Leak diagnosis system, method, device and vehicle for a fuel vapor system

Abstract

The application relates to a leakage diagnosis system, method and device of a fuel evaporation system and a vehicle, wherein the leakage diagnosis system comprises an oil tank, a first pipeline, a second pipeline, a third pipeline, a controller and an engine, a generator, a carbon canister, a carbon canister electromagnetic valve and a throttle valve which are respectively connected with the controller; one end of the first pipeline is communicated with an air intake manifold of the engine, the other end of the first pipeline is used for being communicated with the second pipeline or the third pipeline, the first pipeline is provided with the carbon canister electromagnetic valve and a pressure detection part, the carbon canister electromagnetic valve is located between the air intake manifold and the pressure detection part; the second pipeline is communicated with the carbon canister and the oil tank, and the carbon canister is further provided with a breather valve; the third pipeline is provided with a reference hole with a preset aperture. Through the leakage diagnosis of the fuel evaporation system, the development efficiency can be improved, the overall structure can be simplified, and the cost can be reduced while ensuring the diagnosis accuracy.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to a leak diagnosis system, method, apparatus, and vehicle for a fuel evaporation system. Background Technology

[0002] With the increasing number of cars on the road, vehicle pollution has become a significant source of air pollution, a major cause of fine particulate matter and photochemical smog. When a vehicle's fuel evaporation system leaks, fuel vapors enter the air, causing air pollution. Therefore, it is necessary to check whether the vehicle's fuel evaporation system has leaks exceeding the permissible range.

[0003] In existing technologies, leak diagnosis of fuel evaporation systems mainly involves setting up a pump to evacuate the fuel evaporation system, then sealing the system, and using a pressure sensor to measure the slope of the vacuum drop to determine whether the system has reached a leakage level of 1 mm.

[0004] However, to ensure accuracy, this diagnostic method requires extensive preliminary testing to determine the vacuum drop rate under different conditions (such as ambient temperature and fuel tank level) and varying degrees of leakage. This results in a large workload and low development efficiency. Furthermore, the need to install a pump to vacuum the fuel evaporation system leads to a complex overall structure and higher costs.

[0005] Therefore, how to ensure the accuracy of leak diagnosis in fuel evaporation systems while improving development efficiency, simplifying the overall structure, and reducing costs is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this application is to provide a leak diagnosis system, method, apparatus and vehicle for fuel evaporation systems, which can ensure the accuracy of the diagnosis while improving development efficiency, simplifying the overall structure and reducing costs when diagnosing leaks in fuel evaporation systems.

[0007] To address the aforementioned technical problems, this application provides a fuel evaporation system, comprising a fuel tank, a first pipeline, a second pipeline, a third pipeline, a controller, and an engine, a generator, a carbon canister, a carbon canister solenoid valve, and a throttle valve, all signal-connected to the controller. One end of the first pipeline is connected to the intake manifold of the engine, and the other end of the first pipeline is used to connect to either the second or the third pipeline. The first pipeline is equipped with a carbon canister solenoid valve and a pressure detection unit, with the carbon canister solenoid valve located between the intake manifold and the pressure detection unit. The second pipeline connects the carbon canister and the fuel tank, and the carbon canister is also equipped with a vent valve. The third pipeline is equipped with a reference hole of a preset diameter.

[0008] Optionally, it also includes a three-way valve, which has a first port, a second port and a third port, wherein the first port is connected to the second pipeline, the second port is connected to the third pipeline, and the third port is connected to the first pipeline, and the third port is used to connect to the first port or the second port.

[0009] Optionally, a first filter device is also provided at the reference hole.

[0010] Optionally, the preset aperture is 0.5mm-1mm.

[0011] This application also provides a method for diagnosing leaks in a fuel evaporation system. Based on the aforementioned fuel evaporation system leak diagnosis system, the method for diagnosing leaks in a fuel evaporation system includes the following steps:

[0012] The engine is controlled to stop injecting fuel, and the generator drives the engine to idle at a preset speed.

[0013] Adjust the opening of the carbon canister solenoid valve and the throttle valve to bring the vacuum level of the intake manifold to the preset vacuum level.

