A scr deterioration fault simulation method and system

Abstract

This invention relates to a method and system for simulating SCR degradation failure. The method includes the following steps: S1: Obtaining engine operating parameters and obtaining NO. X Raw NO measured by sensor X Concentration report; S2: Based on the preset SCR emission reduction target value and engine operating parameters, NO concentration is reduced by SCR. X The demand concentration model yields the NO required to simulate the SCR degradation state. X Demand concentration; S3: to reduce the original NO X Characterization of NO in concentration reports X Replace the original concentration data with NO X S4: The required concentration data is used to generate a simulated data message; S5: The simulated data message is sent to the engine ECU to trigger the SCR degradation fault. This method modifies the NO... X The sensor data message content simulates the SCR deterioration state, replacing the traditional process of manufacturing and replacing physically deteriorated parts, shortening the preparation cycle for OBD fault verification, and saving material and labor costs incurred in manufacturing deteriorated parts.

Description

Technical Field

[0001] This manual relates to the field of vehicle emission testing technology, and in particular to a method and system for simulating SCR degradation failure. Background Technology

[0002] SCR (Selective Catalytic Reduction) is a crucial after-treatment system in diesel engines that uses a urea solution to convert nitrogen oxides into harmless substances. With increasingly stringent emission regulations, the performance stability of the catalytic converter directly impacts the vehicle's compliance. Therefore, conducting vehicle-wide verification of SCR degradation failures is particularly important. This verification not only ensures that the OBD system accurately monitors SCR performance decline but also identifies malicious tampering with vehicle emissions, thus guaranteeing vehicle compliance, mitigating potential recall risks, and identifying malicious tampering.

[0003] When conducting functional verification of SCR deterioration faults in a vehicle, the current fault simulation method is to create a deteriorated SCR and replace the normal SCR on the engine to create an SCR deterioration fault. However, the manufacturing process of deteriorated SCR parts requires long-term high-temperature thermal aging treatment and repeated emission tests at different stages of aging to verify the performance of the deteriorated parts. This results in a complex, long-cycle, and costly manufacturing process for deteriorated parts. Furthermore, deteriorated parts have limited functionality, poor versatility, and are difficult to replace. Summary of the Invention

[0004] This specification provides a method and system for simulating SCR degradation failures, which solves the problem of high cost in existing SCR failure simulation technologies.

[0005] The following technical solution is adopted in this specification: A method for simulating SCR degradation failure includes the following steps: S1: Obtain engine operating parameters and obtain NO. X Raw NO measured by sensor X Concentration report; S2: Based on the preset SCR emission reduction target value and the engine operating parameters, reduce NO emissions through SCR. X The demand concentration model yields the NO required to simulate the SCR degradation state. X Demand concentration; S3: The original NO X Characterization of NO in concentration reports X The original concentration data was replaced with the NO concentration data. X The data on demand concentration is used to generate simulated data messages; S4: Send the simulated data message to the engine ECU to trigger the SCR deterioration fault.

[0006] Based on the aforementioned technical means, this method simulates the SCR degradation state by modifying message content, replacing the traditional physical degraded component manufacturing and replacement process. This shortens the preparation cycle for OBD fault verification, significantly reduces material and labor costs incurred in manufacturing degraded components, and lowers the operational difficulty of on-site hardware replacement. Furthermore, it can simulate the NO degradation state of the SCR. X The demand concentration model obtains the NO required to simulate the SCR degradation state. X Demand concentration provides an efficient and flexible simulation method for functional verification of SCR deterioration faults in whole vehicles.

[0007] Furthermore, the engine operating parameters include instantaneous engine speed, engine reference torque, engine output torque percentage, engine friction torque percentage, and NO. X Density and exhaust density ratio, instantaneous intake air mass flow rate, and instantaneous fuel mass flow rate.

