Engine aftertreatment efficiency diagnostic method and apparatus

Abstract

The present disclosure provides an engine aftertreatment efficiency diagnosis method and device, and relates to the technical field of engines, wherein the method comprises the following steps: acquiring current actual state parameters of a vehicle; judging whether a current working condition of the vehicle meets a preset efficiency diagnosis trigger condition based on the actual state parameters; when the current working condition meets the efficiency diagnosis trigger condition, starting a diagnosis parameter acquisition process matched with the efficiency diagnosis trigger condition, so as to generate a diagnosis parameter related to the conversion efficiency of nitrogen oxides by a three-way catalyst based on the front oxygen sensor data and the nitrogen oxides sensor data in the actual state parameters, wherein the nitrogen oxides sensor is located at the output end of the three-way catalyst; starting an aftertreatment efficiency generation process matched with the efficiency diagnosis trigger condition, so as to generate an engine aftertreatment efficiency diagnosis result based on the diagnosis parameter. The method can improve the reliability of the diagnosis result by installing a nitrogen oxides sensor to read the nitrogen oxides emission concentration in real time and use it for efficiency diagnosis.

Description

Technical Field

[0001] This disclosure belongs to the field of engine technology, specifically relating to a method and apparatus for diagnosing engine aftertreatment efficiency. Background Technology

[0002] The three-way catalytic converter (TWC) is a core component of the engine aftertreatment system, used to efficiently convert polluting exhaust gases from fuel combustion into harmless gases. However, with increased usage time, TWCs experience varying degrees of performance degradation, leading to a decrease in their efficiency in converting exhaust pollutants and consequently, excessive engine emissions. Therefore, on-board diagnostic systems need to periodically diagnose the engine aftertreatment efficiency.

[0003] The existing technology calculates the total oxygen storage capacity (TWC) using a front oxygen sensor located at the input of the three-way catalytic converter and a rear oxygen sensor located at the output. Based on the TWC level, it indirectly assesses the engine's aftertreatment efficiency. However, this technology is an indirect diagnostic method, only able to indirectly infer engine aftertreatment efficiency through TWC calculations, resulting in low accuracy. Furthermore, this method cannot directly monitor nitrogen oxide (NOx) emission concentrations, making it difficult to meet future emission regulations' mandatory requirements for real-time remote transmission of vehicle NOx data. Summary of the Invention

[0004] This disclosure provides a method and apparatus for diagnosing engine aftertreatment efficiency, aiming to at least partially solve the technical problem of poor accuracy in diagnosing engine aftertreatment efficiency due to the lack of detection and consideration of the actual nitrogen oxide emission concentration in engine exhaust.

[0005] At least one embodiment of this disclosure provides a method for diagnosing engine aftertreatment efficiency, including:

[0006] Obtain the current actual state parameters of the vehicle that uses the engine as its power source; Based on the actual state parameters, determine whether the current operating condition of the vehicle meets the preset efficiency diagnosis triggering conditions. When the efficiency diagnosis trigger condition is met under the current operating conditions, a diagnostic parameter acquisition process matching the efficiency diagnosis trigger condition is initiated. This process generates diagnostic parameters related to the conversion efficiency of the three-way catalytic converter for nitrogen oxides in the engine aftertreatment system based on the pre-oxygen sensor data and nitrogen oxide sensor data from the actual state parameters. The pre-oxygen sensor is located at the input end of the three-way catalytic converter, and the nitrogen oxide sensor is located at the output end of the three-way catalytic converter. Initiate an after-treatment efficiency generation process that matches the efficiency diagnosis triggering conditions to generate engine after-treatment efficiency diagnosis results based on the diagnostic parameters.

[0007] The above solution offers the following technical advantages: It provides a method for diagnosing engine aftertreatment efficiency (TWC efficiency) and monitoring NOx emissions using a front oxygen sensor and a nitrogen oxide sensor. Compared to related technologies, this method effectively meets the requirement of the next stage of vehicle design specifications for installing nitrogen oxide sensors on heavy-duty spark-ignition engines by adding a nitrogen oxide sensor for direct monitoring of NOx emission concentration. Compared to related technologies that indirectly estimate aftertreatment efficiency, the nitrogen oxide sensor provides more accurate and real-time NOx concentration data, significantly improving the accuracy and response speed of emission control. Furthermore, this method applies the nitrogen oxide sensor data to the aftertreatment efficiency diagnosis process, more reliably determining whether the aftertreatment efficiency meets the standards, thus improving the reliability and real-time nature of the diagnosis results. In addition, this method eliminates the need for a rear oxygen sensor at the output of the three-way catalytic converter, thereby optimizing the sensing architecture while improving the accuracy of engine aftertreatment efficiency diagnosis, saving the hardware cost of a rear oxygen sensor, and correspondingly reducing the need for wiring harnesses and signal processing components, thereby reducing system complexity and overall manufacturing costs.

[0008] In at least one embodiment of the method provided in this disclosure, the efficiency diagnosis triggering condition includes: A first operating condition triggering condition associated with the process of resuming fuel supply after engine reversing is configured as follows: The engine aftertreatment temperature is higher than the preset first temperature. Fuel supply resumes after the vehicle enters the reverse towing condition for a period exceeding the preset first time but less than the preset second time. The fuel supply time after it is restored is longer than the preset third time.

[0009] The above solution has the following technical effects: Resuming fuel supply after towing is a typical operating condition, and the changes in nitrogen oxide sensor data are obvious. It can accurately assess the nitrogen oxide conversion efficiency of the three-way catalytic converter in dynamic scenarios, make up for the limitations of steady-state diagnosis, and improve the reliability of engine after-treatment efficiency diagnosis.

[0010] In at least one embodiment of the method provided in this disclosure, the diagnostic parameter acquisition process includes a first diagnostic parameter acquisition process matching a first operating condition triggering condition, the first diagnostic parameter acquisition process including: Determine whether the data from the front oxygen sensor reaches the set range corresponding to the standard air-fuel ratio used to characterize that the air-fuel mixture output by the engine is within the set range. When the pre-oxygen sensor data reaches the set range, monitoring of the nitrogen oxide sensor data is triggered; Acquire the first moment when the nitrogen oxide sensor data reaches a preset first set value and the second moment when the nitrogen oxide sensor data reaches a preset second set value; and, The time difference between the first time point and the second time point is obtained as the first diagnostic parameter.

[0011] The above solution has the following technical effects: it accurately obtains diagnostic parameters under the condition of resuming fuel supply after towing, and improves the reliability of engine after-treatment efficiency diagnosis.

[0012] In at least one embodiment of the method provided in this disclosure, the post-processing efficiency generation process includes a post-processing efficiency generation process matching a first operating condition triggering condition, wherein the post-processing efficiency generation process matching the first operating condition triggering condition includes: Obtain the average value of the first diagnostic parameter obtained N times in the current driving cycle, wherein the first diagnostic parameter is obtained N times in each driving cycle, and N≥1; In response to the average value of the first diagnostic parameter being greater than a time difference limit for characterizing the performance degradation of the three-way catalytic converter, a first diagnostic result is generated to characterize the current engine aftertreatment efficiency as normal; and, In response to the fact that the average value of the first diagnostic parameter is less than the time difference limit, a second diagnostic result is generated to characterize the current abnormality of the engine aftertreatment efficiency.

