A catalytic reactor for a diesel engine

Abstract

The utility model discloses a kind of catalytic reactors for diesel engine, including DOC reactor, DPF filter and SCR reactor sequentially arranged according to exhaust flow direction intercommunication, DOC reactor is integrated into cylinder unit structure with DPF filter, and communication installation is arranged between SCR reactor cyclone mixer and urea mixing pipe;The upstream end of DOC reactor is equipped with exhaust gas inlet, and exhaust gas outlet is arranged at the downstream end of SCR reactor.Catalytic reactor is equipped with two urea nozzle seats and the corresponding sensor seat matched therewith.The utility model adds a urea nozzle seat and the corresponding multiple sensor seats on the basis of original vehicle, uses the signal of newly added sensor detection as input, more accurately detects exhaust emission parameter, and then controls urea injection to treat tail gas, improves conversion efficiency, so that vehicle is upgraded from guo five emission to reach guo six emission standard.

Description

Technical Field

[0001] This utility model relates to the field of diesel engine exhaust purification technology, specifically to a catalytic reactor for diesel engines. Background Technology

[0002] The main harmful emissions from diesel engines are CO, HC, PM and NOx. CO and HC emissions are usually relatively low and easy to treat; PM and NOx emissions are relatively high and are the two main emissions from diesel engines. PM is usually treated with a particulate filter (DPF), while NOx emissions are treated with selective catalytic reduction (SCR) technology.

[0003] For heavy-duty diesel engines, the China IV emission standard typically uses high-pressure common rail + SCR technology to meet emission standards. The China V standard maintains the same overall technical approach, still employing high-pressure common rail + SCR technology, but requires further optimization of engine data and SCR reactor configuration to improve SCR efficiency. Upgrading from China V to China VI is a systematic project, requiring the coordinated development of the engine itself and exhaust aftertreatment technology to meet emission, OBD, and durability / reliability requirements.

[0004] With the upgrading of emission regulations, a large number of vehicles in use that meet the China V emission standard have higher emissions than those meeting the China VI standard. For some key environmental governance cities, such as the 26 key environmental governance cities around the Beijing-Tianjin area proposed by the environmental protection department, there is a demand for emission retrofitting and upgrading of vehicles that meet the China IV and China V standards. The goal is to enable vehicles to meet the China VI emission standards on the basis of their original performance. However, the processing capacity of the existing emission treatment systems for vehicles cannot achieve this, and further upgrades are needed. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of the existing technology and provide a catalytic reactor for diesel engines.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a catalytic reactor for a diesel engine, comprising a DOC reactor, a DPF filter, and an SCR reactor arranged and connected in sequence according to the exhaust gas flow direction, wherein the DOC reactor and the DPF filter are integrated into a cylindrical unit structure, and a swirl mixer and a urea mixing pipe are installed between the DOC reactor and the SCR reactor; an exhaust gas inlet is provided at the upstream end of the DOC reactor, and an exhaust gas outlet is provided at the downstream end of the SCR reactor; the catalytic reactor is provided with two urea nozzle seats and corresponding sensor seats.

[0007] By adding a new urea injection mounting assembly to the existing vehicle, which consists of two urea nozzle seats, each with a corresponding urea spray gun or urea nozzle, the amount of urea injected is increased, thereby improving the catalytic reduction efficiency.

[0008] Furthermore, the two urea injection seats are the original urea nozzle seat and the supplementary urea nozzle seat, respectively. The original urea nozzle seat is located at the inlet position of the aforementioned cyclone mixer, and the supplementary urea nozzle seat is located on the SCR mixing chamber. The two urea nozzle seats are on the same cross section, and their central axes are at 90° to each other.

[0009] Furthermore, the original sensor seat corresponding to the original urea nozzle seat includes an exhaust temperature sensor seat T1, a NOx sensor seat N3, and an exhaust temperature sensor seat T4, wherein the exhaust temperature sensor seat T1 is located at the rear end of the aforementioned DPF filter, and the NOx sensor seat N3 and the exhaust temperature sensor seat T4 are located in the exhaust gas outlet area.

[0010] Furthermore, the supplementary spray sensor seat corresponding to the supplementary urea nozzle seat includes a NOx sensor seat N1, an exhaust temperature sensor seat T2, a NOx sensor seat N2, an exhaust temperature sensor seat T3, a front differential pressure sensor seat, and a rear differential pressure sensor seat. The NOx sensor seat N1 is disposed on the front wall of the aforementioned DOC reactor, the exhaust temperature sensor seat T2 is disposed on the rear end of the aforementioned DPF filter, and the NOx sensor seat N2 and the exhaust temperature sensor seat T3 are disposed on the rear end of the aforementioned SCR reactor. The aforementioned front differential pressure sensor seat and the rear differential pressure sensor seat are respectively disposed on the front and rear side walls of the aforementioned DOC reactor.

[0011] Furthermore, the DOC reactor, DPF filter, and SCR reactor are arranged in a U-shaped structure.

