Method and device for metering a liquid for a metering unit of a vehicle

Abstract

This invention discloses a method and apparatus for measuring liquids in a vehicle's metering unit. The method includes: detecting a valve opening current value during the opening process of a solenoid valve in the metering unit; determining the liquid pressure across the solenoid valve based on the valve opening current value; and determining a liquid metering value based on the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit via the solenoid valve within a predetermined time period. According to the method and apparatus for measuring liquids in a vehicle's metering unit of this invention, the amount of liquid can be measured by detecting the valve opening current value of the solenoid valve in the metering unit, thereby enabling accurate determination of the amount of liquid entering the metering unit without the need for a pressure sensor within the metering unit, thus reducing the cost of the vehicle's metering unit.

Description

Technical Field

[0001] This invention relates to the field of metrology, and in particular, to a method and apparatus for measuring liquids in a metering unit for vehicles. Background Technology

[0002] In vehicles, some systems (such as hydrocarbon injection systems (HCI), urea injection systems (DeNOx), or other systems) require precise metering of the amount of liquids (such as urea, fuel oil (such as diesel)) entering the system in order to enable the system to perform its functions.

[0003] Typically, these systems in a vehicle measure liquids using pressure sensors in the system's metering unit (e.g., the MU (metering unit) in an HCI system, or the DM (dosing module) in a DeNOx system). However, pressure sensors are generally expensive, resulting in a high cost for the vehicle's metering unit.

[0004] Therefore, there is a need for a measurement method that can accurately measure liquids and save on the cost of metering units. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for metering liquids in a metering unit for vehicles.

[0006] According to one aspect of the present invention, a method for metering liquid in a metering unit for a vehicle is provided, the method comprising: detecting a valve opening current value during the opening process of a solenoid valve of the metering unit; determining a liquid pressure borne by the solenoid valve based on the valve opening current value; and determining a liquid metering value based on the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit via the solenoid valve within a predetermined time.

[0007] According to another aspect of the present invention, an apparatus for metering liquid in a metering unit for a vehicle is provided, the apparatus comprising: a detection unit configured to detect a valve opening current value during the opening process of a solenoid valve of the metering unit; a first determination unit configured to determine a liquid pressure borne by the solenoid valve based on the valve opening current value; and a second determination unit configured to determine a liquid metering value based on the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit via the solenoid valve within a predetermined time.

[0008] According to another aspect of the present invention, a computer program product is provided, wherein the computer program product includes a computer program that, when executed by a processor, causes the processor to implement a method for metering liquids for a vehicle according to the present invention.

[0009] According to the method and apparatus for measuring liquids in a metering unit for a vehicle of the present invention, the amount of liquid can be measured by detecting the valve opening current value of the solenoid valve of the metering unit, thereby enabling accurate determination of the amount of liquid entering the metering unit without the need to install a pressure sensor in the metering unit, thus reducing the cost of the metering unit for the vehicle. Attached Figure Description

[0010] The foregoing and other aspects of the invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, including: Figure 1 A flowchart is shown of a method for metering liquids using a metering unit for a vehicle according to an exemplary embodiment of the present invention.

[0011] Figure 2 An example of a valve opening current value according to an exemplary embodiment of the present invention is shown.

[0012] Figure 3 A flowchart illustrating the step of determining liquid pressure in a method for metering liquid in a metering unit for a vehicle according to an exemplary embodiment of the present invention is shown.

[0013] Figure 4 A flowchart of a method for metering liquids using a metering unit for a vehicle according to another exemplary embodiment of the present invention is shown.

[0014] Figure 5 A block diagram of a device for metering liquids for a vehicle, according to an exemplary embodiment of the present invention, is shown. Detailed Implementation

[0015] Hereinafter, some exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings in order to better understand the basic ideas and advantages of the present invention.

[0016] Figure 1 A flowchart is shown of a method for metering liquids using a metering unit for a vehicle according to an exemplary embodiment of the present invention.

[0017] Reference Figure 1 In step S1, the valve opening current value is detected during the opening process of the solenoid valve in the metering unit.

[0018] The metering unit here can be any metering unit in a vehicle system that requires the metering of liquids. For example, the metering unit can be the metering unit (MU) in a vehicle's hydrocarbon injection system (HCI), the metering module (DM) in a urea injection system (DeNOx), etc.

