Diagnostic method for evaporation leakage, electronic equipment and vehicle

Abstract

The invention relates to the technical field of vehicle fault diagnosis, and provides an evaporation leakage diagnosis method, electronic equipment and a vehicle, and the method comprises the steps: determining the diagnosis duration of pressure stability diagnosis according to the liquid level fluctuation value of an oil tank in each diagnosis period; and in the diagnosis duration, if the oil tank pressure of the oil tank meets the preset stability condition, based on the oil tank pressure, the evaporation leakage condition of the fuel evaporation system is diagnosed. By means of the method, misdiagnosis of evaporation leakage caused by pressure fluctuation of the oil tank under the special working condition can be avoided, and therefore the accuracy and reliability of diagnosis are improved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle fault diagnosis, and in particular to a method for diagnosing evaporative leakage, an electronic device and a vehicle. Background Art

[0002] The fuel evaporation system is used to capture the oil vapor in the vehicle's fuel tank and guide the oil vapor into the engine for combustion to prevent the oil vapor from being discharged into the atmosphere and causing environmental pollution. If there is a leak in the fuel evaporation system, the oil vapor may be directly discharged into the atmosphere, increasing air pollution and having a negative impact on the environment. In order to enhance environmental protection, it is necessary to diagnose the evaporation leakage of the fuel evaporation system.

[0003] In the process of realizing the diagnosis of evaporative leakage, the related technology is prone to misdiagnosis. For example, when the vehicle is in special working conditions (such as emergency braking, turning, etc.), the fluctuation of the oil in the fuel tank may interfere with the fuel tank pressure sensor signal, thereby causing misdiagnosis of evaporative leakage. Therefore, the diagnostic accuracy and reliability of this diagnostic method are not high. Summary of the invention

[0004] In view of this, the present application provides a diagnostic method, electronic device and vehicle for evaporative leakage, so as to solve the problem that the diagnostic method for evaporative leakage is prone to misdiagnosis, resulting in low diagnostic accuracy and reliability.

[0005] A first aspect of an embodiment of the present application provides a method for diagnosing evaporative leakage, which is applied to an electronic device in a vehicle, wherein the vehicle includes a fuel evaporative system, and the fuel evaporative system includes a fuel tank and a carbon canister solenoid valve. The method for diagnosing evaporative leakage includes: in each diagnostic cycle, determining a diagnostic duration according to a liquid level fluctuation value of the fuel tank; within the diagnostic duration, if the fuel tank pressure of the fuel tank meets a preset stability condition, diagnosing the evaporative leakage of the fuel evaporative system based on the fuel tank pressure.

[0006] In some embodiments, determining the diagnosis duration based on the liquid level fluctuation value of the fuel tank includes: detecting the liquid level fluctuation value of the fuel tank at preset time intervals within the driving cycle corresponding to each diagnostic period; obtaining all liquid level fluctuation values ​​before the current moment in response to a start instruction for pressure stability diagnosis; selecting a maximum liquid level fluctuation value from all the liquid level fluctuation values; determining a target compensation duration corresponding to the maximum liquid level fluctuation value based on a preset mapping relationship between liquid level fluctuation values ​​and compensation durations; and determining the diagnosis duration based on an initial duration and the target compensation duration.

[0007] In some embodiments, the method further includes: within the diagnostic duration, detecting the pressure fluctuation value of the fuel tank pressure at every first time interval; if within a second time interval, all pressure fluctuation values ​​are less than a preset value, determining that the fuel tank pressure meets the preset stability condition, and the second time interval is greater than the first time interval and less than the diagnostic duration; if within the second time interval, there is any pressure fluctuation value greater than the preset value, retiming the second time interval starting from the moment corresponding to any pressure fluctuation value; at the end of the diagnostic duration, if within the last retiming of the second time interval, there is a pressure fluctuation value greater than the preset value, determining that the fuel tank pressure does not meet the preset stability condition.

[0008] In some embodiments, the fuel evaporation system further includes a carbon canister, and the diagnosing the evaporation leakage of the fuel evaporation system based on the fuel tank pressure includes: closing the carbon canister solenoid valve and the carbon canister common valve, and diagnosing whether the carbon canister solenoid valve has a normally open leakage fault according to the fuel tank pressure; in the case that the carbon canister solenoid valve does not have a normally open leakage fault, calculating the rising gradient compensation value of the fuel tank pressure within a preset time period, and closing the carbon canister ventilation valve, opening the carbon canister solenoid valve based on a predetermined valve opening, and diagnosing whether the carbon canister solenoid valve has a normally closed leakage fault based on a flow integral of a flushing flow in the carbon canister and the fuel tank pressure; if the carbon canister solenoid valve does not have a normally closed leakage fault, closing the carbon canister ventilation valve, opening the carbon canister solenoid valve, and diagnosing whether the fuel evaporation system has a first leakage fault based on the flow integral and the fuel tank pressure; if the fuel evaporation system does not have a first leakage fault, closing the carbon canister ventilation valve and the carbon canister solenoid valve, and diagnosing whether the fuel evaporation system has a second leakage fault based on the rising gradient of the fuel tank pressure within the preset time period and the rising gradient compensation value.

[0009] In some embodiments, the method further includes: determining the predetermined valve opening based on a preset flushing flow rate corresponding to the carbon canister and an opening time of the carbon canister solenoid valve.

[0010] In some embodiments, the predetermined valve opening is determined based on the preset flushing flow corresponding to the carbon canister and the opening time of the carbon canister solenoid valve, including: determining the initial valve opening according to the preset flushing flow; opening the carbon canister solenoid valve according to the initial valve opening; determining the compensation valve opening according to the opening time of the carbon canister solenoid valve, the compensation valve opening being less than or equal to a preset opening threshold; determining the predetermined valve opening based on the initial valve opening and the compensation valve opening.

[0011] In some embodiments, the diagnosing whether the carbon canister solenoid valve has a normally-open leakage fault based on the fuel tank pressure includes: if within a first time period, the fuel tank pressure is less than a first pressure threshold, determining that the carbon canister solenoid valve has a normally-open leakage fault; if within the first time period, the fuel tank pressure is greater than or equal to the first pressure threshold, determining that the carbon canister solenoid valve does not have a normally-open leakage fault.

[0012] In some embodiments, the diagnosis of whether the carbon canister solenoid valve has a normally closed leakage fault based on the flow integral of the flushing flow in the carbon canister and the fuel tank pressure includes: when the flow integral accumulates to a first integral threshold, if the change in the fuel tank pressure is less than a preset change threshold, determining that the carbon canister solenoid valve has a normally closed leakage fault; if the change in the fuel tank pressure is greater than or equal to the preset change threshold, determining that the carbon canister solenoid valve does not have a normally closed leakage fault.

[0013] In some embodiments, the diagnosing whether the fuel evaporation system has a first leakage fault based on the flow integral and the fuel tank pressure includes: when the flow integral accumulates to a second integral threshold, if the fuel tank pressure is greater than a second pressure threshold, determining that the fuel evaporation system has a first leakage fault; if the fuel tank pressure is less than or equal to the second pressure threshold, determining that the fuel evaporation system does not have a first leakage fault.

[0014] In some embodiments, the diagnosing whether the fuel evaporation system has a second leakage fault based on the rising gradient of the fuel tank pressure within a preset time period and the rising gradient compensation value includes: calculating the rising gradient value of the fuel tank pressure within the preset time period according to the rising gradient and the rising gradient compensation value; if the rising gradient value is greater than a preset gradient threshold, determining that the fuel evaporation system has a second leakage fault; if the rising gradient value is less than or equal to the preset gradient threshold, determining that the fuel evaporation system does not have a second leakage fault.

[0015] In some embodiments, the fuel evaporation system also includes a carbon canister ventilation valve. Before determining the diagnosis duration based on the liquid level fluctuation value of the fuel tank, the method also includes: detecting a normally closed fault condition of the carbon canister ventilation valve based on the fuel tank pressure.

