Air-fuel ratio sensor diagnosis method, device, apparatus, and storage medium

Abstract

The application belongs to the technical field of vehicle detection, and discloses a diagnostic method, device and equipment for an air-fuel ratio sensor and a storage medium. The application determines the current diagnostic type according to the air-fuel ratio change cumulative parameter of the vehicle when the vehicle is cut off. If the air-fuel ratio change cumulative parameter meets the active diagnostic condition corresponding to the current diagnostic type, the vehicle is controlled to perform invasive enrichment, and the air-fuel ratio delay parameter is determined. The current diagnostic parameter is calculated according to the air-fuel ratio delay parameter and the historical diagnostic parameter. If the total number of invasive enrichments is greater than the preset number, it is determined whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnostic parameter. Since it is determined in advance according to the air-fuel ratio change cumulative parameter whether diagnosis is needed and the diagnostic type, unnecessary active diagnosis is reduced as much as possible. When active diagnosis is needed, the historical diagnostic parameter is used for fault judgment, the number of invasive enrichments is reduced as much as possible, and the influence of diagnosis on emissions is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle detection, and in particular to a diagnostic method, device and equipment for an air-fuel ratio sensor and a storage medium. BACKGROUND

[0002] Nowadays, with more and more emphasis on environmental protection, the fault emission limit of the OBD system of a vehicle is more stringent, and the noble metal content of a catalytic converter is required more. In the diagnostic items of the OBD system, the air-fuel ratio sensor response delay diagnosis of emission becomes a key factor affecting the noble metal of the catalytic converter, because:

[0003] When the air-fuel ratio sensor is fault-free, diagnosis will also force enrichment, thereby causing emission deterioration. In order to ensure diagnostic accuracy, 2 or more enrichments are required for each diagnosis to make a judgment, which further aggravates the deterioration of emission, and thus the air-fuel ratio sensor response delay diagnosis becomes the most deteriorated diagnostic item of emission.

[0004] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a diagnostic method, device and equipment for an air-fuel ratio sensor and a storage medium, which aims to solve the technical problem of excessive emission deterioration in the response delay diagnosis of the air-fuel ratio sensor in the prior art.

[0006] To achieve the above purpose, the present application provides a diagnostic method for an air-fuel ratio sensor, which comprises the following steps:

[0007] When the vehicle is out of fuel, the current diagnostic type is determined according to the air-fuel ratio change cumulative parameter of the vehicle;

[0008] If the air-fuel ratio change cumulative parameter meets the active diagnostic condition corresponding to the current diagnostic type, the vehicle is controlled to perform invasive enrichment, and an air-fuel ratio delay parameter is determined;

[0009] The current diagnostic parameter is calculated according to the air-fuel ratio delay parameter and the historical diagnostic parameter;

[0010] If the total number of invasive enrichments is greater than a preset number, it is determined whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnostic parameter.

[0011] Optionally, the step of determining the current diagnostic type according to the air-fuel ratio change cumulative parameter of the vehicle when the vehicle is out of fuel comprises:

[0012] When the vehicle is out of fuel, the air-fuel ratio signal is obtained at intervals of a preset time length;

[0013] determining a cumulative parameter of air-fuel ratio change according to the air-fuel ratio signal and a historical cumulative parameter of air-fuel ratio change;

[0014] determining a current diagnosis type according to the cumulative parameter of air-fuel ratio change when the number of times of calculation reaches a preset threshold.

[0015] Optionally, the step of acquiring the air-fuel ratio signal at intervals of a preset time length when the vehicle is fuel-cut comprises:

[0016] detecting whether the air-fuel ratio signal of the air-fuel ratio sensor is in a preset interval when the vehicle is fuel-cut;

[0017] if the air-fuel ratio signal is in the preset interval, acquiring the air-fuel ratio signal at intervals of the preset time length.

[0018] Optionally, the step of determining the cumulative parameter of air-fuel ratio change according to the air-fuel ratio signal and a historical cumulative parameter of air-fuel ratio change comprises:

[0019] determining an air-fuel ratio change amount according to the air-fuel ratio signal and a previously acquired air-fuel ratio signal;

[0020] performing weighted summation on the air-fuel ratio change amount and the historical cumulative parameter of air-fuel ratio change according to a preset weighting coefficient to obtain the cumulative parameter of air-fuel ratio change.

[0021] Optionally, before the step of controlling the vehicle to perform intrusive enrichment to determine an air-fuel ratio delay parameter if the cumulative parameter of air-fuel ratio change meets an active diagnosis condition corresponding to the current diagnosis type, the method further comprises:

[0022] searching for a parameter determination interval corresponding to the current diagnosis type;

[0023] if the cumulative parameter of air-fuel ratio change is in the parameter determination interval, detecting whether the vehicle meets an active diagnosis enabling condition;

[0024] if the vehicle meets the active diagnosis enabling condition, determining that the cumulative parameter of air-fuel ratio change meets the active diagnosis condition corresponding to the current diagnosis type.

[0025] Optionally, the step of detecting whether the vehicle meets the active diagnosis enabling condition if the cumulative parameter of air-fuel ratio change is in the parameter determination interval comprises:

[0026] if the cumulative parameter of air-fuel ratio change is in the parameter determination interval, acquiring an engine operating parameter of the vehicle, the engine operating parameter comprising at least one of an intake air amount, an intake air change amount, a rotation speed, a rotation speed change amount, and an air-fuel ratio of the vehicle engine;

[0027] detecting whether the engine operating parameter is in a preset detection interval.

