Reducing agent injection quantity accurate control device based on SCR system
By using a multi-pump parallel and redundant design for the reductant injection quantity control device, the problem of inaccurate injection quantity caused by excessive distance between the spray gun and the supply pump in the SCR system is solved. This achieves precise control of the reductant injection quantity and atomization effect, reduces equipment costs, and meets the high emission requirements of multiple engines.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENAN DIESEL ENGINE IND
- Filing Date
- 2025-06-26
- Publication Date
- 2026-05-01
AI Technical Summary
In existing SCR systems, the excessive distance between the spray gun and the reducing agent pipeline supplying the pump leads to inaccurate adjustment of the reducing agent injection volume, affecting the reducing agent injection volume and potentially causing problems such as excessive ammonia escape or substandard exhaust emissions.
The system employs a connection logic of multiple pumps in parallel, main line pressure stabilization, branch line precise metering, and gas-liquid synergistic atomization. Redundancy design enhances system reliability. The injection regulating valve precisely controls the amount of reducing agent injected. Compressed air pressure stabilization pipelines and reducing agent pressure stabilization pipelines are connected one-to-one. The injection regulating valve is positioned close to the spray gun to reduce pipeline length and ensure pressure stability.
It achieves precise control of the reducing agent injection amount, ensuring injection accuracy and atomization effect, reducing equipment costs, adapting to the high emission requirements of multiple engines, and ensuring that exhaust emissions meet standards.
Smart Images
Figure CN224187645U_ABST
Abstract
Description
Precise control device for reducing agent injection based on SCR system Technical Field
[0001] This utility model relates to a device, and more particularly to a device for precise control of the amount of reducing agent injected based on an SCR system. Background Technology
[0002] With the gradual implementation of emission regulations, air pollutants from mobile sources have been effectively controlled. The main factor in measuring the effectiveness of this control is the diesel engine emission control system. The SCR (Selective Catalytic Reduction) system is a key technology system used to reduce nitrogen oxide (NOx) emissions from engine exhaust. Its core working principle involves injecting a suitable amount of reducing agent into the exhaust pipe. The reducing agent undergoes ammoniation at high temperatures to generate ammonia. Under the action of a catalyst, the ammonia reduces NOx in the exhaust gas into harmless nitrogen (N2) and water (H2O), thereby achieving the goal of reducing pollutant emissions.
[0003] A typical engine SCR system requires at least one set of reductant storage tank, supply pump, pressure regulator, flow meter, injection control valve, compressed air solenoid valve, spray gun purging solenoid valve, and spray gun. In construction machinery or shipbuilding companies, the reductant storage tank and supply pump are installed indoors for easy access to reductant and equipment operation. The engine is also installed indoors, with the exhaust pipe extending through the building to a certain height on the ship's deck to discharge gases outdoors. Due to environmental regulations, the exhaust pipe becomes relatively longer after the SCR system is installed, and the spray gun is positioned further from the supply pump. The routing of the compressed air and reductant supply pipes is often determined based on actual conditions. Even with the same design configuration, different pipe pressure losses, coupled with pump output pressure differences, will cause pressure differences before the reductant injection quantity adjustment device. This pressure difference affects the accuracy of the reductant injection quantity adjustment, thus affecting the injection quantity. Insufficient injection quantity will not meet requirements, while excessive injection quantity will cause excessive ammonia escape, resulting in substandard exhaust emissions. Summary of the Invention
[0004] The purpose of this invention is to provide a precise control device for the amount of reducing agent injected based on an SCR system. Addressing the problem of excessively long distance between the spray gun and the reducing agent supply pump pipeline, this device can ensure the stability of the reducing agent and auxiliary injection compressed air pressure while effectively reducing equipment costs. This ensures injection accuracy and atomization effect, and greatly reduces design and product manufacturing costs.
[0005] To achieve the above objectives, the technical solution of this utility model is: a precise control device for the injection volume of reducing agent based on an SCR system, comprising a reducing agent storage tank, a supply pump, a pressure stabilizing valve, a flow meter, an injection regulating valve, a spray gun, a compressed air solenoid valve, and a spray gun purging solenoid valve. The reducing agent storage tank is connected to the input end of the supply pump, and the output end of the supply pump is connected to the reducing agent pressure stabilizing pipeline UR. A pressure stabilizing valve is installed on the reducing agent pressure stabilizing pipeline UR. Multiple branches are led out from the reducing agent pressure stabilizing pipeline UR. Each branch is equipped with a flow meter, a reducing agent supply solenoid valve, and an injection regulating valve, and is then connected to the input end of the spray gun. The output end of the spray gun is inserted into an exhaust pipe.