[0012] Furthermore, the DOC reactor and the DPF filter are connected by clamps; the cyclone mixer and the urea mixing pipe are fixed by flanges.

[0013] Furthermore, the corresponding sensors can be detachably installed in different sensor holders and sealed.

[0014] Compared with the prior art, this utility model has the following beneficial effects: This utility model adds a urea nozzle seat to the original vehicle and correspondingly adds a urea injection signal detection system. The mounting seats of each corresponding sensor are designed in appropriate positions to facilitate the installation of each sensor. By using the detection signal of the newly added sensor as input, the exhaust emission parameters are detected more accurately, thereby controlling the urea injection to treat the exhaust gas, improving the conversion efficiency, and enabling the vehicle to be upgraded from the National V emission standard to the National VI emission standard, which is effective. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 Longitudinal center section view of the structure; In the diagram: 1. Exhaust gas inlet, 2. Front differential pressure sensor holder, 3. Rear differential pressure sensor holder, 4. Exhaust temperature sensor holder T1, 5. NOx sensor holder N1, 6. DOC reactor, 7. DPF filter, 8. Exhaust temperature sensor holder T2, 9. SCR mixing chamber, 10. Original urea nozzle holder, 11. Supplementary urea nozzle holder, 12. Swirl mixer, 13. Urea mixing pipe, 14. SCR reactor, 15. NOx sensor holder N2, 16. NOx sensor holder N3, 17. Exhaust temperature sensor holder T3, 18. Exhaust temperature sensor holder T4. Detailed Implementation

[0016] It should be noted that in the description of this utility model, terms such as "upper", "lower", "front", "rear", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the structural relationship of each component in this utility model and do not specifically mean that any component in this utility model must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as a limitation on this utility model.

[0017] Furthermore, in utility models, descriptions such as "first" and "second" are for descriptive purposes only and do not specifically refer to any order or sequence, nor are they intended to limit the utility model. They are merely used to distinguish components or operations described with the same technical terms and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0018] Secondly, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0019] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings (with the direction of waste gas flow as the front): like Figure 1As shown, a catalytic reactor for diesel engines is an improvement on the existing device in vehicles meeting China IV or China V emission standards. It adds a relatively independent urea injection device. Specifically, the catalytic reactor includes a DOC reactor 6, a DPF filter 7, and an SCR reactor 14 arranged sequentially and connected according to the exhaust gas flow direction. The DOC reactor 6 and DPF filter 7 are fixed together by clamps, forming a cylindrical unit. An SCR mixing chamber 9 is connected and installed behind the DPF filter 7, and the two are also fixed together by clamps. A cyclone mixer 12 is installed inside the SCR mixing chamber 9, and its output end is connected to a urea mixing pipe 13 via a flange. The urea mixing pipe 13 extends into and is installed at the front end of the SCR reactor 14.

[0020] The aforementioned DOC reactor 6 has an exhaust gas inlet 1 on its front cylindrical wall, which serves as the starting point for gas entry into the entire equipment and marks the beginning of the gas flow. The front cylindrical wall of the DOC reactor 6 is equipped with a front differential pressure sensor seat 2 and a NOx sensor seat N1 5, both located above the exhaust gas inlet 1. A first NOx sensor is detachably inserted into the NOx sensor seat N1 5. The rear cylindrical wall of the DOC reactor 6 is equipped with a rear differential pressure sensor seat 3, arranged in the same row as the front differential pressure sensor seat 2. Both work together to install a differential pressure sensor, enabling real-time detection of the pressure difference between the front and rear ends of the DOC reactor 6. Because the DOC reactor 6 has a permeable opening connecting the front and rear ends, preventing blockage, the pressure difference caused by varying exhaust gas volumes reflects different operating conditions, outputting key signals to control the urea injection rate. The rear end of the DPF filter 7 and the cavity wall of the SCR mixing chamber 9 are provided with exhaust temperature sensor seat T1 4 and exhaust temperature sensor seat T28, respectively, and corresponding exhaust temperature sensors are inserted inside them. Among them, exhaust temperature sensor seat T1 4 belongs to the original vehicle urea injection sensor seat.

[0021] The SCR mixing chamber 9 has two urea nozzle seats on its wall: a primary urea nozzle seat 10 and a supplementary urea nozzle seat 11. The primary urea nozzle seat 10 is located to the upper right of the exhaust temperature sensor seat T2 8, at the inlet end of the swirl mixer 12, and houses the original vehicle urea nozzle to ensure the integrity of the original vehicle system (otherwise, the original vehicle would not function). The supplementary urea nozzle seat 11 is located at an appropriate position in the SCR mixing chamber 9, in front of the connection between the swirl mixer 12 and the urea mixing pipe 13, and houses a supplementary urea nozzle for supplementing the urea injection volume, thereby achieving higher NOx conversion efficiency. The primary urea nozzle seat 10 and the supplementary urea nozzle seat 11 are on the same cross-section, and their central axes are set at a 90° angle to each other.

