Fault detection method and device of front oxygen sensor, storage medium and electronic equipment

Abstract

The application provides a kind of front oxygen sensor fault detection method and device, storage medium and electronic equipment, belong to engine field, this method includes: based on injection quantity control signal control the injection quantity of injector, then if confirming that engine is in stable operation state, start periodic detection;In each cycle, excess air coefficient is predicted, and the predicted signal of excess air coefficient is obtained;Obtain the measured signal of excess air coefficient;According to the predicted signal, judge whether the current cycle is valid, if valid, then according to the measured signal, determine the sensor detection result of current cycle;If the current cycle does not meet the detection termination condition, then enter the next cycle, if it meets the condition, then end the periodic detection process, determine the fault detection result according to all sensor detection results.The method of the application can realize effective fault detection of diagnosis state through injection quantity control, and determine the final result through repeated detection, which can avoid false alarm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engines, in particular to a front oxygen sensor fault detection method and device, a storage medium and an electronic device. BACKGROUND

[0002] In the operation process of a natural gas engine, the control system needs to measure the excess air ratio of the engine based on the front oxygen sensor, and adjust the fuel injection amount based on the measured value of the excess air ratio to realize oxygen closed-loop control of the engine.

[0003] The non-response fault is one of the common faults of the front oxygen sensor, and the non-response fault refers to the fact that the sensor is stuck and the sensor signal remains unchanged. When the front oxygen sensor has a non-response fault, the measured excess air ratio will no longer change with the change in fuel injection amount. In order to ensure the accuracy of the measurement of the excess air ratio, it is usually necessary to detect whether the front oxygen sensor has a non-response fault.

[0004] At present, the detection method for the non-response fault of the front oxygen sensor mainly monitors the change rate of the excess air ratio measured by the front oxygen sensor, and when the change rate is lower than a preset change rate threshold, it is determined that the front oxygen sensor has a non-response fault.

[0005] However, in real operation scenarios, the excess air ratio measured by the front oxygen sensor may also be in a relatively stable state under some non-fault conditions, for example, after the sensor ages, weak changes in the injection amount will no longer cause the measured value of the front oxygen sensor to change, and for example, under some special working conditions, the measured value of the front oxygen sensor remains unchanged. When the existing method is used to detect the fault of the front oxygen sensor, if the change rate of the excess air ratio is lower than the change rate threshold due to non-fault reasons, it will also be determined that the front oxygen sensor has a non-response fault, resulting in false positives, which reduces the accuracy of fault detection and easily causes adverse effects on the operation of the engine. SUMMARY

[0006] Therefore, the embodiments of the present application provide a front oxygen sensor fault detection method to solve the problem that the existing detection method for the non-response fault of the front oxygen sensor easily causes false positives in scenarios where the change rate of the excess air ratio is low due to non-fault reasons, which reduces the accuracy of fault detection.

[0007] The embodiments of the present application also provide a front oxygen sensor fault detection device to ensure the implementation and application of the above method in practice.

[0008] To achieve the above object, the embodiments of the present application provide the following technical solutions:

[0009] A front oxygen sensor fault detection method comprises:

[0010] generate an injection amount control signal when it is necessary to perform fault detection on the front oxygen sensor; the injection amount control signal is a square wave signal, and the amplitude of the square wave signal represents an injection amount;

[0011] perform injection amount control on the injection of the engine in a detection state based on the injection amount control signal, and determine whether the engine is in a stable operating state after the injection amount control is performed;

[0012] if the engine is in a stable operating state, periodically detect the front oxygen sensor;

[0013] perform excess air coefficient prediction processing on the front oxygen sensor in a current detection period to obtain an excess air coefficient prediction signal corresponding to the current detection period;

[0014] obtain an excess air coefficient measured signal based on the excess air coefficient measured by the front oxygen sensor in the current detection period;

[0015] determine whether the current detection period is a valid detection period according to the excess air coefficient prediction signal;

[0016] if the current detection period is a valid detection period, determine a sensor detection result of the current detection period according to the excess air coefficient measured signal; the sensor detection result represents whether the front oxygen sensor has a non-response fault;

[0017] determine whether the current detection period meets a preset detection termination condition, if the current detection period does not meet the detection termination condition, enter a next detection period, and if the current detection period meets the detection termination condition, end the periodic detection process of the front oxygen sensor;

[0018] after the periodic detection process of the front oxygen sensor is ended, determine a fault detection result of the front oxygen sensor according to the obtained sensor detection results.

[0019] The above method can optionally include:

[0020] obtaining a current original injection amount control signal, an actual speed of the engine, and an actual exhaust flow rate;

[0021] determining a signal amplitude and a signal frequency according to the actual speed and the actual exhaust flow rate;

[0022] constructing an initial square wave signal based on the signal amplitude and the signal frequency;

[0023] The original injection amount control signal and the initial square wave signal are superimposed, and the superimposed signal is used as the injection amount control signal.

[0024] Optionally, the method further includes:

[0025] determining an air amount signal and a fuel gas amount signal corresponding to the current detection period, wherein the air amount signal represents an air amount flowing through the engine mixer, and the fuel gas amount signal represents a fuel gas amount flowing through the engine injection valve;

[0026] respectively performing signal delay processing on the air amount signal and the fuel gas amount signal to obtain a first delay signal corresponding to the air amount signal and a second delay signal corresponding to the fuel gas amount signal;

[0027] determining an actual air-fuel ratio signal based on the first delay signal and the second delay signal;

[0028] determining an equivalent air-fuel ratio signal corresponding to the current detection period;

[0029] calculating a predicted value of the excess air coefficient in real time according to the actual air-fuel ratio signal and the equivalent air-fuel ratio signal, and composing the excess air coefficient prediction signal by the predicted value of the excess air coefficient calculated in real time.

[0030] Optionally, the method further includes:

[0031] obtaining a maximum value of the predicted value of the excess air coefficient and a minimum value of the predicted value of the excess air coefficient from the excess air coefficient prediction signal;

[0032] calculating a first range, wherein the first range is a difference between the maximum value of the predicted value of the excess air coefficient and the minimum value of the predicted value of the excess air coefficient;

[0033] determining whether the first range is greater than a preset first range threshold;

[0034] if the first range is greater than the first range threshold, determining that the current detection period is a valid detection period.

[0035] Optionally, the method further includes:

[0036] acquiring a maximum value of the excess air coefficient measured value from the excess air coefficient measured signal, and acquiring a minimum value of the excess air coefficient measured value;

[0037] calculating a second range; the second range is a difference between the maximum value of the excess air coefficient measured value and the minimum value of the excess air coefficient measured value;

[0038] judging whether the second range is greater than a preset second range threshold value;

[0039] if the second range is greater than the second range threshold value, regarding a conclusion that the front oxygen sensor does not exist a non-response fault as a sensor detection result corresponding to the current detection period.

[0040] The above method, optionally, the judgment whether the current detection period meets a preset detection termination condition comprises:

[0041] determining a current effective detection period number;

[0042] judging whether the effective detection period number reaches a preset period number threshold value;

[0043] if the effective detection period number has reached the period number threshold value, determining that the current detection period meets the detection termination condition.

