Urea injection device for upgrading emissions of a vehicle in use

Abstract

The utility model discloses a kind of in-use vehicle emission upgrading urea injection device, including original vehicle urea injection control system and auxiliary urea injection control system, two systems are including independent urea tank, urea metering pump, urea injection pipe, urea nozzle, controller and multiple sensors, urea nozzle and multiple sensors are respectively installed in the specific position of in-use vehicle exhaust system. Original vehicle urea injection control system works drive according to the data collected by engine controller;Auxiliary urea injection control system collects exhaust temperature, SCR differential pressure, front NOx concentration and other signal data through controller, calculates supplemental urea injection rate and executes injection at any time;Also, monitor key parameters through display and carry out fault alarm. The utility model is simple in structure, is upgraded to double circuit parallel urea injection control system, improves NOx elimination efficiency, so that the in-use vehicle of national four or national five emission stage meets national six emission standard.

Description

Technical Field

[0001] This utility model relates to the field of diesel engine exhaust aftertreatment technology, specifically to a urea injection device for upgrading emissions in in-use vehicles. Background Technology

[0002] Selective Catalytic Reduction (SCR) technology can effectively solve the NOx emission problem while ensuring power and economy, meeting environmental regulations. This technology has been widely used in the field of lean-burn engines for automobiles. The SCR system consists of a urea injection device, a urea mixer, and an SCR reactor. Its basic principle is to inject a reducing agent into the diesel engine exhaust pipe through the urea injection device. The reducing agent reacts with NOx under the action of a catalyst, controlling NOx emissions within the regulatory limits.

[0003] The urea injection system calculates the required urea injection rate based on the engine operating conditions, achieving precise control of the injection quantity and ensuring that the urea achieves ideal spray characteristics after being injected. Under the action of the mixing device, the urea is rapidly mixed with the high-temperature exhaust gas, causing the urea to decompose into NH3 through heat absorption. Finally, the NH3 reacts with NOx under the action of the catalyst, achieving the purpose of eliminating NOx emissions.

[0004] Depending on the atomization method, urea injection systems are mainly divided into two types: air-assisted and non-air-assisted. Non-air-assisted injection uses a urea pump to generate a high-pressure urea solution. The urea injection rate is metered by controlling the opening frequency and duration of the nozzles. The high-pressure urea solution is atomized as it passes through the small orifice of the urea nozzle. Air-assisted injection uses a metering pump to meter the urea. Compressed air enters the urea pump through the intake pipe. The urea solution and compressed air mix in the metering pump, and then the mixture is atomized and injected into the engine exhaust gas through the urea injection pipe at the nozzle end using high-pressure air. Currently available conventional air-assisted urea injection systems cannot meet the emission targets for current vehicle exhaust. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing vehicle exhaust systems in meeting current national emission standards, and to provide an upgraded urea injection device for in-use vehicle emissions.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a urea injection device for upgrading the emissions of in-use vehicles, including an original urea injection control system and an auxiliary urea injection control system. Both urea injection control systems include a urea injection system and a urea control system. The urea injection system includes a urea tank, a urea metering pump, a urea injection pipe, and a urea nozzle. The urea nozzle is installed on the urea mixing pipe at the front end of the SCR reactor. The urea control system includes a corresponding controller and multiple sensors, which are installed at designated locations in the exhaust system of the in-use vehicle.

[0007] Furthermore, the original vehicle urea injection control system includes an original vehicle urea injection system and an original vehicle urea control system. The original vehicle urea injection system includes an original urea tank, an original urea metering pump, an original urea injection pipe, and an original urea nozzle. The original urea metering pump is connected to the original urea tank through an original urea suction pipe and an original urea return pipe. The original urea metering pump is connected to the original urea nozzle through the original urea injection pipe. The original urea nozzle can be detachably installed on the urea mixing pipe at the front end of the SCR reactor. An original urea liquid level and temperature sensor is installed on the original urea tank.

[0008] Furthermore, the original vehicle urea control system includes an engine controller and original front exhaust temperature sensor, original rear exhaust temperature sensor, and original rear nitrogen oxide sensor. The original front exhaust temperature sensor is installed on the urea mixing pipe at the front end of the SCR reactor, and the original rear exhaust temperature sensor and original rear nitrogen oxide sensor are both installed on the exhaust pipe of the vehicle's exhaust system.