[0014] Close the ventilation valve, connect the first pipeline and the second pipeline, and use the pressure value of the first pipeline as the first pressure value;

[0015] Connect the first pipeline and the third pipeline, and use the pressure value of the first pipeline as the second pressure value;

[0016] Determine whether the first pressure value is greater than the second pressure value. If the first pressure value is greater than the second pressure value, then there is a leak.

[0017] Optionally, before controlling the engine to stop injecting fuel and driving the engine to idle at a preset speed via a generator, the method further includes: determining whether the vehicle status meets diagnostic conditions; if the vehicle status meets diagnostic conditions, then controlling the engine to stop injecting fuel and driving the engine to idle at a preset speed via a generator.

[0018] Optionally, determining whether the vehicle status meets the diagnostic conditions includes: if the vehicle operating mode is engine-driven mode or hybrid mode, then the vehicle status meets the diagnostic conditions; if the vehicle operating mode is electric drive mode, then the vehicle status does not meet the diagnostic conditions.

[0019] Optionally, if the vehicle operating mode is engine-driven mode or hybrid mode, then the vehicle status meets the diagnostic conditions, including:

[0020] If the vehicle is in engine-driven mode or hybrid mode, then determine whether the vehicle status meets the preset conditions. If the vehicle status meets at least one preset condition, then the vehicle status meets the diagnostic conditions.

[0021] The preset conditions include:

[0022] The liquid level in the tank is within the preset range;

[0023] The temperature difference between the engine's cooling medium and the ambient temperature is within a preset temperature difference range.

[0024] The vehicle speed is lower than the preset speed;

[0025] The vehicle battery has the preset charge level.

[0026] Optionally, after determining whether the first pressure value is greater than the second pressure value, and if the first pressure value is greater than the second pressure value, indicating a leak, the method further includes: if a leak exists, issuing an alarm signal.

[0027] This application also provides a leak diagnosis device for a fuel evaporation system, based on the fuel evaporation system leak diagnosis system described above, the fuel evaporation system leak diagnosis device comprising:

[0028] The control module is used to control the engine to stop injecting fuel and drive the engine to idle at a preset speed via a generator;

[0029] The adjustment module is used to adjust the opening of the carbon canister solenoid valve and the throttle valve so that the vacuum level of the intake manifold reaches the preset vacuum level.

[0030] The first execution module is used to close the ventilation valve, connect the first pipeline and the second pipeline, and use the pressure value of the first pipeline as the first pressure value;

[0031] The second execution module is used to connect the first pipeline and the third pipeline, and to use the pressure value of the first pipeline as the second pressure value;

[0032] The judgment module is used to determine whether the first pressure value is greater than the second pressure value.

[0033] This application also provides a vehicle including a leak diagnosis system for the fuel evaporation system as described above, which implements the leak diagnosis method for the fuel evaporation system as described above.

[0034] The fuel evaporation system leak diagnosis system, method, apparatus, and vehicle provided in this application have the following technical advantages compared with the prior art:

[0035] The third pipeline forms a reference pipeline, and the reference orifice is set according to the leakage degree requirements. If the first pressure value is greater than the second pressure value, it means that there is a leak in the whole consisting of the second pipeline, carbon canister and fuel tank, and the leakage degree is greater than the leakage degree of the reference orifice. That is, the fuel evaporation system has a leakage degree of the preset orifice diameter.

[0036] Since the diagnosis only requires determining whether there is a predetermined level of leakage in the fuel evaporation system, it is not necessary to specifically measure the leakage parameters of the fuel evaporation system. The leakage diagnosis system and method provided in this application diagnose the leakage of the fuel evaporation system. By setting a third pipeline and a reference orifice as a reference, and by switching the connection status of the first pipeline with the second pipeline and the third pipeline, and comparing the pressure values ​​when the pressure in the first pipeline is stable under the two connection states, it is possible to determine whether there is a leakage of the predetermined orifice size in the second pipeline, carbon canister, and fuel tank of the fuel evaporation system. Only by comparing the pressure values ​​under the two connection states is it possible to determine whether there is a leakage of the predetermined orifice size. There is no need for further calculations and analysis based on the detected pressure values, which simplifies the calculation process. In the early stage, it is not necessary to obtain the relationship between pressure and leakage orifice size through a large number of experiments, analyses, and calculations, which can greatly save development time, improve development efficiency, and reduce costs.