[0044] The above method, optionally, the determination of the fault detection result of the front oxygen sensor according to the obtained sensor detection results comprises:

[0045] determining a total number of effective detection periods;

[0046] counting the number of sensor detection results representing that the front oxygen sensor does not exist a non-response fault to obtain a non-fault result number;

[0047] calculating a ratio of the non-fault result number to the total number of effective detection periods, and judging whether the ratio is less than a preset ratio threshold value;

[0048] if the ratio is less than the ratio threshold value, regarding a conclusion that the front oxygen sensor exists a non-response fault as the fault detection result.

[0049] A fault detection device of a front oxygen sensor comprises:

[0050] a signal generation unit configured to generate an injection amount control signal when it is necessary to detect a fault of the front oxygen sensor; the injection amount control signal is a square wave signal, and an amplitude of the square wave signal represents an injection amount;

[0051] an injection control unit, configured to perform injection quantity control on an injector of the engine in a detection state based on the injection quantity control signal, and to determine whether the engine is in a stable operating state after performing the injection quantity control;

[0052] a periodic detection unit, configured to perform periodic detection on the front oxygen sensor if the engine is in a stable operating state;

[0053] A coefficient prediction unit, configured to perform excess air coefficient prediction processing on the front oxygen sensor in a current detection cycle to obtain an excess air coefficient prediction signal corresponding to the current detection cycle;

[0054] A coefficient measurement unit, configured to obtain an excess air coefficient actual measurement signal measured by the front oxygen sensor during the current detection cycle;

[0055] a first judging unit, configured to judge whether the current detection cycle is a valid detection cycle according to the excess air coefficient prediction signal;

[0056] a first determining unit configured to determine, if the current detection cycle is a valid detection cycle, a sensor detection result of the current detection cycle based on the excess air coefficient measured signal; the sensor detection result indicating whether the front oxygen sensor has an unresponsive fault;

[0057] a second determining unit, configured to determine whether the current detection cycle meets a preset detection termination condition, and if so, to proceed to a next detection cycle; and if so, to terminate the periodic detection process of the front oxygen sensor;

[0058] The second determining unit is configured to determine a fault detection result of the front oxygen sensor according to the obtained detection results of each sensor after the periodic detection process of the front oxygen sensor is completed.

[0059] A storage medium includes stored instructions, wherein when the instructions are executed, the device where the storage medium is located is controlled to execute the above-mentioned method for detecting a fault of a front oxygen sensor.

[0060] An electronic device includes a memory and one or more instructions, wherein the one or more instructions are stored in the memory and configured to be executed by one or more processors to implement the above-mentioned method for detecting a fault in a front oxygen sensor.

[0061] The method for detecting the failure of the front oxygen sensor provided by the embodiment of the application comprises: generating a fuel injection amount control signal when it is necessary to detect the failure of the front oxygen sensor; the fuel injection amount control signal is a square wave signal, and the amplitude of the square wave signal represents the fuel injection amount; performing fuel injection amount control on the fuel injector of the engine based on the fuel injection amount control signal, and determining whether the engine is in a stable operation state after the fuel injection amount control is performed; if the engine is in the stable operation state, periodically detecting the front oxygen sensor; in the current detection period, performing excess air coefficient prediction processing on the front oxygen sensor to obtain an excess air coefficient prediction signal corresponding to the current detection period; obtaining an excess air coefficient actual measurement signal measured based on the front oxygen sensor in the current detection period; determining whether the current detection period is a valid detection period according to the excess air coefficient prediction signal; if the current detection period is the valid detection period, determining a sensor detection result of the current detection period according to the excess air coefficient actual measurement signal; the sensor detection result represents whether the front oxygen sensor has a non-response failure; determining whether the current detection period meets a preset detection termination condition, if the current detection period does not meet the detection termination condition, entering a next detection period, if the current detection period meets the detection termination condition, ending the periodic detection process of the front oxygen sensor; and determining a failure detection result of the front oxygen sensor according to the obtained sensor detection results when the periodic detection process of the front oxygen sensor is ended. When the non-response failure of the front oxygen sensor is detected by using the method provided by the embodiment of the application, the fuel injector of the engine is controlled according to the generated fuel injection amount control signal, the fuel injector sprays fuel based on the fuel injection amount control signal, the front oxygen sensor enters a state in which the theoretical measurement value should change accordingly, the front oxygen sensor is periodically detected in the spraying state, the predicted excess air coefficient is used to identify whether effective detection can be performed in the current state, the failure of the front oxygen sensor is detected based on the excess air coefficient measured by the front oxygen sensor when the effective detection can be performed, and therefore the effectiveness of the detection result of each period is ensured. By actively controlling the fuel injection amount and judging the effectiveness of the detection state, the scene in which the measurement value changes slightly due to various non-failure reasons can be effectively excluded, the excess air coefficient measured by the front oxygen sensor can be accurately detected at this time, the false alarm of the failure can be avoided, the accuracy of the failure detection is improved, and the stable operation of the engine is ensured. In addition, the final failure detection result is determined by combining a large number of diagnosis results through periodic repeated detection, and the accuracy of the failure detection can be further improved. BRIEF DESCRIPTION OF DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative effort based on the provided drawings.

[0063] Figure 1 A method flow chart of a fault detection method of a front oxygen sensor provided by an embodiment of the present application;

[0064] Figure 2 A variation diagram of injection amount and excess air coefficient in an ideal state provided by an embodiment of the present application;

[0065] Figure 3 A schematic diagram of a fault detection process of a front oxygen sensor provided by an embodiment of the present application;

[0066] Figure 4 A structural schematic diagram of a fault detection device of a front oxygen sensor provided by an embodiment of the present application;

[0067] Figure 5 A structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0068] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the present application.

[0069] In the present application, the term “comprising” or “including” or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitation, the element defined by the sentence “including a…” does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0070] An embodiment of the present application provides a fault detection method of a front oxygen sensor. The method can be applied to a fault detection system, and an execution subject of the method can be an electronic control unit (ECU) of a vehicle. A method flow chart of the method is shown in Figure 1 The method includes the following steps.

[0071] S101: generating an injection amount control signal when it is necessary to perform fault detection on the front oxygen sensor; the injection amount control signal is a square wave signal, and the amplitude of the square wave signal represents the injection amount;

[0072] In the method provided by the embodiment of the application, during the operation of the natural gas engine, it can be monitored in real time whether the working condition meets the triggering condition of fault diagnosis, so as to monitor whether it is necessary to perform fault detection on the front oxygen sensor. The working condition that can be applied specifically can include whether the engine speed and load meet the requirements of fault diagnosis, whether the oxygen sensor has passed the dew point detection, and the like, for example, the engine speed and load meeting the requirements and the oxygen sensor having passed the dew point detection can be taken as the triggering condition of fault diagnosis.

[0073] When it is necessary to perform fault detection on the front oxygen sensor, the processor can generate a signal for controlling the injection amount of the fuel injector of the engine based on a predetermined control strategy, and the signal specifically represents the set value of the injection amount. Specifically, the original control signal for the injection amount, that is, the original set value of the injection amount, can be converted into a square wave signal corresponding to a frequency and an amplitude by superimposing a square wave on the original control signal for the injection amount, and the square wave signal can be taken as the current injection amount control signal.

