Method for diagnosing slow response failure of rear oxygen sensor and related hardware

Abstract

The embodiment of the application provides a kind of post oxygen sensor slow response fault diagnosis method and related hardware, comprising: if according to engine operating state parameter determines that engine enters first working condition, simultaneously according to post oxygen sensor operating state parameter determines that post oxygen sensor is in preset operating state, the measured voltage value of post oxygen sensor is monitored;If in the duration of any second condition of engine, the numerical change range of measured voltage value meets the numerical change range requirement corresponding to second condition, then determine that the response range of post oxygen sensor belongs to normal state;If in the duration of second condition, the average change rate of measured voltage value is greater than the target change rate threshold value corresponding to second condition, then determine that the response speed of post oxygen sensor belongs to slow state;According to the second condition quantity that the response range of post oxygen sensor belongs to normal state and the response speed of post oxygen sensor belongs to slow state occur, it is judged whether post oxygen sensor is slow response fault.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automation detection technology, in particular to a post oxygen sensor slow response fault diagnosis method and related hardware. BACKGROUND

[0002] The post oxygen sensor, also known as the downstream oxygen sensor, is an oxygen sensor installed at the rear end of the three-way catalyst in the engine system, used to monitor the oxygen concentration in the exhaust gas after the three-way catalyst treatment. The post oxygen concentration measured by the post oxygen sensor has important reference significance for the electronic control unit (ECU) to monitor the working state of the three-way catalyst, engine misfire fault, engine lack of fire fault, etc. Therefore, during the engine operation, the normal working of the post oxygen sensor is crucial.

[0003] During the use of the post oxygen sensor, it may cause faults due to abnormal heating temperature, post oxygen concentration oscillation, etc., which is manifested as abnormal fluctuation of the measured voltage value of the post oxygen sensor, and the post oxygen sensor cannot quickly recover to the normal working state, i.e. slow response fault. In addition, other types of faults of the post oxygen sensor may also be manifested as abnormal measured voltage value. Therefore, how to diagnose the fault of the post oxygen sensor to accurately determine whether the post oxygen sensor has a slow response fault or other types of faults is a problem to be solved at present. SUMMARY

[0004] The present application provides a post oxygen sensor slow response fault diagnosis method and related hardware to provide a diagnosis scheme that can accurately determine whether the post oxygen sensor has a slow response fault.

[0005] The present application provides a post oxygen sensor slow response fault diagnosis method, comprising:

[0006] monitoring engine operating state parameters and post oxygen sensor working state parameters during engine operation;

[0007] if it is determined according to the engine operating state parameters that the engine enters a first working condition, and it is determined according to the post oxygen sensor working state parameters that the post oxygen sensor is in a preset working state, then the measured voltage value of the post oxygen sensor is monitored;

[0008] if the numerical value change range of the measured voltage value meets the numerical value change range requirement corresponding to the second working condition in the duration of any second working condition of the engine, then it is determined that the response range of the post oxygen sensor belongs to the normal state;

[0009] if the average rate of change of the measured voltage value during the duration of the second working condition is greater than a target rate of change threshold corresponding to the second working condition, it is determined that the response speed of the rear oxygen sensor is in a too slow state;

[0010] According to the number of second working conditions in which the response range of the rear oxygen sensor is in a normal state and the response speed of the rear oxygen sensor is in a too slow state, it is determined whether the rear oxygen sensor has a slow response fault.

[0011] Optionally, the engine operating state parameters include the current engine speed, an engine fuel supply state parameter, and an engine fault state parameter.

[0012] The determination of the engine entering a first working condition according to the engine operating state parameters comprises:

[0013] If the current engine speed is greater than a preset speed threshold, and it is determined according to the engine fuel supply state parameter that the engine is in an oil-off state, and it is determined according to the engine fault state parameter that the engine has no fault, it is determined that the engine enters a first working condition.

[0014] Optionally, the rear oxygen sensor operating state parameters include the temperature and the measured voltage value of the rear oxygen sensor.

[0015] The determination of the rear oxygen sensor being in a preset operating state according to the rear oxygen sensor operating state parameters comprises:

[0016] If the temperature of the rear oxygen sensor is greater than a preset temperature threshold, and the measured voltage value is greater than a preset voltage threshold, it is determined that the rear oxygen sensor is in a preset operating state.