[0037] Since the environmental conditions are the same when the first and second pressure values ​​are measured, there is no need to consider the influence of external environmental conditions such as ambient temperature on the reference value during diagnosis. The diagnostic result can be obtained by comparing the magnitudes of the two data points, making it highly adaptable to diagnostic conditions. Furthermore, using the leakage diagnosis system and method provided in this application, only a third pipeline with a reference hole corresponding to the leakage degree requirement is needed for different leakage requirements, making it widely applicable.

[0038] In this application, the operating logic of the vehicle range extender is adjusted so that during the leak diagnosis process, the generator drives the engine to rotate, so that the intake manifold reaches a stable vacuum level when the engine is idling, which is used for diagnosis. There is no need to set up pumps or other components for vacuuming or air injection, which simplifies the overall structure of the leak diagnosis system, reduces costs, and also reduces the requirements for installation space, making it highly applicable. Attached Figure Description

[0039] Figure 1 This is a structural block diagram of a fuel evaporation system leak diagnosis system provided in an embodiment of this application;

[0040] Figure 2 This is a flowchart of a method for diagnosing leaks in a fuel evaporation system provided in an embodiment of this application;

[0041] Figure 3 This is a detailed flowchart of a method for diagnosing leaks in a fuel evaporation system provided in an embodiment of this application;

[0042] Figure 4 This is a structural block diagram of a leak diagnosis device for a fuel evaporation system provided in an embodiment of this application.

[0043] Appendix Figures 1-4 The reference numerals in the attached figures are explained as follows:

[0044] 1. Fuel tank; 2. First pipeline; 3. Second pipeline; 4. Third pipeline, 41. Reference port; 5. Three-way valve, 51. First port, 52. Second port, 53. Third port; 6. Controller; 7. Engine; 8. Carbon canister, 81. Vent valve; 9. Carbon canister solenoid valve; 10. Pressure detection unit; 11. Intake manifold; 12. Throttle valve; 13. First filter; 14. Second filter;

[0045] 100 Control module; 200 Adjustment module; 300 First execution module; 400 Second execution module; 500 Judgment module. Detailed Implementation

[0046] To enable those skilled in the art to better understand the technical solutions of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] This application provides a leak diagnosis system for a fuel evaporation system (hereinafter referred to as a leak diagnosis system), such as... Figure 1 As shown, the leak diagnosis system includes a fuel tank 1, a first pipeline 2, a second pipeline 3, a third pipeline 4, a controller 6, an engine 7, a generator, a carbon canister 8, a carbon canister solenoid valve 9, and a throttle valve 12. The fuel tank 1 is used to store fuel. One end of the first pipeline 2 is connected to the intake manifold 11 of the engine 7, and the other end of the first pipeline 2 is used to connect to the second pipeline 3 or the third pipeline 4. The first pipeline 2 is equipped with the aforementioned carbon canister solenoid valve 9 and a pressure detection unit 10. The pressure detection unit 10 is used to detect the pressure in the first pipeline 2. The carbon canister solenoid valve 9 is located between the intake manifold 11 and the pressure detection unit 10.

[0048] The carbon canister 8 is connected to the second pipeline 3. One end of the second pipeline 3 is connected to the oil tank 1, and the other end of the second pipeline 3 can be connected to the first pipeline 2. The carbon canister 8 is provided with an oil inlet, a vent, and an oil outlet. The oil inlet and the oil outlet are connected to the second pipeline 3. The oil inlet is connected to the oil tank 1, and the oil outlet can be connected to the first pipeline 2. The vent is provided with a ventilation valve 81. The ventilation valve 81 is connected to the controller 6 by a signal and can be opened and closed according to the control command of the controller 6.

[0049] The third pipeline 4 is provided with a reference hole 41 with a preset diameter of 0.5mm-1mm, that is, the diameter of the preset hole is 0.5mm-1mm, such as 0.5mm, 1mm, etc., which can be set according to the leakage degree requirements.

[0050] The controller 6 is connected to the engine 7, generator, carbon canister solenoid valve 9, throttle valve 12, pressure detection unit 10, and ventilation valve 81, respectively. The controller 6 can control the generator to drive the engine 7 to rotate, control the output torque of the engine 7 and whether to inject fuel, thereby ensuring that the engine 7 can stably idle at a preset speed under the drive of the generator. The controller 6 can also adjust the pressure in the intake manifold 11 of the engine 7 by adjusting the opening of the carbon canister solenoid valve 9 and the throttle valve 12, so that the intake manifold 11 can reach a stable preset vacuum. The engine 7 can also control the opening and closing of the ventilation valve 81 and obtain the pressure detection results from the pressure detection unit 10.

