Integrated SCR mixer structure and control method

Abstract

The invention discloses an integrated SCR mixer structure and a control method.The integrated SCR mixer structure comprises an ECU integrated device, a rotary mixing device and an SCR postprocessor, and the ECU integrated device is electrically connected with a temperature sensor and a urea concentration sensor; the rotary mixing device comprises a metal blade wheel, a heating pipe, a backflow butt joint pipe, a driving impeller and an inductance heating ring, the wall of an exhaust pipeline of the vehicle is provided with a first annular cavity located on the outermost layer and a second annular cavity located on the inner layer of the first annular cavity, the inductance heating ring is arranged in the first annular cavity, and the heating pipe and the backflow butt joint pipe are arranged in the second annular cavity in an end-to-end butt joint mode. The heating pipe is made of metal and filled with evaporated liquor, an injection valve is arranged at the top end of the heating pipe, the driving impeller is arranged above the injection valve, an outer rim of the metal blade wheel is matched with a bearing of the wall of the exhaust pipeline, the blades are made of metal, and a transmission assembly is installed in the second annular cavity. The transmission assembly is in transmission fit with the outer wheel ring of the metal blade wheel and the driving impeller.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel engine after-treatment, and particularly to an integrated SCR mixer structure and a control method thereof. Background Art

[0002] The Selective Catalytic Reduction (SCR) system is an effective technical means to reduce NOx under the National VI regulations. Installing a mixer before the SCR can improve the conversion efficiency of NOx. By optimizing the structure of the mixer, the uniformity of NH3 distribution can be improved, and further the conversion efficiency of the SCR system can be enhanced.

[0003] Although the existing SCR systems are equipped with mixer structures, during the WHTC test cycle or operation in a low-temperature environment, the proportion of low-speed and low-load conditions increases, and the exhaust temperature is relatively low. A large number of side reactions occur during the decomposition process of the urea aqueous solution, and polymers such as melamine are easily generated, which affects the conversion efficiency of NOx. In addition, when the exhaust temperature is low, the atomization effect of the urea aqueous solution becomes poor, and deposits are easily formed on the exhaust pipe wall and the catalyst carrier, blocking the catalyst pores, resulting in a reduction in the amount of ammonia generated, a decrease in the conversion efficiency of NOx, and an increase in the exhaust back pressure, which may even lead to a decline in the engine economy and a decrease in power performance. Summary of the Invention

[0004] In order to solve the problems mentioned in the above background art, the present invention provides an integrated SCR mixer structure and a control method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An integrated SCR mixer structure includes an ECU integrated device, a rotary mixing device, and an SCR post-processor. The ECU integrated device is electrically connected to a temperature sensor and a urea concentration sensor. The rotary mixing device includes a metal blade wheel, a heating pipe, a reflux docking pipe, a driving impeller, and an inductive heating coil. The exhaust pipe wall of the vehicle has a first annular cavity in the outermost layer and a second annular cavity in the inner layer of the first annular cavity. The inductive heating coil is arranged in the first annular cavity. The heating pipe and the reflux docking pipe are arranged end to end in the second annular cavity. The heating pipe is made of metal, and an evaporation liquid is filled in the heating pipe. A spray valve is arranged at the top of the heating pipe, and the driving impeller is arranged above the spray valve.

[0007] The outer rim of the metal blade wheel is in bearing fit with the exhaust pipe wall. The blades are made of metal. A transmission component is installed in the second annular cavity, and the transmission component is in transmission cooperation with the outer rim of the metal blade wheel and the driving impeller.

[0008] Preferably, the part of the exhaust pipe wall sleeved by the inductive heating coil is made of heat-resistant ceramics. The balls used for the bearing fit between the metal blade wheel and the exhaust pipe wall are also ceramic balls. The reflux docking pipe is made of heat-resistant plastic or ceramics.

[0009] Preferably, the ECU integrated device is powered by the vehicle power supply. An Observer detector is provided inside the ECU integrated device to monitor the temperature of the rotary mixing device in real time and control the temperature of the rotary mixing device to be maintained within the optimal range in real time according to the PID (Proportional-Integral-Derivative) correction control algorithm operated by the Observer detector. After being mixed and heated by the rotary mixing device, the engine exhaust gas enters the SCR post-processor for further processing.