[0016] In some embodiments, the normally closed fault condition of the carbon canister ventilation valve is detected based on the fuel tank pressure, including: after flushing the carbon canister in the fuel evaporation system for a second time period, closing the carbon canister solenoid valve and opening the carbon canister ventilation valve; if within a third time period, the fuel tank pressure is greater than a third pressure threshold, determining that the carbon canister ventilation valve does not have a normally closed fault; if within the third time period, the fuel tank pressure is less than or equal to the third pressure threshold, determining that the carbon canister ventilation valve has a normally closed fault.

[0017] A second aspect of an embodiment of the present application provides an electronic device, including a memory, a processor, and computer-readable instructions stored in the memory, wherein the computer-readable instructions implement the above-mentioned evaporative leakage diagnosis method when executed by the processor.

[0018] A third aspect of an embodiment of the present application provides a vehicle, comprising the above-mentioned electronic device.

[0019] A fourth aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by a processor, the above-mentioned evaporative leakage diagnosis method is implemented.

[0020] In a method for diagnosing evaporative leakage provided in an embodiment of the present application, in each diagnostic cycle, the diagnostic duration of the pressure stability diagnosis is determined according to the liquid level fluctuation value of the fuel tank, so as to ensure that the evaporative leakage of the fuel evaporative system is diagnosed based on the fuel tank pressure when the fuel tank pressure is stable, thereby avoiding misdiagnosis of evaporative leakage due to fuel tank pressure fluctuations under special working conditions, thereby improving the accuracy and reliability of the diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 This is an application scenario diagram of the evaporative leakage diagnosis method provided in an embodiment of the present application.

[0023] Figure 2 is a structural example diagram of an evaporative leak diagnostic system provided in an embodiment of the present application.

[0024] Figure 3 It is a flow chart for implementing the method for diagnosing evaporative leakage provided in an embodiment of the present application.

[0025] Figure 4 This is another implementation flow chart of the evaporative leak diagnosis method provided in an embodiment of the present application.

[0026] Figure 5 It is a schematic diagram of the structure of the evaporative leakage diagnostic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by technicians in the technical field in this application. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. It should be understood that, unless otherwise specified in this application, " / " means or. For example, A / B can represent A or B. "And / or" in this application is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. "At least one" means one or more. "Multiple" means two or more than two. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c, a, b and c seven situations.

[0030] See also Figure 1 As shown in FIG. 1 , it is a device diagram of a method for diagnosing evaporative leakage provided in an embodiment of the present application. Figure 1As shown, the electronic device 100 includes a memory 101, at least one controller 102, at least one communication bus 103, at least one network interface 104 and other user interfaces 105. The controller 102 is used to implement the diagnostic method of evaporation leakage when executing the computer program stored in the memory 101, and at least one communication bus 103 is configured to realize the connection and communication between the memory 101 and at least one controller 102. The network interface 104 may include a wireless fidelity (Wireless Fidelity, Wi-Fi) interface, a 5G interface and other communication interfaces, and the user interface 105 may include a USB interface and other standard interfaces.

[0031] In some embodiments, a computer program is stored in the memory 101, and when the computer program is executed by at least one controller 102, all or part of the steps in the diagnostic method of evaporative leakage are implemented. Exemplarily, the computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory 101 and executed by the controller 102 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program in the vehicle.

[0032] In some embodiments, the memory 101 includes a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electronically erasable programmable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0033] In some embodiments, at least one controller 102 is the control core (ControlUnit) of the electronic device 100, and uses various interfaces and lines to connect various components of the entire electronic device 100, and executes various functions and processes data of the electronic device 100 by running or executing programs or modules stored in the memory 101, and calling data stored in the memory 101. For example, when at least one controller 102 executes the computer program stored in the memory, it implements all or part of the steps of the diagnostic method for evaporation leakage in the embodiment of the present application; or implements all or part of the functions of the alarm indicator processing device. At least one controller 102 can be composed of an integrated circuit, for example, it can be composed of a single packaged integrated circuit, or it can be composed of multiple integrated circuits with the same function or different functions, including one or more central controllers (Central Processing unit, CPU), microcontrollers, digital processing chips, graphic controllers, and combinations of various control chips.

[0034] In this embodiment, the electronic device 100 may be integrated in a vehicle. For example, the electronic device 100 may be an engine control unit (ECU) in a vehicle. The vehicle includes but is not limited to a gasoline vehicle, a hybrid vehicle, and the like.

[0035] Figure 1 The scenarios shown are only illustrative examples. The diagnostic method for evaporative leakage provided in the embodiments of the present application can also be applied to vehicles, vehicle-mounted devices, electronic devices that communicate with vehicles, etc. In other embodiments, the diagnostic method for evaporative leakage provided in the present application can also be applied in other scenarios. The embodiments of the present application do not limit the specific application scenarios of the diagnostic method for evaporative leakage. For the convenience of description, the following embodiments are described by taking the diagnostic method for evaporative leakage applied to electronic device 100 as an example.

[0036] It should be noted that other existing or future electronic products that are suitable for the present application should also be included in the protection scope of the present application and incorporated herein by reference.

[0037] See also Figure 2 FIG. 1 is a diagram showing an example of the system structure of an evaporative leakage diagnosis system provided in an embodiment of the present application, wherein the evaporative leakage diagnosis system includes a fuel evaporation system and an engine system.

[0038] like Figure 2 As shown, the fuel evaporation system includes the fuel tank, fuel tank pressure sensor, carbon canister, carbon canister ventilation valve, carbon canister solenoid valve, fuel cap, fuel pipe and other carbon canister related pipes (such as carbon canister adsorption pipe, carbon canister desorption pipe, high desorption pipe, low desorption pipe). The engine system includes the engine, intake manifold, turbocharger and throttle.

[0039] like Figure 2 As shown, the high desorption pipe of the fuel evaporation system is connected to the turbocharger and the throttle of the engine system. The high desorption pipe and the low desorption pipe are connected to the intake manifold of the engine system and connected to the engine through the intake manifold.

[0040] In some embodiments, the fuel tank is used to store fuel and generate oil vapor. The fuel tank pressure sensor is used to monitor the change of the fuel tank pressure in the fuel tank. The fuel cap is used to seal the fuel tank. The carbon canister is arranged between the fuel tank and the engine, and is used to adsorb and store oil vapor and reduce the emission of oil vapor. The carbon canister ventilation valve can be used to control the connection between the carbon canister and the atmosphere, balance the pressure inside and outside the carbon canister, and can also be used to allow external air to enter the carbon canister during the process of oil vapor being sucked into the engine for combustion, so as to ensure that the fuel vapor can be smoothly desorbed and sent to the engine for combustion. The carbon canister solenoid valve can be used to control the oil vapor to enter the engine for combustion. By controlling the opening and closing of the carbon canister solenoid valve, the communication or separation between the carbon canister and the engine can be controlled. Among them, by controlling the opening and closing degree of the carbon canister solenoid valve, the ability of the carbon canister to extract oil vapor from the fuel tank can be controlled. The high desorption tube is used to transport oil vapor to the engine under high load or high speed conditions. The low desorption tube is used to transport oil vapor to the engine under low load or idle conditions. The intake manifold introduces air (or a mixture of air and oil vapor) into the engine. Turbochargers are used to increase the intake pressure and increase the intake volume of the engine. They control the intake volume of the engine and adjust the power output of the engine. The high desorption tube can be connected with the turbocharger and the throttle valve to ensure that the oil vapor is introduced into the engine through the coordinated work of the turbocharger and the throttle valve.

