Rear oxygen sensor response delay fault diagnosis method, device and equipment and storage medium
By adjusting the engine's air-fuel ratio to alternate between rich and lean conditions, the response delay time of the rear oxygen sensor is obtained, solving the problem of the inability to diagnose response delay faults in existing technologies. This enables reliable diagnosis of rear oxygen sensor faults and meets regulatory requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-04-07
AI Technical Summary
Existing technologies cannot effectively diagnose response delay faults in post-oxygen sensors and cannot meet increasingly stringent OBD regulations.
The engine air-fuel ratio is automatically adjusted by preset adjustment rules, causing the engine air-fuel ratio to alternate between rich and lean. The response delay time of the oxygen sensor during the process of the air-fuel ratio changing from rich to lean is obtained to determine whether there is a response delay fault.
It enables reliable diagnosis of post-oxygen sensor response delay faults, meets current regulatory requirements, and provides reliable compliance assurance.
Smart Images
Figure CN121808617A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of fault diagnosis technology, and in particular to a method, apparatus, device and storage medium for diagnosing faults caused by the response delay of a post-oxygen sensor. Background Technology
[0002] As is well known, the downstream oxygen sensor, also known as the after-catalytic converter, is installed after the three-way catalytic converter to detect the oxygen concentration in the exhaust gas after catalytic purification. The oxygen concentration measured by the downstream oxygen sensor is of great significance for the Electronic Control Unit (ECU) to monitor the operating status of the three-way catalytic converter, assist in emission control, and optimize the air-fuel ratio. Therefore, the aging diagnosis of the downstream oxygen sensor plays an indispensable role in the entire engine electronic control system.
[0003] With increasingly stringent OBD regulations in major global markets (such as China VII, Euro 7, and California, USA), more precise requirements have been placed on the fault monitoring of the after-oxygen sensor. The new regulations require the ability to detect two main types of faults: slow response faults and delayed response faults. Specifically, a slow response fault refers to a decrease in the signal gradient of the after-oxygen sensor, meaning its signal change rate is lower than the actual change rate of the air-fuel ratio in the exhaust gas; this represents a decrease in signal responsiveness. A delayed response fault refers to a time lag in the after-oxygen sensor's response to changes in the air-fuel ratio; this represents a timing deviation. Both types of faults occur during dynamic changes in the air-fuel ratio (rich → lean or lean → rich), and their occurrence patterns can be further subdivided into: symmetrical type: the fault occurs in both the "rich to lean" and "lean to rich" directions; and asymmetrical type: the fault occurs only in a single direction, either "rich to lean" or "lean to rich."
[0004] In traditional implementations, the slow response of the rear oxygen sensor is usually determined by calculating the voltage slope or time constant of the rear oxygen sensor during engine fuel cut-off conditions or active adjustment of the air-fuel ratio.
[0005] However, due to increasingly stringent OBD regulations, it is necessary to diagnose the response delay fault of the rear oxygen sensor; however, the above methods can only diagnose the slow response fault of the rear oxygen sensor, but cannot detect the response delay fault of the rear oxygen sensor. Summary of the Invention
[0006] Based on this, this application provides a method, apparatus, device, and storage medium for diagnosing the response delay fault of a rear oxygen sensor. By automatically adjusting the engine air-fuel ratio through preset adjustment rules, the engine air-fuel ratio alternates between rich and lean, thereby obtaining the response delay time of the rear oxygen sensor during the process of the air-fuel ratio changing from rich to lean, and determining whether the rear oxygen sensor has a response delay fault. This fills the gap in the existing technology for diagnosing response delay faults and provides reliable compliance assurance to meet the latest regulatory requirements.
[0007] Firstly, a method for diagnosing post-oxygen sensor response delay faults is provided, the method comprising: Obtain the vehicle's enabling condition information and determine whether the diagnostic requirements are met based on the enabling condition information; If so, the engine air-fuel ratio is adjusted according to the preset adjustment rules to obtain the maximum voltage value of the rear oxygen sensor; Obtain the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor. The response delay time value of the rear oxygen sensor is obtained based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, and preset reference value. Based on the response delay time value and the preset delay reference time value, the response delay fault diagnosis result of the post-oxygen sensor is obtained.
[0008] According to one achievable method in an embodiment of this application, the enabling condition information includes multiple items from vehicle speed information, engine speed information, engine load information, ambient temperature information, exhaust flow information, catalytic converter temperature condition information, and rear oxygen sensor heating status information. Determining whether diagnostic requirements are met based on the enabling condition information includes: Based on preset vehicle speed, preset engine speed range, preset engine load, preset ambient temperature, preset exhaust flow integral value and variation range, preset catalyst temperature condition value and variation range, and preset heating status, determine whether multiple items in the corresponding vehicle speed information, engine speed information, engine load information, ambient temperature information, exhaust flow information, catalyst temperature condition information, and rear oxygen sensor heating status information meet the preset requirements. If yes, then the diagnostic requirements are met; if no, then the diagnostic requirements are not met.
