Rear oxygen sensor slow response fault diagnosis method and related hardware

Abstract

The embodiment of the invention provides a post-oxygen sensor slow response fault diagnosis method and related hardware, and the method comprises the steps: determining that an engine enters a first working condition according to the operation state parameters of the engine, and determining that a post-oxygen sensor is in a preset working state according to the working state parameters of the post-oxygen sensor; if so, monitoring the measured voltage value of the rear oxygen sensor; if the value change range of the measured voltage value meets the value change range requirement corresponding to the second working condition in the duration of any second working condition of the engine, 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 a target change rate threshold value corresponding to the second working condition in the duration of the second working condition, determining that the response speed of the rear oxygen sensor belongs to an over-slow state; and according to the number of the 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 an over-slow state, judging whether the rear oxygen sensor has a slow response fault or not.

Description

Technical Field

[0001] The invention relates to the field of automated detection technology, and in particular to a method for diagnosing a slow response fault of a rear oxygen sensor and related hardware. Background Art

[0002] The rear oxygen sensor, also known as the downstream oxygen sensor, is an oxygen sensor installed at the rear end of the three-way catalytic converter in the engine system. It is used to monitor the oxygen concentration in the exhaust gas after the three-way catalytic converter is processed. The rear oxygen concentration measured by the rear oxygen sensor is of great reference significance for the Electronic Control Unit (ECU) to monitor the working status of the three-way catalytic converter, engine misfire faults, engine misfire faults, etc. Therefore, the normal operation of the rear oxygen sensor is very important during the operation of the engine.

[0003] During use, the rear oxygen sensor may fail due to abnormal heating temperature, rear oxygen concentration fluctuations and other factors, which is manifested as abnormal fluctuations in the measured voltage value of the rear oxygen sensor and the inability to quickly recover to a normal working state, i.e., a slow response failure. In addition, other types of rear oxygen sensor failures may also manifest as abnormal measured voltage values. Therefore, how to diagnose the rear oxygen sensor failure to accurately determine whether the rear oxygen sensor has a slow response failure rather than other types of failures is a problem that needs to be solved urgently. Summary of the invention

[0004] The embodiment of the present invention provides a method for diagnosing a slow response fault of a rear oxygen sensor and related hardware, so as to provide a diagnostic solution that can accurately determine whether a slow response fault occurs in the rear oxygen sensor.

[0005] An embodiment of the present invention provides a method for diagnosing a slow response fault of a rear oxygen sensor, comprising:

[0006] Monitor engine operating state parameters and rear oxygen sensor working state parameters during engine operation;

[0007] If it is determined according to the engine operating state parameter that the engine enters the first operating condition, and it is determined according to the rear oxygen sensor operating state parameter that the rear oxygen sensor is in a preset operating state, monitoring the measured voltage value of the rear oxygen sensor;

[0008] 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, it is determined that the response range of the rear oxygen sensor belongs to a normal state;

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

[0010] Whether a slow response fault occurs in the rear oxygen sensor is determined according to the number of second operating 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 an excessively slow state.

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

[0012] The step of determining that the engine enters the first operating condition according to the engine operating state parameter comprises:

[0013] If the current engine speed is greater than a preset speed threshold, and the engine is determined to be in a fuel cut-off state according to the engine fuel 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 operating condition.

[0014] Optionally, the rear oxygen sensor working state parameter includes a temperature and a measured voltage value of the rear oxygen sensor;

[0015] The determining, according to the rear oxygen sensor working state parameter, that the rear oxygen sensor is in a preset working state includes:

[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 working state.

[0017] Optionally, determining that the engine is in the second operating condition is performed in the following manner:

[0018] If it is determined according to the engine fuel supply state parameter that the engine is in a fuel cut-off state and the duration of the fuel cut-off state is greater than a target time threshold, it is determined that the engine is in a second operating condition during the duration of the fuel cut-off state.

[0019] Optionally, the target time threshold is determined by:

[0020] Determining the target time threshold according to the air flow at the position of the rear oxygen sensor when the second operating condition starts, using a preset correspondence between the air flow and the time threshold;

[0021] Among them, the larger the air flow rate, the larger the corresponding time threshold.