[0013] The above solution has the following technical effects: accurately determining whether the engine after-treatment efficiency is normal, and improving the reliability of engine after-treatment efficiency diagnosis.

[0014] In at least one embodiment of the method provided in this disclosure, the efficiency diagnosis triggering condition includes: A second operating condition triggering condition associated with the steady-state operation of the engine, the second operating condition triggering condition being configured as follows: The engine aftertreatment temperature is higher than the preset second temperature. The engine intake pressure is greater than the first set pressure, and The deviation of the engine intake pressure within the set time period shall not exceed the second set pressure.

[0015] The above solution has the following technical effects: the second operating condition triggering condition and the first operating condition triggering condition are used to start different after-treatment efficiency diagnostic schemes, which improves the reliability of engine after-treatment efficiency diagnosis.

[0016] In at least one embodiment of the method provided in this disclosure, the diagnostic parameter acquisition process includes a first diagnostic parameter acquisition process that matches the second operating condition triggering condition, and the second diagnostic parameter acquisition process includes: Determine whether the data from the front oxygen sensor reaches the set range corresponding to the standard air-fuel ratio used to characterize that the air-fuel mixture output by the engine is within the set range. When the pre-oxygen sensor data reaches the set range, the engine output power is obtained based on the engine speed and engine torque in the actual operating parameters, and the nitrogen oxide mass is obtained based on the nitrogen oxide sensor data and engine intake air flow in the actual operating parameters; and, The nitrogen oxide emissions per kilowatt-hour of work done by the engine are generated based on the nitrogen oxide mass emission rate and the engine output power, and used as a second diagnostic parameter.

[0017] The above solution has the following technical effects: it accurately obtains diagnostic parameters under steady-state engine operating conditions, and improves the reliability of engine after-treatment efficiency diagnosis.

[0018] In at least one embodiment of the method provided in this disclosure, the post-processing efficiency generation process includes a post-processing efficiency generation process matching a second operating condition triggering condition, wherein the post-processing efficiency generation process matching the second operating condition triggering condition includes: Obtain the second diagnostic parameters at multiple times within a second set time period; and, In response to the second diagnostic parameter exceeding the preset nitrogen oxide emission limit at every moment within at least 1 / 2 of the second set time period, a second diagnostic result is generated to characterize the current abnormality of engine aftertreatment efficiency.

[0019] The above solution has the following technical effects: accurately determining whether the engine after-treatment efficiency is normal, and improving the reliability of engine after-treatment efficiency diagnosis.

[0020] The method provided in at least one embodiment of this disclosure further includes: After the vehicle is powered on, the first working condition trigger condition is determined, and the first diagnostic parameter acquisition process and the corresponding post-processing efficiency generation process that match the first working condition trigger condition are executed to generate the first-level post-processing efficiency diagnostic result. In response to the first-level aftertreatment efficiency diagnostic result being a first diagnostic result characterizing the current engine aftertreatment efficiency as normal, the diagnosis of engine aftertreatment efficiency is terminated; and, In response to the first-level after-processing efficiency diagnosis result being a second diagnosis result used to characterize the current engine after-processing efficiency abnormality, the judgment of the second operating condition triggering condition and the second diagnosis parameter acquisition process and the corresponding after-processing efficiency generation process matching the second-level operating condition triggering condition are continued to be executed to generate the second-level after-processing efficiency diagnosis result, and the second diagnosis result is output only when the second-level after-processing efficiency diagnosis result is the second diagnosis result.

[0021] The above solution has the following technical effects: by using two-level operating condition diagnosis, the reliability of engine after-treatment efficiency diagnosis is improved.

[0022] In at least one embodiment of the method provided in this disclosure, the actual state parameters include engine speed, engine torque, engine aftertreatment temperature, engine intake pressure, engine intake flow rate, pre-oxygen sensor data, and nitrogen oxide sensor data; and... The method further includes: Before determining the trigger condition for the first operating condition, the engine aftertreatment efficiency is predicted based on data from the front and rear oxygen sensors, wherein the rear oxygen sensor is located at the output end of the three-way catalytic converter; and, In response to the determination that the engine after-treatment efficiency is abnormal based on the aforementioned prediction, the system executes the determination of the first operating condition trigger condition, the acquisition process of the first diagnostic parameter matching the first operating condition trigger condition, and the corresponding after-treatment efficiency generation process.

[0023] The above solution has the following technical effects: by using two-level operating condition diagnosis, the reliability of engine after-treatment efficiency diagnosis is improved.

[0024] At least one embodiment of this disclosure also provides an engine aftertreatment efficiency diagnostic device, comprising: A front oxygen sensor, located at the input end of the three-way catalytic converter in the engine aftertreatment system; A nitrogen oxide sensor, located at the input end of the three-way catalytic converter, and The controller is communicatively connected to the pre-oxygen sensor and the nitrogen oxide sensor; The controller includes: The acquisition unit is configured to acquire the current actual state parameters of the vehicle that uses the engine as a power source; The preprocessing unit is configured to determine whether the current operating condition of the vehicle meets the preset efficiency diagnosis triggering conditions based on the actual state parameters. A diagnostic parameter generation unit is configured to, when the current operating condition meets the efficiency diagnosis triggering condition, initiate a diagnostic parameter acquisition process matching the efficiency diagnosis triggering condition, to generate diagnostic parameters related to the conversion efficiency of the three-way catalytic converter to nitrogen oxides based on the pre-oxygen sensor data and nitrogen oxide sensor data in the actual state parameters; and, The result generation unit is configured to initiate an after-processing efficiency generation process that matches the efficiency diagnosis triggering conditions, in order to generate engine after-processing efficiency diagnosis results based on the diagnostic parameters.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of an example engine aftertreatment system; Figure 2 A flowchart of an engine aftertreatment efficiency diagnosis method provided for at least one embodiment of the present disclosure; Figure 3 A schematic diagram of a first diagnostic parameter acquisition process provided for at least one embodiment of this disclosure; Figure 4 A schematic diagram of NOx change curves after resuming fuel supply, provided for at least one embodiment of this disclosure; Figure 5 A flowchart illustrating an efficiency generation scheme based on a first diagnostic parameter, provided for at least one embodiment of this disclosure; Figure 6 A schematic diagram of a second diagnostic parameter acquisition process provided for at least one embodiment of this disclosure; Figure 7 A flowchart illustrating an efficiency generation scheme based on a second diagnostic parameter provided for at least one embodiment of this disclosure; Figure 8 A flowchart of an example of an engine aftertreatment efficiency diagnosis method provided in at least one embodiment of this disclosure; Figure 9 A flowchart of Example 2 of the engine aftertreatment efficiency diagnosis method provided in at least one embodiment of this disclosure; Figure 10 A flowchart of Example 3 of an engine aftertreatment efficiency diagnosis method provided in at least one embodiment of this disclosure; Figure 11 A structural block diagram of an engine aftertreatment efficiency diagnostic device provided in at least one embodiment of the present disclosure; Figure 12 A schematic diagram illustrating the composition of a program product provided for at least one embodiment of this disclosure.

