Diesel engine nitrogen and oxygen emission standard reaching prediction method, system, equipment and medium

Abstract

The invention discloses a diesel engine nitrogen and oxygen emission standard reaching prediction method, system and device and a medium. The method comprises the steps that S1, a WNTE control area and a grid are determined; s2, collecting early-stage test data of the engine, and dividing the early-stage test data into each subarea according to the determined control area; s3, collecting nitrogen-oxygen conversion rate data of the post-treatment SCR catalyst at different temperatures; s4, the nitrogen-oxygen conversion rate of each partition of the WNTE is calculated; and S5, calculating the predicted nitrogen and oxygen emission value of each partition, and judging whether the emission reaches the standard or not. According to the method, the nitrogen-oxygen conversion rate and engine original emission data can be obtained in a product design stage and used for calculating WNTE cyclic emission data, whether an aftertreatment system can guarantee that emission reaches the standard or not can be predicted in advance in the design stage, model selection and design of aftertreatment products can be optimized in an earlier research and development stage, unnecessary test resources and time loss are reduced, and the economic benefit is improved. And the product research and development efficiency is improved.

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 emission limits and measurement methods of pollutants for heavy-duty diesel vehicles stipulate that when the engine model undergoes type inspection, the test items required include standard cycles and non-standard cycles. Among them, the standard cycle includes steady-state operating conditions WHSC and transient operating conditions WHTC, and the non-standard cycle includes the engine bench non-standard cycle WNTE and the vehicle-mounted PEMS test. At present, there are many methods and technologies for calculating and predicting the nitrogen oxide conversion rate of the standard cycle and the vehicle-mounted method, but there is little research on the engine bench non-standard cycle WNTE. The mass ratio emission of conventional pollutants is determined based on the test points randomly distributed in the WNTE control area. The WNTE cycle divides the control area into 9 or 12 grids, and all test points are located in 3 random grids in the control area. Because the WNTE cycle test points are random, when the emission level of the selected point is poor, there is a great risk of non-compliance with the nitrogen oxides. In addition, the industry only conducts WNTE cycle tests on engine benches, and there is no special calculation scheme for calculating or predicting the WNTE cycle nitrogen oxide conversion rate.

[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 the standards, so as to solve the above-mentioned problems.

[0005] On the one hand, the present application provides a method for predicting whether nitrogen oxide emissions of 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 test data of the engine, 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; step S5: calculating the predicted nitrogen oxide emission value of each partition, and determining whether the emission meets standards.

[0006] In one implementation of the present application, the 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 includes: engine speed, torque, SCR temperature, NO X The original exhaust of the mass ratio; wherein the original exhaust refers to the original pollutant emissions 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 a small sample test bench test, and a small sample of SCR catalyst is taken and tested in a 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 can meet 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, the system comprising: a network calculation unit, used to determine the WNTE control area and grid; a network division unit, 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, used to collect nitrogen oxide conversion rate data at different temperatures of the post-treatment SCR catalyst; a conversion rate calculation unit, used to calculate the nitrogen oxide conversion rate of each WNTE partition; an emission compliance judgment unit, used to calculate the predicted nitrogen oxide emission value of each partition, and judge whether the emission meets the standard.

[0013] In the third aspect, the present application also provides a diesel engine nitrogen oxide emission compliance prediction device, 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: 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 oxide conversion rate data of the post-treatment SCR catalyst at different temperatures; step S4: calculate the nitrogen oxide conversion rate of each WNTE partition; step S5: calculate the predicted nitrogen oxide emission value of each partition, and determine whether the emission meets the standard.

[0014] In a fourth aspect, a non-volatile computer storage medium for predicting compliance of nitrogen oxide emissions of 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-processing 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.

[0015] The present application provides a method, system, device and medium for predicting compliance of nitrogen oxide emissions from diesel engines. The method uses nitrogen oxide conversion rate and original engine emission data that can be obtained in the product design stage to calculate WNTE cycle emission data. It can predict in advance in the design stage whether the after-treatment system can ensure that the emissions meet the standards. It can optimize the selection and design of after-treatment products at an earlier research and development stage, reduce unnecessary test 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 the present application;

[0019] Figure 3A composition diagram 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 oxide emission compliance prediction device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present 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 solution proposed in the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0023] Figure 1 A flow chart of a method for predicting the compliance of nitrogen and oxygen emissions from a diesel engine 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, according to the WNTE control area division requirements, the engine speed range and the engine torque range are calculated; according to the grid division requirements, the grid boundary line is calculated to divide the WNTE control area 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 original emission is the original emission of pollutants when there is no aftertreatment 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 As shown in the figure, there are 9 networks and 122 sets of data.

