Method and system for diagnosing aging of oxygen sensor of hybrid electric vehicle

Abstract

The invention provides an aging diagnosis method and system for an oxygen sensor of a hybrid electric vehicle, and the aging diagnosis method comprises the steps: selecting a diagnosis working condition based on the altitude and in combination with a scavenging rate test result under a corresponding condition; judging whether the running condition of the current vehicle meets a preset condition for aging diagnosis or not; if yes, entering an aging diagnosis mode until aging diagnosis is completed; and if not, normal operation is kept, judgment is repeated till the operation condition of the current vehicle meets the preset condition, and at least one time of aging diagnosis is completed in the process from single-time starting to flameout. According to the configuration, by adding division of the altitude, adding stricter preset conditions in a high-altitude area and repeatedly judging, at least one time of oxygen sensor aging judgment is completed, the situation that aging diagnosis cannot be conducted on a vehicle in the high-altitude area due to the fact that the scavenging rate is too large is avoided, the IUPR molecular value can be effectively improved, and the service life of the vehicle is prolonged. And the IUPR value meets the requirements of laws and regulations.

Description

Technical Field

[0001] The invention relates to the field of hybrid electric vehicles, and in particular to an oxygen sensor aging diagnosis method and system for a hybrid electric vehicle. Background Art

[0002] As regulations on emissions and fuel consumption become increasingly stringent, engine downsizing and high performance have become the main directions of current engine research and development. Small-displacement turbocharged engines are the mainstream choice of current vehicle manufacturers.

[0003] Since the turbine is driven by exhaust gas and has a certain hysteresis, the power output response of a turbocharged engine is often slow at the beginning of rapid acceleration. Because the intake volume is larger than that of a naturally aspirated engine of the same displacement, the temperature and pressure in the cylinder of a turbocharged engine are relatively high, and the tendency to knock is more obvious.

[0004] The above problems can be solved by scavenging. Under medium and low speed and high load conditions, during the intake process of the engine, when the dynamic pressure in the intake manifold exceeds the dynamic pressure in the exhaust manifold, if there is a certain valve overlap angle, the fresh gas in the intake manifold will flow through the cylinder and directly enter the exhaust manifold, taking away some residual exhaust gas in the cylinder. This process is the scavenging of the engine. Scavenging can reduce the residual exhaust gas in the cylinder and increase the fresh gas charge; at the same time, the fresh gas with a lower temperature can have a certain cooling effect, thereby reducing the tendency of knocking and increasing the ignition angle.

[0005] During the scavenging process, the oxygen content of the gas in the exhaust pipe also has strong dynamic characteristics. The signal measured by the oxygen sensor fluctuates strongly, which has an adverse effect on the stability of the closed-loop control. Therefore, the aging diagnosis of the oxygen sensor requires that the scavenging rate should not be too large, generally not exceeding 2%.

[0006] In plateau areas, the air density is lower than that in plains. For the same power demand, the valve overlap angle is larger in plateaus than in plains, so the scavenging is more frequent and the scavenging rate is also greater. Taking a plug-in hybrid vehicle as an example, in plateau tests, the scavenging rate of the engine under common working conditions is almost always above 2%, making it difficult to complete the aging diagnosis of the front oxygen sensor. Even if it is completed occasionally, the IUPR (In Use Performance Rario, actual diagnosis frequency) numerator is difficult to reach the growth condition. The minimum IUPR value of the oxygen sensor in the regulations is required to be 0.336, so it is difficult to meet the regulatory requirements in plateau areas.

[0007] Based on this, how to stably perform aging diagnosis of the front oxygen sensor in plateau areas and make the minimum IUPR value of the oxygen sensor meet regulatory requirements has become a technical problem that technicians in this field need to solve. Summary of the invention

[0008] The purpose of the present invention is to provide a hybrid electric vehicle oxygen sensor aging diagnosis method and system, so as to solve the problem that it is difficult to complete the front oxygen sensor aging diagnosis in plateau areas during actual use, resulting in the IUPR value failing to reach the statutory minimum value.