[0009] According to one achievable method in an embodiment of this application, the preset adjustment rule includes adjusting the engine air-fuel ratio to a first preset target value and a second preset target value; then, adjusting the engine air-fuel ratio according to the preset adjustment rule to obtain the maximum voltage value of the rear oxygen sensor includes: Adjust the engine air-fuel ratio to the first preset target value and monitor the real-time voltage value of the oxygen sensor. When the real-time voltage value of the rear oxygen sensor is detected to be greater than the first preset voltage value, the engine air-fuel ratio is adjusted to the second preset target value, and the real-time voltage value of the rear oxygen sensor is monitored again. The real-time voltage values of the post-oxygen sensor are sequentially compared according to a preset cycle to obtain the maximum voltage value of the post-oxygen sensor.
[0010] According to one achievable method in an embodiment of this application, the preset reference value includes a preset air-fuel ratio reference value, a preset time reference value, a preset first voltage reference value, and a preset second voltage reference value; based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, and the preset reference value, the response delay time value of the post-oxygen sensor is obtained, including: The cumulative response time value is obtained based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, preset air-fuel ratio reference value, preset time reference value, and preset second voltage reference value. The corrected response time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; The response delay time value is obtained based on the cumulative response time value and the corrected response time value.
[0011] According to one achievable method in an embodiment of this application, the cumulative response time value is obtained based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, the preset air-fuel ratio reference value, the preset time reference value, and the preset second voltage reference value, including: The timing operation is initiated based on the real-time target air-fuel ratio, the preset air-fuel ratio reference value, and the real-time voltage value. The timing response time value is monitored in real time. Based on the timing response time value, the preset time reference value, the real-time voltage value, the maximum voltage value, and the preset second voltage reference value, the timing operation is terminated, and the cumulative response time value is obtained.
[0012] According to one achievable method in an embodiment of this application, a corrected response time value is obtained based on a maximum voltage value, a real-time voltage value, a preset first voltage reference value, and a preset second voltage reference value, including: The transition time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; The corrected response time value is obtained based on the transition time value, the preset first voltage reference value, and the preset second voltage reference value.
[0013] According to one achievable method in an embodiment of this application, the response delay fault diagnosis result includes "no response delay fault" and "response delay fault". Based on the response delay time value and a preset delay reference time value, the response delay fault diagnosis result of the post-oxygen sensor is obtained, including: The response delay time value is compared with the preset delay reference time value. If the response delay time value is less than or equal to the preset delay reference time value, then the post-oxygen sensor does not have a response delay fault. If the response delay time value is greater than the preset delay reference time value, then the post-oxygen sensor has a response delay fault.
[0014] Secondly, a fault diagnosis device for post-oxygen sensor response delay is provided, the device comprising: The first acquisition unit is used to acquire the vehicle's enabling condition information and determine whether the diagnostic requirements are met based on the enabling condition information. The preset adjustment unit is used to adjust the engine air-fuel ratio according to the preset adjustment rules if the condition is met, so as to obtain the maximum voltage value of the rear oxygen sensor. The second acquisition unit is used to acquire the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor. The correction delay unit is used to obtain the response delay time value of the rear oxygen sensor based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value and preset reference value; The diagnostic results unit is used to obtain the response delay fault diagnosis results of the post-oxygen sensor based on the response delay time value and the preset delay reference time value.
[0015] Thirdly, a computer device is provided, comprising: At least one processor; and A memory that is communicatively connected to at least one processor; wherein, The memory stores computer instructions that can be executed by at least one processor to enable the at least one processor to perform the methods involved in the first aspect above.
[0016] Fourthly, a computer-readable storage medium is provided having computer instructions stored thereon for causing a computer to perform the methods described in the first aspect above.
[0017] According to the technical content provided in the embodiments of this application, by acquiring the vehicle's enabling condition information, it is determined whether the diagnostic requirements are met based on the enabling condition information; if so, the engine air-fuel ratio is adjusted according to a preset adjustment rule to obtain the maximum voltage value of the rear oxygen sensor; the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor are acquired; based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, and a preset reference value, the response delay time value of the rear oxygen sensor is obtained; based on the response delay time value and the preset delay reference time value, the response delay fault diagnosis result of the rear oxygen sensor is obtained. The aforementioned operation automatically adjusts the engine air-fuel ratio through preset adjustment rules, causing the engine air-fuel ratio to alternate between rich and lean states, thereby obtaining the response delay time of the rear oxygen sensor during the process of the air-fuel ratio changing from rich to lean, and determining whether the rear oxygen sensor has a response delay fault. This fills the gap in the prior art in response delay fault diagnosis, providing reliable compliance assurance to meet the latest regulatory requirements. Attached Figure Description
[0018] Figure 1 This is a flowchart illustrating a method for diagnosing post-oxygen sensor response delay faults in one embodiment. Figure 2 This is a schematic diagram comparing the normal post-oxygen sensor voltage signal with the rich-to-lean response delay and slow voltage signal when adjusting the engine air-fuel ratio in a method for diagnosing post-oxygen sensor response delay faults in one embodiment. Figure 3 This is a schematic diagram showing the overall change of the voltage signal of the rear oxygen sensor when adjusting the engine air-fuel ratio in a method for diagnosing a fault in the response delay of a rear oxygen sensor in one embodiment. Figure 4 This is a schematic diagram of a preferred flow of a post-oxygen sensor response delay fault diagnosis method in one embodiment; Figure 5 This is a structural block diagram of a post-oxygen sensor response delay fault diagnosis device in one embodiment; Figure 6 This is a schematic structural diagram of a computer device in one embodiment. Detailed Implementation
[0019] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the scope of the present application.