[0028] If the vehicle is in the preset detection interval, it is determined that the vehicle meets the active diagnosis enabling condition.

[0029] Optionally, if the total number of intrusive enrichment is greater than the preset number, the step of determining whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnosis parameter comprises:

[0030] If the total number of intrusive enrichment is greater than the preset number, the fault detection threshold value corresponding to the current diagnosis type is searched;

[0031] If the current diagnosis type is rich-to-lean type and the current diagnosis parameter is less than the fault detection threshold value, it is determined that the air-fuel ratio sensor of the vehicle has a response delay fault;

[0032] If the current diagnosis type is lean-to-rich type and the current diagnosis parameter is greater than the fault detection threshold value, it is determined that the air-fuel ratio sensor of the vehicle has a response delay fault.

[0033] In addition, to achieve the above-mentioned purpose, the present application also proposes an air-fuel ratio sensor diagnosis device, which comprises the following modules:

[0034] A type determination module is configured to determine the current diagnosis type according to the air-fuel ratio change cumulative parameter of the vehicle when the vehicle is cut off oil;

[0035] A delay diagnosis module is configured to control the vehicle to perform intrusive enrichment to determine the air-fuel ratio delay parameter if the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnosis type;

[0036] A parameter calculation module is configured to calculate the current diagnosis parameter according to the air-fuel ratio delay parameter and the historical diagnosis parameter;

[0037] A fault judgment module is configured to determine whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnosis parameter if the total number of intrusive enrichment is greater than the preset number.

[0038] In addition, to achieve the above-mentioned purpose, the present application also proposes an air-fuel ratio sensor diagnosis device, which comprises: a processor, a memory, and an air-fuel ratio sensor diagnosis program stored in the memory and executable by the processor, the air-fuel ratio sensor diagnosis program implements the steps of the air-fuel ratio sensor diagnosis method as described above when executed.

[0039] Further, in order to achieve the above object, the present application also provides a computer-readable storage medium having stored thereon an air-fuel ratio sensor diagnosis program which, when executed, implements the steps of the air-fuel ratio sensor diagnosis method described above.

[0040] The present application determines the current diagnosis type according to the air-fuel ratio change cumulative parameter when the vehicle is cut off, and controls the vehicle to perform invasive enrichment to determine the air-fuel ratio delay parameter if the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnosis type. The current diagnosis parameter is calculated according to the air-fuel ratio delay parameter and the historical diagnosis parameter, and it is determined whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnosis parameter if the total number of invasive enrichments is greater than a preset number. Since it is determined in advance according to the air-fuel ratio change cumulative parameter whether diagnosis is needed and the diagnosis type, unnecessary active diagnosis using invasive enrichment is reduced as much as possible, and when active diagnosis is needed, the historical diagnosis parameter is used for fault judgment, so that the number of invasive enrichments is reduced as much as possible, thereby reducing the impact of diagnosis on emissions. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structural schematic diagram of an electronic device related to a hardware running environment of an embodiment of the present application;

[0042] Figure 2 is a flowchart of an air-fuel ratio sensor diagnosis method first embodiment of the present application;

[0043] Figure 3 is a flowchart of an air-fuel ratio sensor diagnosis method second embodiment of the present application;

[0044] Figure 4 is a flowchart of an air-fuel ratio sensor diagnosis method third embodiment of the present application;

[0045] Figure 5 is a structural block diagram of an air-fuel ratio sensor diagnosis device first embodiment of the present application.

[0046] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0047] It should be understood that the specific embodiments described herein are merely illustrative of the present application and do not limit the present application.

[0048] Reference Figure 1 , Figure 1 is a structural schematic diagram of an air-fuel ratio sensor diagnosis device related to a hardware running environment of an embodiment of the present application.

[0049] As Figure 1As shown, the electronic device can include a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize the connection and communication between the components. The user interface 1003 can include a display, an input unit such as a keyboard, and can also include a standard wired interface, a wireless interface. The network interface 1004 can optionally include a standard wired interface, a wireless interface (such as a wireless fidelity (WI-FI) interface). The memory 1005 can be a high-speed random access memory (RAM), and can also be a stable non-volatile memory (NVM), such as a disk memory. The memory 1005 can also be a storage device independent of the aforementioned processor 1001.

[0050] Those skilled in the art can understand that Figure 1 The structure shown in the figure does not constitute a limitation on the electronic device, and can include more or fewer components than the figure, or combine certain components, or different component arrangements.

[0051] As Figure 1 As shown, the memory 1005 as a storage medium can include an operating system, a network communication module, a user interface module, and an air-fuel ratio sensor diagnosis program.

[0052] In Figure 1 In the electronic device shown, the network interface 1004 is mainly used for data communication with a network server; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the electronic device of the present application can be arranged in an air-fuel ratio sensor diagnosis device, and the electronic device calls the air-fuel ratio sensor diagnosis program stored in the memory 1005 through the processor 1001, and executes the air-fuel ratio sensor diagnosis method provided by the embodiment of the present application.

[0053] The embodiment of the present application provides an air-fuel ratio sensor diagnosis method, which refers to Figure 2 , Figure 2 The flowchart of a first embodiment of an air-fuel ratio sensor diagnosis method of the present application.

