A nitrogen oxygen sensor fault diagnosis method, device, electronic equipment and medium

Abstract

The present invention relates to a nitrogen oxide sensor fault diagnosis method, device, electronic device, and medium, belonging to the field of automotive technology. The method comprises: obtaining a target nitrogen oxide sensor's transition time from a lean oxygen mode to a rich oxygen mode, and obtaining the number of times the target nitrogen oxide sensor transitions from the lean oxygen mode to the rich oxygen mode, upon determining that the target nitrogen oxide sensor exceeds a dew point, determining that the target nitrogen oxide sensor's oxygen concentration is enabled, determining that the engine is in a normal combustion mode, and determining that the engine exhaust flow rate is greater than a first threshold; and determining whether the target nitrogen oxide sensor is faulty based on the transition time and the number of times the target nitrogen oxide sensor transitions from the lean oxygen mode to the rich oxygen mode. The present invention defines an operating condition suitable for sensor diagnosis, and when the engine enters this operating condition, performs nitrogen oxide sensor fault diagnosis based on the minimum transition time from the lean oxygen mode to the rich oxygen mode, thereby improving the accuracy of nitrogen oxide sensor fault diagnosis.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a nitrogen oxide sensor fault diagnosis method, device, electronic equipment and medium. Background Art

[0002] NOx sensors play a vital role in the exhaust treatment systems of modern vehicles. As an essential component of the vehicle's emissions control system, they help ensure the engine runs efficiently while reducing harmful emissions.

[0003] In diesel engine aftertreatment systems, there are two main types of NOx sensors: upstream sensors (upstream oxygen sensors) and downstream sensors (downstream oxygen sensors). Upstream sensors, located in the engine's intake system, monitor the oxygen content of the air entering the engine to ensure the correct fuel-air ratio. Downstream sensors, located in the exhaust system, monitor post-combustion exhaust, particularly nitrogen oxide (NOx) emissions.

[0004] In the existing technology, nitrogen oxide sensor fault diagnosis is performed by comparing model values ​​with sensor measurement values. The model values ​​are calculated based on fuel and intake air volume. As a result, the fault diagnosis accuracy may be affected by other failure modes such as fuel or intake air volume, resulting in misdiagnosis. Summary of the Invention

[0005] In view of this, it is necessary to provide a nitrogen oxide sensor fault diagnosis method, device, electronic device and medium to solve the problem of low accuracy caused by the existing technology of sensor fault diagnosis by comparing model values ​​with sensor measurement values.

[0006] In order to solve the above problems, the present invention provides a nitrogen oxide sensor fault diagnosis method, comprising:

[0007] When it is determined that the target nitrogen oxide sensor exceeds the dew point, and the oxygen concentration of the target nitrogen oxide sensor is enabled, and the engine is determined to be in the normal combustion mode, and the engine exhaust flow rate is determined to be greater than a first threshold, obtaining a switching time of the target nitrogen oxide sensor from the lean oxygen mode to the rich oxygen mode, and obtaining a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the rich oxygen mode;

[0008] Based on the switching time and the number of times, it is determined whether the target nitrogen oxide sensor is malfunctioning.

[0009] In one possible implementation, obtaining the switching time of the target nitrogen oxide sensor from the lean oxygen mode to the rich oxygen mode includes:

[0010] Get the minimum switching time of the target NOx sensor from lean mode to rich mode.

[0011] In a possible implementation, determining whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times includes:

[0012] In a case where it is determined that the conversion time is greater than a second threshold and the number of times is greater than a third threshold, it is determined that the target nitrogen oxygen sensor is faulty.

[0013] In a possible implementation, when it is determined that the conversion time is less than a second threshold and the number of times is greater than a third threshold, it is determined that the target nitrogen oxygen sensor has no fault.

[0014] In one possible implementation, determining a target nitrogen oxide sensor dew point includes:

[0015] Obtain the operating environment temperature and dew point temperature of the target NOx sensor;

[0016] A target nitrogen oxide sensor excess dew point is determined based on the operating environment temperature and the dew point temperature.