[0019] As an example, the solenoid valve of the metering unit can be an ETI valve (electromagnetically controlled injection valve). In this case, the valve opening current value can be the inflection point current value of the current characteristic curve of the current flowing through the ETI valve during the opening process of the ETI valve.

[0020] Figure 2 An example of a valve opening current value according to an exemplary embodiment of the present invention is shown.

[0021] Figure 2 The diagram shows the current characteristic curve of the current flowing through the ETI valve during the process of applying voltage to the ETI valve to open it. Figure 2 In the diagram, the horizontal axis represents time t in milliseconds (ms), and the vertical axis represents the current i flowing through the ETI valve in amperes (A). The valve opening current value is... Figure 2 The inflection point current value of the first inflection point on the left side of the curve, that is, the current value at the position marked by the circular dot on the curve.

[0022] It should be understood that Figure 2 This is just one example of the current characteristic curve and valve opening current value during the solenoid valve opening process. Depending on the actual solenoid valve used, the current characteristic curve and valve opening current value during the solenoid valve opening process may differ from the provided example. Figure 2 different.

[0023] Return to reference Figure 1 In step S2, the liquid pressure that the solenoid valve withstands is determined based on the valve opening current value.

[0024] For example, in step S2, the liquid pressure that the solenoid valve can withstand can be determined based on the valve opening current value and the structural parameters of the solenoid valve.

[0025] Figure 3 A flowchart of step S2, determining liquid pressure, is shown in a method for metering liquid in a metering unit for a vehicle according to an exemplary embodiment of the present invention.

[0026] Reference Figure 3 In step S21, the electromagnetic force used to open the solenoid valve can be determined based on the valve opening current value and the first structural parameters of the solenoid valve.

[0027] For example, the first structural parameter of the solenoid valve may include at least one of the following: the number of turns of the solenoid valve coil, the magnetic constant of the solenoid valve, the cross-sectional area of ​​the solenoid valve coil, and the distance between the armature and the electromagnet of the solenoid valve.

[0028] As an example, the electromagnetic force can be determined in step S21 by the following equation (1): (1) In equation (1), The electromagnetic force used to open the solenoid valve, This is a temperature correction factor. This refers to the actual ambient temperature. To preset the ambient temperature, This refers to the number of turns of the solenoid valve's coil. This is the valve opening current value. Let be the magnetic constant of the solenoid valve. Let be the cross-sectional area of ​​the solenoid valve coil. This is the distance between the armature and the electromagnet of the solenoid valve.

[0029] For example, the magnetic constant m of a solenoid valve can be a constant 4π × 10⁻⁶. -7 Given that the solenoid valve material is 430FR and the preset operating temperature (preset ambient temperature) is room temperature (25℃), the temperature correction factor is... The value range can be [0.0014%, 0.0032%].

[0030] In step S21, the electromagnetic force for opening the solenoid valve is determined. Then, in step S22, the liquid pressure that the solenoid valve can withstand can be determined based on the electromagnetic force and the second structural parameters of the solenoid valve.

[0031] For example, the second structural parameters of the solenoid valve may include at least one of the following: the spring force and friction force of the solenoid valve during the opening process, the valve seat area of ​​the solenoid valve, and the valve orifice area of ​​the solenoid valve for allowing liquid to flow through.

[0032] As an example, the liquid pressure can be determined in step S22 by the following equation (2): (2) In equation (2), The pressure of the liquid. The electromagnetic force, The spring force and friction force of the solenoid valve during the opening process are considered. This represents the valve seat area of ​​the solenoid valve.

[0033] It should be understood that This corresponds to the electromagnetic force during the opening process of the solenoid valve. The force that is overcome, therefore, It may also include other forces besides the spring force and friction force mentioned above.

[0034] Return to reference Figure 1After determining the liquid pressure borne by the solenoid valve in step S2, in step S3, the liquid metering value is determined according to the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit through the solenoid valve within a predetermined time.

[0035] For example, the predetermined time here can refer to a unit of time, so the liquid metering value can represent the amount of liquid that can enter the metering unit through the solenoid valve per unit time. In addition, the predetermined time here can also represent other times according to actual needs, such as the duration for which the solenoid valve can or needs to remain open after each opening.

