Three-way catalyst fault diagnosis method and device and electronic equipment

Abstract

The invention relates to the technical field of engines, and provides a three-way catalyst fault diagnosis method and device and electronic equipment. Comprising the steps of entering a fault diagnosis mode under the condition that a fault diagnosis condition is met; the air-fuel ratio is adjusted, and signal changes of the front oxygen sensor and the rear oxygen sensor are monitored; based on the signal change, acquiring an oxygen storage amount measurement parameter; calculating a three-way catalyst performance monitoring index based on the oxygen storage amount measurement parameter; and if the three-way catalyst performance monitoring index is not lower than the preset diagnosis threshold value, it is determined that the three-way catalyst is normal. Fault diagnosis can be carried out on the three-way catalytic converter, so that whether the purification performance of the three-way catalytic converter meets the requirement or not can be judged, and emission performance control of an engine is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a method, a device and an electronic device for diagnosing a three-way catalytic converter fault. Background Art

[0002] With the upgrading of automobile emission regulations, the requirements for emission pollutants are becoming more and more stringent. As the most effective post-treatment device for gasoline vehicles today, the three-way catalytic converter can reduce pollutants in gasoline engine exhaust and is widely used in traditional fuel vehicles and hybrid vehicles. The three-way catalytic converter can reduce the emission of three pollutants (nitrogen oxides, carbon monoxide and hydrocarbons) at the same time. The three-way catalytic converter uses a carrier as a matrix. By coating the three-way catalytic active coating on the inner wall of the carrier, a redox reaction occurs with the exhaust pollutants, thereby achieving the purification function of the engine exhaust.

[0003] As the vehicle is used for a longer time, the three-way catalytic converter will fail due to abnormal operation of the engine management system, poor and irregular operating conditions, and poor vehicle maintenance, which will affect the purification performance of the three-way catalytic converter.

[0004] Therefore, an effective diagnostic strategy to determine whether the purification performance of the three-way catalytic converter meets the requirements is of great significance to the emission performance control of the engine. Summary of the invention

[0005] In view of this, the embodiments of the present application provide a three-way catalytic converter fault diagnosis method, device and electronic device, which can diagnose the fault of the three-way catalytic converter, so as to determine whether the purification performance of the three-way catalytic converter meets the requirements, which is beneficial to the emission performance control of the engine.

[0006] A first aspect of an embodiment of the present application provides a three-way catalytic converter fault diagnosis method, comprising:

[0007] When the fault diagnosis conditions are met, enter the fault diagnosis mode;

[0008] Adjust the air-fuel ratio and monitor the signal changes of the front and rear oxygen sensors;

[0009] Based on the signal change, obtaining oxygen storage measurement parameters;

[0010] Calculating a three-way catalytic converter performance monitoring index based on the oxygen storage measurement parameter;

[0011] If the three-way catalytic converter performance monitoring index is not lower than a preset diagnosis threshold, it is determined that the three-way catalytic converter is normal.

[0012] A second aspect of an embodiment of the present application provides a three-way catalytic converter fault diagnosis device, comprising:

[0013] A diagnosis condition judgment module is used to enter a fault diagnosis mode when the fault diagnosis conditions are met;

[0014] The regulating module is used to adjust the air-fuel ratio and monitor the signal changes of the front and rear oxygen sensors;

[0015] A measurement parameter acquisition module, used to acquire oxygen storage measurement parameters based on the signal change;

[0016] A calculation module, used for calculating a three-way catalytic converter performance monitoring index based on the oxygen storage measurement parameter;

[0017] The fault diagnosis module is used to determine that the three-way catalytic converter is normal if the three-way catalytic converter performance monitoring index is not lower than a preset diagnosis threshold.

[0018] A third aspect of an embodiment of the present application provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the electronic device implements the three-way catalytic converter fault diagnosis method provided in the first aspect of the embodiment of the present application.

[0019] A fourth aspect of the embodiments of the present application provides a computer program product, including a computer program. When the computer program is executed, the method according to the first aspect of the embodiments of the present application is executed.