[0041] In some embodiments, when the engine is running, the intake manifold will generate negative pressure (vacuum). In this case, if the carbon canister solenoid valve is opened, the oil vapor in the fuel tank will be sucked into the carbon canister through the adsorption pipeline between the fuel tank and the carbon canister based on the negative pressure generated by the intake manifold. The oil vapor adsorbed in the carbon canister will enter the intake manifold through the desorption pipeline between the carbon canister and the engine (such as the carbon canister desorption pipe, high desorption pipe, low desorption pipe), and then enter the engine through the intake manifold for combustion.

[0042] In some embodiments, during the process of drawing fuel vapor from the fuel tank into the canister, the tank pressure of the fuel tank will decrease.

[0043] Figure 2 The illustrated scenario is only an illustrative example. In other scenarios, the evaporation leakage system may also include other structures. The embodiments of the present application are not limited thereto.

[0044] See also Figure 3 The figure is a flowchart of the implementation of the evaporation leakage diagnosis method provided in the embodiment of the present application. The method is applied to electronic equipment. The embodiment of the present application is applied to the method in Figure 1The electronic device 100 in FIG. 1 is used as an example for explanation. The method includes the following steps. S11: In each diagnosis cycle, the diagnosis duration is determined according to the liquid level fluctuation value of the fuel tank.

[0045] In some embodiments, each diagnostic cycle may include a normally closed leakage diagnostic stage of a carbon canister ventilation valve, a pressure stability diagnostic stage of a fuel tank, a normally closed leakage diagnostic stage of a carbon canister solenoid valve, a normally open leakage diagnostic stage of a carbon canister solenoid valve, a large leakage diagnostic stage of a fuel evaporation system, a 1 mm small leakage diagnostic stage, etc. The embodiments of the present application do not limit the specific diagnostic stages.

[0046] In some embodiments, the oil (e.g., fuel) in the tank will slosh when the vehicle is moving, subjected to external forces, or under certain operating conditions (e.g., turning, braking, etc.), resulting in a change in the liquid level. The liquid level fluctuation value can be used to indicate the sloshing of the liquid in the tank.

[0047] In some embodiments, the diagnosis duration represents the maximum duration required for pressure stability diagnosis.

[0048] In some embodiments, according to the On-Board Diagnostics (OBD) regulations, the fuel evaporation system needs to be monitored or leak diagnosed, and the corresponding minimum In-UsePerformance Ratio or diagnostic frequency (IUPR) threshold is specified. Monitoring or leak diagnosis of the fuel evaporation system needs to ensure that the diagnosis meets the minimum IUPR requirements. In this case, if the diagnostic time of the pressure stability diagnosis is set to a long time, the pressure stability diagnosis may take too long, which may result in the failure to complete the leakage diagnosis of the fuel evaporation system within the driving cycle specified by the OBD regulations, and the failure to meet the IUPR requirements specified by the OBD regulations. In addition, due to the high requirements on the accuracy and layout of the fuel tank pressure sensor during the pressure stability diagnosis process, the signal of the fuel tank pressure sensor may fluctuate greatly when encountering special working conditions (such as emergency braking, turning, etc.). When the fuel tank pressure fluctuates greatly, the electronic device may exit the leakage diagnosis of the fuel evaporation system. In this case, if the diagnostic time of the pressure stability diagnosis is set to a short time, the electronic equipment may frequently exit the leakage diagnosis of the fuel evaporation system, which may result in the failure to complete the leakage diagnosis of the fuel evaporation system within the driving cycle specified by the OBD regulations and the failure to meet the IUPR requirements specified by the OBD regulations.

[0049] In addition, under special working conditions (such as emergency braking), the oil in the fuel tank fluctuates violently, which may cause the oil to enter the fuel pipe and oscillate repeatedly. In the case of sudden deceleration and parking, if the oil in the fuel pipe has not flowed back from the pipe to the fuel tank after parking, the oil is blocked at the connection between the fuel pipe and the fuel tank, then the fuel pipe will form a sealed space. In the process of the oil flowing back to the fuel tank, it will affect the signal value of the fuel tank pressure sensor installed on the fuel pipe close to the fuel tank (the detected fuel tank pressure), for example, causing the signal value of the installed fuel tank pressure sensor to show a downward trend. In this case, if the leakage diagnosis of the fuel evaporation system is performed, the signal value of the fuel tank pressure sensor may drop due to the fluctuation of the oil when diagnosing the normally open leakage fault of the carbon canister solenoid valve, and it may be mistakenly judged that the fuel tank pressure drops due to a certain opening of the carbon canister solenoid valve, thereby misjudging the fuel evaporation system. There is a normally open leakage fault of the carbon canister solenoid valve. In addition, the signal value of the fuel tank pressure sensor drops due to the fluctuation of the oil, which may also cause the calculated value of the rising gradient compensation value of the fuel tank pressure to be low. During the diagnosis of small leaks (e.g., 1mm small leaks), the calculation deviation of the rising gradient compensation value may cause the calculated value of the compensated rising gradient value to be too high. In this case, the electronic equipment may misjudge that there is a small leak in the fuel evaporation system.

[0050] In order to solve the above problems, the present application determines the diagnosis time according to the liquid level fluctuation value of the fuel tank. For example, in the case where the liquid level fluctuation of the fuel tank is large, the compensation time can be added on the basis of the initial time, and the diagnosis time is determined according to the initial time and the compensation time. Under normal driving conditions, the corresponding compensation time is short, and the impact on the overall fault diagnosis frequency is negligible, thereby ensuring the IUPR. The above method can effectively avoid the diagnosis time being set too long in normal driving (liquid level fluctuation is small), and the diagnosis time being set too short in special conditions (such as emergency braking, turning, etc.), which leads to the failure to complete the leakage diagnosis of the fuel evaporation system within the driving cycle specified by the OBD regulations, and the failure to meet the IUPR requirements specified by the OBD regulations.

[0051] In addition, in the embodiment of the present application, before performing the fault diagnosis of the carbon canister solenoid valve and the small leakage fault diagnosis of the fuel evaporation system, the fuel tank pressure stability diagnosis is performed, and the diagnosis time is determined according to the liquid level fluctuation value of the fuel tank. For example, in the case of large fluctuations in the liquid level of the fuel tank, the compensation time can be added on the basis of the initial time, and the diagnosis time is determined according to the initial time and the compensation time. Through the above method, after the fuel tank pressure is relatively stable, the fault diagnosis of the carbon canister solenoid valve and the small leakage fault diagnosis of the fuel evaporation system can be performed, thereby reducing the situation of misdiagnosis, improving the robustness, reliability and accuracy of the diagnosis, reducing the probability of false alarm faults of the fuel evaporation system of gasoline vehicles after sales, reducing after-sales complaints, and saving after-sales costs.

[0052] In some embodiments of the present application, the diagnosis duration is determined according to the liquid level fluctuation value of the fuel tank, including: detecting the liquid level fluctuation value of the fuel tank at preset time intervals within the driving cycle corresponding to each diagnosis period; obtaining all liquid level fluctuation values ​​before the current moment in response to the start instruction of the pressure stability diagnosis; selecting the maximum liquid level fluctuation value from all the liquid level fluctuation values; determining the target compensation time corresponding to the maximum liquid level fluctuation value according to the preset mapping relationship between the liquid level fluctuation value and the compensation time; and determining the diagnosis duration according to the initial time and the target compensation time.

[0053] In some embodiments, the preset time interval can be user-defined, for example, it can be set to 0.5s, 1s, etc. The embodiment of the present application does not limit the specific setting of the preset time interval.

[0054] In some embodiments, a driving cycle of a vehicle includes vehicle startup, vehicle driving, vehicle idling, and vehicle shutdown. Usually, when a vehicle enters an idling state after driving for a period of time, the electronic device can perform leakage diagnosis of the fuel evaporation system (e.g., diagnosis of fuel tank pressure stability, fault diagnosis of carbon canister solenoid valve, etc.). During the process of vehicle startup, driving, idling, and entering the pressure stability diagnosis stage, the electronic device can detect the level fluctuation value of the fuel tank at preset time intervals.