[0008] Furthermore, the NO X The specific method for calculating the required concentration is as follows: , in, c i Indicates NO X Demand concentration, k 1,i This represents the first correction factor. k 2,i This represents the second correction factor. e Indicates the deterioration of emission targets NO X Compared to emissions, n i Indicates the instantaneous engine speed, M ref Indicates the engine's reference torque, r act,i Indicates the percentage of engine output torque. r fri,i Indicates the percentage of engine friction torque. u NOx Indicates NO X Density and exhaust density ratio, q maw,i Indicates instantaneous intake mass flow rate and q mf,i This indicates the instantaneous fuel mass flow rate.

[0009] Furthermore, S3 also includes the NO X Demand concentration data is corrected, including drag correction, idle speed correction, 300s moving window correction, and power base window moving correction.

[0010] Furthermore, the first correction coefficient is obtained through the 300s moving window correction, specifically obtained as follows: , in, W 300,i This indicates the engine output power during a 300s moving window. m 300,i This indicates the NOx mass emissions over a 300s moving window.

[0011] Based on the aforementioned technical methods, by continuously calculating the emission ratio within the window and dynamically adjusting the first correction coefficient, it is ensured that the simulated NO levels are within any given time period. X The required concentration can be stabilized near the preset SCR deterioration emission target value.

[0012] Furthermore, the second correction coefficient is obtained through the work base window shift correction, specifically obtained as follows: , in, W WHTC,i This indicates the engine output power displayed on the power base window. m WHTC,i Indicates the power base window NO X Quality emissions.

[0013] Based on the above technical means, the correction is made based on the window of engine output power, which effectively eliminates the interference of idling and low load conditions on the statistical results, making the calculation of the second correction coefficient more reflective of the engine's real emission status and ensuring the stability of the simulated degradation effect.

[0014] Furthermore, if the 300s moving window and the power base window overlap, only the power base window will be corrected.

[0015] Based on the above technical means, when the 300s moving window and the power base window overlap, only the power base window is corrected, which avoids the logical confusion or coefficient oscillation caused by the simultaneous influence of two correction algorithms on the data, and ensures the simplicity and effectiveness of the correction process / result.

[0016] Furthermore, the drag correction includes: when the engine output torque percentage is less than the engine friction torque percentage, adjusting the NO... X The required concentration is set to 0.

[0017] Based on the above technical means, the reverse towing correction sets the NOx demand concentration under the reverse towing condition (when the percentage of engine output torque is less than the percentage of engine friction torque) to zero, which avoids the engine generating unreasonable virtual emissions when being reverse-towed, and ensures that the simulation data conforms to the physical laws of actual vehicle operation.

[0018] Furthermore, the idle speed correction includes: when the engine output torque percentage equals the engine friction torque percentage, the required NOx concentration is the original NO... X concentration.

[0019] Based on the aforementioned technical methods, the idle speed correction sets the required NOx concentration under idle conditions to the original NOx concentration, thus preventing SCR from degrading NO. X The demand concentration model calculates distorted demand concentrations under low exhaust energy conditions, increasing the realism of the simulated data messages during the idling phase.

[0020] Furthermore, an SCR degradation failure simulation system is also provided, for using the above-mentioned SCR degradation failure simulation method, including: NOx sensor is used to collect the raw NOx concentration in exhaust gas and generate NO. X Original CAN message from the sensor; The system includes a CAN acquisition and processing module and an engine ECU. The CAN acquisition and processing module has a first CAN channel and a second CAN channel. The first CAN channel is communicatively connected to the NOx sensor and is used to receive raw CAN messages. The second CAN channel is used to communicate with the CAN network of the engine ECU. A control terminal is communicatively connected to the CAN acquisition and processing module. The control terminal stores a computer program. When the computer program is executed, it implements the steps of the method as described in any one of claims 1 to 9, processes the original CAN message, generates a simulated data message, and forwards it to the engine ECU through the CAN acquisition and processing module.

