Method, device, storage medium and electronic device for determining engine NOx emission value

Abstract

The present application provides a method, device, storage medium, and electronic device for determining an engine NOx emission value. The method comprises: obtaining a current NOx mass measurement value; obtaining a measurement deviation value, wherein the measurement deviation value is the sum of the current actual NH3 emission value and a preset NOx mass average value, and the current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value; and determining the current actual NOx emission value based on the current NOx mass measurement value and the measurement deviation value, wherein the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value. The present application improves the control accuracy of the NOx closed loop by accurately calculating the actual NH3 emission value under the current operating conditions, thereby ensuring performance indicators such as engine emissions and economy, and solving the problem of inaccurate NOx actual value calculation caused by NH3 cross-sensitivity and NOx sensor signal aging drift in the prior art.

Description

Technical Field

[0001] The present application relates to the field of engines, and in particular, to a method for determining an engine NOx emission value, an apparatus for determining an engine NOx emission value, a readable storage medium, and an electronic device. Background Art

[0002] China VI natural gas engines using stoichiometric combustion technology emit almost no NH3 in their original exhaust. However, after chemical reactions within the catalyst, a significant amount of NH3 is produced in the tailpipe. Currently, the NOx sensors used in engine exhaust pipes are primarily electrochemical sensors, which suffer from NH3 cross-sensitivity. This means that the NOx mass measurement collected by the NOx sensor cannot accurately distinguish between true NOx and NH3. Therefore, if the catalytic converter emits excessive NH3, the measurement result of the downstream NOx sensor will be higher than the actual value. Under the closed-loop control strategy, the system deems the NOx emissions downstream of the catalytic converter excessive, resulting in an abnormal correction of the fuel injection amount, which in turn leads to more severe downstream NH3 emissions, creating a vicious cycle. Furthermore, NOx sensors can experience signal drift or aging over time, leading to inaccurate signal acquisition. Furthermore, varying exhaust temperatures, air-fuel ratios, and catalyst state vary in the efficiency of the chemical reactions within the catalyst, causing variations in NH3 emissions in the tailpipe. This in turn leads to inaccurate calculations of the actual NOx value, impacting engine control. Summary of the Invention

[0003] The main purpose of this application is to provide a method for determining the NOx emission value of an engine, a device for determining the NOx emission value of an engine, a readable storage medium and an electronic device, so as to at least solve the problem in the prior art of inaccurate calculation of the actual NOx value due to cross-sensitivity of NH3 and aging drift of the NOx sensor signal.

[0004] To achieve the above-mentioned objective, according to one aspect of the present application, a method for determining an engine NOx emission value is provided, comprising: obtaining a current NOx mass measurement value, the current NOx mass measurement value being a measurement value of the NOx mass in the final emissions of the engine under the current operating condition, the final emissions being the engine emissions after post-treatment purification; obtaining a measurement deviation value, the measurement deviation value being the sum of a current actual NH3 emission value and a preset NOx mass average value, the preset NOx mass average value being the average value of a plurality of preset NOx mass measurement values ​​corresponding to a plurality of fuel cut-off conditions within a first preset time period before a current moment, the preset NOx mass measurement values ​​corresponding one-to-one to the fuel cut-off conditions, the current actual NH3 emission value being obtained by correcting a current theoretical NH3 emission value, the current actual NH3 emission value representing the actual NH3 emission value of the engine under the current operating condition, the current theoretical NH3 emission value being the theoretical emission value of the engine under the current operating condition; and determining a current actual NOx emission value based on the current NOx mass measurement value and the measurement deviation value, the actual NOx emission value being the difference between the NOx mass measurement value and the measurement deviation value.

[0005] Optionally, before obtaining the measurement deviation value, the method also includes: obtaining the current speed and current intake pressure of the engine under the current operating conditions; obtaining a first mapping relationship, wherein the first mapping relationship is used to represent the mapping relationship between the speed of the engine, the intake pressure of the engine and the theoretical NH3 emission value; and determining, based on the current speed of the engine, the current intake pressure of the engine and the first mapping relationship, that the theoretical NH3 emission value corresponding to the current speed of the engine and the current intake pressure of the engine is the current theoretical NH3 emission value.

[0006] Optionally, before obtaining the measurement deviation value, the method also includes: obtaining the current air-fuel ratio of the engine and the current exhaust temperature of the engine; obtaining a second mapping relationship, wherein the second mapping relationship is used to represent the mapping relationship between the air-fuel ratio of the engine, the exhaust temperature of the engine and the NH3 emission correction value; and determining the NH3 emission correction value corresponding to the current air-fuel ratio of the engine and the current exhaust temperature of the engine as the current NH3 emission correction value based on the current air-fuel ratio of the engine, the current exhaust temperature of the engine and the second mapping relationship, wherein the current NH3 emission correction value is used to correct the current theoretical NH3 emission value.

[0007] Optionally, before obtaining the measurement deviation value, the method further includes: obtaining a current aging factor of a reaction catalyst, the reaction catalyst being used to catalyze chemical reactions of various types of emissions in the original emissions of the engine, the original emissions being engine emissions that have not been post-processed and purified; obtaining a first preset array, the first preset array being used to represent a mapping relationship between the aging factor of the reaction catalyst and the NH3 correction factor; determining, based on the current aging factor of the reaction catalyst and the first preset array, the NH3 correction factor corresponding to the current aging factor of the reaction catalyst as the current NH3 correction factor; and correcting the current theoretical NH3 emission value using the current NH3 emission correction value and the current NH3 correction factor to obtain the actual NH3 emission value, the actual NH3 emission value being the product of a target value and the current NH3 correction factor, and the target value being the sum of the current theoretical NH3 emission value and the current NH3 emission correction value.

[0008] Optionally, a first preset time period includes multiple fuel cut-off conditions. Before obtaining the measurement deviation value, the method further includes: obtaining the exhaust gas discharge time under each of the fuel cut-off conditions within the first preset time period, the exhaust gas discharge time being the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off condition; obtaining the preset NOx mass measurement value under each of the fuel cut-off conditions within the first preset time period after the engine starts to enter the fuel cut-off condition and the exhaust gas discharge time has passed, to obtain multiple preset NOx mass measurement values; calculating the average value of the multiple preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value; determining the preset NOx mass average value based on the relationship between the multiple preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

[0009] Optionally, the preset NOx mass average value is determined based on the size relationship between multiple preset NOx mass measurement values ​​and the first initial NOx mass average value within the first preset time period, including: obtaining multiple difference values, one difference value is the difference between one preset NOx mass measurement value and the first initial NOx mass average value; when multiple difference values ​​are all less than or equal to the preset difference value, determining the first initial NOx mass average value as the preset NOx mass average value; when at least one difference value is greater than the preset difference value, determining the second initial NOx mass average value obtained within a second preset time period as the preset NOx mass average value within the first preset time period, and the second preset time period is before the first preset time period.

[0010] Optionally, obtaining the exhaust gas discharge time under each of the fuel cut-off conditions within the first preset time period includes: obtaining the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period; obtaining a second preset array, the second preset array being used to represent the mapping relationship between the speed of the engine under each of the fuel cut-off conditions within the first preset time period and the exhaust gas discharge time; and determining, based on the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period and the second preset array, a plurality of exhaust gas discharge times corresponding to the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period as the exhaust gas discharge time under each of the fuel cut-off conditions.

[0011] According to another aspect of the present application, a method and apparatus for determining an engine NOx emission value is provided, comprising: a first acquisition unit for acquiring a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating condition, wherein the final emissions are the engine emissions after post-processing purification; a second acquisition unit for acquiring a measurement deviation value, wherein the measurement deviation value is the sum of the current actual NH3 emission value and a preset NOx mass average value, wherein the preset NOx mass average value is a plurality of preset NOx mass average values ​​corresponding to a plurality of fuel cut-off operating conditions within a first preset time period before the current moment. Assume an average value of the NOx mass measurement value, the preset NOx mass measurement value corresponds one-to-one to the fuel cut-off operating condition, the current NH3 actual emission value is obtained by correcting the current NH3 theoretical emission value, the current NH3 actual emission value represents the actual NH3 emission value of the engine under the current operating condition, and the current NH3 theoretical emission value is the theoretical emission value of the engine under the current operating condition; a correction unit is used to determine the current NOx actual emission value based on the current NOx mass measurement value and the measurement deviation value, and the NOx actual emission value is the difference between the NOx mass measurement value and the measurement deviation value.