[0022] Optionally, it is determined whether the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition during the duration of the second operating condition of the engine by:

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

[0024] Optionally, the target change rate threshold corresponding to the second operating condition is determined by:

[0025] Determining the target change rate threshold value according to the air flow at the position of the rear oxygen sensor when the second operating condition starts, using a preset correspondence relationship between the air flow and the change rate threshold value;

[0026] Among them, the larger the air flow rate, the larger the corresponding change rate threshold.

[0027] Based on the same inventive concept, an embodiment of the present invention further provides a rear oxygen sensor slow response fault diagnosis device, comprising:

[0028] a diagnostic trigger module, used for monitoring engine operation state parameters and rear oxygen sensor working state parameters during engine operation; if it is determined that the engine enters the first operating condition according to the engine operation state parameters, and it is determined that the rear oxygen sensor is in a preset working state according to the rear oxygen sensor working state parameters, then monitoring the measured voltage value of the rear oxygen sensor;

[0029] a first diagnostic module, configured to determine that the response range of the rear oxygen sensor is in a normal state 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;

[0030] a second diagnostic module, configured to determine that a response speed of the rear oxygen sensor is in an overly slow state 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;

[0031] The third diagnostic module is used 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state.

[0032] Based on the same inventive concept, an embodiment of the present invention further provides 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 rear oxygen sensor slow response fault diagnosis method.

[0034] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program code. When the computer program code runs on a computer, the computer executes the rear oxygen sensor slow response fault diagnosis method.

[0035] Based on the same inventive concept, an embodiment of the present invention further provides a computer program product, which includes: computer program code, when the computer program code is run on a computer, the computer executes the rear oxygen sensor slow response fault diagnosis method.

[0036] The beneficial effects of the present invention are as follows:

[0037] The method for diagnosing a rear oxygen sensor slow response fault provided by an embodiment of the present invention eliminates possible fault types such as no response and random response of the rear oxygen sensor according to the change range of the voltage measurement value of the rear oxygen sensor when the engine is in a fuel cut-off condition that meets the requirements, and after determining that the response range of the rear oxygen sensor belongs to a normal state, determines whether the response speed of the rear oxygen sensor belongs to a too slow state according to whether the change rate of the voltage measurement value of the rear oxygen sensor is greater than the change amount threshold matching the current working condition. Finally, it is finally determined whether the rear oxygen sensor has a slow response fault according to the number of times the response range of the rear oxygen sensor belongs to a normal state but the response speed belongs to a too slow state, thereby avoiding misjudgment caused by accidental errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flowchart of a method for diagnosing a slow response fault of a rear oxygen sensor provided by an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the structure of a rear oxygen sensor slow response fault diagnosis device provided by an embodiment of the present invention;

[0040] Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and examples. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportions.

[0042] It should be noted that specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application and is not intended to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0043] The following specifically describes the rear oxygen sensor slow response fault diagnosis method and related hardware provided by the embodiment of the present invention in conjunction with the accompanying drawings.

[0044] The embodiment of the present invention provides a method for diagnosing a slow response fault of a rear oxygen sensor. Figure 1 As shown, including:

[0045] S101. Monitor engine operation status parameters and rear oxygen sensor status parameters during engine operation.

[0046] In a specific implementation process, the engine operation state parameter at least includes an engine fuel supply state parameter. Optionally, the engine operation state parameter includes: an engine fuel supply state parameter, an engine current speed, and an engine fault state parameter.

[0047] In a specific implementation process, the working state parameter of the rear oxygen sensor at least includes the working temperature of the rear oxygen sensor. Optionally, the working state parameter of the rear oxygen sensor includes the working temperature and the measured voltage value of the rear oxygen sensor.

[0048] S102: determining whether the engine has entered a first operating condition according to the engine operating state parameters, and determining whether the rear oxygen sensor is in a preset operating state according to the operating state parameters of the rear oxygen sensor.

[0049] If the results of step S102 are all yes, then execute step S103; otherwise, return to step S101.

[0050] Optionally, if the engine operating state parameters include: engine fuel supply state parameters, engine current speed, and engine fault state parameters, the engine is determined to enter the first operating condition according to the engine operating state parameters in the following manner:

[0051] If the current engine speed is greater than a preset speed threshold, and the engine is determined to be in a fuel cut-off state according to the engine fuel 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 operating condition.

[0052] Similarly, if some parameters of the engine operating state parameters are omitted compared to the above implementation, then the corresponding steps can also be omitted in the process of determining whether the engine enters the first operating condition, which will not be repeated here.