[0020] To facilitate understanding, the system to which this application applies will first be described. This application provides a method for diagnosing a fault in the response delay of a rear oxygen sensor, which can be applied to an Engine Management System (EMS). The EMS is the "brain and central nervous system" of a modern automotive internal combustion engine. It is a complex network composed of sensors, actuators, and an electronic control unit (ECU). Its core objective is to control engine operation with maximum efficiency while meeting emission regulations, fuel economy, and driving performance requirements. Specifically, the ECU, the "brain" of the entire system, receives data from all sensors, performs millions of calculations per second based on internally stored "pulse maps," and then issues precise commands to each actuator. Sensors, including but not limited to the front and rear oxygen sensors, are the "sensors" of the ECU, used to monitor engine operating conditions in real time. Actuators, the "hands and feet" of the ECU, are responsible for executing the commands of the ECU.
[0021] Figure 1 This is a flowchart illustrating a method for diagnosing a post-oxygen sensor response delay fault, provided in an embodiment of this application. This method can be executed by the engine management system. Figure 1 As shown, the method may include the following steps: Step 101: Obtain the vehicle's enabling condition information and determine whether the diagnostic requirements are met based on the enabling condition information.
[0022] Here, the engine management system can obtain the current vehicle's enabling condition information, and then determine whether the diagnostic requirements are met based on the obtained current vehicle enabling condition information, that is, whether the diagnostic operation for the current vehicle's rear oxygen sensor response delay fault can be initiated.
[0023] Step 103: If so, adjust the engine air-fuel ratio according to the preset adjustment rules to obtain the maximum voltage value of the rear oxygen sensor.
[0024] Here, if the diagnostic requirements are met, the engine management system can automatically adjust the engine air-fuel ratio according to preset adjustment rules to obtain the maximum voltage value of the rear oxygen sensor, which can be represented by Um. If the diagnostic requirements are not met, the current operation will end directly.
[0025] Step 105: Obtain the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor.
[0026] Specifically, the engine management system can obtain the real-time target air-fuel ratio at the location of the front oxygen sensor, which can be represented by Ra. Here, because there is a distance between the engine combustion chamber and the sensor, and combustion takes a certain amount of time, the real-time target air-fuel ratio is initially maintained at a fixed value according to a preset adjustment rule, and then gradually increased until it reaches its maximum point. Simultaneously, the engine management system can also obtain the real-time voltage value of the rear oxygen sensor, which can be represented by Rv. Due to the preset adjustment rule settings, the engine air-fuel ratio will change; therefore, the real-time voltage value of the rear oxygen sensor will also change accordingly. It should be noted that the real-time target air-fuel ratio here is the air-fuel ratio after square wave correction.
[0027] Step 107: Based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, and preset reference value, obtain the response delay time value of the rear oxygen sensor.
[0028] Here, after obtaining the real-time target air-fuel ratio, maximum voltage value, and real-time voltage value, the response delay time value of the rear oxygen sensor can be obtained based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, and preset reference value, which can be represented by Tr.
[0029] Step 109: Based on the response delay time value and the preset delay reference time value, obtain the response delay fault diagnosis result of the post-oxygen sensor.
[0030] Here, after obtaining the response delay time value, the response delay time value can be compared with the preset delay reference time value. Based on the comparison result, the response delay fault diagnosis result of the post-oxygen sensor can be obtained.
[0031] As can be seen, this embodiment of the application obtains the vehicle's enabling condition information and determines whether the diagnostic requirements are met based on the enabling condition information. If so, it adjusts the engine air-fuel ratio according to a preset adjustment rule to obtain the maximum voltage value of the rear oxygen sensor; it obtains the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor; based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, and a preset reference value, it obtains the response delay time value of the rear oxygen sensor; based on the response delay time value and the preset delay reference time value, it obtains the response delay fault diagnosis result of the rear oxygen sensor. The aforementioned operation automatically adjusts the engine air-fuel ratio through preset adjustment rules, causing the engine air-fuel ratio to alternate between rich and lean, thereby obtaining the response delay time of the rear oxygen sensor during the process of the air-fuel ratio changing from rich to lean, and determining whether the rear oxygen sensor has a response delay fault. This fills the gap in the prior art in response delay fault diagnosis and provides reliable compliance assurance to meet the latest regulatory requirements.
[0032] The different steps in the above method flow will be described in detail below. First, the step 101, "determining whether the diagnostic requirements are met based on the enable condition information," will be described in detail with reference to the embodiment.
[0033] Based on preset vehicle speed, preset engine speed range, preset engine load, preset ambient temperature, preset exhaust flow integral value and variation range, preset catalytic converter temperature condition and variation range, and preset heating status, determine whether multiple parameters of the corresponding vehicle speed, engine speed, engine load, ambient temperature, exhaust flow, catalytic converter temperature condition, and rear oxygen sensor heating status meet the preset requirements. If yes, the diagnostic requirements are met; otherwise, the diagnostic requirements are not met.
[0034] The enabling condition information includes multiple items from vehicle speed, engine speed, engine load, ambient temperature, exhaust flow, catalytic converter temperature, and rear oxygen sensor heating status.