[0054] In this embodiment, the air-fuel ratio sensor diagnosis method includes the following steps:

[0055] Step S10: When the vehicle is cut off, determine the current diagnosis type according to the air-fuel ratio change accumulation parameter of the vehicle.

[0056] It should be noted that the execution subject of the embodiment can be the air-fuel ratio sensor diagnostic device (referred to as diagnostic device for short) or the vehicle itself, and the diagnostic device can be a controller such as an ECU controller or other similar controller that can control the OBD system to perform diagnosis. The embodiment is not limited in this regard, and the air-fuel ratio sensor diagnostic method of the present application is described below with the diagnostic device as an example.

[0057] It should be noted that the vehicle fuel cut can be that the vehicle stops supplying fuel to the engine, and the air-fuel ratio change cumulative parameter can be a quantitative parameter constructed according to the change amount of the air-fuel ratio of the vehicle at a certain time, which is used to determine the specific diagnostic type and whether to perform a delayed active diagnosis. The diagnostic type can be divided into two types: rich to lean type and lean to rich type.

[0058] In a specific implementation, determining the current diagnostic type according to the air-fuel ratio change cumulative parameter can be detecting whether the air-fuel ratio change cumulative parameter is a positive number. If it is a positive number, it is determined that the current diagnostic type is the rich to lean type (RICH->LEAN diagnostic type), and at this time the change of the air-fuel ratio is from rich to lean. If it is not a positive number, it is determined that the current diagnostic type is the lean to rich type (LEAN->RICH diagnostic type), and at this time the change of the air-fuel ratio is from lean to rich.

[0059] Step S20: If the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnostic type, control the vehicle to perform an invasive enrichment, and determine an air-fuel ratio delay parameter.

[0060] It should be noted that if the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnostic type, it means that the vehicle needs to be actively diagnosed for the air-fuel ratio at this time. At this time, the vehicle can be controlled to perform an invasive enrichment operation, and the air-fuel ratio active diagnosis is performed during the enrichment process, so as to obtain the air-fuel ratio delay parameter.

[0061] Among them, the active diagnosis conditions corresponding to different diagnostic types are different. Specifically, the active diagnosis condition can be set by the management personnel of the diagnostic device according to actual needs, and the embodiment is not limited in this regard.

[0062] Step S30: Calculate the current diagnostic parameter according to the air-fuel ratio delay parameter and the historical diagnostic parameter.

[0063] It should be noted that the current diagnostic parameter can be calculated according to the air-fuel ratio delay parameter and the historical diagnostic parameter by weighting and summing the air-fuel ratio delay parameter and the historical diagnostic parameter according to a preset delay coefficient, so as to obtain the current diagnostic parameter. The historical diagnostic parameter can be a diagnostic parameter generated in the previous air-fuel ratio delay diagnosis, and the preset delay coefficient can be set by the management personnel of the diagnostic device according to actual needs, for example, the preset delay coefficient is set to 0.8.

[0064] Specifically, the current diagnostic parameter can be obtained by weighting and summing the air-fuel ratio delay parameter and the historical diagnostic parameter according to a preset delay coefficient through a diagnostic parameter calculation formula, and the diagnostic parameter calculation formula can be:

[0065] P now =S*(1-a)+P*a

[0066] In the formula, a is a preset delay coefficient setting, S is an air-fuel ratio delay parameter, P is a historical diagnostic parameter, and P now is a current diagnostic parameter.

[0067] Step S40: If the total number of invasive enrichment is greater than the preset number, determining whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnostic parameter.

[0068] It should be noted that the total number of invasive enrichment can be the total number of invasive enrichment operations, and the preset number can be set by the management personnel of the diagnostic device in advance, for example, the preset number is set to 4.

[0069] In a specific implementation, if the total number of invasive enrichment is greater than the preset number, it means that the number of invasive enrichment at this time has exceeded the preset number, that is, the air-fuel ratio sensor has been actively diagnosed for a large number of times, and at this time the accuracy of the current diagnostic parameter calculated will be higher, so the current diagnostic parameter can be used to determine whether the air-fuel ratio sensor has a response delay fault.

[0070] In a specific implementation, the current diagnostic parameter can be compared with a preset diagnostic threshold, and whether the air-fuel ratio sensor of the vehicle has a response delay fault can be determined according to the comparison result. The preset diagnostic threshold can be set by the management personnel of the diagnostic device according to actual needs.

[0071] In a specific implementation, because the diagnostic types are different, the positive and negative relationships of the current diagnostic parameter values calculated are also different, and the judgment methods for determining whether there is a response delay fault are also different, so the step S40 of the embodiment can include:

[0072] If the total number of intrusive enrichment is greater than the preset number, the fault detection threshold corresponding to the current diagnosis type is searched;

[0073] When the current diagnosis type is the rich-to-lean type and the current diagnosis parameter is less than the fault detection threshold, it is determined that the air-fuel ratio sensor of the vehicle has a response delay fault.

[0074] When the current diagnosis type is the lean-to-rich type and the current diagnosis parameter is greater than the fault detection threshold, it is determined that the air-fuel ratio sensor of the vehicle has a response delay fault.

[0075] It should be noted that the values of the fault detection thresholds corresponding to different diagnosis types are also the same, and the fault detection thresholds can be set by the management personnel of the diagnosis equipment according to actual needs.

