A post-processing liquid supply pipeline pressure detection device and method

Abstract

A post-treatment liquid supply pipeline pressure detection device includes a post-treatment supply module, a DCU control unit, a gas-assisted device, a pressure detector, and a nozzle. The post-treatment supply module includes a urea supply pump, and the gas-assisted device includes an air source and an air solenoid valve. Pressurized liquid generated by the urea supply pump and high-pressure gas generated by the air source converge in a mixing chamber, and the resulting gas-liquid multiphase fluid is output through the nozzle. The DCU control unit collects pressure sensor data to implement pipeline pressure detection and control.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine exhaust after-treatment, and in particular to a device and method for controlling the pressure of a liquid supply pipeline of an exhaust after-treatment system. Background Art

[0002] With the continuous improvement of environmental protection awareness, engine and vehicle emission standards are becoming increasingly stringent. At present, the use of NOx selective catalytic reduction (SCR) technology that can perform catalytic reduction treatment in an oxygen-rich environment is the mainstream technical route for NOx pollutant treatment.

[0003] SCR technology requires a metered injection of a 32.5% by weight urea-water solution (also called Diesel Exhaust Fluid (DEF) or AdBlue) into the diesel engine's exhaust. The high-temperature decomposition of the exhaust gas produces ammonia, which then mixes with the exhaust gas before entering the SCR catalytic converter. Under the action of the catalyst, the ammonia reacts with NOx and other gases in the engine exhaust, breaking NOx down into harmless N2 and H2O. If the DEF injection rate doesn't match the NOx content in the exhaust, or if the urea solution quality doesn't meet the requirements, either NOx won't be fully reduced and decomposed, increasing emissions, or a significant amount of ammonia will be released into the atmosphere, causing secondary pollution. Therefore, the urea solution delivery system requires precise metering. Furthermore, the degree of urea spraying is crucial for optimal catalytic performance.

[0004] For urea liquid metering supply devices, the existing ones mainly include pure liquid supply and gas-liquid mixed supply. The metering supply device generally includes a liquid supply pump end and a nozzle end. Considering the layout of the entire vehicle, the liquid supply end and the injection end need to be connected through a longer pipeline. Therefore, the pure liquid module needs to adopt a nozzle end metering form to ensure accuracy. Compared with the pure liquid supply device, the gas-assisted supply device has basically no loss of liquid flow in the pipeline due to the action of airflow, and a pump metering method can be used. The device is simple, low-cost, and has better stability and atomization effect. However, for the gas-assisted device, the control of its intake pressure has an important influence on the injection state of the device, and the gas pressure provided by the on-board air source is prone to fluctuations, so it is necessary to configure a pressure stabilization device and a pressure detection device. Summary of the Invention

[0005] In view of the above problems, the present invention aims to provide a urea supply module with simple structure, high reliability and good adaptability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a post-treatment liquid supply line pressure detection device, comprising a post-treatment supply module, a DCU control unit, a gas-assisted device, a pressure detector, and a nozzle. The post-treatment supply module includes a urea supply pump, and the gas-assisted device includes an air source and an air solenoid valve. The urea supply pump is a solenoid electromagnetic pump driven by the DCU control unit to generate pressurized liquid. The air solenoid valve is located downstream of the air source to control the flow of gas.

[0007] The pressurized liquid generated by the urea supply pump and the high-pressure gas generated by the gas source converge into a mixing chamber. The mixing chamber and the liquid supply pump may be integrally formed or connected via a liquid supply pipeline. The mixing chamber and the gas source may be connected via a gas pipeline, and the generated gas-liquid multiphase fluid is output through the nozzle. The mixing chamber and the nozzle are connected via a mixed liquid pipeline.

[0008] Furthermore, the pressure detector is connected in series to the gas flow path between the mixing chamber and the air solenoid valve, and is used to detect the gas pressure at the front end of the air solenoid valve and feed back the pressure information to the DCU control unit.

[0009] The pressure detector includes a package, through which the pressure detector is installed on the gas flow channel, and the detection port of the pressure detector is directly located in the flow channel without infinite hole interference.

[0010] For the post-processing liquid supply pipeline pressure detection device, the following pressure detection methods are included:

[0011] The working range of the pressure detector is set according to the gas source pressure, and the DCU pre-stores the pressure characteristic parameters of the pressure detector;

[0012] The DCU control unit presets a target pressure range value according to the gas pressure required by the post-processing supply module.

[0013] The above pressure detection method further includes a step of determining the effectiveness of the pressure detector:

[0014] The DCU control unit determines the effectiveness of the pressure detector by reading the pressure values of the air solenoid valve in the closed and open states, and makes judgments based on the changes in the measured pressure values when the solenoid valve is open and closed.

