Method for correcting flow rate of differential pressure flowmeter, correction device, and management system

Abstract

The application provides a correction method, a correction device and a management system for the flow of a differential pressure flowmeter, the differential pressure flowmeter comprising a differential pressure sensor and a throttling element, an EGR valve being located on an exhaust pipeline of an engine and on one side of the differential pressure flowmeter, the method comprising: determining a correlation formula of a differential pressure value of the differential pressure sensor and an opening value of the EGR valve; obtaining a plurality of opening values and corresponding differential pressure values; processing the correlation formula by using a least square method to obtain a variance function, and substituting the plurality of opening values and the corresponding differential pressure values into the variance function to obtain an optimal offset value; in the case that the optimal offset value is less than or equal to an offset threshold value, obtaining a differential pressure value of the differential pressure sensor to obtain a current differential pressure value, calculating a difference value between the current differential pressure value and the optimal offset value to obtain a corrected differential pressure value; and determining the flow of the exhaust pipeline according to the corrected differential pressure value. The method solves the problem that the flow measurement is inaccurate due to the zero drift of the differential pressure sensor in the prior art.

Description

Technical Field

[0001] This invention relates to the field of engine control technology, and more specifically, to a method, device, computer-readable storage medium, and management system for correcting the flow rate of a differential pressure flow meter. Background Technology

[0002] Differential pressure sensors are prone to zero-point drift due to changes in operating conditions, requiring periodic zero-point learning. Therefore, it's essential to determine if zero-point drift exists in the current sensor. Existing zero-point drift diagnostic strategies typically learn a deviation voltage as the zero point when the engine is off and the EGR valve is closed (zero flow). However, zero-point drift is often caused by differences in environmental factors (temperature, pressure, etc.) and the sensor's inherent characteristics during use. Therefore, drift diagnosis during operation is crucial, but current technology cannot perform this diagnosis during use. Summary of the Invention

[0003] The main objective of this application is to provide a method, device, computer-readable storage medium, and management system for correcting the flow rate of a differential pressure flow meter, so as to at least solve the problem of inaccurate flow measurement caused by zero-point drift of differential pressure sensors in the prior art.

[0004] To achieve the above objectives, according to one aspect of this application, a method for correcting the flow rate of a differential pressure flow meter is provided. The differential pressure flow meter includes a differential pressure sensor and a throttling element. The throttling element is located on the exhaust pipe of an engine, and the cross-sectional area of ​​the throttling element is smaller than the cross-sectional area of ​​the exhaust pipe. The differential pressure sensor is used to monitor the pressure difference between the pipe segment where the throttling element is located and other pipe segments in the exhaust pipe to determine the flow rate. An EGR valve is located on the exhaust pipe of the engine and on one side of the differential pressure flow meter. The method includes: determining a correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve, wherein the correlation formula is that the differential pressure value is equal to the product of the opening value and a proportional coefficient plus an offset value; acquiring multiple... The opening value and the corresponding differential pressure value are respectively, with a one-to-one correspondence between the opening value and the differential pressure value. The least squares method is used to process the correlation formula to obtain a variance function, which is a function that calculates the variance of both sides of the mathematical expression of the correlation formula. Multiple opening values ​​and corresponding differential pressure values ​​are substituted into the variance function to calculate the optimal offset value, which is the offset value corresponding to the minimum function value of the variance function. If the optimal offset value is less than or equal to the offset threshold, the differential pressure value of the differential pressure sensor is obtained to obtain the current differential pressure value. The difference between the current differential pressure value and the optimal offset value is calculated to obtain a corrected differential pressure value. The flow rate of the exhaust pipeline is determined based on the corrected differential pressure value.

[0005] Optionally, before acquiring multiple opening values ​​and corresponding differential pressure values, the method further includes: acquiring engine operating condition data, the operating condition data including fuel injection quantity, engine speed, and engine temperature; determining whether each operating condition data meets a corresponding preset requirement, the preset requirement including the fuel injection quantity being greater than or equal to a fuel injection quantity threshold, the engine speed being greater than or equal to a speed threshold, and the engine temperature being within a predetermined temperature range; if any of the operating condition data fails to meet the corresponding preset requirement, continuing to acquire the operating condition data until all the operating condition data meet the corresponding preset requirement.

[0006] Optionally, obtaining multiple opening values ​​and corresponding differential pressure values ​​includes: controlling the EGR valve to adjust the opening value within the opening range and obtaining the corresponding differential pressure value, thereby obtaining multiple opening values ​​and corresponding differential pressure values, wherein the opening range is the range of the opening values ​​corresponding to the EGR valve when the engine temperature is within a predetermined temperature range.

[0007] Optionally, substituting multiple opening values ​​and corresponding pressure difference values ​​into the variance function to calculate the optimal offset value includes: using the partial derivative method to find the partial derivative of the proportional coefficient with respect to the expression of the variance function to obtain a first partial derivative function; using the partial derivative method to find the partial derivative of the offset value with respect to the expression of the variance function to obtain a second partial derivative function; and calculating the offset value corresponding to the case where both the first and second partial derivative functions are equal to 0 to obtain the optimal offset value.

[0008] Optionally, calculating the offset value corresponding to the case where both the first partial derivative function and the second partial derivative function are equal to 0, to obtain the optimal offset value, includes: simultaneously performing elimination calculations when both the first partial derivative function and the second partial derivative function are equal to 0, to obtain an offset value relationship and a proportional coefficient relationship, wherein the offset value relationship does not contain the proportional coefficient, and the proportional coefficient relationship does not contain the offset value; calculating the average value of all the opening values ​​and the average value of all the pressure difference values, respectively, to obtain the average opening value and the average pressure difference value; substituting multiple opening values, multiple pressure difference values, the average opening value, and the average pressure difference value into the proportional coefficient relationship to calculate the optimal proportional coefficient; and substituting the optimal proportional coefficient, the average opening value, and the average pressure difference value into the offset value relationship to calculate the optimal offset value.

[0009] Optionally, after substituting multiple opening values ​​and corresponding differential pressure values ​​into the variance function to calculate the optimal offset value, the method further includes: if the optimal offset value is greater than the offset threshold, controlling the issuance of a first fault alarm, the first fault alarm being used to indicate that the differential pressure flow meter has a zero-point drift fault.

[0010] Optionally, after determining the flow rate of the exhaust pipe based on the corrected differential pressure value, the method further includes: obtaining the theoretical value of the exhaust gas flow rate corresponding to the corrected differential pressure value by querying an exhaust gas flow rate lookup table based on the corrected differential pressure value, wherein the exhaust gas flow rate lookup table is a lookup table of the differential pressure value, the opening value, and the theoretical value of the exhaust gas flow rate; issuing a second fault alarm when the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is greater than an error threshold, wherein the second fault alarm is used to remind the differential pressure flow meter of any fault other than zero-point drift; and determining that the differential pressure flow meter is fault-free when the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is less than or equal to the error threshold.