[0009] In order to achieve the above object, the present invention provides a method for diagnosing aging of an oxygen sensor of a hybrid vehicle, comprising:

[0010] Based on the altitude, combined with the results of the scavenging rate test under the corresponding conditions, select the diagnostic operating condition;

[0011] Determine whether the current operating conditions of the vehicle meet the preset conditions for aging diagnosis;

[0012] If satisfied, then enter the aging diagnosis mode until the aging diagnosis is completed;

[0013] If not, maintain normal operation and repeat the judgment until the current vehicle operating conditions meet the preset conditions and complete the aging diagnosis at least once in a single startup to shutdown process.

[0014] Optionally, the aging diagnosis mode includes:

[0015] The vehicle is running in the diagnostic condition, and the operating parameters of the engine of the vehicle can enter the diagnostic interval multiple times;

[0016] The duration for which the vehicle maintains operation in the diagnostic condition satisfies a preset duration, and the number of times the operating parameters of the engine enter the diagnostic interval satisfies a preset number of times.

[0017] Optionally, the scavenging rate of the diagnostic operating condition is less than a scavenging rate threshold.

[0018] Optionally, the determining whether the current operating condition of the vehicle meets the preset condition for aging diagnosis includes:

[0019] Determining whether the current physical condition of the vehicle meets the first preset condition;

[0020] Determine whether the current vehicle has conditions that inhibit diagnosis.

[0021] Optionally, when the altitude is less than or equal to the calibrated altitude, if the physical condition of the current vehicle meets the first preset condition and there is no condition that inhibits diagnosis for the current vehicle, the aging diagnosis mode is entered until the aging diagnosis is completed.

[0022] Optionally, the physical conditions include: water temperature of the water tank, voltage of the power supply, whether there is a priority operating condition, whether the signal of the oxygen sensor is reasonable, and whether the closed-loop control is within a target range;

[0023] When the water temperature of the water tank and the voltage of the power supply are within the corresponding preset ranges, there is no priority operating condition, the signal of the oxygen sensor is reasonable, and the closed-loop control is within the target range, it is determined that the current physical condition of the vehicle meets the first preset condition.

[0024] Optionally, the determining whether the current operating condition of the vehicle meets the preset condition for aging diagnosis further includes:

[0025] Determining whether the current power demand of the vehicle meets a second preset condition;

[0026] Determine whether the aging diagnosis of the oxygen sensor of the current vehicle has been completed once.

[0027] Optionally, when the altitude is greater than the calibrated altitude, if the physical condition of the current vehicle meets the first preset condition, the current vehicle does not have the condition to suppress diagnosis, the power demand of the current vehicle meets the second preset condition, and the current vehicle has not completed an aging diagnosis of the oxygen sensor, then the aging diagnosis mode is entered until the aging diagnosis is completed.

[0028] Optionally, the power demand includes: target torque change rate, vehicle speed change rate;

[0029] When the target torque change rate and the vehicle speed change rate are both less than or equal to corresponding thresholds, it is determined that the current power demand of the vehicle meets the second preset condition.

[0030] In order to achieve the above object, the present invention also provides an oxygen sensor aging diagnosis system for a hybrid vehicle, comprising: a test module, a judgment module, a control module and a measurement module;

[0031] The test module is used to select a diagnostic condition based on the altitude and the result of the scavenging rate test under the corresponding situation, and send the diagnostic condition to the control module;

[0032] The judgment module is respectively connected to the control module and the measurement module for communication;

[0033] The judgment module is used to receive the current operating conditions of the vehicle obtained by the measurement module, and judge whether the preset conditions for aging diagnosis are met; and send the judgment result to the control module;

[0034] The control module controls the current vehicle to enter an aging diagnosis mode or maintain normal operation based on the judgment result.

[0035] Optionally, the current operating conditions of the vehicle include: physical conditions, whether there are conditions that inhibit diagnosis, power requirements, and whether aging diagnosis of the oxygen sensor has been completed once.

[0036] Optionally, the judgment module is configured to, when the altitude is less than or equal to the calibrated altitude, if the physical condition of the current vehicle meets the preset condition and there is no condition for suppressing diagnosis in the current vehicle, judge that the operating condition of the current vehicle meets the preset condition for performing aging diagnosis;

[0037] The control module is configured to control the current vehicle to enter the aging diagnosis module when the operating condition of the current vehicle meets the preset condition for aging judgment.