[0006] The device also includes a compressed air pressure stabilizing line AR, from which compressed air flows in. A pressure regulating valve is installed on the compressed air pressure stabilizing line AR. Multiple branches are led out from the compressed air pressure stabilizing line AR. Each branch is equipped with a compressed air solenoid valve and is also connected to the input end of the spray gun. The output end of the spray gun is inserted into the exhaust pipe.
[0007] The branch lines from the compressed air pressure stabilizing pipeline AR and the branch lines from the reducing agent pressure stabilizing pipeline UR are connected in a one-to-one correspondence, and a spray gun purging solenoid valve is installed between the two.
[0008] Furthermore, the connection point between the compressed air pressure stabilizing pipeline AR branch and the reducing agent pressure stabilizing pipeline UR branch is located between the reducing agent supply solenoid valve and the injection regulating valve.
[0009] Furthermore, the reducing agent storage tank is connected in parallel by multiple supply pumps, and the output ends of the multiple supply pumps are connected to the reducing agent pressure stabilizing pipeline UR.
[0010] Furthermore, the reducing agent storage tank is supplied by three pumps connected in parallel.
[0011] Furthermore, a pump control solenoid valve is installed between the reducing agent storage tank and each supply pump.
[0012] Compared with the prior art, the beneficial effects of this utility model are:
[0013] 1. The redundant SCR injection system, through the connection logic of "multi-pump parallel operation → main line pressure stabilization → branch line precise metering → gas-liquid synergistic atomization," ensures both the accuracy of reductant injection and enhances system reliability through redundant design of pumps, valves, and pipelines, making it suitable for scenarios with multiple engines and high emission requirements. This device can effectively reduce equipment costs while ensuring the stability of reductant and auxiliary injection compressed air pressure, thereby guaranteeing injection accuracy and atomization effect. Furthermore, the number of engine aftertreatment systems can be flexibly increased or decreased, significantly reducing design and production costs.
[0014] 2. The injection regulating valve precisely adjusts the injection quantity of the reducing agent by controlling its opening degree. Based on the engine's operating conditions and exhaust emission requirements, it adjusts the reducing agent supply in real time to ensure that the injection quantity matches the concentration of nitrogen oxides (NOx) in the exhaust gas, thereby achieving effective NOx reduction and ensuring that exhaust emissions meet environmental standards. The injection regulating valve is installed on the branch line between the common reducing agent pressure stabilizing line and the injection lines of each engine exhaust line. The pressure stability before and after this line directly affects the injection accuracy of the reducing agent. By precisely controlling the valve opening degree, the pressure of the reducing agent can be kept stable during injection, thereby improving the accuracy and consistency of the injection.
[0015] 3. Due to variations in exhaust pipe length and routing between different engines, pressure losses in the reducing agent piping can differ. Positioning the injection regulating valve close to the spray gun significantly shortens the piping length, reduces the piping's impact on pressure stability, and further ensures injection accuracy.
[0016] 4. Multiple engines share a reducing agent storage tank, supply pump set, reducing agent pressure stabilizing pipe, and compressed air pressure stabilizing pipe. Through effective control of the supply pump set head, the laying position of the reducing agent pressure stabilizing pipe and the compressed air pressure stabilizing pipe, costs are saved while ensuring the stability of the reducing agent and compressed air pressure used by each engine, thereby achieving precise control of the injection quantity. Attached Figure Description
[0017] Figure 1 is a block diagram illustrating the working principle of this utility model.
[0018] Figure 2 is a schematic diagram of the equipment installation of this utility model.
[0019] In the diagram, 1 is the reducing agent storage tank, 2 is the supply pump, 3 is the pressure stabilizing valve, 34 is the compressed air pressure regulating valve, 4 is the flow meter, 5 is the injection regulating valve, 6 is the spray gun, 8 is the compressed air solenoid valve, 9 is the spray gun purging solenoid valve, 10 is the reducing agent supply solenoid valve, and 11 is the pump control solenoid valve. Detailed Implementation
[0020] The present invention will now be described in further detail with reference to the accompanying drawings.