[0055] In other embodiments, the electronic device may also monitor the liquid level fluctuation value of the fuel tank in real time.

[0056] In some embodiments, the mapping relationship between the preset liquid level fluctuation value and the compensation time can be customized according to the specific structure of the fuel evaporation system, the material of the fuel tank and the fuel pipe, experience value, etc., or can be determined by performing multiple leak diagnosis tests on the same type of fuel evaporation system. The present application embodiment is not limited.

[0057] In some embodiments, the electronic device responds to a start instruction for pressure stability diagnosis and starts pressure stability diagnosis. The electronic device can obtain all liquid level fluctuation values ​​before the current moment (for example, from vehicle start, driving, idling to the current moment), select the maximum liquid level fluctuation value from all liquid level fluctuation values, and determine the target compensation duration corresponding to the maximum liquid level fluctuation value based on a preset mapping relationship between liquid level fluctuation values ​​and compensation durations. The electronic device determines the diagnosis duration based on the initial duration and the target compensation duration. For example, the initial duration and the target compensation duration are used as the diagnosis duration.

[0058] In some embodiments, the triggering method of the start instruction includes but is not limited to timing triggering, event triggering, etc. The embodiments of the present application are not limited to this.

[0059] In some embodiments, during the pressure stability diagnosis phase, the electronic device can control the carbon canister ventilation valve to open and close the carbon canister solenoid valve to allow the carbon canister to communicate with the outside atmosphere. In this case, in order to ensure that the carbon canister ventilation valve can be opened and to prevent the carbon canister ventilation valve failure from affecting the leakage diagnosis in other phases, the electronic device can detect the normally closed fault of the carbon canister ventilation valve based on the fuel tank pressure before the fuel tank pressure stability diagnosis or before determining the diagnosis time according to the fuel tank liquid level fluctuation value.

[0060] In some embodiments of the present application, the normally closed fault condition of the carbon canister ventilation valve is detected based on the fuel tank pressure, including: after flushing the carbon canister in the fuel evaporation system for a second time period, closing the carbon canister solenoid valve and opening the carbon canister ventilation valve; if within a third time period, the fuel tank pressure is greater than a third pressure threshold, determining that the carbon canister ventilation valve does not have a normally closed fault; if within the third time period, the fuel tank pressure is less than or equal to the third pressure threshold, determining that the carbon canister ventilation valve has a normally closed fault.

[0061] In some embodiments, the second duration, the third duration, the third pressure threshold, etc. can be custom calibrated based on historical diagnostic data, experience, etc., or can be determined by performing a large number of normally closed fault diagnostic tests on carbon canister ventilation valves. For example, the second duration can be set to 10s, 20s, etc. The third duration can be set to 5s, 6s, 7s, etc. The third pressure threshold can be set to, for example, -10hpa, etc. The embodiment of the present application does not limit the specific settings of the second duration, the third duration, and the third pressure threshold.

[0062] In some embodiments, flushing the carbon canister means the process of flushing the oil vapor stored in the carbon canister out and sending it to the engine for combustion by introducing air or negative pressure into the carbon canister. During the flushing process of the carbon canister, the oil vapor in the fuel tank will be extracted and sent to the engine for combustion, thereby reducing the pressure of the fuel tank. After flushing the carbon canister for a second time, the carbon canister solenoid valve is closed, and the carbon canister ventilation valve is opened to connect the carbon canister with the outside atmosphere. If the carbon canister ventilation valve does not have a normally closed fault, after opening the carbon canister ventilation valve, the fuel tank pressure will quickly recover to near atmospheric pressure. If the carbon canister ventilation valve has a normally closed fault, it will be difficult for the fuel tank pressure to recover to near atmospheric pressure when the carbon canister solenoid valve is closed. In this embodiment, the electronic device determines whether the carbon canister ventilation valve has a normally closed fault by judging whether the fuel tank pressure is greater than the third pressure threshold within the third time. Specifically, if within the third time period, the fuel tank pressure is greater than the third pressure threshold, it is determined that the carbon canister ventilation valve does not have a normally closed fault; if within the third time period, the fuel tank pressure is less than or equal to the third pressure threshold, it is determined that the carbon canister ventilation valve has a normally closed fault.

[0063] In some embodiments, if the carbon canister ventilation valve has a normally closed fault, the electronic device exits the fuel evaporative system leak diagnosis.

[0064] S12: Within the diagnosis time, if the fuel tank pressure of the fuel tank meets a preset stability condition, diagnose the evaporation leakage of the fuel evaporation system based on the fuel tank pressure.

[0065] In some embodiments, the preset stability condition is used to measure the stability of the fuel tank pressure. If the fuel tank pressure meets the preset stability condition, the electronic device can determine that the fuel tank pressure is stable. If the fuel tank pressure does not meet the preset stability condition, the electronic device can determine that the fuel tank pressure is unstable.

[0066] In some embodiments of the present application, during the diagnostic duration, the pressure fluctuation value of the fuel tank pressure is detected every first time interval; if during the second time interval, all pressure fluctuation values ​​are smaller than a preset value, it is determined that the fuel tank pressure meets the preset stability condition, and the second time interval is greater than the first time interval and smaller than the diagnostic duration; if during the second time interval, there is any pressure fluctuation value greater than the preset value, the second time interval is retimed from the moment corresponding to any pressure fluctuation value; at the end of the diagnostic duration, if during the last retimed second time interval, there is a pressure fluctuation value greater than the preset value, it is determined that the fuel tank pressure does not meet the preset stability condition.

[0067] In some embodiments, the first time interval, the second time interval, and the preset value can be customized according to historical diagnostic data, experience, etc. of the fuel evaporation system, or can be determined by performing multiple pressure stability diagnostic tests. For example, assuming that the diagnostic time is 15 seconds, the first time interval can be set to 1 second, the second time interval can be set to 3 seconds, and the preset value can be set to 0.2 hPa. The embodiments of the present application do not limit the specific settings.

[0068] In order to more clearly describe the process of determining the stability of the fuel tank pressure during the diagnosis period, an example will be described below.

[0069] As an example, it is assumed that the diagnosis starts from the 0th second, the diagnosis time is 15 seconds, the first time interval is 1 second, and the second time interval is 3 seconds. The pressure fluctuation value of the i-th second can be determined by calculating the difference between the fuel tank pressure of the i-th second and the fuel tank pressure of the 0th second. In this example, i is an integer, i is greater than 0, and less than or equal to 15. Starting from the diagnosis of the 0th second, count for 3 seconds and obtain the pressure fluctuation values ​​of the 1st to 3rd seconds. If all the pressure fluctuation values ​​of the 1st to 3rd seconds are less than the preset value, the electronic device can determine that the fuel tank pressure meets the preset stability condition, and the electronic device can enter the next stage of leakage diagnosis. If in the process of obtaining the pressure fluctuation values ​​of the 1st to 3rd seconds, a pressure fluctuation value greater than the preset value is obtained. For example, the pressure fluctuation value of the 1st second is less than the preset value, and the pressure fluctuation value of the 2nd second is greater than the preset value. In this case, the pressure fluctuation value of the 3rd to 5th seconds can be re-counted from the 2nd second for 3 seconds to obtain the pressure fluctuation value. If the pressure fluctuation values ​​of the 3rd to 5th seconds are all less than the preset value, the electronic device can determine that the fuel tank pressure meets the preset stability condition. If a pressure fluctuation value greater than the preset value is obtained during the process of obtaining the pressure fluctuation value from the 3rd to the 5th second. For example, the pressure fluctuation value of the 3rd second is greater than the preset value. In this case, the electronic device can re-count 3 seconds from the 3rd second to obtain the pressure fluctuation value from the 4th to the 6th second. Similarly, if there is still a pressure fluctuation value greater than the preset value within the last re-counted 3 seconds until the diagnosis time ends, then the electronic device will determine that the fuel tank pressure does not meet the preset stability condition. For example, the last re-counted 3 seconds is from the 13th to the 15th second. If the pressure fluctuation value of the 14th second is greater than the preset value, since the 15th second is the maximum duration of the pressure stability diagnosis, the electronic device can no longer re-count 3 seconds from the 14th second. Then, the 13th to the 15th second will be identified as the last re-counted 3 seconds. Since there is a pressure fluctuation value greater than the preset value within the last re-counted 3 seconds, the electronic device can determine that the fuel tank pressure does not meet the preset stability condition. Through this pressure stability judgment method, when it is determined that the fuel tank pressure meets the preset stability conditions, it is possible to promptly enter the next stage of evaporation leakage diagnosis (such as the normally open leakage fault diagnosis of the carbon canister solenoid valve, etc.), thereby helping to shorten the diagnosis cycle and improve diagnosis efficiency.