[0009] The aforementioned original front exhaust temperature sensor, original rear exhaust temperature sensor, original rear nitrogen oxygen sensor, as well as the original urea tank and original urea metering pump are all connected to the engine controller.

[0010] Furthermore, the auxiliary urea injection control system includes an auxiliary urea injection system and an auxiliary urea control system. The auxiliary urea injection system includes an auxiliary urea tank, an auxiliary urea metering pump, an auxiliary urea injection pipe, and an auxiliary urea nozzle. The auxiliary urea metering pump is connected to the auxiliary urea tank through a urea suction pipe and a urea return pipe. The auxiliary urea metering pump is connected to the auxiliary urea nozzle through the auxiliary urea injection pipe. The auxiliary urea nozzle is detachably installed on the urea mixing pipe at the front end of the SCR reactor. A urea level and temperature sensor is installed on the auxiliary urea tank.

[0011] Furthermore, the auxiliary urea control system includes a new controller and a front NOx sensor, a front exhaust temperature sensor, a differential pressure sensor, a rear exhaust temperature sensor, and a rear nitrogen oxide sensor. The front NOx sensor is installed on the exhaust gas intake pipe of the vehicle's exhaust system, the front exhaust temperature sensor is installed on the cylinder wall behind the DPF filter in the vehicle's exhaust system, the differential pressure sensor is installed across the front and rear ends of the SCR reactor, and the rear exhaust temperature sensor and the rear nitrogen oxide sensor are installed on the exhaust gas exhaust pipe of the vehicle's exhaust system.

[0012] The aforementioned front NOx sensor, front exhaust temperature sensor, differential pressure sensor, rear exhaust temperature sensor, rear nitrogen oxide sensor, as well as the auxiliary urea tank and auxiliary urea metering pump, are all connected to the newly added controller.

[0013] Furthermore, external compressed gas is connected to the oil-water separator via a high-pressure pipeline. The oil-water separator is then connected to the urea metering pump in the original vehicle urea injection control system and the auxiliary urea injection control system via two compressed air pipelines.

[0014] Furthermore, it also includes a display screen connected to the newly added controller via a cable. The display screen monitors key parameters in real time, and immediately sends an alarm to the customer in case of system malfunction or insufficient urea level.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention adds a relatively independent urea injection control system without affecting the original vehicle urea injection control system, upgrading it into a dual-path parallel urea injection control system; and the newly added urea injection control system manages the status through corresponding sensors to supplement the urea injection rate, while working with a high-efficiency SCR reactor to achieve higher NOx elimination efficiency, so that the NOx emission control of the vehicle in use meets the China VI emission standard. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the urea injection device for upgrading vehicle emissions according to this utility model; In the diagram: 1. Exhaust gas inlet pipe; 2. Front NOx sensor; 3. DOC reactor; 4. DPF filter; 5. Auxiliary urea nozzle; 6. Original front exhaust temperature sensor; 7. Original urea nozzle; 8. SCR reactor; 9. Rear exhaust temperature sensor; 10. Rear nitrogen oxide sensor; 11. Original rear exhaust temperature sensor; 12. Original rear nitrogen oxide sensor; 13. Differential pressure sensor; 14. Front exhaust temperature sensor; 15. Display; 16. Auxiliary urea injection. 17. Auxiliary urea metering pump; 18. Urea return pipe; 19. New controller; 20. Original urea injection pipe; 21. Original urea metering pump; 22. Original urea return pipe; 23. Engine controller; 24. Urea suction pipe; 25. Oil-water separator; 26. Compressed air pipe; 27. Auxiliary urea tank; 28. Urea level and temperature sensor; 29. ​​Original urea suction pipe; 30. Original urea tank; 31. Original urea level and temperature sensor. Detailed Implementation

[0017] It should be noted that in the description of this utility model, terms such as "upper", "lower", "front", "rear", "one end", "the other end" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the 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. They should not be construed as limitations on this utility model.

[0018] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, the terms "set up," "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 starting end of the exhaust gas flow direction as the front): like Figure 1 As shown, an in-use vehicle emission upgrade urea injection device includes an original vehicle urea injection control system and an auxiliary urea injection control system. This is equivalent to adding a supplementary urea injection control system to the original vehicle urea injection control system. Both urea injection control systems include a urea injection system and a urea control system. The urea injection system includes a urea tank, a urea metering pump, a urea injection pipe, and a urea nozzle. The urea nozzle is installed on the urea mixing pipe at the front end of the SCR reactor. The urea control system includes a corresponding controller and multiple sensors, which are installed at designated locations in the in-use vehicle exhaust system.