[0017] Optionally, the engine is determined to be in a second working condition in the following manner:

[0018] According to the engine fuel supply state parameter, it is determined that the engine is in an oil-off state, and the duration of the oil-off state is greater than a target time threshold, it is determined that the engine is in a second working condition during the duration of the oil-off state.

[0019] Optionally, the target time threshold is determined in the following manner:

[0020] According to the preset correspondence between the air flow and the time threshold, the target time threshold is determined according to the air flow at the position of the rear oxygen sensor at the start of the second working condition;

[0021] Wherein, the greater the air flow, the greater the corresponding time threshold.

[0022] Optionally, whether the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second working condition of the engine in the duration of the second working condition of the engine is determined by the following method:

[0023] If the range of the measured voltage value is greater than the target range threshold corresponding to the second working condition and the measured voltage value is in the target voltage range corresponding to the second working condition in the duration of the second working condition, it is determined that the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second working condition.

[0024] Optionally, the target variation rate threshold corresponding to the second working condition is determined by the following method:

[0025] The target variation rate threshold is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition by using a preset corresponding relationship between air flow and variation rate threshold.

[0026] Wherein, the greater the air flow, the greater the corresponding variation rate threshold.

[0027] Based on the same inventive concept, the embodiments of the present application also provide a rear oxygen sensor slow response fault diagnosis device, comprising:

[0028] The diagnosis triggering module is configured to monitor engine operating state parameters and rear oxygen sensor working state parameters during engine operation; if it is determined that the engine enters a first working condition according to the engine operating state parameters, and the rear oxygen sensor is in a preset working state according to the rear oxygen sensor working state parameters, the measured voltage value of the rear oxygen sensor is monitored.

[0029] The first diagnosis module is configured to determine that the response range of the rear oxygen sensor belongs to a normal state if the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second working condition in the duration of any second working condition of the engine.

[0030] The second diagnosis module is configured to determine that the response speed of the rear oxygen sensor belongs to a too slow state if the average variation rate of the measured voltage value is greater than the target variation rate threshold corresponding to the second working condition in the duration of the second working condition.

[0031] The third diagnosis module is configured to determine whether the rear oxygen sensor has a slow response fault according to the number of second working conditions in which the response range of the rear oxygen sensor belongs to a normal state and the response speed of the rear oxygen sensor belongs to a too slow state.

[0032] Based on the same inventive concept, the embodiments of the present application also provide an electronic device, comprising: a processor and a memory for storing instructions executable by the processor.

[0033] The processor is configured to execute the instructions to implement the post-oxygen sensor slow response fault diagnosis method.

[0034] Based on the same inventive concept, the present application also provides a computer readable storage medium storing computer program codes, which, when executed on a computer, cause the computer to execute the post-oxygen sensor slow response fault diagnosis method.

[0035] Based on the same inventive concept, the present application also provides a computer program product, which comprises computer program codes, which, when executed on a computer, cause the computer to execute the post-oxygen sensor slow response fault diagnosis method.

[0036] The present application has the following advantages:

[0037] The post-oxygen sensor slow response fault diagnosis method provided by the present application can exclude the non-response and random response fault types of the post-oxygen sensor by determining whether the response range of the post-oxygen sensor is normal according to the change range of the voltage measurement value of the post-oxygen sensor when the engine is in a required fuel cut-off working condition, and then determining whether the response speed of the post-oxygen sensor is too slow according to whether the change rate of the voltage measurement value of the post-oxygen sensor is greater than the change threshold matched with the current working condition. Finally, whether the post-oxygen sensor has a slow response fault is determined according to the number of times that the response range of the post-oxygen sensor is normal but the response speed is too slow, so that misjudgment caused by accidental errors can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The flowchart of the post-oxygen sensor slow response fault diagnosis method provided by the present application;

[0039] Figure 2 The structural schematic diagram of the post-oxygen sensor slow response fault diagnosis device provided by the present application;

[0040] Figure 3 The structural schematic diagram of the electronic device provided by the present application. DETAILED DESCRIPTION

[0041] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the present application will be further described below in conjunction with the accompanying drawings and embodiments. However, the example embodiments can be implemented in various forms, and should not be understood as being limited to the embodiments set forth herein; on the contrary, these embodiments are provided so as to make the present application more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art. Identical reference numerals in the drawings represent identical or similar structures, and thus repeated description thereof will be omitted. The words expressing position and direction described in the present application are described with reference to the drawings, but can be changed as needed, and the changes made are included in the scope of protection of the present application. The drawings of the present application are only used to illustrate the relative positional relationship and do not represent the true proportions.