[0021] Based on the above technical means, the CAN acquisition and processing module in this system has a first CAN channel and a second CAN channel. The first CAN channel is communicatively connected to the NOx sensor and is used to receive NO. X The first CAN channel is used to communicate with the engine ECU via the CAN network. By using the first CAN channel and the second CAN channel, the control terminal can intercept and modify the original message sent by the NOx sensor to the ECU online, and forward the modified data message to the ECU. Moreover, it can simulate different gas concentrations and sensor self-diagnostic faults (such as vacancy, voltage abnormality, internal circuit fault) by only updating the computer program in the control terminal, thereby improving the utilization rate and versatility of the equipment.

[0022] This design enables fault injection at the signal layer without requiring any physical modifications to the engine, aftertreatment system, or vehicle wiring harness, completely avoiding the high costs and complex operations associated with replacing degraded SCR components.

[0023] The above-mentioned technical solutions adopted in this specification can achieve the following beneficial effects: This method simulates SCR degradation by modifying data message content, replacing the traditional process of manufacturing and replacing physically degraded parts. This shortens the preparation cycle for OBD fault verification, significantly reduces material and labor costs associated with manufacturing degraded parts, and lowers the operational difficulty of replacing hardware on-site. Furthermore, it can simulate NO degradation through SCR. X The demand concentration model obtains the NO required to simulate the SCR degradation state. X Demand concentration provides an efficient and flexible simulation method for functional verification of SCR deterioration faults in whole vehicles. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of this specification and form part of this specification, illustrate exemplary embodiments and are used to explain this specification, but do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall process of Example 1; Figure 2 This is a schematic diagram of the overall structure of Example 2.

[0025] Figure label: The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The same or similar reference numerals correspond to the same or similar components. The terms describing positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.

[0027] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0028] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0029] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0030] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium.

[0031] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0032] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0033] Example 1 like Figure 1 As shown, this embodiment provides a method for simulating SCR degradation failure, which includes the following steps: S1: Obtain engine operating parameters and obtain NO. X Raw NO measured by sensor X Concentration report; S2: Based on the preset SCR emission reduction target value and the engine operating parameters, reduce NO emissions through SCR.X The demand concentration model yields the NO required to simulate the SCR degradation state. X Demand concentration; In this embodiment, SCR degrades NO X The formula for calculating the demand concentration model is: , in, c i Indicates NO X Demand concentration, k 1,i This represents the first correction factor. k 2,i This represents the second correction factor. e Indicates the deterioration of emission targets NO X Compared to emissions, n i Indicates the instantaneous engine speed, M ref Indicates the engine's reference torque, r act,i Indicates the percentage of engine output torque. r fri,i Indicates the percentage of engine friction torque, u NOx Indicates NO X Density and exhaust density ratio, q maw,i Indicates instantaneous intake mass flow rate and q mf,i This indicates the instantaneous fuel mass flow rate.

[0034] In this embodiment, step S3 further includes processing the NO. X The demand concentration data is corrected, including drag correction, idle speed correction, 300s moving window correction, and power base window moving correction.

[0035] In this preferred embodiment, the back-dragging correction specifically refers to: when the vehicle is in a back-dragging state during actual operation, causing the engine output torque percentage to be less than the engine friction torque percentage, if... If it is less than 0, then calculate the NO. X The required concentration is set to 0.

[0036] In this preferred embodiment, the idle speed correction specifically involves: when the vehicle is idling or has no power output during actual operation, causing the engine output torque percentage to equal the engine friction torque percentage; if it equals 0, then the NO is calculated. X The demand concentration data uses raw NO X The first 1-2 bytes of the raw NO in the sensor data message (hexadecimal) X concentration; In this embodiment, the 300s moving window correction specifically refers to: to ensure the NO X The demand concentration has remained at NO X At the required concentration, starting from 300s, calculate the original NO for each 300s window. X Concentration and NO X The ratio of demand concentration This ratio is used as the first correction factor, which is set to 1 before 300 seconds; when the window moves after 300 seconds, the engine output power... When the value is less than or equal to 0, the first correction factor is treated as 1; The first correction coefficient is obtained through the 300s moving window correction, specifically as follows: , in, W 300,i This indicates the engine output power during a 300s moving window. m 300,i This indicates the NOx mass emissions over a 300s moving window.