[0036] In step S2, the liquid pressure that the solenoid valve withstands is determined by the above equation (2). In this case, as an example, the liquid metering value can be determined in step S3 by the following equation (3): (3) In equation (3), For liquid measurement values, This refers to the orifice area of ​​the solenoid valve, which is the valve hole through which the liquid flows. The density of the liquid flowing through the solenoid valve. The predetermined time.

[0037] Here, if the duration for which the solenoid valve needs to remain open after each opening corresponds to the predetermined time, the liquid metering value determined in step S3 is the amount of liquid that can enter the metering unit through the solenoid valve after each opening.

[0038] When the predetermined time is a unit of time, in order to allow the expected amount of liquid to enter the metering unit via the solenoid valve, the method for metering liquid in the metering unit of the present invention may further include the following steps: determining the opening duration for which the solenoid valve needs to remain open based on the liquid metering value and the expected amount of liquid to enter the metering unit, so that the expected amount of liquid can enter the metering unit via the solenoid valve (S4, ...). Figure 1 (Not shown).

[0039] Furthermore, in order to make the liquid measurement more accurate, the method for measuring liquid in the metering unit for a vehicle according to the present invention can also determine whether the actual amount of liquid entering the metering unit during the start duration of the solenoid valve meets the expected amount of liquid, and adjust the liquid measurement when it does not meet the expected amount of liquid, thereby making the liquid measurement more accurate.

[0040] Figure 4 A flowchart of a method for metering liquids using a metering unit for a vehicle according to another exemplary embodiment of the present invention is shown.

[0041] Reference Figure 4 , Figure 4 Steps S1 to S3 are the same as above. Figures 1 to 3 The steps described are the same. Figure 4 Step S4 is the step described above: Based on the liquid metering value and the expected liquid volume that needs to enter the metering unit, determine the opening duration for which the solenoid valve needs to remain open, so that the expected liquid volume can enter the metering unit through the solenoid valve.

[0042] After the solenoid valve remains open for the duration determined in step S4, and then changes from the open state to the closed state, step S5 can be executed: determine whether the actual amount of liquid entering the metering unit through the solenoid valve during the current opening duration of the solenoid valve is equal to the expected amount of liquid (step S5 is described in detail below).

[0043] In the case where the actual liquid volume is not equal to the expected liquid volume ( Figure 4 For “N” in the equation above, step S6 can be executed: adjust the temperature correction coefficient in equation (1) above. Adjustments are made so that the actual amount of liquid entering the metering unit during the subsequent opening duration of the solenoid valve is equal to the expected amount of liquid.

[0044] Here, if the actual liquid volume is not equal to the expected liquid volume, it indicates that the liquid measurement value determined in step S3 is not accurate enough. Therefore, the accuracy can be improved by adjusting the parameters used to determine the liquid measurement value, such as the temperature correction factor. This is to make the determined liquid measurement values ​​more accurate.

[0045] For example, in the above example of the solenoid valve, the temperature correction factor can be adjusted within the range of [0.0014%, 0.0032%]. Adjustments will be made.

[0046] When the actual liquid volume equals the expected liquid volume ( Figure 4 The "Y" in the figure allows the previous temperature correction factor to be used the next time the solenoid valve is opened to measure the liquid. To determine the liquid measurement value.

[0047] The above method of determining the liquid metering value by detecting the valve opening current value of the solenoid valve of the metering unit enables the metering unit to accurately measure the liquid without the need to install a pressure sensor for liquid metering.

[0048] The above steps S5 and S6 will be described in detail below with reference to two embodiments: the metering unit (DM) in the vehicle's urea injection system (DeNOX) and the metering unit (MU) in the vehicle's hydrocarbon injection system (HCI).

[0049] In one embodiment, as an example, the metering unit may be a metering unit in a vehicle's urea injection system, the liquid may be urea, and the expected liquid volume may be the expected urea volume.

