Leakage diagnosis method and device of fuel evaporation system, storage medium and vehicle

Abstract

The invention is suitable for the technical field of automobiles, and provides a leakage diagnosis method and device of a fuel evaporation system, a storage medium and a vehicle. Wherein the fuel evaporation system comprises a fuel tank; the desorption pipeline comprises a first desorption pipeline; the carbon tank is connected with the oil tank through the first desorption pipeline; the leakage diagnosis method comprises the steps that the first oil tank pressure of the oil tank is obtained; the first oil tank pressure is compared with a first pressure threshold value, and a comparison result is obtained; according to the comparison result, a target test area is determined in multiple preset test areas, whether the vacuum degree of the target test area meets a preset attenuation condition or not is determined, and the multiple preset test areas comprise a first test area without the oil tank; and if the vacuum degree of the target test area meets the attenuation condition, determining that the fuel evaporation system leaks. According to the embodiment of the invention, the universality of leakage diagnosis can be improved.

Description

Technical Field

[0001] The present application belongs to the field of automobile technology, and in particular, relates to a leakage diagnosis method, device, storage medium and vehicle for a fuel evaporation system. Background Art

[0002] The fuel evaporation control (EVAP) system is used to prevent the fuel vapor in the fuel pipe from leaking into the atmosphere and polluting the environment. At the same time, it collects gasoline vapor and sends it to the intake pipe in time. After mixing with air, it enters the engine for combustion, thereby improving fuel economy. The current inherent fuel evaporation leakage diagnosis strategy of hybrid vehicles is implemented by using a leak diagnostic pump (Diagnostic Module Tank Leakage, DMTL). When the DMTL is working, it pumps air into the reference hole and the fuel tank, and detects whether the fuel evaporation system is leaking according to the pump current. This diagnostic method requires the configuration of a DMTL pump assembly, which has a high cost. Other diagnostic methods require diagnosis of the fuel tank. This method needs to be performed under the condition of a vehicle speed of 0. At this time, the engine running time increases due to waiting for the engine to enter the idle running state. Therefore, the current leakage diagnosis scheme of the fuel evaporation system is costly, needs to be implemented under specific working conditions, and has poor universality. Summary of the invention

[0003] The embodiments of the present application provide a fuel evaporation system leakage diagnosis method, device, computer-readable storage medium and vehicle, which can reduce costs, do not need to be implemented under the condition of a vehicle speed of 0, and can improve the universality of leakage diagnosis.

[0004] A first aspect of an embodiment of the present application provides a leakage diagnosis method for a fuel evaporation system, the fuel evaporation system comprising a fuel tank; a desorption pipeline, the desorption pipeline comprising a first desorption pipeline; a carbon canister connected to the fuel tank via the first desorption pipeline; the leakage diagnosis method comprising: obtaining a first fuel tank pressure of the fuel tank; comparing the first fuel tank pressure with a first pressure threshold to obtain a comparison result; based on the comparison result, determining a target test area from a plurality of preset test areas, the plurality of preset test areas at least including a first test area that does not include the fuel tank; determining whether a vacuum degree of the target test area meets a preset attenuation condition; if the vacuum degree of the target test area meets the attenuation condition, confirming that a leak occurs in the fuel evaporation system.

[0005] In some embodiments of the first aspect, the multiple preset test areas also include a second test area including the fuel tank; and determining a target test area among the multiple preset test areas based on the comparison result includes: if the first fuel tank pressure is greater than a first pressure threshold, determining the first test area as the target test area; if the first fuel tank pressure is less than or equal to the first pressure threshold, determining the second test area as the target test area.

[0006] In some embodiments of the first aspect, a fuel tank isolation valve is provided on the first desorption pipeline; the desorption pipeline also includes a second desorption pipeline arranged between the carbon canister and the engine, and a carbon canister solenoid valve is provided on the second desorption pipeline; when the target test area is the first test area, determining whether the vacuum degree of the target test area meets the preset attenuation condition includes: closing the fuel tank isolation valve and the carbon canister solenoid valve; after the fuel tank isolation valve and the carbon canister solenoid valve are closed, determining whether the vacuum degree of the target test area meets the attenuation condition.

[0007] In some embodiments of the first aspect, the desorption pipeline also includes a second desorption pipeline arranged between the carbon canister and the engine, and a carbon canister solenoid valve is arranged on the second desorption pipeline; when the target test area is a second test area including the fuel tank, determining whether the vacuum degree of the target test area meets the preset attenuation condition includes: closing the carbon canister solenoid valve; after the carbon canister solenoid valve is closed, determining whether the vacuum degree of the target test area meets the preset attenuation condition.