[0037] In this embodiment, the power base window movement correction specifically involves: to ensure the NO X The demand concentration has remained at NO X To avoid the impact of low load and idling conditions on the calculated SCR emission deterioration target value at the required concentration, starting from 1 WHTC cycle power, a moving average method is used to calculate the original NO in the WHTC cycle power window. X The ratio of the concentration to the target value for SCR deterioration emissions This ratio is used as a correction factor, and the correction factor is treated as 1 before 1 times the WHTC cycle power. The second correction coefficient is obtained through the work base window shift correction, specifically as follows: , in, W WHTC,i This indicates the engine output power displayed on the power base window. m WHTC,i Indicates the power base window NO X Quality emissions.

[0038] In this embodiment, if the 300s moving window and the power base window overlap, only the power base window is corrected. This avoids logical confusion or coefficient oscillations caused by two correction algorithms simultaneously affecting the data, ensuring the simplicity and effectiveness of the correction process / result. S3: The original NO XCharacterization NO in sensor data messages X The original concentration data was replaced with the NO concentration data. X The data on demand concentration is used to generate simulated data messages; S4: Send the simulated data message to the engine ECU to trigger the SCR deterioration fault.

[0039] In summary, this embodiment simulates SCR degradation by modifying data message content, replacing the traditional physical degraded component manufacturing and replacement process. This shortens the preparation cycle for OBD fault verification, significantly reduces material and labor costs associated with manufacturing degraded components, and lowers the operational difficulty of on-site hardware replacement. Furthermore, it can simulate NO degradation through SCR. X The demand concentration model obtains the NO required to simulate the SCR degradation state. X Demand concentration provides an efficient and flexible simulation method for functional verification of SCR deterioration faults in whole vehicles.

[0040] Example 2 This embodiment is similar to Embodiment 1, and the same parts are described in Embodiment 1. The following description only focuses on the improved parts.

[0041] like Figure 2 As shown, this embodiment provides an SCR degradation failure simulation system for using the above-described SCR degradation failure simulation method, including: NOx sensor, used to collect the raw NOx concentration in exhaust gas and generate raw NO. X Sensor CAN data messages; The system includes a CAN acquisition and processing module and an engine ECU. The CAN acquisition and processing module has a first CAN channel and a second CAN channel. The first CAN channel is communicatively connected to the NOx sensor and is used to receive raw CAN messages. The second CAN channel is used to communicate with the CAN network of the engine ECU. A control terminal is communicatively connected to the CAN acquisition and processing module. The control terminal stores a computer program, which, when executed, implements the steps of the method as described in any one of claims 1 to 9, processing the original NO. X The sensor CAN messages are processed to generate analog data messages, which are then forwarded to the engine ECU via the CAN acquisition and processing module.

[0042] To ensure that this system can simulate the original vehicle's NO... XIn practice, the complete communication process between the sensor and the ECU requires system initialization to be completed before the engine ECU is powered on. Specifically, before the vehicle ECU is powered on, the CAN message parsing and transformation software in the control terminal transmits the data from the first CAN channel of the CAN acquisition and processing module to the NO... X The sensor's specific CAN ID (e.g., 18FEDF00) continuously sends NO at 250ms intervals. X The sensor dew point check completion message is used to simulate the original vehicle ECU's dew point check process, thereby ensuring the NO... X The sensor was able to start heating and enter working mode normally. At the same time, the system's time was reset to zero, completing system initialization. Subsequent data calculations and real-time display will then begin from this zero point.