[0050] In this scenario, after the vehicle is started, the solenoid valve of the metering unit needs to be periodically opened to allow the expected amount of urea to enter the metering unit periodically (e.g., every 1 minute). That is, during vehicle operation, the solenoid valve of the metering unit is periodically opened so that the expected amount of urea enters the metering unit via the solenoid valve during the opening duration of each cycle, and the above operation ends after the vehicle is turned off.

[0051] Therefore, when the solenoid valve is opened in each cycle, the step of detecting the valve opening current value during the opening process of the solenoid valve (S1) is started, and then the subsequent steps can be executed.

[0052] in this case, Figure 4 Step S5 may include the following steps: at the end of each cycle, detecting the amount of nitrogen-containing ions in the gas discharged from the urea injection system and determining whether the amount of ions is less than a predetermined ion threshold; if the amount of ions is determined to be not less than the predetermined ion threshold, determining that the actual amount of urea in the current cycle is not equal to the expected amount of urea; if the amount of ions is determined to be less than the predetermined ion threshold, determining that the actual amount of urea in the current cycle is equal to the expected amount of urea.

[0053] Here, since the urea entering the metering unit of the urea injection system needs to be completely converted into nitrogen and water at high temperature, when the actual amount of urea entering the metering unit does not match the expected amount of urea, the amount of nitrogen-containing ions in the gas discharged from the urea injection system will be greater than or equal to the predetermined ion threshold. Therefore, step S5 can determine whether the actual amount of urea entering the metering unit is equal to the expected amount of urea by detecting the amount of nitrogen-containing ions in the gas discharged from the urea injection system.

[0054] For example, the amount of nitrogen-containing ions in the gas discharged from the urea injection system can be detected by a NOx sensor in the gas discharge section of the urea injection system.

[0055] Subsequently, if it is determined that the actual amount of urea is not equal to the expected amount of urea, the temperature correction factor can be adjusted. Adjustments are made so that the actual amount of urea entering the metering unit in subsequent cycles is equal to the expected amount of urea (S6).

[0056] As an example, the temperature correction factor can be adjusted as follows: : First, adjust the temperature correction factor by either increasing or decreasing it (e.g., by increasing). Adjustments are made to use the adjusted temperature correction factor in the next cycle of the current cycle. A defined liquid measurement value.

[0057] Then, at the end of the next week, it is determined whether the amount of ions corresponding to the next cycle is lower or higher than that of the current cycle.

[0058] Here, the temperature correction factor can be determined by judging whether the amount of ions detected in the next cycle decreases or increases compared to the current cycle. Is the method of adjustment correct?

[0059] Subsequently, if the temperature decrease is confirmed (indicating that the above method of adjusting the temperature coefficient is correct), continue adjusting the temperature correction coefficient in the same manner in subsequent cycles. Adjustments are made until the amount of the corresponding ions detected in the corresponding cycle is less than the predetermined ion threshold.

[0060] If an increase is confirmed (indicating that the above method of adjusting the temperature coefficient is incorrect), the temperature correction coefficient should be adjusted in subsequent cycles using either increasing or decreasing methods (e.g., decreasing). Adjustments are made until the amount of the corresponding ions detected in the corresponding cycle is less than the predetermined ion threshold.

[0061] By periodically determining the amount of liquid (liquid metering value) that can enter the metering unit through the solenoid valve within a predetermined time in each cycle using the above method, it is possible to ensure accurate metering of the urea entering the metering unit.

[0062] In another embodiment, the metering unit may be a metering unit in the vehicle's hydrocarbon injection system, wherein the liquid is the vehicle's operating oil, such as diesel, and the expected liquid quantity is the expected oil quantity.

[0063] In this case, when it is determined that the hydrocarbon injection system needs to be cleaned, the solenoid valve of the metering unit is opened so that the expected amount of oil (the oil to be used) enters the metering unit through the solenoid valve during the opening duration of the solenoid valve during the cleaning process.

[0064] For example, if a predetermined time has elapsed since the last cleaning of the hydrocarbon injection system (e.g., 6000 hours), and / or if the pressure difference between the inlet and outlet of the gas discharge section of the hydrocarbon injection system (e.g., DPF (particulate filter)) is greater than the cleaning pressure difference threshold (e.g., 100 mP), it can be determined that the hydrocarbon injection system needs to be cleaned. In this case, the solenoid valve of the metering unit can be opened to allow the expected amount of working oil to enter the metering unit for cleaning the hydrocarbon injection system.