[0020] The three-way catalytic converter fault diagnosis method provided in the first aspect of the embodiment of the present application enters the fault diagnosis mode after meeting specific diagnostic conditions, and accurately adjusts the air-fuel ratio to monitor the changes in the front and rear oxygen sensor signals, thereby obtaining the oxygen storage measurement parameters. The three-way catalytic converter performance monitoring index calculated based on these parameters can accurately evaluate the working state of the catalyst. If the index is not lower than the preset diagnostic threshold, it is confirmed that the catalyst performance is normal. It combines the dynamic adjustment of the air-fuel ratio and the real-time monitoring of the sensor signal changes to ensure the high accuracy and reliability of the three-way catalytic converter performance evaluation. At the same time, by setting a clear diagnostic threshold, the accuracy of fault diagnosis is improved, effectively ensuring the stable operation and environmental performance of the vehicle emission system.

[0021] It can be understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a flow chart of a three-way catalytic converter fault diagnosis method provided in one embodiment of the present application;

[0024] Figure 2 is a schematic diagram of the structure of a three-way catalytic converter fault diagnosis device provided in an embodiment of the present application;

[0025] Figure 3 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0027] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0028] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0029] The three-way catalytic converter fault diagnosis method provided in the embodiment of the present application can be executed by the processor of the electronic device when running a computer program with corresponding functions, by entering the fault diagnosis mode after meeting specific diagnostic conditions, and accurately adjusting the air-fuel ratio to monitor the changes in the front and rear oxygen sensor signals, thereby obtaining the oxygen storage measurement parameters. The three-way catalytic converter performance monitoring index calculated based on these parameters can accurately evaluate the working state of the catalyst. If the index is not lower than the preset diagnostic threshold, it is confirmed that the catalyst performance is normal. The advantage of this method is that it combines the dynamic adjustment of the air-fuel ratio and the real-time monitoring of the sensor signal changes, ensuring the high accuracy and reliability of the three-way catalytic converter performance evaluation, while improving the accuracy of fault diagnosis by setting a clear diagnostic threshold, effectively ensuring the stable operation and environmental performance of the vehicle emission system.

[0030] like Figure 1 As shown, the three-way catalytic converter fault diagnosis method provided in the embodiment of the present application includes the following steps S101 to S105:

[0031] Step S101: Entering a fault diagnosis mode when a fault diagnosis condition is met.

[0032] Step S102: adjust the air-fuel ratio and monitor the signal changes of the front and rear oxygen sensors.

[0033] In application, the ECU (electronic control unit) can be used to accurately control the fuel injection amount and intake volume, change the air-fuel ratio, and thus affect the exhaust composition, achieving the effect of actively adjusting the air-fuel ratio (A / F).

[0034] In the application, the output data of the front and rear oxygen sensors are monitored in real time. The output of the oxygen sensor can be a voltage signal or a digital signal, reflecting the change of oxygen concentration in the exhaust gas. Among them, the front oxygen sensor (upstream) is located before the catalyst and is mainly used for feedback control of the air-fuel ratio; the rear oxygen sensor (downstream) is located after the catalyst and is used to evaluate the working efficiency of the catalyst.

[0035] Step S103: Obtain oxygen storage measurement parameters based on the signal change.

[0036] In the application, based on the changes in the oxygen sensor signal, record the key time points and time intervals, such as the starting time point t of measuring the oxygen storage capacity. start and the duration t of measuring oxygen storage meas .

[0037] Step S104: Calculate the three-way catalytic converter performance monitoring index based on the oxygen storage measurement parameter.

[0038] Step S105: If the three-way catalytic converter performance monitoring index is not lower than the preset diagnosis threshold, it is determined that the three-way catalytic converter is normal.

[0039] In the application, if the performance monitoring index of the three-way catalytic converter is lower than the preset diagnostic threshold, the driver will be reminded to perform maintenance in time in the failure mode to ensure the safe and normal operation of the vehicle. The fault diagnosis and positioning is accurate and timely, which improves the driving reliability of the vehicle.