[0070] See also Figure 4 As shown, the process of diagnosing the evaporation leakage of the fuel evaporation system based on the fuel tank pressure includes steps S21 to S26, and the specific steps are as follows.

[0071] S21: Close the carbon canister solenoid valve and the carbon canister common valve, and diagnose whether the carbon canister solenoid valve has a normally open leakage fault based on the fuel tank pressure.

[0072] In some embodiments, during the process of diagnosing the normally open leakage fault of the carbon canister solenoid valve, the electronic device can close the carbon canister solenoid valve and the carbon canister common valve. In this case, if the carbon canister solenoid valve and the carbon canister ventilation valve are both in the closed state, the pressure change of the fuel tank will be very slow. However, if the carbon canister solenoid valve has a normally open leakage fault, then when the engine is started, the oil vapor is introduced into the engine through the carbon canister solenoid valve for combustion, and within a certain period of time, the fuel tank pressure will drop significantly.

[0073] In some embodiments of the present application, the carbon canister solenoid valve is diagnosed to have a normally open leakage fault based on the fuel tank pressure, including: if within a first time period, the fuel tank pressure is less than a first pressure threshold, it is determined that the carbon canister solenoid valve has a normally open leakage fault; if within the first time period, the fuel tank pressure is greater than or equal to the first pressure threshold, it is determined that the carbon canister solenoid valve does not have a normally open leakage fault.

[0074] In some embodiments, in order to facilitate more accurate diagnosis of the normally open leakage fault of the carbon canister solenoid valve, the electronic device can customize the first duration and the first pressure threshold according to historical diagnostic data, experience values, etc., or can determine the first duration and the first pressure threshold by performing multiple normally open leakage fault diagnostic tests of the carbon canister solenoid valve. The specific settings of the first duration and the first pressure threshold are not limited in the embodiments of the present application.

[0075] In some embodiments, in order to improve the accuracy of diagnosis, the electronic device can also start the engine during the diagnosis of the normally open leakage fault of the carbon canister solenoid valve. If the carbon canister solenoid valve has a normally open leakage fault, then when the engine is started, the oil vapor is introduced into the engine through the carbon canister solenoid valve for combustion, and within a certain period of time, the fuel tank pressure will drop significantly.

[0076] In some embodiments, if the carbon canister solenoid valve has a normally open leakage fault, the electronic device executes step S26.

[0077] S22: In the case that the carbon canister solenoid valve does not have a normally open leakage fault, calculate the rising gradient compensation value of the fuel tank pressure within a preset time period, close the carbon canister ventilation valve, open the carbon canister solenoid valve based on a predetermined valve opening, and diagnose whether the carbon canister solenoid valve has a normally closed leakage fault based on the flow integral of the flushing flow in the carbon canister and the fuel tank pressure.

[0078] In some embodiments, the rising gradient compensation value is used to correct pressure changes caused by factors such as incomplete system sealing performance and temperature changes.

[0079] In some embodiments, the electronic device can calculate the rising gradient compensation value of the fuel tank pressure within a preset time period based on the system historical data of the fuel evaporation system (such as fuel tank pressure change data) and environmental conditions (such as temperature, time, etc.) through an algorithm or model (such as a statistical regression model, a machine learning algorithm, a physical model, an empirical formula, etc.).

[0080] During the fault diagnosis of the normally closed leakage of the carbon canister solenoid valve, the electronic equipment can start the engine. When the engine is running, the intake manifold will generate negative pressure (vacuum). When the carbon canister solenoid valve is open, the fuel tank is connected to the intake manifold. Through the negative pressure of the intake manifold, the oil vapor in the fuel tank can be sucked into the engine for combustion.

[0081] In some embodiments, carbon canister flushing refers to a process of introducing oil vapor adsorbed or stored in the carbon canister into the engine for combustion.

[0082] In some embodiments, the flushing flow rate of the carbon canister indicates the amount of oil vapor passing through the carbon canister per unit time. The greater the flushing flow rate in the carbon canister, the faster the speed at which the oil tank pressure decreases.

[0083] In some embodiments, the flow integral of the flushing flow rate represents the cumulative value of the flushing flow rate within a certain period of time.

[0084] In some embodiments, the electronic device can indirectly or directly obtain information on the carbon canister flushing flow integral by monitoring the working status and parameter changes of the carbon canister, the carbon canister solenoid valve, the pressure sensor, etc. For example, by monitoring parameters such as the opening time of the carbon canister solenoid valve and the flushing flow through the carbon canister, the flow integral of the flushing flow in the carbon canister can be calculated.

[0085] In some embodiments, the longer the flushing flow accumulates, the greater the cumulative value of the flushing flow, and the greater the flow integral. In the case where the carbon canister solenoid valve does not have a normally closed leakage fault, there is a certain corresponding relationship between the fuel tank pressure and the flow integral of the carbon canister. In other words, as the flow integral of the flushing flow in the carbon canister increases, the more oil vapor in the fuel tank is extracted, and the smaller the fuel tank pressure in the fuel tank. If the carbon canister solenoid valve has a normally closed leakage fault, the oil vapor in the carbon canister may be introduced into the engine. As the flow integral of the flushing flow in the carbon canister increases, the fuel tank pressure may not drop or drop very little. Therefore, the electronic device can diagnose whether the carbon canister solenoid valve has a normally closed leakage fault based on the flow integral of the flushing flow in the carbon canister and the fuel tank pressure. For example, when the flow integral reaches a specified integral threshold, if the fuel tank pressure of the fuel tank does not drop to the fuel tank pressure corresponding to the specified integral threshold, the electronic device can determine that the carbon canister solenoid valve has a normally closed leakage fault.

[0086] In some embodiments of the present application, the predetermined valve opening is determined based on a preset flushing flow rate corresponding to the carbon canister and an opening time of the carbon canister solenoid valve.

[0087] In some embodiments, a predetermined valve opening is determined based on a preset flushing flow corresponding to the carbon canister and the opening time of the carbon canister solenoid valve, including: determining an initial valve opening according to the preset flushing flow; opening the carbon canister solenoid valve according to the initial valve opening; determining a compensation valve opening according to the opening time of the carbon canister solenoid valve; and determining a predetermined valve opening based on the initial valve opening and the compensation valve opening.

[0088] In some embodiments, the opening of the compensation valve is less than or equal to a preset opening threshold. The preset opening threshold represents the maximum limit of the opening of the compensation valve. The preset opening threshold can be customized based on experience, requirements of the fuel evaporation system, etc. For example, the preset opening threshold can be set to 5%, 6%, etc. The embodiment of the present application does not limit the setting method and specific setting of the preset opening threshold.