[0012] According to another aspect of the present application, a computer-readable storage medium is provided, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the methods for determining the NOx emission value of the engine.

[0013] According to another aspect of the present application, an electronic device is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for determining the NOx emission value of an engine according to any one of the above methods.

[0014] Applying the technical solution of the present application, the method for determining the NOx emission value of the above-mentioned engine first obtains the current NOx mass measurement value, which is the measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification; secondly, obtains the measurement deviation value, which is the sum of the current NH3 actual emission value and the preset NOx mass average value, and the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off conditions within a first preset time period before the current moment, and the preset NOx mass measurement value corresponds one-to-one to the fuel cut-off condition, and the current NH3 actual emission value is obtained by correcting the current NH3 theoretical emission value, and the current NH3 actual emission value represents the actual NH3 emission value of the engine under the current operating conditions, and the current NH3 theoretical emission value is the theoretical emission value of the engine under the current operating conditions; finally, the current NOx actual emission value is determined based on the current NOx mass measurement value and the measurement deviation value, and the NOx actual emission value is the difference between the NOx mass measurement value and the measurement deviation value. This method accurately calculates the actual NH3 emission value under the current operating conditions, improves the control accuracy of the NOx closed loop, thereby ensuring performance indicators such as engine emissions and economy, and solves the problem of inaccurate calculation of NOx actual value caused by NH3 cross-sensitivity and aging drift of NOx sensor signals in the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0016] Figure 1 A hardware structure block diagram of a mobile terminal for executing a method for determining an engine NOx emission value provided in an embodiment of the present application is shown;

[0017] Figure 2 A flow chart of a method for determining an engine NOx emission value according to an embodiment of the present application is shown;

[0018] Figure 3 A flow chart illustrating another method for determining an engine NOx emission value according to an embodiment of the present application is shown;

[0019] Figure 4 A flow chart of another method for determining an engine NOx emission value provided in accordance with an embodiment of the present application is shown;

[0020] Figure 5 A flow chart of another method for determining an engine NOx emission value provided in accordance with an embodiment of the present application is shown;

[0021] Figure 6 A structural block diagram of a device for determining an engine NOx emission value provided in accordance with an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] For ease of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0026] MAP: spectrum map, input X, Y, output the corresponding value Z;

[0027] CURVE: One-dimensional array, input X, output the corresponding value Y;

[0028] EEP: Short for EEPROM, an electrically erasable programmable read-only memory, is a storage chip that does not lose data after power failure.

[0029] Original emissions: the original emissions of the engine, that is, the original emissions without purification by post-treatment devices;

[0030] Tail exhaust: the final emission of the engine, that is, the final emission after post-processing and purification.

[0031] As introduced in the background technology, the prior art directly uses the NOx value collected by the NOx sensor and the target NOx value to perform closed-loop correction of the air-fuel ratio. Since the cross-sensitivity characteristics of NH3 and the aging and drift problems of the NOx sensor are not taken into consideration, the NOx signal will be unreliable, further affecting the accuracy of the NOx closed-loop control, which is not conducive to the engine's emissions and economy. In order to solve the problem of inaccurate calculation of the actual NOx value due to the cross-sensitivity of NH3 and the aging and drift of the NOx sensor signal in the prior art, the embodiments of the present application provide a method for determining the NOx emission value of an engine, a device for determining the NOx emission value of an engine, a readable storage medium and an electronic device.

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a 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 determining an engine NOx emission value according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown) a processor 102 (the processor 102 may include but is not limited to a microprocessor MCU or a programmable logic device FPGA and other processing devices) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It will be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components than shown, or with Figure 1 Different configurations shown.

[0034] The memory 104 can be used to store computer programs, such as software programs and modules of application software, such as the computer program corresponding to the device information display method in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, implementing the above-mentioned method. The memory 104 may include a high-speed random access memory and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a 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 above-mentioned 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 above-mentioned network may include a wireless network provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, abbreviated as 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.

[0035] In this embodiment, a method for determining the NOx emission value of an engine running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of 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 can be executed in an order different from that shown here.

[0036] Figure 2 FIG. 1 is a flow chart of a method for determining an engine NOx emission value according to an embodiment of the present application. Figure 2 As shown, the method includes the following steps:

[0037] Step S201, obtaining a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification;

[0038] Specifically, the National VI natural gas engine with the equivalent combustion technology route has almost no NH3 emissions in the original exhaust, but after the chemical reactions of various emissions inside the catalyst, there are large amounts of NH3 emissions in the tail exhaust. The factors affecting the amount of NH3 emissions inside the catalyst are mainly: ① Engine operating conditions, the emission content in the exhaust gas is different under different engine operating conditions; ② Engine exhaust temperature, the exhaust temperature affects the rate of each chemical reaction in the catalyst; ③ Air-fuel ratio, the air-fuel ratio affects the combustion state of the engine, thereby affecting the content of various emissions in the exhaust gas; ④ Catalyst state, the aging state of the catalyst affects the conversion efficiency of the catalyst, thereby affecting the chemical reaction inside the catalyst.

[0039] Before entering step S202, Figure 3 As shown, the above method also includes the following steps:

[0040] Step S301, obtaining the current speed and current intake pressure of the engine under the current working condition;

[0041] Step S302: obtaining a first mapping relationship, wherein the first mapping relationship is used to represent a mapping relationship between the engine speed, the engine intake pressure, and the theoretical NH3 emission value;

[0042] Step S303, based on the current speed of the engine, the current intake pressure of the engine and the first mapping relationship, determine the theoretical NH3 emission value corresponding to the current speed of the engine and the current intake pressure of the engine as the current theoretical NH3 emission value.

[0043] Specifically, the first mapping relationship can be a first MAP table, which is a preset basic MAP for NH3 emissions. The values ​​in the MAP are written into the ECU after being measured on a standard calibration bench based on a standard prototype (calibration engine) and an NH3 signal sensor installed during calibration. By correcting the current theoretical NH3 emission value, the actual NH3 emission value can be obtained, and the current actual NOx emission value can be accurately obtained.

[0044] In addition, before entering step S202, if Figure 4 As shown, the above method also includes the following steps:

[0045] Step S401, obtaining the current air-fuel ratio of the engine and the current exhaust temperature of the engine;

[0046] Step S402: obtaining a second mapping relationship, wherein the second mapping relationship is used to represent a mapping relationship between the air-fuel ratio of the engine, the exhaust temperature of the engine, and the NH3 emission correction value;

[0047] Step S403, based on the current air-fuel ratio of the above-mentioned engine, the current exhaust temperature of the above-mentioned engine and the above-mentioned second mapping relationship, determine the above-mentioned NH3 emission correction value corresponding to the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine as the current NH3 emission correction value, wherein the above-mentioned current NH3 emission correction value is used to correct the current NH3 theoretical emission value.

[0048] Specifically, the second mapping relationship can be a second MAP table, which is also a correction value confirmed on a standard calibration bench based on the impact of different exhaust temperatures and air-fuel ratios on NH3 emissions, and then written into the ECU; wherein the above-mentioned current NH3 emission correction value is used to correct the current NH3 theoretical emission value. The specific correction method can be any one of addition, subtraction, multiplication and division, which can be selected and applied according to actual conditions. No specific limitation is made here. The above steps can obtain an accurate current NH3 emission correction value, and then obtain the current actual NOx emission value.

[0049] In one embodiment, before entering step S202, the above method may further include the following steps:

[0050] Step S501, obtaining a current aging factor of a reaction catalyst, wherein the reaction catalyst is used to catalyze various types of emissions in the raw emissions of the engine to perform chemical reactions, wherein the raw emissions are engine emissions that have not undergone post-processing purification;

[0051] Step S502: obtaining a first preset array, wherein the first preset array is used to represent a mapping relationship between an aging factor of the reaction catalyst and an NH3 correction factor;

[0052] Step S503, determining the NH3 correction factor corresponding to the current aging factor of the reaction catalyst as the current NH3 correction factor according to the current aging factor of the reaction catalyst and the first preset array;

[0053] Step S504, using the current NH3 emission correction value and the above-mentioned current NH3 correction factor to correct the above-mentioned current NH3 theoretical emission value to obtain the above-mentioned NH3 actual emission value. The above-mentioned NH3 actual emission value is the product of the target value and the above-mentioned current NH3 correction factor, and the above-mentioned target value is the sum of the above-mentioned current NH3 theoretical emission value and the above-mentioned current NH3 emission correction value.