[0028] Figure label: 1- Engine; 2- Engine controller; 3- First exhaust pipe; 4- Three-way catalytic converter; 5- Second exhaust pipe; 10- Engine aftertreatment efficiency diagnostic device; 11- Front oxygen sensor; 12- Nitrogen oxide sensor; 13- Controller; 131- Acquisition unit; 132- Preprocessing unit; 133- Diagnostic parameter generation unit; 134- Result generation unit; 21- Processor; 22- Memory; 23- Input device; 24- Output device; t1- First time point; t2- Second time point. Detailed Implementation

[0029] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the disclosure. Similarly, the following embodiments are only some, not all, embodiments of the present disclosure, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0030] The terms "first," "second," and "third" used in the embodiments of this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," and "third" may explicitly or implicitly include at least one of that feature.

[0031] In the description of this disclosure, "multiple" means at least two, such as two or three, unless otherwise expressly and specifically limited.

[0032] In this disclosure, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] The terms “comprising” and “having”, and any variations thereof, used in this disclosure are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0034] In the embodiments of this disclosure, the term "three-way catalytic converter," abbreviated as TWC, refers to an exhaust gas purification device installed in the engine aftertreatment system.

[0035] The term "nitrogen oxide sensor" in the embodiments of this disclosure is abbreviated as NOx sensor.

[0036] The term "engine aftertreatment efficiency" in the embodiments of this disclosure mainly refers to TWC efficiency in the following text.

[0037] In this disclosure, the term "engine controller" or ECU refers to the electronic control unit installed in the engine, which is the core control component for engine operation and after-treatment system.

[0038] The design concept of this disclosure will be explained first.

[0039] Figure 1 This is a schematic diagram illustrating the structure of an example engine aftertreatment system. Figure 1 As shown, the engine aftertreatment system may include engine 1, engine controller 2, first exhaust pipe 3 (also known as front exhaust pipe), three-way catalytic converter 4, and second exhaust pipe 5 (also known as rear exhaust pipe).

[0040] The engine's exhaust port is connected to the first exhaust pipe 3.

[0041] The input end of the three-way catalytic converter 4 is connected to the engine via the first exhaust pipe 3, and the output end of the three-way catalytic converter 4 is connected to a second exhaust pipe 5, which is different from the first exhaust pipe 3.

[0042] exist Figure 1 In the engine aftertreatment system, the first exhaust pipe 3, the three-way catalytic converter 4, and the second exhaust pipe 5 are arranged in series, and the engine controller 2 is installed on the engine 1.

[0043] exist Figure 1 Based on the engine aftertreatment system, the scheme disclosed herein adds a front oxygen sensor 11 and a nitrogen oxide sensor 12. The front oxygen sensor 11 is located in the first exhaust pipe 3 at the input end of the three-way catalytic converter 4, and the nitrogen oxide sensor 12 is located in the second exhaust pipe 5 at the output end of the three-way catalytic converter 4.

[0044] Compared to related technologies, the solution disclosed herein, by incorporating a nitrogen oxide sensor 12, enables real-time reading of nitrogen oxide sensor data, directly monitoring nitrogen oxide (NOx) emissions. Furthermore, it can directly diagnose engine aftertreatment efficiency based on data from the pre-oxygen sensor and the nitrogen oxide sensor (also known as the NOx signal), resulting in more accurate engine aftertreatment efficiency diagnostics. Moreover, the solution disclosed herein eliminates the need for a post-oxygen sensor, saving on the cost of a post-oxygen sensor while improving the accuracy of engine aftertreatment efficiency diagnostics.

[0045] Figure 2 This is a flowchart illustrating an engine aftertreatment efficiency diagnostic method provided in at least one embodiment of the present disclosure. The method can be applied to, but is not limited to, engine controllers; for example, it can also be applied to vehicle controllers. Figure 1 As shown, the method may include the following steps S10-S40.

[0046] Step S10: Obtain the current actual state parameters of the vehicle that uses the engine as a power source.

[0047] Step S20: Determine whether the current operating condition of the vehicle meets the preset efficiency diagnosis triggering conditions based on the actual state parameters.

[0048] Step S30: When the current operating condition meets the efficiency diagnosis trigger condition, start the diagnostic parameter acquisition process that matches the efficiency diagnosis trigger condition, so as to generate diagnostic parameters related to the conversion efficiency of nitrogen oxides by the three-way catalytic converter in the engine aftertreatment system based on the data of the front oxygen sensor and the nitrogen oxide sensor in the actual state parameters. The front oxygen sensor is located at the input end of the three-way catalytic converter, and the nitrogen oxide sensor is located at the output end of the three-way catalytic converter.

[0049] Step S40: Initiate the after-treatment efficiency generation process that matches the efficiency diagnosis trigger conditions to generate engine after-treatment efficiency diagnosis results based on diagnostic parameters.

[0050] It should be noted that the above scheme only has a nitrogen oxide sensor installed at the output end of the three-way catalytic converter, and no post-oxygen sensor.

[0051] Different efficiency diagnosis trigger conditions can be selected for different specified operating conditions, and each specified operating condition can correspond to one efficiency diagnosis trigger condition. If engine aftertreatment efficiency diagnosis is performed on only one specified operating condition in a driving cycle, there can be one efficiency diagnosis trigger condition. If engine aftertreatment efficiency diagnosis is performed on multiple specified operating conditions in a driving cycle, there can be multiple efficiency diagnosis trigger conditions. The efficiency diagnosis trigger condition for each specified operating condition may be matched with different diagnostic parameter acquisition procedures. The above scheme first determines whether the current operating condition is a suitable specified operating condition for engine aftertreatment efficiency diagnosis through steps S10-S20. If so, the diagnostic parameters matching the current operating condition are obtained through step S30 for the generation of the aftertreatment efficiency diagnosis result in step S40.

[0052] In the above scheme, this disclosure does not limit the actual state parameters of the vehicle in step S10. The actual state parameters are not a fixed combination. In practical application scenarios, in addition to the oxygen sensor data and nitrogen oxide sensor data mentioned later, the actual state parameters may also include engine speed, engine torque, engine aftertreatment temperature, engine intake pressure, engine intake flow rate, or other types of data. These parameters play a key auxiliary role in the diagnostic process: engine speed and engine torque can intuitively reflect the real-time load level of the engine and are one of the core bases for judging whether the current operating condition is in a stable operating range; engine aftertreatment temperature is directly related to the catalytic activity of the three-way catalytic converter. If the engine aftertreatment temperature does not reach the preset catalytic reaction threshold, even if the oxygen sensor data and nitrogen oxide sensor data are normal, the conversion efficiency may temporarily decrease; engine intake pressure and engine intake flow rate can help evaluate the control accuracy of the engine air-fuel ratio. The deviation of the air-fuel ratio will directly affect the original generation of pollutants such as nitrogen oxides, thereby interfering with the accurate calculation of the actual conversion efficiency of the three-way catalytic converter. In addition, depending on the configuration of the aftertreatment system and diagnostic requirements of different vehicle models, data such as fuel injection quantity, throttle opening, and exhaust back pressure can also be included in the scope of actual state parameter collection to achieve comprehensive coverage of diagnostic scenarios under complex working conditions, and further improve the accuracy and robustness of aftertreatment efficiency diagnostic results.

[0053] When the system executes step S10, it may need to select appropriate actual state parameters based on the specific actual working conditions to determine the efficiency diagnosis trigger conditions.