[0089] In this embodiment, the electronic device diagnoses the normally closed leakage fault of the carbon canister solenoid valve when the vehicle is idling. In this case, the flow accuracy requirement of the carbon canister solenoid valve is relatively high. If the flow accuracy of the carbon canister solenoid valve is not high at a small opening, then when the carbon canister solenoid valve is controlled to open a small opening, the actual opening of the carbon canister solenoid valve may be too small, or even the carbon canister solenoid valve is not actually opened, so that the oil vapor in the carbon canister cannot be introduced into the engine for combustion, and the fuel tank pressure will not drop. In this case, the electronic device is likely to misdiagnose the situation where the carbon canister solenoid valve is opened to a small opening as a normally closed leakage fault of the carbon canister solenoid valve.

[0090] In order to solve the above problems, the present application performs opening compensation on the carbon canister solenoid valve according to the opening time of the carbon canister solenoid valve during the diagnosis process of the normally closed leakage fault of the sight carbon canister solenoid valve. When the carbon canister solenoid valve is opened with a small opening, it is ensured that the carbon canister solenoid valve is in an open state, and the oil vapor can be introduced into the engine through the carbon canister solenoid valve for combustion, thereby overcoming the problem that the carbon canister solenoid valve is easily misdiagnosed as a normally closed leakage fault of the carbon canister solenoid valve due to the low flow accuracy of the carbon canister solenoid valve at a small opening. Among them, the compensation valve opening needs to be less than or equal to the preset opening threshold.

[0091] In some embodiments, the flushing flow of the carbon canister can also be expressed as the oil vapor flow through the carbon canister solenoid valve per unit time. The flushing flow of the carbon canister is directly related to the valve opening of the carbon canister solenoid valve. The larger the valve opening of the carbon canister solenoid valve, the larger the oil vapor flow through the carbon canister solenoid valve, and the flushing flow increases. The smaller the valve opening of the carbon canister solenoid valve, the smaller the oil vapor flow through the carbon canister solenoid valve, and the flushing flow decreases. When the valve of the carbon canister solenoid valve is closed, the oil vapor cannot be introduced into the engine through the carbon canister solenoid valve, and the flushing flow is zero. When the preset flushing flow is known, the electronic device can estimate the corresponding initial valve opening by consulting a data manual, establishing a mathematical model, using an empirical formula, or experimentally measuring.

[0092] In other embodiments, the initial valve opening may be preset, and the electronic device opens the carbon canister solenoid valve according to the initial valve opening.

[0093] In some embodiments, based on the initial valve opening, the electronic device can determine the compensation valve opening according to the opening time of the carbon canister solenoid valve, and perform opening compensation on the initial valve opening according to the compensation valve opening. The electronic device can use the sum of the compensation valve opening and the initial valve opening as the predetermined valve opening.

[0094] In some embodiments, the electronic device can be set to increase the compensation valve opening as the opening time increases, until the compensation valve opening reaches a preset valve threshold, and the electronic device stops compensating the valve opening. For example, after the electronic device opens the carbon canister solenoid valve according to the initial valve opening (for example, 5%), the compensation valve opening increases by 0.5% every 1 second, and the preset opening threshold is set to 5%. Then, starting from the opening of the carbon canister solenoid valve according to the initial valve opening of 5%, the compensation valve opening is 0.5% after the carbon canister solenoid valve is opened for 1 second, and the preset valve opening is 5.5%. After the carbon canister solenoid valve is opened for 2 seconds, the compensation valve opening is 1%, and the preset valve opening is 6%, until the compensation valve opening is 5% after the carbon canister solenoid valve is opened for 10 seconds, reaching the preset opening threshold, and the preset valve opening is 10%, at which time the electronic device stops compensating the valve opening.

[0095] In some embodiments of the present application, based on the flow integral of the flushing flow in the carbon canister and the fuel tank pressure, it is diagnosed whether the carbon canister solenoid valve has a normally closed leakage fault, including: when the flow integral accumulates to a first integral threshold, if the change in the fuel tank pressure is less than a preset change threshold, it is determined that the carbon canister solenoid valve has a normally closed leakage fault; if the change in the fuel tank pressure is greater than or equal to the preset change threshold, it is determined that the carbon canister solenoid valve does not have a normally closed leakage fault.

[0096] In some embodiments, the first integral threshold can be customized according to the diagnostic requirements. The embodiment of the present application does not limit the setting method and specific setting of the first integral threshold.

[0097] In some embodiments, the preset change threshold can be estimated based on the tank pressure under theoretical conditions corresponding to the first integral threshold and the tank pressure before the flow integral accumulation. If the carbon canister solenoid valve does not have a normally closed leakage fault, when the flow integral accumulates to the first integral threshold, the change in the tank pressure should be greater than or equal to the preset change threshold. If the carbon canister solenoid valve has a normally closed leakage fault, then when the flow integral accumulates to the first integral threshold, the tank pressure will be greater than the tank pressure under theoretical conditions, and the change in the tank pressure will be much smaller than the preset change threshold.

[0098] In some embodiments, since there is no normally closed leakage fault in the carbon canister solenoid valve, there is a certain corresponding relationship between the fuel tank pressure and the flow integral of the carbon canister. In other words, as the flow integral of the flushing flow in the carbon canister increases, the more oil vapor in the fuel tank is extracted, the smaller the fuel tank pressure in the fuel tank. If there is a normally closed leakage fault in the carbon canister solenoid valve, the oil vapor in the carbon canister may not be able to enter the engine. In this case, as the flow integral of the flushing flow in the carbon canister increases, the fuel tank pressure may not drop or drop very little. In this case, the electronic device can diagnose whether there is a normally closed leakage fault in the carbon canister solenoid valve by judging whether the change in the fuel tank pressure is less than the preset change threshold when the flow integral accumulates to the first integral threshold. If the change in the fuel tank pressure is less than the preset change threshold, it is determined that the carbon canister solenoid valve has a normally closed leakage fault; if the change in the fuel tank pressure is greater than or equal to the preset change threshold, it is determined that there is no normally closed leakage fault in the carbon canister solenoid valve.

[0099] In some embodiments, if the carbon canister solenoid valve has a normally closed leakage fault, the electronic device executes step S26.

[0100] S23: If the carbon canister solenoid valve does not have a normally closed leakage fault, close the carbon canister ventilation valve, open the carbon canister solenoid valve, and diagnose whether the fuel evaporation system has a first leakage fault based on the flow integral and the fuel tank pressure.

[0101] In some embodiments, the first leakage fault indicates a relatively large leakage fault that may be caused by a damaged solenoid valve, a damaged pipeline, a carbon canister fault, etc. A large leakage fault may cause unburned gasoline vapor to be directly discharged into the atmosphere, causing environmental pollution, exhaust odor, increased fuel consumption, and reduced vehicle power performance.

[0102] In some embodiments, during the process of diagnosing whether the fuel evaporation system has a first leakage fault, the electronic device can start the engine so that the intake manifold generates negative pressure. In this case, the electronic device closes the carbon canister ventilation valve and opens the carbon canister solenoid valve. Under the premise that the carbon canister solenoid valve does not have a normally closed leakage fault, if the fuel evaporation system does not have a first leakage fault, then under the negative pressure effect of the intake manifold, the fuel tank pressure will gradually decrease. If the fuel tank pressure decreases slightly, the fuel evaporation system may have a first leakage fault.

[0103] In some embodiments, based on the flow integral and the fuel tank pressure, diagnosing whether there is a first leakage fault in the fuel evaporation system includes: when the flow integral accumulates to a second integral threshold, if the fuel tank pressure is greater than the second pressure threshold, determining that the fuel evaporation system has a first leakage fault; if the fuel tank pressure is less than or equal to the second pressure threshold, determining that the fuel evaporation system does not have a first leakage fault.

[0104] In some embodiments, the second integral threshold can be customized according to the diagnostic requirements. The embodiment of the present application does not limit the setting method and specific setting of the second integral threshold.