[0038] Optionally, the judgment module is configured to, when the altitude is greater than the calibrated altitude, if the physical condition of the current vehicle meets the preset condition, the current vehicle does not have the condition to inhibit diagnosis, the power demand of the current vehicle meets the preset condition, and the current vehicle has not completed an aging diagnosis of the oxygen sensor, then judge that the operating condition of the current vehicle meets the preset condition for aging diagnosis;

[0039] The control module is configured to control the current vehicle to enter the aging diagnosis module when the operating condition of the current vehicle meets the preset condition for aging judgment.

[0040] Optionally, the aging diagnosis mode includes:

[0041] The vehicle is running in the diagnostic condition, and the operating parameters of the engine of the vehicle can enter the diagnostic interval multiple times;

[0042] The duration for which the vehicle maintains operation in the diagnostic condition satisfies a preset duration, and the number of times the operating parameters of the engine enter the diagnostic interval satisfies a preset number of times.

[0043] Compared with the existing oxygen sensor aging diagnosis method, the hybrid vehicle oxygen sensor aging diagnosis method provided by the present application has the following advantages:

[0044] By increasing the division of altitude, adding stricter preset conditions in high-altitude areas, and repeatedly judging, at least one oxygen sensor aging judgment is completed, so as to avoid the situation where the vehicle cannot perform aging diagnosis due to excessive scavenging rate in high-altitude areas. It can also effectively improve the IUPR molecular value so that the IUPR value meets regulatory requirements. At the same time, looser preset conditions are adopted in low-altitude areas, so that the vehicle can ensure at least one oxygen sensor aging judgment in the whole altitude range from a single start to shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart of a first hybrid vehicle oxygen sensor aging diagnosis method provided by an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structure of an oxygen sensor aging diagnosis system for a hybrid vehicle provided by an embodiment of the present invention;

[0047] Figure 3 A flow chart of a second hybrid vehicle oxygen sensor aging diagnosis method provided by an embodiment of the present invention;

[0048] Figure 4 A flowchart of a third hybrid vehicle oxygen sensor aging diagnosis method provided by an embodiment of the present invention;

[0049] The description of each reference numeral is as follows:

[0050] 100 - test module; 200 - judgment module; 300 - control module; 400 - measurement module. DETAILED DESCRIPTION

[0051] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0052] As used in this specification, the singular forms "a", "an" and "the" include plural objects, the term "or" is generally used to include the meaning of "and / or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "the proximal end" and "the distal end" generally refer to two corresponding parts, which include not only the endpoints, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in this specification, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and it cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element may be in any orientation such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. The terms "upper", "lower", "top" and "bottom" are generally relative position relationships arranged in the direction of gravity; the terms "vertical, vertical direction" generally refer to the direction of gravity, which is generally perpendicular to the ground, and "horizontal, horizontal plane direction" generally refers to the direction parallel to the ground; for ordinary technicians in this field, the specific meanings of the above terms in this specification can be understood according to specific circumstances.

[0053] The purpose of the present invention is to provide a hybrid electric vehicle oxygen sensor aging diagnosis method and system, so as to solve the problem that it is difficult to complete the front oxygen sensor aging diagnosis in plateau areas during actual use, resulting in the IUPR value failing to reach the statutory minimum value.