[0074] S102: performing injection amount control on the injector of the engine in a detection state based on the injection amount control signal, and judging whether the engine is in a stable operation state after the injection amount control is performed;

[0075] In the method provided by the embodiment of the application, the processor can send the injection amount control signal to the control unit of the injector to perform injection amount control on the injector in a detection state, that is, in a normal state, the set value of the injection amount determined according to the working condition is used to control the injection amount of the injector by the corresponding control unit of the injector, and after entering the fault detection state, the processor needs to trigger the control unit of the injector to control the injection amount of the injector according to the injection amount change indicated by the injection amount control signal. After the injection amount control on the injector is performed, it is necessary to monitor whether the engine is in a stable operation state.

[0076] The judgment condition of whether the engine is in a stable running state can be set according to actual needs, for example, whether the engine is in a stable running state can be judged based on the change of the working condition, the oxygen closed loop correction coefficient, the value range of the excess air coefficient measured by the front oxygen sensor and the like. Specifically, whether the change rate of the engine speed is lower than the preset speed change rate threshold, whether the change rate of the manifold pressure is lower than the preset pressure change rate threshold, whether the change rate of the oxygen closed loop correction coefficient is lower than the preset coefficient change rate threshold, and whether the value of the excess air coefficient measured by the front oxygen sensor is within a reasonable range can be judged, and when the above conditions are all met and last for a certain time, it can be considered that the engine is in a stable running state.

[0077] S103: if the engine is in a stable running state, periodically detecting the front oxygen sensor;

[0078] In the method provided by the embodiment of the application, if the engine is in a stable running state, the detection period can be set according to the preset periodic detection strategy, the length of the detection period is set, and the front oxygen sensor is periodically detected according to the length of the detection period, and then the detection process of the first detection period is entered. In each detection period, the set detection operation is completed. Specifically, the length of the detection period can be set according to needs. For example, the frequency of the injection amount control signal can be used to calculate the corresponding period, and the length of the period is used as the length of the detection period, so as to set the detection period.

[0079] In the method provided by the embodiment of the application, if the engine is not in a stable running state, it is considered that the current fault detection is not suitable, and the current fault detection process is ended.

[0080] S104: in the current detection period, performing excess air coefficient prediction processing on the front oxygen sensor to obtain an excess air coefficient prediction signal corresponding to the current detection period;

[0081] In the method provided by the embodiment of the application, after entering the current detection period, the front oxygen sensor is continuously predicted according to the predetermined excess air coefficient prediction mode, that is, the excess air coefficient that should be measured by the front oxygen sensor in the ideal state is predicted, until the end time point of the current detection period is reached, and an excess air coefficient prediction signal corresponding to the current detection period is obtained, that is, the signal formed by all the predicted values of the excess air coefficient in the current detection period, the excess air coefficient prediction signal will contain the excess air coefficient prediction value obtained at each prediction time point. Specifically, the excess air coefficient can be estimated based on the actual gas composition in the engine running process to realize the prediction of the excess air coefficient. For example, the estimation based on the air-fuel ratio.

[0082] S105: obtaining an excess air coefficient measured signal measured by the front oxygen sensor in the current detection period;

[0083] In the method provided by the embodiment of the application, the measurement value of the front oxygen sensor is continuously monitored after entering the current detection period, and the excess air coefficient measured value measured by the front oxygen sensor is obtained until the end time point of the current detection period is reached, and the signal composed of the excess air coefficient measured values obtained in the current detection period is taken as the excess air coefficient measured signal.

[0084] S106: determining whether the current detection period is a valid detection period according to the excess air coefficient prediction signal;

[0085] In the method provided by the embodiment of the application, the judgment condition of whether the detection period is valid is set according to the requirement in advance, and the judgment condition is set in combination with the prediction value of the excess air coefficient. It can be understood that the prediction value of the excess air coefficient is an estimated value based on the actual working condition of the engine, which actually reflects the running state of the engine, that is, whether the engine running state in the current detection period can effectively diagnose the non-response fault is determined.

[0086] In the method provided by the embodiment of the application, in the detection process of the current detection period, the processor can determine whether the current excess air coefficient prediction signal meets the corresponding condition according to the pre-set judgment condition, that is, whether the current working condition can realize effective diagnosis for the non-response fault. If the current working condition can realize effective diagnosis, it is determined that the current detection period is a valid detection period, and if the current working condition cannot realize effective diagnosis, it is considered that the current detection period is not a valid detection period.

[0087] In the method provided by the embodiment of the application, if the current detection period is not a valid detection period, the detection process of the current detection period can be directly ended, and the next detection period is entered.

[0088] S107: if the current detection period is a valid detection period, determining a sensor detection result of the current detection period according to the excess air coefficient measured signal; the sensor detection result represents whether the front oxygen sensor has a non-response fault;

[0089] In the method provided by the embodiment of the present application, if the current detection period is a valid detection period, then whether the signal feature of the no-response fault is present in the measured excess air coefficient signal can be identified according to the predetermined fault detection strategy, thereby the no-response fault detection of the front oxygen sensor is performed to obtain the sensor detection result of the current detection period. If the signal feature of the no-response fault is present in the measured excess air coefficient signal, it is determined that the front oxygen sensor has the no-response fault, and if the signal feature of the no-response fault is not present, it is determined that the front oxygen sensor does not have the no-response fault. The way of detecting the no-response fault according to the measured excess air coefficient signal can be set according to actual needs, for example, the change rate or the range of the measured value can be used to determine whether the signal change state of the measured excess air coefficient signal is in the no-response fault state.

[0090] S108: determining whether the current detection period meets the preset detection termination condition;

[0091] In the method provided by the embodiment of the present application, the detection termination condition, that is, the condition for terminating the periodic detection of the front oxygen sensor, can be set according to actual needs in advance, for example, the detection termination condition can be set by limiting the number of valid detection periods, limiting the number of detection periods that have been performed, or limiting the total time length of the periodic detection.

[0092] In the method provided by the embodiment of the present application, after the sensor detection result of the current detection period is obtained, whether the periodic detection process needs to be terminated can be determined according to the preset detection termination condition.

[0093] S109: entering the next detection period;

[0094] In the method provided by the embodiment of the present application, if the current detection period does not meet the detection termination condition, the next detection period is entered, and the process of steps S104 to S108 is performed again.

[0095] S110: ending the periodic detection process of the front oxygen sensor;

[0096] In the method provided by the embodiment of the present application, if the current detection period meets the detection termination condition, the periodic detection process of the front oxygen sensor is completed, and the next detection period is not entered. At the same time, after the periodic detection is ended, the injection amount control of the injector based on the injection amount control signal can be stopped, that is, the injection amount control in the detection state is released, and the normal operation state in which the injection amount control is completed by the control unit of the injector is returned.

[0097] It can be understood that in the fault detection process before this, the injection amount of the injector is continuously controlled based on the injection amount control signal. In order to better illustrate the control of the injection amount, reference can be made to the description of the injection amount control in the foregoing embodiment of the present application.Figure 2 The waveform shown in the blue line. When the front oxygen sensor needs to be diagnosed for failure, the injection amount of the injector will be controlled based on the square wave signal shown in the blue line, and under normal conditions, the excess air factor measured by the front oxygen sensor will present a waveform change shown in the orange line. By identifying the change of the excess air factor measured by the front oxygen sensor under this injection amount control state, it can be identified whether the front oxygen sensor has a non-response failure.