[0054] In the above scheme, this disclosure does not limit the efficiency diagnosis triggering conditions for step S20. The efficiency diagnosis triggering conditions may include the first operating condition triggering conditions described in later embodiments, or the second operating condition triggering conditions described in later embodiments, or a combination of the first and second operating condition triggering conditions. Besides the first and second operating condition triggering conditions, the efficiency diagnosis triggering conditions may also include triggering conditions where the engine's continuous stable running time meets a preset threshold, or triggering conditions where fuel quality adaptive adjustment is completed. The triggering condition where the engine's continuous stable running time meets a preset threshold aims to ensure that the operating conditions are in a long-term stable state, avoiding deviations in diagnostic results caused by instantaneous fluctuations. The triggering condition where fuel quality adaptive adjustment is completed takes into account that differences in fuel quality can change the original generation characteristics of pollutants; therefore, the diagnosis should only be initiated after the ECU completes adaptive calibration of fuel quality to ensure the reliability of the diagnostic results. These additional triggering conditions can be flexibly selected according to the vehicle's aftertreatment system configuration and actual diagnostic scenario requirements, further optimizing the diagnostic triggering timing and improving aftertreatment efficiency.

[0055] When the system executes step S20, it may need to select appropriate efficiency diagnosis trigger conditions according to the specific application scenario and actual needs, and identify the specified working conditions.

[0056] In the above scheme, this disclosure does not limit the diagnostic parameter acquisition process in step S30. In practical application scenarios, in addition to the schemes described in the following embodiments, key parameters such as temperature, pressure, flow rate, and pollutant concentration can be synchronously collected through multi-channel sensors based on the real-time status feedback of each core component of the aftertreatment system, and combined with historical operating data stored in the ECU for fusion calculation to obtain a more comprehensive set of diagnostic parameters. In addition, for scenarios with missing parameters under special operating conditions, necessary parameters can be supplemented by model prediction to ensure the continuity and accuracy of the diagnostic process. These flexible parameter acquisition methods can adapt to aftertreatment system architectures of different complexities, improving the versatility and robustness of the diagnostic methods.

[0057] When the system executes step S30, it can flexibly select a diagnostic parameter acquisition process that matches the efficiency diagnosis triggering conditions based on the complexity of the actual working conditions.

[0058] In the above scheme, this disclosure does not limit the post-processing efficiency generation process in step S40. In practical application scenarios, in addition to the schemes described in subsequent embodiments, a multi-dimensional evaluation model can also be constructed based on diagnostic parameters to comprehensively consider key dimensions such as emission conversion efficiency, performance degradation trend of core components, and operating condition adaptability, and output quantitative efficiency diagnostic results through weighted calculation or machine learning algorithms.

[0059] When the system executes step S40, it can flexibly select the appropriate post-processing efficiency generation process based on the complexity of the actual working conditions.

[0060] Steps S10-S40 provide a method for diagnosing engine aftertreatment efficiency (TWC efficiency) and monitoring NOx emissions using a front oxygen sensor and a nitrogen oxide sensor. Compared to related technologies, this method effectively meets the requirement of the next stage of vehicle design specifications for installing nitrogen oxide sensors on heavy-duty spark-ignition engines by adding a nitrogen oxide sensor for direct monitoring of NOx emission concentration. Compared to related technologies that indirectly estimate aftertreatment efficiency, the nitrogen oxide sensor can provide more accurate and real-time NOx concentration data, thereby significantly improving the accuracy and response speed of emission control. Simultaneously, this method applies the nitrogen oxide sensor data collected by the nitrogen oxide sensor to the aftertreatment efficiency diagnosis process, more reliably determining whether the aftertreatment efficiency meets the standards, improving the reliability and real-time nature of the aftertreatment efficiency diagnosis results. Furthermore, this method eliminates the need for a rear oxygen sensor at the output of the three-way catalytic converter, thus optimizing the sensing architecture while improving the accuracy of engine aftertreatment efficiency diagnosis, saving the hardware cost of a rear oxygen sensor, and correspondingly reducing the need for wiring harnesses and signal processing components, thereby reducing system complexity and overall manufacturing costs.

[0061] Some embodiments of this disclosure also provide apparatus, storage media, and program products corresponding to the methods described above.

[0062] The method provided in at least one embodiment of this disclosure is applicable to any existing engine aftertreatment system application scenario with a three-way catalytic converter. For example, the three-way catalytic converter aftertreatment system of a passenger car equipped with a conventional fuel injection system, or the three-way catalytic converter aftertreatment system of a high-performance vehicle using in-cylinder direct injection technology, can achieve efficient efficiency diagnosis through the method of this disclosure.

[0063] In some embodiments, Figure 2Based on the proposed solution, to further improve diagnostic reliability, step S10 acquires the vehicle's current actual status parameters, including engine speed, engine torque, engine aftertreatment temperature, engine intake pressure, engine intake flow rate, front oxygen sensor data, and nitrogen oxide sensor data. Engine speed and torque reflect the engine's real-time load level and are core indicators for judging operating stability. If fluctuations in either exceed preset thresholds, diagnostics must be paused to avoid misjudgments. Engine aftertreatment temperature directly affects the activity of the three-way catalytic converter and must be within the effective operating range of 250℃-800℃; otherwise, the diagnostic results will have significantly reduced reference value. Engine intake pressure and flow rate together determine the accuracy of the intake volume; deviations can lead to errors in fuel injection calculations, thus affecting the generation and conversion of emissions. Front oxygen sensor data monitors the oxygen concentration in the exhaust gas after combustion, helping to determine if the air-fuel ratio is within the ideal range. Nitrogen oxide sensor data directly reflects the three-way catalytic converter's conversion effect on nitrogen oxides and is one of the key bases for evaluating the efficiency of the aftertreatment system. These parameters need to be acquired in real-time via the vehicle's CAN bus and filtered to eliminate noise interference, ensuring the reliability of the input diagnostic results.

[0064] As an example implementation, after the vehicle key is powered on, step S10 can be executed to obtain the current actual status parameters of the vehicle, and the vehicle's operating status can be determined based on the actual status parameters.

[0065] The following describes the publicly available efficiency diagnosis triggering conditions, diagnostic parameter acquisition process, and post-processing efficiency generation process for the first operating condition.

[0066] In some embodiments, Figure 2 Based on the proposed solution, to further improve diagnostic reliability, the efficiency diagnostic triggering conditions include a first operating condition triggering condition associated with the process of resuming fuel supply after engine towing. This first operating condition triggering condition is configured as follows: the engine aftertreatment temperature is greater than a preset first temperature; the vehicle enters the towing condition for a period greater than a preset first time but less than a preset second time before resuming fuel supply; and the fuel supply time after resuming fuel supply is greater than a preset third time. The reason for setting this triggering condition is that resuming fuel supply after towing is a typical operating condition, with significant changes in NOx sensor data. This allows for accurate assessment of the three-way catalytic converter's NOx conversion efficiency under dynamic conditions, compensating for the limitations of steady-state diagnostics and improving the comprehensiveness and accuracy of aftertreatment efficiency diagnostics.

[0067] As an exemplary implementation, the first operating condition triggering condition is configured as follows: the engine after-treatment temperature is greater than 400°C, the vehicle enters the reverse towing condition for more than 5 seconds and less than 20 seconds before resuming fuel supply, and the fuel supply time is continuous and greater than 5 seconds.