[0020] The vehicle exhaust system includes an exhaust gas inlet pipe 1, a DOC reactor 3, a DPF filter 4, a urea mixing pipe, an SCR reactor 8, and an exhaust gas outlet pipe, which are arranged sequentially and fixedly connected according to the exhaust gas flow direction. The DOC reactor 3 and the DPF filter 4 are connected and fixedly integrated into a cylindrical unit structure by clamps. Two urea nozzle seats are arranged sequentially at intervals on the urea mixing pipe, which can respectively install two urea nozzles in the two sets of urea injection control systems.

[0021] The original vehicle urea injection control system includes an original vehicle urea injection system and an original vehicle urea control system. The original vehicle urea injection system includes an original urea tank 30, an original urea metering pump 21, an original urea injection pipe 20, and an original urea nozzle 7. The original urea metering pump 21 is connected to the original urea tank 30 through an original urea suction pipe 29 and an original urea return pipe 22. An original urea liquid level and temperature sensor 31 is installed on the original urea tank 30. The original urea metering pump 21 is connected to the original urea nozzle 7 through the original urea injection pipe 20. The original urea nozzle 7 is detachably installed on the urea mixing pipe at the front end of the SCR reactor 8. The nozzle end of the original urea nozzle 7 extends into the urea mixing pipe to perform urea spraying operations. The original vehicle urea control system includes an engine controller 23 and original front exhaust temperature sensor 6, original rear exhaust temperature sensor 11, and original rear nitrogen oxygen sensor 12. The original front exhaust temperature sensor 6 is installed on the urea mixing pipe at the front end of the SCR reactor 8, located in front of the original urea nozzle 7; the original rear exhaust temperature sensor 11 and the original rear nitrogen oxygen sensor 12 are installed sequentially on the above-mentioned exhaust pipe.

[0022] The aforementioned original front exhaust temperature sensor 6, original rear exhaust temperature sensor 11, original rear nitrogen oxygen sensor 12, as well as the original urea tank 30 and original urea metering pump 21 are all connected to the engine controller 23. The engine controller 23 controls the urea injection of the original urea nozzle 7 to ensure the normal operation of the original vehicle.

[0023] The auxiliary urea injection control system includes an auxiliary urea injection system and an auxiliary urea control system. The auxiliary urea injection system includes an auxiliary urea tank 27, an auxiliary urea metering pump 17, an auxiliary urea injection pipe 16, and an auxiliary urea nozzle 5. The auxiliary urea metering pump 17 is connected to the auxiliary urea tank 27 through a urea suction pipe 24 and a urea return pipe 18. A urea level and temperature sensor 28 is installed on the auxiliary urea tank 27. The auxiliary urea metering pump 17 is connected to the auxiliary urea nozzle 5 through the auxiliary urea injection pipe 16. The auxiliary urea nozzle 5 is detachably installed in the urea nozzle seat on the urea mixing pipe behind the DPF filter 4, located in front of the original urea nozzle 7, with the two spaced apart. The nozzle end of the auxiliary urea nozzle 5 also extends into the urea mixing pipe to perform urea spraying operations. The auxiliary urea control system includes a newly added controller 19, a front NOx sensor 2, a front exhaust temperature sensor 14, a differential pressure sensor 13, a rear exhaust temperature sensor 9, and a rear nitrogen oxide sensor 10. The front NOx sensor 2 is installed on the exhaust gas inlet pipe 1; the front exhaust temperature sensor 14 is installed on the cylinder wall behind the DPF filter 4; the differential pressure sensor 13 is installed across the front and rear ends of the SCR reactor 8 to monitor the pressure difference changes before and after the SCR reactor 8 in real time; and the rear exhaust temperature sensor 9 and the rear nitrogen oxide sensor 10 are installed sequentially on the exhaust gas outlet pipe.

[0024] The aforementioned front NOx sensor 2, front exhaust temperature sensor 14, differential pressure sensor 13, rear exhaust temperature sensor 9, rear nitrogen and oxygen sensor 10, as well as the auxiliary urea tank 27 and auxiliary urea metering pump 17, are all connected to the newly added controller 19. The newly added controller 19 is also connected to an external display 15 via wiring. The display 15 can monitor key parameters in real time, and will immediately issue an alarm to the customer if the system malfunctions or the urea level is insufficient.