[0054] Specifically, the first preset array can be the first CURVE array. The aging factor calibration method also uses a standard calibration bench to determine the impact of varying exhaust temperatures and air-fuel ratios on NH3 emissions. Correction values ​​are then written into the ECU. It should be noted that the above steps only disclose one correction method. Depending on the actual situation, any calculation using the current NH3 emission correction value and the current NH3 correction factor can be used to correct the current theoretical NH3 emissions value. Examples are not provided here. After correction, accurate actual NH3 emissions values ​​can be obtained, and thus, the current actual NOx emissions value.

[0055] In another solution, one of the first preset time periods includes a plurality of the fuel cut-off conditions. Before entering step S202, the method further includes:

[0056] Step S601, obtaining the exhaust gas discharge time under each of the fuel cut-off operating conditions within the first preset time period, wherein the exhaust gas discharge time is the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off operating condition;

[0057] The above step S601 specifically includes the following steps:

[0058] Step S6011, obtaining the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period;

[0059] Step S6012: obtaining a second preset array, wherein the second preset array is used to represent a mapping relationship between the engine speed and the exhaust gas discharge time under each of the fuel cut-off conditions within the first preset time period;

[0060] Step S6013, based on the real-time speed of the engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned second preset array, determine the multiple exhaust gas discharge times corresponding to the real-time speed of the engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period as the above-mentioned exhaust gas discharge times under each of the above-mentioned fuel cut-off conditions.

[0061] Specifically, the second preset array can be a second CURVE array, with the end time of the first preset time period being the current time. In practical applications, it can also be calibrated to each fuel cut-off condition within a predetermined range, or the number of fuel cut-off conditions can be calibrated. For example, two or three collected values ​​can be used for calculation and judgment. Because the engine does not perform injection and combustion after entering the fuel cut-off condition, in principle, no emissions are present in the exhaust gas. Sensor aging and signal drift are corrected based on the values ​​collected by the NOx sensor during the fuel cut-off condition. The exhaust gas discharge time is obtained by querying the preset CURVE based on the engine speed. The exhaust gas discharge time varies at different speeds. The purpose of this exhaust gas discharge time is to prevent the accuracy of NOx sensor signal acquisition from being affected by incomplete exhaust gas discharge due to delayed gas flow after the engine enters the fuel cut-off condition.

[0062] Step S602, after the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has elapsed, obtaining the preset NOx mass measurement value under each of the fuel cut-off conditions within the first preset time period, to obtain a plurality of the preset NOx mass measurement values;

[0063] Step S603, calculating an average value of the plurality of the preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value;

[0064] Step S604 : determining the preset NOx mass average value according to the magnitude relationship between the plurality of the preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

[0065] Specifically, the above steps are to ensure that the deviation of the value collected each time is very small during multiple collection and calculation processes, which represents the stability of the collected values.

[0066] The above step S604 specifically includes the following steps:

[0067] Step S6041, obtaining a plurality of difference values, wherein one difference value is a difference between the preset NOx mass measurement value and the first initial NOx mass average value;

[0068] Step S6042: If the plurality of differences are all less than or equal to a preset difference, determining the first initial NOx mass average value as the preset NOx mass average value;

[0069] Step S6043: When at least one of the above-mentioned differences is greater than the above-mentioned preset difference, determine that the second initial NOx mass average value obtained in the second preset time period is the above-mentioned preset NOx mass average value in the above-mentioned first preset time period, and the above-mentioned second preset time period is before the above-mentioned first preset time period.

[0070] Specifically, in the case of a numerical value with excessive deviation, continuing to use the NOx mass average value used in the previous cycle as the preset NOx mass average value this time can improve the stability of the numerical value.

[0071] Step S202: Obtaining a measurement deviation value, where the measurement deviation value is the sum of a current actual NH3 emission value and a preset NOx mass average value, where the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off operating conditions within a first preset time period before the current moment, and the preset NOx mass measurement values ​​correspond one-to-one to the fuel cut-off operating conditions. The current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value, and the current actual NH3 emission value represents the actual NH3 emission value of the engine under the current operating condition, while the current theoretical NH3 emission value represents the theoretical emission value of the engine under the current operating condition.

[0072] Specifically, the actual value measured by the NOx sensor is not only interfered by the current actual NH3 emission value, but also by the NOx existing under the fuel cut-off condition. Therefore, simply eliminating the interference of the current actual NH3 emission value cannot obtain the accurate current actual NOx emission value. The interference of NOx existing under the fuel cut-off condition must also be eliminated.

[0073] Step S203 , determining a current actual NOx emission value according to the current NOx mass measurement value and the measurement deviation value, where the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value.

[0074] Specifically, the current actual NOx emission value can be accurately obtained by excluding the current actual NH3 emission value and the interference of NOx existing under the fuel cut-off condition from the value measured by the actual NOx sensor.

[0075] The above-mentioned method for determining the NOx emission value of the engine of the present application first obtains the current NOx mass measurement value, which is the measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-treatment purification; secondly, a measurement deviation value is obtained, which is the sum of the current NH3 actual emission value and the preset NOx mass average value, and the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off conditions within a first preset time period before the current moment, and the preset NOx mass measurement value corresponds one-to-one to the fuel cut-off condition, and the current NH3 actual emission value is obtained by correcting the current NH3 theoretical emission value, and the current NH3 actual emission value represents the actual NH3 emission value of the engine under the current operating conditions, and the current NH3 theoretical emission value is the theoretical emission value of the engine under the current operating conditions; finally, the current NOx actual emission value is determined based on the current NOx mass measurement value and the measurement deviation value, and the NOx actual emission value is the difference between the NOx mass measurement value and the measurement deviation value. This method accurately calculates the actual NH3 emission value under the current operating conditions, improves the control accuracy of the NOx closed loop, thereby ensuring performance indicators such as engine emissions and economy, and solves the problem of inaccurate calculation of NOx actual value caused by NH3 cross-sensitivity and aging drift of NOx sensor signals in the existing technology.

[0076] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the method for determining the NOx emission value of the engine of the present application will be described in detail below with reference to specific embodiments.

[0077] This embodiment relates to a specific method for determining the NOx emission value of an engine, such as Figure 5 As shown, the following steps are included:

[0078] Step 1: When the ECU is powered on, it reads parameters such as the catalyst aging factor and the NOx signal value under fuel cut-off condition stored in the previous driving cycle from the EEP;

[0079] Step 2: Obtain parameters such as engine speed, actual air-fuel ratio, NOx signal value collected by the NOx sensor, intake pressure, and engine exhaust temperature;

[0080] Step 3: Check the preset basic MAP1 based on the engine speed and intake pressure to obtain the NH3 emission basic value A in the tail exhaust under the current working condition;

[0081] Step 4: Check the preset correction MAP2 based on the actual values ​​of the engine exhaust temperature and air-fuel ratio to obtain the NH3 emission correction value B in the tail exhaust under the current working condition;

[0082] Step 5: According to the catalyst aging factor, the preset CURVE1 is checked to obtain the correction factor C of the NH3 emission value in the tail exhaust;

[0083] Step 6: Calculate the final value of NH3 emissions from the engine exhaust under the current operating conditions: D = (A + B) × C;

[0084] Step 7: Determine whether the engine has entered the fuel cut-off condition;

[0085] If the engine enters the fuel cut-off condition, execute step 9; if the engine does not enter the fuel cut-off condition, execute step 8;

[0086] Step 8: Use the E value read from the EEP when the ECU is powered on as the NOx signal value under fuel cut-off conditions. Calculate a new E value when the fuel cut-off condition is met in the current driving cycle.

