A method, system, device and medium for predicting nitrogen oxide emission compliance of a diesel engine

Abstract

The application discloses a diesel engine nitrogen and oxygen emission standard reaching prediction method, system, equipment and medium, and the method comprises the following steps: step S1: determining a WNTE control region and a grid; step S2: collecting engine early test data, and dividing the early test data into each subarea according to the determined control region; step S3: collecting nitrogen and oxygen conversion rate data of an aftertreatment SCR catalyst at different temperatures; step S4: calculating the nitrogen and oxygen conversion rate of each subarea of the WNTE; step S5: calculating a predicted nitrogen and oxygen emission value of each subarea, and judging whether the emission reaches a standard. Nitrogen and oxygen conversion rates and engine original emission data can be obtained in a product design stage, are used for calculating WNTE cycle emission data, can predict whether an aftertreatment system can guarantee that the emission reaches a standard in an early design stage, can optimize selection and design of an aftertreatment product in an earlier research and development stage, reduce unnecessary test resources and time loss, and improve product research and development efficiency.

Description

Technical Field

[0001] The present application relates to the field of vehicle emission testing technology, and in particular to a method, system, equipment and medium for predicting compliance of nitrogen and oxygen emissions from diesel engines. Background Art

[0002] The heavy-duty diesel vehicle pollutant emission limits and measurement methods specify the required test items for engine type inspection, including standard and non-standard cycles. Standard cycles include the steady-state (WHSC) and transient (WHTC) cycles, while non-standard cycles include the engine bench non-standard cycle (WNTE) and vehicle-mounted PEMS testing. Currently, there are numerous methods and techniques for calculating and predicting NOx conversion rates using standard and vehicle-mounted tests, but little research exists on the engine bench non-standard cycle (WNTE). Mass-specific emissions of conventional pollutants are determined based on randomly distributed test points within the WNTE control area. The WNTE cycle divides the control area into 9 or 12 grids, with all test points located within three random grids within the control area. Because WNTE test points are randomly selected, poor emission levels at selected points can lead to a significant risk of non-compliance with NOx standards. Furthermore, the industry only conducts WNTE cycle testing on engine benches, and there is no dedicated calculation or prediction method for WNTE cycle NOx conversion rates.

[0003] Therefore, it is necessary to perform predictive calculations on WNTE cycle nitrogen oxide emissions during the post-processing R&D, design, and selection stages, conduct targeted optimization and upgrades in a timely manner, reduce unnecessary test resources and time loss, and improve product R&D efficiency. Summary of the Invention

[0004] The present application provides a method, system, device and medium for predicting whether nitrogen and oxygen emissions of a diesel engine meet standards, in order to solve the above-mentioned problems.

[0005] On the one hand, the present application provides a method for predicting whether nitrogen oxide emissions from a diesel engine meet standards, the method comprising the following steps: step S1: determining a WNTE control area and a grid; step S2: collecting preliminary engine test data, and dividing the preliminary test data into each partition according to the determined control area; step S3: collecting nitrogen oxide conversion rate data at different temperatures of a post-treatment SCR catalyst; step S4: calculating the nitrogen oxide conversion rate of each WNTE partition; step S5: calculating the predicted nitrogen oxide emission value for each partition, and determining whether the emissions meet standards.

[0006] In one implementation of the present application, step S1 specifically includes: calculating the engine speed range and the engine torque range according to the WNTE control area division requirements; calculating the grid boundary line according to the grid division requirements, and dividing the WNTE control area into a plurality of grids.

[0007] In one implementation of the present application, in step S2, the preliminary test data specifically include: engine speed, torque, SCR temperature, NO X The original exhaust of the mass ratio; wherein the original exhaust is the original pollutant emission of the engine when there is no after-treatment system.

[0008] In one implementation of the present application, in step S3, the specific source of the nitrogen oxide conversion rate data is: provided by the catalyst manufacturer or obtained through small sample test bench testing, and a small sample of SCR catalyst is taken and tested in the laboratory to obtain the nitrogen oxide conversion rate data.