[0010] Preferably, the transmission assembly includes a driving disk, a driven disk, a through shaft, and a helical gear disk. The driven disk and the helical gear disk are respectively installed at both ends of the through shaft. Helical teeth matching with the helical gear disk are arranged in a circular pattern on the rim of the metal blade wheel.

[0011] Preferably, the through shaft passes through the second annular cavity and the helical gear disk is arranged in a space separately opened on the exhaust pipe wall. In this space, the helical gear disk is in gear engagement with the metal blade wheel. The driving disk is coaxially installed on the driving impeller, and the driving disk and the driven disk are driven by a transmission belt to rotate synchronously.

[0012] Preferably, the upper end of the reflux docking pipe is open and communicates with the space in the second annular cavity where the vapor is injected. A part of the vapor injected into the second annular cavity is cooled and liquefied in the second annular cavity and then flows back to the partition block provided by the injection valve. After being collected by the partition block, it is guided to the reflux docking pipe by the reflux pipe.

[0013] Preferably, the connection part between the reflux docking pipe and the heating pipe has a communication port. A buoyancy control member is provided inside the heating pipe to control the opening and closing of the reflux docking pipe and the heating pipe. The buoyancy control member includes a floating ball, a pulling rope, and a sealing plug. The floating ball and the sealing plug are installed on the pulling rope. The pulling rope passes through the communication port so that the floating ball immersed in the evaporation liquid of the heating pipe can pull up the sealing plug under the action of buoyancy to block the communication port.

[0014] An integrated SCR mixer control method includes the following steps:

[0015] S1: The temperature sensor first detects the discharge temperature of the vehicle exhaust gas. At the same time, the ECU integrated device 1 controls the urea nozzle to spray urea spray into the exhaust pipe.

[0016] S2: The ECU integrated device controls the operation of the inductive heating coil according to the temperature monitored by the temperature sensor 4 and the temperature of the rotary mixing device monitored by the Observer detector, so that the rotation speed and temperature of the metal blade wheel are in the optimal state.

[0017] S3: The tail gas that is fully mixed with urea spray and heated by the rotary mixing device is discharged after being processed by the SCR post-processor.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] When the engine is undergoing cyclic testing or operating in a low-temperature environment, through the vane structure of the present invention, NH3 generated from urea can be fully mixed with the exhaust gas, and the temperature of the tail gas can also be increased by heating, thereby improving the NOx conversion efficiency and effectively avoiding the occurrence of urea crystallization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of an integrated SCR mixer structure according to the present invention;

[0022] Figure 2 It is a front structural schematic diagram of the rotary mixing device according to the present invention;

[0023] Figure 3 It is a back structural schematic diagram of the rotary mixing device according to the present invention;

[0024] Figure 4 It is a schematic structural diagram of the buoyancy control member according to the present invention.

[0025] In the figure: 1. ECU integrated device; 2. Rotary mixing device; 201. First annular cavity; 202. Second annular cavity; 21. Metal vane wheel; 22. Heating pipe; 23. Return connection pipe; 24. Driving impeller; 25. Inductive heating coil; 26. Injection valve; 27. Transmission assembly; 271. Driving disk; 272. Driven disk; 273. Through shaft; 274. Helical gear disk; 275. Transmission belt; 28. Return pipe; 29. Buoyancy control member; 291. Floating ball; 292. Pulling rope; 293. Sealing plug; 3. SCR post-processor; 4. Temperature sensor; 5. Urea concentration sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Embodiment 1

[0028] Referring to Figures 1-4 , an integrated SCR mixer structure includes an ECU integrated device 1, a rotary mixing device 2, and an SCR post-processor 3. The ECU integrated device 1 is electrically connected to a temperature sensor 4 and a urea concentration sensor 5, and controls the urea nozzle before the rotary mixing device 2. The operation is powered by the vehicle power supply. An Observer detector is provided in the ECU integrated device 1 to monitor the temperature of the rotary mixing device 2 in real time and control the temperature of the rotary mixing device 2 to be maintained within the optimal range in real time according to the PID (Proportional-Integral-Derivative) correction control algorithm run by the Observer detector. The engine exhaust gas enters the SCR post-processor 3 for further processing after being mixed and heated by the rotary mixing device 2.