[0054] As can be understood by those skilled in the art, the oxygen sensor can transmit the oxygen content in the exhaust gas to the electronic control unit (ECU) of the engine, and control the air-fuel ratio of the engine near the theoretical air-fuel ratio through feedback, so that there will be no excess gasoline in the exhaust gas discharged by the car. However, when the car starts, the rapid preheating of the fuel vapor will cause the surface of the oxygen sensor to heat up rapidly, resulting in the peeling of the surface protective layer of the oxygen sensor due to the formation of carbon particles, and accelerating the aging of the oxygen sensor. Once there is a problem with the oxygen sensor, the air-fuel ratio cannot be controlled, which will lead to an increase in the fuel consumption and exhaust emissions of the car. In severe cases, there will be problems such as unstable engine idling, black smoke from the exhaust pipe, power reduction and increased fuel consumption. Therefore, it is necessary to maintain the frequency of oxygen sensor aging diagnosis; at the same time, the frequency of oxygen sensor aging diagnosis is also included in the IUPR numerator value. To ensure that the IUPR value meets the statutory minimum value, a certain frequency of oxygen sensor aging diagnosis should also be maintained. However, in high-altitude areas, oxygen sensor aging diagnosis is often unable to be performed due to excessive scavenging rate, which has a certain impact on maintaining the performance of the vehicle and meeting the statutory requirements. Based on this, the present application provides an oxygen sensor aging diagnosis method for a hybrid vehicle to ensure that the vehicle can perform the oxygen sensor aging diagnosis method at least once in high-altitude areas, thereby meeting the requirements for oxygen sensor aging diagnosis frequency of the vehicle in the full altitude range. It should be noted that this embodiment takes a hybrid vehicle with a scavenging function as an example, which does not mean that this application can only be used in hybrid vehicles. As long as the vehicle has a scavenging function and is equipped with an oxygen sensor, the present technical solution can be used, and this embodiment does not limit this.

[0055] Please refer to Figure 1 The present invention provides a method for diagnosing aging of an oxygen sensor of a hybrid vehicle, comprising:

[0056] Step S1: based on the altitude and the result of the scavenging rate test under the corresponding situation, a diagnostic working condition is selected;

[0057] Step S2: determining whether the current operating conditions of the vehicle meet the preset conditions for aging diagnosis;

[0058] Step S21: if satisfied, enter the aging diagnosis mode until the aging diagnosis is completed;

[0059] Step S22: If not, maintain normal operation and repeat the judgment until the current vehicle operating conditions meet the preset conditions and at least one aging diagnosis is completed during a single startup to shutdown process.

[0060] Furthermore, the aging diagnosis mode includes: the vehicle operates in a diagnostic condition, and the operating parameters of the vehicle's engine can enter the diagnostic interval multiple times; wherein, the time for which the vehicle maintains operation in the diagnostic condition meets a preset time, and the number of times the engine's operating parameters enter the diagnostic interval meets a preset number of times.

[0061] It should be noted that in step S1, since the scavenging rate is usually not greater than 2% in the oxygen sensor aging diagnosis, in this embodiment, 2% is used as the scavenging rate threshold. Taking the high altitude area with an altitude greater than the calibrated altitude as an example, the common working condition of the engine in the high altitude area is 1400 rpm to 3200 rpm, and the load is 40% to 90%. The scavenging rate test is performed under this working condition, and it is found that when the load is in the range of 40% to 55%, the scavenging rate is less than 2%. Therefore, 1400 rpm to 3200 rpm and the load of 40% to 55% can be selected as the diagnostic working condition. Of course, in the low altitude area with an altitude less than or equal to the calibrated altitude, the common working condition of the engine in the low altitude area should be selected for the scavenging rate test, and the appropriate working condition should be selected as the diagnostic working condition. In step S21, when it is determined that the current operating conditions of the vehicle meet the preset conditions for aging diagnosis, the vehicle enters the aging diagnosis mode, that is, the engine of the vehicle needs to keep running under the diagnostic condition for a preset time, and because the oxygen sensor aging diagnosis requires the engine to run multiple times in the diagnostic condition to complete, the number of times the engine's operating parameters (in this embodiment, it can be speed and load) enter the diagnostic interval (in this embodiment, it is the above-selected diagnostic condition) should also be limited. Among them, since the load in this article belongs to the medium load condition, the preset time should be determined according to the actual situation (such as road conditions, etc.), and the preset number should be determined in accordance with the requirements of ensuring that the oxygen sensor aging diagnosis is completed and does not affect normal driving. In other embodiments, the diagnostic condition can also be characterized by other operating parameters of the engine, and this embodiment does not limit this. At the same time, the specific aging diagnosis steps and results after entering the aging diagnosis mode can refer to the prior art, and this embodiment will not be repeated here.