[0025] External compressed gas from the air compressor cylinder is connected to the oil-water separator 25 via a high-pressure pipeline. After passing through the oil-water separator 25, it is divided into two paths, which are connected to the original urea metering pump 21 in the original vehicle urea injection control system and the auxiliary urea metering pump 17 in the auxiliary urea injection control system via compressed air pipe 26, respectively. The compressed air is mixed with the urea solution.

[0026] The specific operating principle is as follows: a urea injection control method corresponding to an in-use vehicle emission upgrade urea injection device includes 5 control states: state 0 - self-check, state 1 - waiting, state 2 - pre-injection, state 3 - injection, and state 4 - purging. The specific control steps include the following: Step 1: After the newly added controller 19 is powered on, the urea injection control system enters state 0 and checks the status of electrical components. If the electrical components have no problems with their self-test, the urea injection control system enters state 1. If the electrical components fail the self-test, the system remains in state 0 until the problem is resolved.

[0027] Step two: After the engine starts, the aforementioned sensors collect and transmit signals; currently, exhaust temperature sensor 14 detects that the front exhaust temperature is greater than the threshold T. pr The auxiliary urea injection control system enters state 2; otherwise, it remains in state 1.

[0028] Step 3, Pre-injection process. After entering state 2, the auxiliary urea metering pump 17 draws urea solution from the auxiliary urea tank 27 through the urea suction pipe 24, filling the auxiliary urea metering pump 17 with urea solution. The extraction continues for a certain time (t). f When the auxiliary urea metering pump 17 is filled with urea solution, it starts to return liquid through the urea return pipe 18. At the same time, the air passage inside the auxiliary urea metering pump 17 is opened, and the gas-liquid mixture of compressed air and urea solution enters the auxiliary urea injection pipe 16.

[0029] After the above operations are completed, the auxiliary urea metering pump 17 stops pumping liquid and at the same time closes the return channel of the urea return pipe 18. The auxiliary urea injection control system enters state 3, and can inject at any time after the injection conditions are met.

[0030] Step 4: The current exhaust temperature sensor 14 monitors the exhaust temperature as < threshold T. Do When the engine stops, the liquid injection is stopped; after the engine stops, the temperature gradually decreases, and the front exhaust temperature sensor 14 monitors the front exhaust temperature as being less than the threshold T. Pu The auxiliary urea injection control system enters state 4. The auxiliary urea metering pump 17, through its internal mechanism, blows the urea solution from its interior, as well as from the auxiliary urea injection pipe 16 and the auxiliary urea nozzle 5, into the urea mixing pipe, continuing for several seconds (t). c After this process is completed, it will return to state 1, completing one work cycle.

[0031] At the same time, the original vehicle urea injection control system performs the above steps simultaneously to inject urea solution.

[0032] The continuous injection of urea solution in state 3 above is linked to state 2 above. Currently, the exhaust temperature sensor 14 monitors an exhaust temperature greater than the threshold T. Do When the required urea injection rate is greater than the pre-stored amount in the metering pump, the new controller 19 drives the auxiliary urea metering pump 17 to extract the urea solution from the corresponding urea tank.

[0033] The urea solution is atomized into urea droplets by compressed air through the urea nozzle. After being sprayed into the urea mixing pipe, the urea droplets absorb heat and decompose into NH3 in the high-temperature exhaust gas, and are uniformly mixed with the exhaust gas. When the exhaust gas carrying NH3 flows through the SCR reactor 8, the NOx in the exhaust gas reacts with NH3 to generate harmless N2, thereby achieving the purpose of reducing or eliminating NOx emissions.

[0034] When the front exhaust temperature sensor 14 fails, the detection value of the rear exhaust temperature sensor 9 will replace the front exhaust temperature, and the system can operate in a degraded manner.

[0035] The nitrogen oxide sensor 10 is used to monitor the NOx concentration. If the concentration exceeds the target value, an alarm for NOx exceeding the standard will be triggered.