[0015] The DCU control unit determines the accuracy of the zero point position by reading the pressure detector data when the solenoid valve is closed. When the zero point position offset of the pressure detector is within 10%, the DCU controller can perform compensation correction.

[0016] Furthermore, the pressure detection method includes a step in which the DCU control unit determines the effectiveness of the air solenoid valve by reading the pressure values of the air solenoid valve in the closed and open states.

[0017] When the air solenoid valve is closed, if the pressure detector output data collected by the DCU control unit is greater than 2 bar, it is determined that the solenoid valve closure fails;

[0018] When the air solenoid valve is in the open state, when the pressure value collected by the DCU control unit is close to the zero pressure value, it is determined that the solenoid valve fails to open.

[0019] When the pressure detector and the air solenoid valve are valid, the DCU control unit compares the collected pressure detector data with the target pressure range; the fault alarm includes at least pipeline blockage and low pressure fault.

[0020] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of an embodiment of the post-processing liquid supply pipeline pressure detection device provided by the present invention.

[0022] Figure 2 This is a cross-sectional view of the pressure detector of the post-processing liquid supply pipeline pressure detection device provided by the present invention.

[0023] Figure 3 This is a logic diagram of the post-processing liquid supply pipeline pressure detection method provided by the present invention. DETAILED DESCRIPTION

[0024] The schematic diagram of the embodiment of the pressure detection device of the post-processing liquid supply pipeline 110 provided by the present invention is as follows: Figure 1 As shown, it includes a post-processing supply module 1, a DCU control unit 2, a gas-assisted device 3, a pressure detector 104 and a nozzle 106.

[0025] The post-treatment supply module 1 is used to provide urea solution and includes a urea supply pump 107. The urea supply pump 107 is a solenoid electromagnetic pump, which is driven and controlled by the DCU control unit 2 to quantitatively supply pressurized urea solution. The urea supply amount can be controlled by adjusting the driving frequency.

[0026] The gas-assisted device 3 includes an air source 100 and an air solenoid valve 108. The air source 100 may be a vehicle-mounted gas tank, and the air solenoid valve 108 is arranged downstream of the air source 100 to control the flow of gas.

[0027] The pressurized liquid generated by the urea supply pump 107 and the high-pressure gas generated by the gas source 100 merge into a mixing chamber 105 . The mixing chamber 105 and the urea supply pump 107 can be designed as one body or connected via a liquid supply pipeline 110 .

[0028] The mixing chamber 105 and the gas source 100 can be connected through a gas pipeline 109, and the gas pipeline 109 is connected to a quick-plug air connector (not shown in the figure). A one-way valve 103 is arranged downstream of the gas source 100 and opens in the direction of airflow to prevent the internal pressure from increasing when the pipeline is blocked, causing the fluid to flow back to the gas source 100.

[0029] The gas-liquid multiphase fluid generated within the mixing chamber 105 is output through the nozzle 106. The nozzle 106 can be a swirl multiphase flow nozzle 106 and include a quick-connect connector (not shown) that meets the SAE-J standard. The mixing chamber 105 and the nozzle 106 are connected by a mixed liquid pipeline 111, which is connected via a quick-connect connector.

[0030] Furthermore, the pressure detector 104 is connected in series to the gas flow channel between the mixing chamber 105 and the air solenoid valve 108, and is used to detect the gas pressure downstream of the air solenoid valve 108, and feed back the pressure information to the DCU control unit 2. The DCU control unit 2 judges the detected pressure data to determine whether there is a risk in the pipeline pressure.

[0031] like Figure 2 As shown, it is a cross-sectional view of the pressure detector 104 of the pressure detection device of the post-processing liquid supply pipeline 110 provided by the present invention. The above-mentioned pressure detector 104 is a pressure sensor. The pressure sensor includes a package 200. The pressure sensor is installed on the gas flow channel 201 through the package 200 and fixed by a hook 203. The detection port 202 of the pressure detector 104 is directly located in the flow channel without infinite hole interference, thereby ensuring the accuracy of pressure detection.

[0032] like Figure 3 FIG. 1 is a logic diagram of a pressure detection method for a post-processing liquid supply pipeline 110 provided by the present invention. The control method includes:

[0033] The step of setting the working range of the pressure detector 104 according to the pressure of the gas source 100, wherein the DCU pre-stores the pressure characteristic parameters of the pressure detector 104 (step 300);

[0034] The DCU control unit 2 presets a target pressure range value according to the gas pressure required by the post-processing supply module 1 (step 300 ).