[0017] In one possible implementation, determining the target nitrogen oxide sensor oxygen concentration enable includes:

[0018] An oxygen concentration value of a target nitrogen oxide sensor is obtained, and a target nitrogen oxide sensor oxygen concentration enable is determined based on the oxygen concentration value.

[0019] In a possible implementation, the normal combustion mode includes:

[0020] One or more of the NOx control mode and exhaust temperature management mode.

[0021] On the other hand, the present invention also provides a nitrogen oxide sensor fault diagnosis device, comprising:

[0022] a data acquisition module, configured to, upon determining that the target nitrogen oxide sensor exceeds a dew point, determining that the oxygen concentration of the target nitrogen oxide sensor is enabled, determining that the engine is in a normal combustion mode, and determining that the engine exhaust flow rate is greater than a first threshold, acquire a switching time of the target nitrogen oxide sensor from a lean oxygen mode to an oxygen rich mode, and acquire a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the oxygen rich mode;

[0023] The fault judgment module is used to determine whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times.

[0024] On the other hand, the present invention also provides an electronic device, including a memory and a processor, wherein:

[0025] The memory is used to store programs;

[0026] The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps of a nitrogen oxide sensor fault diagnosis method described in any one of the above implementations.

[0027] On the other hand, the present invention also provides a computer-readable storage medium for storing a computer-readable program or instruction, which, when executed by a processor, can implement the steps of a nitrogen oxide sensor fault diagnosis method described in any of the above-mentioned implementation methods.

[0028] The beneficial effects of the present invention are as follows: the present invention provides a method for diagnosing nitrogen oxide sensor faults. Upon determining that a target nitrogen oxide sensor exceeds a dew point, determining that the oxygen concentration of the target nitrogen oxide sensor is enabled, determining that the engine is in normal combustion mode, and determining that the engine exhaust flow rate is greater than a first threshold, the method obtains the target nitrogen oxide sensor's transition time from lean oxygen mode to rich oxygen mode, and the number of times the target nitrogen oxide sensor transitions from lean oxygen mode to rich oxygen mode; based on the transition time and the number of times, the method determines whether the target nitrogen oxide sensor is faulty. The present invention defines an operating condition suitable for sensor diagnosis, and when the engine enters this operating condition, performs nitrogen oxide sensor fault diagnosis based on the engine's minimum transition time from lean oxygen mode to rich oxygen mode, thereby improving the accuracy of nitrogen oxide sensor fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A flowchart of an embodiment of a method for diagnosing a nitrogen oxygen sensor fault provided by the present invention;

[0030] Figure 2 A schematic flow chart of an embodiment of a nitrogen and oxygen sensor fault diagnosis device provided by the present invention;

[0031] Figure 3 This is a schematic structural diagram of an embodiment of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0032] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] In the description of the embodiments of the present application, unless otherwise specified, “a plurality of” means two or more.

[0034] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or device comprising a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to these processes, methods, products or devices.

[0035] The naming or numbering of the steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0036] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] Before presenting the embodiments, the following terms are explained.

[0038] The main functions of an ECU (Electronic Control Unit) include receiving input signals from sensors or other devices, storing, calculating, analyzing and processing relevant data and information, outputting execution instructions to realize driving functions, and outputting fault information. The ECU receives input signals from sensors and other devices through input interface circuits, and then stores, calculates and analyzes them through a microprocessor. The processed data is output as execution instructions through output interface circuits to drive related equipment to work, and can also provide reference voltage to sensors.

[0039] SCR (Selective Catalytic Reduction) technology is used to reduce nitrogen oxide (NOx) emissions in flue gas. SCR uses a catalyst to react a reducing agent (such as ammonia or urea) with NOx in the flue gas, producing harmless nitrogen and water vapor.

[0040] In diesel vehicle exhaust treatment systems, SCR technology uses a catalyst to inject a reducing agent (usually ammonia or urea) to selectively reduce NOx to N2 and H2O in an oxygen-rich environment. Catalysts, which come in both precious metal and non-precious metal varieties, effectively convert NOx into harmless nitrogen and water.