[0021] Example 1: As shown in Figures 1-2, a precise control device for reducing agent injection volume based on an SCR system includes a reducing agent storage tank 1, a supply pump 2, a pressure regulating valve 33, a flow meter 4, an injection regulating valve 5, a spray gun 6, a compressed air solenoid valve 8, and a spray gun purging solenoid valve 9. The reducing agent storage tank 1 is connected to the input end of the supply pump 2 and is used to store reducing agent (such as urea solution). The output end of the supply pump 2 is connected to the reducing agent pressure regulating pipeline UR. The supply pump 2 draws reducing agent from the storage tank 1 and delivers it to the common reducing agent pressure regulating pipeline UR. A pressure regulating valve 33 is installed on the UR pipeline. The supply pump 2 delivers the reducing agent to this pipeline and maintains stable pressure through the pressure regulating valve 33. Multiple branches are led out from the reducing agent pressure regulating pipeline UR. Each branch is equipped with a flow meter 4, an injection regulating valve 5, and is connected to the input end of the spray gun 6. The injection regulating valve 5 controls the amount of reducing agent injected. The output end of the spray gun 6 is inserted into the exhaust pipe 7, and the spray gun 6 atomizes the reducing agent and sprays it into the exhaust pipe 7. Each branch line is equipped with an injection regulating valve 5, which can independently adjust the reducing agent injection volume, improving the injection accuracy of the device. While ensuring injection accuracy, this device adopts a resource-sharing approach to reduce equipment costs, offering significant advantages for applications with multiple engine SCR systems in the same region.
[0022] This device also includes a compressed air pressure regulating line AR, through which compressed air flows in. A pressure regulating valve 34 is installed on the compressed air pressure regulating line AR to adjust and set the compressed air pressure within the line and maintain stability. Multiple branches extend from the compressed air pressure regulating line AR, each branch equipped with a compressed air solenoid valve 8 and also connected to the input end of the spray gun 6. The output end of the spray gun 6 is inserted into the exhaust pipe 7.
[0023] The branch lines from the compressed air pressure stabilizing pipeline AR are connected one-to-one with the multiple branches from the reducing agent pressure stabilizing pipeline UR, and a spray gun purging solenoid valve 9 is installed between them. The connection end between the compressed air pressure stabilizing pipeline AR branch and the reducing agent pressure stabilizing pipeline UR branch is located between the reducing agent supply solenoid valve 10 and the injection regulating valve 5.
[0024] During operation, the reducing agent supply solenoid valve 10 and the compressed air solenoid valve 8 are opened. Compressed air in the compressed air stabilizing pipeline AR enters the spray gun through the compressed air solenoid valve 8. The supply pump 2 draws the reducing agent from the storage tank 1 and delivers it to the common reducing agent stabilizing pipeline UR, and then enters the spray gun 6. The injection regulating valve 5 regulates the injection volume of the reducing agent. After the reducing agent injection is completed, the spray gun purging solenoid valve 9 and the compressed air solenoid valve 8 are opened to enter the purging mode.
[0025] Furthermore, the reducing agent storage tank 1 is connected in parallel by multiple supply pumps 2, and the output ends of the multiple supply pumps 2 are connected to the reducing agent pressure stabilizing pipeline UR. The reducing agent pressure stabilizing pipeline UR is a common pressure stabilizing pipeline. For each engine exhaust SCR system, the pipe leading from the reducing agent pressure stabilizing pipeline UR to the spray gun 6 is very short. An injection regulating device (flow meter 4, injection regulating valve 5) is installed between the reducing agent pressure stabilizing pipeline UR and the spray gun 6. The pressure stabilizing valve 33 ensures that the pressure of the pressure stabilizing pipeline is adjustable and the reducing agent pressure is stable. The pressure before the injection regulating device is stable, providing conditions for precise adjustment of the injection volume.
[0026] Furthermore, the reducing agent storage tank 1 is connected in parallel by three supply pumps 2. The supply pumps 2 are used in a one-in-one-standby or two-in-one-standby reducing agent supply mode. The number of pumps is determined according to the number of engines and the flow rate of the supply pumps to improve the reliability of the system.