[0051] When the leak diagnosis system is used to diagnose the leak in the fuel evaporation system, the vehicle is in the start-up state but not in motion. The controller 6 is working and can control the generator to drive the engine 7 to rotate at a preset speed. At the same time, it controls the engine 7 to stop injecting fuel. At this time, the engine 7 is idling at the preset speed. Then, the controller 6 adjusts the opening of the carbon canister solenoid valve 9 and the opening of the throttle valve 12 to make the pressure in the intake manifold 11 of the engine 7 reach a stable preset pressure value (i.e., reach a certain vacuum). At this time, the carbon canister solenoid valve 9 is not in the fully open state.

[0052] Next, the controller 6 controls the ventilation valve 81 to close and connects the first pipeline 2 to the second pipeline 3. At this time, the oil tank 1, carbon canister 8, second pipeline 3 and first pipeline 2 are connected, and the first pipeline 2 and third pipeline 4 are disconnected. The controller 6 monitors the pressure value of the first pipeline 2 in real time according to the pressure detection unit 10. When the pressure detection unit 10 detects that the pressure in the first pipeline 2 is stable, it records the pressure value at this time as the first pressure value.

[0053] In this article, the pressure value refers to the pressure in the first pipeline 2 when it is stable. Specifically, within a preset time range, the pressure value detected by the pressure detection unit 10 fluctuates within a preset range, which indicates that the pressure in the first pipeline is stable. The specific preset time range and preset fluctuation range can be set according to the actual situation, and no specific restrictions are imposed here.

[0054] The controller 6 controls the connection between the first pipeline 2 and the third pipeline 4. At this time, the first pipeline 2 and the second pipeline 3 are disconnected. When the pressure detection unit 10 detects that the pressure in the first pipeline 2 is stable, it records the pressure value at this time as the second pressure value.

[0055] The controller 6 determines whether there is a leak by comparing the first pressure value and the second pressure value. Specifically, if the first pressure value is greater than the second pressure value, it means that the air intake of the second pipe 3 is greater than the air intake of the third pipe 4, that is, there is a leak in the fuel evaporation system and the degree of leakage reaches the preset orifice diameter. If the first pressure value is less than the second pressure value, it means that the air intake of the second pipe 3 is less than the air intake of the third pipe 4, that is, there is no leak in the fuel evaporation system that reaches the preset orifice diameter.

[0056] Of course, it is possible to connect the first pipe 2 to the second pipe 3 first, and then connect the first pipe 2 to the third pipe 4, that is, to detect the first pressure value first and then the second pressure value, or to detect the second pressure value first and then the first pressure value. In other words, the order of detecting the first pressure value and the second pressure value is not required.

[0057] In other words, the third pipeline 4 forms a reference pipeline, and the reference hole 41 is set according to the leakage degree requirements. If the first pressure value is greater than the second pressure value, it means that there is a leak in the whole consisting of the second pipeline 3, the carbon canister 8 and the fuel tank 1, and the leakage degree is greater than the leakage degree of the reference hole 41. That is, the fuel evaporation system has a leakage degree of the preset orifice diameter.

[0058] Since the diagnosis only requires determining whether there is a predetermined level of leakage in the fuel evaporation system, it is not necessary to specifically measure the leakage parameters of the fuel evaporation system. The leakage diagnosis system provided in this embodiment diagnoses the leakage situation of the fuel evaporation system. By setting the third pipe 4 and the reference hole 41 as references, and switching the connection between the first pipe 2 and the second pipe 3 and the third pipe 4, the pressure values ​​when the pressure in the first pipe 2 is stable under the two connection states are compared to determine whether there is a leakage of the predetermined hole diameter in the second pipe 3, carbon canister 8 and fuel tank 1 of the fuel evaporation system. Only the pressure values ​​under the two connection states need to be compared to determine whether there is a leakage of the predetermined hole diameter. There is no need to perform further calculations and analyses based on the detected pressure values, which simplifies the calculation process. In the early stage, it is not necessary to obtain the relationship between pressure and leakage hole diameter through a large number of experiments, analyses and calculations, which can greatly save development time, improve development efficiency and reduce costs.