[0042] It should be noted that specific details are set forth in the following description in order to provide a thorough understanding of the present application. However, the present application can be practiced in a variety of ways beyond those described herein, and those skilled in the art can make similar substitutions without departing from the scope of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below. The subsequent description of the specification is a preferred embodiment for implementing the present application, and is intended to illustrate the general principles of the present application, rather than to limit the scope of the present application. The scope of protection of the present application is defined by the appended claims.

[0043] The post-oxygen sensor slow response fault diagnosis method and related hardware provided by the embodiments of the present application will be specifically described below in conjunction with the accompanying drawings.

[0044] The embodiments of the present application provide a post-oxygen sensor slow response fault diagnosis method, as shown in Figure 1 The method comprises the following steps.

[0045] S101, monitoring engine operating state parameters and post-oxygen sensor state parameters during engine operation.

[0046] In the specific implementation process, the engine operating state parameters at least include engine oil supply state parameters. Optionally, the engine operating state parameters include: engine oil supply state parameters, engine current speed, and engine fault state parameters.

[0047] In the specific implementation process, the working state parameters of the post-oxygen sensor at least include the working temperature of the post-oxygen sensor. Optionally, the working state parameters of the post-oxygen sensor include the working temperature of the post-oxygen sensor and the measured voltage value.

[0048] S102, judging whether the engine enters a first working condition according to the engine operating state parameters, and judging whether the post-oxygen sensor is in a preset working state according to the working state parameters of the post-oxygen sensor.

[0049] If the results of the step S102 are all yes, then the step S103 is performed; otherwise, the step S101 is returned.

[0050] Optionally, if the engine operating state parameters comprise: an engine oil supply state parameter, an engine current speed, and an engine fault state parameter, then the engine entering the first working condition is determined according to the engine operating state parameters in the following manner:

[0051] If the engine current speed is greater than a preset speed threshold value, and the engine is determined to be in an oil-off state according to the engine oil supply state parameter, and the engine is determined to be fault-free according to the engine fault state parameter, then the engine is determined to enter the first working condition.

[0052] Similarly, if the engine operating state parameters omit some parameters compared with the above embodiment, then corresponding steps can also be omitted in the process of determining whether the engine enters the first working condition, which will not be described here.

[0053] Specifically, the working state parameters of the rear oxygen sensor comprise a working temperature and a measured voltage value of the rear oxygen sensor, and the rear oxygen sensor is determined to be in the preset working state according to the working state parameters of the rear oxygen sensor in the following manner:

[0054] If the temperature of the rear oxygen sensor is greater than a preset temperature threshold value, and the measured voltage value is greater than a preset voltage threshold value, then the rear oxygen sensor is determined to be in the preset working state.

[0055] Similarly, if the working state parameters of the rear oxygen sensor omit the measured voltage value compared with the above embodiment, then corresponding steps can also be omitted in the process of determining whether the rear oxygen sensor is in the preset working state, which will not be described here.

[0056] S103, the measured voltage value of the rear oxygen sensor is monitored.

[0057] S104, it is determined whether the engine is in a second working condition.

[0058] In the specific implementation process, whether the engine is in the second working condition is determined in the following manner:

[0059] If the engine is determined to be in an oil-off state according to the engine oil supply state parameter, and the duration of the oil-off state is greater than a target time threshold value, then the engine is determined to be in the second working condition during the duration of the oil-off state.

[0060] As an optional embodiment, the target time threshold value is a preset time threshold value.

[0061] As another optional embodiment, the target time threshold value is determined in the following manner:

[0062] The target time threshold is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition by using a preset corresponding relationship between the air flow and the target time threshold. The greater the air flow, the greater the corresponding time threshold.

[0063] In this way, it can be determined whether to perform subsequent diagnosis of the slow response fault of the rear oxygen sensor according to the fuel cut state of the engine, so that adaptive diagnosis can be performed for different second working conditions, and the generality of the scheme is improved.