[0041] How a NOx sensor works: When the ignition is turned on, the NOx sensor heats up to 100°C and waits for the ECU to transmit a "dew point" temperature signal. The dew point temperature is the temperature at which moisture in the exhaust system no longer condenses, typically set between 120°C and 140°C, depending on the exhaust system's outlet temperature. Once the NOx sensor receives the dew point temperature signal, it automatically heats up to a maximum of 800°C before commencing normal operation. At this point, the sensor begins measuring nitrogen oxides and sending them to the CAN bus. The engine ECU uses this information to monitor NOx emissions.

[0042] The functions of nitrogen oxide sensors in automobile emission control are as follows:

[0043] Monitor and control the engine's air-fuel mixture ratio: The NOx sensor can instantly capture the concentration of nitrogen oxides in the exhaust and transmit signals to the ECU through a feedback mechanism, helping the ECU to accurately control the air-fuel mixture ratio, promote efficient combustion processes, and reduce exhaust emissions.

[0044] Optimize ignition timing: Based on real-time feedback from nitrogen oxide levels, the ECU adjusts the ignition advance angle to ensure the engine operates in the optimal working state, improve fuel utilization and emissions performance.

[0045] Fault identification and protection mechanism: Once the NOx sensor detects that exhaust emissions exceed the standard or it itself malfunctions, it will quickly send a warning signal to the ECU to prevent the engine from continuing to operate in an unfavorable state and ensure driving safety.

[0046] The cornerstone of the emission control system: The monitoring and adjustment data provided by the NOx sensor provides important input information for other emission control components (such as the three-way catalytic converter and particulate filter), promoting the smooth operation of the entire emission control system.

[0047] The present invention provides a nitrogen oxygen sensor fault diagnosis method, device, electronic equipment and medium, which are described below respectively.

[0048] Figure 1 A flow chart of an embodiment of a method for diagnosing a nitrogen and oxygen sensor fault provided by the present invention is shown as follows: Figure 1 As shown, the nitrogen oxide sensor fault diagnosis method is applied to the ECU, including:

[0049] S101. When it is determined that the target nitrogen oxide sensor exceeds the dew point, the target nitrogen oxide sensor oxygen concentration is enabled, the engine is in a normal combustion mode, and the engine exhaust flow rate is greater than a first threshold, obtaining a switching time of the target nitrogen oxide sensor from a lean oxygen mode to an oxygen rich mode, and obtaining a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the oxygen rich mode;

[0050] S102: Determine whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times.

[0051] Compared to the prior art, this embodiment provides a NOx sensor fault diagnosis method. After determining that a target NOx sensor exceeds its dew point, determines that the target NOx sensor's oxygen concentration is enabled, determines that the engine is in normal combustion mode, and determines that the engine exhaust flow rate is greater than a first threshold, the method obtains the target NOx sensor's transition time from lean to rich mode, and the number of times the target NOx sensor transitions from lean to rich mode. Based on the transition time and number, the method determines whether the target NOx sensor is faulty. This method defines an operating condition suitable for sensor diagnosis, and then, when the engine enters this operating condition, performs NOx sensor fault diagnosis based on the minimum transition time from lean to rich mode, thereby improving the accuracy of NOx sensor fault diagnosis.

[0052] It should be noted that the present invention is applicable to diesel engines using the SCR technology. It is understandable that the present invention is also applicable to other types of vehicles that require the use of the SCR technology.

[0053] In a specific embodiment of the present invention, the target NOx sensor is a downstream NOx sensor, located in the exhaust system, which monitors post-combustion exhaust, particularly nitrogen oxide (NOx) emissions. This embodiment of the present invention determines whether the downstream NOx sensor's measured value is reasonable based on whether the transition time of the downstream NOx sensor's mode change is greater than a preset threshold under specific operating conditions. If reasonable, the downstream NOx sensor is determined to be fault-free; otherwise, the downstream NOx sensor is determined to be faulty.

[0054] In some embodiments of the present invention, obtaining the switching time of the target nitrogen oxide sensor from the lean oxygen mode to the rich oxygen mode includes:

[0055] Get the minimum switching time of the target NOx sensor from lean mode to rich mode.