[0008] In some embodiments of the first aspect, before determining whether the vacuum degree of the target test area meets a preset attenuation condition, the leakage diagnosis method further includes: monitoring the state of the engine, the state of the fuel tank isolation valve and the vacuum degree of the area to be tested, the area to be tested including the carbon canister, the desorption pipeline and the fuel tank; when the engine is in a running state, the fuel tank isolation valve is in an open state, and the vacuum degree of the area to be tested is greater than a vacuum degree threshold, waiting for the second tank pressure of the fuel tank to be greater than a second pressure threshold.

[0009] In some embodiments of the first aspect, before monitoring the state of the engine, the state of the fuel tank isolation valve and the vacuum degree of the area to be tested, the leakage diagnosis method also includes: opening the fuel tank isolation valve; controlling the engine to enter an operating state, and desorbing the carbon canister.

[0010] In some embodiments of the first aspect, determining whether the vacuum degree of the target test area meets a preset attenuation condition includes: monitoring the vacuum degree of the target test area within a preset time period, and determining the vacuum degree attenuation slope of the target test area; if the vacuum degree attenuation slope is greater than a slope threshold, determining that the vacuum degree of the target test area meets the attenuation condition.

[0011] A second aspect of an embodiment of the present application provides a leakage diagnosis device for a fuel evaporation system, the fuel evaporation system comprising a fuel tank; a desorption pipeline, the desorption pipeline comprising a first desorption pipeline; a carbon canister connected to the fuel tank via the first desorption pipeline; the leakage diagnosis device comprising: a pressure acquisition unit, for acquiring a first fuel tank pressure of the fuel tank; a comparison unit, for comparing the first fuel tank pressure with a first pressure threshold to obtain a comparison result; a test area determination unit, for determining a target test area from a plurality of preset test areas according to the comparison result, the plurality of preset test areas comprising a first test area not including the fuel tank and a second test area including the fuel tank; an attenuation test unit, for determining whether a vacuum degree of the target test area meets a preset attenuation condition; and a leakage diagnosis unit, for confirming that a leakage occurs in the fuel evaporation system if the vacuum degree of the target test area meets the attenuation condition.

[0012] A third aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned fuel evaporation system leakage diagnosis method are implemented.

[0013] A fourth aspect of an embodiment of the present application provides a vehicle, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the vehicle comprises a fuel evaporation system, and the processor implements the steps of the above-mentioned fuel evaporation system leakage diagnosis method when executing the computer program.

[0014] A fifth aspect of an embodiment of the present application provides a computer program product. When the computer program product is run on a vehicle, the vehicle executes the above-mentioned fuel evaporation system leakage diagnosis method.

[0015] In an embodiment of the present application, a first tank pressure of the fuel tank is obtained, and a target test area is determined in multiple preset test areas based on a comparison result between the first tank pressure and a first pressure threshold. When the vacuum degree of the target test area satisfies an attenuation condition, it is confirmed that a fuel evaporation system is leaking. Since the multiple preset test areas include at least a first test area that does not contain a fuel tank, when performing a leak diagnosis on the first test area, the vacuum attenuation test process does not need to consider the problem of tank shaking caused by driving and thus affecting the leak diagnosis result. Therefore, it does not need to be performed under conditions where the vehicle speed is 0. At the same time, there is no need to set up a DMTL pump assembly, which helps to reduce costs. Therefore, the leakage diagnosis method provided in the present application can improve the universality of leakage diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art 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 creative labor.

[0017] Figure 1 It is a schematic diagram of the implementation flow of a leakage diagnosis method for a fuel evaporation system provided in an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of a first test area provided in an embodiment of the present application;

[0019] Figure 3 is a schematic diagram of a second test area provided in an embodiment of the present application;

[0020] Figure 4 is a schematic diagram of a second test area provided in an embodiment of the present application;

[0021] Figure 5 It is a schematic diagram of a specific implementation flow for preparing for a vacuum decay test provided in an embodiment of the present application;

[0022] Figure 6 It is a schematic diagram of the structure of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are protected by the present application.

[0024] The fuel evaporation system is used to prevent the fuel vapor in the fuel pipe from leaking into the atmosphere and polluting the environment. At the same time, it collects gasoline vapor and sends it to the intake pipe in time. After mixing with air, it enters the engine for combustion, improving fuel economy. The current inherent fuel evaporation leakage diagnosis strategy of hybrid vehicles is implemented using DMTL. When DMTL is working, it pumps air into the reference hole and the fuel tank, and detects whether the fuel evaporation system is leaking based on the pump current. This diagnostic method requires the configuration of a DMTL pump component, which is relatively expensive.