[0029] The rotary mixing device 2 includes a metal blade wheel 21, a heating pipe 22, a reflux docking pipe 23, a drive impeller 24, and an inductive heating coil 25. The exhaust pipe wall of the vehicle has a first annular cavity 201 in the outermost layer and a second annular cavity 202 in the inner layer of the first annular cavity 201. The inductive heating coil 25 is arranged in the first annular cavity 201, and the magnetic field generated after passing an alternating current can heat the metal components inside the annular channel. The heating pipe 22 and the reflux docking pipe 23 are arranged end to end in the second annular cavity 202. An evaporation liquid is filled in the heating pipe 22. A spray valve 26 is provided at the top of the heating pipe 22. The heating pipe 22 is made of metal and can be inductively heated, so that the evaporation liquid filled inside is heated and vaporized. After the evaporation liquid that has vaporized and evaporated reaches the preset pressure for the spray valve 26 to relieve pressure, it will be sprayed out at high speed by the spray valve 26. The drive impeller 24 is arranged above the spray valve 26. The high-speed and high-pressure gas sprayed out by the spray valve 26 can push the drive impeller 24 to rotate axially.

[0030] The outer rim of the metal vane wheel 21 is in bearing fit with the exhaust pipe wall. The part of the exhaust pipe wall sleeved by the inductive heating coil 25 is made of heat-resistant ceramics, so that it will not be electrified and heated up after the inductive heating coil 25 is energized, and can dissipate the heat of the vaporized liquid vapor sprayed into the second annular cavity 202, so that the vapor can be recooled and liquefied after entering the second annular cavity 202. The balls used for the bearing fit between the metal vane wheel 21 and the exhaust pipe wall are also ceramic balls. When the vehicle engine runs at high speed, when a large amount of exhaust gas passes through the arc-shaped structure of the vanes of the metal vane wheel 21, the vanes will obtain power from the kinetic energy of the exhaust gas and rotate. At the same time, the urea sprayed by the urea nozzle will be preliminarily mixed with the exhaust gas. Due to the large kinetic energy of the exhaust gas, local aggregation will occur after the urea is impacted, resulting in insufficient reaction and crystallization. When the mixed gas passes through the vanes, due to the stirring and mixing effect of the vanes, the locally aggregated mixed gas will be dispersed and then fully mixed. The rotation of the vane structure not only promotes the full mixing of the urea droplets and the exhaust gas flow, but also enhances the atomization effect of the urea, making the mixing of the engine exhaust gas and NH3 generated by the decomposition of urea more sufficient.

[0031] When starting cold or under light load conditions, the kinetic energy of the exhaust gas is low, the vane speed is low, and the mixing effect is poor, and the conversion efficiency of NOx is also low. At this time, the vehicle energizes the inductive heating coil 25 to heat the metal vanes of the metal vane wheel 21. At the same time, the vaporized liquid evaporated in the heating pipe 22 is ejected by the injection valve 26 to drive the drive impeller 24 to rotate. A transmission assembly 27 is installed in the second annular cavity 202. The transmission assembly 27 includes a drive disk 271, a driven disk 272, a through shaft 273, and a helical disk 274. The driven disk 272 and the helical disk 274 are respectively installed at both ends of the through shaft 273. Helical teeth matching with the helical disk 274 are arranged in a circular pattern on the rim of the metal vane wheel 21. The through shaft 273 passes through the second annular cavity 202 to arrange the helical disk 274 in a space separately opened on the exhaust pipe wall. In this space, the helical disk 274 is in gear fit with the metal vane wheel 21. The drive disk 271 is coaxially installed on the drive impeller 24, and the drive disk 271 and the driven disk 272 are driven by a transmission belt 275 to rotate synchronously.