[0087] Step 9: After a delay of time T, record the tail NOx sensor signal value E1 at this time, which represents the actual NOx value collected by the sensor during the fuel cut-off condition;

[0088] Step 10: After accumulating statistics N times according to steps 7 and 9, calculate the difference between the NOx signal value E1...N recorded each time and the average value E of N times;

[0089] Step 11: Determine whether each difference is within a preset range;

[0090] If all the differences are within the preset range, execute step 13; if one difference is not within the preset range, execute step 12;

[0091] Step 12: The NOx sensor signal value recorded during the fuel cut-off condition is unreliable. This driving cycle uses the E read from the EEP when the ECU is powered on as the NOx signal value during the fuel cut-off condition.

[0092] Step 13: The NOx sensor signal value recorded during the fuel cut-off condition is reliable. The average value E is used as the NOx sensor signal value during the fuel cut-off condition and stored in the EEP when the ECU is powered off. The E confirmed during this driving cycle is used to update the E stored during the previous driving cycle.

[0093] Step 14: Calculate the final value of NOx emissions in the engine tail exhaust under the current operating conditions: F = NOx signal value collected by the NOx sensor - DE;

[0094] Step 15: Use the final calculated NOx signal value and the NOx signal value set under the working condition to perform closed-loop control, output the correction parameters of the air-fuel ratio, and finally achieve NOx emissions that meet emission requirements.

[0095] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0096] The embodiments of the present application also provide a device for determining the NOx emission value of an engine. It should be noted that the device for determining the NOx emission value of an engine according to the embodiments of the present application can be used to execute the method for determining the NOx emission value of an engine provided by the embodiments of the present application. The device is used to implement the above-mentioned embodiments and preferred embodiments, and the details that have been described will not be repeated here. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.

[0097] The following is an introduction to the device for determining the NOx emission value of an engine provided in an embodiment of the present application.

[0098] Figure 6 Schematic diagram of a device for determining an engine NOx emission value according to an embodiment of the present application. Figure 6 As shown, the device includes a first acquisition unit 10, a second acquisition unit 20 and a correction unit 30, the first acquisition unit 10 is used to obtain the current NOx mass measurement value, the current NOx mass measurement value is the measurement value of the NOx mass in the final emission of the engine under the current working condition, and the final emission is the engine emission after post-processing purification; the second acquisition unit 20 is used to obtain a measurement deviation value, the measurement deviation value is the sum of the current NH3 actual emission value and the preset NOx mass average value, and the preset NOx mass average value is the multiple preset values ​​corresponding to multiple fuel cut-off conditions in a first preset time period before the current moment. The average value of the NOx mass measurement value, the above-mentioned preset NOx mass measurement value corresponds one-to-one with the above-mentioned fuel cut-off operating condition, the above-mentioned current NH3 actual emission value is obtained by correcting the current NH3 theoretical emission value, the above-mentioned current NH3 actual emission value represents the actual NH3 emission value of the above-mentioned engine under the current operating condition, and the above-mentioned current NH3 theoretical emission value is the theoretical emission value of the above-mentioned engine under the current operating condition; the correction unit 30 is used to determine the current NOx actual emission value based on the above-mentioned current NOx mass measurement value and the above-mentioned measurement deviation value, and the above-mentioned NOx actual emission value is the difference between the above-mentioned NOx mass measurement value and the above-mentioned measurement deviation value.

[0099] The above-mentioned engine NOx emission value determination device of the present application, the first acquisition unit is used to obtain the current NOx mass measurement value, the current NOx mass measurement value is the measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-treatment purification; the second acquisition unit is used to obtain the measurement deviation value, the measurement deviation value is the sum of the current NH3 actual emission value and the preset NOx mass average value, the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off conditions within a first preset time period before the current moment, the preset NOx mass measurement value corresponds one-to-one to the fuel cut-off condition, the current NH3 actual emission value is obtained by correcting the current NH3 theoretical emission value, the current NH3 actual emission value represents the actual NH3 emission value of the engine under the current operating conditions, and the current NH3 theoretical emission value is the theoretical emission value of the engine under the current operating conditions; the correction unit is used to determine the current NOx actual emission value based on the current NOx mass measurement value and the measurement deviation value, the NOx actual emission value is the difference between the NOx mass measurement value and the measurement deviation value. The device accurately calculates the actual NH3 emission value under the current operating conditions, improving the control accuracy of the NOx closed loop, thereby ensuring performance indicators such as engine emissions and economy, and solving the problem of inaccurate calculation of NOx actual values ​​caused by NH3 cross-sensitivity and aging drift of NOx sensor signals in the existing technology.

[0100] In an optional solution, the device further includes a third acquisition unit, a fourth acquisition unit, and a first determination unit. The third acquisition unit is used to acquire the current speed and current intake pressure of the engine under the current operating condition before acquiring the measurement deviation value. The fourth acquisition unit is used to acquire a first mapping relationship, wherein the first mapping relationship is used to represent the mapping relationship between the speed of the engine, the intake pressure of the engine, and the theoretical NH3 emission value. The fourth acquisition unit is used to determine, based on the current speed of the engine, the current intake pressure of the engine, and the first mapping relationship, the theoretical NH3 emission value corresponding to the current speed of the engine and the current intake pressure of the engine as the current theoretical NH3 emission value. Correcting the current theoretical NH3 emission value can obtain the actual NH3 emission value, and thus accurately obtain the current actual NOx emission value.

[0101] Exemplarily, the apparatus further includes a fifth acquisition unit, a sixth acquisition unit, and a second determination unit. The fifth acquisition unit is configured to acquire the current air-fuel ratio of the engine and the current exhaust temperature of the engine before acquiring the measurement deviation value. The sixth acquisition unit is configured to acquire a second mapping relationship, wherein the second mapping relationship is configured to represent a mapping relationship between the air-fuel ratio of the engine, the exhaust temperature of the engine, and the NH3 emission correction value. The second determination unit is configured to determine, based on the current air-fuel ratio of the engine, the current exhaust temperature of the engine, and the second mapping relationship, the NH3 emission correction value corresponding to the current air-fuel ratio of the engine and the current exhaust temperature of the engine as a current NH3 emission correction value. The current NH3 emission correction value is used to correct the current theoretical NH3 emission value. Thus, an accurate current NH3 emission correction value can be obtained, thereby obtaining the current actual NOx emission value.

[0102] In an optional embodiment, the device further includes a seventh acquisition unit, an eighth acquisition unit, a third determination unit, and a correction subunit, wherein the seventh acquisition unit is configured to acquire a current aging factor of a reaction catalyst before acquiring the measurement deviation value, the reaction catalyst being configured to catalyze chemical reactions of various types of emissions in the original emissions of the engine, the original emissions being engine emissions that have not undergone post-processing purification; the eighth acquisition unit is configured to acquire a first preset array, the first preset array being configured to represent a mapping relationship between the aging factor of the reaction catalyst and the NH3 correction factor; the third determination unit is configured to determine, based on the current aging factor of the reaction catalyst and the first preset array, the NH3 correction factor corresponding to the current aging factor of the reaction catalyst as the current NH3 correction factor; and the correction subunit is configured to correct the current theoretical NH3 emission value using the current NH3 emission correction value and the current NH3 correction factor to obtain the actual NH3 emission value, the actual NH3 emission value being the product of a target value and the current NH3 correction factor, and the target value being the sum of the current theoretical NH3 emission value and the current NH3 emission correction value. After correction, the accurate actual NH3 emission value can be obtained, and then the current actual NOx emission value can be obtained.

[0103] As an optional solution, the first preset time period includes multiple fuel cut-off conditions. The apparatus further includes a first acquisition module, a second acquisition module, a calculation module, and a determination module. The first acquisition module is configured to acquire the exhaust gas discharge time under each fuel cut-off condition within the first preset time period before acquiring the measurement deviation value. The exhaust gas discharge time is the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off condition. The second acquisition module is configured to acquire the preset NOx mass measurement value under each fuel cut-off condition within the first preset time period after the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has elapsed, thereby obtaining multiple preset NOx mass measurement values. The calculation module is configured to calculate an average of the multiple preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value. The determination module is configured to determine the preset NOx mass average value based on the relationship between the multiple preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value. This ensures that the deviation of each acquired value is very small during multiple acquisitions and calculations, indicating the stability of the acquired values.