[0056] Specifically, let's first explain the lean and rich modes. Lean mode means the exhaust oxygen concentration reaches a first preset value, at which point the sensor output voltage is low. Rich mode means the exhaust oxygen concentration reaches a second preset value, at which point the sensor output voltage is high.

[0057] Because NOx sensors accurately measure the oxygen content in vehicle exhaust and control the engine's combustion state in real time, they play a vital role in reducing vehicle emissions. A malfunctioning NOx sensor can lead to poor engine acceleration, increased fuel consumption, and compromised emissions performance. Therefore, ensuring the correctness of NOx sensor readings is crucial.

[0058] The preceding describes lean and rich modes. The following describes the transition time. During a driving cycle (from vehicle power-up to shutdown), the target NOx sensor detects several transitions from lean to rich mode. Each transition has a transition time, and the minimum transition time is determined.

[0059] In some embodiments of the present invention, determining whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times includes:

[0060] In a case where it is determined that the conversion time is greater than a second threshold and the number of times is greater than a third threshold, it is determined that the target nitrogen oxygen sensor is faulty.

[0061] In some embodiments of the present invention, when it is determined that the conversion time is less than a second threshold and the number of times is greater than a third threshold, it is determined that the target nitrogen oxide sensor has no fault.

[0062] It should be noted that a NOx sensor over-dew point occurs when the sensor's operating temperature in the exhaust system reaches or exceeds its dew point, causing the sensor to malfunction or even be damaged. The dew point is the temperature at which moisture in the exhaust system condenses. Above this temperature, moisture condenses into liquid water, potentially damaging the sensor.

[0063] In some embodiments of the present invention, determining a target nitrogen oxide sensor dew point includes:

[0064] Obtain the operating environment temperature and dew point temperature of the target NOx sensor;

[0065] A target nitrogen oxide sensor excess dew point is determined based on the operating environment temperature and the dew point temperature.

[0066] It should be noted that enabling the NOx sensor's oxygen concentration means that the NOx sensor can achieve more precise measurement and control of nitrogen oxide (NOx) concentration in engine exhaust by measuring oxygen concentration. The NOx sensor determines the NOx content by measuring the difference between oxygen and NOx concentrations in exhaust gas and transmits this information to the engine control unit (ECU), thereby adjusting the engine's operating state and reducing exhaust emissions.

[0067] In some embodiments of the present invention, determining whether the target nitrogen oxide sensor oxygen concentration is enabled includes:

[0068] An oxygen concentration value of a target nitrogen oxide sensor is obtained, and an oxygen concentration enable of the target nitrogen oxide sensor is determined based on the oxygen concentration value, that is, it is determined that the target nitrogen oxide sensor is in a normal working state.

[0069] It should be noted that the primary purpose of NOx control mode is to reduce nitrogen oxide (NOx) emissions. Specifically, NOx is formed when nitrogen and oxygen combine at high temperatures (above 1370°C). Therefore, lowering combustion temperatures can effectively reduce NOx generation. The exhaust gas recirculation (EGR) system is a key technology for achieving this goal. The EGR system directs some of the engine's exhaust gas into the intake manifold, where it mixes with fresh air before entering the cylinders. The CO2 in the exhaust gas absorbs heat, thereby lowering combustion temperatures and reducing NOx generation. However, controlling the EGR system requires a balance. Excessive exhaust gas recirculation can lead to poor ignition of the mixture, increased fuel consumption, and reduced power. Therefore, EGR control must minimize NOx emissions while ensuring proper engine operation. The primary goal of exhaust temperature management mode is to manage engine exhaust temperature, ensuring optimal engine operation, thereby improving fuel economy and engine performance. Only when the engine is at the appropriate temperature can it maintain optimal operating conditions, resulting in more complete combustion and higher efficiency. If the engine temperature is too low, it will lead to incomplete fuel combustion, increased friction, and higher fuel consumption; while excessive temperatures will damage components and reduce the lubrication effectiveness of the oil. 2 Therefore, exhaust temperature management optimizes the cooling system to ensure that the engine is neither too cold nor too hot, always maintaining optimal conditions. Exhaust temperature management not only focuses on thermal management at high temperatures but also includes the warm-up process at low temperatures, ensuring efficient engine operation under various operating conditions.