[0059] Since the environmental conditions are the same when the first and second pressure values ​​are detected, there is no need to consider the influence of external environmental conditions such as ambient temperature on the reference value during diagnosis. The diagnostic result can be obtained by comparing the magnitudes of the two data points, making it highly adaptable to diagnostic conditions. Furthermore, the leak diagnosis system provided in this embodiment only requires a third pipe 4 with a reference hole corresponding to the required leakage level to meet different leakage level requirements, making it widely applicable.

[0060] In addition, in this embodiment, by adjusting the operating logic of the vehicle range extender, during the leak diagnosis process, the generator drives the engine 7 to rotate, so that the intake manifold 11 of the engine 7 reaches a stable vacuum level when the engine 7 is idling, for diagnostic use. There is no need to set up pumps or other components for vacuuming or air injection, which simplifies the overall structure of the leak diagnosis system, reduces costs, and also reduces the requirements for installation space, making it highly applicable.

[0061] Furthermore, a one-way valve is installed in the pipeline between the carbon canister solenoid valve 9 and the intake manifold 11. The flow direction of the one-way valve is from the carbon canister solenoid valve 9 to the intake manifold 11 to restrict the airflow direction and prevent gas backflow.

[0062] Furthermore, when the engine 7 is a turbocharged engine 7, a venturi tube is connected before and after the turbocharger of the engine 7. The carbon canister solenoid valve 9 is connected to the intake manifold 11, and is also connected to the venturi tube through another pipeline. A one-way valve is also installed in this pipeline. The flow direction of the one-way valve is from the carbon canister solenoid valve 9 to the venturi tube.

[0063] In this embodiment, the connection between the first pipeline 2 and the second pipeline 3, as well as between the first pipeline 2 and the third pipeline 4, can be controlled by corresponding valve components, which are signal-connected to the controller 6.

[0064] Specifically, such as Figure 1 As shown, the leak diagnosis system also includes a three-way valve 5, which has a first port 51, a second port 52 and a third port 53. The first port 51 is connected to the first pipeline 2, the second port 52 is connected to the second pipeline 3, and the third port 53 is connected to each other. The controller 6 can control the connection between the first port 51 and the second port 52 and the third port 53, thereby controlling the connection status in the leak diagnosis system.

[0065] Of course, in this embodiment, a first valve can be provided between the first pipeline 2 and the second pipeline 3, and a second valve can be provided between the first pipeline 2 and the third pipeline 4. The first valve and the second valve are two independent valves. The controller 6 controls the connection status of the leak diagnosis system by controlling the opening and closing of the first valve and the second valve. Compared with the setting of two valves, the setting of a three-way valve 5 simplifies the overall structure, simplifies the disassembly and assembly process, and ensures that the overall structure is more regular. At the same time, it also simplifies the control of the controller 6.

[0066] like Figure 1As shown, a first filter device 13 is also provided at the reference hole 41. When the first pipe 2 and the third pipe 4 are connected, due to the certain vacuum in the third pipe 4, external air can enter the third pipe 4 through the reference hole 41 and then enter the first pipe 2. Therefore, by setting the first filter device 13, dust can be prevented from entering and cleanliness can be ensured.

[0067] Similarly, such as Figure 1 As shown, a second filter device 14 is also provided at the ventilation valve 81 to filter the air entering the carbon canister 8 through the ventilation port.

[0068] This application also provides a leak diagnosis method for a fuel evaporation system based on the above-mentioned leak diagnosis system (hereinafter referred to as the leak diagnosis method), such as Figure 2 As shown, the leak diagnosis method includes the following steps:

[0069] S1: Control engine 7 to stop injecting fuel and drive engine 7 to idle at a preset speed via generator.

[0070] Engine 7 does not inject fuel. Instead, it is driven by a generator to rotate at a preset speed, i.e., engine 7 idles at the preset speed to reduce the pressure in the intake manifold 11 and create a certain degree of vacuum within the intake manifold 11. The preset speed is not limited; engine 7 can rotate at a stable speed.

[0071] S2: Adjust the opening of the carbon canister solenoid valve 9 and the throttle valve 12 to make the vacuum level of the intake manifold 11 reach the preset vacuum level.