[0062] With such configuration, by increasing the division of altitude, more stringent preset conditions are added in high-altitude areas, and repeated judgments are made to complete at least one oxygen sensor aging judgment, thereby avoiding the situation where the vehicle cannot perform aging diagnosis due to excessive scavenging rate in high-altitude areas. The IUPR numerator value can also be effectively improved so that the IUPR value meets regulatory requirements. At the same time, looser preset conditions are used in low-altitude areas, so that the vehicle can perform at least one oxygen sensor aging judgment in the entire altitude range from a single start to shutdown.

[0063] The following is a hybrid vehicle oxygen sensor aging diagnosis system to further illustrate the working principle of the aging diagnosis system when using the above aging diagnosis method.

[0064] Please refer to Figure 2 In an optional embodiment, the present invention further provides an oxygen sensor aging diagnosis system for a hybrid vehicle, comprising: a test module 100, a judgment module 200, a control module 300 and a measurement module 400. The test module 100 is used to select a diagnostic condition based on the altitude and the result of the scavenging rate test under the corresponding situation, and send the diagnostic condition to the control module 300. The diagnostic condition can be obtained by adding a judgment condition of the altitude and a screening condition for the scavenging rate test result to the existing scavenging rate test device. The judgment condition can be whether the altitude is greater than the calibration altitude, and the screening condition can be whether the scavenging rate is less than 2%. The structure and principle of the scavenging rate test device can refer to the prior art, and this embodiment will not repeat them. The judgment module 200 can be an ECU (Electronic Control Unit), which is used to receive the current vehicle operating conditions obtained by the measurement module 400, and judge whether the preset conditions for aging diagnosis are met, and send the judgment result to the control module 300. The control module 300 may be a VCU (Vehicle Control Unit), which is used to control the current vehicle to enter the aging diagnosis mode or maintain normal operation according to the judgment result; after the vehicle enters the aging diagnosis mode, the VCU needs to control the vehicle to maintain operation in the diagnostic condition for a preset time, and the number of times the engine's operating parameters enter the diagnostic interval meets the preset number of times, so as to ensure that an oxygen sensor aging diagnosis is completed. The measurement module 400 may be various sensors, such as temperature sensors, voltage sensors, etc., which are used to obtain the current operating conditions of the vehicle. At the same time, the test module 100 is connected to the control module 300 in communication, and the judgment module 200 is connected to the control module 300 and the measurement module 400 in communication, respectively, to realize information interaction between the modules.

[0065] Please refer to Figure 3 In an optional embodiment, the oxygen sensor aging diagnosis method for a hybrid vehicle may include the following steps:

[0066] Step S11: when the altitude is less than or equal to the calibrated altitude, the first diagnostic operating condition is selected in combination with the result of the scavenging rate test under the current situation;

[0067] Step S201: determining whether the current physical condition of the vehicle meets a first preset condition;

[0068] Step S202: determining whether the current vehicle has a condition that inhibits diagnosis;

[0069] Step S211: if the physical condition of the current vehicle meets the first preset condition, and there is no condition that inhibits diagnosis of the current vehicle, then enter the aging diagnosis mode until the aging diagnosis is completed;

[0070] Step S221: If the physical condition of the current vehicle does not meet the first preset condition or the current vehicle has a condition that inhibits diagnosis, maintain normal operation and repeat the judgment until the operating condition of the current vehicle meets the preset condition and completes at least one aging diagnosis in a single startup to shutdown process.