[0040] In one embodiment, adjusting the air-fuel ratio and monitoring the signal changes of the front and rear oxygen sensors include:

[0041] enriching the mixture to reduce the air-fuel ratio to a first preset concentration, and monitoring changes in concentration data output by the front and rear oxygen sensors;

[0042] The mixture is diluted to increase the air-fuel ratio to a second preset concentration, and changes in the concentration data output by the front and rear oxygen sensors are monitored.

[0043] In application, the oxygen content in the exhaust gas can be reduced by increasing the amount of fuel injection, thereby reducing the air-fuel ratio. At this time, the output signals of the front and rear oxygen sensors will gradually decrease, indicating that the mixture has become richer. The oxygen content in the exhaust gas can be increased by reducing the amount of fuel injection, thereby increasing the air-fuel ratio. At this time, the output signals of the front and rear oxygen sensors will gradually increase, indicating that the mixture has become thinner.

[0044] The embodiment of the present application precisely controls the change in the air-fuel ratio so that the output data of the front and rear oxygen sensors can accurately reflect the change in the oxygen concentration in the exhaust gas, thereby providing a reliable data basis for the measurement of oxygen storage capacity, comprehensively testing the oxygen storage and release capacity of the three-way catalytic converter under different operating conditions, and ensuring the comprehensiveness and accuracy of the diagnostic results.

[0045] In one embodiment, the oxygen storage measurement parameters include the starting time point t of measuring the oxygen storage start and the duration t of measuring oxygen storage meas ;

[0046] Based on the signal changes, oxygen storage measurement parameters are obtained, including:

[0047] In the process of enriching the mixture to reduce the air-fuel ratio to the first preset concentration, if the concentration output by the front and rear oxygen sensors is greater than the corresponding enrichment threshold, the current time point is used as the starting time point t for measuring the oxygen storage amount. start ;

[0048] In the process of diluting the mixture and increasing the air-fuel ratio to the second preset concentration, if the concentration output by the front and rear oxygen sensors is less than the corresponding dilution threshold, the starting time point t start The time interval between the current time point and the measured oxygen storage time t meas .

[0049] In application, in actual operation, when the system needs to perform enrichment operation, the fuel injection pulse width can be increased through the ECU to reduce the air-fuel ratio to about 13.7. At this time, the output signals of the front and rear oxygen sensors will gradually change from low level or low voltage (indicating a lean state) to high level or high voltage (indicating a rich state). After these signals of the front and rear oxygen sensors are higher than their respective set enrichment thresholds, the current time point is recorded as the starting time point t for measuring the oxygen storage amount. start . Then, the ECU reduces the fuel injection pulse width, so that the air-fuel ratio rises to about 15.7. At this time, the output signals of the front and rear oxygen sensors will gradually change from high level or high voltage to low level or low voltage. After these signals of the front and rear oxygen sensors are lower than their respective set lean thresholds, the current time point is recorded and t is subtracted. start , calculate the duration t of measuring oxygen storage meas .

[0050] In the application, the starting time t start It refers to the time point when the system starts to record the change of oxygen storage capacity, which usually occurs during the enrichment stage when the oxygen sensor signal is stably higher than the enrichment threshold. meas It refers to the time interval from the starting time point to the end of the lean mixture stage, reflecting the speed at which the three-way catalytic converter releases stored oxygen and participates in the chemical reaction. Assuming that the system is in the stage of enriching the mixture, the output signals of the current and rear oxygen sensors are higher than the set enrichment threshold (for example, the narrow oxygen sensor, the enrichment threshold is about 145AD), the system records the current time as t start ; Then, in the stage of reducing the mixture, when the output signal of the current and rear oxygen sensors is lower than the set reduction threshold again (for example, the narrow oxygen sensor, the reduction threshold is about 30AD), the system records the current time and calculates t meas This time difference reflects the oxygen release capacity and reaction rate of the catalyst, ensuring the accurate acquisition of the oxygen storage measurement parameters. Based on these parameters, the oxygen storage capacity and reaction rate of the three-way catalytic converter can be evaluated more scientifically, the reliability of fault diagnosis can be improved, unnecessary long-term measurement can be avoided, and the diagnostic efficiency can be improved.