[0098] S111: According to the obtained sensor detection results, determine the failure detection result of the front oxygen sensor.

[0099] The method provided by the embodiment of the application, when the periodic detection process of the front oxygen sensor is ended, the sensor detection results obtained in the periodic detection process, that is, the sensor detection results of each effective detection period, are obtained. It can be understood that in the detection process of each detection period, there is an operation of judging whether the current detection period is an effective detection period. If the detection period is determined to be an effective detection period, the detection period can be referred to as an effective detection period.

[0100] In the method provided by the embodiment of the application, based on the conclusion in each sensor detection result, it is determined whether the possibility of the front oxygen sensor having a non-response failure is greater or the probability of the front oxygen sensor not having a non-response failure is greater, thereby determining the final failure detection result of the front oxygen sensor. Specifically, if the probability of the front oxygen sensor not having a non-response failure is greater in each sensor detection result, the front oxygen sensor not having a non-response failure is taken as the failure detection result. On the contrary, if the probability of the front oxygen sensor having a non-response failure is greater, the front oxygen sensor having a non-response failure is taken as the failure detection result. If the failure detection result indicates that the front oxygen sensor has a non-response failure, an alarm of the non-response failure of the front oxygen sensor is sent.

[0101] Based on the method provided in the embodiment of the application, when it is necessary to detect the fault of the pre-oxygen sensor, a injection quantity control signal is generated; based on the injection quantity control signal, the injection quantity control of the engine is implemented in the detection state, and then it is judged whether the engine is in a stable running state; if the engine is in the stable running state, the pre-oxygen sensor is detected periodically; in the current detection period, the excess air coefficient prediction processing is performed on the pre-oxygen sensor, the excess air coefficient prediction signal corresponding to the current detection period is obtained, and the excess air coefficient measured signal based on the pre-oxygen sensor is obtained; according to the excess air coefficient prediction signal, it is judged whether the current detection period is a valid detection period; if the current detection period is the valid detection period, the sensor detection result of the current detection period is determined according to the excess air coefficient measured signal; it is judged whether the current detection period meets the detection termination condition, and when the current detection period meets the condition, the periodic detection process of the pre-oxygen sensor is ended, and the fault detection result of the pre-oxygen sensor is determined according to the obtained sensor detection results. When the non-response fault of the pre-oxygen sensor is detected by using the method provided in the embodiment of the application, the injection quantity control signal is generated, the injection quantity control of the engine is performed, the fuel injection of the injection quantity control signal is performed, the pre-oxygen sensor enters a state in which the theoretical measurement value should change, the pre-oxygen sensor is detected periodically in the injection state, the predicted excess air coefficient is used to identify whether the effective detection can be performed in the current state, the excess air coefficient measured by the pre-oxygen sensor is used to perform the fault detection when the effective detection can be performed, and therefore the effectiveness of the detection result of each period is ensured. Through the active control of the injection quantity and the judgment of the effectiveness of the detection state, the scene in which the measurement value changes slightly due to various non-fault reasons can be effectively excluded, the excess air coefficient measured by the pre-oxygen sensor can be accurately detected at this time, the fault misreporting can be avoided, the accuracy of the fault detection is improved, and the stable running of the engine is ensured. In addition, the final fault detection result is determined by combining a large number of diagnosis results through the periodic repeated detection, and the accuracy of the fault detection can be further improved.

[0102] In Figure 1 On the basis of the method shown in the figure, in the method provided in the embodiment of the application, the process of generating the injection quantity control signal in step S101 comprises:

[0103] The current original injection quantity control signal, the actual speed of the engine and the actual exhaust flow are obtained.

[0104] In the method provided in the embodiment of the application, the processor can obtain the control signal output by the control unit of the injection quantity, that is, the original set value of the injection quantity. At the same time, the actual speed of the engine and the actual exhaust flow can be obtained from the corresponding monitoring data.

[0105] determining a signal amplitude and a signal frequency according to the actual rotational speed and the actual exhaust flow rate;

[0106] In the method provided by the embodiment of the application, the signal amplitude and the signal frequency corresponding to different rotational speeds and exhaust flow rate ranges are set in advance through experiments, and these data can be stored in the form of a two-dimensional interpolation table. In the fault detection process, the signal amplitude and the signal frequency matched with the actual rotational speed and the actual exhaust flow rate of the engine can be found in the pre-stored data.

[0107] constructing an initial square wave signal based on the signal amplitude and the signal frequency;

[0108] In the method provided by the embodiment of the application, the signal amplitude and the signal frequency are used as the amplitude and the frequency of the square wave signal, and thus an initial square wave signal is generated.

[0109] superimposing the original injection amount control signal and the initial square wave signal, and using the superimposed signal as the injection amount control signal.

[0110] In the method provided by the embodiment of the application, the initial square wave signal is superimposed on the original injection amount control signal, and the superimposed signal is used as the injection amount control signal.

[0111] In the method shown in FIG. 1, Figure 1 On the basis of the method shown in FIG. 1, in the method provided by the embodiment of the application, the process of performing excess air coefficient prediction processing on the front oxygen sensor to obtain an excess air coefficient prediction signal corresponding to the current detection period in step S104 includes:

[0112] determining an air amount signal and a fuel gas amount signal corresponding to the current detection period; the air amount signal represents the air amount flowing through the engine mixer, and the fuel gas amount signal represents the fuel gas amount flowing through the engine injection valve;

[0113] In the method provided by the embodiment of the application, the monitoring signal of the air amount flowing through the engine mixer within the time range of the current detection period can be obtained from the corresponding monitoring data, and the monitoring signal is used as the air amount signal corresponding to the current detection period. Meanwhile, the monitoring signal of the fuel gas amount flowing through the engine injection valve within the time range of the current detection period can be obtained, and the monitoring signal is used as the fuel gas amount signal corresponding to the current detection period.

[0114] respectively performing signal delay processing on the air amount signal and the fuel gas amount signal to obtain a first delay signal corresponding to the air amount signal and a second delay signal corresponding to the fuel gas amount signal;

[0115] In the method provided by the embodiment of the present application, the air quantity signal is subjected to signal delay processing by a predetermined first delay time length, and the processing result is taken as a first delay signal. The fuel gas quantity signal is subjected to signal delay processing by a predetermined second delay time length, and the processing result is taken as a second delay signal. The first delay time length and the second delay time length can be set according to actual requirements, and the two can be the same or different.

[0116] Based on the first delay signal and the second delay signal, an actual air-fuel ratio signal is determined.

[0117] In the method provided by the embodiment of the present application, in the detection process, the actual air-fuel ratio of the engine can be continuously calculated based on the signal value in the first delay signal and the signal value in the second delay signal in real time, so as to obtain the actual air-fuel ratio signal. It can be understood that the actual air-fuel ratio signal contains the actual air-fuel ratio value calculated at each calculation time point, and the actual air-fuel ratio value is the ratio of the air quantity at the time point in the first delay signal to the fuel gas quantity at the time point in the second delay signal.