[0071] It should be noted that when the vehicle is in a low altitude area with an altitude less than or equal to the calibrated altitude, the scavenging rate is usually less than 2% in the normal working condition of the engine. Therefore, it is easier to meet the preset conditions for aging diagnosis than in high altitude areas. Therefore, in low altitude areas, the preset conditions for aging diagnosis are relatively simpler. It is only necessary to meet the first preset condition in step S201 and the absence of the condition that inhibits diagnosis in step S202. In an optional embodiment, the physical conditions of the current vehicle in step S201 may include the water temperature of the water tank, the voltage of the power supply, whether there is a priority operating condition, whether the signal of the oxygen sensor is reasonable, and whether the closed-loop control is within the target range; the first preset condition may be that the water temperature of the water tank is greater than 75°C. This step can be obtained by the temperature sensor set in the water tank and sent to the judgment module 200; the voltage of the battery is in the range of 11V to 14V. This step can be obtained by the voltage sensor and sent to the judgment module 200; whether there is a priority operating condition, whether the signal of the oxygen sensor is reasonable, Whether the closed-loop control is in the target range can be directly determined by the judgment module 200, wherein whether there is a priority condition can be directly determined by the logic in the judgment module 200. If there is a condition with a higher priority than the oxygen sensor aging diagnosis, the priority condition should be processed first; the signal of the oxygen sensor can be obtained by the oxygen sensor and sent to the judgment module 200. The judgment module 200 needs to judge the rationality of the oxygen sensor signal. If the signal is unreasonable, it means that the current oxygen sensor is damaged and no oxygen sensor aging diagnosis is required; whether the closed-loop control is in the target range means that the actual air-fuel ratio is near the target air-fuel ratio. In another optional embodiment, the conditions for inhibiting diagnosis in step S202 may include whether there is a protection mechanism for spare parts, whether there is an unexpected situation such as a misfire, etc. It should be noted that only when all the above-mentioned physical conditions and suppression diagnosis conditions meet the requirements, the judgment module 200 can determine that the current vehicle operating conditions meet the preset conditions for oxygen sensor aging diagnosis; at this time, the judgment module 200 will send the judgment result that meets the requirements to the control module 300, and the control module 300 controls the vehicle to enter the aging diagnosis mode until an aging diagnosis of the oxygen sensor is completed; if one of the physical conditions or the suppression diagnosis conditions does not meet the requirements, the judgment module 200 determines that the current vehicle operating conditions do not meet the preset conditions for oxygen sensor aging diagnosis. At this time, the control module 300 controls the vehicle to continue normal operation, but the judgment module 200 will continue to determine whether the current vehicle operating conditions meet the preset conditions for oxygen sensor aging diagnosis until an aging diagnosis of the oxygen sensor is completed.

[0072] Please refer to Figure 4 In another optional embodiment, the oxygen sensor aging diagnosis method for a hybrid vehicle may include the following steps:

[0073] Step S12: when the altitude is greater than the calibrated altitude, the second diagnostic operating condition is selected in combination with the result of the scavenging rate test under the current situation;

[0074] Step S201: determining whether the current physical condition of the vehicle meets a first preset condition;

[0075] Step S202: determining whether the current vehicle has a condition that inhibits diagnosis;

[0076] Step S203: determining whether the current power demand of the vehicle meets a second preset condition;

[0077] Step S204: determining whether the aging diagnosis of the oxygen sensor of the current vehicle has been completed once;

[0078] Step S212: if the physical condition of the current vehicle satisfies the first preset condition, the current vehicle does not have a condition to inhibit diagnosis, the power demand of the current vehicle satisfies the second preset condition, and the current vehicle has not completed the aging diagnosis of the oxygen sensor, then enter the aging diagnosis mode until the aging diagnosis is completed;

[0079] Step S222: If the physical condition of the current vehicle does not meet the first preset condition, the current vehicle has a condition that inhibits diagnosis, the power demand of the current vehicle does not meet the second preset condition, and the current vehicle has completed one of the aging diagnosis of the oxygen sensor, then maintain normal operation and repeat the judgment until the operating condition of the current vehicle meets the preset condition and at least one aging diagnosis is completed in a single startup to shutdown process.