[0104] Exemplarily, the determination module includes an acquisition submodule, a first determination submodule, and a second determination submodule. The acquisition module is configured to acquire multiple differences, wherein one difference is the difference between a preset NOx mass measurement value and the first initial NOx mass average value. The first determination submodule is configured to determine the first initial NOx mass average value as the preset NOx mass average value when multiple differences are less than or equal to the preset difference value. The second determination submodule is configured to determine a second initial NOx mass average value acquired within a second preset time period as the preset NOx mass average value within the first preset time period when at least one difference value is greater than the preset difference value. The second preset time period is prior to the first preset time period. In the event of excessively deviated values, the NOx mass average value used in the previous cycle is continued to be used as the preset NOx mass average value for this current cycle, thereby improving the stability of the values.

[0105] As an optional embodiment, the first acquisition module includes a first acquisition submodule, a second acquisition submodule, and a third determination submodule. The first acquisition submodule is configured to acquire the real-time engine speed under each of the fuel cut-off conditions within the first preset time period; the second acquisition submodule is configured to acquire a second preset array representing a mapping relationship between the engine speed under each of the fuel cut-off conditions within the first preset time period and the exhaust gas discharge time; and the third determination submodule is configured to determine, based on the real-time engine speed under each of the fuel cut-off conditions within the first preset time period and the second preset array, a plurality of exhaust gas discharge times corresponding to the real-time engine speed under each of the fuel cut-off conditions within the first preset time period as the exhaust gas discharge time under each of the fuel cut-off conditions. This prevents the situation in which some exhaust gas is not fully discharged due to gas flow delay after the engine enters the fuel cut-off condition, thereby affecting the accuracy of NOx sensor signal acquisition.

[0106] The apparatus for determining engine NOx emissions includes a processor and a memory. The first acquisition unit and other components are stored as program units in the memory, and the processor executes the program units stored in the memory to implement corresponding functions. The modules are all located in the same processor; alternatively, the modules may be located in different processors in any combination.

[0107] The processor includes a core, which retrieves the corresponding program unit from memory. One or more cores can be configured, and adjusting core parameters can address the existing issue of inaccurate NOx actual value calculations due to NH3 cross-sensitivity and NOx sensor signal aging and drift.

[0108] The memory may include non-permanent memory in a computer-readable medium, 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.

[0109] An embodiment of the present invention provides a computer-readable storage medium, which includes a stored program. When the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for determining the NOx emission value of the engine.

[0110] Specifically, the method for determining the engine NOx emission value includes:

[0111] Step S201, obtaining a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification;

[0112] Specifically, the National VI natural gas engine with the equivalent combustion technology route has almost no NH3 emissions in the original exhaust, but after the chemical reactions of various emissions inside the catalyst, there are large amounts of NH3 emissions in the tail exhaust. The factors affecting the amount of NH3 emissions inside the catalyst are mainly: ① Engine operating conditions, the emission content in the exhaust gas is different under different engine operating conditions; ② Engine exhaust temperature, the exhaust temperature affects the rate of each chemical reaction in the catalyst; ③ Air-fuel ratio, the air-fuel ratio affects the combustion state of the engine, thereby affecting the content of various emissions in the exhaust gas; ④ Catalyst state, the aging state of the catalyst affects the conversion efficiency of the catalyst, thereby affecting the chemical reaction inside the catalyst.

[0113] Step S202: Obtaining a measurement deviation value, where the measurement deviation value is the sum of a current actual NH3 emission value and a preset NOx mass average value, where the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off operating conditions within a first preset time period before the current moment, and the preset NOx mass measurement values ​​correspond one-to-one to the fuel cut-off operating conditions. The current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value, and the current actual NH3 emission value represents the actual NH3 emission value of the engine under the current operating condition, while the current theoretical NH3 emission value represents the theoretical emission value of the engine under the current operating condition.

[0114] Specifically, the actual value measured by the NOx sensor is not only interfered by the current actual NH3 emission value, but also by the NOx existing under the fuel cut-off condition. Therefore, simply eliminating the interference of the current actual NH3 emission value cannot obtain the accurate current actual NOx emission value. The interference of NOx existing under the fuel cut-off condition must also be eliminated.

[0115] Step S203 , determining a current actual NOx emission value according to the current NOx mass measurement value and the measurement deviation value, where the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value.

[0116] Specifically, the current actual NOx emission value can be accurately obtained by excluding the current actual NH3 emission value and the interference of NOx existing under the fuel cut-off condition from the value measured by the actual NOx sensor.

[0117] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current speed and current intake pressure of the above-mentioned engine under the current working conditions; obtaining a first mapping relationship, the above-mentioned first mapping relationship is used to represent the mapping relationship between the speed of the above-mentioned engine, the intake pressure of the above-mentioned engine and the NH3 theoretical emission value; according to the current speed of the above-mentioned engine, the current intake pressure of the above-mentioned engine and the above-mentioned first mapping relationship, determining that the above-mentioned NH3 theoretical emission value corresponding to the current speed of the above-mentioned engine and the current intake pressure of the above-mentioned engine is the above-mentioned current NH3 theoretical emission value.

[0118] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine; obtaining a second mapping relationship, the above-mentioned second mapping relationship is used to represent the mapping relationship between the air-fuel ratio of the above-mentioned engine, the exhaust temperature of the above-mentioned engine and the NH3 emission correction value; according to the current air-fuel ratio of the above-mentioned engine, the current exhaust temperature of the above-mentioned engine and the above-mentioned second mapping relationship, determining the above-mentioned NH3 emission correction value corresponding to the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine as the current NH3 emission correction value, wherein the above-mentioned current NH3 emission correction value is used to correct the current NH3 theoretical emission value.

[0119] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining a current aging factor of the reaction catalyst, the above-mentioned reaction catalyst is used to catalyze chemical reactions of various types of emissions in the original emissions of the above-mentioned engine, and the above-mentioned original emissions are engine emissions that have not been post-processed and purified; obtaining a first preset array, the above-mentioned first preset array is used to represent the mapping relationship between the aging factor of the above-mentioned reaction catalyst and the NH3 correction factor; according to the current aging factor of the above-mentioned reaction catalyst and the above-mentioned first preset array, determining the above-mentioned NH3 correction factor corresponding to the current aging factor of the above-mentioned reaction catalyst as the current NH3 correction factor; using the current NH3 emission correction value and the above-mentioned current NH3 correction factor to correct the above-mentioned current NH3 theoretical emission value to obtain the above-mentioned NH3 actual emission value, the above-mentioned NH3 actual emission value is the product of the target value and the above-mentioned current NH3 correction factor, and the above-mentioned target value is the sum of the above-mentioned current NH3 theoretical emission value and the above-mentioned current NH3 emission correction value.

[0120] Optionally, the first preset time period includes multiple fuel cut-off conditions. Before obtaining the measurement deviation value, the method further includes: obtaining the exhaust gas discharge time under each fuel cut-off condition within the first preset time period, the exhaust gas discharge time being the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off condition; obtaining the preset NOx mass measurement value under each fuel cut-off condition within the first preset time period after the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has passed, and obtaining multiple preset NOx mass measurement values; calculating the average value of the multiple preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value; and determining the preset NOx mass average value based on the relationship between the multiple preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

[0121] Optionally, the preset NOx mass average value is determined based on the size relationship between the multiple preset NOx mass measurement values ​​and the first initial NOx mass average value within the first preset time period, including: obtaining multiple difference values, one difference value being the difference between one preset NOx mass measurement value and the first initial NOx mass average value; when the multiple difference values ​​are all less than or equal to the preset difference value, determining the first initial NOx mass average value as the preset NOx mass average value; when at least one difference value is greater than the preset difference value, determining the second initial NOx mass average value obtained within the second preset time period as the preset NOx mass average value within the first preset time period, and the second preset time period is before the first preset time period.

[0122] Optionally, obtaining the exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period includes: obtaining the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period; obtaining a second preset array, the above-mentioned second preset array being used to represent the mapping relationship between the speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned exhaust gas discharge time; based on the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned second preset array, determining a plurality of the above-mentioned exhaust gas discharge times corresponding to the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period as the above-mentioned exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions.

[0123] An embodiment of the present invention provides a processor, which is used to run a program, wherein the method for determining the NOx emission value of the engine is executed when the program is run.