[0035] Here, the preset vehicle speed can be set to 20 km / h; the preset engine speed range can be set to 1520 rpm to 3520 rpm; the preset engine load can be set to 20%; the preset ambient temperature can be set to -7℃; the preset exhaust flow integral value and variation range can be set to 0.1 kg and -40 kg / h to 40 kg / h; the preset catalytic converter temperature condition value and variation range can be set to 200℃ and -100℃ to 100℃; and the preset heating state can be set to a fault-free heating state. Of course, the aforementioned preset thresholds can be set according to the characteristics of different vehicles, engines, and aftertreatment systems; only general settings are given here.
[0036] Specifically, based on preset vehicle speed, preset engine speed range, preset engine load, preset ambient temperature, preset exhaust flow integral value and variation range, preset catalytic converter temperature condition and variation range, and preset heating status, it is determined whether multiple parameters of the corresponding vehicle speed, engine speed, engine load, ambient temperature, exhaust flow, catalytic converter temperature condition, and rear oxygen sensor heating status meet preset requirements. Specifically, it is determined whether the vehicle speed is greater than 20 km / h, the engine speed is within the range of 1520 rpm to 3520 rpm, the engine load is greater than 20%, the ambient temperature is greater than -7℃, the exhaust flow integral value is greater than 0.1 kg and the exhaust flow variation is within the range of -40 kg / h to 40 kg / h, the catalytic converter temperature condition is greater than 200℃ and the variation is within the range of -100℃ to 100℃, and the rear oxygen sensor heating status is in a fault-free heating state. If all the aforementioned conditions meet the preset requirements, the diagnostic requirements are satisfied; if any of the aforementioned conditions are not met, the diagnostic requirements are not satisfied.
[0037] It's important to note that specifying exhaust flow information is crucial because it's a prerequisite for the reliable operation of the rear oxygen sensor. The purpose of setting the exhaust flow integral value in the exhaust flow information is to ensure that the catalytic converter has passed a sufficient volume of exhaust gas before diagnostic conditions are met, thus making it easier to enrich oxygen. This process helps the rear oxygen sensor voltage rise to the rich end, providing a reliable rich-end voltage signal for diagnostics. Setting the range of variation in the exhaust flow information is necessary because determining the preset range of exhaust flow variation values requires covering steady-state conditions during road tests and the WLTC cycle to ensure diagnostic opportunities. Simultaneously, limiting flow fluctuations prevents drastic changes in the rear oxygen sensor voltage due to excessive fluctuations, thereby ensuring diagnostic reliability. In short, setting the exhaust flow information—limiting the exhaust flow integral value and its variation—aims to ensure that the rear oxygen sensor voltage reliably rises to the rich end and maintains signal stability. It should be noted that "road test" refers to actual driving tests on real roads; WLTC is a globally standardized light vehicle test cycle conducted on a chassis dynamometer in a laboratory to certify vehicle fuel consumption and emissions data.
[0038] Before conducting a diagnosis, the above procedures determine whether the basic diagnostic requirements are met. Only if the basic diagnostic requirements are met will the diagnostic procedure be performed, thereby improving the accuracy of subsequent diagnoses.
[0039] The following describes in detail step 103, namely, "adjusting the engine air-fuel ratio according to the preset adjustment rules to obtain the maximum voltage value of the rear oxygen sensor," with reference to the embodiments.
[0040] The engine air-fuel ratio is adjusted to the first preset target value, and the real-time voltage value of the rear oxygen sensor is monitored. When the real-time voltage value of the rear oxygen sensor is found to be greater than the first preset voltage value, the engine air-fuel ratio is adjusted to the second preset target value, and the real-time voltage value of the rear oxygen sensor is monitored again. The real-time voltage values of the rear oxygen sensor are sequentially compared according to a preset cycle to obtain the maximum voltage value of the rear oxygen sensor.
[0041] The preset adjustment rules include adjusting the engine air-fuel ratio to a first preset target value and a second preset target value. The first preset target value can generally be set to 0.90; the second preset target value can generally be set to 1.08; the first preset voltage value can generally be set to 0.9V; and the preset cycle can generally be set to 10ms. Of course, the aforementioned values can be adjusted according to the characteristics of different vehicles, different engines, and different after-treatment systems.
[0042] Specifically, the engine management system automatically adjusts the engine air-fuel ratio from rich to lean, that is, automatically adjusts the engine air-fuel ratio to the first preset target value of 0.90, and monitors the real-time voltage value of the rear oxygen sensor; when the real-time voltage value of the rear oxygen sensor is detected to be greater than the first preset voltage value, that is, Rv>0.9V, the engine air-fuel ratio is adjusted to the second preset target value of 1.08, and the real-time voltage value of the rear oxygen sensor continues to be monitored; at the same time, the real-time voltage value of the rear oxygen sensor is sequentially compared according to a calculation cycle of 10ms, that is, with 10ms as a cycle, if the voltage value of the previous cycle is greater than the current voltage value, the maximum voltage value is updated; if the voltage value of the previous cycle is less than the current voltage value, the current maximum voltage value is maintained, thereby obtaining the maximum voltage value of the rear oxygen sensor.