[0009] In one implementation of the present application, the step S4 specifically includes: step S41: partitioning the temperature according to the temperature points of the data obtained in step S3; step S42: classifying the data points of each partition in step S2 according to the temperature partition; step S43: calculating the weighted nitrogen oxygen conversion rate of each partition.

[0010] In one implementation of the present application, step S5 specifically includes: multiplying the maximum nitrogen oxide mass ratio of each partition by the nitrogen oxide conversion rate of each corresponding partition to obtain the predicted nitrogen oxide emission value of the partition; comparing the maximum value of the predicted nitrogen oxide emission value of each partition with the regulatory emission limit to determine whether the emission meets the standard.

[0011] In one implementation of the present application, the WNTE control area is divided into 9 grids.

[0012] In the second aspect, the present application also provides a diesel engine nitrogen oxide emission compliance prediction system, which includes: a network calculation unit for determining the WNTE control area and grid; a network division unit for collecting engine preliminary test data and dividing the preliminary test data into each partition according to the determined control area; a collection unit for collecting nitrogen oxide conversion rate data at different temperatures of the post-treatment SCR catalyst; a conversion rate calculation unit for calculating the nitrogen oxide conversion rate of each WNTE partition; and an emission compliance judgment unit for calculating the predicted nitrogen oxide emission value of each partition and judging whether the emission meets the standard.

[0013] In a third aspect, the present application also provides a device for predicting whether nitrogen oxide emissions from a diesel engine meet standards, the device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can complete: step S1: determining the WNTE control area and grid; step S2: collecting preliminary engine test data, and dividing the preliminary test data into each partition according to the determined control area; step S3: collecting nitrogen oxide conversion rate data of the post-treatment SCR catalyst at different temperatures; step S4: calculating the nitrogen oxide conversion rate of each WNTE partition; step S5: calculating the predicted nitrogen oxide emission value of each partition, and determining whether the emission meets the standard.

[0014] In a fourth aspect, a non-volatile computer storage medium for predicting compliance of nitrogen oxide emissions from a diesel engine stores computer-executable instructions, wherein the computer-executable instructions are executed by a processor to implement: step S1: determining a WNTE control area and a grid; step S2: collecting preliminary engine test data, and dividing the preliminary test data into each partition according to the determined control area; step S3: collecting nitrogen oxide conversion rate data of a post-treatment SCR catalyst at different temperatures; step S4: calculating the nitrogen oxide conversion rate of each WNTE partition; and step S5: calculating the predicted nitrogen oxide emission value for each partition, and determining whether the emission meets the standard.

[0015] The present application provides a method, system, device and medium for predicting whether a diesel engine's nitrogen and oxygen emissions meet standards. The method uses nitrogen and oxygen conversion rates and engine raw emission data, which can be obtained during the product design phase, to calculate WNTE cycle emission data. This method can predict in advance during the design phase whether the aftertreatment system can ensure emission compliance. It can optimize the selection and design of aftertreatment products at an earlier stage of research and development, reduce unnecessary experimental resources and time loss, and improve product research and development efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A flow chart of a method for predicting compliance of nitrogen and oxygen emissions from a diesel engine provided in an embodiment of the present application;

[0018] Figure 2 WNTE control area partition and data statistics provided in the embodiment of this application;

[0019] Figure 3A diagram showing the composition of a diesel engine nitrogen and oxygen emission compliance prediction system provided in an embodiment of the present application;

[0020] Figure 4 A schematic diagram of a diesel engine nitrogen and oxygen emission compliance prediction device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0022] The embodiments of the present application provide a method, system, device and medium for predicting compliance of nitrogen and oxygen emissions from a diesel engine. The technical solutions proposed in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0023] Figure 1 This is a flow chart of a method for predicting the compliance of nitrogen and oxygen emissions from diesel engines provided in an embodiment of the present application. Figure 1 As shown, the method mainly includes the following steps:

[0024] Step S1: Determine the WNTE control area and grid.

[0025] In the embodiment of the present application, the engine speed range and the engine torque range are calculated according to the WNTE control area division requirements; according to the grid division requirements, the grid boundary lines are calculated, and the WNTE control area is divided into 9 or 12 grids.