[0118] An equivalent air-fuel ratio signal corresponding to the current detection period is determined.

[0119] In the method provided by the embodiment of the present application, the current fuel gas component adaptive value can be continuously obtained by the fuel gas adaptive control module, so as to obtain the quality component of the current fuel gas, and the corresponding equivalent air-fuel ratio is matched in real time according to the current quality component, so as to obtain the equivalent air-fuel ratio signal.

[0120] According to the actual air-fuel ratio signal and the equivalent air-fuel ratio signal, a predicted value of the excess air coefficient is calculated in real time, and the predicted value of the excess air coefficient calculated in real time constitutes the excess air coefficient prediction signal.

[0121] In the method provided by the embodiment of the present application, the excess air coefficient is estimated by combining the actual air-fuel ratio and the equivalent air-fuel ratio, the predicted value of the excess air coefficient is obtained, and the excess air coefficient prediction signal is obtained through continuous estimation. Specifically, the ratio of the actual air-fuel ratio to the equivalent air-fuel ratio is taken as the predicted value of the excess air coefficient. The process of obtaining the excess air coefficient prediction signal corresponding to the current detection period is to calculate the predicted value of the excess air coefficient in real time, and at each calculation time point, the ratio of the current actual air-fuel ratio value to the current equivalent air-fuel ratio is taken as the predicted value of the excess air coefficient at the current time point.

[0122] Based on the method provided by the embodiment of the present application, the predicted value of the excess air coefficient is estimated by the actual air-fuel ratio and the equivalent air-fuel ratio, the data acquisition mode is relatively convenient and fast, the operation mode is relatively simple, and the processing efficiency is improved.

[0123] In Figure 1Based on the method shown, in the method provided by the embodiment of the application, the process of judging whether the current detection period is a valid detection period according to the excess air coefficient prediction signal in step S106 comprises:

[0124] obtaining a maximum value of the excess air coefficient prediction value and a minimum value of the excess air coefficient prediction value from the excess air coefficient prediction signal;

[0125] In the method provided by the embodiment of the application, each excess air coefficient prediction value in the excess air coefficient prediction signal can be compared in value to obtain the maximum value and the minimum value, that is, the excess air coefficient prediction value with the maximum value and the excess air coefficient prediction value with the minimum value.

[0126] calculating a first range; the first range is a difference between the maximum value of the excess air coefficient prediction value and the minimum value of the excess air coefficient prediction value;

[0127] In the method provided by the embodiment of the application, the maximum value and the minimum value of the excess air coefficient prediction value are subjected to difference operation, and the difference between the maximum value and the minimum value is taken as the first range.

[0128] judging whether the first range is greater than a preset first range threshold value;

[0129] If the first range is greater than the first range threshold value, it is determined that the current detection period is a valid detection period.

[0130] In the method provided by the embodiment of the application, the first range threshold value can be set in advance according to requirements, and when the range exceeds the threshold value, it is considered that the current working condition can realize effective fault diagnosis. The first range can be compared with the preset first range threshold value, and if the first range is greater than the first range threshold value, it is considered that the current detection period is a valid detection period. If the first range is not greater than the first range threshold value, it is considered that the current detection period is not a valid detection period.

[0131] Based on the method provided by the embodiment of the application, whether the current detection period is a valid detection period is judged through the range of the excess air coefficient prediction signal, that is, whether there is obvious change in the excess air coefficient under ideal state is recognized to identify the valid detection period, which can identify the valid detection period in a relatively convenient manner, guarantees the accuracy of identification of the valid detection period, and is beneficial to improving the processing efficiency.

[0132] In Figure 1 Based on the method shown, in the method provided by the embodiment of the application, the process of determining the sensor detection result corresponding to the current detection period according to the excess air coefficient measured signal in step S107 comprises:

[0133] acquiring a maximum value of the excess air coefficient measured values from the excess air coefficient measured signal, and acquiring a minimum value of the excess air coefficient measured values;

[0134] In the method provided by the embodiment of the application, the maximum value and the minimum value of the excess air coefficient measured values in the excess air coefficient measured signal are compared in value, and the maximum value and the minimum value of the excess air coefficient measured values are acquired, that is, the excess air coefficient measured value with the maximum value and the excess air coefficient measured value with the minimum value are acquired.

[0135] calculating a second range, the second range being a difference between the maximum value of the excess air coefficient measured values and the minimum value of the excess air coefficient measured values;

[0136] In the method provided by the embodiment of the application, the maximum value and the minimum value of the excess air coefficient measured values are subjected to difference operation, and the difference between the two is taken as the second range.

[0137] judging whether the second range is greater than a preset second range threshold value;

[0138] If the second range is greater than the second range threshold value, a conclusion that the front oxygen sensor does not exist the non-response fault is taken as the sensor detection result corresponding to the current detection period.

[0139] In the method provided by the embodiment of the application, the second range threshold value can be set according to requirements in advance. When the range of the excess air coefficient exceeds the threshold value, it is considered that the excess air coefficient presents obvious change, that is, there is no non-response problem. If the range of the excess air coefficient does not exceed the threshold value, it is considered that the change of the excess air coefficient is weak, which does not conform to the ideal situation under the current control state, and there may be a non-response problem. It should be noted that the second range threshold value in the embodiment of the application and the first range threshold value in the foregoing embodiment can be set according to actual requirements, and the two can be equal or not equal.

[0140] In the method provided by the embodiment of the application, in the fault detection process, the second range and the second range threshold value are compared in size. If the second range is greater than the second range threshold value, it is considered that the front oxygen sensor does not exist the non-response fault as the sensor detection result of the current detection period. If the second range is not greater than the second range threshold value, it is considered that the front oxygen sensor exists the non-response fault as the sensor detection result of the current detection period.

[0141] Based on the method provided by the embodiment of the application, whether the excess air coefficient measured signal exists a corresponding change trend is judged through the range of the excess air coefficient measured signal, so that the non-response fault is detected, the data processing process is simple and fast, and the processing efficiency is further improved.

[0142] In Figure 1 Based on the method shown in the description, the method provided by the embodiment of the present application comprises the following steps:

[0143] determining the number of current effective detection periods;

[0144] In the method provided by the embodiment of the present application, the detection termination condition is set based on the number of effective detection periods. When determining whether the current detection period meets the condition, the number of detection periods that have been determined as effective detection periods can be counted, that is, the number of detection periods that have been confirmed as effective detection periods in the current detection period and all detection periods before the current detection period, so as to obtain the number of current effective detection periods. It can be understood that in the periodic detection process, when determining whether each detection period is an effective detection period, whether the detection period is an effective detection period can be recorded, so as to accumulate the number of effective detection periods, for example, by counting by a counter. In the detection termination determination process, the pre-accumulated value can be directly obtained.

[0145] determining whether the number of effective detection periods reaches a preset period number threshold;

[0146] In the method provided by the embodiment of the present application, the period number threshold can be set according to the demand for the number of effective detection periods, for example, 50 effective detection period detection results are required for fault detection, and then the period number threshold can be set to 50.

[0147] In the method provided by the embodiment of the present application, the number of current effective detection periods can be compared with the preset period number threshold to determine whether the current effective detection period has reached the period number threshold.