[0043] It is also important to emphasize here that the adjustment of the engine air-fuel ratio is a cyclical process. After the engine management system adjusts the engine air-fuel ratio to the second preset target value of 1.08, it continues to monitor the real-time voltage value of the rear oxygen sensor. When the real-time voltage value of the rear oxygen sensor is found to be less than the second preset voltage value of Rv<0.2V, the engine air-fuel ratio is then adjusted to the first preset target value of 0.9, and so on.
[0044] It should be noted that after the engine management system automatically adjusts the air-fuel ratio from rich to lean, a comparison diagram of the voltage signal of the oxygen sensor after normal operation and the voltage signal of the response delay from rich to lean can be found in the diagram. Figure 2 As shown in (a), the schematic diagram comparing the voltage signal of the normal voltage sensor with the slow voltage signal of the concentrated-to-dilute response can be referred to. Figure 2 (b) shows the complete change in the voltage signal of the rear oxygen sensor after the engine management system automatically adjusts the air-fuel ratio from rich to lean. Figure 3 As shown.
[0045] During the vehicle's steady-state operation, the engine management system alternately enriches and leans the engine's air-fuel ratio according to preset adjustment rules. As the engine's air-fuel ratio is leaned, the voltage of the rear oxygen sensor decreases from high to low, thus obtaining the maximum voltage value of the rear oxygen sensor. This provides further assurance for subsequent response delay fault diagnosis.
[0046] Next, the above step 107, namely "obtaining the response delay time value of the rear oxygen sensor based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value and preset reference value", will be described in detail with reference to the embodiments.
[0047] The cumulative response time value is obtained based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, preset air-fuel ratio reference value, preset time reference value, and preset second voltage reference value; the corrected response time value is obtained based on the maximum voltage value, real-time voltage value, preset first voltage reference value, and preset second voltage reference value; and the response delay time value is obtained based on the cumulative response time value and the corrected response time value.
[0048] The preset reference values include a preset air-fuel ratio reference value, a preset time reference value, a preset first voltage reference value, and a preset second voltage reference value. The preset air-fuel ratio reference value can generally be set to 1.02; the preset time reference value can generally be set to 2.8 seconds; the preset first voltage reference value can generally be set to 0.01V; and the preset second voltage reference value can generally be set to 0.0354V. Currently, the aforementioned values can be adjusted according to the characteristics of different vehicles, engines, and after-treatment systems.
[0049] In one feasible approach, a timing operation is initiated based on the real-time target air-fuel ratio, a preset air-fuel ratio reference value, and a real-time voltage value; the timing response time value is monitored in real time; and the timing operation is terminated based on the timing response time value, a preset time reference value, a real-time voltage value, a maximum voltage value, and a preset second voltage reference value, thereby obtaining the cumulative response time value.
[0050] Specifically, the timing operation is initiated based on the real-time target air-fuel ratio, the preset air-fuel ratio reference value, and the real-time voltage value. That is, the real-time target air-fuel ratio of the front oxygen sensor is monitored in real time. When the real-time target air-fuel ratio is greater than the preset air-fuel ratio reference value (Ra>1.02), the timing operation is initiated, i.e., timing begins. At this time, the timing response time value is 0. Since the timing response time value changes in real time, it can be monitored in real time after the timing operation is initiated, denoted as Tt. When the timing response time value is greater than the preset time reference value (Tt>2.08), or when the real-time voltage value is less than the difference between the maximum voltage value and the preset second voltage reference value (Rv<(Um-0.0354V), the timing operation ends, and the cumulative response time value, denoted as Tc, is obtained.
[0051] In another possible implementation, the transition time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; the corrected response time value is obtained based on the transition time value, the preset first voltage reference value, and the preset second voltage reference value.
[0052] Specifically, after the voltage of the post-oxygen sensor reaches its maximum value, it begins to decrease. The transition time of the real-time voltage value of the post-oxygen sensor from the maximum voltage value minus a preset first voltage reference value to the maximum voltage value minus a preset second voltage reference value, i.e., the transition time value of Rv from (Um-0.01) to (Um-0.0354), can be represented by Tl. After obtaining the transition time value, the corrected response time value can be obtained based on the transition time value, the preset first voltage reference value, and the preset second voltage reference value, which can be represented by Tm. The specific expression is as follows: Tm = Tl × preset second voltage reference value ÷ (preset second voltage reference value - preset first voltage reference value) =Tl×0.0354÷(0.0354-0.01); After obtaining the cumulative response time value and the corrected response time value, the response delay time value can be obtained based on the difference between the cumulative response time value and the corrected response time value. The specific expression can be represented as follows: Tr = Tc - Tm; It should be noted that the purpose of setting the preset air-fuel ratio reference value and the preset second voltage reference value is mainly to prevent the voltage of the rear oxygen sensor from remaining constant for an extended period, thus preventing the diagnostic process from exiting. Furthermore, if the preset second voltage reference value is set too low, extremely short time intervals can be detected, which is particularly noticeable when the rear oxygen sensor malfunctions. To avoid false readings due to signal noise, the preset second voltage reference value needs to be set sufficiently high, meaning that a large change in the rear oxygen sensor voltage is used to detect signal increases or decreases. Moreover, when calculating the actual delay time of the rear oxygen sensor transitioning from rich to lean, further correction is needed by adjusting the response time value to ensure the accuracy of the final diagnostic result.