[0025] Other diagnostic methods require the fuel tank to be diagnosed, which needs to be done at a speed of 0, otherwise the tank will shake due to driving, which will affect the accuracy of the leak diagnosis results. This method will increase the engine running time because it waits for the engine to enter the idle running state.

[0026] Therefore, the current leakage diagnosis scheme for fuel evaporation system is costly, needs to be implemented under specific working conditions, and has poor universality.

[0027] In view of this, the present application proposes a leakage diagnosis method for a fuel evaporation system. There is no need to consider the problem of fuel tank shaking caused by driving and then affecting the leakage diagnosis results. Therefore, it is not necessary to perform the operation at a vehicle speed of 0. At the same time, there is no need to set up a DMTL pump assembly, which helps to reduce costs. Therefore, the leakage diagnosis method provided by the present application can improve the universality of leakage diagnosis.

[0028] It should be noted that the embodiments of the present application are completed based on the above findings and analysis. The above findings and analysis are not prior art, but should be regarded as part of the contribution of the present application to the prior art.

[0029] In order to illustrate the technical solution of the present application, a specific embodiment is provided below for illustration.

[0030] Figure 1 A schematic diagram of the implementation flow of a leakage diagnosis method for a fuel evaporation system provided in an embodiment of the present application is shown, and the method can be applied in a vehicle.

[0031] The above vehicles can be equipped with a fuel evaporation system. Please refer to Figure 2 The fuel evaporation system includes a fuel tank; a desorption pipeline, the desorption pipeline includes a first desorption pipeline; and a carbon canister connected to the fuel tank through the first desorption pipeline.

[0032] In some embodiments of the present application, a fuel tank isolation valve may be provided on the first desorption pipeline. When the fuel tank isolation valve is opened, the fuel vapor in the fuel tank can enter the carbon canister through the first desorption pipeline, and is absorbed and stored by the medium (usually activated carbon) in the carbon canister (this process is called "carbon canister adsorption"). When the fuel tank isolation valve is closed, the fuel tank and the carbon canister can be isolated.

[0033] In some other embodiments of the present application, the desorption pipeline may also include a second desorption pipeline arranged between the carbon canister and the engine, that is, the carbon canister is connected to the engine through the second desorption pipeline. A carbon canister solenoid valve is arranged on the second desorption pipeline. When the carbon canister solenoid valve is opened, the fuel vapor stored in the carbon canister can be transported to the engine (this process is called "carbon canister desorption"), so as to make full use of the fuel to achieve energy saving effect, and reduce the emission of pollutants into the atmosphere to achieve environmental protection effect. When the carbon canister solenoid valve is closed, the engine and the carbon canister can be isolated.

[0034] In some other embodiments of the present application, the desorption pipeline may further include a third desorption pipeline. The carbon canister is connected to the atmosphere through the third desorption pipeline. A ventilation magnetic valve may be provided on the third desorption pipeline. When the ventilation magnetic valve is opened, the third desorption pipeline is connected to the atmosphere. When the ventilation magnetic valve is closed, the third desorption pipeline can be isolated from the atmosphere.

[0035] In the embodiment of the present application, the fuel evaporation system is divided into zones. For ease of understanding, the fuel evaporation system may include multiple test zones, and the multiple test zones may include the first test zone. Figure 2 The dotted area, the first test area is also called a small space area, which is a test area without a fuel tank. The first test area may include a carbon canister and a desorption pipeline, for example, a carbon canister, a first desorption pipeline, a second desorption pipeline, and a third desorption pipeline.

[0036] The plurality of test areas may also include a second test area. Figure 3 The dotted area, the second test area is also called a large space area, which is a test area containing a fuel tank. The second test area may include a carbon canister, a desorption pipeline and a fuel tank, for example, a carbon canister, a fuel tank, a first desorption pipeline, a second desorption pipeline and a third desorption pipeline.

[0037] Specifically, the above-mentioned fuel evaporation system leakage diagnosis method may include the following steps S101 to S105.

[0038] Step S101, obtaining a first fuel tank pressure of a fuel tank.

[0039] The first fuel tank pressure may refer to the pressure inside the fuel tank when the vehicle is in a soaked state. The soaked state may refer to a state where the vehicle is stationary.

[0040] In some embodiments of the present application, a pressure sensor for monitoring the fuel tank pressure may be disposed on the fuel tank body, and the vehicle may obtain a first fuel tank pressure detected by the pressure sensor.