[0076] In a specific implementation, if the diagnosis type is the rich-to-lean type, the finally calculated current diagnosis parameter is a positive number, and the current diagnosis parameter of a faulty vehicle is generally less than the diagnosis parameter of a normal vehicle. Therefore, the current diagnosis parameter can be compared with the fault detection threshold, and when the current diagnosis parameter is less than the fault detection threshold, it is determined that the air-fuel ratio sensor of the vehicle has a response delay fault when the air-fuel ratio changes from rich to lean. When the current diagnosis parameter is greater than or equal to the fault detection threshold, it is determined that the air-fuel ratio sensor of the vehicle does not have a response delay fault.

[0077] If the diagnosis type is the lean-to-rich type, the finally calculated current diagnosis parameter is a negative number, and the current diagnosis parameter of a faulty vehicle is generally greater than the diagnosis parameter of a normal vehicle. Therefore, the current diagnosis parameter can be compared with the fault detection threshold, and when the current diagnosis parameter is greater than the fault detection threshold, it is determined that the air-fuel ratio sensor of the vehicle has a response delay fault when the air-fuel ratio changes from lean to rich. When the current diagnosis parameter is less than or equal to the fault detection threshold, it is determined that the air-fuel ratio sensor of the vehicle does not have a response delay fault.

[0078] In this embodiment, when the vehicle is cut off, the current diagnosis type is determined according to the air-fuel ratio change cumulative parameter of the vehicle. If the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnosis type, the vehicle is controlled to perform intrusive enrichment to determine the air-fuel ratio delay parameter. The current diagnosis parameter is calculated according to the air-fuel ratio delay parameter and the historical diagnosis parameter. If the total number of intrusive enrichment is greater than the preset number, it is determined whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnosis parameter. Since it is determined in advance whether diagnosis is needed and the diagnosis type according to the air-fuel ratio change cumulative parameter, unnecessary active diagnosis using intrusive enrichment is reduced as much as possible. When active diagnosis is needed, fault judgment is performed using the historical diagnosis parameter, and the number of intrusive enrichment is reduced as much as possible, thereby reducing the impact of diagnosis on emissions.

[0079] Reference Figure 3 , Figure 3 Flowchart of a second embodiment of the air-fuel ratio sensor diagnosis method of the present application.

[0080] Based on the above first embodiment, the step S10 of the air-fuel ratio sensor diagnosis method of the present embodiment comprises:

[0081] Step S101: When the vehicle is fuel-cut, the air-fuel ratio signal is acquired at intervals of a preset time length.

[0082] It should be noted that the air-fuel ratio signal can be a signal generated after the air-fuel ratio sensor collects data, and the preset time length can be set in advance by the administrator of the diagnosis device according to actual needs, for example: if the preset time length is set to 100 ms, the diagnosis device will read the air-fuel ratio signal from the air-fuel ratio sensor once every 100 ms.

[0083] Of course, the air-fuel ratio signal generated after the air-fuel ratio sensor collects data can also be sent to the diagnosis device for storage, and at this time, acquiring the air-fuel ratio signal at intervals of a preset time length can be to select a time as a starting time, acquire the air-fuel ratio signal at the starting time, and then read the air-fuel ratio signal at intervals of 100 ms from the starting time, for example: assuming that the starting time is 0 ms, then the air-fuel ratio signal at times of 100 ms, 200 ms,..., n*100 ms, etc. is acquired.

[0084] Further, after fuel-cut, the air-fuel ratio will change greatly, and when the air-fuel ratio is within a certain range, it will be more convenient to observe, so as to improve the judgment accuracy of whether to perform a delay active diagnosis, and at this time, the step S101 of the present embodiment can comprise:

[0085] When the vehicle is fuel-cut, it is detected whether the air-fuel ratio signal of the air-fuel ratio sensor is within a preset interval.

[0086] If it is within the preset interval, the air-fuel ratio signal is acquired at intervals of a preset time length.

[0087] It should be noted that the preset interval can be set in advance by the administrator of the diagnosis device according to actual conditions, for example: if the value of the air-fuel ratio signal is between 55% and 75%, the change amount of the air-fuel ratio can be accurately judged to determine whether to perform a delay active diagnosis, and the preset interval can be set to 55%-75%.

[0088] It can be understood that if the air-fuel ratio signal of the air-fuel ratio sensor is within the preset interval, it indicates that the judgment accuracy is high at this time, and therefore the air-fuel ratio signal can be acquired at intervals of a preset time length.

[0089] Step S102: determining the air-fuel ratio change accumulation parameter according to the air-fuel ratio signal and the historical change accumulation parameter.

[0090] It should be noted that the determination of the air-fuel ratio change accumulation parameter according to the air-fuel ratio signal and the historical change accumulation parameter can be to compare the current acquired air-fuel ratio signal with the last acquired air-fuel ratio signal, to determine the air-fuel ratio change amount, and to take the average value between the air-fuel ratio change amount and the historical change accumulation parameter as the air-fuel ratio change accumulation parameter. The air-fuel ratio change accumulation parameter is a quantitative parameter for indicating the amplitude of the air-fuel ratio change amount within a certain time.