[0026] Step S2: Collecting engine preliminary test data, and dividing the preliminary test data into each partition according to the determined control area.

[0027] In the embodiment of the present application, the collected test data include: engine speed, torque, SCR temperature, NO X The mass ratio is the original exhaust; the original exhaust refers to the original pollutant emissions of the engine without the after-treatment system. It is necessary to ensure that each partition has data. For example, the WNTE control area and partition determined in step S1 and the 122 sets of data obtained in step S2 are as follows: Figure 2 There are 9 networks and 122 sets of data in the figure.

[0028] Step S3: collecting nitrogen oxide conversion rate data of the post-processing SCR catalyst at different temperatures.

[0029] In the embodiments of the present application, the nitrogen oxide conversion rate data has multiple sources: first, the nitrogen oxide conversion rate at different temperatures is the most important product performance of the SCR catalyst, which has been determined in the catalyst design stage and can be provided by the catalyst manufacturer; second, it can be obtained through small sample test bench testing, taking a small sample of the SCR catalyst and testing it in the laboratory; third, it can be obtained by testing according to the method provided by the existing catalytic performance evaluation method.

[0030] Step S4: Calculate the nitrogen-oxygen conversion rate of each WNTE partition.

[0031] In this embodiment of the present application, the calculation method is as follows: based on the temperature points in the data obtained in step S3, the temperature is divided into zones. For example, if the data obtained in step S3 is shown in the first and second columns of Table 1 below, the temperature zone is the third column, and the boundary value of the temperature zone is the middle value of the adjacent temperature, where [225,275) indicates that the temperature is greater than or equal to 225°C and less than 275°C.

[0032] Table 1 Nitrogen Oxygen Conversion Rate

[0033] Temperature (℃) Nitrogen oxygen conversion rate (%) Temperature zone (℃) 200 90 [180,225) 250 98 [225,275) 300 98 [275,325) 350 96 [325,375) 400 94 [375,425) 450 92 [425,475) 500 89 >475

[0034] Then, the data points in each partition in step S2 are classified by temperature partition. For example, the data processing for partition 1 is shown in Table 2 below. The second column shows the number of SCR temperatures in each temperature partition for the total 16 data points in partition 1, and the third column shows the percentage of data points in each partition. For example, the number of data points in the temperature partition [225, 275) is 1, and the data point percentage is 1 / 16 = 0.0625.

[0035] Table 2 Temperature partition table of data points

[0036] Temperature zone (℃) Number of data points Data point ratio [180,225) 0 0 [225,275) 1 0.0625 [275,325) 5 0.3125 [325,375) 8 0.5 [375,425) 2 0.125 [425,475) 0 0 >475 0 0 total 16 1

[0037] Finally, calculate the weighted nitrogen-oxygen conversion rate for each partition. The weighted nitrogen-oxygen conversion rate for each partition is equal to the sum of the product of the data point proportion of all temperature partitions and the nitrogen-oxygen conversion rate of the partition. As shown in Tables 1 and 2 above, for partition 1, the calculation method is as follows in Table 3:

[0038] Table 3 Calculation table of nitrogen and oxygen conversion rate

[0039]

[0040] Step S5: Calculate the predicted nitrogen oxide emission value for each partition and determine whether the emission meets the standard.

[0041] In this embodiment, the predicted nitrogen oxide emissions for each zone are calculated by multiplying the maximum nitrogen oxide mass ratio of each zone by the nitrogen oxide conversion rate for that zone. Comparing the maximum predicted nitrogen oxide emission value for each zone with the regulatory emission limit determines whether the emissions meet the standard.

[0042] In an embodiment of the present application, the SCR temperature in step S2 can be the SCR carrier temperature, or the airflow temperature near the front / rear end face of the SCR. When calculating the predicted nitrogen oxide emission value of each partition in step S5, the maximum nitrogen oxide mass ratio of each partition is selected. The average value of all data points can also be calculated here instead. The nitrogen oxide conversion rate data at different temperatures of the post-treatment SCR catalyst collected in step S3 is usually the data of a fresh catalyst. The predicted result according to the method of the present invention is also for the state of the fresh sample. If it is necessary to predict the emission compliance of the post-treatment under a specific durability state, the nitrogen oxide conversion rate data of the corresponding state can be collected for calculation.