[0051] In one embodiment, the formula for calculating the three-way catalyst performance monitoring index OSC (Oxygen Storage Capacity) is:

[0052]

[0053] Where a is the mass fraction of oxygen in the air; The differential of the exhaust mass flow rate discharged from the engine into the catalyst; sensor is the target value of the air-fuel ratio in the cylinder; t start is the starting time point for measuring oxygen storage; t measThe duration of oxygen storage is measured.

[0054] In one embodiment, when a fault diagnosis condition is met, entering a fault diagnosis mode includes:

[0055] If the catalyst diagnostic calibration enable is turned on;

[0056] The engine is in a hot state and in normal working condition;

[0057] The engine is in normal working condition;

[0058] And the catalyst is in optimal performance;

[0059] The engine is in idling and stable working condition;

[0060] If there is no fault that prohibits diagnosis, the fault diagnosis mode is entered.

[0061] In the application, confirm that the catalyst diagnostic function has been enabled to ensure that subsequent diagnosis can be carried out normally. When all diagnostic conditions are met, add the catalyst diagnostic enable condition completion flag. When the diagnostic conditions are met and the flag is set, the catalyst performance diagnostic function is turned on.

[0062] In the embodiment of the present application, when all diagnostic conditions are met, the three-way catalytic converter performance diagnosis function is enabled only after all diagnostic enable flags are set, thereby reducing the risk of false alarms. In addition, the fault diagnosis conditions are comprehensively considered, thereby improving the accuracy of fault diagnosis and saving the cost of fault diagnosis. Therefore, the present invention has a high accuracy of fault diagnosis and a low cost of fault diagnosis.

[0063] In one embodiment, it further includes:

[0064] If the engine running time is within the calibrated engine running time range;

[0065] And the coolant temperature is within the calibrated coolant temperature range;

[0066] If the engine speed is within the calibrated speed range, it is determined that the engine is in a hot state.

[0067] In one embodiment, it further includes:

[0068] If the ambient temperature is within the calibrated ambient temperature range;

[0069] And the atmospheric pressure is within the calibrated atmospheric pressure range;

[0070] If the fuel learning value integral item is within the calibrated fuel learning value integral item range, it is determined that the engine is in a normal working state.

[0071] In one embodiment, it further includes:

[0072] If the catalyst temperature is within the calibrated catalyst temperature range, it is determined that the catalyst is in an optimal performance state.

[0073] In one embodiment, it further includes:

[0074] If the engine flow is within the calibrated engine flow range and the vehicle speed is within the calibrated vehicle speed threshold, it is determined that the engine is in an idle and stable operating condition.

[0075] In the application, the fault diagnosis conditions are as follows:

[0076]

[0077]

[0078] In application, the above ranges can be calibrated. When determining the specific conditions for the engine to be in a hot state, the engine running time is within the calibrated engine running time range, such as at least 400s; the coolant temperature is within the calibrated coolant temperature range, such as 70°C to 110°C; the engine speed is within the calibrated speed range, such as 700rpm to 1000rpm; the engine running time ensures that the engine has been running long enough to reach a stable operating temperature; the coolant temperature reflects the actual temperature inside the engine, ensuring that the engine is in a hot state.

[0079] In the application, when determining the specific conditions for the engine to be in normal working condition, the ambient temperature is within the calibrated ambient temperature range, such as -7°C to 100°C; the atmospheric pressure is within the calibrated atmospheric pressure range, such as greater than 73kPa; the fuel learning value integral item is within the calibrated fuel learning value integral item range, ensuring the accuracy of the fuel injection system; these conditions ensure that the external environment will not have a significant impact on the engine performance, the appropriate vehicle speed range ensures that the vehicle is in a stable driving state, avoids the impact of sudden acceleration or deceleration on the diagnostic results, ensures the long-term stability of the fuel injection system, and avoids the impact of inaccurate fuel injection on the diagnostic results.