[0027] Furthermore, a pump control solenoid valve 11 is installed between the reducing agent storage tank 1 and each supply pump 2, and each supply pump 2 is equipped with a pump control solenoid valve 11.
[0028] During installation, due to the short distance between the engine exhaust pipe 7 and the reducing agent pressure stabilizing line UR, the reducing agent pressure stabilizing line UR horizontally covers all engine exhaust pipe injection lines. The supply pump 2 delivers the reducing agent to the reducing agent pressure stabilizing line UR. A pressure stabilizing valve 33 is installed on the reducing agent pressure stabilizing line UR to ensure stable reducing agent pressure within the line. All engine reducing agent is led out from the reducing agent pressure stabilizing line UR through branch lines to the injection regulating valve 5, and then from the injection regulating valve 5 into the spray gun 6, thus being sprayed into the exhaust pipe. This configuration of the reducing agent injection line branches is short, and the pressure after stabilization of each device is basically consistent with the pipeline pressure, resulting in good pressure stability. The compressed air lines are configured similarly, with a compressed air pressure stabilizing line AR installed near the engine exhaust pipe 7. Compressed air is led out from the compressed air pressure stabilizing line AR through branch lines to the spray gun 6.
[0029] This device addresses the issue of excessively long reducing agent pipelines between the spray gun and the supply pump. It effectively reduces equipment costs while ensuring stable pressure of the reducing agent and auxiliary injection compressed air, thereby guaranteeing spray accuracy and atomization effect. By adopting a resource-sharing approach, the number of engine aftertreatment systems can be flexibly increased or decreased while ensuring spray accuracy, greatly reducing design and product manufacturing costs.
Claims
1. A precise control device for reducing agent injection volume based on an SCR system, comprising a reducing agent storage tank (1), a supply pump (2), a pressure regulating valve (33), a flow meter (4), an injection regulating valve (5), a spray gun (6), a compressed air solenoid valve (8), and a spray gun purging solenoid valve (9), characterized in that, The reducing agent storage tank (1) is connected to the input end of the supply pump (2), and the output end of the supply pump (2) is connected to the reducing agent pressure stabilizing pipeline UR. A pressure stabilizing valve (33) is installed on the reducing agent pressure stabilizing pipeline UR. Multiple branches are led out from the reducing agent pressure stabilizing pipeline UR. Each branch is equipped with a flow meter (4), a reducing agent supply solenoid valve (10), and an injection regulating valve (5), and is then connected to the input end of the spray gun (6). The output end of the spray gun (6) is inserted into the exhaust pipe (7). This device also includes a compressed air pressure stabilizing pipeline AR. Compressed air flows in from the inlet of the compressed air stabilizing pipeline AR. The compressed air stabilizing pipeline AR is equipped with a pressure regulating valve (34). Multiple branches are led out from the compressed air stabilizing pipeline AR. Each branch is equipped with a compressed air solenoid valve (8) and is also connected to the input end of the spray gun (6). The output end of the spray gun (6) is inserted into the exhaust pipe (7). The branches led out from the compressed air stabilizing pipeline AR are connected one-to-one with the branches led out from the reducing agent stabilizing pipeline UR, and a spray gun purging solenoid valve (9) is installed between them.
2. The precise control device for reducing agent injection based on an SCR system as described in claim 1, characterized in that, The connection point between the compressed air pressure stabilizing pipeline AR branch and the reducing agent pressure stabilizing pipeline UR branch is located between the reducing agent supply solenoid valve (10) and the injection regulating valve (5).
3. The precise control device for reducing agent injection based on an SCR system as described in claim 2, characterized in that, The reducing agent storage tank (1) is connected in parallel by multiple supply pumps (2), and the output ends of the multiple supply pumps (2) are connected to the reducing agent pressure stabilizing pipeline UR.
4. The precise control device for reducing agent injection based on an SCR system as described in claim 3, characterized in that, The reducing agent storage tank (1) is connected in parallel by three supply pumps (2).
5. The precise control device for reducing agent injection based on an SCR system as described in claim 4, characterized in that, A pump control solenoid valve (11) is installed between the reducing agent storage tank (1) and each supply pump (2).