[0068] Figure 3This is a schematic diagram of a first diagnostic parameter acquisition process provided for at least one embodiment of the present disclosure. Figure 2 Based on this, in order to further improve diagnostic reliability, the diagnostic parameter acquisition process in step S30 is configured to include a first diagnostic parameter acquisition process that matches the triggering condition of the first operating condition, wherein, for example... Figure 3 As shown, the first diagnostic parameter acquisition process includes the following sub-steps S301-S304.

[0069] Sub-step S301: Determine whether the data from the front oxygen sensor has reached the set range corresponding to the standard air-fuel ratio used to characterize the engine output mixture.

[0070] Sub-step S302: When the data from the pre-oxygen sensor reaches the set range, the monitoring of the nitrogen oxide sensor data is triggered.

[0071] Sub-step S303: Acquire the first moment when the nitrogen oxide sensor data reaches a preset first set value and the second moment when the nitrogen oxide sensor data reaches a preset second set value.

[0072] Sub-step S304: Obtain the time difference between the first time point and the second time point as the first diagnostic parameter.

[0073] It should be noted that both the first and second moments refer to the moments after the engine was retracted and fuel supply was restored. After fuel supply was restored, the NOx sensor data initially rose and then fell. The NOx change after fuel supply was restored is as follows: Figure 4 As shown, after fuel supply is restored, the gas content in the TWC is low, meaning the air-fuel ratio is biased towards air. Both the first and second setpoints are located a certain distance from the NOx peak value; they can be equal or unequal. Figure 4 Only the cases of equality are listed to determine the first time point t1 and the second time point t2.

[0074] The first setpoint is lower than the second setpoint, and both are calibrated based on the nitrogen oxide concentration variation pattern of the engine aftertreatment system under healthy operating conditions. The time difference can intuitively reflect the conversion response speed of nitrogen oxides in the catalyst. When the time difference is less than the preset time difference limit, it means that the catalyst's nitrogen oxide treatment efficiency may be reduced. This first diagnostic parameter will be used in conjunction with other subsequently acquired diagnostic parameters to jointly determine whether the aftertreatment system is working properly.

[0075] As an exemplary implementation, the air-fuel ratio is set to 1 ± 0.01.

[0076] Figure 5 A flowchart illustrating an efficiency generation scheme based on a first diagnostic parameter, provided for at least one embodiment of this disclosure. Figure 2 or Figure 3Based on the proposed solution, to further improve diagnostic reliability, the post-processing efficiency generation process in step S40 includes a post-processing efficiency generation process that matches the triggering conditions of the first operating condition, such as... Figure 5 As shown, when the current operating condition meets the first operating condition triggering condition in the diagnostic triggering conditions, step S40 further includes the following sub-steps S401-S403.

[0077] Sub-step S401: Obtain the average value of the first diagnostic parameters obtained N times in the current driving cycle, wherein the first diagnostic parameters are obtained N times in each driving cycle, and N≥1.

[0078] Sub-step S402: In response to the average value of the first diagnostic parameter being greater than the time difference limit used to characterize the performance degradation of the three-way catalytic converter, a first diagnostic result is generated to characterize the current engine aftertreatment efficiency as normal.

[0079] Sub-step S403: In response to the average value of the first diagnostic parameter being less than the time difference limit, a second diagnostic result is generated to characterize the current abnormality of the engine aftertreatment efficiency.

[0080] The value of N can be determined based on the calibration requirements of the engine aftertreatment system and actual operating conditions such as urban congestion or highway cruising. It is typically tested multiple times to balance diagnostic efficiency and accuracy. The time difference limit is a pre-calibrated critical value based on the nitrogen oxide conversion response characteristics of the three-way catalytic converter under healthy conditions, and needs to be individually adapted for different engine displacements, aftertreatment system models, and emission regulations. Simultaneously, after generating the diagnostic results, the ECU will output these results and report faults if the diagnostic results are abnormal (too low), facilitating rapid problem location by repair personnel.

[0081] In the above scheme, the time difference limit is related to various factors such as engine model and after-treatment capability, and can be calibrated through testing.

[0082] In some embodiments, Figure 5 Based on the scheme, in order to further improve the diagnostic accuracy, step S40 also includes the following sub-step S404.

[0083] Sub-step S404: Obtain the shortened time parameter based on the first diagnostic parameter obtained N times, and generate the engine after-treatment efficiency based on the shortened time parameter.

[0084] Among them, the first diagnostic parameter t2-t1 will be shortened after TWC deterioration, and the engine after-treatment efficiency can be quantified based on the shortening time parameter of the first diagnostic parameter t2-t1.

[0085] The following describes the publicly available efficiency diagnosis triggering conditions, diagnostic parameter acquisition process, and post-processing efficiency generation process for the second operating condition.

[0086] In some embodiments, Figure 2 Based on the existing scheme, to further improve diagnostic reliability, the efficiency diagnostic triggering condition in step S20 includes a second operating condition triggering condition associated with the engine's steady-state operation. This second operating condition triggering condition is configured as follows: the engine aftertreatment temperature is greater than a preset second temperature, the engine intake pressure is greater than a first set pressure, and the deviation of the engine intake pressure within a set time period does not exceed the second set pressure. The second operating condition triggering condition and the first operating condition triggering condition are used to activate different aftertreatment efficiency diagnostic schemes. The second temperature setting needs to be calibrated based on the ignition temperature characteristics of the three-way catalytic converter and the target emission regulations. It is usually set as the minimum temperature threshold to ensure that the three-way catalytic converter enters the high-efficiency conversion range, and this value can be calibrated between 350°C and 400°C. The first set pressure needs to match the intake pressure range under different engine loads to avoid triggering diagnostics under non-steady-state conditions such as low-load idling. It is generally set proportionally based on the intake pressure corresponding to the engine's rated power. The second set pressure is used to limit the fluctuation range of the intake pressure to ensure that the engine is under a stable load. For example, it can be set to within ±5% of the average intake pressure. The specific value needs to be verified and determined through bench testing combined with actual road conditions to balance the coverage and accuracy of the diagnostics.

[0087] As an exemplary implementation, the second operating condition triggering condition is configured as follows: the engine aftertreatment temperature is greater than 350°C, the engine intake pressure is greater than 150 kPa, and the deviation of the engine intake pressure within 5 seconds is within 20 kPa.

[0088] Figure 6 This is a schematic diagram of a second diagnostic parameter acquisition process provided for at least one embodiment of this disclosure. Figure 2 Based on the existing scheme, to further improve diagnostic reliability, the diagnostic parameter acquisition process in step S30 includes a second diagnostic parameter acquisition process that matches the triggering conditions of the second operating condition, such as... Figure 6 As shown, the process for obtaining the second diagnostic parameter includes the following sub-steps S305-S307.

[0089] Sub-step S305: Determine whether the data from the front oxygen sensor has reached the set range corresponding to the standard air-fuel ratio used to characterize the engine output mixture.

[0090] Sub-step S306: When the front oxygen sensor data reaches the set range, obtain the engine output power based on the engine speed and engine torque in the actual operating parameters, and obtain the nitrogen oxide mass based on the nitrogen oxide sensor data and engine intake air flow in the actual operating parameters.