[0041] Step S102, comparing the first fuel tank pressure with the first pressure threshold to obtain a comparison result.

[0042] In some embodiments of the present application, the first pressure threshold can be used to determine the airtightness of the fuel tank. By comparing the first fuel tank pressure with the first pressure threshold, a comparison result is obtained, and the comparison result can reflect the necessity of performing a vacuum decay test on the fuel tank. Specifically, the fuel is volatile, and the fuel tank of the vehicle generates fuel pressure when the vehicle is immersed. If the first fuel tank pressure is greater than the first pressure threshold, it can be considered that the fuel tank is a closed space and there is no leakage. If the first fuel tank pressure is less than or equal to the first pressure threshold, it can be considered that there may be a leak in the fuel tank.

[0043] The first pressure threshold may be a preset fixed value or a non-fixed value, and the specific value may be set according to actual conditions.

[0044] In some embodiments of the present application, the first pressure threshold can be determined according to the vehicle immersion time and is positively correlated with the vehicle immersion time. The vehicle immersion time refers to the duration of time the vehicle is in the immersion state. The shorter the vehicle immersion time, the less fuel evaporates and the tank pressure is relatively small. Therefore, the first pressure threshold can be set lower. As the vehicle immersion time increases, the fuel evaporates more and the tank pressure increases. Therefore, the first pressure threshold can be set higher.

[0045] Step S103: determining a target test area from a plurality of preset test areas according to the comparison result.

[0046] In the embodiments of the present application, the target test area refers to an area where a vacuum decay test needs to be performed.

[0047] The plurality of preset test areas at least include a first test area without an oil tank, and in some embodiments, may also include a second test area with an oil tank. The specific composition of the first test area and the second test area may refer to the above description of Figure 2 , Figure 3 The description of this application will not be repeated here.

[0048] Step S104, determining whether the vacuum degree of the target test area meets a preset attenuation condition.

[0049] Step S105: If the vacuum degree of the target test area meets the attenuation condition, it is confirmed that the fuel evaporation system is leaking.

[0050] In the embodiments of the present application, vacuum refers to the rarefaction degree of the gas in a vacuum state, and the vacuum can be read by a pressure gauge or a vacuum gauge. By performing a decay test on the vacuum of the target test area, it can be determined whether the vacuum of the target test area meets the preset decay condition. The decay condition can be used to determine whether the decay rate of the vacuum of the target test area exceeds the normal level.

[0051] If the vacuum degree in the target test area meets the decay condition, it means that the vacuum degree in the target test area decays too fast, and it can be confirmed that the fuel evaporation system is leaking.

[0052] Correspondingly, if the vacuum degree of the target test area does not meet the decay condition, it means that the decay speed of the vacuum degree of the target test area is normal, and it can be confirmed that there is no leakage in the fuel evaporation system.

[0053] In an embodiment of the present application, a first tank pressure of the fuel tank is obtained, and a target test area is determined in multiple preset test areas based on a comparison result between the first tank pressure and a first pressure threshold. When the vacuum degree of the target test area satisfies an attenuation condition, it is confirmed that a fuel evaporation system is leaking. Since the multiple preset test areas include at least a first test area that does not contain a fuel tank, when performing a leak diagnosis on the first test area, the vacuum attenuation test process does not need to consider the problem of tank shaking caused by driving and thus affecting the leak diagnosis result. Therefore, it does not need to be performed under conditions where the vehicle speed is 0. At the same time, there is no need to set up a DMTL pump assembly, which helps to reduce costs. Therefore, the leakage diagnosis method provided in the present application can improve the universality of leakage diagnosis.

[0054] In some embodiments of the present application, determining a target test area from a plurality of preset test areas based on the comparison result may include: if the first tank pressure is greater than a first pressure threshold, determining the first test area as the target test area.

[0055] Specifically, if the first oil tank pressure is greater than the first pressure threshold, it means that the oil tank is a closed space and there is no leakage. Then the first test area can be determined as the target test area to determine whether the vacuum degree of the target test area meets the preset attenuation condition, that is, a vacuum attenuation test is performed on the aforementioned first test area.

[0056] Specifically, Figure 4 As shown, before determining whether the vacuum degree of the target test area meets the preset attenuation condition, the leakage diagnosis method may further include step S401 to step S402.

[0057] Step S401, monitoring the state of the engine, the state of the fuel tank isolation valve and the vacuum degree of the area to be tested.

[0058] The state of the engine may include a running state and a stopped state, and the vehicle may obtain the state of the engine based on the engine controller. The state of the fuel tank isolation valve may include an open state and a closed state. The vehicle may obtain the state of the fuel tank isolation valve based on the controller of the fuel evaporation system.