[0053] Specifically, the working state parameters of the rear oxygen sensor include the working temperature and the measured voltage value of the rear oxygen sensor. Whether the rear oxygen sensor is in the preset working state is determined 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 and the measured voltage value is greater than a preset voltage threshold, it is determined that the rear oxygen sensor is in a preset working state.

[0055] Similarly, if the working state parameter of the rear oxygen sensor omits the measured voltage value compared with the above embodiment, the corresponding step of determining whether the rear oxygen sensor is in the preset working state can also be omitted, which will not be repeated here.

[0056] S103: Monitor the measured voltage value of the rear oxygen sensor.

[0057] S104: Determine whether the engine is in the second operating condition.

[0058] In a specific implementation process, whether the engine is in the second operating condition is determined by the following method:

[0059] If it is determined according to the engine fuel supply state parameter that the engine is in a fuel cut-off state and the duration of the fuel cut-off state is greater than a target time threshold, it is determined that the engine is in a second operating condition during the duration of the fuel cut-off state.

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

[0061] As another optional implementation, the target time threshold is determined by:

[0062] The target time threshold is determined according to the preset corresponding relationship between the air flow and the target time threshold, based on the air flow at the position of the rear oxygen sensor when the second operating condition starts. The larger the air flow, the larger the corresponding time threshold.

[0063] In this way, it is possible to determine whether to perform subsequent diagnosis of the slow response fault of the rear oxygen sensor according to the fuel cut-off state of the engine, so that adaptive diagnosis can be performed for different second operating conditions, thereby improving the versatility of the solution.

[0064] If the result of step S104 is yes, execute step S105; if the result of step S104 is no, return to step S101.

[0065] S105: Determine whether, during the duration of the second operating condition, the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition.

[0066] Specifically, it is determined in the following manner whether the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition during the duration of the second operating condition:

[0067] If during the duration of the second operating condition, the range of the measured voltage value is greater than the target range threshold corresponding to the second operating condition, and the measured voltage value is within the target voltage range corresponding to the second operating condition (i.e., during the duration of the second operating condition, 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), then it is determined that the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition.

[0068] As an optional implementation, the target extreme difference thresholds corresponding to different second operating conditions are the same preset extreme difference thresholds.

[0069] As another optional implementation, the target range threshold is determined by:

[0070] The preset corresponding relationship between the air flow and the extreme difference threshold is used to determine the target extreme difference threshold according to the air flow at the position of the rear oxygen sensor when the second operating condition starts. The larger the air flow, the larger the corresponding extreme difference threshold.

[0071] As an optional implementation, the target voltage ranges corresponding to different second operating conditions are the same preset voltage range.

[0072] As another optional implementation, the target voltage range is determined by:

[0073] The target voltage range is determined according to the preset correspondence between the air flow rate and the voltage range and the air flow rate at the rear oxygen sensor position when the second operating condition starts. The larger the air flow rate, the larger the upper limit of the corresponding voltage range.

[0074] In this way, the target extreme value / target voltage range is determined by using the air flow at the rear oxygen sensor position, so that adaptive diagnosis can be performed for different second operating conditions, thereby improving the versatility of the solution.

[0075] If the result of step S105 is yes, execute step S106; if the result of step S105 is no, return to step S101.

[0076] S106: Determine that during the duration of the second operating condition, the response range of the rear oxygen sensor is in a normal state.

[0077] S107: Determine whether, during the duration of the second operating condition, the average change rate of the measured voltage value is greater than a target change rate threshold corresponding to the second operating condition.

[0078] In the technical solution of the embodiment of the present invention, the average rate of change of the measured voltage value is △ V is calculated as follows:

[0079]

[0080] Among them, 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 start time of the second working condition. Generally, since the engine will gradually reduce the exhaust volume after the fuel is cut off, the measured voltage value of the rear oxygen sensor will gradually decrease. △ V is usually a negative number.

[0081] Further optionally, the target change rate threshold is determined by:

[0082] The target change rate threshold is determined according to the preset correspondence between the air flow and the change rate threshold, based on the air flow at the position of the rear oxygen sensor when the second operating condition starts. The larger the air flow, the larger 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 adopted, so that adaptive diagnosis can be performed for different second operating conditions, thereby improving the versatility of the solution.

[0084] If the result of step S107 is yes, execute step S108; if the result of step S107 is no, return to step S101.

[0085] S108: Determine that during the duration of the second operating condition, the response speed of the rear oxygen sensor is too slow.