[0032] Under cold start or light load conditions of the vehicle, by energizing the inductive heating coil 25 to heat the metal vane wheel 21 and the vaporized liquid in the heating pipe 22, after the drive impeller 24 is driven to rotate by the vapor, it can apply rotational power to the metal vane wheel 21 through the transmission of the transmission assembly 27, so that the engine exhaust gas and urea can always be mixed evenly at an appropriate temperature, ensuring the exhaust gas treatment effect.

[0033] Embodiment 2

[0034] Refer to Figures 1-4, The difference between this embodiment and Embodiment 1 is that the upper end of the reflux docking pipe 23 is open and communicates with the space in the second annular cavity 202 into which the vapor is injected. A part of the vapor injected into the second annular cavity 202 is cooled and liquefied in the second annular cavity 202 and then flows back to the partition block provided in the injection valve 26. After being collected by the partition block, it is guided by the reflux pipe 28 to the reflux docking pipe 23. At the same time, the vapor that spreads to the upper part of the second annular cavity 202 and is not cooled and liquefied will be received and guided by the reflux docking pipe 23, and finally liquefies and accumulates at the bottom of the reflux docking pipe 23. The reflux docking pipe 23 is made of heat-resistant plastic or ceramic material, so it will not generate heat inductively.

[0035] There is a communication port at the docking part of the reflux docking pipe 23 and the heating pipe 22. A buoyancy control member 29 is arranged in the heating pipe 22 to control the opening and closing of the reflux docking pipe 23 and the heating pipe 22. The buoyancy control member 29 includes a floating ball 291, a pull rope 292 and a sealing plug 293. The floating ball 291 and the sealing plug 293 are installed on the pull rope 292. The pull rope 292 passes through the communication port so that the floating ball 291 immersed in the evaporation liquid in the heating pipe 22 can pull up the sealing plug 293 under the action of buoyancy to block the communication port. After the evaporation liquid in the heating pipe 22 continuously evaporates and the liquid level drops, the floating ball 291 moves down with the evaporation liquid level and cannot provide enough upward pulling force for the sealing plug 293. At this time, the sealing plug 293 moves down under the action of gravity to open the communication port, so that the cooled evaporation liquid collected at the bottom of the reflux docking pipe 23 is supplemented into the heating pipe 22 for continuous heating and generating vapor.

[0036] Embodiment 3

[0037] An integrated SCR mixer control method includes the following steps:

[0038] S1: The temperature sensor 4 first detects the exhaust temperature of the vehicle exhaust, and at the same time the ECU integrated device 1 controls the urea nozzle to spray urea spray into the exhaust pipe;

[0039] S2: The ECU integrated device 1 controls the operation of the inductive heating coil 25 according to the temperature monitored by the temperature sensor 4 and the temperature of the rotary mixing device 2 monitored by the Observer detector, so that the rotation speed and temperature of the metal blade wheel 21 are in the best state;

[0040] S3: The exhaust gas that is fully mixed with the urea spray and heated by the rotary mixing device 2 is discharged after being processed by the SCR post-processor 3.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is 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. Therefore, it should not be construed as a limitation to the present invention.

[0042] In the present invention, unless otherwise clearly defined and limited, the terms "set", "install", "connect", "couple", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. It can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] The control mode of the present invention is automatically controlled by a controller. The control circuit of the controller can be realized by simple programming by those skilled in the art. The provision of power also belongs to the common general knowledge in the art. And the present invention is mainly used to protect mechanical devices. Therefore, the control mode and circuit connection of the present invention will not be explained in detail.

[0044] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. An integrated SCR mixer structure, comprising an ECU integrated device (1), a rotary mixing device (2) and an SCR post-processor (3). The ECU integrated device (1) is electrically connected to a temperature sensor (4) and a urea concentration sensor (5), and is characterized in that: The rotary mixing device (2) includes a metal blade wheel (21), a heating pipe (22), a reflux docking pipe (23), a driving impeller (24) and an inductive heating coil (25). The exhaust pipe wall of the vehicle has a first annular cavity (201) at the outermost layer, and a second annular cavity (202) inside the first annular cavity (201). The inductive heating coil (25) is arranged in the first annular cavity (201). The heating pipe (22) and the reflux docking pipe (23) are arranged end to end in the second annular cavity (202). The heating pipe (22) is made of metal, and an evaporation liquid is filled in the heating pipe (22). A spray valve (26) is arranged at the top of the heating pipe (22), and the driving impeller (24) is arranged above the spray valve (26); The outer rim of the metal blade wheel (21) is in bearing fit with the exhaust pipe wall, and the blades are made of metal. A transmission assembly (27) is installed in the second annular cavity (202), and the transmission assembly (27) is in transmission fit with the outer rim of the metal blade wheel (21) and the driving impeller (24).