[0011] According to another aspect of this application, a flow correction device for a differential pressure flow meter is provided. The differential pressure flow meter includes a differential pressure sensor and a throttling element. The throttling element is located on the exhaust pipe of an engine, and the cross-sectional area of ​​the throttling element is smaller than the cross-sectional area of ​​the exhaust pipe. The differential pressure sensor is used to monitor the pressure difference between the pipe segment where the throttling element is located and other pipe segments in the exhaust pipe to determine the flow rate. An EGR valve is located on the exhaust pipe of the engine and on one side of the differential pressure flow meter. The device includes: a first determining unit, used to determine a correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve, wherein the correlation formula is that the differential pressure value is equal to the product of the opening value and a proportional coefficient plus an offset value; and a first acquiring unit, used to acquire multiple opening values ​​and The pressure difference value and the opening value correspond one-to-one with the pressure difference value; the processing unit is used to process the correlation formula using the least squares method to obtain a variance function, which is a function to calculate the variance of the two sides of the mathematical expression of the correlation formula. The optimal offset value is calculated by substituting multiple opening values ​​and the corresponding pressure difference values ​​into the variance function. The optimal offset value is the offset value corresponding to the minimum function value of the variance function; the calculation unit is used to obtain the pressure difference value of the pressure difference sensor when the optimal offset value is less than or equal to the offset threshold, obtain the current pressure difference value, and calculate the difference between the current pressure difference value and the optimal offset value to obtain a corrected pressure difference value; the second determining unit is used to determine the flow rate of the exhaust pipeline based on the corrected pressure difference value.

[0012] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform any of the methods described.

[0013] According to another aspect of this application, a differential pressure flow meter management system is provided, comprising: a differential pressure flow meter, one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include methods for performing any one of the methods described.

[0014] Applying the technical solution of this application, in the method for correcting the flow rate of a differential pressure flow meter, firstly, the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve is determined. The correlation is that the differential pressure value equals the product of the opening value and the proportional coefficient plus an offset value. Then, multiple opening values ​​and corresponding differential pressure values ​​are obtained, with each opening value corresponding to a different differential pressure value. Next, the correlation is processed using the least squares method to obtain a variance function, which is a function that calculates the variance of both sides of the correlation. The multiple opening values ​​and corresponding differential pressure values ​​are substituted into the variance function to calculate the optimal offset value, which is the offset value corresponding to the minimum function value of the variance function. Then, if the optimal offset value is less than or equal to an offset threshold, the differential pressure value of the differential pressure sensor is obtained to obtain the current differential pressure value. The difference between the current differential pressure value and the optimal offset value is calculated to obtain the corrected differential pressure value. Finally, the flow rate of the exhaust pipe is determined based on the corrected differential pressure value. This application controls the EGR valve opening by establishing a linear relationship between the EGR valve opening value and the differential pressure sensor. Multiple sampling points within the opening range are collected, and the differential pressure from the sensor and the EGR valve opening value at each sampling point are recorded. These values ​​are then calculated using the least squares formula to determine the optimal offset and optimal proportional coefficient. If the optimal offset is less than or equal to a threshold, the difference between the current differential pressure value and the optimal offset is calculated to obtain a corrected differential pressure value. The flow rate in the exhaust pipe is then determined based on this corrected differential pressure value. This application solves the problem of inaccurate flow measurement caused by zero-point drift in existing differential pressure sensors. Attached Figure Description

[0015] Figure 1 A hardware block diagram of a mobile terminal for performing a method for correcting the flow rate of a differential pressure flow meter, according to an embodiment of this application, is shown.

[0016] Figure 2A schematic flowchart of a method for correcting the flow rate of a differential pressure flow meter according to an embodiment of this application is shown.

[0017] Figure 3 A flowchart illustrating a method for determining the offset value of zero drift of a differential pressure flow meter according to an embodiment of this application is shown.

[0018] Figure 4 A schematic flowchart of a secondary diagnostic method for a differential pressure flowmeter according to an embodiment of this application is shown.

[0019] Figure 5 A schematic flowchart of a method for correcting the flow rate of a differential pressure flow meter according to an embodiment of this application is shown.

[0020] Figure 6 A structural block diagram of a flow correction device for a differential pressure flow meter provided according to an embodiment of this application is shown.

[0021] The above figures include the following reference numerals:

[0022] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0027] The EGR valve, also known as the exhaust gas recirculation valve, is an electromechanical product installed on the engine to control the amount of exhaust gas recirculated back to the intake system.

[0028] As described in the background section, the existing zero-point drift diagnostic strategy generally involves learning the deviation voltage as the zero point when the engine is not running and the EGR valve is closed (zero flow). To address the problem of inaccurate flow measurement caused by zero-point drift in differential pressure sensors in the prior art, embodiments of this application provide a method for correcting the flow of a differential pressure flow meter, a correction device, a computer-readable storage medium, and a differential pressure flow meter management system.

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal for a method of correcting the flow rate of a differential pressure flow meter according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0031] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the device information display method in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory and non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the aforementioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the aforementioned networks may include wireless networks provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0032] This embodiment provides a method for correcting the flow rate of a differential pressure flow meter that operates on a mobile terminal, computer terminal, or similar computing device. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] Figure 2 This is a flowchart of a flow correction method for a differential pressure flow meter according to an embodiment of this application. Figure 2 As shown, the method includes the following steps:

[0034] Step S201: Determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value.

[0035] Specifically, first determine the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The specific formula for the correlation is: U = bK + a, where U is the differential pressure value of the differential pressure sensor; b and a are unknown parameters, b is the proportional coefficient, a is the offset value, and K is the opening value of the EGR valve.

[0036] Step S202: Obtain multiple opening values ​​and corresponding differential pressure values, with each opening value corresponding to a different differential pressure value.

[0037] Specifically, the opening degree of the EGR valve is adjusted. Each adjustment of the EGR valve opening degree will result in a corresponding opening degree value. Similarly, each opening degree value will correspond to a differential pressure value, thereby obtaining multiple opening degree values ​​and corresponding differential pressure values.

[0038] Step S203: The least squares method is used to process the above correlation formula to obtain the variance function. The variance function is a function that calculates the variance of the two sides of the above correlation formula. The multiple opening values ​​and the corresponding pressure difference values ​​are substituted into the variance function to calculate the optimal offset value. The optimal offset value is the offset value corresponding to the minimum function value of the variance function.

[0039] Specifically, the least squares method is used to process the above correlation expression to obtain the variance function, and the specific formula of the variance function is as follows: Among them, i=1, 2,...,m; U i K represents the differential pressure value of the differential pressure sensor at point i; i For the EGR valve opening value at point i, substitute multiple opening values ​​and the corresponding differential pressure values ​​into the variance function to calculate the value. When the value of 'a' is minimized, the resulting 'a' is the optimal offset value.