[0091] In a specific implementation, in order to make the air-fuel ratio change accumulation parameter more consistent with the actual situation, the step S102 in the embodiment can include:

[0092] determining the air-fuel ratio change amount according to the air-fuel ratio signal and the last acquired air-fuel ratio signal;

[0093] performing weighted summation on the air-fuel ratio change amount and the historical change accumulation parameter according to a preset weighting coefficient, to obtain the air-fuel ratio change accumulation parameter.

[0094] In actual use, the determination of the air-fuel ratio change amount according to the air-fuel ratio signal and the last acquired air-fuel ratio signal can be to subtract the value in the last acquired air-fuel ratio signal from the value in the air-fuel ratio signal, to obtain the air-fuel ratio change amount.

[0095] It should be noted that the preset weighting coefficient can be set by the management personnel of the diagnostic device according to actual needs, for example, the preset weighting coefficient is set to 0.8.

[0096] In a specific implementation, the air-fuel ratio change accumulation parameter can be calculated by performing weighted summation on the air-fuel ratio change amount and the historical change accumulation parameter according to the preset weighting coefficient through a preset parameter weighting formula.

[0097] The preset parameter weighting formula can be:

[0098] S ac = S now (1-α) + S hac *α

[0099] In the formula, S ac is the air-fuel ratio change accumulation parameter, α is the preset weighting coefficient, S now is the air-fuel ratio change amount, and S hac is the historical change accumulation parameter.

[0100] It should be understood that, since the historical change cumulative parameter is obtained according to the previously collected data, and the air-fuel ratio change amount calculated from the air-fuel ratio signal is only the change amount of the most recent time, the importance of the two is inconsistent, and the parameter obtained by directly averaging may not meet the actual needs, therefore, the corresponding preset weighting coefficient can be set according to the actual importance procedure, and the air-fuel ratio change amount and the historical change cumulative parameter are weighted and summed according to the preset weighting coefficient, so that the obtained air-fuel ratio change cumulative parameter is more in line with the actual situation.

[0101] Step S103: When the number of calculations reaches the preset number threshold, determining the current diagnosis type according to the air-fuel ratio change cumulative parameter.

[0102] It should be noted that, if the number of calculations reaches the preset number threshold, it means that the air-fuel ratio signal used to calculate the air-fuel ratio change cumulative parameter at this time is already relatively large, and the air-fuel ratio change cumulative parameter obtained at this time can accurately reflect the actual condition of the vehicle air-fuel ratio sensor, therefore, the current diagnosis type can be determined according to the air-fuel ratio change cumulative parameter.

[0103] The embodiment obtains the air-fuel ratio signal at intervals of a preset time length when the vehicle is fuel cut; determines the air-fuel ratio change cumulative parameter according to the air-fuel ratio signal and the historical change cumulative parameter; and when the number of calculations reaches the preset number threshold, determines the current diagnosis type according to the air-fuel ratio change cumulative parameter. Since multiple air-fuel ratio signals are obtained, and the air-fuel ratio change cumulative parameter is obtained by cumulative calculation according to the multiple air-fuel ratio signals, when the number of calculations reaches the preset number threshold, it is determined according to the air-fuel ratio change cumulative parameter whether active diagnosis is needed, and when diagnosis is needed, it is determined whether the diagnosis type is from rich to lean or from lean to rich, thereby ensuring the reliability of the air-fuel ratio sensor diagnosis method during execution.

[0104] Reference Figure 4 , Figure 4 is a flowchart of an air-fuel ratio sensor diagnosis method according to a third embodiment of the present application.

[0105] Based on the above-mentioned first embodiment, the air-fuel ratio sensor diagnosis method of the present embodiment further comprises, before the step S20:

[0106] Step S11: searching for a parameter determination interval corresponding to the current diagnosis type.

[0107] It should be noted that the parameter determination interval corresponding to different current diagnosis types is also different, and the specific parameter determination interval can be set by the manager of the diagnosis equipment in advance. For example, in order to distinguish two different diagnosis types, the manager of the diagnosis equipment can set four interval thresholds, which are a first threshold, a second threshold, a third threshold and a fourth threshold. The parameter determination interval corresponding to the rich-to-lean type is greater than or equal to the second threshold and less than or equal to the first threshold, and the parameter determination interval corresponding to the lean-to-rich type is greater than or equal to the fourth threshold and less than or equal to the third threshold.

[0108] Step S12: If the air-fuel ratio change cumulative parameter is in the parameter determination interval, it is detected whether the vehicle satisfies the active diagnosis enabling condition.

[0109] It can be understood that if the air-fuel ratio change cumulative parameter is in the parameter determination interval, it indicates that the air-fuel ratio sensor of the vehicle at this time may have a response delay fault and needs to be diagnosed. At this time, it is also necessary to judge whether the vehicle supports the delay active diagnosis, and whether the vehicle satisfies the active diagnosis enabling condition can be detected.

[0110] In a specific implementation, if the air-fuel ratio change cumulative parameter is extremely large or extremely small, it indicates that the air-fuel ratio changes too fast or too slow, and at this time, the delay active diagnosis is actually not needed, and whether the air-fuel ratio sensor has a response delay fault can be determined. Therefore, if the air-fuel ratio change cumulative parameter is not in the parameter determination interval, the delay active diagnosis can not be performed, and whether the air-fuel ratio sensor has a response delay fault can be directly judged according to the size relationship between the air-fuel ratio change cumulative parameter and the interval threshold of the parameter determination interval.