[0065] As an example, the valve opening current value (S1) during the opening process of the solenoid valve can be detected each time the solenoid valve is opened, and then subsequent steps can be executed.

[0066] In this case, step S5 may include the following steps: at the end of the current cleaning of the hydrocarbon injection system, detect the pressure difference between the inlet and outlet of the particulate filter (DPF) of the hydrocarbon injection system, and determine whether the pressure difference is less than a predetermined pressure difference threshold. If the pressure difference is determined to be less than the predetermined pressure difference threshold, determine that the actual oil volume is equal to the expected oil volume. If the pressure difference is determined to be not less than the predetermined pressure difference threshold, determine that the actual oil volume is less than the expected oil volume.

[0067] Typically, cleaning a hydrocarbon injection system involves cleaning the particulate filter (DPF). Therefore, it can be determined whether the particulate filter has been adequately cleaned, i.e., whether a sufficient amount (expected amount) of fuel, such as diesel, has been injected into the metering unit, by detecting the pressure difference between the inlet and outlet of the particulate filter.

[0068] For example, the predetermined pressure difference threshold here can be less than the cleaning pressure difference threshold used to determine the need to clean the hydrocarbon injection system, for example, the predetermined pressure difference threshold here can be 50 mP.

[0069] It should be understood that the above cleaning pressure threshold and predetermined pressure difference threshold are only examples, and can be set to other values ​​according to actual needs.

[0070] Subsequently, if it is determined that the actual oil quantity is less than the expected oil quantity, the temperature correction factor can be adjusted. Adjustments are made so that the actual amount of oil used that actually enters the metering unit during subsequent cleaning is equal to the expected amount of oil (S6).

[0071] As an example, the temperature correction factor can be increased. This continues until the pressure difference detected at the end of a subsequent cleaning cycle is less than the predetermined pressure difference threshold.

[0072] In this way, the liquid metering value calculated during subsequent cleaning can be reduced, thereby increasing the actual amount of liquid that can enter the metering unit, i.e., the amount of oil used, thus improving the accuracy of liquid metering during cleaning.

[0073] According to the method for measuring liquids in a metering unit for vehicles of the present invention, the amount of liquid can be measured by detecting the valve opening current value of the solenoid valve of the metering unit, thereby enabling accurate determination of the amount of liquid entering the metering unit without the need to install a pressure sensor in the metering unit, thus reducing the cost of the metering unit for vehicles.

[0074] Figure 5 A block diagram of a device for metering liquids for a vehicle, according to an exemplary embodiment of the present invention, is shown.

[0075] Reference Figure 5 The device for measuring liquids in a metering unit for a vehicle according to the present invention includes: a detection unit 1, a first determining unit 2, and a second determining unit 3.

[0076] The detection unit 1 is configured to detect the valve opening current value during the opening process of the solenoid valve in the metering unit.

[0077] The first determination unit 2 is configured to determine the liquid pressure that the solenoid valve is subjected to based on the valve opening current value.

[0078] The second determining unit 3 is configured to determine a liquid metering value based on the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit via the solenoid valve within a predetermined time.

[0079] The above has been referred to Figures 1 to 4 The determination of valve opening current, liquid pressure, and liquid metering value has been described in detail, and will not be repeated here.

[0080] According to the present invention, a device for measuring liquid in a metering unit for a vehicle can measure the amount of liquid by detecting the valve opening current value of the solenoid valve of the metering unit, thereby enabling accurate determination of the amount of liquid entering the metering unit without the need to install a pressure sensor in the metering unit, thus reducing the cost of the metering unit for the vehicle.

[0081] An exemplary embodiment of the present invention also provides a computer program product, wherein the computer program product includes a computer program, which, when executed by a processor, causes the processor to implement a method for metering liquids according to the present invention for a metering unit for a vehicle. The computer program product may include computer programs, program code, instructions, or combinations thereof for independently or jointly commanding or configuring hardware devices to operate as needed. The computer program and / or program code may include programs or computer-readable instructions, software components, software modules, data files, data structures, etc., implementable by one or more hardware devices. Examples of program code may include machine code generated by a compiler and higher-level program code executed using an interpreter.