[0080] In the application, when determining the specific conditions of the engine being in an idle and stable operating state, it is necessary to determine that the engine flow is within the calibrated engine flow range, such as 400 mg / s to 1500 mg / s; the vehicle speed is within the calibrated vehicle speed threshold, such as when the vehicle is stopped and idling, the vehicle speed is 0.

[0081] In application, when determining the specific conditions for the catalyst to be in the best performance state, the catalyst temperature is within the calibrated catalyst temperature range, such as 450°C to 850°C; the catalyst temperature directly affects the working efficiency of its internal active materials, and ensuring that the temperature is within the effective range can ensure the best performance of the catalyst; suppose that after the vehicle has been driving for a period of time, the system checks and finds that the catalyst temperature is 600°C; in this case, the system confirms that the catalyst is in the best performance state and is ready for the next step of diagnosis. This method ensures that the catalyst is in an efficient working state and ensures the accuracy of the diagnostic results.

[0082] In one embodiment, after calculating the three-way catalyst performance monitoring index OSC, the calculated value is also corrected, including different corrections to oxygen storage capacity due to different catalyst temperatures and different corrections to oxygen storage capacity due to different air flows.

[0083] In one embodiment, after calculating the three-way catalytic converter performance monitoring index OSC, a filter coefficient k is added to filter the result of calculating the oxygen storage capacity OSC, and the filtered OSC is compared with a preset diagnostic threshold to determine the Pass / Fail result.

[0084] In the application, the filtering algorithm introduces a filtering coefficient k to smooth the original OSC data, reduce the impact of noise and instantaneous fluctuations, and thus improve the reliability of the diagnostic results. Specifically, after the oxygen storage capacity OSC is calculated based on the changes in the front and rear oxygen sensor signals, a filtering step is introduced to ensure the accuracy of the diagnostic results and avoid misjudgments due to sensor noise or other instantaneous factors. The filtering coefficient k is a value between 0 and 1, which determines the weight distribution between the new measurement value and the historical average. For example, if k = 0.8, the currently measured OSC value only accounts for 80% of the final filtering result, while 20% comes from the previously accumulated historical data. This weighted average method helps to filter out short-term fluctuations and retain long-term trends, making the diagnosis more stable and reliable. Next, the filtered OSC value will be evaluated.

[0085] In one embodiment, the preset diagnosis threshold is obtained by summing up and calculating the OSC of the limit catalyst and the OSC of the aged catalyst after testing.

[0086] In the application, the preset diagnostic threshold is calculated by testing the OSC (Oxygen Storage Capacity) of the limit catalyst (i.e., the catalyst whose performance has dropped to the critical point, such as the catalyst after driving 160,000 km), the OSC of the aged catalyst (i.e., the catalyst whose performance has slightly dropped after a period of use), and the OSC of the catalyst in the ideal performance state (i.e., the fresh catalyst). In order to ensure that this threshold can accurately reflect the actual working condition of the three-way catalytic converter and can maintain consistency under different vehicles and operating conditions, the following method can be used to achieve it.

[0087] In the application, a batch of new, unused three-way catalysts (i.e., fresh catalysts) can be selected as samples, which represent several common models and technical specifications on the market. In a controlled environment, each sample is subjected to a series of rigorous tests to determine its maximum oxygen storage capacity under optimal conditions. This includes simulating various operating conditions, such as different temperatures, air-fuel ratios, and exhaust flow rates, to obtain a series of OSC data points. By performing statistical analysis on these data points, the average OSC value of the fresh catalyst and its distribution characteristics can be obtained.