[0070] In some embodiments of the present invention, the normal combustion mode includes:

[0071] One or more of the NOx control mode and exhaust temperature management mode.

[0072] In a specific embodiment of the present invention, the ECU obtains the combustion mode of the engine by acquiring data from sensors on the cylinders.

[0073] The present invention determines the rationality of the downstream NOx sensor measurement value, that is, whether the downstream NOx sensor has a fault, based on the fact that the response time of the downstream NOx sensor mode change is greater than the calibration value under special operating conditions. This solves the problem of low accuracy caused by comparing the oxygen content measurement value of the downstream NOx sensor with the model calculated value in the prior art.

[0074] In order to better implement a nitrogen oxide sensor fault diagnosis method in an embodiment of the present invention, based on a nitrogen oxide sensor fault diagnosis method, correspondingly, as shown in FIG. Figure 2 As shown, an embodiment of the present invention further provides a nitrogen oxide sensor fault diagnosis device, a nitrogen oxide sensor fault diagnosis device 200 including:

[0075] a data acquisition module 201 for acquiring a switching time of the target nitrogen oxide sensor from a lean oxygen mode to an oxygen rich mode, and acquiring a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the oxygen rich mode, when determining that the target nitrogen oxide sensor exceeds a dew point, determining that the oxygen concentration of the target nitrogen oxide sensor is enabled, determining that the engine is in a normal combustion mode, and determining that the engine exhaust flow rate is greater than a first threshold;

[0076] The fault judgment module 202 is configured to determine whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times.

[0077] The nitrogen oxide sensor fault diagnosis device 200 provided in the above embodiment can implement the technical solution described in the above embodiment of the nitrogen oxide sensor fault diagnosis method. The specific implementation principles of the above modules or units can be found in the corresponding contents in the above embodiment of the nitrogen oxide sensor fault diagnosis method, which will not be repeated here.

[0078] like Figure 3 As shown, the present invention also provides an electronic device 300. The electronic device 300 includes a processor 301, a memory 302 and a display 303. Figure 3 Only some of the components of the electronic device 300 are shown, but it should be understood that implementation of all of the shown components is not required, and more or fewer components may be implemented instead.

[0079] In some embodiments, the processor 301 may be a central processing unit (CPU), a microprocessor, or other data processing chip, configured to execute program code or process data stored in the memory 302 , such as a nitrogen oxide sensor fault diagnosis method of the present invention.

[0080] In some embodiments, processor 301 may be a single server or a server group. The server group may be centralized or distributed. In some embodiments, processor 301 may be local or remote. In some embodiments, processor 301 may be implemented on a cloud platform. In some embodiments, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, multiple clouds, or any combination thereof.

[0081] In some embodiments, the memory 302 may be an internal storage unit of the electronic device 300, such as a hard disk or memory of the electronic device 300. In other embodiments, the memory 302 may also be an external storage device of the electronic device 300, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 300.

[0082] Furthermore, the memory 302 may include both an internal storage unit of the electronic device 300 and an external storage device. The memory 302 is used to store application software installed in the electronic device 300 and various data.

[0083] In some embodiments, display 303 can be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 303 is used to display information on electronic device 300 and to display a visual user interface. Components 301-303 of electronic device 300 communicate with each other via a system bus.

[0084] In one embodiment, when the processor 301 executes a nitrogen oxide sensor fault diagnosis program in the memory 302, the following steps may be implemented:

[0085] When it is determined that the target nitrogen oxide sensor exceeds the dew point, and the oxygen concentration of the target nitrogen oxide sensor is enabled, and the engine is determined to be in the normal combustion mode, and the engine exhaust flow rate is determined to be greater than a first threshold, obtaining a switching time of the target nitrogen oxide sensor from the lean oxygen mode to the rich oxygen mode, and obtaining a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the rich oxygen mode;

[0086] Based on the switching time and the number of times, it is determined whether the target nitrogen oxide sensor is malfunctioning.