[0053] The above operation, by accumulating and correcting the response time value, obtains the response delay time value of the post-oxygen sensor voltage from rich to lean, realizing the function of detecting the delayed response fault of the post-oxygen sensor, and judging whether the post-oxygen sensor has aging problems from another perspective, filling the gap in the field of delayed response fault diagnosis in the existing technology.
[0054] Finally, the above step 109, namely "obtaining the response delay time value of the post-oxygen sensor based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, and preset reference value", will be described in detail with reference to the embodiments.
[0055] The response delay time value is compared with the preset delay reference time value. If the response delay time value is less than or equal to the preset delay reference time value, the rear oxygen sensor does not have a response delay fault; if the response delay time value is greater than the preset delay reference time value, the rear oxygen sensor has a response delay fault.
[0056] The response delay fault diagnosis results include "no response delay fault" and "response delay fault". The preset delay reference time value can be represented by Tb, and can generally be set to 0.85s.
[0057] Specifically, the response delay time value is compared with the preset delay reference time value. When the response delay time value is less than or equal to the preset delay reference time value, i.e., Tr<=Tb, the post-oxygen sensor does not have a response delay fault; when the response delay time value is greater than the preset delay reference time value, i.e., Tr>Tb, the post-oxygen sensor has a response delay fault.
[0058] It should be noted that regardless of whether the response delay fault diagnosis result indicates the presence or absence of a response delay fault, the engine air-fuel ratio needs to be readjusted.
[0059] The above operation, after obtaining the response delay time value, compares the response delay time value with the preset delay reference time value, and then obtains the response delay fault diagnosis result, so as to fill the gap in the field of response delay fault diagnosis of post-oxygen sensors in the prior art.
[0060] Based on the implementation methods in the above embodiments, the following will be combined with... Figure 4 A preferred method flow provided in an embodiment of this application will be described by way of example. For instance... Figure 4 As shown, the method may include the following steps: Step S201: Obtain vehicle enabling condition information, which includes multiple items from vehicle speed information, engine speed information, engine load information, ambient temperature information, exhaust flow information, catalytic converter temperature condition information, and rear oxygen sensor heating status information.
[0061] Step S202: Determine whether the diagnostic requirements are met based on the enable condition information. If yes, proceed to step S203; otherwise, end the diagnosis.
[0062] Step S203: Adjust the engine air-fuel ratio to the first preset target value and monitor the real-time voltage value of the oxygen sensor.
[0063] Step S204: When the real-time voltage value of the rear oxygen sensor is detected to be greater than the first preset voltage value, the engine air-fuel ratio is adjusted to the second preset target value, and the real-time voltage value of the rear oxygen sensor is monitored again.
[0064] Step S205: The real-time voltage values of the post-oxygen sensor are sequentially compared according to a preset cycle to obtain the maximum voltage value of the post-oxygen sensor.
[0065] Step S206: Obtain the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor.
[0066] Step S207: Start the timing operation based on the real-time target air-fuel ratio, the preset air-fuel ratio reference value, and the real-time voltage value.
[0067] Step S208: Monitor the timing response time value in real time. Based on the timing response time value, the preset time reference value, the real-time voltage value, the maximum voltage value, and the preset second voltage reference value, end the timing operation and obtain the cumulative response time value.
[0068] Step S209: Obtain the transition time value based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value.
[0069] Step S210: Obtain the corrected response time value based on the transition time value, the preset first voltage reference value, and the preset second voltage reference value.
[0070] Step S211: Obtain the response delay time value based on the cumulative response time value and the corrected response time value.
[0071] Step S212: Compare the response delay time value with the preset delay reference time value. If the response delay time value is less than or equal to the preset delay reference time value, proceed to step S213; if the response delay time value is greater than the preset delay reference time value, proceed to step S214.
[0072] In step S213, the oxygen sensor does not have a response delay fault.
[0073] In step S214, the oxygen sensor has a response delay fault.
[0074] It should be understood that, although Figure 1 , Figure 4 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated in this application, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Furthermore, Figure 1 , Figure 4At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0075] Figure 5 This is a schematic diagram of a post-oxygen sensor response delay fault diagnosis device provided in an embodiment of this application. This device can be installed in the engine management system to perform functions such as... Figure 1 , Figure 4 The method flow is shown below. Figure 5 As shown, the device may include: a first acquisition unit 301, a preset adjustment unit 303, a second acquisition unit 305, a delay correction unit 307, and a diagnostic result unit 309. The main functions of each component module are as follows: The first acquisition unit 301 is used to acquire the vehicle's enabling condition information and determine whether the diagnostic requirements are met based on the enabling condition information. The preset adjustment unit 303 is used to adjust the engine air-fuel ratio according to the preset adjustment rules if the condition is met, so as to obtain the maximum voltage value of the rear oxygen sensor. The second acquisition unit 305 is used to acquire the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor. The delay correction unit 307 is used to obtain the response delay time value of the rear oxygen sensor based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value and preset reference value. The diagnostic result unit 309 is used to obtain the response delay fault diagnosis result of the post-oxygen sensor based on the response delay time value and the preset delay reference time value.