[0148] If the number of effective detection periods has reached the period number threshold, it is determined that the current detection period meets the detection termination condition.

[0149] In the method provided by the embodiment of the present application, if the number of effective detection periods reaches the period number threshold, it is determined that the current detection period meets the preset detection termination condition. If the number of effective detection periods does not reach the period number threshold, that is, is less than the period number threshold, it is determined that the current detection period does not meet the preset detection termination condition.

[0150] Based on the method provided by the embodiment of the present application, whether to end the periodic detection is determined by the number of effective detection periods, which can ensure that a certain number of sensor detection results are finally obtained, and is beneficial to improve the accuracy of fault detection.

[0151] InFigure 1 Based on the method shown in the method provided by the embodiment of the application, the process of determining the fault detection result of the front oxygen sensor according to the obtained detection results of each sensor in step S111 comprises:

[0152] determining the total number of effective detection periods;

[0153] In the method provided by the embodiment of the application, after the periodic detection process is completed, the total number of detection periods that are judged as effective detection periods in all detection periods can be counted, and the total number is taken as the total number of effective detection periods. According to the mechanism that the sensor detection result is determined only in the effective detection period, the total number of effective detection periods is equal to the total number of sensor detection results.

[0154] It can be understood that if the detection termination condition is set based on whether the number of effective detection periods reaches the preset period number threshold in the foregoing embodiment, the total number of effective detection periods is the preset period number threshold.

[0155] counting the number of sensor detection results representing that the front oxygen sensor does not have a non-response fault, to obtain a non-fault result number;

[0156] In the method provided by the embodiment of the application, the sensor detection result representing that the front oxygen sensor does not have a non-response fault can be identified according to the conclusion in each sensor detection result, the number of the sensor detection result is counted, and the counting result is taken as the non-fault result number. The non-fault result number is also the total number of sensor detection results representing that the front oxygen sensor does not have a non-response fault.

[0157] It should be noted that in the specific implementation process, the number of results representing that there is no fault can be counted in real time during the detection process, for example, recorded by a counter, and the corresponding statistical data can be directly obtained when applied.

[0158] calculating the ratio of the non-fault result number to the total number of effective detection periods, and determining whether the ratio is less than a preset proportion threshold;

[0159] In the method provided by the embodiment of the application, a proportion threshold can be set according to actual needs, and if the proportion of the sensor detection result representing that there is no fault in all results exceeds the proportion threshold, it is considered that the front oxygen sensor does not have a non-response fault.

[0160] In the method provided by the embodiment of the application, in the fault detection process, the ratio of the non-fault result number to the total number of effective detection periods is calculated, and the ratio of the non-fault result number to the total number of effective detection periods is compared with the preset proportion threshold.

[0161] If the ratio is less than the proportion threshold value, a conclusion that the pre-oxygen sensor has a non-response fault is taken as the fault detection result.

[0162] In the method provided by the embodiment of the application, if the ratio of the number of fault-free results to the total number of effective detection periods is less than the proportion threshold value, a non-response fault is taken as the fault detection result of the pre-oxygen sensor, and if the ratio is greater than the proportion threshold value, a result that the pre-oxygen sensor has no non-response fault is taken as the fault detection result. The conclusion corresponding to the case that the ratio is equal to the proportion threshold value can be set according to actual requirements. The ratio equal to the proportion threshold value can be configured to determine that there is no non-response fault, or can be configured to determine that there is a non-response fault.

[0163] Based on the method provided by the embodiment of the application, the proportion of the sensor detection result that indicates that there is no non-response fault in all results is used to determine the final fault determination conclusion, the data processing manner is relatively simple, and the processing efficiency is improved. In addition, the proportion threshold value used to determine whether there is a fault can be flexibly adjusted according to actual requirements, and different fault reporting requirements can be met.

[0164] In order to better illustrate the method provided by the embodiment of the application, on the basis of the method provided by each of the foregoing embodiments, in combination with an actual application scenario, the embodiment of the application provides another method for detecting a fault of a pre-oxygen sensor. The method provided by the embodiment of the application is applied to a non-response fault detection scenario of a pre-oxygen sensor of a vehicle natural gas engine, and the execution subject of the method is an ECU of the vehicle.

[0165] As shown in FIG. 1, the fault detection process provided by the embodiment of the application mainly includes the following steps. Figure 3

[0166] In a case where the engine speed and the load condition meet the fault diagnosis condition, the diagnosis function of the non-response fault is activated. A certain frequency square wave is superimposed on the injection amount of the nozzle, that is, the injection amount set value of the injector, to obtain an injection amount control signal, and the injection amount of the injector is controlled based on the injection amount control signal. The amplitude and frequency of the superimposed square wave are matched in the pre-set amplitude-frequency corresponding data through the engine speed and the exhaust flow to obtain the amplitude and frequency.

[0167] ​The working condition change rate and the oxygen closed loop correction coefficient are confirmed to be stable, and it is judged whether the measured value (measured excess air coefficient) of the oxygen sensor (front oxygen sensor) is within a reasonable range (the upper and lower limits of the reasonable range can be set in advance). The working condition change rate specifically includes the speed change rate and the manifold pressure change rate, and it is judged whether the working condition change rate is stable, that is, whether the speed change rate is less than the corresponding limit value, whether the manifold pressure change rate is less than the corresponding limit value, and whether the oxygen closed loop correction coefficient is stable. The judgment mechanism is the same. After the above conditions are met and for a period of time, the front oxygen sensor is periodically detected, and when the periodic detection is entered, two counters are initialized, one is a denominator counter N0, and the other is a numerator counter N1. The initial values of the two counters are both 0.

[0168] In each detection period, a countdown timer (activation of the countdown timer of tn) is set, and the period of the countdown timer is equal to the period of the injection amount control signal. After the timer is started, the excess air coefficient is continuously predicted within the timing period. The process of predicting the excess air coefficient mainly obtains the air amount signal Q1 flowing through the mixer and the fuel gas amount signal Q2 flowing through the injection valve. Based on the delay times t1 and t2, the signals Q1 and Q2 are time delayed respectively to obtain signals Qt1 and Qt2, so as to obtain the air-fuel ratio value at the position of the exhaust oxygen sensor (i.e. the front oxygen sensor): Qt1 / Qt2. At the same time, by obtaining the adaptive value of the fuel gas component of the engine, the quality component of the current fuel gas is determined, so as to obtain the equivalent air-fuel ratio K. The predicted excess air coefficient λ0 at the current exhaust point, that is, the predicted value of the excess air coefficient, is: λ0=Qt1 / (Qt2·K). The maximum value and the minimum value of the predicted excess air coefficient λ0 in this timing period are continuously captured, and the difference between the current maximum value and the minimum value is taken as the range R0. At the same time, the maximum value and the minimum value of the excess air coefficient λ measured by the front oxygen sensor in this timing period are continuously captured, and the difference between the current maximum value and the minimum value is taken as the range R1.