[0040] Step S204: When the above-mentioned optimal offset value is less than or equal to the offset threshold, obtain the differential pressure value of the above-mentioned differential pressure sensor, obtain the current differential pressure value, and calculate the difference between the above-mentioned current differential pressure value and the above-mentioned optimal offset value to obtain the corrected differential pressure value.

[0041] Specifically, if the above-mentioned optimal offset value is less than or equal to the offset threshold, it means that the zero-point offset is within the allowable range and only zero-point correction is needed. If there is zero-point drift, when the opening value is 0, the deviation can be approximately equal to the above-mentioned optimal offset value.

[0042] Step S205: Determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value.

[0043] Specifically, the differential pressure value is corrected to the above-mentioned corrected differential pressure value, and the differential pressure flow meter can determine the flow rate of the above-mentioned exhaust pipeline by measuring according to the above-mentioned corrected differential pressure value.

[0044] Through the above embodiments, firstly, the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve is determined. The correlation is that the differential pressure value equals the product of the opening value and the proportional coefficient plus an offset value. Then, multiple opening values ​​and corresponding differential pressure values ​​are obtained, with each opening value corresponding to a different differential pressure value. Next, the correlation is processed using the least squares method to obtain a variance function, which is a function that calculates the variance of both sides of the correlation. Substituting the multiple opening values ​​and corresponding differential pressure values ​​into the variance function, the optimal offset value is calculated. The optimal offset value is the offset value corresponding to the minimum function value of the variance function. Then, if the optimal offset value is less than or equal to an offset threshold, the differential pressure value of the differential pressure sensor is obtained to obtain the current differential pressure value. The difference between the current differential pressure value and the optimal offset value is calculated to obtain a corrected differential pressure value. Finally, the flow rate of the exhaust pipe is determined based on the corrected differential pressure value. This application controls the EGR valve opening by establishing a linear relationship between the EGR valve opening value and the differential pressure sensor. Multiple sampling points within the opening range are collected, and the differential pressure from the sensor and the EGR valve opening value at each sampling point are recorded. These values ​​are then calculated using the least squares formula to determine the optimal offset and optimal proportional coefficient. If the optimal offset is less than or equal to a threshold, the difference between the current differential pressure value and the optimal offset is calculated to obtain a corrected differential pressure value. The flow rate in the exhaust pipe is then determined based on this corrected differential pressure value. This application solves the problem of inaccurate flow measurement caused by zero-point drift in existing differential pressure sensors.

[0045] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the flow correction method of the differential pressure flowmeter of this application will be described in detail below with reference to specific embodiments.

[0046] To accurately determine zero-point drift, in one optional implementation, before step S202, the method further includes:

[0047] Step S301: Obtain engine operating condition data, including fuel injection quantity, engine speed and engine temperature.

[0048] Specifically, in order to accurately determine zero-point drift, a stable steady-state operating condition of the engine is selected, which includes fuel injection quantity, engine speed and engine temperature.

[0049] Step S302: Determine whether each of the above operating condition data meets the corresponding preset requirements. The preset requirements include that the fuel injection quantity is greater than or equal to the fuel injection quantity threshold, the engine speed is greater than or equal to the engine speed threshold, and the engine temperature is within a predetermined temperature range. The fuel injection quantity threshold and the engine speed threshold are the minimum fuel injection quantity and the minimum engine speed for stable engine operation, respectively. The predetermined temperature range is the temperature range for stable engine operation. Different specific values ​​can be set according to the steady-state operating condition data of different engines. Those skilled in the art can select appropriate values ​​according to the actual situation.

[0050] Specifically, zero-point drift diagnosis will be more accurate when the operating condition data meets the corresponding preset requirements. Therefore, it is necessary to first determine whether the above-mentioned operating condition data meets the corresponding preset requirements.

[0051] Step S303: If any of the above-mentioned working condition data fails to meet the corresponding preset requirements, continue to acquire the above-mentioned working condition data until all of the above-mentioned working condition data meet the corresponding preset requirements.

[0052] Specifically, if any of the above-mentioned operating condition data fails to meet the corresponding preset requirements, it indicates that the engine's operating condition is unstable and there is a high probability of zero-point drift. In this case, the diagnostic correction results will also be inaccurate. Therefore, the above-mentioned operating condition data will continue to be acquired until all of the above-mentioned operating condition data meet the corresponding preset requirements.

[0053] To improve the accuracy of zero-point drift diagnosis, in one optional implementation, step S202 includes:

[0054] Step S2021: Control the EGR valve to adjust the opening value within the opening range and obtain the corresponding differential pressure value, thereby obtaining multiple opening values ​​and corresponding differential pressure values. The opening range is the range of the opening values ​​corresponding to the EGR valve when the engine temperature is within a predetermined temperature range.

[0055] Specifically, in order to ensure accurate measurement so that the engine temperature remains basically unchanged before and after adjusting the EGR valve opening, i.e., the temperature is within the predetermined temperature range, controlling the EGR valve to adjust the opening value within the opening range can ensure that the engine can obtain the best performance and exhaust emission control under different operating conditions. By adjusting the opening value of the EGR valve, the exhaust gas recirculation flow rate can be controlled. By detecting the differential pressure value corresponding to different opening values, the diagnosis of zero-point drift of the differential pressure flow meter can be optimized.

[0056] To optimize parameter configuration, in one optional implementation, step S203 includes:

[0057] Step S2031: Use the partial derivative method to find the partial derivative of the proportional coefficient of the above variance function to obtain the first partial derivative function.

[0058] Specifically, variance function Taking the partial derivative with respect to the proportionality constant b, we get This is the first partial derivative function mentioned above.

[0059] Step S2032: Using the above-described method of finding partial derivatives, the partial derivative of the above-described variance function is calculated to obtain the second partial derivative function.

[0060] Specifically, variance function Taking the partial derivative with respect to the offset value a, we get This is the second partial derivative function mentioned above.

[0061] Step S2033: Calculate the offset value corresponding to the case where both the first partial derivative function and the second partial derivative function are equal to 0, and obtain the optimal offset value.

[0062] Specifically, let The optimal offset value is calculated.

[0063] To improve the reliability of the correction, in one alternative implementation, such as Figure 3 As shown, step S2033 includes:

[0064] Step S20331: When the first partial derivative function and the second partial derivative function are both equal to 0, the elimination method is used to calculate and process them simultaneously to obtain the offset value relationship and the proportional coefficient relationship. The offset value relationship does not contain the proportional coefficient, and the proportional coefficient relationship does not contain the offset value.