[0072] By adjusting the carbon canister solenoid valve 9 and the throttle valve 12, the vacuum level in the intake manifold 11 is adjusted to achieve and stabilize a preset vacuum level. Specifically, the magnitude of this preset vacuum level is not limited; it can be 20 kPa to 50 kPa, specifically 20 kPa, 30 kPa, 40 kPa, or 50 kPa, depending on the actual situation. Maintaining a stable preset vacuum level in the intake manifold 11 means that the carbon canister solenoid valve 9 is neither fully open nor fully closed. In the first pipeline 2, the vacuum level on the side of the carbon canister solenoid valve 9 facing the intake manifold 11 is stable at the preset vacuum level.

[0073] S3: Close the ventilation valve 81, connect the first pipe 2 and the second pipe 3, and use the pressure value of the first pipe 2 as the first pressure value.

[0074] The oil tank 1, carbon canister 8, second pipeline 3 and first pipeline 2 are in a connected state. At this time, the first pipeline 2 and the third pipeline 4 are in a disconnected state. The pressure value of the first pipeline 2 is monitored in real time. When the pressure in the first pipeline 2 reaches a stable state, the pressure value in the first pipeline 2 is recorded as the first pressure value.

[0075] S4: Connect the first pipe 2 and the third pipe 4, and use the pressure value of the first pipe 2 as the second pressure value.

[0076] The first pipeline 2 and the third pipeline 4 are connected, while the first pipeline 2 and the second pipeline 3 are disconnected. At this time, the pressure value of the first pipeline 2 is detected in real time, and the pressure value of the first pipeline 2 under stable pressure is recorded as the second pressure value.

[0077] The third pipeline 4 forms a reference pipeline, and the second pressure value forms a reference pressure value.

[0078] S5: Determine if the first pressure value is greater than the second pressure value. If the first pressure value is greater than the second pressure value, then there is a leak.

[0079] If the first pressure value is greater than the second pressure value, it means that the air intake of the second pipe 3 is greater than the air intake of the third pipe 4, that is, there is a leak in the fuel evaporation system and the degree of leakage reaches the preset orifice diameter. If the first pressure value is less than the second pressure value, it means that the air intake of the second pipe 3 is less than the air intake of the third pipe 4, that is, there is no leak in the fuel evaporation system that reaches the preset orifice diameter.

[0080] The order of steps S3 and S4 is not restricted. Step S3 can be performed first and then step S4, that is, the first pressure value can be detected first and then the second pressure value can be detected. Alternatively, step S4 can be performed first and then step S3, that is, the second pressure value can be detected first and then the first pressure value can be detected.

[0081] The third pipeline 4 forms a reference pipeline, and the reference hole 41 is set according to the leakage degree requirements. If the first pressure value is greater than the second pressure value, it means that there is a leak in the whole consisting of the second pipeline 3, carbon canister 8 and fuel tank 1, and the leakage degree is greater than the leakage degree of the reference hole 41. That is, the fuel evaporation system has a leakage degree of the preset orifice diameter.

[0082] Since the diagnosis only requires determining whether there is a predetermined level of leakage in the fuel evaporation system, it is not necessary to specifically measure the leakage parameters of the fuel evaporation system. The leakage diagnosis method provided in this embodiment diagnoses the leakage situation of the fuel evaporation system. By setting the third pipe 4 and the reference hole 41 as references, and switching the connection between the first pipe 2 and the second pipe 3 and the third pipe 4, the pressure values ​​when the pressure in the first pipe 2 is stable under the two connection states are compared to determine whether there is a predetermined orifice leakage in the second pipe 3, carbon canister 8 and fuel tank 1 of the fuel evaporation system. Only the pressure values ​​under the two connection states need to be compared to determine whether there is a predetermined orifice leakage. There is no need to perform further calculations and analyses based on the detected pressure values, which simplifies the calculation process. In the early stage, it is not necessary to obtain the relationship between pressure and leakage orifice diameter through a large number of experiments, analyses and calculations, which can greatly save development time, improve development efficiency and reduce costs.