[0091] Sub-step S307: Generate the amount of nitrogen oxide emissions corresponding to each kilowatt-hour of work done by the engine based on the nitrogen oxide mass emission rate and engine output power, and use it as the second diagnostic parameter.

[0092] It should be noted that sub-steps S305-S307 can be used independently when there are no sub-steps S301-S304, or they can be set after step S40.

[0093] The process begins with sub-steps S305-S307, which pre-verify the air-fuel ratio of the mixture to ensure that subsequent NOx emission data are based on stable engine combustion conditions, avoiding data distortion caused by deviations in the air-fuel ratio from the standard range. Building upon this, the correlation between engine output power and NOx mass is calculated to accurately capture the engine's NOx emission characteristics under specific operating conditions. The resulting NOx emission parameter per kilowatt-hour further eliminates interference from engine load variations in the diagnostic results, making the second diagnostic parameter more adaptable to different operating conditions and more comparable in data. This effectively improves the accuracy and reliability of engine aftertreatment efficiency diagnosis. This design not only ensures the scientific validity of the diagnostic parameters but also provides a more valuable quantitative indicator of whether the aftertreatment system is operating normally.

[0094] In the above scheme, the mass of nitrogen oxides in the gas mixture and the nitrogen oxide sensor data have the following fixed conversion relationship:

[0095] Where 277.78 is the unit conversion constant from kg / h to mg / s, 46 is the molar mass of NOx, 29 is the calibrated molar mass of exhaust gas, and the NOx volume concentration in the mixture is the nitrogen oxide sensor data.

[0096] Figure 7 A flowchart illustrating an efficiency generation scheme based on a second diagnostic parameter provided for at least one embodiment of this disclosure. Figure 6 Based on the proposed solution, to further improve diagnostic reliability, the post-processing efficiency generation process includes a post-processing efficiency generation process that matches the triggering conditions of the second operating condition, such as... Figure 7 As shown, when the current operating condition meets the second operating condition triggering condition in the diagnostic triggering conditions, step S40 further includes the following sub-steps S404-S405.

[0097] Sub-step S404: Obtain second diagnostic parameters at multiple times within a second set time period.

[0098] Sub-step S405: In response to the fact that the second diagnostic parameter exceeds the preset nitrogen oxide emission limit at every moment within at least 1 / 2 of the second set time period, a second diagnostic result is generated to characterize the current abnormality of engine aftertreatment efficiency.

[0099] It should be noted that sub-steps S404-S405 can be set after sub-steps S305-S307.

[0100] The second set time period can be calibrated according to the engine model, aftertreatment system type, and emission regulations. The nitrogen oxide specific emission limit is based on the baseline specific emission obtained from engine bench tests and dynamically adjusted in conjunction with correction factors such as ambient temperature and altitude. The sampling frequency for obtaining the second diagnostic parameters in sub-step S404 should be no less than 1Hz to ensure data continuity and representativeness. The judgment logic in sub-step S405 aims to filter out interference from instantaneous operating condition fluctuations and ensure the stability of the diagnostic results. Only when all sampling point parameters exceed the limit for more than half the duration of the continuous monitoring period are the aftertreatment efficiency deemed abnormal, thereby effectively reducing the possibility of misdiagnosis.

[0101] As an example implementation, the first limit is 5 mg / kWh, but the limit may vary depending on the engine displacement.

[0102] In some embodiments, Figures 2-7 In order to further improve diagnostic reliability, based on any of the schemes, the method also includes the following steps S01-S03.

[0103] Step S01: After the vehicle is powered on, the process of determining the first operating condition trigger condition and obtaining the first diagnostic parameter matching the first operating condition trigger condition is executed. Figure 3 Neutron steps S301-S304) and the corresponding post-processing efficiency generation process ( Figure 5 Neutron step S401-sub-step S403) to generate the first-level post-processing efficiency diagnosis results.

[0104] Step S02: In response to the first-level after-treatment efficiency diagnosis result being a first diagnostic result used to characterize the current engine after-treatment efficiency as normal, the diagnosis of engine after-treatment efficiency is terminated.

[0105] Step S03: In response to the first-level aftertreatment efficiency diagnosis result being a second diagnostic result characterizing the current engine aftertreatment efficiency anomaly, continue executing the judgment of the second operating condition triggering condition and the second diagnostic parameter acquisition process matching the second-level operating condition triggering condition. Figure 6 Neutron step S305-sub-step S307) and corresponding post-processing efficiency generation process ( Figure 7(Neutron step S404-sub-step S405) to generate the second-level post-processing efficiency diagnosis result, and output the second diagnosis result only when the second-level post-processing efficiency diagnosis result is also the second diagnosis result.

[0106] The division of the two-level operating condition triggering conditions follows a diagnostic strategy of starting with the simple and progressing to the complex, and prioritizing speed over accuracy. This ensures diagnostic efficiency under normal conditions and reduces the false alarm rate of abnormal diagnosis through a dual verification mechanism, thus ensuring the reliability of the output diagnostic results.

[0107] In some embodiments, Figures 2-7 In order to further improve diagnostic reliability, based on any of the schemes, the method further includes the following steps S01'-S02'.

[0108] Step S01': Before determining the first operating condition triggering condition, the engine after-treatment efficiency is predicted based on the data from the front oxygen sensor and the rear oxygen sensor, wherein the rear oxygen sensor is located at the output end of the three-way catalytic converter.

[0109] Step S02': In response to the pre-determined abnormality of engine after-treatment efficiency, the first operating condition trigger condition is determined, and the first diagnostic parameter acquisition process and the corresponding after-treatment efficiency generation process are executed.

[0110] It should be noted that this disclosure does not restrict the order of the post-oxygen sensor and the nitrogen oxide sensor.

[0111] This predictive step utilizes the real-time data differences between the front and rear oxygen sensors for rapid analysis, enabling preliminary judgment without waiting for specific operating conditions to trigger. This effectively filters out most scenarios where the after-processing efficiency is clearly normal, thereby reducing the number of subsequent first-condition trigger judgments and diagnostic processes, and lowering the computational load on the ECU. Furthermore, it only proceeds to the more precise diagnostic stage when the predictive result is abnormal, further complementing the dual verification mechanism of the two-level diagnosis, and jointly improving the accuracy of diagnostic results and system operating efficiency.

[0112] Figure 8 A flowchart illustrating an example of an engine aftertreatment efficiency diagnostic method provided in at least one embodiment of this disclosure. Figure 8 As shown, the method includes: 1) After detecting that the vehicle key is powered on, the ECU obtains the actual status parameters of the vehicle; 2) Determine if the vehicle has reached the first operating condition. The first operating condition is when the engine after-treatment temperature is greater than 400℃. The vehicle enters the reverse towing condition for more than 5 seconds but less than 20 seconds and then resumes fuel supply. The fuel supply time must be continuously greater than 5 seconds. 3) When the vehicle reaches the first operating condition, the engine after-treatment efficiency is calculated. The calculation is performed 3 times in one driving cycle. The calculation is terminated when the engine after-treatment efficiency meets the termination condition, and the final result of the engine after-treatment efficiency is obtained. The termination condition is that t2-t1 obtained from the first calculation is <3s or the average value of the 3 calculation results is obtained. The engine after-treatment efficiency calculation process is as follows: Under the first operating condition, if the measured value of the front oxygen sensor reaches the set range, the first time t1 when the nitrogen oxide sensor data reaches the first set value and the second time t2 when the data reaches the second set value are recorded. If the average value of the 3 t2-t1 calculation results is < the time difference limit, the engine after-treatment efficiency is determined to be low. The set range is air-fuel ratio 1 ± 0.01.