[0086] S109: 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state.

[0087] If the result of step S109 is yes, execute step S110; if the result of step S109 is no, return to step S101.

[0088] As an optional implementation manner, the step S109, judging 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state, specifically includes:

[0089] Determine whether a first number of second operating 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 an overly slow state within a preset time period is greater than a preset alarm number threshold; if the first number is greater than the preset alarm number threshold, it is determined that a slow response fault occurs in the rear oxygen sensor.

[0090] For example, the preset duration is 2 hours. During these 2 hours, the engine enters the second operating condition 12 times in total where the response range of the rear oxygen sensor is normal and the response speed of the rear oxygen sensor is too slow. If the preset alarm quantity threshold is 10, it is determined that the rear oxygen sensor has a slow response fault.

[0091] As another optional implementation, the step S109, judging 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state, specifically includes:

[0092] Determine the second operating condition in which the response range of the rear oxygen sensor belongs to the normal state according to the second number of occurrences in the time sequence from the back to the front, and the third number of the second operating condition in which the response speed of the rear oxygen sensor belongs to the too slow state; judge whether the ratio of the third number to the second number is greater than the preset alarm ratio threshold; if the ratio is greater than the preset alarm ratio threshold, determine that the rear oxygen sensor has a slow response fault. Wherein, the second number is not greater than the preset statistical number threshold.

[0093] For example, the preset statistical quantity threshold is set to 5. The engine enters a total of 12 second operating conditions where the response range of the rear oxygen sensor belongs to the normal state. In the last 5 second operating conditions where the response range of the rear oxygen sensor belongs to the normal state, the response speed of the rear oxygen sensor belongs to the too slow state in 4 of the second operating conditions. If the preset alarm ratio threshold is 60%, it is determined that the rear oxygen sensor has a slow response fault.

[0094] As another optional implementation, the step S109, judging 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state, specifically includes:

[0095] Determine after the engine is started, a fourth number of the second operating condition in which the response range of the rear oxygen sensor is in a normal state, and a fifth number of the second operating condition 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 an overly slow state; determine whether a ratio of the fifth number to the fourth number is greater than a preset alarm ratio threshold; if the ratio is greater than the preset alarm ratio threshold, determine that a slow response fault occurs in the rear oxygen sensor.

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

[0097] S110: Determine that the rear oxygen sensor has a slow response fault and issue an alarm.

[0098] In the specific implementation process, the alarm may be given by lighting a fault lamp, emitting an alarm tone through a speaker, popping up an alarm prompt message on the vehicle computer interface, etc. The embodiment of the present invention is not limited in detail here.

[0099] The method for diagnosing a rear oxygen sensor slow response fault provided by an embodiment of the present invention excludes possible fault types such as no response and random response of the rear oxygen sensor according to the change range of the voltage measurement value of the rear oxygen sensor when the engine is in a fuel cut-off condition that meets the requirements, and determines whether the response speed of the rear oxygen sensor is in a too slow state according to whether the change rate of the voltage measurement value of the rear oxygen sensor is greater than the change amount threshold matching the current working condition after determining that the response range of the rear oxygen sensor belongs to the normal state. Finally, it is finally determined whether the rear oxygen sensor has a slow response fault according to the number of times that the response range of the rear oxygen sensor belongs to the normal state but the response speed belongs to the too slow state, thereby avoiding misjudgment caused by accidental errors. In addition, by determining that the engine is in a condition that meets the diagnostic conditions of the rear oxygen sensor according to the operating state parameters of the engine during the operation of the engine, and determining that the state of the rear oxygen sensor is in a preset working state according to the parameters of the rear oxygen sensor, the slow response diagnosis process of the rear oxygen sensor is triggered, so that the rear oxygen sensor can be diagnosed for slow response without affecting the driving of the vehicle, avoiding the influence of the engine power fluctuation caused by active fuel cut-off on the power and ride of the whole vehicle, and avoiding interference with the normal driving of the vehicle.

[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 As shown, including:

[0101] The diagnostic trigger module M1 is used to monitor the engine operation state parameters and the rear oxygen sensor working state parameters during the engine operation; if it is determined that the engine enters the first working condition according to the engine operation state parameters, and at the same time, it is determined that the rear oxygen sensor is in a preset working state according to the rear oxygen sensor working state parameters, then the measured voltage value of the rear oxygen sensor is monitored;

[0102] A first diagnostic module M2 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 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 is configured to determine that the response speed of the rear oxygen sensor is too slow if, during the duration of the second operating condition, the 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 used to determine whether the rear oxygen sensor has a slow response fault according to the number of second operating 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 an overly slow state.