[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 the embodiment of the present application, the calculation method is: according to the temperature points in the data obtained in step S3, the temperature is divided into zones. For example, the data obtained in step S3 are as shown in the first and second columns of Table 1 below, and 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) means 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 of each partition in step S2 are classified according to the temperature partition. For example, the data processing of partition 1 is as shown in Table 2 below. The second column is the number of SCR temperatures in each temperature partition for a total of 16 data points in partition 1, and the third column is the proportion of the number of data points in each partition. For example, the number of data points in the temperature partition [225, 275) is 1, and the proportion of data points 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, the weighted nitrogen-oxygen conversion rate of each partition is calculated. The weighted nitrogen-oxygen conversion rate of 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 shown in Table 3 below:

[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 the embodiment of the present application, the maximum nitrogen and oxygen mass ratio of each partition is multiplied by the nitrogen and oxygen conversion rate of each corresponding partition to obtain the predicted nitrogen and oxygen emission value of the partition. The maximum value of the predicted nitrogen and oxygen emission value of each partition is compared with the regulatory emission limit to determine whether the emission meets 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 are usually data of a fresh catalyst. The predicted results according to the method described in the present invention are 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] The embodiment of the present application calculates the predicted nitrogen oxide emission values ​​and compliance risks of all WNTE partitions, but in fact, for a certain series of engines, only a few fixed partitions have a greater risk of non-compliance with emissions. Only the compliance of high-risk partitions can be calculated to reduce the amount of calculation. In addition, the early engine test data collected in step S2 can also be replaced with calibration data during the engine development calibration process.

[0044] The above is a diesel engine nitrogen oxide emission compliance prediction method 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 oxide emission compliance prediction system. Figure 3 A composition diagram of a diesel engine nitrogen and oxygen emission compliance prediction system provided in an embodiment of the present application, such as 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 the 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 the nitrogen oxygen 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 oxygen conversion rate of each WNTE partition; an emission compliance judgment unit 305, which is used to calculate the predicted nitrogen oxygen emission value of each partition and judge whether the emission meets the standard.

[0045] The above is a diesel engine nitrogen oxide emission compliance 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 oxide emission compliance prediction device. Figure 4 A schematic diagram of a diesel engine nitrogen and oxygen emission compliance prediction device provided in an embodiment of the present application, such as Figure 4As shown, the device mainly includes: at least one processor 401; and a memory 402 that is communicatively connected to 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: step S1: determining the WNTE control area and grid; step S2: collecting preliminary test data of the engine, 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 partition of the WNTE; 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 compliance of nitrogen oxide emissions of a diesel engine, storing computer executable instructions, which are executed by a processor to implement: Step S1: Determine the WNTE control area and grid; Step S2: Collect preliminary engine test data, and divide the preliminary test data into each partition according to the determined control area; Step S3: Collect nitrogen oxide conversion rate data of the post-treatment SCR catalyst at different temperatures; Step S4: Calculate the nitrogen oxide conversion rate of each partition of the WNTE; Step S5: Calculate the predicted nitrogen oxide emission value of each partition, and determine whether the emission meets the standard.

[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 flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, 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 flowchart and / or block diagram. 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 capable of directing a computer or other programmable data processing device to operate 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 A 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 operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

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

[0051] Each embodiment in this application is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0052] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0053] The above is only 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 modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for predicting whether nitrogen oxide emissions from diesel engines 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: 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.

2. A diesel engine nitrogen oxide emission compliance prediction method 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. A diesel engine nitrogen oxide emission compliance prediction method according to claim 1, characterized in that: In step S2, the preliminary test data specifically includes: engine speed, torque, SCR temperature, NO X The original exhaust of the mass ratio; wherein the original exhaust refers to the original pollutant emissions of the engine when there is no after-treatment system.

4. A diesel engine nitrogen oxide emission compliance prediction method according to claim 1, characterized in that: In step S3, the specific source of the nitrogen oxide conversion rate data is: provided by the catalyst manufacturer or obtained through a small sample test bench test, and a small sample of SCR catalyst is taken and tested in a laboratory to obtain the nitrogen oxide conversion rate data.

5. A diesel engine nitrogen oxide emission compliance prediction method according to claim 1, characterized in that: The step S4 specifically includes: Step S41: partition 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: Calculate the weighted nitrogen oxygen conversion rate of each partition.

6. A diesel engine nitrogen oxide emission compliance prediction method according to claim 1, characterized in that: The step S5 specifically includes: The predicted nitrogen oxide emission value of each partition is obtained by multiplying the maximum nitrogen oxide mass ratio of each partition by the nitrogen oxide conversion rate of each partition; Compare the maximum predicted nitrogen oxide emission value for each zone with the regulatory emission limit to determine whether the emission meets the standard.

7. A diesel engine nitrogen oxide emission compliance prediction method according to claim 2, characterized in that: The WNTE control area is divided into 9 grids.

8. A diesel engine nitrogen oxide emission compliance prediction system, characterized in that: The system comprises: Network computing unit, used to determine WNTE control areas and grids; A network partitioning unit, used for collecting engine preliminary test data and dividing the preliminary test data into each partition according to the determined control area; A collection unit, used to collect nitrogen oxide conversion rate data of the post-treatment SCR catalyst at different temperatures; A 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 oxide emission value of each partition and judge whether the emission meets the standard.

9. A diesel engine nitrogen oxide emission compliance prediction device, 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 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.

10. A non-volatile computer storage medium for predicting the compliance of diesel engine nitrogen and oxygen emissions, 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.

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