[0124] Specifically, the method for determining the engine NOx emission value includes:

[0125] Step S201, obtaining a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification;

[0126] Specifically, the National VI natural gas engine with the equivalent combustion technology route has almost no NH3 emissions in the original exhaust, but after the chemical reactions of various emissions inside the catalyst, there are large amounts of NH3 emissions in the tail exhaust. The factors affecting the amount of NH3 emissions inside the catalyst are mainly: ① Engine operating conditions, the emission content in the exhaust gas is different under different engine operating conditions; ② Engine exhaust temperature, the exhaust temperature affects the rate of each chemical reaction in the catalyst; ③ Air-fuel ratio, the air-fuel ratio affects the combustion state of the engine, thereby affecting the content of various emissions in the exhaust gas; ④ Catalyst state, the aging state of the catalyst affects the conversion efficiency of the catalyst, thereby affecting the chemical reaction inside the catalyst.

[0127] Step S202: Obtaining a measurement deviation value, where the measurement deviation value is the sum of a current actual NH3 emission value and a preset NOx mass average value, where the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off operating conditions within a first preset time period before the current moment, and the preset NOx mass measurement values ​​correspond one-to-one to the fuel cut-off operating conditions. The current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value, and the current actual NH3 emission value represents the actual NH3 emission value of the engine under the current operating condition, while the current theoretical NH3 emission value represents the theoretical emission value of the engine under the current operating condition.

[0128] Specifically, the actual value measured by the NOx sensor is not only interfered by the current actual NH3 emission value, but also by the NOx existing under the fuel cut-off condition. Therefore, simply eliminating the interference of the current actual NH3 emission value cannot obtain the accurate current actual NOx emission value. The interference of NOx existing under the fuel cut-off condition must also be eliminated.

[0129] Step S203 , determining a current actual NOx emission value according to the current NOx mass measurement value and the measurement deviation value, where the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value.

[0130] Specifically, the current actual NOx emission value can be accurately obtained by excluding the current actual NH3 emission value and the interference of NOx existing under the fuel cut-off condition from the value measured by the actual NOx sensor.

[0131] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current speed and current intake pressure of the above-mentioned engine under the current working conditions; obtaining a first mapping relationship, the above-mentioned first mapping relationship is used to represent the mapping relationship between the speed of the above-mentioned engine, the intake pressure of the above-mentioned engine and the NH3 theoretical emission value; according to the current speed of the above-mentioned engine, the current intake pressure of the above-mentioned engine and the above-mentioned first mapping relationship, determining that the above-mentioned NH3 theoretical emission value corresponding to the current speed of the above-mentioned engine and the current intake pressure of the above-mentioned engine is the above-mentioned current NH3 theoretical emission value.

[0132] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine; obtaining a second mapping relationship, the above-mentioned second mapping relationship is used to represent the mapping relationship between the air-fuel ratio of the above-mentioned engine, the exhaust temperature of the above-mentioned engine and the NH3 emission correction value; according to the current air-fuel ratio of the above-mentioned engine, the current exhaust temperature of the above-mentioned engine and the above-mentioned second mapping relationship, determining the above-mentioned NH3 emission correction value corresponding to the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine as the current NH3 emission correction value, wherein the above-mentioned current NH3 emission correction value is used to correct the current NH3 theoretical emission value.

[0133] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining a current aging factor of the reaction catalyst, the above-mentioned reaction catalyst is used to catalyze chemical reactions of various types of emissions in the original emissions of the above-mentioned engine, and the above-mentioned original emissions are engine emissions that have not been post-processed and purified; obtaining a first preset array, the above-mentioned first preset array is used to represent the mapping relationship between the aging factor of the above-mentioned reaction catalyst and the NH3 correction factor; according to the current aging factor of the above-mentioned reaction catalyst and the above-mentioned first preset array, determining the above-mentioned NH3 correction factor corresponding to the current aging factor of the above-mentioned reaction catalyst as the current NH3 correction factor; using the current NH3 emission correction value and the above-mentioned current NH3 correction factor to correct the above-mentioned current NH3 theoretical emission value to obtain the above-mentioned NH3 actual emission value, the above-mentioned NH3 actual emission value is the product of the target value and the above-mentioned current NH3 correction factor, and the above-mentioned target value is the sum of the above-mentioned current NH3 theoretical emission value and the above-mentioned current NH3 emission correction value.

[0134] Optionally, the first preset time period includes multiple fuel cut-off conditions. Before obtaining the measurement deviation value, the method further includes: obtaining the exhaust gas discharge time under each fuel cut-off condition within the first preset time period, the exhaust gas discharge time being the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off condition; obtaining the preset NOx mass measurement value under each fuel cut-off condition within the first preset time period after the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has passed, and obtaining multiple preset NOx mass measurement values; calculating the average value of the multiple preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value; and determining the preset NOx mass average value based on the relationship between the multiple preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

[0135] Optionally, the preset NOx mass average value is determined based on the size relationship between the multiple preset NOx mass measurement values ​​and the first initial NOx mass average value within the first preset time period, including: obtaining multiple difference values, one difference value being the difference between one preset NOx mass measurement value and the first initial NOx mass average value; when the multiple difference values ​​are all less than or equal to the preset difference value, determining the first initial NOx mass average value as the preset NOx mass average value; when at least one difference value is greater than the preset difference value, determining the second initial NOx mass average value obtained within the second preset time period as the preset NOx mass average value within the first preset time period, and the second preset time period is before the first preset time period.

[0136] Optionally, obtaining the exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period includes: obtaining the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period; obtaining a second preset array, the above-mentioned second preset array being used to represent the mapping relationship between the speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned exhaust gas discharge time; based on the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned second preset array, determining a plurality of the above-mentioned exhaust gas discharge times corresponding to the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period as the above-mentioned exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions.

[0137] An embodiment of the present invention provides a device, comprising a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, at least the following steps are performed:

[0138] Step S201, obtaining a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification;

[0139] Step S202: Obtaining a measurement deviation value, where the measurement deviation value is the sum of a current actual NH3 emission value and a preset NOx mass average value, where the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off operating conditions within a first preset time period before the current moment, and the preset NOx mass measurement values ​​correspond one-to-one to the fuel cut-off operating conditions. The current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value, and the current actual NH3 emission value represents the actual NH3 emission value of the engine under the current operating condition, while the current theoretical NH3 emission value represents the theoretical emission value of the engine under the current operating condition.

[0140] Step S203 , determining a current actual NOx emission value according to the current NOx mass measurement value and the measurement deviation value, where the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value.

[0141] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0142] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current speed and current intake pressure of the above-mentioned engine under the current working conditions; obtaining a first mapping relationship, the above-mentioned first mapping relationship is used to represent the mapping relationship between the speed of the above-mentioned engine, the intake pressure of the above-mentioned engine and the NH3 theoretical emission value; according to the current speed of the above-mentioned engine, the current intake pressure of the above-mentioned engine and the above-mentioned first mapping relationship, determining that the above-mentioned NH3 theoretical emission value corresponding to the current speed of the above-mentioned engine and the current intake pressure of the above-mentioned engine is the above-mentioned current NH3 theoretical emission value.

[0143] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine; obtaining a second mapping relationship, the above-mentioned second mapping relationship is used to represent the mapping relationship between the air-fuel ratio of the above-mentioned engine, the exhaust temperature of the above-mentioned engine and the NH3 emission correction value; according to the current air-fuel ratio of the above-mentioned engine, the current exhaust temperature of the above-mentioned engine and the above-mentioned second mapping relationship, determining the above-mentioned NH3 emission correction value corresponding to the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine as the current NH3 emission correction value, wherein the above-mentioned current NH3 emission correction value is used to correct the current NH3 theoretical emission value.