[0064] If the result of step S104 is yes, step S105 is performed; if the result of step S104 is no, the step S101 is returned.

[0065] S105, determine whether the numerical range of the measured voltage value in the duration of the second working condition meets the numerical range requirement corresponding to the second working condition.

[0066] Specifically, whether the numerical range of the measured voltage value in the duration of the second working condition meets the numerical range requirement corresponding to the second working condition is determined by the following method:

[0067] If the range of the measured voltage value in the duration of the second working condition is greater than the target range threshold corresponding to the second working condition, and the measured voltage value is in the target voltage range corresponding to the second working condition (i.e. the measured voltage value is always not greater than the upper limit of the target voltage range and not less than the lower limit of the target voltage range in the duration of the second working condition), it is determined that the numerical range of the measured voltage value meets the numerical range requirement corresponding to the second working condition.

[0068] As an optional embodiment, the target range threshold corresponding to different second working conditions is the same preset range threshold.

[0069] As another optional embodiment, the target range threshold is determined by the following method:

[0070] The target range threshold is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition by using a preset corresponding relationship between the air flow and the target range threshold. The greater the air flow, the greater the corresponding range threshold.

[0071] As an optional embodiment, the target voltage range corresponding to different second working conditions is the same preset voltage range.

[0072] As another optional embodiment, the target voltage range is determined by the following method:

[0073] The target voltage range is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition, by using a preset corresponding relationship between air flow and voltage range. The greater the air flow, the greater the upper limit of the corresponding voltage range.

[0074] In this way, the target range threshold / target voltage range is determined according to the air flow at the position of the rear oxygen sensor, so that adaptive diagnosis can be performed for different second working conditions, and the generality of the scheme is improved.

[0075] If the result of step S105 is yes, step S106 is performed; if the result of step S105 is no, step S101 is returned.

[0076] S106, determining whether the response range of the rear oxygen sensor in the duration of the second working condition belongs to a normal state.

[0077] S107, determining whether the average change rate of the measured voltage value in the duration of the second working condition is greater than a target change rate threshold corresponding to the second working condition.

[0078] In the technical scheme of the embodiment of the application, the average change rate of the measured voltage value △ V is calculated in the following way:

[0079]

[0080] V2 is the measured voltage value corresponding to the end time of the second working condition, and V1 is the measured voltage value corresponding to the beginning time of the second working condition. Generally, since the engine gradually reduces the exhaust volume after fuel cut, the measured voltage value of the rear oxygen sensor gradually decreases, △ V is usually negative.

[0081] Further optionally, the target change rate threshold is determined in the following way:

[0082] The target change rate threshold is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition, by using a preset corresponding relationship between air flow and change rate threshold. The greater the air flow, the greater the corresponding change rate threshold.

[0083] In this way, the target change rate threshold of the air flow at the position of the rear oxygen sensor is used, so that adaptive diagnosis can be performed for different second working conditions, and the generality of the scheme is improved.

[0084] If the result of step S107 is yes, step S108 is performed; if the result of step S107 is no, step S101 is returned.

[0085] S108, determining whether the response speed of the rear oxygen sensor belongs to the too slow state in the duration of the second working condition.

[0086] S109, determining whether the slow response fault of the rear oxygen sensor occurs according to the number of the second working conditions in which the response range of the rear oxygen sensor belongs to the normal state and the response speed of the rear oxygen sensor belongs to the too slow state.

[0087] If the result of the step S109 is yes, the step S110 is executed; if the result of the step S109 is no, the step S101 is returned.

[0088] As an optional embodiment, the step S109 of determining whether the slow response fault of the rear oxygen sensor occurs according to the number of the second working conditions in which the response range of the rear oxygen sensor belongs to the normal state and the response speed of the rear oxygen sensor belongs to the too slow state specifically includes:

[0089] determining whether the first number of the second working conditions in which the response range of the rear oxygen sensor belongs to the normal state and the response speed of the rear oxygen sensor belongs to the too slow state is greater than a preset alarm number threshold value within a preset time length; if the first number is greater than the preset alarm number threshold value, it is determined that the slow response fault of the rear oxygen sensor occurs.