[0169] When the countdown ends, that is, when the termination time point of the current detection period is reached, the final R0 and R1 of the current detection period are obtained, and R0 and R1 are judged. If R0> limit value Thd0 (the limit value can be set according to actual needs), it is considered that this diagnosis is valid, and the count value of the denominator counter is increased by 1 (i.e. N0+1), otherwise the count value of the denominator counter remains unchanged. If R0> limit value Thd0 and R1> limit value Thd1 (the limit value can be set according to actual needs), the count value of the numerator counter is increased by 1 (i.e. N1+1), otherwise the count value of the numerator counter remains unchanged.

[0170] After the determination for R0 and R1 is completed, it is determined whether the current count value of the denominator counter is greater than the corresponding count limit value, in the embodiment of the application, the maximum count value of the denominator counter is 50, when the count value of the denominator counter reaches 50 (that is, the count value of the denominator counter is greater than 49 for the first time), it is determined whether the ratio of the count value of the numerator counter to the count value of the denominator counter (that is, N1 / N0) is lower than the corresponding preset limit value (the limit value can be set according to actual requirements), if lower than the limit value, it is considered that the correlation between the injection amount and the change of the front oxygen sensor is poor, and a fault is reported, that is, it is determined that the front oxygen sensor has a no-response fault. If (N1 / N0) is higher than the limit value, it is considered that the front oxygen sensor does not have a no-response fault in the current diagnosis process.

[0171] The method provided by the embodiment of the application considers the fluctuations of the injection amount and the air amount, and is beneficial to avoiding false fault reporting in some working conditions where lambda is constant, thereby improving the accuracy of fault diagnosis.

[0172] With Figure 1 Corresponding to the fault detection method of the front oxygen sensor shown in FIG. 1, the embodiment of the application further provides a fault detection device of the front oxygen sensor, which is used for implementing the method shown in FIG. 1, and a structure diagram is shown in FIG. 2. Figure 1 Figure 4 The fault detection device of the front oxygen sensor comprises:

[0173] A signal generation unit 201 is configured to generate an injection amount control signal when it is necessary to detect a fault of the front oxygen sensor, wherein the injection amount control signal is a square wave signal, and the amplitude of the square wave signal represents the injection amount.

[0174] An injection control unit 202 is configured to perform injection amount control on the injector of the engine in a detection state based on the injection amount control signal, and determine whether the engine is in a stable running state after the injection amount control is performed.

[0175] A periodic detection unit 203 is configured to perform periodic detection on the front oxygen sensor if the engine is in the stable running state.

[0176] A coefficient prediction unit 204 is configured to perform excess air coefficient prediction processing on the front oxygen sensor in a current detection period, and obtain an excess air coefficient prediction signal corresponding to the current detection period.

[0177] ​The coefficient measurement unit 205 is used to obtain an excess air coefficient actual measurement signal measured by the front oxygen sensor in the current detection cycle;

[0178] A first judgment unit 206 is configured to judge whether the current detection cycle is a valid detection cycle according to the excess air coefficient prediction signal;

[0179] A first determining unit 207 is configured to determine, if the current detection cycle is a valid detection cycle, a sensor detection result of the current detection cycle based on the excess air coefficient measured signal; the sensor detection result indicates whether the front oxygen sensor has an unresponsive fault;

[0180] a second determining unit 208 for determining whether the current detection cycle meets a preset detection termination condition; if the current detection cycle does not meet the detection termination condition, entering the next detection cycle; if the current detection cycle meets the detection termination condition, terminating the periodic detection process of the front oxygen sensor;

[0181] The second determining unit 209 is configured to determine a fault detection result of the front oxygen sensor according to the obtained detection results of each sensor after the periodic detection process of the front oxygen sensor is completed.

[0182] Using the device provided by an embodiment of the present invention, when detecting a non-responsive front oxygen sensor fault, the device generates an injection quantity control signal and controls the engine's injector accordingly, causing the injector to inject fuel based on the injection quantity control signal. This allows the front oxygen sensor to enter a state where its measured value should theoretically change accordingly. Within this injection state, the front oxygen sensor is periodically tested. During testing, the predicted excess air coefficient is used to determine whether effective detection is possible in the current state. If effective detection is possible, fault detection is performed based on the excess air coefficient measured by the front oxygen sensor, thereby ensuring the validity of each test result. By actively controlling the injection quantity and determining the validity of the test state, scenarios where subtle changes in measured values ​​are caused by non-fault factors can be effectively eliminated. In these cases, accurate fault detection can be performed based on the excess air coefficient measured by the front oxygen sensor, thereby avoiding false fault alarms, improving fault detection accuracy, and ensuring stable engine operation. Furthermore, by periodically repeating testing and combining a large number of diagnostic results to determine the final fault detection result, fault detection accuracy can be further improved.

[0183] exist Figure 4 Based on the device shown, the device provided by the embodiment of the present invention can be further expanded into multiple units. The functions of each unit can be found in the description of the various embodiments provided in the above-mentioned method for detecting the fault of the front oxygen sensor, and no further examples will be given here.

[0184] The embodiment of the present application also provides a storage medium, which comprises stored instructions, wherein when the instructions are executed, the device where the storage medium is located performs the fault detection method of the pre-oxygen sensor as described above.

[0185] The embodiment of the present application also provides an electronic device, a structural schematic diagram of which is shown in Figure 5 The electronic device specifically comprises a memory 301 and one or more than one instruction 302, wherein the one or more than one instruction 302 is stored in the memory 301 and is configured to perform the one or more than one instruction 302 by one or more than one processor 303 to perform the following operations:

[0186] When it is necessary to perform fault detection on the pre-oxygen sensor, a spraying amount control signal is generated; the spraying amount control signal is a square wave signal, and the amplitude of the square wave signal represents the spraying amount;

[0187] The spraying amount control signal is used to perform spraying amount control on the spraying of the engine in a detection state, and after the spraying amount control is performed, it is judged whether the engine is in a stable operation state;

[0188] If the engine is in the stable operation state, the pre-oxygen sensor is subjected to periodic detection;

[0189] In the current detection period, excess air coefficient prediction processing is performed on the pre-oxygen sensor to obtain an excess air coefficient prediction signal corresponding to the current detection period;

[0190] An excess air coefficient measured signal based on the excess air coefficient measured by the pre-oxygen sensor in the current detection period is obtained;

[0191] According to the excess air coefficient prediction signal, it is judged whether the current detection period is a valid detection period;

[0192] If the current detection period is the valid detection period, the excess air coefficient measured signal is used to determine a sensor detection result of the current detection period; the sensor detection result represents whether the pre-oxygen sensor has a non-response fault;

[0193] It is judged whether the current detection period meets a preset detection termination condition, if the current detection period does not meet the detection termination condition, the next detection period is entered, and if the current detection period meets the detection termination condition, the periodic detection process of the pre-oxygen sensor is ended;

[0194] After the periodic detection process of the pre-oxygen sensor is ended, a fault detection result of the pre-oxygen sensor is determined according to the obtained sensor detection results.

[0195] The electronic device in the embodiments of the present application can be an ECU (Electronic Control Unit), a VCU (Vehicle Control Unit), an MCU (Micro Controller Unit), an HCU (Hybrid Control Unit), etc.

[0196] Each of the embodiments in the present specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, for the system or system embodiments, since it is basically similar to the method embodiments, it is described more simply, and the related parts can be referred to the part of the method embodiments. The above-described system and system embodiments are merely illustrative, and the units described as separate components can be or can not be physically separated, and the components shown as units can be or can not be physical units, i.e., they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiments according to the actual needs. Those skilled in the art can understand and implement it without creative labor.