[0111] At this time, it can be first judged which type the current diagnosis type is. When the current diagnosis type is the rich-to-lean type, if the air-fuel ratio change cumulative parameter is greater than the interval maximum value in the parameter determination interval, it can be directly judged that the air-fuel ratio sensor of the vehicle does not have a response delay fault. If the air-fuel ratio change cumulative parameter is less than the interval minimum value in the parameter determination interval, it can be directly judged that the air-fuel ratio sensor of the vehicle has a response delay fault.

[0112] When the current diagnosis type is the lean-to-rich type, if the air-fuel ratio change cumulative parameter is greater than the interval maximum value in the parameter determination interval, it can be directly judged that the air-fuel ratio sensor of the vehicle has a response delay fault. If the air-fuel ratio change cumulative parameter is less than the interval minimum value in the parameter determination interval, it can be directly judged that the air-fuel ratio sensor of the vehicle does not have a response delay fault.

[0113] Further, when judging whether the vehicle supports the delay active diagnosis, the intake air amount, the intake air change amount, the rotation speed, the rotation speed change amount and / or the air-fuel ratio of the engine of the vehicle can be combined to make the judgment, and thus the step S12 in this embodiment can include:

[0114] If the air-fuel ratio change cumulative parameter is in the parameter judgment interval, the engine operation parameter of the vehicle is obtained.

[0115] It is detected whether the engine operation parameter is in a preset detection interval.

[0116] If it is in the preset detection interval, it is determined that the vehicle meets the active diagnosis enabling condition.

[0117] It should be noted that the engine operation parameter includes at least one of the intake air amount, the intake air change amount, the rotation speed, the rotation speed change amount and the air-fuel ratio of the engine of the vehicle. The management personnel of the diagnosis equipment can set different preset detection intervals for different types of engine operation parameters.

[0118] It can be understood that if the engine operation parameter is in the preset detection interval, it means that the vehicle currently supports the active diagnosis, and thus it can be determined that the vehicle meets the active diagnosis enabling condition.

[0119] Step S13: If the vehicle meets the active diagnosis enabling condition, it is determined that the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnosis type.

[0120] It can be understood that if the vehicle meets the active diagnosis enabling condition, it means that the vehicle can perform the active diagnosis at this time, and thus it can be determined that the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnosis type.

[0121] In this embodiment, the parameter judgment interval corresponding to the current diagnosis type is found, and if the air-fuel ratio change cumulative parameter is in the parameter judgment interval, it is detected whether the vehicle meets the active diagnosis enabling condition, and if the vehicle meets the active diagnosis enabling condition, it is determined that the air-fuel ratio change cumulative parameter meets the active diagnosis condition corresponding to the current diagnosis type. Since the air-fuel ratio change cumulative parameter is in the parameter judgment interval corresponding to the current diagnosis type, that is, it is judged that the vehicle needs to perform the active diagnosis, the state of the vehicle is also detected to support the active diagnosis, which ensures that the active diagnosis can be performed on the vehicle and also avoids the influence of the diagnosis on the normal operation of the vehicle.

[0122] In addition, the present embodiment also provides a storage medium, and the storage medium stores an air-fuel ratio sensor diagnosis program. When the air-fuel ratio sensor diagnosis program is executed by a processor, the steps of the air-fuel ratio sensor diagnosis method described above are implemented.

[0123] Referring to Figure 5 , Figure 5 is a structural block diagram of a first embodiment of the air-fuel ratio sensor diagnosis device of the present application.

[0124] As shown in Figure 5 , the air-fuel ratio sensor diagnosis device provided by the embodiment of the present application comprises:

[0125] a type determination module 10 configured to determine a current diagnosis type according to an air-fuel ratio change cumulative parameter of a vehicle when the vehicle is fuel-cut;

[0126] a delay diagnosis module 20 configured to control the vehicle to perform intrusive enrichment to determine an air-fuel ratio delay parameter if the air-fuel ratio change cumulative parameter meets an active diagnosis condition corresponding to the current diagnosis type;

[0127] a parameter calculation module 30 configured to calculate a current diagnosis parameter according to the air-fuel ratio delay parameter and a historical diagnosis parameter;

[0128] a fault judgment module 40 configured to determine whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnosis parameter if a total number of intrusive enrichment is greater than a preset number.

[0129] The embodiment determines a current diagnosis type according to an air-fuel ratio change cumulative parameter of a vehicle when the vehicle is fuel-cut, controls the vehicle to perform intrusive enrichment to determine an air-fuel ratio delay parameter if the air-fuel ratio change cumulative parameter meets an active diagnosis condition corresponding to the current diagnosis type, calculates a current diagnosis parameter according to the air-fuel ratio delay parameter and a historical diagnosis parameter, and determines whether the air-fuel ratio sensor of the vehicle has a response delay fault according to the current diagnosis parameter if a total number of intrusive enrichment is greater than a preset number. Since it is determined in advance according to the air-fuel ratio change cumulative parameter whether diagnosis is needed and the diagnosis type, unnecessary active diagnosis using intrusive enrichment is reduced as much as possible, and when active diagnosis is needed, fault judgment is performed by using the historical diagnosis parameter, so that the number of intrusive enrichment is reduced as much as possible, thereby reducing the impact of diagnosis on emissions.