[0065] Specifically, let The offset value relationship is calculated as follows:

[0066] proportionality coefficient formula:

[0067] The proportionality coefficient relationship is simplified to obtain the simplified proportionality coefficient relationship: Where K is the average of all opening values, and U is the average of all differential pressure values.

[0068] The formula for the optimal offset value 'a' is simplified to obtain the simplified offset value relationship: a = U - bK, where K is the average value of all opening values ​​and U is the average value of all pressure difference values.

[0069] Step S20332: Calculate the average value of all the above opening values ​​and the average value of all the above pressure difference values ​​to obtain the average opening value and the average pressure difference value.

[0070] Specifically, the average of all opening values ​​is calculated to obtain the average opening value K, and the average of all pressure difference values ​​is calculated to obtain the average pressure difference value U.

[0071] Step S20333: Substitute multiple opening values, multiple differential pressure values, average opening value, and average differential pressure value into the above proportional coefficient relationship to calculate the optimal proportional coefficient.

[0072] Specifically, multiple opening values ​​K mentioned above will be used. i Multiple differential pressure values ​​U mentioned above i Substituting the average opening value K and the average pressure difference U into the proportionality coefficient formula: The optimal proportional coefficient b is obtained through calculation.

[0073] Step S20334: Substitute the above-mentioned optimal proportional coefficient, the above-mentioned average opening value, and the above-mentioned average pressure difference value into the above-mentioned offset value relationship to calculate the above-mentioned optimal offset value.

[0074] Specifically, the optimal proportional coefficient b, the average opening value K, and the average pressure difference U are substituted into the offset value relationship: a = U - bK to calculate the optimal offset value a.

[0075] To promptly alert and repair zero-point drift faults and reduce risk, in one optional implementation, after step S203, the method further includes:

[0076] Step S401: If the optimal offset value is greater than the offset threshold, the control issues a first fault alarm. The first fault alarm is used to indicate that the differential pressure flow meter has a zero-point drift fault.

[0077] Specifically, if the optimal offset value is greater than the offset threshold, it indicates that the zero-point offset is too large and exceeds the allowable range, and a fault alarm is issued to indicate that the differential pressure flow meter has a zero-point drift fault. Another method for determining zero-point offset faults involves storing the calculated optimal offset value in the engine electronic control unit (ECU) and comparing it with the previous offset value calculation result. If the change between the current calculated optimal offset value and the previous offset value calculation result is greater than the change threshold, a fault alarm is also issued.

[0078] To avoid multiple faults affecting the flow measurement of the differential pressure flow meter, in one optional implementation, after step S205, as follows: Figure 4 As shown, the method also includes:

[0079] Step S601: Based on the above-mentioned corrected pressure difference value, the theoretical value of the exhaust gas flow rate corresponding to the above-mentioned corrected pressure difference value is obtained by querying the exhaust gas flow rate comparison table. The above-mentioned exhaust gas flow rate comparison table is a comparison table of the above-mentioned pressure difference value, the above-mentioned opening value and the above-mentioned theoretical value of exhaust gas flow rate.

[0080] Specifically, after correcting the differential pressure value to the corrected differential pressure value, the theoretical value of the exhaust gas flow rate corresponding to the corrected differential pressure value is obtained by referring to the exhaust gas flow rate comparison table.

[0081] In step S602, if the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is greater than the error threshold, a second fault alarm is issued. The second fault alarm is used to remind the differential pressure flow meter of any fault other than zero-point drift fault.

[0082] Specifically, if the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is greater than the error threshold, it indicates that even after the pressure difference correction has solved the zero-point drift problem, there is still a flow rate problem affecting the exhaust pipe, that is, there is a fault problem other than the zero-point drift fault, and a second fault alarm is issued.

[0083] Step S603: If the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is less than or equal to the error threshold, it is determined that the differential pressure flow meter is fault-free.

[0084] Specifically, if the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is less than or equal to the error threshold, it indicates that the differential pressure value correction has solved the zero-point drift problem and there are no other problems affecting the flow rate of the exhaust pipe. Therefore, it can be determined that the differential pressure flow meter is fault-free.

[0085] This embodiment relates to a specific method for correcting the flow rate of a differential pressure flow meter, such as... Figure 5 As shown, it includes the following steps:

[0086] Step S1: Check whether the engine operating data has reached steady-state operating conditions. The operating data includes: fuel level, engine speed, and engine temperature.

[0087] Step S2: After reaching steady-state operation, select and control the EGR opening, collect data at multiple sampling points within the opening range, record the corresponding differential pressure sensor differential pressure and EGR opening at each sampling point, and substitute them into the least squares formula. Perform calculations to determine the corresponding parameters a and b;

[0088] Step S3: Compare the calculated 'a' with the calculated 'a' to see if it is within the allowable range. If it is outside the range, report a fault. Alternatively, store the calculated parameter 'a' in the ECU and compare it with the previously calculated parameter 'a'. If the change is too large, report a fault.

[0089] Step S4: If the fault reporting threshold is not exceeded, the differential pressure is corrected using parameters. Based on the calculated quadratic equation U = bK + a, it can be concluded that when the opening is 0, if zero-point drift exists, the deviation can be approximately equal to a. Therefore, the differential pressure U of the differential pressure sensor can be approximately considered to be... 修 =U-a.

[0090] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0091] This application also provides a flow correction device for a differential pressure flow meter. It should be noted that the flow correction device for a differential pressure flow meter in this application can be used to execute the flow correction method for a differential pressure flow meter provided in this application. This device is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0092] The following describes the flow correction device for the differential pressure flow meter provided in the embodiments of this application.

[0093] Figure 6 This is a structural block diagram of a flow correction device for a differential pressure flowmeter according to an embodiment of this application. Figure 6 As shown, the device includes:

[0094] The first determining unit 10 is used to determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value.

[0095] Specifically, first determine the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The specific formula for the correlation is: U = bK + a, where U is the differential pressure value of the differential pressure sensor; b and a are unknown parameters, b is the proportional coefficient, a is the offset value, and K is the opening value of the EGR valve.

[0096] The first acquisition unit 20 is used to acquire multiple opening values ​​and corresponding differential pressure values, wherein the opening values ​​and differential pressure values ​​correspond one-to-one.

[0097] Specifically, the opening degree of the EGR valve is adjusted. Each adjustment of the EGR valve opening degree will result in a corresponding opening degree value. Similarly, each opening degree value will correspond to a differential pressure value, thereby obtaining multiple opening degree values ​​and corresponding differential pressure values.

[0098] The processing unit 30 is used to process the above correlation formula using the least squares method to obtain a variance function. The variance function is a function that calculates the variance of the two sides of the above correlation formula. The optimal offset value is obtained by substituting multiple above opening values ​​and the corresponding above pressure difference values ​​into the above variance function. The optimal offset value is the offset value corresponding to the minimum function value of the above variance function.