[0059] The area to be tested may include a carbon canister, a desorption pipeline and a fuel tank, and may cover the aforementioned first test area and second test area.

[0060] Specifically, in some embodiments of the present application, before monitoring the state of the engine, the state of the fuel tank isolation valve and the vacuum degree of the area to be tested, the leakage diagnosis method also includes: opening the fuel tank isolation valve, controlling the engine to enter the running state, and desorbing the carbon canister.

[0061] Specifically, when the engine is running and the fuel tank isolation valve is in the open state, the carbon canister will desorb. When the carbon canister desorbs, the fuel vapor in the fuel tank is sucked in (i.e., flows to the carbon canister through the first desorption pipeline). At this time, the vacuum degree of the fuel tank increases, and then the vacuum degree of the area to be tested increases.

[0062] It should be noted that, in the process of opening the oil tank isolation valve, the opening of the oil tank isolation valve can be directly opened to the target opening; or it can be opened slowly over a period of time, that is, the opening is opened at a specific change speed until the target opening is reached; thereby, the rising speed of the vacuum degree in the area to be tested can be controlled.

[0063] Step S402, when the engine is in operation, the tank isolation valve is in an open state, and the vacuum degree of the area to be tested is greater than a vacuum degree threshold, wait for the second tank pressure of the monitored tank to be greater than a second pressure threshold.

[0064] The second fuel tank pressure refers to the real-time pressure inside the fuel tank after the engine is in operation, the fuel tank isolation valve is in an open state, and the vacuum degree of the area to be tested is greater than the vacuum degree threshold. The method for obtaining the second fuel tank pressure can refer to the method for obtaining the first fuel tank pressure, and this application will not elaborate on it.

[0065] The second pressure threshold is greater than or equal to the first pressure threshold, and the specific value can be set according to actual conditions.

[0066] It can be understood that as the fuel vapor in the fuel tank is sucked out, the pressure inside the fuel tank gradually rises. When the second tank pressure is greater than the second pressure threshold, it means that the test requirements of the vacuum decay test are currently met. Then, it can be determined whether the vacuum degree of the target test area meets the preset decay conditions.

[0067] In some embodiments of the present application, when the target test area is the first test area, determining whether the vacuum degree of the target test area meets the preset attenuation condition may include: closing the fuel tank isolation valve and the carbon canister solenoid valve, and after the fuel tank isolation valve and the carbon canister solenoid valve are closed, determining whether the vacuum degree of the target test area meets the attenuation condition.

[0068] Specifically, if the system is in operation, the tank isolation valve is open, the vacuum of the area to be tested is greater than the vacuum threshold, and the tank reaches the second pressure threshold P2, the tank isolation valve can be closed, and the carbon canister solenoid valve can be closed, so that the first test area enters a closed state. At this time, a vacuum decay test is performed on the first test area to determine whether the vacuum of the target test area meets the decay condition, thereby determining whether there is a leak in the evaporation system.

[0069] Since the first test area does not include the fuel tank, there is no need to consider the problem of fuel tank shaking caused by driving and affecting the leakage diagnosis results. Therefore, the vacuum decay test process does not need to be performed at a vehicle speed of 0. Leakage diagnosis can also be performed while the vehicle is driving, which can improve the universality of leakage diagnosis.

[0070] Correspondingly, in some other embodiments of the present application, based on the comparison results, determining the target test area in multiple preset test areas may also include: if the first tank pressure is less than or equal to the first pressure threshold, then using the second test area as the target test area.

[0071] In an embodiment of the present application, if the first tank pressure is less than or equal to the first pressure threshold, indicating that there may be a leak in the tank, the second test area can be determined as the target test area to determine whether the vacuum degree of the target test area meets the preset attenuation condition, that is, a vacuum attenuation test is performed on the aforementioned second test area to obtain a leak diagnosis result.

[0072] Similarly, before determining whether the vacuum degree of the target test area meets the preset attenuation condition, the leakage diagnosis method may also include: monitoring the state of the engine, the state of the fuel tank isolation valve and the vacuum degree of the area to be tested; when the engine is in running state, the fuel tank isolation valve is in open state, and the vacuum degree of the area to be tested is greater than the vacuum degree threshold, waiting for the second tank pressure of the monitored tank to be greater than the second pressure threshold.

[0073] Specifically, when the target test area is the second test area including the fuel tank, determining whether the vacuum degree of the target test area meets the preset attenuation condition may include: closing the carbon canister solenoid valve, and after the carbon canister solenoid valve is closed, determining whether the vacuum degree of the target test area meets the preset attenuation condition.