[0105] Optionally, the engine operating state parameters include current engine speed, engine fuel supply state parameters and engine fault state parameters;

[0106] The step of determining that the engine enters the first operating condition according to the engine operating state parameter comprises:

[0107] If the current engine speed is greater than a preset speed threshold, and the engine is determined to be in a fuel cut-off state according to the engine fuel 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 operating condition.

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

[0109] The determining, according to the rear oxygen sensor working state parameter, that the rear oxygen sensor is in a preset working state includes:

[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, it is determined that the rear oxygen sensor is in a preset working state.

[0111] Optionally, determining that the engine is in the second operating condition is performed in the following manner:

[0112] If it is determined according to the engine fuel supply state parameter that the engine is in a fuel cut-off state and the duration of the fuel cut-off state is greater than a target time threshold, it is determined that the engine is in a second operating condition during the duration of the fuel cut-off state.

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

[0114] Determining the target time threshold according to the air flow at the position of the rear oxygen sensor when the second operating condition starts, using a preset correspondence between the air flow and the time threshold;

[0115] Among them, the larger the air flow rate, the larger the corresponding time threshold.

[0116] Optionally, it is determined whether the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition during the duration of the second operating condition of the engine by:

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

[0118] Optionally, the target range threshold corresponding to the second operating condition is determined by:

[0119] The preset corresponding relationship between the air flow and the extreme difference threshold is used to determine the target extreme difference threshold according to the air flow at the position of the rear oxygen sensor when the second operating condition starts. The larger the air flow, the larger the corresponding extreme difference threshold.

[0120] Optionally, the target voltage range corresponding to the second operating condition is determined in the following manner:

[0121] The target voltage range is determined according to the preset correspondence between the air flow rate and the voltage range and the air flow rate at the position of the rear oxygen sensor when the second operating condition starts, wherein the larger the air flow rate, the larger the upper limit of the corresponding voltage range.

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

[0123] Determining the target change rate threshold value according to the air flow at the position of the rear oxygen sensor when the second operating condition starts, using a preset correspondence relationship between the air flow and the change rate threshold value;

[0124] Among them, the larger the air flow rate, the larger the corresponding change rate threshold.

[0125] Optionally, judging 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state specifically includes:

[0126] Determine after the engine is started, a fourth number of the second operating condition in which the response range of the rear oxygen sensor is in a normal state, and a fifth number of the second operating condition in which the response speed of the rear oxygen sensor is in an overly slow state; determine whether a ratio of the fifth number to the fourth number is greater than a preset alarm ratio threshold; if the ratio is greater than the preset alarm ratio threshold, determine that a slow response fault occurs in the rear oxygen sensor.

[0127] It should be understood that the above-described embodiment of the rear oxygen sensor slow response fault diagnosis device is merely illustrative. For example, the division of the modules is merely a logical function division. 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 the individual unit modules may exist physically, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional unit. 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 by 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 will not be 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 the specific implementation process, the device may have relatively large differences due to different configurations or performances, and may include one or more processors 110, memory 120, and computer-readable storage medium 130. The memory 120 and / or computer-readable storage medium 130 include one or more applications 131 or data 132. The memory 120 and / or 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. Among them, the memory 120 and the computer-readable storage medium 130 may be short-term storage or persistent storage. The application 131 may include one or more modules ( Figure 3 ), each module may include a series of instruction operations. Further, 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, wherein the network interface 140 includes a wired network interface 141 and / or a wireless network interface 142; and one or more input / output interfaces 143.

[0132] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program code runs on a computer, the computer executes the rear oxygen sensor slow response fault diagnosis method.

[0133] The readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a server or a data center that includes one or more available media. The available medium may 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 (DVD), a video compact disc (VCD)), or a semiconductor medium (such as a solid state disk (SSD)).

[0134] Since the principle of solving the problem by the above-mentioned readable storage medium is consistent with the above-mentioned rear oxygen sensor slow response fault diagnosis method, the implementation of the above-mentioned readable storage medium can refer to the implementation of the method, and the repeated parts will not be repeated.