[0036] 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 urea injection device for upgrading emissions from in-use vehicles, characterized in that: The system includes the original vehicle urea injection control system and the auxiliary urea injection control system. Both urea injection control systems include a urea injection system and a urea control system. The urea injection system includes a urea tank, a urea metering pump, a urea injection pipe and a urea nozzle. The urea nozzle is installed on the urea mixing pipe at the front end of the SCR reactor (8). The urea control system includes a corresponding controller and multiple sensors. The multiple sensors are installed at designated locations in the exhaust system of the vehicle.

2. The urea injection device for upgrading emissions in in-use vehicles according to claim 1, characterized in that: The original vehicle urea injection control system includes an original vehicle urea injection system and an original vehicle urea control system. The original vehicle urea injection system includes an original urea tank (30), an original urea metering pump (21), an original urea injection pipe (20), and an original urea nozzle (7). The original urea metering pump (21) is connected to the original urea tank (30) through an original urea suction pipe (29) and an original urea return pipe (22). The original urea metering pump (21) is connected to the original urea nozzle (7) through the original urea injection pipe (20). The original urea nozzle (7) can be detachably installed on the urea mixing pipe at the front end of the above-mentioned SCR reactor (8). An original urea liquid level and temperature sensor (31) is installed on the original urea tank (30).

3. The urea injection device for upgrading emissions in in-use vehicles according to claim 2, characterized in that: The original vehicle urea control system includes an engine controller (23) and an original front exhaust temperature sensor (6), an original rear exhaust temperature sensor (11), and an original rear nitrogen oxygen sensor (12). The original front exhaust temperature sensor (6) is installed on the urea mixing pipe at the front end of the SCR reactor (8), and the original rear exhaust temperature sensor (11) and the original rear nitrogen oxygen sensor (12) are both installed on the exhaust pipe of the vehicle exhaust system. The aforementioned original front exhaust temperature sensor (6), original rear exhaust temperature sensor (11), original rear nitrogen oxygen sensor (12), original urea tank (30), and original urea metering pump (21) are all connected to the engine controller (23).

4. The urea injection device for upgrading emissions in in-use vehicles according to claim 1, characterized in that: The auxiliary urea injection control system includes an auxiliary urea injection system and an auxiliary urea control system. The auxiliary urea injection system includes an auxiliary urea tank (27), an auxiliary urea metering pump (17), an auxiliary urea injection pipe (16), and an auxiliary urea nozzle (5). The auxiliary urea metering pump (17) is connected to the auxiliary urea tank (27) through a urea suction pipe (24) and a urea return pipe (18). The auxiliary urea metering pump (17) is connected to the auxiliary urea nozzle (5) through the auxiliary urea injection pipe (16). The auxiliary urea nozzle (5) is detachably installed on the urea mixing pipe at the front end of the SCR reactor (8). A urea level and temperature sensor (28) is installed on the auxiliary urea tank (27).

5. The urea injection device for upgrading emissions in in-use vehicles according to claim 4, characterized in that: The auxiliary urea control system includes a new controller (19) and a front NOx sensor (2), a front exhaust temperature sensor (14), a differential pressure sensor (13), a rear exhaust temperature sensor (9), and a rear nitrogen oxide sensor (10). The front NOx sensor (2) is installed on the exhaust gas inlet pipe (1) of the vehicle exhaust system, the front exhaust temperature sensor (14) is installed on the cylinder wall behind the DPF filter (4) in the vehicle exhaust system, the differential pressure sensor (13) is installed across the front and rear ends of the SCR reactor (8), and the rear exhaust temperature sensor (9) and the rear nitrogen oxide sensor (10) are installed on the exhaust gas outlet pipe of the vehicle exhaust system. The aforementioned front NOx sensor (2), front exhaust temperature sensor (14), differential pressure sensor (13), rear exhaust temperature sensor (9), rear nitrogen and oxygen sensor (10), as well as auxiliary urea tank (27) and auxiliary urea metering pump (17), are all connected to the newly added controller (19).

6. The urea injection device for upgrading emissions in in-use vehicles according to claim 1, characterized in that: External compressed gas is connected to the oil-water separator (25) via a high-pressure pipeline. The oil-water separator (25) is connected to the urea metering pump in the original vehicle urea injection control system and the auxiliary urea injection control system via a compressed air pipe (26).

7. A urea injection device for upgrading emissions in in-use vehicles according to claim 5, characterized in that: It also includes a display (15) which is connected to the newly added controller (19) via a line.

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