[0035] Furthermore, the pressure detection method includes a step of determining the effectiveness of the pressure detector 104 (step 301):

[0036] The determination of the effectiveness of the pressure detector 104 includes:

[0037] The DCU control unit 2 determines the effectiveness of the pressure detector 104 by reading the pressure values of the air solenoid valve 108 in the closed and open states, and measures the pressure value change when the solenoid valve is open and closed, requiring the change to be greater than 0.5 bar.

[0038] The DCU control unit 2 determines the accuracy of the zero point position by reading the data of the pressure detector 104 when the solenoid valve is closed. When the zero point position offset of the pressure detector 104 is within 10%, the DCU controller can perform compensation correction.

[0039] Furthermore, the pressure detection method further includes a step (step 302 ) in which the DCU control unit 2 determines the effectiveness of the air solenoid valve 108 by reading the pressure values of the air solenoid valve 108 in the closed and open states.

[0040] The determination of the effectiveness of the air solenoid valve 108 includes:

[0041] When the air solenoid valve 108 is in the closed state, if the output data of the pressure detector 104 collected by the DCU control unit 2 is greater than 2 bar, it is determined that the solenoid valve closure fails;

[0042] When the air solenoid valve 108 is in the open state, when the pressure value collected by the DCU control unit 2 is close to the zero pressure value, it is determined that the solenoid valve fails to open.

[0043] When the pressure detector 104 and the air solenoid valve 108 are valid, the DCU control unit 2 compares the collected data of the pressure detector 104 with the target pressure range (step 303);

[0044] When the measured pressure is greater than the target range, the DCU control unit 2 stops the urea supply pump 107 and issues a pipeline blockage alarm;

[0045] When the measured pressure is lower than the target range, the DCU control unit 2 stops the urea supply pump 107 and issues a low pressure fault alarm.

[0046] The above embodiments are only used to illustrate the essence of the present invention, but do not limit the present invention. Without departing from the principle of the present invention, any modification, simplification or other replacement methods are included in the protection scope of the present invention.

[0047] The parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

Claims

1. A post-processing liquid supply pipeline pressure detection device, comprising a post-processing supply module, a DCU control unit, a gas-assisted device, a pressure detector and a nozzle, characterized in that: The post-treatment supply module includes a urea supply pump, and the gas-assisted device includes an air source and an air solenoid valve. The pressure liquid generated by the urea supply pump and the high-pressure gas generated by the air source merge into a mixing chamber, and the generated gas-liquid multiphase fluid is output through a nozzle. The pressure detector includes a package, through which the pressure detector is installed on the gas flow channel and connected in series between the mixing chamber and the air solenoid valve. The detection port of the pressure detector is directly located in the flow channel without infinite hole interference. The pressure detector is used to detect the gas pressure at the front end of the air solenoid valve and feed the pressure information back to the DCU control unit. The DCU control unit determines the effectiveness of the pressure detector by reading the pressure values of the air solenoid valve in the closed and open states, and makes judgments based on the change in the measured pressure value when the solenoid valve is open and closed, requiring the change to be greater than 0.5 bar; The DCU control unit determines the effectiveness of the air solenoid valve by reading the pressure values when the air solenoid valve is closed and open.

2. The post-processing pipeline pressure detection device according to claim 1, characterized in that: The pressure detector is a pressure sensor.

3. A post-processing liquid supply pipeline pressure detection method, characterized in that: The post-processing liquid supply pipeline pressure detection device according to any one of claims 1-2 is used. The DCU control unit determines the accuracy of the zero point position by reading the pressure detector data when the air solenoid valve is closed. When the zero point position offset of the pressure detector is within 10%, the DCU controller performs compensation correction.

4. The post-processing liquid supply pipeline pressure detection method according to claim 3, characterized in that: The DCU reads the pressure detector data. When the air solenoid valve is in the closed state, the detection data is greater than 2 bar, and the closing is judged to be failed; when the air solenoid valve is in the open state, the detection data is close to the zero pressure value, and the opening is judged to be failed.

5. The post-processing liquid supply pipeline pressure detection method according to claim 4, characterized in that: The following steps are also included: The working range of the pressure detector is set according to the gas source pressure, and the DCU pre-stores the pressure characteristic parameters of the pressure detector; The DCU control unit presets a target pressure range value according to the gas pressure required by the post-processing supply module.

6. The post-processing liquid supply pipeline pressure detection method according to claim 5, characterized in that: The method comprises the steps of comparing the collected pressure detector data with the target pressure range by the DCU control unit.

7. The post-processing liquid supply pipeline pressure detection method according to claim 6, characterized in that: When the pressure detector data collected by the DCU is greater than the target pressure range, a pipeline blockage alarm is given; when the pressure detector data collected by the DCU is less than the target pressure range, a low pressure fault alarm is given.

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