[0043] Based on this, the system can execute multiple fault simulation modes: SCR degradation fault simulation implementation method one: Set the SCR degradation emission target value to 1.2g / (kW·h) or set it freely as needed, where the engine instantaneous speed is... Engine reference torque Engine output torque percentage Engine friction torque percentage Instantaneous intake mass flow rate Instantaneous fuel mass flow rate NO is obtained from the ECU via the first CAN channel according to the corresponding OBD communication protocol of the engine ECU; NO is calculated using the SCR deterioration NOx demand concentration model. X The required concentration is transmitted as NO to the engine ECU. X Concentration. The computer program on the control terminal replaces the first two bytes of the original CAN message (CAN ID 18F00F52) in hexadecimal format with the calculated NO value according to the message parsing rules. X If the required concentration is high, such as when the new 1-2 bytes of hexadecimal data exceed FFFF, it is executed as FFFF, while the remaining message bytes remain unchanged. The data is continuously sent to the engine ECU via the second CAN channel of the CAN acquisition and processing module to CAN ID 18F00F52 at 50ms intervals, thereby simulating SCR deterioration faults.

[0044] SCR Deterioration Failure Simulation Implementation Method Two: Based on the analysis of SCR deterioration failure monitoring principles, it was found that SCR deterioration failures are mainly caused by NO downstream of the SCR system. X The data fed back from the sensors to the ECU is used to calculate the conversion efficiency of the SCR catalyst for fault monitoring. This can be achieved by tampering with the NO... X NO sent by downstream sensors to the ECU XEmissions data, by increasing the data size, reduces the conversion efficiency of the engine ECU's calculations, thus enabling fault simulation. The original message (hexadecimal): CAN ID 18F00F52, received by the first CAN channel of the CAN acquisition and processing module, is parsed using computer CAN message parsing software according to message parsing rules to form the NO... X Concentration, unit ppm; then NO X The concentration value can be amplified by 4, 6, 8, or 10 times, with the amplification factor selectable. After amplification, the data is converted into 1-2 bytes of a hexadecimal message. If the new 1-2 bytes of hexadecimal data exceed FFFF, it is executed as FFFF, while the remaining message bytes remain unchanged. The amplified 1-2 bytes are combined with the remaining bytes to form a new CAN message, which is continuously sent to the engine ECU via the second CAN channel of the CAN acquisition and processing module to CAN ID 18F00F52 at 50ms intervals, thereby simulating SCR deterioration faults.

[0045] In other embodiments, if it is necessary to simulate an oxygen concentration reasonableness fault, it is only necessary to modify the oxygen concentration transmitted to the engine ECU proportionally in the same way as the above steps to simulate an oxygen concentration reasonableness fault.

[0046] NO X Sensor empty fault simulation method: NO X Sensor empty fault based on monitoring NO X The change in oxygen concentration measured by the sensor is achieved when NO X If the oxygen concentration measured by the sensor remains close to the atmospheric oxygen concentration, the fault indicator light will be activated, a fault code will be stored, and NO will be indicated. X The sensor is malfunctioning due to a false negative. Therefore, the NO code was modified. X The oxygen concentration data sent by the sensor to the ECU is kept close to 20%, which enables the simulation of faults.

[0047] NO X The sensor's internal power supply, heating, short circuit, open circuit, and other self-diagnostic fault simulation methods are as follows: The CAN ID (raw message) received by the CAN acquisition and processing module via the first CAN channel is processed through the program stored in the control terminal: 18F00F52 (for upstream NO...). X During sensor fault simulation, a hexadecimal message with CAN ID 18F00E51 is converted into a corresponding fault data message based on the fault failure mode and sent to the engine ECU, thereby achieving NO. X Simulation of sensor-related self-diagnostic faults. Example: Downstream NO XThe fault simulation of unreasonable sensor power supply voltage is a self-diagnostic fault of the sensor. Regardless of the message received by the first CAN channel with CAN ID: 18F00F52, the fault data message is set to FF FF FF FF00 1F 1F 1F according to the fault failure mode. The second CAN channel of the CAN acquisition and processing module continuously sends the CAN ID (here, the simulated fault data message): 18F00F52 to the ECU at 50ms intervals, thereby realizing the fault simulation.