[0080] It should be noted that when the vehicle is in a high altitude area with an altitude greater than the calibrated altitude, in the common working condition of the engine, the scavenging rate is usually greater than 2%, so it is relatively difficult to meet the preset conditions for aging diagnosis. Therefore, in high altitude areas, the preset conditions for aging diagnosis are relatively complex, and it is necessary to simultaneously meet the first preset condition in step S201, the condition that there is no inhibition diagnosis in step S202, the second preset condition in step S203, and the oxygen sensor aging diagnosis in step S204. In an optional embodiment, the conditions in steps S201 and S202 can refer to the above description, and this embodiment will not be repeated here; the power demand in step S203 includes: target torque change rate, vehicle speed change rate; the second preset condition can be that the target torque change rate and the vehicle speed change rate are both less than or equal to the corresponding threshold value, wherein the corresponding threshold value can be reasonably configured according to the actual road conditions and the current vehicle operation data, and this embodiment does not limit this. In another optional embodiment, whether the aging diagnosis of the oxygen sensor of the current vehicle is completed in step S204 is to ensure that the vehicle can complete at least one aging diagnosis of the oxygen sensor in high altitude areas. It should be noted that only when all the above physical conditions, inhibition diagnosis conditions, power requirements, and whether the aging diagnosis of the oxygen sensor is completed meet the requirements, the judgment module 200 can judge that the operating conditions of the current vehicle meet the preset conditions for the aging diagnosis of the oxygen sensor; at this time, the judgment module 200 will send the judgment result that meets the requirements to the control module 300, and the control module 300 controls the vehicle to enter the aging diagnosis mode until the aging diagnosis of the oxygen sensor is completed; if one of them does not meet the requirements, the judgment module 200 judges that the operating conditions of the current vehicle do not meet the preset conditions for the aging diagnosis of the oxygen sensor, and the control module 300 controls the vehicle to continue to operate normally, but the judgment module 200 will continue to judge whether the operating conditions of the current vehicle meet the preset conditions for the aging diagnosis of the oxygen sensor until the aging diagnosis of the oxygen sensor is completed.

[0081] In summary, in the oxygen sensor aging diagnosis method and system for a hybrid vehicle provided in an embodiment of the present invention, the oxygen sensor aging diagnosis method includes: selecting a diagnostic condition based on the altitude and in combination with the result of a scavenging rate test under corresponding circumstances; judging whether the current operating condition of the vehicle meets the preset condition for performing an aging diagnosis; if so, entering an aging diagnosis mode until the aging diagnosis is completed; if not, maintaining normal operation and repeating the judgment until the current operating condition of the vehicle meets the preset condition and performing an aging diagnosis at least once.

[0082] With such configuration, by increasing the division of altitude, more stringent preset conditions are added in high-altitude areas, and repeated judgments are made to complete at least one oxygen sensor aging judgment, thereby avoiding the situation where the vehicle cannot perform aging diagnosis due to excessive scavenging rate in high-altitude areas. The IUPR numerator value can also be effectively improved so that the IUPR value meets regulatory requirements. At the same time, looser preset conditions are used in low-altitude areas, so that the vehicle can perform at least one oxygen sensor aging judgment in the entire altitude range from a single start to shutdown.

[0083] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for diagnosing aging of an oxygen sensor of a hybrid vehicle, characterized in that: include: Based on the altitude, combined with the results of the scavenging rate test under the corresponding conditions, select the diagnostic operating condition; Determine whether the current operating conditions of the vehicle meet the preset conditions for aging diagnosis; If satisfied, then enter the aging diagnosis mode until the aging diagnosis is completed; If not, maintain normal operation and repeat the judgment until the current vehicle operating conditions meet the preset conditions and complete the aging diagnosis at least once in a single startup to shutdown process.

2. The method for diagnosing aging of an oxygen sensor of a hybrid vehicle according to claim 1, characterized in that: The aging diagnosis mode includes: The vehicle is running in the diagnostic condition, and the operating parameters of the engine of the vehicle can enter the diagnostic interval multiple times; The duration for which the vehicle maintains operation in the diagnostic condition satisfies a preset duration, and the number of times the operating parameters of the engine enter the diagnostic interval satisfies a preset number of times.

3. The method for diagnosing oxygen sensor aging in a hybrid vehicle according to claim 1, characterized in that: The scavenging rate of the diagnostic operating condition is less than a scavenging rate threshold.

4. The method for diagnosing oxygen sensor aging in a hybrid vehicle according to claim 1, wherein: The determining whether the current operating condition of the vehicle meets the preset condition for aging diagnosis includes: Determining whether the current physical condition of the vehicle meets the first preset condition; Determine whether the current vehicle has conditions that inhibit diagnosis.

5. The method for diagnosing oxygen sensor aging in a hybrid vehicle as claimed in claim 4, characterized in that: When the altitude is less than or equal to the calibrated altitude, if the physical condition of the current vehicle meets the first preset condition and there is no condition that inhibits diagnosis of the current vehicle, the aging diagnosis mode is entered until the aging diagnosis is completed.