[0083] Since the environmental conditions are the same when the first and second pressure values ​​are detected, there is no need to consider the influence of external environmental conditions such as ambient temperature on the reference value during diagnosis. The diagnostic result can be obtained by comparing the magnitudes of the two data points, making it highly adaptable to diagnostic conditions. Furthermore, the leak diagnosis method provided in this embodiment only requires a third pipe 4 with a reference hole corresponding to the leak degree requirement for different leakage requirements, making it widely applicable.

[0084] In addition, in this embodiment, by adjusting the operating logic of the vehicle range extender, during the leak diagnosis process, the generator drives the engine 7 to rotate, so that the intake manifold 11 of the engine 7 reaches a stable vacuum level when the engine 7 is idling, for diagnostic use. There is no need to set up pumps or other components for vacuuming or air injection, which simplifies the overall structure of the leak diagnosis system, reduces costs, and also reduces the requirements for installation space, making it highly applicable.

[0085] Furthermore, such as Figure 3 As shown, before step S1, there is also step S0: determining whether the vehicle status meets the diagnostic conditions. If the diagnostic conditions are met, then step S1 is performed.

[0086] The setting of step S0 ensures that diagnostics only begin when the vehicle status meets certain conditions, thereby reducing the frequency of diagnostics and energy consumption.

[0087] Specifically, there are no specific restrictions on whether the vehicle status in step S0 meets the diagnostic conditions. Preferably, in step S0, determining whether the vehicle status meets the diagnostic conditions includes: if the vehicle operating mode is engine-driven mode or hybrid mode, then the vehicle status meets the diagnostic conditions; if the vehicle operating mode is electric drive mode, then the vehicle does not meet the diagnostic conditions.

[0088] Leakage diagnosis can be performed if the vehicle is operating in engine-driven or hybrid mode. In other words, leakage diagnosis can only be performed in engine-driven or hybrid mode; in pure electric mode, the engine 7 is not operating, and leakage diagnosis is not performed. This limitation on diagnostic conditions simplifies the control strategy of controller 6, achieving energy-saving effects.

[0089] Furthermore, in step S0, the statement that if the vehicle operating mode is engine-driven mode or hybrid mode, then the vehicle status meets the diagnostic conditions includes: if the vehicle operating mode is engine-driven mode or hybrid mode, then determining whether the vehicle status meets preset conditions; if the vehicle status meets at least one preset condition, then the vehicle status meets the diagnostic conditions; wherein, the preset conditions include the following conditions one to four:

[0090] Condition 1: The liquid level in tank 1 is within the preset liquid level range.

[0091] By installing a liquid level detection device inside the oil tank 1, the liquid level height inside the oil tank 1 is monitored in real time. The preset liquid level range is preferably 5%-85%. When the liquid level is relatively high (e.g., 90%) or low (e.g., 3%), no diagnosis is required, thereby reducing the frequency of leak diagnosis.

[0092] Condition 2: The temperature difference between the cooling medium of engine 7 and the ambient temperature is within the preset temperature difference range.

[0093] The preset temperature difference range is preferably -7℃ to 7℃. This setting increases the probability of engine 7 being diagnosed after it has been stopped for a period of time, and reduces the probability of engine 7 being diagnosed immediately after it stops. For example, after the vehicle has been driving for a period of time, the temperature of the cooling medium of engine 7 rises. When the vehicle stops after reaching its destination, the temperature difference between the cooling medium and the ambient temperature is large, so there is no need to perform a leak diagnosis at this time. After a period of time, the vehicle restarts. At this time, the temperature difference between the cooling medium of engine 7 and the ambient temperature decreases to within the preset temperature difference range, and a leak diagnosis can be performed. By limiting the preset temperature difference, the probability of performing a leak diagnosis can be reduced. While meeting the requirements for leak diagnosis, energy consumption can also be effectively reduced.

[0094] Condition 3: The vehicle speed is less than the preset speed.

[0095] The preset speed measurement is preferably no more than 5 km / h to avoid the leakage diagnosis affecting vehicle operation.

[0096] Condition 4: The vehicle battery has sufficient charge to meet the preset charge level.

[0097] The preset battery level is preferably no less than 10%, which means that there is no need to perform leak diagnosis when the battery is low, so as to save energy and extend the battery life.

[0098] In the above conditions one through four, the numbers one through four are for descriptive purposes only, to distinguish the conditions, and do not imply any order or priority. Of course, other diagnostic conditions may also be included in determining whether a vehicle's condition meets the diagnostic criteria, and no specific restrictions are placed here.