[0113] Figure 9 A flowchart illustrating Example 2 of an engine aftertreatment efficiency diagnostic method provided in at least one embodiment of this disclosure. Figure 9 As shown, the method includes: 1) After detecting that the vehicle key is powered on, the ECU obtains the actual status parameters of the vehicle; 2) Determine whether the vehicle is operating in the second operating condition. The second operating condition is when the engine after-treatment temperature is greater than 350℃, the engine intake pressure is greater than 150kPa, and the deviation of the engine intake pressure within 20kPa within 5 seconds. 3) When the vehicle enters the second operating condition, the NOx emission mass calculation begins. The second operating condition must be maintained for at least 6 seconds. If the steady-state condition is exited in the middle, the next determination will start from re-entering the second operating condition. The calculation is performed once per driving cycle. The NOx emission mass calculation process is as follows: The vehicle controller ECU obtains the data from the front oxygen sensor. If the data from the front oxygen sensor is within the preset range, the engine speed and engine torque are obtained, and the engine output power (also known as the engine's work per second) is calculated. The NOx emission mass is obtained from the NOx sensor data and the engine intake air flow. The NOx emission mass in mg / kwh is calculated by combining the NOx emission mass and the engine output power. If the NOx emission mass is greater than the nitrogen oxide emission limit for 3 seconds within 6 seconds, the engine after-treatment efficiency is judged to be low.

[0114] Among these parameters, the air-fuel ratio is 1 ± 0.01 when the pre-oxygen sensor data is within the preset range. The nitrogen oxide emission limit is 5 mg / kWh, but this limit may vary depending on the engine displacement. NOx emission mass is calculated every second, which reduces the impact of sudden sensor fluctuations. A fault is considered to occur only if the emission exceeds the limit for 3 out of 6 seconds.

[0115] Figure 8 and Figure 9 The two methods for diagnosing engine aftertreatment efficiency can be used individually or in combination. When used in combination, first... Figure 8 The method is used to judge. If the diagnostic result shows that the engine aftertreatment efficiency is normal, the next step of judgment is terminated; if the calculation result shows that the engine aftertreatment efficiency is too low (abnormal), then... Figure 9 The method was used for verification. Figure 9 The method verification result also shows that the engine after-treatment efficiency is too low, so it is determined that the engine after-treatment efficiency is too low. Figure 9 If the verification result shows that the engine after-treatment efficiency is normal, then the process of obtaining vehicle status information is repeated, and the procedure is followed accordingly. Figure 8 Methods Figure 9 The method involves calculating steps until the engine aftertreatment efficiency diagnosis is completed.

[0116] Figure 10 A flowchart of Example 3 of an engine aftertreatment efficiency diagnosis method provided in at least one embodiment of this disclosure. Figure 9 As shown, NOx sensor monitoring and post-oxygen sensor monitoring are cross-verified to improve monitoring reliability. Specifically, after testing the oxygen storage capacity using both sensors, if an abnormal engine aftertreatment efficiency (low engine aftertreatment efficiency) is detected (i.e., the engine aftertreatment efficiency is below a set threshold), a fault is detected by... Figure 8 The method is used to reconfirm the engine after-treatment efficiency; if the relevant technical solution results in normal engine after-treatment efficiency, then this driving cycle will obtain a normal efficiency result.

[0117] Figure 11 This is a structural block diagram of an engine aftertreatment efficiency diagnostic device provided in at least one embodiment of the present disclosure. Figure 11 As shown, the engine aftertreatment efficiency diagnostic device 10 includes a front oxygen sensor 11, a nitrogen oxide sensor 12, and a controller 13.

[0118] The front oxygen sensor 11 is located at the input end of the three-way catalytic converter in the engine aftertreatment system.

[0119] The nitrogen oxide sensor 12 is located at the input end of the three-way catalytic converter.

[0120] The controller 13 is communicatively connected to the pre-oxygen sensor 11 and the nitrogen oxide sensor 12.

[0121] The controller includes an acquisition unit 131, a preprocessing unit 132, a diagnostic parameter generation unit 133, and a result generation unit 134.

[0122] Acquisition unit 131 is configured to acquire the current actual state parameters of a vehicle that uses an engine as a power source.

[0123] The preprocessing unit 132 is configured to determine whether the current operating condition of the vehicle meets the preset efficiency diagnosis triggering conditions based on the actual state parameters.

[0124] The diagnostic parameter generation unit 133 is configured to initiate a diagnostic parameter acquisition process that matches the efficiency diagnosis triggering conditions when the current operating condition meets the conditions, so as to generate diagnostic parameters related to the conversion efficiency of the three-way catalytic converter to nitrogen oxides based on the pre-oxygen sensor data and nitrogen oxide sensor data in the actual state parameters.

[0125] The result generation unit 134 is configured to initiate an after-processing efficiency generation process that matches the efficiency diagnosis trigger conditions, so as to generate engine after-processing efficiency diagnosis results based on diagnostic parameters.

[0126] The specific execution methods of each unit in the above system embodiments have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0127] In some embodiments, Figure 11 Based on this, the acquisition unit 131 can be implemented through a corresponding receiving module, and the preprocessing unit 132, the diagnostic parameter generation unit 133, and the result generation unit 134 can be implemented through a controller or control module with corresponding programs.

[0128] This disclosure also provides a storage medium storing a program or instructions that, when executed by a processor, implement the steps of the method embodiments described above.

[0129] This disclosure also provides a program product, such as... Figure 12 As shown, the program product includes one or more processors 21 and memory 22. Figure 12 Take a processor 21 as an example.

[0130] The controller may also include an input device 23 and an output device 24.

[0131] The processor 21, memory 22, input device 23, and output device 24 can be connected via a bus or other means. Figure 12 Taking the example of a connection between China and Israel via a bus.

[0132] The processor 21 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips. The general-purpose processor can be a microprocessor or any conventional processor.

[0133] The memory 22, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 21 executes various functional applications and data processing of the server by running the non-transitory software programs, instructions, and modules stored in the memory 22, thereby implementing the steps of the above-described method embodiments.

[0134] The memory 22 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the use of the processing device operated by the server. Furthermore, the memory 22 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 22 may optionally include memory remotely located relative to the processor 21, and these remote memories may be connected to a network connection device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0135] Input device 23 can receive input digital or character information, and generate key signal inputs related to driver settings and function control of the server's processing unit. Output device 24 may include display devices such as a display screen.

[0136] One or more modules are stored in memory 22, and when executed by one or more processors 21, they perform actions such as... Figure 1 The method shown.

[0137] Those skilled in the art will understand that all or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory (FM), hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0138] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.