[0144] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining a current aging factor of the reaction catalyst, the above-mentioned reaction catalyst is used to catalyze chemical reactions of various types of emissions in the original emissions of the above-mentioned engine, and the above-mentioned original emissions are engine emissions that have not been post-processed and purified; obtaining a first preset array, the above-mentioned first preset array is used to represent the mapping relationship between the aging factor of the above-mentioned reaction catalyst and the NH3 correction factor; according to the current aging factor of the above-mentioned reaction catalyst and the above-mentioned first preset array, determining the above-mentioned NH3 correction factor corresponding to the current aging factor of the above-mentioned reaction catalyst as the current NH3 correction factor; using the current NH3 emission correction value and the above-mentioned current NH3 correction factor to correct the above-mentioned current NH3 theoretical emission value to obtain the above-mentioned NH3 actual emission value, the above-mentioned NH3 actual emission value is the product of the target value and the above-mentioned current NH3 correction factor, and the above-mentioned target value is the sum of the above-mentioned current NH3 theoretical emission value and the above-mentioned current NH3 emission correction value.

[0145] Optionally, the first preset time period includes multiple fuel cut-off conditions. Before obtaining the measurement deviation value, the method further includes: obtaining the exhaust gas discharge time under each fuel cut-off condition within the first preset time period, the exhaust gas discharge time being the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off condition; obtaining the preset NOx mass measurement value under each fuel cut-off condition within the first preset time period after the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has passed, and obtaining multiple preset NOx mass measurement values; calculating the average value of the multiple preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value; and determining the preset NOx mass average value based on the relationship between the multiple preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

[0146] Optionally, the preset NOx mass average value is determined based on the size relationship between the multiple preset NOx mass measurement values ​​and the first initial NOx mass average value within the first preset time period, including: obtaining multiple difference values, one difference value being the difference between one preset NOx mass measurement value and the first initial NOx mass average value; when the multiple difference values ​​are all less than or equal to the preset difference value, determining the first initial NOx mass average value as the preset NOx mass average value; when at least one difference value is greater than the preset difference value, determining the second initial NOx mass average value obtained within the second preset time period as the preset NOx mass average value within the first preset time period, and the second preset time period is before the first preset time period.

[0147] Optionally, obtaining the exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period includes: obtaining the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period; obtaining a second preset array, the above-mentioned second preset array being used to represent the mapping relationship between the speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned exhaust gas discharge time; based on the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned second preset array, determining a plurality of the above-mentioned exhaust gas discharge times corresponding to the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period as the above-mentioned exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions.

[0148] The present application also provides a computer program product, which, when executed on a data processing device, is adapted to execute a program for initializing at least the following method steps:

[0149] Step S201, obtaining a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification;

[0150] Step S202: Obtaining a measurement deviation value, where the measurement deviation value is the sum of a current actual NH3 emission value and a preset NOx mass average value, where the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off operating conditions within a first preset time period before the current moment, and the preset NOx mass measurement values ​​correspond one-to-one to the fuel cut-off operating conditions. The current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value, and the current actual NH3 emission value represents the actual NH3 emission value of the engine under the current operating condition, while the current theoretical NH3 emission value represents the theoretical emission value of the engine under the current operating condition.

[0151] Step S203 , determining a current actual NOx emission value according to the current NOx mass measurement value and the measurement deviation value, where the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value.

[0152] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current speed and current intake pressure of the above-mentioned engine under the current working conditions; obtaining a first mapping relationship, the above-mentioned first mapping relationship is used to represent the mapping relationship between the speed of the above-mentioned engine, the intake pressure of the above-mentioned engine and the NH3 theoretical emission value; according to the current speed of the above-mentioned engine, the current intake pressure of the above-mentioned engine and the above-mentioned first mapping relationship, determining that the above-mentioned NH3 theoretical emission value corresponding to the current speed of the above-mentioned engine and the current intake pressure of the above-mentioned engine is the above-mentioned current NH3 theoretical emission value.

[0153] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine; obtaining a second mapping relationship, the above-mentioned second mapping relationship is used to represent the mapping relationship between the air-fuel ratio of the above-mentioned engine, the exhaust temperature of the above-mentioned engine and the NH3 emission correction value; according to the current air-fuel ratio of the above-mentioned engine, the current exhaust temperature of the above-mentioned engine and the above-mentioned second mapping relationship, determining the above-mentioned NH3 emission correction value corresponding to the current air-fuel ratio of the above-mentioned engine and the current exhaust temperature of the above-mentioned engine as the current NH3 emission correction value, wherein the above-mentioned current NH3 emission correction value is used to correct the current NH3 theoretical emission value.

[0154] Optionally, before obtaining the above-mentioned measurement deviation value, the above-mentioned method also includes: obtaining a current aging factor of the reaction catalyst, the above-mentioned reaction catalyst is used to catalyze chemical reactions of various types of emissions in the original emissions of the above-mentioned engine, and the above-mentioned original emissions are engine emissions that have not been post-processed and purified; obtaining a first preset array, the above-mentioned first preset array is used to represent the mapping relationship between the aging factor of the above-mentioned reaction catalyst and the NH3 correction factor; according to the current aging factor of the above-mentioned reaction catalyst and the above-mentioned first preset array, determining the above-mentioned NH3 correction factor corresponding to the current aging factor of the above-mentioned reaction catalyst as the current NH3 correction factor; using the current NH3 emission correction value and the above-mentioned current NH3 correction factor to correct the above-mentioned current NH3 theoretical emission value to obtain the above-mentioned NH3 actual emission value, the above-mentioned NH3 actual emission value is the product of the target value and the above-mentioned current NH3 correction factor, and the above-mentioned target value is the sum of the above-mentioned current NH3 theoretical emission value and the above-mentioned current NH3 emission correction value.

[0155] Optionally, the first preset time period includes multiple fuel cut-off conditions. Before obtaining the measurement deviation value, the method further includes: obtaining the exhaust gas discharge time under each fuel cut-off condition within the first preset time period, the exhaust gas discharge time being the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off condition; obtaining the preset NOx mass measurement value under each fuel cut-off condition within the first preset time period after the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has passed, and obtaining multiple preset NOx mass measurement values; calculating the average value of the multiple preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value; and determining the preset NOx mass average value based on the relationship between the multiple preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

[0156] Optionally, the preset NOx mass average value is determined based on the size relationship between the multiple preset NOx mass measurement values ​​and the first initial NOx mass average value within the first preset time period, including: obtaining multiple difference values, one difference value being the difference between one preset NOx mass measurement value and the first initial NOx mass average value; when the multiple difference values ​​are all less than or equal to the preset difference value, determining the first initial NOx mass average value as the preset NOx mass average value; when at least one difference value is greater than the preset difference value, determining the second initial NOx mass average value obtained within the second preset time period as the preset NOx mass average value within the first preset time period, and the second preset time period is before the first preset time period.

[0157] Optionally, obtaining the exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period includes: obtaining the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period; obtaining a second preset array, the above-mentioned second preset array being used to represent the mapping relationship between the speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned exhaust gas discharge time; based on the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period and the above-mentioned second preset array, determining a plurality of the above-mentioned exhaust gas discharge times corresponding to the real-time speed of the above-mentioned engine under each of the above-mentioned fuel cut-off conditions within the above-mentioned first preset time period as the above-mentioned exhaust gas discharge time under each of the above-mentioned fuel cut-off conditions.

[0158] Obviously, those skilled in the art will appreciate that the various modules or steps of the present invention described above can be implemented using a general-purpose computing device, can be centralized on a single computing device, or can be distributed across a network of multiple computing devices. They can be implemented using program code executable by the computing device, and thus, can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described herein can be performed in a different order than that shown, or 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.

[0159] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0160] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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 steps in the process. 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.

[0161] 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.

[0162] 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 A step that specifies a function in one or more boxes.

[0163] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0164] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0165] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules 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 technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0166] 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.

[0167] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0168] 1) The method for determining the NOx emission value of the above-mentioned engine of the present application first obtains the current NOx mass measurement value, which is the measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-processing purification; secondly, a measurement deviation value is obtained, which is the sum of the current actual NH3 emission value and the preset NOx mass average value, and the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off conditions within a first preset time period before the current moment, and the preset NOx mass measurement value corresponds to the fuel cut-off condition one-to-one, and the current actual NH3 emission value is obtained by correcting the current theoretical NH3 emission value, and the current actual NH3 emission value represents the actual NH3 emission value of the engine under the current operating conditions, and the current theoretical NH3 emission value is the theoretical emission value of the engine under the current operating conditions; finally, the current actual NOx emission value is determined based on the current NOx mass measurement value and the measurement deviation value, and the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value. This method accurately calculates the actual NH3 emission value under the current operating conditions, improves the control accuracy of the NOx closed loop, thereby ensuring performance indicators such as engine emissions and economy, and solves the problem of inaccurate calculation of NOx actual value caused by NH3 cross-sensitivity and aging drift of NOx sensor signals in the existing technology.