[0074] Specifically, if the system is in operation, the tank isolation valve is open, the vacuum degree of the area to be tested is greater than the vacuum degree threshold, and the tank reaches the second pressure threshold P2, the carbon canister solenoid valve can be closed, and the tank isolation valve remains open, so that the second test area enters a closed state. At this time, a vacuum decay test is performed on the second test area to determine whether the vacuum degree of the target test area meets the decay condition, thereby determining whether there is a leak in the evaporation system.

[0075] In some embodiments of the present application, the above-mentioned determination of whether the vacuum degree of the target test area meets the preset attenuation condition may include: monitoring the vacuum degree of the target test area within a preset time period, and determining the vacuum degree attenuation slope of the target test area. If the vacuum degree attenuation slope is greater than the slope threshold, it is determined that the vacuum degree of the target test area meets the attenuation condition.

[0076] Specifically, whether the target test area is the first test area or the second test area, the vacuum degree of the target test area can be monitored within a preset time period to determine the vacuum degree decay slope of the target test area within the preset time period. The vacuum degree decay slope refers to the rate of change when the vacuum degree decreases.

[0077] When the airtightness of the fuel vapor system is good, the vacuum attenuation slope is small, or even 0. When the airtightness of the fuel vapor system deteriorates, the vacuum attenuation slope will increase significantly. Therefore, by setting the slope threshold, if the vacuum attenuation slope is greater than the slope threshold, it can be determined that the vacuum in the target test area meets the attenuation condition, and then confirm that the fuel evaporation system is leaking. If the vacuum attenuation slope is less than or equal to the slope threshold, it can be determined that the vacuum in the target test area does not meet the attenuation condition, and then confirm that the fuel evaporation system is not leaking.

[0078] Of course, in addition to using the vacuum attenuation slope, you can also analyze the mean, fluctuation and other parameters of the vacuum to determine whether the vacuum in the target test area meets the attenuation conditions, implement vacuum attenuation testing, and obtain leakage diagnosis results. This application does not impose any restrictions on this.

[0079] It should be noted that, for the sake of simplicity of description, the aforementioned method embodiments are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited to the described order of actions, because according to the present application, certain steps can be performed in other orders.

[0080] like Figure 5 FIG. 1 is a schematic structural diagram of a leakage diagnosis device 500 for a fuel evaporation system provided in an embodiment of the present application. The leakage diagnosis device 500 for a fuel evaporation system is configured in a vehicle.

[0081] Specifically, the leakage diagnosis device 500 of the fuel evaporation system may include:

[0082] A pressure acquisition unit 501, used to acquire a first fuel tank pressure of the fuel tank;

[0083] A comparing unit 502, configured to compare the first fuel tank pressure with a first pressure threshold to obtain a comparison result;

[0084] A test area determination unit 503, configured to determine a target test area from a plurality of preset test areas according to the comparison result, wherein the plurality of preset test areas include a first test area that does not include the fuel tank and a second test area that includes the fuel tank;

[0085] An attenuation test unit 504 is used to determine whether the vacuum degree of the target test area meets a preset attenuation condition;

[0086] The leakage diagnosis unit 505 is used to confirm that the fuel evaporation system leaks if the vacuum degree of the target test area meets the attenuation condition.

[0087] In some embodiments of the present application, the test area determination unit 503 may be specifically used to: if the first tank pressure is greater than a first pressure threshold, determine the first test area as a target test area; if the first tank pressure is less than or equal to the first pressure threshold, determine the second test area as a target test area.

[0088] In some embodiments of the present application, a fuel tank isolation valve is provided on the first desorption pipeline; the desorption pipeline also includes a second desorption pipeline arranged between the carbon canister and the engine, and a carbon canister solenoid valve is provided on the second desorption pipeline; the attenuation test unit 504 can be specifically used to: close the fuel tank isolation valve and the carbon canister solenoid valve; after the fuel tank isolation valve and the carbon canister solenoid valve are closed, determine whether the vacuum degree of the target test area meets the attenuation condition.

[0089] In some embodiments of the present application, the desorption pipeline also includes a second desorption pipeline arranged between the carbon canister and the engine, and a carbon canister solenoid valve is arranged on the second desorption pipeline; the attenuation test unit 504 can be specifically used to: close the carbon canister solenoid valve; after the carbon canister solenoid valve is closed, determine whether the vacuum degree of the target test area meets the preset attenuation condition.