[0139] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A method for diagnosing engine aftertreatment efficiency, characterized in that, include: Obtain the current actual state parameters of the vehicle that uses the engine as its power source; Based on the actual state parameters, determine whether the current operating condition of the vehicle meets the preset efficiency diagnosis trigger condition. When the efficiency diagnosis trigger condition is met under the current operating conditions, a diagnostic parameter acquisition process matching the efficiency diagnosis trigger condition is initiated. This process generates diagnostic parameters related to the conversion efficiency of the three-way catalytic converter for nitrogen oxides in the engine aftertreatment system based on the pre-oxygen sensor data and nitrogen oxide sensor data from the actual state parameters. The pre-oxygen sensor is located at the input end of the three-way catalytic converter, and the nitrogen oxide sensor is located at the output end of the three-way catalytic converter. Initiate an after-treatment efficiency generation process that matches the efficiency diagnosis triggering conditions to generate engine after-treatment efficiency diagnosis results based on the diagnostic parameters.

2. The method according to claim 1, characterized in that, The efficiency diagnosis trigger conditions include: A first operating condition triggering condition associated with the process of resuming fuel supply after engine reversing is configured as follows: The engine aftertreatment temperature is higher than the preset first temperature. Fuel supply resumes after the vehicle enters the reverse towing condition for a period exceeding the preset first time but less than the preset second time. The fuel supply time after it is restored is longer than the preset third time.

3. The method according to claim 1 or 2, characterized in that, The diagnostic parameter acquisition process includes a first diagnostic parameter acquisition process that matches the first operating condition triggering condition, and the first diagnostic parameter acquisition process includes: Determine whether the data from the front oxygen sensor reaches the set range corresponding to the standard air-fuel ratio used to characterize that the air-fuel mixture output by the engine is within the set range. When the pre-oxygen sensor data reaches the set range, monitoring of the nitrogen oxide sensor data is triggered; Acquire the first moment when the nitrogen oxide sensor data reaches a preset first set value and the second moment when the nitrogen oxide sensor data reaches a preset second set value; and, The time difference between the first time point and the second time point is obtained as the first diagnostic parameter.

4. The method according to claim 1 or 2, characterized in that, The post-processing efficiency generation process includes a post-processing efficiency generation process that matches the first operating condition triggering condition, and the post-processing efficiency generation process that matches the first operating condition triggering condition includes: Obtain the average value of the first diagnostic parameter obtained N times in the current driving cycle, wherein the first diagnostic parameter is obtained N times in each driving cycle, and N≥1; In response to the average value of the first diagnostic parameter being greater than a time difference limit for characterizing the performance degradation of the three-way catalytic converter, a first diagnostic result is generated to characterize the current engine aftertreatment efficiency as normal; and, In response to the fact that the average value of the first diagnostic parameter is less than the time difference limit, a second diagnostic result is generated to characterize the current abnormality of the engine aftertreatment efficiency.

5. The method according to claim 1 or 2, characterized in that, The efficiency diagnosis trigger conditions include: A second operating condition triggering condition associated with the steady-state operation of the engine, the second operating condition triggering condition being configured as follows: The engine aftertreatment temperature is higher than the preset second temperature. The engine intake pressure is greater than the first set pressure, and The deviation of the engine intake pressure within the set time period shall not exceed the second set pressure.

6. The method according to claim 1 or 2, characterized in that, The diagnostic parameter acquisition process includes a first diagnostic parameter acquisition process that matches the second operating condition triggering condition, and the second diagnostic parameter acquisition process includes: Determine whether the data from the front oxygen sensor reaches the set range corresponding to the standard air-fuel ratio used to characterize that the air-fuel mixture output by the engine is within the set range. When the pre-oxygen sensor data reaches the set range, the engine output power is obtained based on the engine speed and engine torque in the actual operating parameters, and the nitrogen oxide mass is obtained based on the nitrogen oxide sensor data and engine intake air flow in the actual operating parameters; and, The nitrogen oxide emissions per kilowatt-hour of work done by the engine are generated based on the nitrogen oxide mass emission rate and the engine output power, and used as a second diagnostic parameter.

7. The method according to claim 1 or 2, characterized in that, The post-processing efficiency generation process includes a post-processing efficiency generation process that matches the second operating condition triggering condition, and the post-processing efficiency generation process that matches the second operating condition triggering condition includes: Obtain the second diagnostic parameters at multiple times within a second set time period; and, In response to the second diagnostic parameter exceeding the preset nitrogen oxide emission limit at every moment within at least 1 / 2 of the second set time period, a second diagnostic result is generated to characterize the current abnormality of engine aftertreatment efficiency.

8. The method according to claim 1 or 2, characterized in that, Also includes: After the vehicle is powered on, the first working condition trigger condition is determined, and the first diagnostic parameter acquisition process and the corresponding post-processing efficiency generation process that match the first working condition trigger condition are executed to generate the first-level post-processing efficiency diagnostic result. In response to the first-level after-treatment efficiency diagnosis result being a first diagnostic result used to characterize the current engine after-treatment efficiency as normal, the diagnosis of engine after-treatment efficiency is terminated. as well as, In response to the first-level after-processing efficiency diagnosis result being a second diagnosis result used to characterize the current engine after-processing efficiency abnormality, the judgment of the second operating condition triggering condition and the second diagnosis parameter acquisition process and the corresponding after-processing efficiency generation process matching the second-level operating condition triggering condition are continued to be executed to generate the second-level after-processing efficiency diagnosis result, and the second diagnosis result is output only when the second-level after-processing efficiency diagnosis result is the second diagnosis result.

9. The method according to claim 2, characterized in that, The actual state parameters include engine speed, engine torque, engine aftertreatment temperature, engine intake pressure, engine intake flow, front oxygen sensor data, and nitrogen oxide sensor data. and, The method further includes: Before determining the trigger condition for the first operating condition, the engine aftertreatment efficiency is predicted based on data from the front and rear oxygen sensors, wherein the rear oxygen sensor is located at the output end of the three-way catalytic converter; and, In response to the determination that the engine after-treatment efficiency is abnormal based on the aforementioned prediction, the system executes the determination of the first operating condition trigger condition, the acquisition process of the first diagnostic parameter matching the first operating condition trigger condition, and the corresponding after-treatment efficiency generation process.

10. An engine aftertreatment efficiency diagnostic device, characterized in that, include: A front oxygen sensor, located at the input end of the three-way catalytic converter in the engine aftertreatment system; A nitrogen oxide sensor, wherein the nitrogen oxide sensor is located at the output end of the three-way catalytic converter, and The controller is communicatively connected to the pre-oxygen sensor and the nitrogen oxide sensor; The controller includes: The acquisition unit is configured to acquire the current actual state parameters of the vehicle that uses the engine as a power source; The preprocessing unit is configured to determine whether the current operating condition of the vehicle meets the preset efficiency diagnosis triggering conditions based on the actual state parameters. A diagnostic parameter generation unit is configured to, when the efficiency diagnosis triggering condition is met under the current operating condition, initiate a diagnostic parameter acquisition process matching the efficiency diagnosis triggering condition, to generate diagnostic parameters related to the conversion efficiency of the three-way catalytic converter to nitrogen oxides based on the pre-oxygen sensor data and nitrogen oxide sensor data in the actual state parameters; and, The result generation unit is configured to initiate an after-processing efficiency generation process that matches the efficiency diagnosis triggering conditions, in order to generate engine after-processing efficiency diagnosis results based on the diagnostic parameters.

Images