[0087] It should be understood that, when the processor 301 executes a nitrogen oxygen sensor fault diagnosis program in the memory 302 , in addition to the above functions, it can also implement other functions. For details, please refer to the description of the corresponding method embodiment above.

[0088] Furthermore, the embodiment of the present invention does not specifically limit the type of the electronic device 300 mentioned. The electronic device 300 may be a portable electronic device such as a mobile phone, a tablet computer, a personal digital assistant (PDA), a wearable device, a laptop computer, or the like. Exemplary embodiments of portable electronic devices include but are not limited to portable electronic devices equipped with IOS, Android, Microsoft, or other operating systems. The above-mentioned portable electronic devices may also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, the electronic device 300 may not be a portable electronic device, but a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0089] Those skilled in the art will appreciate that all or part of the process steps of the above-described embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0090] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for diagnosing faults of nitrogen and oxygen sensors, characterized in that: include: After determining that the target nitrogen oxide sensor exceeds a dew point, obtaining an oxygen concentration value of the target nitrogen oxide sensor, determining that the target nitrogen oxide sensor oxygen concentration is enabled based on the oxygen concentration value, determining that the engine is in a normal combustion mode, and determining that the engine exhaust flow rate is greater than a first threshold, obtaining a switching time of the target nitrogen oxide sensor from a lean oxygen mode to an oxygen rich mode, and obtaining a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the oxygen rich mode, wherein the lean oxygen mode refers to when the oxygen concentration in the exhaust gas reaches a first preset value, and the oxygen rich mode refers to when the oxygen concentration in the exhaust gas reaches a second preset value; Based on the switching time and the number of times, it is determined whether the target nitrogen oxide sensor is malfunctioning.

2. The nitrogen oxide sensor fault diagnosis method according to claim 1, characterized in that: Obtain the target NOx sensor's transition time from lean mode to rich mode, including: Get the minimum switching time of the target NOx sensor from lean mode to rich mode.

3. The nitrogen oxide sensor fault diagnosis method according to claim 2, characterized in that: The determining whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times includes: In a case where it is determined that the conversion time is greater than a second threshold and the number of times is greater than a third threshold, it is determined that the target nitrogen oxygen sensor is faulty.

4. The nitrogen oxide sensor fault diagnosis method according to claim 1, characterized in that: In a case where it is determined that the conversion time is less than the second threshold and the number of times is greater than a third threshold, it is determined that the target nitrogen oxygen sensor has no fault.

5. The nitrogen oxide sensor fault diagnosis method according to claim 1, characterized in that: Determine the target NOx sensor dew point, including: Obtain the operating environment temperature and dew point temperature of the target NOx sensor; A target nitrogen oxide sensor excess dew point is determined based on the operating environment temperature and the dew point temperature.

6. The nitrogen oxide sensor fault diagnosis method according to claim 1, characterized in that: The normal combustion mode includes: One or more of the NOx control mode and exhaust temperature management mode.

7. A nitrogen oxide sensor fault diagnosis device, characterized in that: include: a data acquisition module for, upon determining that the target nitrogen oxide sensor exceeds a dew point, acquiring an oxygen concentration value of the target nitrogen oxide sensor, determining that the oxygen concentration of the target nitrogen oxide sensor is enabled based on the oxygen concentration value, determining that the engine is in a normal combustion mode, and determining that the engine exhaust flow rate is greater than a first threshold, acquiring a switching time of the target nitrogen oxide sensor from a lean oxygen mode to an oxygen rich mode, and acquiring a number of times the target nitrogen oxide sensor switches from the lean oxygen mode to the oxygen rich mode, wherein the lean oxygen mode refers to when the oxygen concentration in the exhaust gas reaches a first preset value, and the oxygen rich mode refers to when the oxygen concentration in the exhaust gas reaches a second preset value; The fault judgment module is used to determine whether the target nitrogen oxide sensor is faulty based on the conversion time and the number of times.

8. An electronic device, characterized in that: comprising a memory and a processor, wherein, The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps of the nitrogen oxide sensor fault diagnosis method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that Used to store computer-readable programs or instructions, which, when executed by a processor, can implement the steps of the nitrogen oxide sensor fault diagnosis method described in any one of claims 1 to 6.

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