[0090] In some embodiments of the present application, the attenuation test unit 504 can be specifically used to: monitor the state of the engine, the state of the fuel tank isolation valve and the vacuum degree of the area to be tested, the area to be tested includes the carbon canister, the desorption pipeline and the fuel tank; when the engine is in a running state, the fuel tank isolation valve is in an open state, and the vacuum degree of the area to be tested is greater than a vacuum degree threshold, wait for the second fuel tank pressure of the fuel tank to be greater than a second pressure threshold.

[0091] In some embodiments of the present application, the decay test unit 504 may be specifically used to: open the fuel tank isolation valve; control the engine to enter a running state, and desorb the carbon canister.

[0092] In some embodiments of the present application, the attenuation test unit 504 can be specifically used to: monitor the vacuum degree of the target test area within a preset time period, and determine the vacuum degree attenuation slope of the target test area; if the vacuum degree attenuation slope is greater than the slope threshold, it is determined that the vacuum degree of the target test area meets the attenuation condition.

[0093] It should be noted that, for the convenience and simplicity of description, the specific working process of the leakage diagnosis device 500 of the fuel evaporation system can be referred to Figures 1 to 4 The corresponding process of the method will not be repeated here.

[0094] like Figure 6 , which is a schematic diagram of a vehicle provided in an embodiment of the present application. Specifically, the vehicle 6 may include: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60, such as a leak diagnosis program for a fuel evaporation system. In addition, the vehicle may be equipped with a fuel evaporation system 63.

[0095] The processor 60 may be a vehicle controller and / or a controller of a fuel evaporation system.

[0096] When the processor 60 executes the computer program 62, the steps in the above-mentioned various fuel evaporation system leakage diagnosis method embodiments are implemented, for example: Figure 1 Alternatively, when the processor 60 executes the computer program 62, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 5 The functions of the pressure acquisition unit 501 , the comparison unit 502 , the test area determination unit 503 , the decay test unit 504 and the leakage diagnosis unit 505 are shown.

[0097] The computer program may be divided into one or more modules / units, which are stored in the memory 61 and executed by the processor 60 to complete the present application. The one or more modules / units may be a series of computer program instruction segments capable of completing specific functions, which are used to describe the execution process of the computer program in the vehicle.

[0098] For example, the computer program can be divided into: a pressure acquisition unit, a comparison unit, a test area determination unit, an attenuation test unit, and a leakage diagnosis unit. The specific functions of each unit are as follows: a pressure acquisition unit, used to acquire the first tank pressure of the fuel tank; a comparison unit, used to compare the first tank pressure with a first pressure threshold to obtain a comparison result; a test area determination unit, used to determine a target test area from a plurality of preset test areas according to the comparison result, wherein the plurality of preset test areas include a first test area that does not include the fuel tank and a second test area that includes the fuel tank; an attenuation test unit, used to determine whether the vacuum degree of the target test area meets a preset attenuation condition; and a leakage diagnosis unit, used to confirm that a leakage occurs in the fuel evaporation system if the vacuum degree of the target test area meets the attenuation condition.

[0099] The vehicle may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will appreciate that Figure 6 It is only an example of a vehicle and does not constitute a limitation of the vehicle. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the vehicle may also include input and output devices, network access devices, buses, etc.

[0100] The processor 60 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0101] The memory 61 may be an internal storage unit of the vehicle, such as a hard disk or memory of the vehicle. The memory 61 may also be an external storage device of the vehicle, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the vehicle. Further, the memory 61 may also include both an internal storage unit and an external storage device of the vehicle. The memory 61 is used to store the computer program and other programs and data required by the vehicle. The memory 61 may also be used to temporarily store data that has been output or is to be output.

[0102] It should be noted that, for the convenience and brevity of description, the structure of the above-mentioned vehicle can also refer to the specific description of the structure in the method embodiment, which will not be repeated here.

[0103] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0104] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0105] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0106] In the embodiments provided in the present application, it should be understood that the disclosed devices / vehicles and methods can be implemented in other ways. For example, the device / vehicle embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0107] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0109] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0110] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for diagnosing leakage of a fuel evaporation system, It is characterized in that The fuel evaporation system includes a fuel tank; a desorption pipeline, wherein the desorption pipeline includes a first desorption pipeline; and a carbon canister connected to the fuel tank via the first desorption pipeline. The leakage diagnosis method includes: obtaining a first fuel tank pressure of the fuel tank; Comparing the first fuel tank pressure with a first pressure threshold to obtain a comparison result; According to the comparison result, determining a target test area among a plurality of preset test areas, wherein the plurality of preset test areas at least includes a first test area that does not include the fuel tank; Determining whether the vacuum degree of the target test area meets a preset attenuation condition; If the vacuum degree of the target test area satisfies the attenuation condition, it is confirmed that the fuel evaporation system is leaking.