[0169] 2) The above-mentioned engine NOx emission value determination device of the present application, the first acquisition unit is used to obtain the current NOx mass measurement value, the current NOx mass measurement value is the measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, and the final emissions are the engine emissions after post-treatment purification; the second acquisition unit is used to obtain the measurement deviation value, the measurement deviation value is the sum of the current NH3 actual emission value and the preset NOx mass average value, the preset NOx mass average value is the average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off conditions within a first preset time period before the current moment, the preset NOx mass measurement value corresponds to the fuel cut-off condition one-to-one, the current NH3 actual emission value is obtained by correcting the current NH3 theoretical emission value, the current NH3 actual emission value represents the actual NH3 emission value of the engine under the current operating conditions, and the current NH3 theoretical emission value is the theoretical emission value of the engine under the current operating conditions; the correction unit is used to determine the current NOx actual emission value based on the current NOx mass measurement value and the measurement deviation value, the NOx actual emission value is the difference between the NOx mass measurement value and the measurement deviation value. The device accurately calculates the actual NH3 emission value under the current operating conditions, improving the control accuracy of the NOx closed loop, thereby ensuring performance indicators such as engine emissions and economy, and solving the problem of inaccurate calculation of NOx actual values ​​caused by NH3 cross-sensitivity and aging drift of NOx sensor signals in the existing technology.

[0170] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for determining an engine NOx emission value, characterized in that: include: Obtaining a current NOx mass measurement value, where the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating conditions, where the final emissions are engine emissions after post-processing purification; Obtaining a measurement deviation value, where the measurement deviation value is the sum of a current actual NH3 emission value and a preset NOx mass average value, where the preset NOx mass average value is an average value of multiple preset NOx mass measurement values ​​corresponding to multiple fuel cut-off operating conditions within a first preset time period before a current moment, where the preset NOx mass measurement values ​​correspond one-to-one to the fuel cut-off operating conditions, the current actual NH3 emission value is obtained by correcting a current theoretical NH3 emission value, and the current actual NH3 emission value represents an actual NH3 emission value of the engine under the current operating condition, and the current theoretical NH3 emission value represents a theoretical emission value of the engine under the current operating condition; A current actual NOx emission value is determined according to the current NOx mass measurement value and the measurement deviation value, where the actual NOx emission value is the difference between the NOx mass measurement value and the measurement deviation value.

2. The determination method according to claim 1, characterized in that Before obtaining the measurement deviation value, the method further includes: Obtaining a current speed and a current intake pressure of the engine under a current operating condition; Acquire a first mapping relationship, where the first mapping relationship is used to represent a mapping relationship between the engine speed, the engine intake pressure, and a theoretical NH3 emission value; According to the current speed of the engine, the current intake pressure of the engine and the first mapping relationship, the theoretical NH3 emission value corresponding to the current speed of the engine and the current intake pressure of the engine is determined as the current theoretical NH3 emission value.

3. The determination method according to claim 1, characterized in that Before obtaining the measurement deviation value, the method further includes: obtaining a current air-fuel ratio of the engine and a current exhaust temperature of the engine; Acquire a second mapping relationship, where the second mapping relationship is used to represent a mapping relationship between the air-fuel ratio of the engine, the exhaust temperature of the engine, and the NH3 emission correction value; Based on the current air-fuel ratio of the engine, the current exhaust temperature of the engine and the second mapping relationship, the NH3 emission correction value corresponding to the current air-fuel ratio of the engine and the current exhaust temperature of the engine is determined as the current NH3 emission correction value, wherein the current NH3 emission correction value is used to correct the current NH3 theoretical emission value.

4. The determination method according to claim 1, characterized in that Before obtaining the measurement deviation value, the method further includes: obtaining a current aging factor of a reaction catalyst, the reaction catalyst being used to catalyze various types of emissions in the original emissions of the engine to perform chemical reactions, the original emissions being engine emissions that have not undergone post-processing purification; Obtaining a first preset array, where the first preset array is used to represent a mapping relationship between an aging factor of the reaction catalyst and an NH3 correction factor; Determining, according to the current aging factor of the reaction catalyst and the first preset array, the NH3 correction factor corresponding to the current aging factor of the reaction catalyst as the current NH3 correction factor; The current NH3 emission correction value and the current NH3 correction factor are used to correct the current NH3 theoretical emission value to obtain the actual NH3 emission value. The actual NH3 emission value is the product of the target value and the current NH3 correction factor. The target value is the sum of the current NH3 theoretical emission value and the current NH3 emission correction value.

5. The determination method according to claim 1, characterized in that: The first preset time period includes a plurality of the fuel cut-off conditions. Before obtaining the measurement deviation value, the method further includes: Obtaining exhaust gas discharge time under each fuel cut-off operating condition within the first preset time period, wherein the exhaust gas discharge time is the time required for all exhaust gas to be completely discharged from the engine when the engine enters the fuel cut-off operating condition; After the engine begins to enter the fuel cut-off condition and the exhaust gas discharge time has passed, obtaining the preset NOx mass measurement value under each of the fuel cut-off conditions within the first preset time period to obtain a plurality of the preset NOx mass measurement values; Calculating an average value of a plurality of the preset NOx mass measurement values ​​within the first preset time period to obtain a first initial NOx mass average value; The preset NOx mass average value is determined according to a magnitude relationship between a plurality of the preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value.

6. The determination method according to claim 5, characterized in that: Determining the preset NOx mass average value according to a magnitude relationship between a plurality of the preset NOx mass measurement values ​​within the first preset time period and the first initial NOx mass average value includes: Obtaining a plurality of difference values, each difference value being a difference between the predetermined NOx mass measurement value and the first initial NOx mass average value; When the plurality of differences are all smaller than or equal to a preset difference, determining the first initial NOx mass average value as the preset NOx mass average value; When at least one of the differences is greater than the preset difference, a second initial NOx mass average value obtained in a second preset time period is determined to be the preset NOx mass average value in the first preset time period, and the second preset time period is before the first preset time period.

7. The determination method according to claim 5, characterized in that: Obtaining the exhaust gas discharge time under each of the fuel cut-off conditions within the first preset time period includes: Obtaining the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period; Obtaining a second preset array, the second preset array being used to represent a mapping relationship between the engine speed and the exhaust gas discharge time under each of the fuel cut-off conditions within the first preset time period; Based on the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period and the second preset array, a plurality of exhaust gas discharge times corresponding to the real-time speed of the engine under each of the fuel cut-off conditions within the first preset time period are determined as the exhaust gas discharge times under each of the fuel cut-off conditions.

8. A method and device for determining the NOx emission value of an engine, characterized in that: include: a first acquisition unit, configured to acquire a current NOx mass measurement value, wherein the current NOx mass measurement value is a measurement value of the NOx mass in the final emissions of the engine under the current operating condition, wherein the final emissions are the engine emissions after post-processing purification; a second acquiring unit, configured to acquire a measurement deviation value, the measurement deviation value being the sum of a current actual NH3 emission value and a preset NOx mass average value, the preset NOx mass average value being the average value of a plurality of preset NOx mass measurement values ​​corresponding to a plurality of fuel cut-off operating conditions within a first preset time period before a current moment, the preset NOx mass measurement values ​​corresponding one-to-one to the fuel cut-off operating conditions, the current actual NH3 emission value being obtained by correcting a current theoretical NH3 emission value, the current actual NH3 emission value representing the actual NH3 emission value of the engine under the current operating condition, and the current theoretical NH3 emission value being the theoretical emission value of the engine under the current operating condition; The correction unit is used to determine a current NOx actual emission value according to the current NOx mass measurement value and the measurement deviation value, where the NOx actual emission value is the difference between the NOx mass measurement value and the measurement deviation value.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for determining the NOx emission value of the engine according to any one of claims 1 to 7.

10. An electronic device, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for determining the engine NOx emission value according to any one of claims 1 to 7.

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