6. The method for diagnosing aging of an oxygen sensor of a hybrid vehicle as claimed in claim 4, characterized in that: The physical conditions include: water temperature of the water tank, voltage of the power supply, whether there is a priority operating condition, whether the signal of the oxygen sensor is reasonable, and whether the closed-loop control is within the target range; When the water temperature of the water tank and the voltage of the power supply are within the corresponding preset ranges, there is no priority operating condition, the signal of the oxygen sensor is reasonable, and the closed-loop control is within the target range, it is determined that the current physical condition of the vehicle meets the first preset condition.

7. The method for diagnosing oxygen sensor aging in a hybrid vehicle as claimed in claim 4, characterized in that: The determining whether the current operating condition of the vehicle meets the preset condition for aging diagnosis also includes: Determining whether the current power demand of the vehicle meets a second preset condition; Determine whether the aging diagnosis of the oxygen sensor of the current vehicle has been completed once.

8. The method for diagnosing oxygen sensor aging in a hybrid vehicle as claimed in claim 7, characterized in that: When the altitude is greater than the calibrated altitude, if the physical condition of the current vehicle meets the first preset condition, the current vehicle does not have the condition to suppress diagnosis, the power demand of the current vehicle meets the second preset condition, and the current vehicle has not completed an aging diagnosis of the oxygen sensor, then the aging diagnosis mode is entered until the aging diagnosis is completed.

9. The method for diagnosing oxygen sensor aging in a hybrid vehicle as claimed in claim 7, characterized in that: The power demand includes: target torque change rate, vehicle speed change rate; When the target torque change rate and the vehicle speed change rate are both less than or equal to corresponding thresholds, it is determined that the current power demand of the vehicle meets the second preset condition.

10. An oxygen sensor aging diagnosis system for a hybrid vehicle, characterized in that: include: Testing module, judging module, controlling module and measuring module; The test module is used to select a diagnostic condition based on the altitude and the result of the scavenging rate test under the corresponding situation, and send the diagnostic condition to the control module; The judgment module is respectively connected to the control module and the measurement module for communication; The judgment module is used to receive the current vehicle operating conditions obtained by the measurement module, and judge whether the preset conditions for aging diagnosis are met; and send the judgment result to the control module; The control module controls the current vehicle to enter an aging diagnosis mode or maintain normal operation based on the judgment result.

11. The oxygen sensor aging diagnosis system for a hybrid vehicle as claimed in claim 10, characterized in that: The current vehicle operating conditions include: physical conditions, whether there are conditions that inhibit diagnosis, power requirements, and whether aging diagnosis of the oxygen sensor has been completed once.

12. The oxygen sensor aging diagnosis system for a hybrid vehicle as claimed in claim 11, characterized in that: The judgment module is configured to, when the altitude is less than or equal to the calibrated altitude, if the physical condition of the current vehicle meets the preset condition and there is no condition to inhibit diagnosis of the current vehicle, judge that the operating condition of the current vehicle meets the preset condition for performing aging diagnosis; The control module is configured to control the current vehicle to enter the aging diagnosis module when the operating condition of the current vehicle meets the preset condition for aging judgment.

13. The oxygen sensor aging diagnosis system for a hybrid vehicle as claimed in claim 11, characterized in that: The judgment module is configured to, when the altitude is greater than the calibrated altitude, determine that the operating conditions of the current vehicle meet the preset conditions for performing aging diagnosis if the physical conditions of the current vehicle meet the preset conditions, the current vehicle does not have conditions for inhibiting diagnosis, the power demand of the current vehicle meets the preset conditions, and the current vehicle has not completed an aging diagnosis of the oxygen sensor; The control module is configured to control the current vehicle to enter the aging diagnosis module when the operating condition of the current vehicle meets the preset condition for aging judgment.

14. The oxygen sensor aging diagnosis system for a hybrid vehicle as claimed in claim 10, characterized in that: The aging diagnosis mode includes: The vehicle is running in the diagnostic condition, and the operating parameters of the engine of the vehicle can enter the diagnostic interval multiple times; The duration for which the vehicle maintains operation in the diagnostic condition satisfies a preset duration, and the number of times the operating parameters of the engine enter the diagnostic interval satisfies a preset number of times.

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