[0130] Further, the type determination module 10 is further configured to acquire air-fuel ratio signals at intervals of a preset time length when the vehicle is fuel-cut, determine an air-fuel ratio change cumulative parameter according to the air-fuel ratio signals and a historical change cumulative parameter, and determine a current diagnosis type according to the air-fuel ratio change cumulative parameter when a calculation number reaches a preset number threshold.

[0131] Further, the type determination module 10 is further configured to detect whether an air-fuel ratio signal of an air-fuel ratio sensor is in a preset interval when the vehicle is fuel-cut, and acquire air-fuel ratio signals at intervals of a preset time length if the air-fuel ratio signal is in the preset interval.

[0132] Further, the type determining module 10 is further configured to determine an air-fuel ratio change amount according to the air-fuel ratio signal and a previously obtained air-fuel ratio signal; and perform weighted summation on the air-fuel ratio change amount and a historical change cumulative parameter according to a preset weighting coefficient, to obtain an air-fuel ratio change cumulative parameter.

[0133] Further, the delay diagnosis module 20 is further configured to search for a parameter determination interval corresponding to the current diagnosis type; if the air-fuel ratio change cumulative parameter is within the parameter determination interval, determine whether the vehicle satisfies an active diagnosis enabling condition; and if the vehicle satisfies the active diagnosis enabling condition, determine that the air-fuel ratio change cumulative parameter satisfies an active diagnosis condition corresponding to the current diagnosis type.

[0134] Further, the delay diagnosis module 20 is further configured to, if the air-fuel ratio change cumulative parameter is within the parameter determination interval, obtain an engine operating parameter of the vehicle, the engine operating parameter including at least one of an intake air amount, an intake air change amount, a rotation speed, a rotation speed change amount, and an air-fuel ratio of the vehicle engine; determine whether the engine operating parameter is within a preset detection interval; and if the engine operating parameter is within the preset detection interval, determine that the vehicle satisfies the active diagnosis enabling condition.

[0135] Further, the fault judging module 40 is further configured to, if the total number of invasive enrichment is greater than a preset number, search for a fault detection threshold value corresponding to the current diagnosis type; if the current diagnosis type is a rich-to-lean type and the current diagnosis parameter is less than the fault detection threshold value, determine that the air-fuel ratio sensor of the vehicle has a response delay fault; and if the current diagnosis type is a lean-to-rich type and the current diagnosis parameter is greater than the fault detection threshold value, determine that the air-fuel ratio sensor of the vehicle has a response delay fault.

[0136] It should be understood that the above is only an example, and does not constitute any limitation on the technical solutions of the present application. In specific applications, those skilled in the art can set up according to the needs, and the present application does not limit this.

[0137] It should be noted that the above-described workflow is only illustrative and does not limit the scope of protection of the present application. In actual applications, those skilled in the art can select part or all of them to achieve the purpose of the present embodiment, and this is not limited here.

[0138] In addition, technical details not described in detail in the present embodiment can be referred to the air-fuel ratio sensor diagnosis method provided by any embodiment of the present application, which will not be described here.

[0139] Moreover, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including" "comprising" or "having" and variations thereof herein is intended to encompass the presence of one or more recited elements or steps and not the exclusion of any other integers or steps. The use of "including", "comprising", "having" and "with" and variations thereof herein is intended to encompass the presence of one or more recited elements or steps and not the exclusion of any other integers or steps.

[0140] The above-mentioned embodiment numbers of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments.

[0141] Those skilled in the art can clearly understand the above-mentioned embodiment methods from the description of the above embodiments, which can be realized by software and necessary general hardware platforms, of course, can also be realized by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a read only memory (ROM) / RAM, a magnetic disk, an optical disk), and includes a plurality of instructions for making a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) execute the methods described in various embodiments of the present application.

[0142] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A diagnostic method for an air-fuel ratio sensor, characterized in that, The air-fuel ratio sensor diagnostic method includes the following steps: When the vehicle's fuel supply is cut off, the current diagnostic type is determined based on the cumulative parameters of the vehicle's air-fuel ratio change. If the cumulative air-fuel ratio change parameter satisfies the active diagnosis condition corresponding to the current diagnosis type, then the vehicle is controlled to perform invasive enrichment to determine the air-fuel ratio delay parameter. Calculate the current diagnostic parameters based on the air-fuel ratio delay parameters and historical diagnostic parameters; If the total number of invasive enrichment operations exceeds the preset number, then the air-fuel ratio sensor of the vehicle is determined to have a response delay fault based on the current diagnostic parameters. The cumulative air-fuel ratio change parameter is a quantitative parameter constructed based on the change in the air-fuel ratio of the vehicle within a preset time period, which is used to determine the specific diagnostic type and whether to perform delayed active diagnosis. The process of determining the current diagnostic type based on the cumulative parameters of the vehicle's air-fuel ratio change includes: When the vehicle's fuel is cut off, the air-fuel ratio signal is acquired at preset intervals. The change in air-fuel ratio is determined based on the air-fuel ratio signal and the previously acquired air-fuel ratio signal. The cumulative air-fuel ratio change parameter is obtained by weighting and summing the air-fuel ratio change and the historical cumulative change parameter according to the preset weighting coefficient using a preset weighting formula. When the number of calculations reaches a preset threshold, it is checked whether the cumulative parameter of air-fuel ratio change is a positive number; If the number is positive, the current diagnostic type is determined to be concentrated to diluted. If the number is not positive, the current diagnostic type is determined to be the thin to thick type; The calculation of the current diagnostic parameters based on the air-fuel ratio delay parameter and historical diagnostic parameters includes: The current diagnostic parameters are obtained by weighting and summing the air-fuel ratio delay parameter and historical diagnostic parameters according to the preset delay coefficient using the diagnostic parameter calculation formula.