[0088] At the same time, in order to evaluate the aging effect of the catalyst, several catalysts that have undergone long-term actual road driving or accelerated aging tests were selected as a comparison group. Accelerated aging tests usually simulate extreme working environments, such as high temperatures, frequent hot and cold cycles, and high-load operation, in order to quickly reproduce the physical and chemical changes that occur in the catalyst over time. For each extreme catalyst and aged catalyst, the above test process is also repeated throughout its service life, and the corresponding OSC data is recorded.

[0089] After completing the collection of the above three sets of OSC data, they are combined for comprehensive analysis. Considering the potential differences between the two, cluster analysis or principal component analysis in machine learning algorithms can be used to identify key patterns and extract useful information.

[0090] Finally, based on all the above research results, a reasonable diagnostic threshold is preset. This threshold is designed to distinguish between catalysts in normal working conditions and those that may have problems. For example, if the OSC value measured on a vehicle's three-way catalytic converter is significantly lower than this threshold, it indicates that it may have aged or been damaged to a certain extent, which in turn affects the vehicle's overall emission performance. At this point, maintenance personnel can take further measures based on the diagnostic prompts, such as checking for blockage, replacing damaged parts, or adjusting engine control system parameters, to ensure that the vehicle always meets environmental standards.

[0091] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0092] The embodiment of the present application also provides a three-way catalytic converter fault diagnosis device, which is used to perform the steps in the above three-way catalytic converter fault diagnosis method embodiment. The three-way catalytic converter fault diagnosis device can be a virtual appliance in an electronic device, which is run by a processor of the electronic device, or it can be the electronic device itself. The electronic device can be an ECU, etc.

[0093] like Figure 2 As shown, the three-way catalytic converter fault diagnosis device 100 provided in the embodiment of the present application includes:

[0094] The diagnosis condition judgment module 101 is used to enter the fault diagnosis mode when the fault diagnosis condition is met;

[0095] The regulating module 102 is used to adjust the air-fuel ratio and monitor the signal changes of the front and rear oxygen sensors;

[0096] A measurement parameter acquisition module 103, used to acquire oxygen storage measurement parameters based on signal changes;

[0097] A calculation module 104, used for calculating a three-way catalytic converter performance monitoring index based on the oxygen storage measurement parameter;

[0098] The fault diagnosis module 105 is configured to determine that the three-way catalytic converter is normal if the three-way catalytic converter performance monitoring index is not lower than a preset diagnosis threshold.

[0099] In application, each module in the three-way catalytic converter fault diagnosis device may be a software program module, or may be implemented by different logic circuits integrated in a processor, or may be implemented by multiple distributed processors.

[0100] like Figure 3 As shown, the embodiment of the present application further provides an electronic device 200, including: at least one processor 201 ( Figure 3 Only one processor is shown in the figure), a memory 202, and a computer program 203 stored in the memory 202 and executable on at least one processor 201, wherein the processor 201 implements the steps in the above-mentioned various method embodiments when executing the computer program 203.

[0101] In applications, electronic devices may include, but are not limited to, processors and memories. Those skilled in the art will appreciate that Figure 3The electronic device is merely an example and does not limit the electronic device, and may include more or less components than those shown in the figure, or may combine certain components, or may include different components.

[0102] In applications, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0103] In application, the memory may be an internal storage unit of an electronic device in some embodiments, such as a hard disk or memory of the electronic device. The memory may also be an external storage device of the electronic device in other embodiments, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Further, the memory may also include both an internal storage unit of the electronic device and an external storage device. The memory is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as program code of a computer program, etc. The memory may also be used to temporarily store data that has been output or is to be output.

[0104] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0105] The embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0106] An embodiment of the present application provides a computer program product, including a computer program. When the computer program product runs on an electronic device, the electronic device can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0107] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A three-way catalytic converter fault diagnosis method, characterized in that: include: When the fault diagnosis conditions are met, enter the fault diagnosis mode; Adjust the air-fuel ratio and monitor the signal changes of the front and rear oxygen sensors; Based on the signal change, obtaining oxygen storage measurement parameters; Calculating a three-way catalytic converter performance monitoring index based on the oxygen storage measurement parameter; If the three-way catalytic converter performance monitoring index is not lower than a preset diagnosis threshold, it is determined that the three-way catalytic converter is normal.