[0076] In one embodiment, the enabling condition information includes multiple items from vehicle speed information, engine speed information, engine load information, ambient temperature information, exhaust flow information, catalyst temperature condition information, and rear oxygen sensor heating status information; the first acquisition unit 301 is further configured to: Based on preset vehicle speed, preset engine speed range, preset engine load, preset ambient temperature, preset exhaust flow integral value and variation range, preset catalyst temperature condition value and variation range, and preset heating status, determine whether multiple items in the corresponding vehicle speed information, engine speed information, engine load information, ambient temperature information, exhaust flow information, catalyst temperature condition information, and rear oxygen sensor heating status information meet the preset requirements. If yes, then the diagnostic requirements are met; if no, then the diagnostic requirements are not met.
[0077] In one embodiment, the preset adjustment rule includes adjusting the engine air-fuel ratio to a first preset target value and a second preset target value; the preset adjustment unit 303 is further configured to: Adjust the engine air-fuel ratio to the first preset target value and monitor the real-time voltage value of the oxygen sensor. When the real-time voltage value of the rear oxygen sensor is detected to be greater than the first preset voltage value, the engine air-fuel ratio is adjusted to the second preset target value, and the real-time voltage value of the rear oxygen sensor is monitored again. The real-time voltage values of the post-oxygen sensor are sequentially compared according to a preset cycle to obtain the maximum voltage value of the post-oxygen sensor.
[0078] In one embodiment, the preset reference values include a preset air-fuel ratio reference value, a preset time reference value, a preset first voltage reference value, and a preset second voltage reference value; the correction delay unit 307 is further configured to: The cumulative response time value is obtained based on the real-time target air-fuel ratio, maximum voltage value, real-time voltage value, preset air-fuel ratio reference value, preset time reference value, and preset second voltage reference value. The corrected response time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; The response delay time value is obtained based on the cumulative response time value and the corrected response time value.
[0079] In one embodiment, the delay correction unit 307 is further configured to: The timing operation is initiated based on the real-time target air-fuel ratio, the preset air-fuel ratio reference value, and the real-time voltage value. The timing response time value is monitored in real time. Based on the timing response time value, the preset time reference value, the real-time voltage value, the maximum voltage value, and the preset second voltage reference value, the timing operation is terminated, and the cumulative response time value is obtained.
[0080] In one embodiment, the delay correction unit 307 is further configured to: The transition time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; The corrected response time value is obtained based on the transition time value, the preset first voltage reference value, and the preset second voltage reference value.
[0081] In one embodiment, the response delay fault diagnosis result includes "no response delay fault" and "response delay fault"; the diagnosis result unit 309 is further used for: The response delay time value is compared with the preset delay reference time value. If the response delay time value is less than or equal to the preset delay reference time value, then the post-oxygen sensor does not have a response delay fault. If the response delay time value is greater than the preset delay reference time value, then the post-oxygen sensor has a response delay fault.
[0082] The same or similar parts among the above embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments.
[0083] It should be noted that the embodiments of this application may involve the use of user data. In practical applications, user-specific personal data may be used in the scheme described herein within the scope permitted by applicable laws and regulations, provided that it complies with the applicable laws and regulations of the country (e.g., explicit consent from the user, actual notification to the user, explicit authorization from the user, etc.).
[0084] According to embodiments of this application, this application also provides a computer device and a computer-readable storage medium.
[0085] like Figure 6 The diagram shown is a block diagram of a computer device according to an embodiment of this application. The term "computer device" is intended to represent various forms of digital computers or mobile devices. The digital computer may include a desktop computer, a portable computer, a workbench, a personal digital assistant, a server, a mainframe computer, and other suitable computers. The mobile device may include a tablet computer, a smartphone, a wearable device, etc.
[0086] like Figure 6 As shown, the computer device 400 includes a computing unit 401, a ROM 402, a RAM 403, a bus 404, and an input / output (I / O) interface 405. The computing unit 401, ROM 402, and RAM 403 are interconnected via the bus 404. The input / output (I / O) interface 405 is also connected to the bus 404.
[0087] The computing unit 401 can execute various processes in the method embodiments of this application according to computer instructions stored in the read-only memory (ROM) 402 or computer instructions loaded from the storage unit 408 into the random access memory (RAM) 403. The computing unit 401 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. The computing unit 401 can include, but is not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. In some embodiments, the methods provided in the embodiments of this application can be implemented as computer software programs, which are tangibly contained in a computer-readable storage medium, such as the storage unit 408.
[0088] RAM 403 can also store various programs and data required for the operation of computer device 400. Part or all of the computer program can be loaded and / or installed on computer device 400 via ROM 402 and / or communication unit 409.
[0089] The input unit 406, output unit 407, storage unit 408, and communication unit 409 in the computer device 400 can be connected to the I / O interface 405. The input unit 406 can be, for example, a keyboard, mouse, touchscreen, or microphone; the output unit 407 can be, for example, a monitor, speaker, or indicator light. The computer device 400 can exchange information and data with other devices through the communication unit 409.
[0090] It should be noted that the device may also include other components necessary for normal operation. It may also include only the components necessary for implementing the solution of this application, without necessarily including all the components shown in the figures.
[0091] Various implementations of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SOCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof.
[0092] The computer instructions used to implement the methods of this application may be written in any combination of one or more programming languages. These computer instructions may be provided to the computing unit 401 such that when executed by the computing unit 401, such as a processor, the computer instructions cause the execution of the steps involved in the embodiments of the methods of this application.