[0043] While this embodiment calculates predicted NOx emissions and compliance risks for all WNTE zones, in reality, for a given engine series, only a few zones may have a high risk of non-compliance. Compliance can be calculated for only the high-risk zones to reduce the computational effort. Furthermore, the preliminary engine test data collected in step S2 can be replaced with calibration data from the engine development and calibration process.

[0044] The above is a method for predicting the compliance of nitrogen and oxygen emissions from a diesel engine provided by an embodiment of the present application. Based on the same inventive concept, an embodiment of the present application also provides a system for predicting the compliance of nitrogen and oxygen emissions from a diesel engine. Figure 3 A composition diagram of a diesel engine nitrogen and oxygen emission compliance prediction system provided in an embodiment of the present application is shown in FIG. Figure 3 As shown, the system mainly includes: a network calculation unit 301, which is used to determine the WNTE control area and grid; a network division unit 302, which is used to collect engine preliminary test data and divide the preliminary test data into each partition according to the determined control area; a collection unit 303, which is used to collect nitrogen oxide conversion rate data of the post-treatment SCR catalyst at different temperatures; a conversion rate calculation unit 304, which is used to calculate the nitrogen oxide conversion rate of each WNTE partition; and an emission compliance judgment unit 305, which is used to calculate the predicted nitrogen oxide emission value of each partition and judge whether the emission meets the standard.

[0045] The above is a diesel engine nitrogen and oxygen emission standard prediction system provided by the embodiment of the present application. Based on the same inventive concept, the embodiment of the present application also provides a diesel engine nitrogen and oxygen emission standard prediction device. Figure 4 A schematic diagram of a diesel engine nitrogen and oxygen emission standard prediction device provided in an embodiment of the present application is shown as follows: Figure 4As shown, the device mainly includes: at least one processor 401; and a memory 402 in communication with the at least one processor; wherein the memory 402 stores instructions that can be executed by the at least one processor 401, and the instructions are executed by the at least one processor 401 so that the at least one processor 401 can complete the following: step S1: determining the WNTE control area and grid; step S2: collecting engine preliminary test data, and dividing the preliminary test data into each partition according to the determined control area; step S3: collecting nitrogen oxide conversion rate data of the post-treatment SCR catalyst at different temperatures; step S4: calculating the nitrogen oxide conversion rate of each WNTE partition; step S5: calculating the predicted nitrogen oxide emission value of each partition, and judging whether the emission meets the standard.

[0046] In addition, an embodiment of the present application also provides a non-volatile computer storage medium for predicting whether a diesel engine's nitrogen and oxygen emissions meet standards, storing computer-executable instructions, which are executed by a processor to implement: Step S1: Determine the WNTE control area and grid; Step S2: Collect engine preliminary test data, and divide the preliminary test data into each partition according to the determined control area; Step S3: Collect nitrogen and oxygen conversion rate data at different temperatures of the post-treatment SCR catalyst; Step S4: Calculate the nitrogen and oxygen conversion rate of each WNTE partition; Step S5: Calculate the predicted nitrogen and oxygen emission value for each partition, and determine whether the emissions meet the standards.

[0047] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0048] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0049] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0050] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0051] The various embodiments in this application are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences from other embodiments. In particular, the device embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the partial description of the method embodiments.