[0135] Based on the same inventive concept, an embodiment of the present invention further provides a computer program product, which includes: computer program code, when the computer program code is run on a computer, the computer executes the rear oxygen sensor slow response fault diagnosis method.

[0136] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a readable storage medium, or transmitted from a readable storage medium to another readable storage medium, for example, the computer instructions may be transmitted from a website site, a computer, a server, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server, or data center.

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

[0138] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0139] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, 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 device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0140] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0141] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0142] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for diagnosing a slow response fault of a rear oxygen sensor, characterized in that: include: Monitor engine operating state parameters and rear oxygen sensor working state parameters during engine operation; If it is determined according to the engine operating state parameter that the engine enters the first operating condition, and it is determined according to the rear oxygen sensor operating state parameter that the rear oxygen sensor is in a preset operating state, monitoring the measured voltage value of the rear oxygen sensor; 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, it is determined that the response range of the rear oxygen sensor belongs to a normal state; If during the duration of the second operating condition, the average change rate of the measured voltage value is greater than the target change rate threshold corresponding to the second operating condition, it is determined that the response speed of the rear oxygen sensor is in a too slow state; Whether a slow response fault occurs in the rear oxygen sensor is determined according to the number of second operating 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 an excessively slow state.

2. The method according to claim 1, characterized in that The engine running state parameters include the current engine speed, the engine fuel supply state parameters and the engine fault state parameters; The step of determining that the engine enters the first operating condition according to the engine operating state parameter comprises: If the current engine speed is greater than a preset speed threshold, and the engine is determined to be in a fuel cut-off state according to the engine fuel 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 a first operating condition; The rear oxygen sensor working state parameters include the temperature and measured voltage value of the rear oxygen sensor; The determining, according to the rear oxygen sensor working state parameter, that the rear oxygen sensor is in a preset working state includes: 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 working state.

3. The method according to claim 1, characterized in that The engine is in the second operating condition as follows: If it is determined according to the engine fuel supply state parameter that the engine is in a fuel cut-off state and the duration of the fuel cut-off state is greater than a target time threshold, it is determined that the engine is in a second operating condition during the duration of the fuel cut-off state.

4. The method according to claim 3, characterized in that The target time threshold is determined by: Determining the target time threshold according to the air flow at the position of the rear oxygen sensor when the second operating condition starts, using a preset correspondence between the air flow and the time threshold; Among them, the larger the air flow rate, the larger the corresponding time threshold.

5. The method according to claim 1, characterized in that Determine whether the value variation range of the measured voltage value meets the value variation range requirement corresponding to the second operating condition during the duration of the second operating condition of the engine by the following method: If, during the duration of the second operating condition, the range of the measured voltage value is greater than the target range threshold corresponding to the second operating condition, and the measured voltage value is within the target voltage range corresponding to the second operating condition, then it is determined that the numerical variation range of the measured voltage value meets the numerical variation range requirement corresponding to the second operating condition.

6. The method according to claim 1, characterized in that The target change rate threshold corresponding to the second operating condition is determined by: Determining the target change rate threshold value according to the air flow at the position of the rear oxygen sensor when the second operating condition starts, using a preset correspondence relationship between the air flow and the change rate threshold value; Among them, the larger the air flow rate, the larger the corresponding change rate threshold.

7. A rear oxygen sensor slow response fault diagnosis device, characterized in that: include: A diagnostic trigger module is used to monitor engine operating state parameters and rear oxygen sensor operating state parameters during engine operation; If it is determined according to the engine operating state parameter that the engine enters the first operating condition, and it is determined according to the rear oxygen sensor operating state parameter that the rear oxygen sensor is in a preset operating state, monitoring the measured voltage value of the rear oxygen sensor; a first diagnostic module, configured to determine that the response range of the rear oxygen sensor is in a normal state 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; a second diagnostic module, configured to determine that a response speed of the rear oxygen sensor is in an overly slow state 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; The third diagnostic module is used 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 in a normal state and the response speed of the rear oxygen sensor is in an excessively slow state.

8. An electronic device, characterized in that: include: a processor and a memory for storing instructions executable by the processor; Wherein, the processor is configured to execute the instructions to implement the rear oxygen sensor slow response fault diagnosis method as described in any one of claims 1-6.

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

10. A computer program product, characterized in that The computer program product comprises: a computer program code, which, when executed on a computer, enables the computer to execute the rear oxygen sensor slow response fault diagnosis method as claimed in any one of claims 1 to 6.

Images