[0105] In some embodiments, the electronic device may determine the second pressure threshold according to the tank pressure corresponding to the second integral threshold when the flow integral accumulates to the second integral threshold.

[0106] In some embodiments, under the premise that the carbon canister solenoid valve does not have a normally closed leakage fault, if the fuel evaporation system does not have a first leakage fault, then there will be a certain corresponding relationship between the fuel tank pressure and the flow integral of the carbon canister. In other words, as the flow integral of the flushing flow in the carbon canister increases, the more oil vapor in the fuel tank is extracted, the smaller the fuel tank pressure in the fuel tank will be. If the fuel evaporation system has a first leakage fault, as the flow integral of the flushing flow in the carbon canister increases, the fuel tank pressure may drop very little due to the influence of the external atmosphere, so that when the flow integral accumulates to the second integral threshold, the fuel tank pressure cannot drop to the fuel tank pressure corresponding to the second integral threshold. In this case, the electronic device determines the second pressure threshold according to the fuel tank pressure corresponding to the second integral threshold when the flow integral accumulates to the second integral threshold. The electronic device diagnoses whether the fuel evaporation system has a first leakage fault by detecting whether the fuel tank pressure is less than or equal to the second pressure threshold when the flow integral accumulates to the second integral threshold. When the flow integral accumulates to the second integral threshold, if the fuel tank pressure is greater than the second pressure threshold, the electronic device determines that the fuel evaporation system has a first leakage fault; if the fuel tank pressure is less than or equal to the second pressure threshold, the electronic device determines that the fuel evaporation system does not have a first leakage fault.

[0107] In some embodiments, if there is a first leakage fault in the fuel evaporation system, the electronic device executes step S26.

[0108] S24: If the fuel evaporation system does not have a first leakage fault, close the carbon canister ventilation valve and the carbon canister solenoid valve, and diagnose whether the fuel evaporation system has a second leakage fault based on the rising gradient of the fuel tank pressure within a preset time and the rising gradient compensation value.

[0109] In some embodiments, the second leakage fault indicates a minor leakage fault, such as a small leakage fault exceeding 1 mm, which may be caused by an abnormal gas cap seal, poor sealing at the pipe joint, or damage to the carbon canister and related components. Timely detection and handling of the second fault helps ensure the environmental performance and fuel economy of the vehicle. At the same time, it also helps to avoid environmental pollution and energy waste caused by leakage.

[0110] In some embodiments, when the carbon canister ventilation valve and the carbon canister solenoid valve are closed, the fuel evaporation system is in a sealed state, and the fuel tank pressure will gradually rise due to the evaporation of the fuel in the fuel tank. The electronic device can monitor the change of the fuel tank pressure through a sensor (such as a fuel tank pressure sensor), and thus calculate the rising gradient of the fuel tank pressure according to the change of the fuel tank pressure.

[0111] In some embodiments of the present application, based on the rising gradient of the fuel tank pressure within a preset time period and the rising gradient compensation value, diagnosing whether there is a second leakage fault in the fuel evaporation system includes: calculating the rising gradient value of the fuel tank pressure within the preset time period according to the rising gradient and the rising gradient compensation value; if the rising gradient value is greater than the preset gradient threshold, determining that the second leakage fault exists in the fuel evaporation system; if the rising gradient value is less than or equal to the preset gradient threshold, determining that the second leakage fault does not exist in the fuel evaporation system.

[0112] In some embodiments, the preset duration and the preset gradient threshold can be determined according to empirical formulas, relevant experimental data of the fuel evaporation system, etc. For example, the preset duration can be set to 3 seconds. The preset gradient threshold can be set to 0.6 hPa / s. The embodiment of the present application does not limit the setting method and specific settings of the preset duration and the preset gradient threshold.

[0113] In some embodiments, the electronic device can compensate for the rising gradient of the fuel tank pressure within the preset time length according to the rising gradient compensation value of the fuel tank pressure within the preset time length to obtain the rising gradient value of the fuel tank pressure within the preset time length. For example, the electronic device can calculate the rising gradient value of the fuel tank pressure within the preset time length by calculating the difference between the rising gradient and the rising gradient compensation value.

[0114] When the carbon canister ventilation valve and the carbon canister solenoid valve are closed, the fuel evaporation system is in a sealed state. Due to the evaporation of the fuel in the fuel tank, the fuel tank pressure will gradually rise, but the rise is slow. If the rising gradient value of the fuel tank pressure within the preset time is greater than the preset gradient threshold, it may indicate that there may be a second leakage fault in the fuel evaporation system, resulting in a faster rise in the fuel tank pressure due to the influence of the external atmosphere. If the rising gradient value is less than or equal to the preset gradient threshold, the electronic device determines that there is no second leakage fault in the fuel evaporation system.

[0115] In some embodiments, if there is a second leakage fault in the fuel evaporation system, the electronic device executes step S26.

[0116] S25: If the fuel evaporation system does not have the second leakage fault, determine that the evaporation system does not have evaporation leakage.

[0117] In some embodiments, if it is determined that there is no evaporative leak in the evaporative system, the electronic device may exit the diagnosis of the fuel evaporative leak.

[0118] S26: If the fuel evaporation system has any of the following faults: a normally open leakage fault of the carbon canister solenoid valve, a normally closed leakage fault of the carbon canister solenoid valve, a first leakage fault of the fuel evaporation system, and a second leakage fault of the fuel evaporation system, exit the evaporation leakage diagnosis.

[0119] In some embodiments, if the fuel evaporation system has any of the following faults: a normally open leakage fault of a carbon canister solenoid valve, a normally closed leakage fault of a carbon canister solenoid valve, a first leakage fault of the fuel evaporation system, and a second leakage fault of the fuel evaporation system, the electronic device may issue an alarm.

[0120] In some embodiments, the alarm prompt method includes but is not limited to voice prompt, text prompt, information notification, and alarm light prompt. This embodiment of the application is not limited to this.

[0121] In a method for diagnosing evaporative leakage provided in an embodiment of the present application, in each diagnostic cycle, the diagnostic duration of the pressure stability diagnosis is determined according to the liquid level fluctuation value of the fuel tank, so as to ensure that the evaporative leakage of the fuel evaporative system is diagnosed based on the fuel tank pressure when the fuel tank pressure is stable, thereby avoiding misdiagnosis of evaporative leakage due to fuel tank pressure fluctuations under special working conditions, thereby improving the accuracy and reliability of the diagnosis.

[0122] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0123] See also Figure 5 , Figure 5The structure diagram of the evaporation leakage diagnosis device provided in the embodiment of the present application is shown, which can realize the details of the evaporation leakage diagnosis method in the above embodiment and achieve the same effect. Figure 5 As shown, the evaporation leakage diagnostic device 10 can be applied to an electronic device with a data processing function. The evaporation leakage diagnostic device 10 includes: The determination module 11 is used to determine the diagnosis duration in each diagnosis cycle according to the liquid level fluctuation value of the fuel tank; the diagnosis module 12 is used to diagnose the evaporation leakage of the fuel evaporation system based on the fuel tank pressure if the fuel tank pressure meets the preset stability condition within the diagnosis duration.

[0124] The specific definition of the diagnostic device 10 for evaporative leakage can refer to the definition of the diagnostic method for evaporative leakage in the above text, which will not be repeated here. Each module in the diagnostic device 10 for evaporative leakage can be implemented in whole or in part by software, hardware and a combination thereof. The above modules can be embedded in or independent of the processor in the electronic device in the form of hardware, or can be stored in the memory of the electronic device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0125] The embodiment of the present application also provides a vehicle, comprising the above electronic device. The vehicle includes but is not limited to a gasoline vehicle and a hybrid vehicle.