[0052] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0053] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for predicting whether a diesel engine's nitrogen and oxygen emissions meet standards, characterized in that: The method comprises the following steps: Step S1: Determine the WNTE control area and grid; Step S2: collecting engine preliminary test data, and dividing the preliminary test data into each partition according to the determined control area; Step S3: collecting nitrogen oxide conversion rate data of the post-processing SCR catalyst at different temperatures; Step S4: Calculating the nitrogen-oxygen conversion rate of each WNTE partition; specifically comprising: Step S41: Partitioning the temperature according to the temperature points of the data obtained in Step S3; Step S42: Classifying the data points of each partition in Step S2 according to the temperature partition; Step S43: Calculating the weighted nitrogen-oxygen conversion rate of each partition; Step S5: Calculate the predicted nitrogen oxide emission value for each partition and determine whether the emission meets the standard; specifically, multiply the maximum nitrogen oxide mass ratio of each partition by the nitrogen oxide conversion rate of each partition to obtain the predicted nitrogen oxide emission value of the partition; compare the maximum value of the predicted nitrogen oxide emission value of each partition with the regulatory emission limit to determine whether the emission meets the standard.

2. A method for predicting compliance of nitrogen oxide emissions from a diesel engine according to claim 1, characterized in that: The step S1 specifically includes: Calculate the engine speed range and engine torque range according to the WNTE control area division requirements; According to the grid division requirements, the grid boundary lines are calculated and the WNTE control area is divided into several grids.

3. The method for predicting whether nitrogen oxide emissions from a diesel engine meet standards according to claim 1, wherein: In step S2, the preliminary test data specifically include: engine speed, torque, SCR temperature, NO X The original exhaust of the mass ratio; wherein the original exhaust is the original pollutant emission of the engine when there is no after-treatment system.

4. The method for predicting whether nitrogen oxide emissions from a diesel engine meet standards according to claim 1, wherein: In step S3, the specific source of the nitrogen oxide conversion rate data is: provided by the catalyst manufacturer or obtained through small sample test bench testing, and the nitrogen oxide conversion rate data is obtained by taking a small sample of SCR catalyst and testing it in the laboratory.

5. The method for predicting whether nitrogen oxide emissions from a diesel engine meet standards according to claim 2, wherein: The WNTE control area is divided into 9 grids.

6. A diesel engine nitrogen oxide emission compliance prediction system, applied to a diesel engine nitrogen oxide emission compliance prediction method according to any one of claims 1 to 5, characterized in that: The system comprises: Network computing unit, used to determine the WNTE control area and grid; A network partitioning unit, configured to collect engine preliminary test data and divide the preliminary test data into each partition according to a determined control area; A collection unit is used to collect nitrogen oxide conversion rate data at different temperatures of the post-treatment SCR catalyst; Conversion rate calculation unit, used to calculate the nitrogen and oxygen conversion rate of each WNTE partition; The emission compliance judgment unit is used to calculate the predicted nitrogen and oxygen emission values ​​of each partition and judge whether the emissions meet the standards.

7. A device for predicting whether nitrogen and oxygen emissions from a diesel engine meet standards, applied to a method for predicting whether nitrogen and oxygen emissions from a diesel engine meet standards according to any one of claims 1 to 5, characterized in that: The device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that are executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to complete: Step S1: Determine the WNTE control area and grid; Step S2: collecting engine preliminary test data, and dividing the preliminary test data into each partition according to the determined control area; Step S3: collecting nitrogen oxide conversion rate data of the post-processing SCR catalyst at different temperatures; Step S4: Calculate the nitrogen-oxygen conversion rate of each WNTE partition; Step S5: Calculate the predicted nitrogen oxide emission value for each partition and determine whether the emission meets the standard.

8. A non-volatile computer storage medium for predicting nitrogen and oxygen emissions compliance of a diesel engine, applied to a method for predicting nitrogen and oxygen emissions compliance of a diesel engine according to any one of claims 1 to 5, storing computer-executable instructions, characterized in that: The computer executable instructions are executed by a processor to implement: Step S1: Determine the WNTE control area and grid; Step S2: collecting engine preliminary test data, and dividing the preliminary test data into each partition according to the determined control area; Step S3: collecting nitrogen oxide conversion rate data of the post-processing SCR catalyst at different temperatures; Step S4: Calculate the nitrogen-oxygen conversion rate of each WNTE partition; Step S5: Calculate the predicted nitrogen oxide emission value for each partition and determine whether the emission meets the standard.

Images