[0090] For example, the preset time length is 2 hours. Within the 2 hours, the engine enters a total of 12 second working conditions in which the response range of the rear oxygen sensor belongs to the normal state and the response speed of the rear oxygen sensor belongs to the too slow state. If the preset alarm number threshold value is 10, it is determined that the slow response fault of the rear oxygen sensor occurs.

[0091] As another optional embodiment, the step S109 of determining whether the slow response fault of the rear oxygen sensor occurs according to the number of the second working conditions in which the response range of the rear oxygen sensor belongs to the normal state and the response speed of the rear oxygen sensor belongs to the too slow state specifically includes:

[0092] determining a third number of the second working conditions in which the response speed of the rear oxygen sensor belongs to the too slow state in the second number of the second working conditions in which the response range of the rear oxygen sensor belongs to the normal state according to time from rear to front; determining whether a ratio of the third number to the second number is greater than a preset alarm proportion threshold value; if the ratio is greater than the preset alarm proportion threshold value, it is determined that the slow response fault of the rear oxygen sensor occurs. The second number is not greater than a preset statistical number threshold value.

[0093] For example, a preset statistical quantity threshold is set as 5. The engine enters 12 second working conditions in which the response range of the post-oxygen sensor is in the normal state. In the last 5 second working conditions in which the response range of the post-oxygen sensor is in the normal state, the response speed of the post-oxygen sensor in 4 second working conditions is in the too slow state. If a preset alarm proportion threshold is 60%, it is determined that the post-oxygen sensor has a slow response fault.

[0094] As another optional implementation, the step S109 of determining whether the post-oxygen sensor has a slow response fault according to the number of the second working conditions in which the response range of the post-oxygen sensor is in the normal state and the response speed of the post-oxygen sensor is in the too slow state specifically includes:

[0095] A fourth number of the second working conditions in which the response range of the post-oxygen sensor is in the normal state and a fifth number of the second working conditions in which the response range of the post-oxygen sensor is in the normal state and the response speed of the post-oxygen sensor is in the too slow state are determined after the engine is started. It is determined whether a ratio of the fifth number to the fourth number is greater than a preset alarm proportion threshold. If the ratio is greater than the preset alarm proportion threshold, it is determined that the post-oxygen sensor has a slow response fault.

[0096] For example, after the engine is started, the engine enters 12 second working conditions in which the response range of the post-oxygen sensor is in the normal state, and the engine enters 10 second working conditions in which the response speed of the post-oxygen sensor is in the too slow state. If a preset alarm proportion threshold is 60%, it is determined that the post-oxygen sensor has a slow response fault.

[0097] S110, determining that the post-oxygen sensor has a slow response fault and performing an alarm.

[0098] In the implementation process, the alarm can be performed by lighting a fault lamp, sounding an alarm prompt sound through a loudspeaker, popping up an alarm prompt information on a vehicle machine interface, and the like. The embodiments of the present application do not make too many limitations here.

[0099] The method for diagnosing a rear oxygen sensor slow response fault, provided by an embodiment of the present invention, eliminates possible rear oxygen sensor fault types such as no response or random response based on the variation range of the rear oxygen sensor voltage measurement value during a fuel-cut operation that meets the requirements. After determining that the rear oxygen sensor response range is normal, the method determines whether the rear oxygen sensor response speed is excessively slow based on whether the rate of change of the rear oxygen sensor voltage measurement value exceeds a variation threshold that matches the current operating conditions. Finally, the method determines whether the rear oxygen sensor has a slow response fault based on the number of times the rear oxygen sensor response range is normal but the response speed is excessively slow, thereby avoiding misdiagnosis caused by accidental errors. Furthermore, by triggering the rear oxygen sensor slow response diagnosis process after determining that the engine is in a condition that meets the rear oxygen sensor diagnosis criteria based on engine operating parameters and that the rear oxygen sensor is in a preset operating state based on rear oxygen sensor parameters during engine operation, the method enables the rear oxygen sensor slow response diagnosis to be performed without affecting vehicle driving, thereby preventing the impact of engine power fluctuations caused by active fuel cuts on vehicle power and ride quality, and preventing disruption to normal vehicle driving.