[0126] An embodiment of the present application further provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program includes program instructions. The method implemented when the program instructions are executed can refer to the diagnostic method of evaporative leakage in the above-mentioned embodiments of the present application. The computer-readable storage medium may be an internal memory of the electronic device of the above-mentioned embodiment, such as a hard disk or memory of the electronic device. The computer-readable storage medium may also be an external storage device of the electronic device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Furthermore, the computer-readable storage medium may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function, etc.; the data storage area may store data created according to the use of the electronic device, etc.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A method for diagnosing evaporative leakage, applied to an electronic device in a vehicle, characterized in that: The vehicle includes a fuel evaporation system, the fuel evaporation system includes a fuel tank and a carbon canister solenoid valve, and the evaporation leakage diagnosis method includes: In each diagnosis cycle, determining the diagnosis duration according to the liquid level fluctuation value of the oil tank; During the diagnosis time, if the fuel tank pressure of the fuel tank meets a preset stability condition, the evaporation leakage of the fuel evaporation system is diagnosed based on the fuel tank pressure.

2. The method for diagnosing evaporative leakage according to claim 1, characterized in that: The step of determining the diagnosis duration according to the liquid level fluctuation value of the oil tank includes: In the driving cycle corresponding to each diagnostic period, detecting the liquid level fluctuation value of the fuel tank at every preset time interval; In response to a start instruction of the pressure stability diagnosis, all liquid level fluctuation values ​​before the current moment are obtained; Selecting a maximum liquid level fluctuation value from all the liquid level fluctuation values; Determine the target compensation time corresponding to the maximum liquid level fluctuation value according to the preset mapping relationship between the liquid level fluctuation value and the compensation time; The diagnosis duration is determined according to the initial duration and the target compensation duration.

3. The method for diagnosing evaporative leakage according to claim 1, characterized in that: The method further comprises: During the diagnosis time, detecting the pressure fluctuation value of the fuel tank pressure at every first time interval; If within the second time interval, all pressure fluctuation values ​​are less than the preset value, it is determined that the tank pressure meets the preset stability condition, and the second time interval is greater than the first time interval and less than the diagnosis duration; If any pressure fluctuation value exists within the second time interval and is greater than the preset value, the second time interval is re-timed from the moment corresponding to the any pressure fluctuation value; At the end of the diagnosis time, if there is a pressure fluctuation value greater than the preset value in the second time interval of the last re-timing, it is determined that the tank pressure does not meet the preset stability condition.

4. The method for diagnosing evaporative leakage according to claim 1, characterized in that: The fuel evaporation system further includes a carbon canister, and the diagnosing of evaporation leakage of the fuel evaporation system based on the fuel tank pressure includes: closing the carbon canister solenoid valve and the carbon canister common valve, and diagnosing whether the carbon canister solenoid valve has a normally open leakage fault according to the fuel tank pressure; Under the condition that the carbon canister solenoid valve does not have a normally open leakage fault, calculating the rising gradient compensation value of the fuel tank pressure within a preset time period, closing the carbon canister ventilation valve, opening the carbon canister solenoid valve based on a predetermined valve opening, and diagnosing whether the carbon canister solenoid valve has a normally closed leakage fault based on the flow integral of the flushing flow in the carbon canister and the fuel tank pressure; If the carbon canister solenoid valve does not have a normally closed leakage fault, closing the carbon canister ventilation valve, opening the carbon canister solenoid valve, and diagnosing whether the fuel evaporation system has a first leakage fault based on the flow integral and the fuel tank pressure; If the fuel evaporation system does not have a first leakage fault, the carbon canister ventilation valve and the carbon canister solenoid valve are closed, and based on the rising gradient of the fuel tank pressure within the preset time period and the rising gradient compensation value, it is diagnosed whether the fuel evaporation system has a second leakage fault.

5. The method for diagnosing evaporative leakage according to claim 4, characterized in that: The method further comprises: The predetermined valve opening is determined based on a preset flushing flow rate corresponding to the carbon canister and an opening time of the carbon canister solenoid valve.

6. The method for diagnosing evaporative leakage according to claim 5, characterized in that: The determining the predetermined valve opening based on the preset flushing flow rate corresponding to the carbon canister and the opening time of the carbon canister solenoid valve includes: Determining an initial valve opening according to the preset flushing flow rate; opening the carbon canister solenoid valve according to the initial valve opening; Determining a compensation valve opening according to the opening time of the carbon canister solenoid valve, wherein the compensation valve opening is less than or equal to a preset opening threshold; The predetermined valve opening is determined based on the initial valve opening and the compensation valve opening.

7. The method for diagnosing evaporative leakage according to claim 4, characterized in that: The diagnosing, according to the fuel tank pressure, whether the carbon canister solenoid valve has a normally open leakage fault comprises: If the fuel tank pressure is less than a first pressure threshold within a first time period, it is determined that the carbon canister solenoid valve has a normally open leakage fault; If the fuel tank pressure is greater than or equal to a first pressure threshold within the first time period, it is determined that there is no normally open leakage fault in the carbon canister solenoid valve.

8. The method for diagnosing evaporative leakage according to claim 4, characterized in that: The diagnosing whether the carbon canister solenoid valve has a normally closed leakage fault based on the flow integral of the flushing flow in the carbon canister and the fuel tank pressure includes: When the flow integral accumulates to a first integral threshold, if the change in the fuel tank pressure is less than a preset change threshold, it is determined that the carbon canister solenoid valve has a normally closed leakage fault; If the change in the fuel tank pressure is greater than or equal to the preset change threshold, it is determined that there is no normally closed leakage fault in the carbon canister solenoid valve.

9. The method for diagnosing evaporative leakage according to claim 4, characterized in that: The diagnosing whether the fuel evaporation system has a first leakage fault based on the flow integral and the fuel tank pressure includes: When the flow integral accumulates to a second integral threshold, if the fuel tank pressure is greater than a second pressure threshold, it is determined that a first leakage fault exists in the fuel evaporation system; If the fuel tank pressure is less than or equal to the second pressure threshold, it is determined that the fuel evaporation system does not have a first leakage fault.

10. The method for diagnosing evaporative leakage according to claim 4, characterized in that: The diagnosing whether the fuel evaporation system has a second leakage fault based on the rising gradient of the fuel tank pressure within a preset time and the rising gradient compensation value includes: Calculating the rising gradient value of the fuel tank pressure within the preset time period according to the rising gradient and the rising gradient compensation value; If the rising gradient value is greater than a preset gradient threshold, it is determined that a second leakage fault exists in the fuel evaporation system; If the rising gradient value is less than or equal to the preset gradient threshold, it is determined that the fuel evaporation system does not have a second leakage fault.

11. The method for diagnosing evaporative leakage according to claim 1, characterized in that: The fuel evaporation system further includes a carbon canister ventilation valve. Before determining the diagnosis duration according to the liquid level fluctuation value of the fuel tank, the method further includes: Based on the fuel tank pressure, a normally closed fault condition of the carbon canister ventilation valve is detected.

12. The method for diagnosing evaporative leakage according to claim 11, characterized in that: The detecting the normally closed fault condition of the carbon canister ventilation valve based on the fuel tank pressure includes: After flushing the carbon canister in the fuel evaporation system for a second time period, closing the carbon canister solenoid valve and opening the carbon canister ventilation valve; If the fuel tank pressure is greater than a third pressure threshold within a third time period, it is determined that the carbon canister ventilation valve does not have a normally closed fault; If the fuel tank pressure is less than or equal to the third pressure threshold within the third time period, it is determined that the carbon canister ventilation valve has a normally closed fault.

13. An electronic device, characterized in that: The electronic device comprises a memory, a processor and computer-readable instructions stored in the memory, and the computer-readable instructions, when executed by the processor, implement the method for diagnosing evaporative leakage according to any one of claims 1 to 12.

14. A vehicle, characterized in that: The vehicle includes the electronic device as claimed in claim 13.

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