide cone surface due to the Coanda effect when flowing to the rebound guide cone surface, and finally discharged from the exhaust pipe (1); S5. After the crystal detector detects urea crystals in the collecting chamber (431), it sends a signal to the ECU via the signal transmitter.

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