[0100] Based on the same inventive concept, the embodiment of the present invention also provides a rear oxygen sensor slow response fault diagnosis device, such as Figure 2 Shown, including:

[0101] a diagnostic trigger module M1 for monitoring engine operating state parameters and rear oxygen sensor operating state parameters during engine operation; and monitoring a measured voltage value of the rear oxygen sensor if the engine is determined to have entered a first operating condition based on the engine operating state parameters and the rear oxygen sensor is determined to be in a preset operating state based on the rear oxygen sensor operating state parameters;

[0102] a first diagnostic module M2, configured to determine that the response range of the rear oxygen sensor is normal if, during the duration of any second operating condition of the engine, the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition;

[0103] a second diagnostic module M3, configured to determine that a response speed of the rear oxygen sensor is too slow if, during the duration of the second operating condition, an average change rate of the measured voltage value is greater than a target change rate threshold corresponding to the second operating condition;

[0104] The third diagnostic module M4 is configured to determine whether a slow response fault occurs in the rear oxygen sensor according to the number of second operating conditions in which the response range of the rear oxygen sensor is normal and the response speed of the rear oxygen sensor is too slow.

[0105] Optionally, the engine operating state parameter comprises an engine current rotating speed, an engine oil supply state parameter and an engine fault state parameter.

[0106] The determining of the engine entering the first working condition according to the engine operating state parameter comprises:

[0107] If the engine current rotating speed is greater than a preset rotating speed threshold, the engine is determined to be in an oil-off state according to the engine oil supply state parameter, and the engine is determined to be fault-free according to the engine fault state parameter, the engine is determined to enter the first working condition.

[0108] Optionally, the rear oxygen sensor working state parameter comprises a temperature and a measured voltage value of the rear oxygen sensor.

[0109] The determining of the rear oxygen sensor being in the preset working state according to the rear oxygen sensor working state parameter comprises:

[0110] If the temperature of the rear oxygen sensor is greater than a preset temperature threshold, and the measured voltage value is greater than a preset voltage threshold, the rear oxygen sensor is determined to be in the preset working state.

[0111] Optionally, the engine is determined to be in the second working condition by:

[0112] If the engine is determined to be in an oil-off state according to the engine oil supply state parameter, and a duration of the oil-off state is greater than a target time threshold, the engine is determined to be in the second working condition in the duration of the oil-off state.

[0113] Optionally, the target time threshold is determined by:

[0114] According to an air flow at a position of the rear oxygen sensor at a start time of the second working condition, the target time threshold is determined by using a preset corresponding relationship between the air flow and the time threshold.

[0115] Wherein, the greater the air flow is, the greater the corresponding time threshold is.

[0116] Optionally, whether a numerical value variation range of the measured voltage value meets a numerical value variation range requirement corresponding to the second working condition is determined by:

[0117] If a range of the measured voltage value is greater than a target range threshold corresponding to the second working condition in the duration of the second working condition, and the measured voltage value is in a target voltage range corresponding to the second working condition, it is determined that the numerical value variation range of the measured voltage value meets the numerical value variation range requirement corresponding to the second working condition.

[0118] Optionally, the target difference threshold corresponding to the second working condition is determined by the following way:

[0119] The target difference threshold is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition by using a preset corresponding relationship between air flow and difference threshold. The greater the air flow, the greater the corresponding difference threshold.

[0120] Optionally, the target voltage range corresponding to the second working condition is determined by the following way:

[0121] The target voltage range is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition by using a preset corresponding relationship between air flow and voltage range. The greater the air flow, the greater the upper limit of the corresponding voltage range.

[0122] Optionally, the target change rate threshold corresponding to the second working condition is determined by the following way:

[0123] The target change rate threshold is determined according to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition by using a preset corresponding relationship between air flow and change rate threshold.

[0124] The greater the air flow, the greater the corresponding change rate threshold.

[0125] Optionally, the number of the second working conditions in which the response range of the rear oxygen sensor is in the normal state and the response speed of the rear oxygen sensor is in the too slow state is used to determine whether the rear oxygen sensor has a slow response fault, and specifically includes:

[0126] A fourth number of the second working conditions in which the response range of the rear oxygen sensor is in the normal state and a fifth number of the second working conditions in which the response speed of the rear oxygen sensor is in the too slow state are determined after the engine is started. It is determined whether the ratio of the fifth number to the fourth number is greater than a preset alarm proportion threshold. If the ratio is greater than the preset alarm proportion threshold, it is determined that the rear oxygen sensor has a slow response fault.