[0197] The skilled in the art can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed in the present text can be realized in electronic hardware, computer software or combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in general in the above description. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0198] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of failure detection of a front oxygen sensor, characterized by, The method comprises the steps of: generating an injection amount control signal when it is necessary to perform fault detection on the front oxygen sensor; the injection amount control signal is a square wave signal, and the amplitude of the square wave signal represents the injection amount; performing injection amount control on the injection of the engine in a detection state based on the injection amount control signal, and determining whether the engine is in a stable operating state after the injection amount control is performed; if the engine is in a stable operating state, periodically detecting the front oxygen sensor; in the current detection period, performing excess air coefficient prediction processing on the front oxygen sensor to obtain an excess air coefficient prediction signal corresponding to the current detection period; obtaining an excess air coefficient actual measurement signal based on the excess air coefficient measured by the front oxygen sensor in the current detection period; determining whether the current detection period is a valid detection period according to the excess air coefficient prediction signal; if the current detection period is a valid detection period, determining a sensor detection result of the current detection period according to the excess air coefficient actual measurement signal; the sensor detection result represents whether the front oxygen sensor has a non-response fault; determining whether the current detection period meets a preset detection termination condition, if the current detection period does not meet the detection termination condition, entering a next detection period, and if the current detection period meets the detection termination condition, ending the periodic detection process of the front oxygen sensor; after the periodic detection process of the front oxygen sensor is ended, determining a fault detection result of the front oxygen sensor according to the obtained sensor detection results.

2. The method of detecting a failure of a front oxygen sensor according to claim 1, characterized by, The method comprises the steps of: obtaining a current original injection amount control signal, an actual speed of the engine, and an actual exhaust flow rate; determining a signal amplitude and a signal frequency according to the actual speed and the actual exhaust flow rate; constructing an initial square wave signal based on the signal amplitude and the signal frequency; superimposing the original injection amount control signal and the initial square wave signal, and taking the superimposed signal as the injection amount control signal.

3. The method of detecting a failure of a front oxygen sensor according to claim 1, characterized by, The method comprises the steps of: determining an air amount signal and a fuel gas amount signal corresponding to the current detection period; the air amount signal represents the amount of air flowing through the engine mixer, and the fuel gas amount signal represents the amount of fuel gas flowing through the engine injection valve; respectively performing signal delay processing on the air amount signal and the fuel gas amount signal to obtain a first delay signal corresponding to the air amount signal and a second delay signal corresponding to the fuel gas amount signal; determining an actual air-fuel ratio signal based on the first delay signal and the second delay signal; determining an equivalent air-fuel ratio signal corresponding to the current detection period; real-time calculating a predicted value of the excess air coefficient according to the actual air-fuel ratio signal and the equivalent air-fuel ratio signal, and the predicted value of the excess air coefficient obtained by real-time calculation constitutes the excess air coefficient prediction signal.

4. The method of detecting a failure of a front oxygen sensor according to claim 1, characterized by, The method comprises the steps of: obtaining a maximum value of the excess air coefficient prediction value from the excess air coefficient prediction signal, and obtaining a minimum value of the excess air coefficient prediction value; calculating a first range difference; the first range difference being a difference between the maximum value of the excess air coefficient prediction value and the minimum value of the excess air coefficient prediction value; determining whether the first range difference is greater than a preset first range difference threshold value; if the first range difference is greater than the first range difference threshold value, determining that the current detection period is a valid detection period.

5. The method of detecting a failure of a front oxygen sensor according to claim 1, characterized by, the determination of the sensor detection result corresponding to the current detection period according to the excess air coefficient measured signal comprises: obtaining a maximum value of the excess air coefficient measured value from the excess air coefficient measured signal, and obtaining a minimum value of the excess air coefficient measured value; calculating a second range difference; the second range difference being a difference between the maximum value of the excess air coefficient measured value and the minimum value of the excess air coefficient measured value; determining whether the second range difference is greater than a preset second range difference threshold value; if the second range difference is greater than the second range difference threshold value, regarding a conclusion that the pre-oxygen sensor does not exist a non-response fault as the sensor detection result corresponding to the current detection period.

6. The method of detecting a failure of a front oxygen sensor according to claim 1, characterized by, the determination of whether the current detection period meets a preset detection termination condition comprises: determining a current valid detection period number; determining whether the valid detection period number reaches a preset period number threshold value; if the valid detection period number has reached the period number threshold value, determining that the current detection period meets the detection termination condition.

7. The method of detecting a failure of a front oxygen sensor according to claim 1, characterized by, the determination of the fault detection result of the pre-oxygen sensor according to the obtained sensor detection results comprises: determining a total number of valid detection periods; counting the number of sensor detection results representing that the pre-oxygen sensor does not exist a non-response fault to obtain a non-fault result number; calculating a ratio of the non-fault result number to the total number of valid detection periods, and determining whether the ratio is less than a preset proportion threshold value; if the ratio is less than the proportion threshold value, regarding a conclusion that the pre-oxygen sensor exists a non-response fault as the fault detection result.

8. A fault detection device for a front oxygen sensor, characterized in that: comprise: a signal generation unit configured to generate an injection amount control signal when it is necessary to perform fault detection on a pre-oxygen sensor; the injection amount control signal is a square wave signal, and an amplitude of the square wave signal represents an injection amount; an injection control unit configured to perform injection amount control on an injection state of an injector of an engine based on the injection amount control signal, and determine whether the engine is in a stable operation state after the injection amount control is performed; a period detection unit configured to perform periodic detection on the pre-oxygen sensor if the engine is in the stable operation state; a coefficient prediction unit configured to perform excess air coefficient prediction processing on the pre-oxygen sensor in a current detection period to obtain an excess air coefficient prediction signal corresponding to the current detection period; a coefficient measurement unit configured to obtain an excess air coefficient measured signal measured based on the pre-oxygen sensor in the current detection period; The first judging unit is configured to judge whether the current detection period is a valid detection period according to the excess air coefficient prediction signal; The first determining unit is configured to determine a sensor detection result of the current detection period according to the excess air coefficient actual measurement signal if the current detection period is a valid detection period; the sensor detection result represents whether the front oxygen sensor has a non-response fault; The second judging unit is configured to judge whether the current detection period meets a preset detection termination condition; if the current detection period does not meet the detection termination condition, the next detection period is entered; if the current detection period meets the detection termination condition, the periodic detection process of the front oxygen sensor is ended; The second determining unit is configured to determine a fault detection result of the front oxygen sensor according to the obtained sensor detection results after the periodic detection process of the front oxygen sensor is ended.

9. A storage medium, characterized by The storage medium comprises stored instructions, wherein the instructions, when executed, control a device in which the storage medium is located to perform the fault detection method of the front oxygen sensor according to any one of claims 1 to 7.

10. An electronic device, comprising: The computer program product comprises a memory and one or more instructions, wherein the one or more instructions are stored in the memory and are configured to be executed by one or more processors to perform the fault detection method of the front oxygen sensor according to any one of claims 1 to 7.

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