2. The method for diagnosing leakage of a fuel evaporation system according to claim 1, It is characterized in that The plurality of preset test areas also include a second test area including the fuel tank; and determining a target test area from the plurality of preset test areas according to the comparison result includes: If the first tank pressure is greater than a first pressure threshold, determining the first test area as a target test area; If the first tank pressure is less than or equal to a first pressure threshold, the second test area is determined as a target test area.

3. The method for diagnosing leakage of a fuel evaporation system according to claim 1, It is characterized in that The first desorption pipeline is provided with a fuel tank isolation valve; the desorption pipeline further comprises a second desorption pipeline provided between the carbon canister and the engine, and the second desorption pipeline is provided with a carbon canister solenoid valve; When the target test area is the first test area, determining whether the vacuum degree of the target test area meets a preset attenuation condition includes: Close the fuel tank isolation valve and the carbon canister solenoid valve; After the fuel tank isolation valve and the carbon canister solenoid valve are closed, it is determined whether the vacuum degree of the target test area meets the attenuation condition.

4. The method for diagnosing leakage of a fuel evaporation system according to claim 1, It is characterized in that The desorption pipeline further includes a second desorption pipeline disposed between the carbon canister and the engine, and a carbon canister solenoid valve is disposed on the second desorption pipeline; When the target test area is the second test area including the oil tank, determining whether the vacuum degree of the target test area meets a preset attenuation condition includes: closing the carbon canister solenoid valve; After the carbon canister solenoid valve is closed, it is determined whether the vacuum degree of the target test area meets the attenuation condition.

5. The method for diagnosing leakage of a fuel evaporation system according to any one of claims 1 to 4, It is characterized in that Before determining whether the vacuum degree of the target test area meets a preset attenuation condition, the leakage diagnosis method further includes: Monitoring the state of the engine, the state of the fuel tank isolation valve, and the vacuum degree of the area to be tested, wherein the area to be tested includes the carbon canister, the desorption pipeline, and the fuel tank; When the engine is in a running state, the fuel tank isolation valve is in an open state, and the vacuum degree of the area to be tested is greater than a vacuum degree threshold, wait for the second fuel tank pressure of the fuel tank to be greater than a second pressure threshold.

6. The method for diagnosing leakage of a fuel evaporation system according to claim 5, It is characterized in that Before monitoring the state of the engine, the state of the fuel tank isolation valve, and the vacuum degree of the area to be tested, the leakage diagnosis method further includes: Opening the oil tank isolation valve; The engine is controlled to enter a running state, and the carbon canister is desorbed.

7. The method for diagnosing leakage of a fuel evaporation system according to any one of claims 1 to 4, It is characterized in that The step of determining whether the vacuum degree of the target test area meets a preset attenuation condition includes: Monitoring the vacuum degree of the target test area within a preset time period, and determining a vacuum degree attenuation slope of the target test area; If the vacuum degree decay slope is greater than the slope threshold, it is determined that the vacuum degree of the target test area meets the decay condition.

8. A leakage diagnosis device for a fuel evaporation system, It is characterized in that The fuel evaporation system includes a fuel tank; a desorption pipeline, wherein the desorption pipeline includes a first desorption pipeline; a carbon canister connected to the fuel tank via the first desorption pipeline; and the leakage diagnosis device includes: a pressure acquisition unit, used for acquiring a first fuel tank pressure of the fuel tank; a comparing unit, configured to compare the first fuel tank pressure with a first pressure threshold to obtain a comparison result; a test area determination unit, configured to determine a target test area from a plurality of preset test areas according to the comparison result, wherein the plurality of preset test areas include a first test area that does not include the fuel tank and a second test area that includes the fuel tank; An attenuation test unit, used to determine whether the vacuum degree of the target test area meets a preset attenuation condition; The leakage diagnosis unit is used to confirm that the fuel evaporation system leaks if the vacuum degree of the target test area meets the attenuation condition.

9. A computer-readable storage medium storing a computer program. It is characterized in that When the computer program is executed by a processor, the steps of the fuel evaporation system leakage diagnosis method according to any one of claims 1 to 7 are implemented.

10. A vehicle comprising a memory, a processor and a computer program stored in the memory and executable on the processor, It is characterized in that The vehicle includes a fuel evaporation system, and the processor implements the steps of the fuel evaporation system leakage diagnosis method according to any one of claims 1 to 7 when executing the computer program.

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