[0099] Specifically, the least squares method is used to process the above correlation expression to obtain the variance function, and the specific formula of the variance function is as follows: Among them, i=1, 2,...,m; U i K represents the differential pressure value of the differential pressure sensor at point i; i For the EGR valve opening value at point i, substitute multiple opening values ​​and the corresponding differential pressure values ​​into the variance function to calculate the value. When the value of 'a' is minimized, the resulting 'a' is the optimal offset value.

[0100] The calculation unit 40 is used to obtain the differential pressure value of the differential pressure sensor when the above-mentioned optimal offset value is less than or equal to the offset threshold, obtain the current differential pressure value, and calculate the difference between the above-mentioned current differential pressure value and the above-mentioned optimal offset value to obtain the corrected differential pressure value.

[0101] Specifically, if the above-mentioned optimal offset value is less than or equal to the offset threshold, it means that the zero-point offset is within the allowable range and only zero-point correction is needed. If there is zero-point drift, when the opening value is 0, the deviation can be approximately equal to the above-mentioned optimal offset value.

[0102] The second determining unit 50 is used to determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value.

[0103] Specifically, the differential pressure value is corrected to the above-mentioned corrected differential pressure value, and the differential pressure flow meter can determine the flow rate of the above-mentioned exhaust pipeline by measuring according to the above-mentioned corrected differential pressure value.

[0104] In this embodiment, the first determining unit is used to determine the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve, wherein the differential pressure value is equal to the product of the opening value and the proportional coefficient plus an offset value; the first acquiring unit is used to acquire multiple opening values ​​and corresponding differential pressure values, wherein the opening value and the differential pressure value correspond one-to-one; the processing unit is used to process the correlation using the least squares method to obtain a variance function, wherein the variance function is a function for calculating the variance of both sides of the correlation, and the multiple opening values ​​and the corresponding differential pressure values ​​are substituted into the variance function to calculate the optimal offset value, wherein the optimal offset value is the offset value corresponding to the minimum function value of the variance function; the calculation unit is used to acquire the differential pressure value of the differential pressure sensor when the optimal offset value is less than or equal to an offset threshold, obtain the current differential pressure value, and calculate the difference between the current differential pressure value and the optimal offset value to obtain a corrected differential pressure value; the second determining unit is used to determine the flow rate of the exhaust pipe based on the corrected differential pressure value. This application controls the EGR valve opening by establishing a linear relationship between the EGR valve opening value and the differential pressure sensor. Multiple sampling points within the opening range are collected, and the differential pressure from the sensor and the EGR valve opening value at each sampling point are recorded. These values ​​are then calculated using the least squares formula to determine the optimal offset and optimal proportional coefficient. If the optimal offset is less than or equal to a threshold, the difference between the current differential pressure value and the optimal offset is calculated to obtain a corrected differential pressure value. The flow rate in the exhaust pipe is then determined based on this corrected differential pressure value. This application solves the problem of inaccurate flow measurement caused by zero-point drift in existing differential pressure sensors.

[0105] In order to accurately determine zero-point drift, in one optional embodiment, the device further includes:

[0106] The second acquisition unit is used to acquire engine operating condition data before acquiring multiple opening values ​​and corresponding differential pressure values, wherein the opening values ​​and differential pressure values ​​correspond one-to-one. The operating condition data includes fuel injection quantity, engine speed and engine temperature.

[0107] Specifically, in order to accurately determine zero-point drift, a stable steady-state operating condition of the engine is selected, which includes fuel injection quantity, engine speed and engine temperature.

[0108] The judgment unit is used to determine whether the above-mentioned operating condition data meet the corresponding preset requirements. The preset requirements include that the fuel injection quantity is greater than or equal to the fuel injection quantity threshold, the engine speed is greater than or equal to the engine speed threshold, and the engine temperature is within a predetermined temperature range. The fuel injection quantity threshold and the engine speed threshold are the minimum fuel injection quantity and the minimum engine speed for stable engine operation, respectively. The predetermined temperature range is the temperature range for stable engine operation. Different specific values ​​can be set according to the steady-state operating condition data of different engines. Those skilled in the art can select appropriate values ​​according to the actual situation.

[0109] Specifically, zero-point drift diagnosis will be more accurate when the operating condition data meets the corresponding preset requirements. Therefore, it is necessary to first determine whether the above-mentioned operating condition data meets the corresponding preset requirements.

[0110] The third acquisition unit is used to continue acquiring the above-mentioned working condition data until all the above-mentioned working condition data meet the corresponding preset requirements if any of the above-mentioned working condition data fails to meet the corresponding preset requirements.

[0111] Specifically, if any of the above-mentioned operating condition data fails to meet the corresponding preset requirements, it indicates that the engine's operating condition is unstable and there is a high probability of zero-point drift. In this case, the diagnostic correction results will also be inaccurate. Therefore, the above-mentioned operating condition data will continue to be acquired until all of the above-mentioned operating condition data meet the corresponding preset requirements.

[0112] To improve the accuracy of zero-point drift diagnosis, in one optional embodiment, the first acquisition unit includes:

[0113] The acquisition module controls the EGR valve to adjust the opening value within the opening range and acquires the corresponding differential pressure value, thereby obtaining multiple opening values ​​and corresponding differential pressure values. The opening range is the range of the opening values ​​corresponding to the EGR valve when the engine temperature is within a predetermined temperature range.

[0114] Specifically, in order to ensure accurate measurement so that the engine temperature remains basically unchanged before and after adjusting the EGR valve opening, i.e., the temperature is within the predetermined temperature range, controlling the EGR valve to adjust the opening value within the opening range can ensure that the engine can obtain the best performance and exhaust emission control under different operating conditions. By adjusting the opening value of the EGR valve, the exhaust gas recirculation flow rate can be controlled. By detecting the differential pressure value corresponding to different opening values, the diagnosis of zero-point drift of the differential pressure flow meter can be optimized.

[0115] To optimize parameter configuration, in one optional implementation, the processing unit includes:

[0116] The first processing module uses the partial derivative method to find the partial derivative of the proportional coefficient in the expression of the variance function to obtain the first partial derivative function.

[0117] Specifically, variance function Taking the partial derivative with respect to the proportionality constant b, we get This is the first partial derivative function mentioned above.

[0118] The second processing module uses the aforementioned partial derivative method to calculate the partial derivative of the offset value in the expression of the variance function, thereby obtaining the second partial derivative function.

[0119] Specifically, variance function Taking the partial derivative with respect to the offset value a, we get This is the second partial derivative function mentioned above.

[0120] The calculation module calculates the offset value corresponding to the case where both the first partial derivative function and the second partial derivative function are equal to 0, and obtains the optimal offset value.