[0082] Furthermore, the various units in the above-described apparatus and device according to exemplary embodiments of the present invention can be implemented as hardware components or software modules. Additionally, those skilled in the art can implement each unit, for example, using a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or a processor, depending on the processing performed by each defined unit.

[0083] Although the invention has been described and illustrated herein with reference to specific embodiments, the invention is not limited to the details shown. Rather, various modifications to these details can be made within the scope of the invention.

[0084] List of reference numerals S1 detects the valve opening current during the opening process of the solenoid valve in the metering unit. S2 determines the liquid pressure that the solenoid valve withstands based on the valve opening current value. S3 determines the liquid metering value based on the liquid pressure. S4 determines the duration for which the solenoid valve needs to remain open, based on the liquid metering value and the expected volume of liquid to enter the metering unit. S5 determines whether the actual amount of liquid entering the metering unit via the solenoid valve during the current opening duration of the solenoid valve is equal to the expected amount of liquid. S6 Temperature Correction Factor Make adjustments Y is N No S21 Determine the electromagnetic force used to open the solenoid valve based on the valve opening current value and the first structural parameters of the solenoid valve. S22 determines the liquid pressure that the solenoid valve withstands based on the electromagnetic force and the second structural parameters of the solenoid valve. t [ms] Time (milliseconds) i [A] Current (Amperes) 1 detection unit 2 First Determined Unit 3 Second Determining Unit

Claims

1. A method for metering liquids in a metering unit for a vehicle, the method comprising: The valve opening current value (S1) is detected during the opening process of the solenoid valve in the metering unit. The liquid pressure (S2) that the solenoid valve withstands is determined based on the valve opening current value. The liquid metering value is determined based on the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit via the solenoid valve within a predetermined time (S3).

2. The method according to claim 1, wherein, The method further includes: determining the opening duration for which the solenoid valve needs to remain open based on the liquid metering value and the expected liquid volume to enter the metering unit, so that the expected liquid volume can enter the metering unit via the solenoid valve (S4); and / or The solenoid valve is an ETI valve, and the valve opening current value is the inflection point current value of the current characteristic curve of the current flowing through the ETI valve during the opening process of the ETI valve.

3. The method according to claim 2, wherein, The steps for determining the liquid pressure that the solenoid valve can withstand based on the valve opening current value include: Based on the valve opening current value and the first structural parameters of the solenoid valve, determine the electromagnetic force (S21) used to open the solenoid valve. Based on the electromagnetic force and the second structural parameters of the solenoid valve, the liquid pressure that the solenoid valve withstands is determined (S22).

4. The method according to claim 3, wherein, The electromagnetic force (S21) is determined by the following equation: in, The electromagnetic force, This is the temperature correction factor. This refers to the actual ambient temperature. To preset the ambient temperature, This refers to the number of turns of the solenoid valve's coil. This is the valve opening current value. Let be the magnetic constant of the solenoid valve. Let be the cross-sectional area of ​​the solenoid valve coil. This is the distance between the armature and the electromagnet of the solenoid valve.

5. The method according to claim 3 or 4, wherein, The liquid pressure (S22) is determined by the following equation: in, The pressure of the liquid. The electromagnetic force, The spring force and friction force of the solenoid valve during the opening process are considered. This represents the valve seat area of ​​the solenoid valve.

6. The method according to claim 3 or 4, wherein, The liquid measurement value (S3) is determined by the following equation: in, For liquid measurement values, This refers to the orifice area of ​​the solenoid valve, which is the valve orifice through which the liquid flows. The pressure of the liquid. The density of the liquid flowing through the solenoid valve. The predetermined time.

7. The method according to claim 4, wherein, The method further includes: After the solenoid valve changes from the open state to the closed state, it is determined whether the actual amount of liquid entering the metering unit through the solenoid valve during the current opening duration of the solenoid valve is equal to the expected amount of liquid (S5). When the actual liquid volume does not equal the expected liquid volume, the temperature correction factor is adjusted. Adjustments are made so that the actual amount of liquid entering the metering unit during the subsequent opening duration of the solenoid valve is equal to the expected amount of liquid (S6).