2. The three-way catalytic converter fault diagnosis method according to claim 1, characterized in that: The air-fuel ratio is adjusted and the signal changes of the front and rear oxygen sensors are monitored, including: enriching the mixture to reduce the air-fuel ratio to a first preset concentration, and monitoring changes in concentration data output by the front and rear oxygen sensors; The mixture is diluted to increase the air-fuel ratio to a second preset concentration, and changes in the concentration data output by the front and rear oxygen sensors are monitored.

3. The three-way catalytic converter fault diagnosis method according to claim 2, characterized in that: The oxygen storage measurement parameters include the starting time point t of measuring the oxygen storage start and the duration t of measuring oxygen storage meas ; The obtaining of oxygen storage measurement parameters based on the signal change includes: In the process of enriching the mixture to reduce the air-fuel ratio to the first preset concentration, if the concentration output by the front and rear oxygen sensors is greater than the corresponding enrichment threshold, the current time point is used as the starting time point t for measuring the oxygen storage amount. start ; In the process of diluting the mixture to increase the air-fuel ratio to the second preset concentration, if the concentrations output by the front and rear oxygen sensors are both less than their respective corresponding dilution thresholds, the starting time point t start The time interval between the current time point and the measured oxygen storage time t meas .

4. The three-way catalytic converter fault diagnosis method according to claim 1, characterized in that: The formula for calculating the three-way catalytic converter performance monitoring index is: Where a is the mass fraction of oxygen in the air; The differential of the exhaust mass flow rate discharged from the engine into the catalyst; sensor is the target value of the air-fuel ratio in the cylinder; t start is the starting time point for measuring oxygen storage; t meas The duration of oxygen storage is measured.

5. The three-way catalytic converter fault diagnosis method according to claim 1, characterized in that: When the fault diagnosis condition is met, entering the fault diagnosis mode includes: If the catalyst diagnostic calibration enable is turned on; The engine is in a hot state; The engine is in normal working condition; And the catalyst is in optimal performance; The engine is in idling and stable working condition; If there is no fault that prohibits diagnosis, the fault diagnosis mode is entered.

6. The three-way catalytic converter fault diagnosis method according to claim 5, characterized in that: Also includes: If the engine running time is within the calibrated engine running time range; And the coolant temperature is within the calibrated coolant temperature range; If the engine speed is within the calibrated speed range, it is determined that the engine is in a hot state.

7. The three-way catalytic converter fault diagnosis method according to claim 5, characterized in that: Also includes: If the ambient temperature is within the calibrated ambient temperature range; And the atmospheric pressure is within the calibrated atmospheric pressure range; If the fuel learning value integral item is within the calibrated fuel learning value integral item range, it is determined that the engine is in a normal working state.

8. The three-way catalytic converter fault diagnosis method according to claim 5, characterized in that: Also includes: If the catalyst temperature is within the calibrated catalyst temperature range, it is determined that the catalyst is in an optimal performance state; If the engine flow is within the calibrated engine flow range and the vehicle speed is within the calibrated vehicle speed threshold, it is determined that the engine is in an idle and stable operating condition.

9. A three-way catalytic converter fault diagnosis device, characterized in that: include: A diagnosis condition judgment module is used to enter a fault diagnosis mode when the fault diagnosis conditions are met; The regulating module is used to adjust the air-fuel ratio and monitor the signal changes of the front and rear oxygen sensors; A measurement parameter acquisition module, used to acquire oxygen storage measurement parameters based on the signal change; A calculation module, used for calculating a three-way catalytic converter performance monitoring index based on the oxygen storage measurement parameter; The fault diagnosis module is used to determine that the three-way catalytic converter is normal if the three-way catalytic converter performance monitoring index is not lower than a preset diagnosis threshold.

10. An electronic device, characterized in that: The electronic device comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the electronic device implements the method as claimed in any one of claims 1 to 8.

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