[0121] Specifically, let The optimal offset value is calculated.

[0122] To improve the reliability of the correction, in one optional implementation, the above-mentioned calculation module includes:

[0123] The processing submodule performs simultaneous elimination calculations when both the first partial derivative function and the second partial derivative function are equal to 0, to obtain the offset value relationship and the proportional coefficient relationship. The offset value relationship does not contain the proportional coefficient, and the proportional coefficient relationship does not contain the offset value.

[0124] Specifically, let The offset value relationship is calculated as follows:

[0125] proportionality coefficient formula:

[0126] The proportionality coefficient relationship is simplified to obtain the simplified proportionality coefficient relationship: Where K is the average of all opening values, and U is the average of all differential pressure values.

[0127] The formula for the optimal offset value 'a' is simplified to obtain the simplified offset value relationship: a = U - bK, where K is the average value of all opening values ​​and U is the average value of all pressure difference values.

[0128] The first calculation submodule calculates the average value of all the above opening values ​​and the average value of all the above pressure difference values ​​respectively, to obtain the average opening value and the average pressure difference value.

[0129] Specifically, the average of all opening values ​​is calculated to obtain the average opening value K, and the average of all pressure difference values ​​is calculated to obtain the average pressure difference value U.

[0130] The second calculation submodule substitutes multiple opening values, multiple differential pressure values, the average opening value, and the average differential pressure value into the above proportional coefficient formula to calculate the optimal proportional coefficient.

[0131] Specifically, multiple opening values ​​K mentioned above will be used. i Multiple differential pressure values ​​U mentioned above i Substituting the average opening value K and the average pressure difference U into the proportionality coefficient formula: The optimal proportional coefficient b is obtained through calculation.

[0132] The third calculation submodule substitutes the above-mentioned optimal proportional coefficient, the above-mentioned average opening value, and the above-mentioned average pressure difference value into the above-mentioned offset value relationship to calculate the above-mentioned optimal offset value.

[0133] Specifically, the optimal proportional coefficient b, the average opening value K, and the average pressure difference U are substituted into the offset value relationship: a = U - bK to calculate the optimal offset value a.

[0134] To promptly alert and repair zero-point drift faults and reduce risks, in one optional embodiment, the device further includes:

[0135] The first alarm unit is used to calculate the optimal offset value by substituting multiple opening values ​​and the corresponding differential pressure values ​​into the variance function. If the optimal offset value is greater than the offset threshold, the unit controls the issuance of a first fault alarm. The first fault alarm is used to indicate that the differential pressure flow meter has a zero-point drift fault.

[0136] Specifically, if the optimal offset value is greater than the offset threshold, it indicates that the zero-point offset is too large and exceeds the allowable range, and a fault alarm is issued to indicate that the differential pressure flow meter has a zero-point drift fault. Another method for determining zero-point offset faults involves storing the calculated optimal offset value in the engine electronic control unit (ECU) and comparing it with the previous offset value calculation result. If the change between the current calculated optimal offset value and the previous offset value calculation result is greater than the change threshold, a fault alarm is also issued.

[0137] To prevent multiple malfunctions from affecting the flow measurement of the differential pressure flow meter, in one optional embodiment, the device further includes:

[0138] The query unit is used to determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value, and then query the exhaust gas flow rate lookup table based on the above-mentioned corrected pressure difference value to obtain the theoretical value of the exhaust gas flow rate corresponding to the above-mentioned corrected pressure difference value. The above-mentioned exhaust gas flow rate lookup table is a lookup table of the above-mentioned pressure difference value, the above-mentioned opening value and the above-mentioned theoretical value of the exhaust gas flow rate.

[0139] Specifically, after correcting the differential pressure value to the corrected differential pressure value, the theoretical value of the exhaust gas flow rate corresponding to the corrected differential pressure value is obtained by referring to the exhaust gas flow rate comparison table.

[0140] The second alarm unit issues a second fault alarm when the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is greater than the error threshold. The second fault alarm is used to remind the differential pressure flow meter of any fault other than zero-point drift.

[0141] Specifically, if the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is greater than the error threshold, it indicates that even after the pressure difference correction has solved the zero-point drift problem, there is still a flow rate problem affecting the exhaust pipe, that is, there is a fault problem other than the zero-point drift fault, and a second fault alarm is issued.

[0142] The third determining unit determines that the differential pressure flow meter is fault-free if the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is less than or equal to the error threshold.

[0143] Specifically, if the difference between the flow rate of the exhaust pipe and the theoretical value of the exhaust gas flow rate is less than or equal to the error threshold, it indicates that the differential pressure value correction has solved the zero-point drift problem and there are no other problems affecting the flow rate of the exhaust pipe. Therefore, it can be determined that the differential pressure flow meter is fault-free.

[0144] The flow correction device of the aforementioned differential pressure flowmeter includes a processor and a memory. The first determining unit, the acquiring unit, and the processing unit are all stored as program units in the memory, and the processor executes the program units stored in the memory to achieve the corresponding functions. All of the above modules are located in the same processor; alternatively, the modules may be located in different processors in any combination.

[0145] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and adjusting the kernel parameters solves the problem of inaccurate flow measurement caused by zero-point drift in existing differential pressure sensors.

[0146] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0147] This invention provides a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the flow correction method of the differential pressure flow meter.

[0148] Specifically, the methods for correcting the flow rate of a differential pressure flow meter include:

[0149] Step S201: Determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value.

[0150] Step S202: Obtain multiple opening values ​​and corresponding differential pressure values, with each opening value corresponding to a differential pressure value.

[0151] Step S203: The least squares method is used to process the above correlation formula to obtain the variance function. The variance function is a function to calculate the variance of the two sides of the above correlation formula. The multiple opening values ​​and the corresponding pressure difference values ​​are substituted into the variance function to calculate the optimal offset value. The optimal offset value is the offset value corresponding to the minimum function value of the variance function.

[0152] Step S204: When the above-mentioned optimal offset value is less than or equal to the offset threshold, obtain the differential pressure value of the above-mentioned differential pressure sensor, obtain the current differential pressure value, and calculate the difference between the above-mentioned current differential pressure value and the above-mentioned optimal offset value to obtain the corrected differential pressure value.

[0153] Step S205: Determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value.

[0154] This invention provides a processor for running a program, wherein the program executes the flow correction method of the differential pressure flow meter.

[0155] Specifically, the methods for correcting the flow rate of a differential pressure flow meter include:

[0156] Step S201: Determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value.

[0157] Step S202: Obtain multiple opening values ​​and corresponding differential pressure values, with each opening value corresponding to a differential pressure value.

[0158] Step S203: The least squares method is used to process the above correlation formula to obtain the variance function. The variance function is a function to calculate the variance of the two sides of the above correlation formula. The multiple opening values ​​and the corresponding pressure difference values ​​are substituted into the variance function to calculate the optimal offset value. The optimal offset value is the offset value corresponding to the minimum function value of the variance function.