[0127] It should be understood that the embodiment of the rear oxygen sensor slow response fault diagnosis device described above is merely illustrative. For example, the division of the modules is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple modules may be combined or integrated into another system, or some features may be ignored or not executed. The functional modules in the embodiment may be integrated into a processing module, or may be physically present as individual unit modules, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional units. If the integrated unit is implemented in the form of a software functional module and sold or used as an independent product, it may be stored in a computer-readable storage medium.

[0128] Since the principle of solving the problem of the rear oxygen sensor slow response fault diagnosis device is basically the same as that of the rear oxygen sensor slow response fault diagnosis method, the implementation of the rear oxygen sensor slow response fault diagnosis device can refer to the implementation of the rear oxygen sensor slow response fault diagnosis method, which is not repeated here.

[0129] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, such as Figure 3 As shown, it includes: a processor 110 and a memory 120 for storing executable instructions of the processor 110;

[0130] The processor 110 is configured to execute the instructions to implement the rear oxygen sensor slow response fault diagnosis method.

[0131] In a specific implementation, the device may have relatively large differences due to different configurations or performances, and may include one or more processors 110, a memory 120, and a computer-readable storage medium 130. The memory 120 and / or the computer-readable storage medium 130 may include one or more applications 131 or data 132. The memory 120 and / or the computer-readable storage medium 130 may also include one or more operating systems 133, such as Windows, Mac OS, Linux, IOS, Android, Unix, FreeBSD, etc. The memory 120 and the computer-readable storage medium 130 may be temporary storage or persistent storage. The application 131 may include one or more modules ( Figure 3 (not shown), each module may include a series of instruction operations. Furthermore, the processor 110 may be configured to communicate with the computer-readable storage medium 130 and execute a series of instruction operations in the computer-readable storage medium 130 on the device. The device may also include one or more power supplies ( Figure 3one or more network interfaces 140, including a wired network interface 141 and / or a wireless network interface 142; one or more input / output interfaces 143.

[0132] Based on the same inventive concept, the embodiments of the present application further provide a computer readable storage medium, which stores a computer program, and when the computer program code is run on a computer, the computer is caused to execute the method for diagnosing slow response failure of a post oxygen sensor.

[0133] The readable storage medium can be any available medium that can be used to store by a computer or a data storage device such as a server, data center, etc. integrated with one or more available medium sets. The available medium can be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a high-density digital video disc (Digital Video Disc, DVD), a video compact disc (Video Compact Disc; VCD)), or a semiconductor medium (such as a solid state disk (Solid State Disk, SSD)), etc.

[0134] Since the above readable storage medium solves the problem by the same principle as the method for diagnosing slow response failure of a post oxygen sensor, the implementation of the above readable storage medium can refer to the implementation of the method, and the repeated parts will not be described again.

[0135] Based on the same inventive concept, the embodiments of the present application further provide a computer program product, which includes: computer program code, and when the computer program code is run on a computer, the computer is caused to execute the method for diagnosing slow response failure of a post oxygen sensor.

[0136] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a readable storage medium or transmitted from one readable storage medium to another readable storage medium, for example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode.

[0137] Since the problem-solving principle of the above computer program product is consistent with the post-oxygen sensor slow response fault diagnosis method, the implementation of the above computer program product can be referred to the implementation of the method, and the repeated parts will not be described.

[0138] Those skilled in the art will appreciate that embodiments of the application can be provided as methods, systems, or computer program products. Accordingly, the application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the application can be embodied in the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0139] The application is described with reference to flowcharts and / or block diagrams that illustrate the methods, apparatus (systems), and computer program products according to the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions that are executed by the processor of the computer or other programmable data processing apparatus generate an apparatus that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0140] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0141] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0142] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method of diagnosing a slow response failure of an exhaust gas oxygen sensor, characterized by, The method comprises: monitoring engine operating state parameters and rear oxygen sensor working state parameters during engine operation; if it is determined according to the engine operating state parameters that the engine enters a first working condition, and it is determined according to the rear oxygen sensor working state parameters that the rear oxygen sensor is in a preset working state, then monitoring the measured voltage value of the rear oxygen sensor; if the numerical value variation range of the measured voltage value meets the numerical value variation range requirement corresponding to the second working condition in the duration of any second working condition of the engine, then determining that the response range of the rear oxygen sensor belongs to a normal state; if the average change rate of the measured voltage value is greater than the target change rate threshold corresponding to the second working condition in the duration of the second working condition, then determining that the response speed of the rear oxygen sensor belongs to a too slow state; judging whether the rear oxygen sensor has a slow response fault according to the number of second working conditions in which the response range of the rear oxygen sensor belongs to a normal state and the response speed of the rear oxygen sensor belongs to a too slow state.