8. The method according to claim 7, wherein, The metering unit is the metering unit in the vehicle's urea injection system, the liquid is urea, and the expected liquid volume is the expected urea volume. During vehicle operation, the solenoid valve of the metering unit is periodically opened so that the expected amount of urea enters the metering unit via the solenoid valve during the opening duration of each cycle. Specifically, when the solenoid valve is opened in each cycle, the valve opening current value during the opening process is detected. The step (S5) of determining whether the actual amount of liquid entering the metering unit through the solenoid valve during the current opening duration of the solenoid valve after the solenoid valve changes from the open state to the closed state includes: At the end of each cycle, the amount of nitrogen-containing ions in the gas discharged from the urea injection system is detected, and it is determined whether the amount of ions is less than a predetermined ion threshold. If it is determined that the amount of ions is not less than the predetermined ion threshold, it is determined that the actual amount of urea in the current cycle is not equal to the expected amount of urea. If the amount of ions is determined to be less than the predetermined ion threshold, the actual amount of urea in the current cycle is determined to be equal to the expected amount of urea.

9. The method according to claim 8, wherein, Temperature correction factor The step (S6) of adjusting the liquid flow so that the actual amount of liquid entering the metering unit during the subsequent opening duration of the solenoid valve is equal to the expected amount of liquid includes: Adjust the temperature correction factor by either increasing or decreasing it. Adjustments are made to use the adjusted temperature correction factor in the next cycle of the current cycle. Determined liquid measurement value, At the end of the next cycle, it is determined whether the amount of ions corresponding to the next cycle has decreased or increased relative to the current cycle. If a reduction is determined, the temperature correction factor shall continue to be adjusted in the manner described in subsequent cycles. Adjustments are made until the amount of the corresponding ions detected in the corresponding cycle is less than the predetermined ion threshold. If an increase is confirmed, the temperature correction factor is adjusted in another manner, either by increasing or decreasing, in subsequent cycles. Adjustments are made until the amount of the corresponding ions detected in the corresponding cycle is less than the predetermined ion threshold.

10. The method according to claim 9, wherein, The metering unit is the metering unit in the vehicle's hydrocarbon injection system, the liquid is the vehicle's fuel oil, and the expected liquid quantity is the expected fuel quantity. When it is determined that the hydrocarbon injection system needs cleaning, the solenoid valve of the metering unit is opened so that the expected amount of oil to be used enters the metering unit via the solenoid valve during the opening duration of the solenoid valve during cleaning. Each time the solenoid valve is opened, the valve opening current value during the opening process is detected. The step (S5) of determining whether the actual amount of liquid entering the metering unit through the solenoid valve during the current opening duration of the solenoid valve after the solenoid valve changes from the open state to the closed state includes: At the end of the current cleaning cycle of the hydrocarbon injection system, the pressure difference between the inlet and outlet of the particulate filter of the hydrocarbon injection system is detected, and it is determined whether the pressure difference is less than a predetermined pressure difference threshold. If the pressure difference is determined to be less than a predetermined pressure difference threshold, then the actual oil volume is determined to be equal to the expected oil volume. If the pressure difference is determined to be not less than a predetermined pressure difference threshold, then the actual oil volume is determined to be less than the expected oil volume.

11. The method according to claim 10, wherein, Temperature correction factor The step (S6) of adjusting the liquid flow so that the actual amount of liquid entering the metering unit during the subsequent opening duration of the solenoid valve is equal to the expected amount of liquid includes: Increase the temperature correction factor This continues until the pressure difference detected at the end of a subsequent cleaning cycle is less than the predetermined pressure difference threshold.

12. A device for metering liquids in a metering unit for a vehicle, the device comprising: The detection unit is configured to detect the valve opening current value during the opening process of the solenoid valve in the metering unit. The first determining unit is configured to determine the liquid pressure borne by the solenoid valve based on the valve opening current value. The second determining unit is configured to determine a liquid metering value based on the liquid pressure, wherein the liquid metering value represents the amount of liquid that can enter the metering unit via a solenoid valve within a predetermined time.

13. A computer program product, wherein, The computer program product includes a computer program that, when executed by a processor, causes the processor to perform the method according to any one of claims 1 to 12.

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