2. The integrated SCR mixer structure according to claim 1, characterized in that: The part of the exhaust pipe wall sleeved by the inductive heating coil (25) is made of heat-resistant ceramic. The balls used for the bearing fit between the metal blade wheel (21) and the exhaust pipe wall are also ceramic balls. The reflux docking pipe (23) is made of heat-resistant plastic or ceramic material.

3. An integrated SCR mixer structure according to claim 1, characterized in that: The ECU integrated device (1) is powered by the vehicle power supply. An Observer detector is arranged in the ECU integrated device (1) to monitor the temperature of the rotary mixing device (2) in real time, and the temperature of the rotary mixing device (2) is controlled in real time according to the PID correction control algorithm operated by the Observer detector to be kept within the optimal range. The engine exhaust gas enters the SCR post-processor (3) for further processing after being mixed and heated by the rotary mixing device (2).

4. An integrated SCR mixer structure according to claim 1, characterized in that: The transmission assembly (27) includes a driving disk (271), a driven disk (272), a through shaft (273) and a helical disk (274). The driven disk (272) and the helical disk (274) are respectively installed at both ends of the through shaft (273). Helical teeth matching with the helical disk (274) are arranged in a circular arrangement on the rim of the metal blade wheel (21).

5. An integrated SCR mixer structure according to claim 4, characterized in that: The through shaft (273) penetrates out of the second annular cavity (202) to arrange the helical disk (274) in a space separately opened on the exhaust pipe wall. In this space, the helical disk (274) is in gear fit with the metal blade wheel (21). The driving disk (271) is coaxially installed on the driving impeller (24), and the driving disk (271) and the driven disk (272) are in transmission through a transmission belt (275) and can rotate synchronously.

6. An integrated SCR mixer structure according to claim 1, characterized in that: The upper end of the reflux connection pipe (23) is open and communicates with the space in the second annular cavity (202) into which the vapor is injected. A part of the vapor injected into the second annular cavity (202) is cooled and liquefied in the second annular cavity (202), then flows back to the partition block provided in the injection valve (26), and is collected by the partition block and guided to the reflux connection pipe (23) by the reflux pipe (28).

7. An integrated SCR mixer structure according to claim 6, characterized in that: The connection part between the reflux connection pipe (23) and the heating pipe (22) has a communication port. A buoyancy control member (29) is arranged in the heating pipe (22) to control the opening and closing of the reflux connection pipe (23) and the heating pipe (22). The buoyancy control member (29) includes a floating ball (291), a pulling rope (292) and a plug (293). The floating ball (291) and the plug (293) are installed on the pulling rope (292). The pulling rope (292) passes through the communication port, so that the floating ball (291) immersed in the evaporation liquid in the heating pipe (22) can pull up the plug (293) under the action of buoyancy to block the communication port.

8. An integrated SCR mixer control method, using the integrated SCR mixer structure according to any one of claims 1-7, characterized in that, Including the following steps: S1: The temperature sensor (4) first detects the exhaust temperature of the vehicle exhaust. At the same time, the ECU integrated device (1) controls the urea nozzle to spray urea into the exhaust pipe. S2: The ECU integrated device (1) controls the operation of the inductive heating coil (25) according to the temperature monitored by the temperature sensor (4) and the temperature of the rotary mixing device (2) monitored by the Observer detector, so that the rotation speed and temperature of the metal blade wheel (21) are in the best state. S3: The exhaust gas that is fully mixed with the urea spray and heated by the rotary mixing device (2) is discharged after being processed by the SCR post-processor (3).

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