2. The method of claim 1, wherein, The engine operating state parameters comprise the current engine speed, engine oil supply state parameters and engine fault state parameters; The determination that the engine enters a first working condition according to the engine operating state parameters comprises: if the current engine speed is greater than a preset speed threshold, and it is determined according to the engine oil supply state parameters that the engine is in an oil-off state, and it is determined according to the engine fault state parameters that the engine has no fault, then determining that the engine enters a first working condition; The rear oxygen sensor working state parameters comprise the temperature and measured voltage value of the rear oxygen sensor; The determination that the rear oxygen sensor is in a preset working state according to the rear oxygen sensor working state parameters comprises: if the temperature of the rear oxygen sensor is greater than a preset temperature threshold, and the measured voltage value is greater than a preset voltage threshold, then determining that the rear oxygen sensor is in a preset working state.

3. The method of claim 1, wherein, The engine is determined to be in a second working condition in the following manner: if it is determined according to the engine oil supply state parameters that the engine is in an oil-off state, and the duration of the oil-off state is greater than a target time threshold, then determining that the engine is in a second working condition in the duration of the oil-off state.

4. The method of claim 3, wherein, The target time threshold is determined in the following manner: the target time threshold is determined according to the air flow at the position of the rear oxygen sensor at the start of the second working condition by using a preset corresponding relationship between air flow and time threshold; wherein the greater the air flow, the greater the corresponding time threshold.

5. The method of claim 1, wherein, The determination of whether the numerical value variation range of the measured voltage value meets the numerical value variation range requirement corresponding to the second working condition in the duration of the second working condition of the engine is made in the following manner: if the range of the measured voltage value is greater than the target range threshold corresponding to the second working condition, and the measured voltage value is in the target voltage range corresponding to the second working condition in the duration of the second working condition, then determining that the numerical value variation range of the measured voltage value meets the numerical value variation range requirement corresponding to the second working condition.

6. The method of claim 1, wherein, The target change rate threshold corresponding to the second working condition is determined in the following manner: According to the air flow at the position of the rear oxygen sensor at the beginning of the second working condition, the target change rate threshold is determined by using a preset corresponding relationship between the air flow and the change rate threshold; The greater the air flow, the greater the corresponding change rate threshold.

7. A rear oxygen sensor slow response fault diagnosis device, characterized in that: The method comprises the following steps: A diagnosis triggering module is configured to monitor engine operating state parameters and rear oxygen sensor working state parameters during engine operation; If it is determined that the engine enters a first working condition according to the engine operating state parameters and that the rear oxygen sensor is in a preset working state according to the rear oxygen sensor working state parameters, the measured voltage value of the rear oxygen sensor is monitored; A first diagnosis module is configured to determine that the response range of the rear oxygen sensor is in a normal state if, during the duration of any second working condition of the engine, the numerical change range of the measured voltage value meets the numerical change range requirement corresponding to the second working condition; A second diagnosis module is configured to determine that the response speed of the rear oxygen sensor is in a too slow state if, during the duration of the second working condition, the average change rate of the measured voltage value is greater than the target change rate threshold corresponding to the second working condition; A third diagnosis module is configured to determine whether the rear oxygen sensor has a slow response fault according to the number of second working conditions in which the response range of the rear oxygen sensor is in a normal state and the response speed of the rear oxygen sensor is in a too slow state.

8. An electronic device, comprising: The method comprises the following steps: A processor and a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the rear oxygen sensor slow response fault diagnosis method according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer program code, which, when executed on a computer, causes the computer to perform the rear oxygen sensor slow response fault diagnosis method according to any one of claims 1-6.

10. A computer program product, characterised in that, The computer program product comprises computer program code, which, when executed on a computer, causes the computer to perform the rear oxygen sensor slow response fault diagnosis method according to any one of claims 1-6.

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