[0022] The SCR reactor 14 has an exhaust gas outlet at its rear end. Simultaneously, the rear cylindrical wall of the SCR reactor 14 is equipped with a NOx sensor holder N2 15 and an exhaust temperature sensor holder T3 17, which can respectively accommodate a second NOx sensor and a third exhaust temperature sensor. The NOx sensor holder N2 15 and exhaust temperature sensor holder T3 17 are urea injection sensor holders for supplementary urea injection. A NOx sensor holder N3 16 and an exhaust temperature sensor holder T4 18 are provided on the cavity wall in the exhaust gas outlet area. These are original vehicle urea injection sensor holders, and their interiors accommodate a third NOx sensor and a fourth exhaust temperature sensor to ensure the normal operation of the original vehicle.

[0023] The further optimized technical solution is that the above-mentioned integrated cylindrical DOC reactor 6, DPF filter 7 and SCR reactor 14 are installed in a U-shaped structure, which can better take into account emission and space characteristics. Compared with the traditional box-type after-treatment device, it has good advantages in vehicle application and can be assembled vertically, horizontally or inclined according to the actual installation space.

[0024] The aforementioned differential pressure sensor, first NOx sensor, second exhaust temperature sensor, and third exhaust temperature sensor are all connected to the controller and belong to the newly added urea injection control system. The aforementioned first exhaust temperature sensor, third NOx sensor, and fourth exhaust temperature sensor are also connected to the controller and belong to the original urea injection control system. The urea injection control system is relatively independent of the original urea injection control system; the sensors installed within them cannot be shared to avoid electrical signal interference and to prevent affecting the normal operation of the original vehicle. The controller is connected to the urea injection pump, which is connected to the corresponding urea nozzle through the urea injection pipe. The frequency of urea injection is then controlled by monitoring data from the added sensors.

[0025] Of course, the above description is not intended to limit the present utility model, and the present utility model is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present utility model should also fall within the protection scope of the present utility model.

Claims

1. A catalytic reactor for a diesel engine, characterized in that: The system includes a DOC reactor (6), a DPF filter (7), and an SCR reactor (14) arranged sequentially and connected according to the direction of the waste gas flow. The DOC reactor (6) and the DPF filter (7) are integrated into a cylindrical unit structure, and a cyclone mixer (12) and a urea mixing pipe (13) are installed between the DOC reactor (6) and the SCR reactor (14). The upstream end of the DOC reactor (6) is provided with a waste gas inlet (1), and the waste gas outlet is located at the downstream end of the SCR reactor (14). The catalytic reactor is provided with two urea nozzle seats and multiple corresponding sensor seats.

2. A catalytic reactor for a diesel engine according to claim 1, characterized in that: The two urea nozzle seats are the original urea nozzle seat (10) and the supplementary urea nozzle seat (11), wherein the original urea nozzle seat (10) is located at the inlet of the vortex mixer (12) and the supplementary urea nozzle seat (11) is located on the SCR mixing chamber; the two urea nozzle seats are on the same cross section and their central axes are 90° to each other.

3. A catalytic reactor for a diesel engine according to claim 2, characterized in that: The original sensor seats corresponding to the original urea nozzle seat (10) include exhaust temperature sensor seat T1 (4), NOx sensor seat N3 (16) and exhaust temperature sensor seat T4 (18), wherein the exhaust temperature sensor seat T1 (4) is located at the rear end of the aforementioned DPF filter (7), and the NOx sensor seat N3 (16) and exhaust temperature sensor seat T4 (18) are located in the exhaust gas outlet area.

4. A catalytic reactor for a diesel engine according to claim 2, characterized in that: The supplementary spray sensor seat corresponding to the supplementary spray urea nozzle seat (11) includes NOx sensor seat N1 (5), exhaust temperature sensor seat T2 (8), NOx sensor seat N2 (15), exhaust temperature sensor seat T3 (17), as well as front differential pressure sensor seat (2) and rear differential pressure sensor seat (3). NOx sensor seat N1 (5) is set on the front wall of the above-mentioned DOC reactor (6), exhaust temperature sensor seat T2 (8) is set on the rear end of the above-mentioned DPF filter (7), and NOx sensor seat N2 (15) and exhaust temperature sensor seat T3 (17) are set on the rear end of the above-mentioned SCR reactor (14). The above-mentioned front differential pressure sensor seat (2) and rear differential pressure sensor seat (3) are respectively set on the front and rear side walls of the above-mentioned DOC reactor (6).

5. A catalytic reactor for a diesel engine according to claim 1, characterized in that: The DOC reactor (6), DPF filter (7) and SCR reactor (14) are arranged in a U-shaped structure.

6. A catalytic reactor for a diesel engine according to claim 1, characterized in that: The DOC reactor (6) and the DPF filter (7) are connected by clamps; the cyclone mixer (12) and the urea mixing pipe (13) are fixed by flanges.

7. A catalytic reactor for a diesel engine according to claim 1, characterized in that: The corresponding sensors can be detachably installed in different sensor holders and are sealed.

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