[0048] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for simulating SCR degradation failure, characterized in that, Includes the following steps: S1: Obtain engine operating parameters and obtain NO. X Raw NO measured by sensor X Concentration report; S2: Based on the preset SCR emission reduction target value and the engine operating parameters, reduce NO emissions through SCR. X The demand concentration model yields the NO required to simulate the SCR degradation state. X Demand concentration; S3: The original NO X Characterization of NO in concentration reports X The original concentration data was replaced with the NO concentration data. X The data on demand concentration is used to generate simulated data messages; S4: Send the simulated data message to the engine ECU to trigger the SCR deterioration fault.

2. The SCR degradation failure simulation method according to claim 1, characterized in that, The engine operating parameters include engine instantaneous speed, engine reference torque, engine output torque percentage, engine friction torque percentage, and NO. X Density and exhaust density ratio, instantaneous intake air mass flow rate, and instantaneous fuel mass flow rate.

3. The SCR degradation failure simulation method according to claim 1, characterized in that, The NO X The specific method for calculating the required concentration is as follows: ， in, c i Indicates NO X Demand concentration, k 1,i This represents the first correction factor. k 2,i This represents the second correction factor. e Indicates the deterioration of emission targets NO X Compared to emissions, n i Indicates the instantaneous engine speed, M ref Indicates the engine's reference torque, r act,i Indicates the percentage of engine output torque. r fri,i Indicates the percentage of engine friction torque, u NOx Indicates NO X Density and exhaust density ratio, q maw,i Indicates instantaneous intake mass flow rate and q mf,i This indicates the instantaneous fuel mass flow rate.

4. The SCR degradation failure simulation method according to claim 3, characterized in that, S3 also includes the NO X The demand concentration data is corrected, including drag correction, idle speed correction, 300s moving window correction, and power base window moving correction.

5. The SCR degradation failure simulation method according to claim 4, characterized in that, The first correction coefficient is obtained through the 300s moving window correction, specifically as follows: ， in, W 300,i This indicates the engine output power during a 300s moving window. m 300,i This indicates the NOx mass emissions over a 300s moving window.

6. The SCR degradation failure simulation method according to claim 4, characterized in that, The second correction coefficient is obtained through the work base window shift correction, specifically as follows: ， in, W WHTC,i This indicates the engine output power displayed on the power base window. m WHTC,i Indicates the power base window NO X Quality emissions.

7. The SCR degradation failure simulation method according to claim 4, characterized in that, If the 300s moving window and the power base window overlap, then only the power base window is corrected.

8. The SCR degradation failure simulation method according to claim 4, characterized in that, The drag correction includes: when the engine output torque percentage is less than the engine friction torque percentage, the NO... X The required concentration is set to 0.

9. The SCR degradation failure simulation method according to claim 4, characterized in that, The idle speed correction includes: when the engine output torque percentage equals the engine friction torque percentage, the required NOx concentration is the original NO... X concentration.

10. An SCR degradation failure simulation system, used to employ the SCR degradation failure simulation method according to any one of claims 1-9, characterized in that, include: The NOx sensor is used to collect the raw NOx concentration in the exhaust gas and generate the raw CAN message. A CAN acquisition and processing module and an engine ECU are included. The CAN acquisition and processing module has a first CAN channel and a second CAN channel. The first CAN channel is communicatively connected to the NOx sensor and is used to receive NO. X Original CAN message from the sensor; The second CAN channel is used for communication with the engine ECU's CAN network; A control terminal is communicatively connected to the CAN acquisition and processing module. The control terminal stores a computer program. When the computer program is executed, it implements the steps of the method as described in any one of claims 1 to 9, processes the original CAN message, generates a simulated data message, and forwards it to the engine ECU through the CAN acquisition and processing module.

Images