[0159] Step S204: When the above-mentioned optimal offset value is less than or equal to the offset threshold, obtain the differential pressure value of the above-mentioned differential pressure sensor, obtain the current differential pressure value, and calculate the difference between the above-mentioned current differential pressure value and the above-mentioned optimal offset value to obtain the corrected differential pressure value.

[0160] Step S205: Determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value.

[0161] This invention provides a differential pressure flow meter management system, including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0162] Step S201: Determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value.

[0163] Step S202: Obtain multiple opening values ​​and corresponding differential pressure values, with each opening value corresponding to a differential pressure value.

[0164] Step S203: The least squares method is used to process the above correlation formula to obtain the variance function. The variance function is a function to calculate the variance of the two sides of the above correlation formula. The multiple opening values ​​and the corresponding pressure difference values ​​are substituted into the variance function to calculate the optimal offset value. The optimal offset value is the offset value corresponding to the minimum function value of the variance function.

[0165] Step S204: When the above-mentioned optimal offset value is less than or equal to the offset threshold, obtain the differential pressure value of the above-mentioned differential pressure sensor, obtain the current differential pressure value, and calculate the difference between the above-mentioned current differential pressure value and the above-mentioned optimal offset value to obtain the corrected differential pressure value.

[0166] Step S205: Determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value.

[0167] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0168] Step S201: Determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value.

[0169] Step S202: Obtain multiple opening values ​​and corresponding differential pressure values, with each opening value corresponding to a differential pressure value.

[0170] Step S203: The least squares method is used to process the above correlation formula to obtain the variance function. The variance function is a function to calculate the variance of the two sides of the above correlation formula. The multiple opening values ​​and the corresponding pressure difference values ​​are substituted into the variance function to calculate the optimal offset value. The optimal offset value is the offset value corresponding to the minimum function value of the variance function.

[0171] Step S204: When the above-mentioned optimal offset value is less than or equal to the offset threshold, obtain the differential pressure value of the above-mentioned differential pressure sensor, obtain the current differential pressure value, and calculate the difference between the above-mentioned current differential pressure value and the above-mentioned optimal offset value to obtain the corrected differential pressure value.

[0172] Step S205: Determine the flow rate of the exhaust pipeline based on the above-mentioned corrected pressure difference value.

[0173] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0174] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0175] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0176] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0177] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0178] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0179] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0180] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0181] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0182] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0183] 1) The method for correcting the flow rate of the differential pressure flow meter of this application firstly determines the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve. The correlation is that the differential pressure value equals the product of the opening value and the proportional coefficient plus an offset value. Then, multiple opening values ​​and corresponding differential pressure values ​​are obtained, with each opening value corresponding to a different differential pressure value. Next, the correlation is processed using the least squares method to obtain a variance function, which is a function that calculates the variance of both sides of the correlation. The multiple opening values ​​and corresponding differential pressure values ​​are substituted into the variance function to calculate the optimal offset value, which is the offset value corresponding to the minimum function value of the variance function. Then, if the optimal offset value is less than or equal to an offset threshold, the differential pressure value of the differential pressure sensor is obtained to obtain the current differential pressure value. The difference between the current differential pressure value and the optimal offset value is calculated to obtain a corrected differential pressure value. Finally, the flow rate of the exhaust pipe is determined based on the corrected differential pressure value. This application controls the EGR valve opening by establishing a linear relationship between the EGR valve opening value and the differential pressure sensor. Multiple sampling points within the opening range are collected, and the differential pressure from the sensor and the EGR valve opening value at each sampling point are recorded. These values ​​are then calculated using the least squares formula to determine the optimal offset and optimal proportional coefficient. If the optimal offset is less than or equal to a threshold, the difference between the current differential pressure value and the optimal offset is calculated to obtain a corrected differential pressure value. The flow rate in the exhaust pipe is then determined based on this corrected differential pressure value. This application solves the problem of inaccurate flow measurement caused by zero-point drift in existing differential pressure sensors.

[0184] 2) The flow correction device for the differential pressure flowmeter of this application includes a first determining unit for determining the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve, wherein the correlation is that the differential pressure value equals the product of the opening value and the proportional coefficient plus an offset value; a first acquiring unit for acquiring multiple opening values ​​and corresponding differential pressure values, wherein the opening value and the differential pressure value correspond one-to-one; and a processing unit for processing the correlation using the least squares method to obtain a variance function, wherein the variance function is used to calculate the correlation. The system uses a function of the variance of both sides of the mathematical formula to calculate the optimal offset value by substituting multiple opening values ​​and corresponding differential pressure values ​​into the variance function. The optimal offset value is the offset value corresponding to the minimum function value of the variance function. The calculation unit is used to obtain the differential pressure value of the differential pressure sensor when the optimal offset value is less than or equal to the offset threshold, obtain the current differential pressure value, and calculate the difference between the current differential pressure value and the optimal offset value to obtain a corrected differential pressure value. The second determination unit is used to determine the flow rate of the exhaust pipe based on the corrected differential pressure value. This application sets a linear relationship between the EGR valve opening value and the differential pressure sensor, controls the EGR valve opening value, collects data from multiple sampling points within the opening range, records the differential pressure sensor pressure and the EGR valve opening value at each sampling point, substitutes them into the least squares formula for calculation, calculates the corresponding optimal offset value and optimal proportional coefficient, calculates the difference between the current differential pressure value and the optimal offset value to obtain a corrected differential pressure value when the optimal offset value is less than or equal to the threshold, and determines the flow rate of the exhaust pipe based on the corrected differential pressure value. This application solves the problem of inaccurate flow measurement caused by zero-point drift in differential pressure sensors in the prior art.