[0093] The computer-readable storage medium provided in this application can be a tangible medium that can contain or store computer instructions for performing the steps involved in the method embodiments of this application. The computer-readable storage medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, and other forms of storage media.
[0094] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for diagnosing post-oxygen sensor response delay faults, characterized in that, The method includes: Obtain the vehicle's enabling condition information, and determine whether the diagnostic requirements are met based on the enabling condition information; If so, the engine air-fuel ratio is adjusted according to the preset adjustment rules to obtain the maximum voltage value of the rear oxygen sensor; Obtain the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor. The response delay time value of the rear oxygen sensor is obtained based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, and the preset reference value. Based on the response delay time value and the preset delay reference time value, the response delay fault diagnosis result of the post-oxygen sensor is obtained.
2. The method according to claim 1, characterized in that, The enabling condition information includes multiple items from vehicle speed, engine speed, engine load, ambient temperature, exhaust flow rate, catalytic converter temperature, and rear oxygen sensor heating status. Determining whether the diagnostic requirements are met based on the enabling condition information includes: Based on preset vehicle speed, preset engine speed range, preset engine load, preset ambient temperature, preset exhaust flow integral value and variation range, preset catalyst temperature condition value and variation range, and preset heating status, determine whether multiple items in the corresponding vehicle speed information, engine speed information, engine load information, ambient temperature information, exhaust flow information, catalyst temperature condition information, and rear oxygen sensor heating status information meet the preset requirements. If yes, then the diagnostic requirements are met; if no, then the diagnostic requirements are not met.
3. The method according to claim 1, characterized in that, The preset adjustment rule includes adjusting the engine air-fuel ratio to a first preset target value and a second preset target value; The process involves adjusting the engine air-fuel ratio according to a preset adjustment rule to obtain the maximum voltage value of the rear oxygen sensor, including: The engine air-fuel ratio is adjusted to the first preset target value, and the real-time voltage value of the oxygen sensor is monitored. When the real-time voltage value of the rear oxygen sensor is detected to be greater than the first preset voltage value, the engine air-fuel ratio is adjusted to the second preset target value, and the real-time voltage value of the rear oxygen sensor is monitored again. The real-time voltage values of the post-oxygen sensor are sequentially compared according to a preset cycle to obtain the maximum voltage value of the post-oxygen sensor.
4. The method according to claim 3, characterized in that, The preset reference values include a preset air-fuel ratio reference value, a preset time reference value, a preset first voltage reference value, and a preset second voltage reference value; The step of obtaining the response delay time value of the post-oxygen sensor based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, and a preset reference value includes: The cumulative response time value is obtained based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, the preset air-fuel ratio reference value, the preset time reference value, and the preset second voltage reference value; The corrected response time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; The response delay time value is obtained based on the cumulative response time value and the corrected response time value.
5. The method according to claim 4, characterized in that, The step of obtaining the cumulative response time value based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, the preset air-fuel ratio reference value, the preset time reference value, and the preset second voltage reference value includes: The timing operation is initiated based on the real-time target air-fuel ratio, the preset air-fuel ratio reference value, and the real-time voltage value. The timing response time value is monitored in real time. Based on the timing response time value, the preset time reference value, the real-time voltage value, the maximum voltage value, and the preset second voltage reference value, the timing operation is terminated, and the cumulative response time value is obtained.
6. The method according to claim 4, characterized in that, The step of obtaining the corrected response time value based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value includes: The transition time value is obtained based on the maximum voltage value, the real-time voltage value, the preset first voltage reference value, and the preset second voltage reference value; The corrected response time value is obtained based on the transition time value, the preset first voltage reference value, and the preset second voltage reference value.
7. The method according to claim 1, characterized in that, The response delay fault diagnosis result includes "no response delay fault" and "response delay fault". The step of obtaining the response delay fault diagnosis result of the post-oxygen sensor based on the response delay time value and a preset delay reference time value includes: The response delay time value is compared with the preset delay reference time value. If the response delay time value is less than or equal to the preset delay reference time value, then the post-oxygen sensor does not have a response delay fault. If the response delay time value is greater than the preset delay reference time value, then the post-oxygen sensor has a response delay fault.
8. A device for diagnosing post-oxygen sensor response delay faults, characterized in that, The device includes: The first acquisition unit is used to acquire the vehicle's enabling condition information and determine whether the diagnostic requirements are met based on the enabling condition information. The preset adjustment unit is used to adjust the engine air-fuel ratio according to the preset adjustment rules if the condition is met, so as to obtain the maximum voltage value of the rear oxygen sensor. The second acquisition unit is used to acquire the real-time target air-fuel ratio at the location of the front oxygen sensor and the real-time voltage value of the rear oxygen sensor. The delay correction unit is used to obtain the response delay time value of the rear oxygen sensor based on the real-time target air-fuel ratio, the maximum voltage value, the real-time voltage value, and the preset reference value. The diagnostic result unit is used to obtain the response delay fault diagnosis result of the post-oxygen sensor based on the response delay time value and the preset delay reference time value.
9. A computer device, comprising: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores computer instructions executable by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the method of any one of claims 1-7.
10. A computer-readable storage medium storing computer instructions thereon, characterized in that, The computer instructions are used to cause the computer to perform the method according to any one of claims 1 to 7.