2. The air-fuel ratio sensor diagnostic method as described in claim 1, characterized in that, The step of acquiring the air-fuel ratio signal at preset time intervals when the vehicle's fuel supply is cut off includes: When the vehicle's fuel is cut off, the air-fuel ratio signal from the air-fuel ratio sensor is checked to see if it is within a preset range. If the signal is within a preset range, the air-fuel ratio signal is obtained at preset time intervals.

3. The air-fuel ratio sensor diagnostic method as described in claim 1, characterized in that, Before the step of determining the air-fuel ratio delay parameter by controlling the vehicle to perform invasive enrichment if the cumulative air-fuel ratio change parameter meets the active diagnosis conditions corresponding to the current diagnosis type, the method further includes: Find the parameter determination range corresponding to the current diagnostic type; If the cumulative air-fuel ratio change parameter is within the parameter determination range, then it is detected whether the vehicle meets the active diagnostic activation conditions. If the vehicle meets the active diagnostic activation conditions, then the cumulative air-fuel ratio change parameter is determined to meet the active diagnostic conditions corresponding to the current diagnostic type.

4. The air-fuel ratio sensor diagnostic method as described in claim 3, characterized in that, The step of detecting whether the vehicle meets the active diagnostic activation conditions if the cumulative air-fuel ratio change parameter is within the parameter determination range includes: If the cumulative air-fuel ratio change parameter is within the parameter determination range, then the engine operating parameters of the vehicle are obtained. The engine operating parameters include at least one of the following: engine intake volume, intake change, engine speed, engine speed change, and air-fuel ratio. Detect whether the engine operating parameters are within a preset detection range; If the vehicle is within the preset detection range, it is determined that the active diagnostic activation conditions are met.

5. The air-fuel ratio sensor diagnostic method according to any one of claims 1-4, characterized in that, The step of determining whether the vehicle's air-fuel ratio sensor has a response delay fault based on the current diagnostic parameters if the total number of invasive enrichment operations exceeds a preset number includes: If the total number of invasive concentrations exceeds the preset number, then the fault detection threshold corresponding to the current diagnostic type is searched. When the current diagnostic type is rich to lean and the current diagnostic parameter is less than the fault detection threshold, it is determined that the vehicle's air-fuel ratio sensor has a response delay fault. When the current diagnostic type is lean to rich and the current diagnostic parameter is greater than the fault detection threshold, it is determined that the vehicle's air-fuel ratio sensor has a response delay fault.

6. An air-fuel ratio sensor diagnostic device, characterized in that, The air-fuel ratio sensor diagnostic device includes the following modules: The type determination module is used to determine the current diagnostic type based on the cumulative parameters of the vehicle's air-fuel ratio change when the vehicle's fuel supply is cut off. The delayed diagnosis module is used to control the vehicle to perform invasive enrichment and determine the air-fuel ratio delay parameter if the cumulative parameter of the air-fuel ratio change meets the active diagnosis condition corresponding to the current diagnosis type. The parameter calculation module is used to calculate the current diagnostic parameters based on the air-fuel ratio delay parameter and the historical diagnostic parameters; The fault diagnosis module is used to determine whether the air-fuel ratio sensor of the vehicle has a response delay fault based on the current diagnostic parameters if the total number of invasive enrichment operations is greater than a preset number. The cumulative air-fuel ratio change parameter is a quantitative parameter constructed based on the change in the air-fuel ratio of the vehicle within a preset time period. It is used to determine the specific diagnostic type and whether to perform delayed active diagnosis. The type determination module is further configured to acquire air-fuel ratio signals at preset time intervals when the vehicle's fuel is cut off; determine the air-fuel ratio change based on the air-fuel ratio signal and the previously acquired air-fuel ratio signal; obtain a cumulative air-fuel ratio change parameter by weighting the air-fuel ratio change and the historical cumulative change parameter using a preset parameter weighting formula and a preset weighting coefficient; and detect whether the cumulative air-fuel ratio change parameter is positive when the number of calculations reaches a preset threshold. If the number is positive, the current diagnostic type is determined to be concentrated to diluted. If the number is not positive, the current diagnostic type is determined to be the thin to thick type; The parameter calculation module is also used to obtain the current diagnostic parameters by weighted summing of the air-fuel ratio delay parameter and historical diagnostic parameters according to the preset delay coefficient using the diagnostic parameter calculation formula.

7. An air-fuel ratio sensor diagnostic device, characterized in that, The air-fuel ratio sensor diagnostic device includes: a processor, a memory, and an air-fuel ratio sensor diagnostic program stored in the memory and executable by the processor. When the air-fuel ratio sensor diagnostic program is executed, it implements the steps of the air-fuel ratio sensor diagnostic method as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores an air-fuel ratio sensor diagnostic program, which, when executed, implements the steps of the air-fuel ratio sensor diagnostic method as described in any one of claims 1-5.

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