[0185] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for correcting the flow rate of a differential pressure flow meter, characterized in that, The differential pressure flow meter includes a differential pressure sensor and a throttling element. The throttling element is located on the exhaust pipe of the engine, and its cross-sectional area is smaller than that of the exhaust pipe. The differential pressure sensor is used to monitor the pressure difference between the section of the exhaust pipe where the throttling element is located and other sections to determine the flow rate. An EGR valve is located on the exhaust pipe of the engine and on one side of the differential pressure flow meter. The method includes: Determine the correlation between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve, wherein the correlation is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value; Multiple opening values ​​and corresponding differential pressure values ​​are obtained, with each opening value and differential pressure value corresponding one-to-one; The least squares method is used to process the correlation formula to obtain a variance function. The variance function is a function that calculates the variance of the two sides of the mathematical expression of the correlation formula. The optimal offset value is calculated by substituting multiple opening values ​​and the corresponding pressure difference values ​​into the variance function. The optimal offset value is the offset value corresponding to the minimum function value of the variance function. When the optimal offset value is less than or equal to the offset threshold, the differential pressure value of the differential pressure sensor is obtained, the current differential pressure value is obtained, and the difference between the current differential pressure value and the optimal offset value is calculated to obtain the corrected differential pressure value. The flow rate of the exhaust pipe is determined based on the corrected differential pressure value; The optimal offset value is calculated by substituting multiple opening values ​​and corresponding pressure difference values ​​into the variance function, including: taking the partial derivative of the proportional coefficient with respect to the expression of the variance function using the partial derivative method to obtain a first partial derivative function; taking the partial derivative of the offset value with respect to the expression of the variance function using the partial derivative method to obtain a second partial derivative function; and calculating the offset value corresponding to the condition that both the first and second partial derivative functions are equal to 0 to obtain the optimal offset value. Calculating the offset value corresponding to the condition that both the first partial derivative function and the second partial derivative function are equal to 0, and obtaining the optimal offset value, includes: simultaneously performing elimination calculations when both the first partial derivative function and the second partial derivative function are equal to 0, to obtain an offset value relationship and a proportional coefficient relationship, wherein the offset value relationship does not contain the proportional coefficient, and the proportional coefficient relationship does not contain the offset value; calculating the average value of all the opening values ​​and the average value of all the pressure difference values, respectively, to obtain the average opening value and the average pressure difference value; substituting multiple opening values, multiple pressure difference values, the average opening value, and the average pressure difference value into the proportional coefficient relationship to calculate the optimal proportional coefficient; and substituting the optimal proportional coefficient, the average opening value, and the average pressure difference value into the offset value relationship to calculate the optimal offset value.

2. The method according to claim 1, characterized in that, Before acquiring the multiple opening values ​​and the corresponding differential pressure values, the method further includes: Acquire engine operating condition data, including fuel injection quantity, engine speed, and engine temperature; Determine whether each of the operating condition data meets the corresponding preset requirements, the preset requirements including the fuel injection quantity being greater than or equal to the fuel injection quantity threshold, the engine speed being greater than or equal to the engine speed threshold, and the engine temperature being within a predetermined temperature range; If any of the operating condition data fails to meet the corresponding preset requirement, the operating condition data continues to be acquired until all the operating condition data meet the corresponding preset requirement.

3. The method according to claim 2, characterized in that, Obtaining multiple opening values ​​and corresponding differential pressure values ​​includes: The EGR valve is controlled to adjust the opening value within the opening range and obtain the corresponding differential pressure value, resulting in multiple opening values ​​and corresponding differential pressure values. The opening range is the range of the opening values ​​corresponding to the EGR valve when the engine temperature is within a predetermined temperature range.

4. The method according to any one of claims 1 to 3, characterized in that, After substituting the multiple opening values ​​and the corresponding differential pressure values ​​into the variance function to calculate the optimal offset value, the method further includes: If the optimal offset value is greater than the offset threshold, the control issues a first fault alarm, which is used to indicate that the differential pressure flow meter has a zero-point drift fault.

5. The method according to any one of claims 1 to 3, characterized in that, After determining the flow rate of the exhaust pipe based on the corrected differential pressure value, the method further includes: The theoretical value of the exhaust gas flow rate corresponding to the corrected pressure difference value is obtained by referring to the exhaust gas flow rate lookup table. The exhaust gas flow rate lookup table is a lookup table of the pressure difference value, the opening value and the theoretical value of the exhaust gas flow rate. If the difference between the flow rate in the exhaust pipe and the theoretical value of the exhaust gas flow rate is greater than the error threshold, a second fault alarm is issued. The second fault alarm is used to remind the differential pressure flow meter of any fault other than zero-point drift. If the difference between the flow rate in the exhaust pipe and the theoretical value of the exhaust gas flow rate is less than or equal to the error threshold, the differential pressure flow meter is determined to be fault-free.

6. A flow correction device for a differential pressure flow meter, characterized in that, The differential pressure flow meter includes a differential pressure sensor and a throttling element. The throttling element is located on the exhaust pipe of the engine, and its cross-sectional area is smaller than that of the exhaust pipe. The differential pressure sensor monitors the pressure difference between the section of the exhaust pipe where the throttling element is located and other sections to determine the flow rate. An EGR valve is located on the exhaust pipe of the engine and on one side of the differential pressure flow meter. The device includes: The first determining unit is used to determine the correlation formula between the differential pressure value of the differential pressure sensor and the opening value of the EGR valve, wherein the correlation formula is that the differential pressure value is equal to the product of the opening value and the proportional coefficient plus the offset value; The first acquisition unit is used to acquire multiple opening values ​​and corresponding differential pressure values, wherein the opening value and the differential pressure value correspond one-to-one; The processing unit is used to process the correlation formula using the least squares method to obtain a variance function. The variance function is a function that calculates the variance of the two sides of the mathematical expression of the correlation formula. The unit substitutes multiple opening values ​​and the corresponding pressure difference values ​​into the variance function to calculate the optimal offset value. The optimal offset value is the offset value corresponding to the minimum function value of the variance function. The calculation unit is used to obtain the differential pressure value of the differential pressure sensor when the optimal offset value is less than or equal to the offset threshold, obtain the current differential pressure value, and calculate the difference between the current differential pressure value and the optimal offset value to obtain a corrected differential pressure value. The second determining unit is used to determine the flow rate of the exhaust pipe based on the corrected pressure difference value; The processing unit includes: a first processing module, which uses the partial derivative method to find the partial derivative of the proportional coefficient with respect to the expression of the variance function to obtain a first partial derivative function; a second processing module, which uses the partial derivative method to find the partial derivative of the offset value with respect to the expression of the variance function to obtain a second partial derivative function; and a calculation module, which calculates the offset value corresponding to the case where both the first partial derivative function and the second partial derivative function are equal to 0, to obtain the optimal offset value. The calculation module includes: a processing submodule, which performs simultaneous elimination calculations when both the first partial derivative function and the second partial derivative function are equal to 0, to obtain an offset value relationship and a proportional coefficient relationship, wherein the offset value relationship does not contain the proportional coefficient and the proportional coefficient relationship does not contain the offset value; a first calculation submodule, which calculates the average value of all the opening values ​​and the average value of all the pressure difference values, to obtain the average opening value and the average pressure difference; a second calculation submodule, which substitutes multiple opening values, multiple pressure difference values, the average opening value, and the average pressure difference value into the proportional coefficient relationship to calculate the optimal proportional coefficient; and a third calculation submodule, which substitutes the optimal proportional coefficient, the average opening value, and the average pressure difference value into the offset value relationship to calculate the optimal offset value.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 5.

8. A differential pressure flow meter management system, characterized in that, include: A differential pressure flow meter, one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing any one of claims 1 to 5.

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