[0099] The preset condition can be one of the above conditions one to four or at least a combination of any two.

[0100] By determining the vehicle operating mode in step S0, and further determining whether the vehicle status meets preset conditions, the diagnostic frequency can be reduced, thereby reducing energy consumption. Of course, in this embodiment, there are no limitations on how to determine whether the vehicle status meets the diagnostic conditions or how to determine whether the vehicle status meets the preset conditions in step S0. For example, it can also be at least one of the following conditions:

[0101] The ambient temperature must be between 0℃ and 35℃.

[0102] The carbon canister solenoid valve 9, ventilation valve 81, pressure detection unit 10, and throttle valve 12 are operating normally;

[0103] The vehicle's idling duration meets the preset duration.

[0104] After step S5, there is also step S6, where an alarm signal is issued if a leak is found.

[0105] In other words, if the first pressure value is greater than the second pressure value, a leak is detected in the fuel evaporation system, and the leak reaches a preset orifice size. The system then activates an alarm device to send a warning signal to the user. This alarm signal can be audible, visual, or electrical, etc., to alert the user to the fuel evaporation system leak, allowing for timely repairs and preventing further damage. For example, OBD (On-Board Diagnostics), used for emission control system monitoring, should detect a leak in the fuel evaporation system if it reaches a preset orifice size. The OBD system should then display a fault code, store it in the vehicle's computer, and illuminate the fault indicator. The driver can then identify the fault code using a standard diagnostic system.

[0106] This application embodiment also provides a fuel evaporation system leak diagnosis device, which is based on the above-mentioned fuel evaporation system leak diagnosis system and specifically includes:

[0107] Control module 100 is used to control engine 7 to stop injecting fuel and drive engine 7 to idle at a preset speed via generator;

[0108] The adjustment module 200 is used to adjust the opening of the carbon canister solenoid valve 9 and the throttle valve 12 so that the vacuum degree of the intake manifold 11 reaches the preset vacuum degree.

[0109] The first execution module 300 is used to close the ventilation valve 81, connect the first pipeline 2 and the second pipeline 3, and use the pressure value of the first pipeline 2 as the first pressure value.

[0110] The second execution module 400 is used to connect the first pipeline 2 and the third pipeline 4, and to use the pressure value of the first pipeline 2 as the second pressure value.

[0111] The judgment module 500 is used to determine whether the first pressure value is greater than the second pressure value.

[0112] This application also provides a vehicle that includes the fuel evaporation system leak diagnosis system described above, and is capable of implementing the fuel evaporation system leak diagnosis method described above.

[0113] The technical effects of the fuel evaporation system leak diagnosis device and the vehicle are similar to those of the aforementioned fuel evaporation system leak diagnosis system, and will not be repeated here to save space.

[0114] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0115] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0116] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A leak diagnosis system for a fuel evaporation system, characterized in that, It includes a fuel tank, a first pipeline, a second pipeline, a third pipeline, a controller, and an engine, a generator, a carbon canister, a carbon canister solenoid valve, and a throttle valve, all of which are connected to the controller via signals. One end of the first pipeline is connected to the intake manifold of the engine, and the other end of the first pipeline is used to connect to the second pipeline or the third pipeline. The first pipeline is provided with a carbon canister solenoid valve and a pressure detection unit. The carbon canister solenoid valve is located between the intake manifold and the pressure detection unit. The second pipeline connects the carbon canister and the oil tank, and the carbon canister is also equipped with a ventilation valve; The third pipeline is equipped with a reference hole of a preset diameter.

2. The fuel evaporation system leak diagnosis system according to claim 1, characterized in that, It also includes a three-way valve, which has a first port, a second port and a third port. The first port is connected to the second pipeline, the second port is connected to the third pipeline, and the third port is connected to the first pipeline. The third port is used to connect to either the first port or the second port.

3. The fuel evaporation system leak diagnosis system according to claim 1, characterized in that, A first filter device is also provided at the reference hole.

4. The fuel evaporation system leak diagnosis system according to claim 1, characterized in that, The preset aperture ranges from 0.5mm to 1mm.

5. A method for diagnosing leaks in a fuel evaporation system, based on the fuel evaporation system leak diagnosis system as described in any one of claims 1-4, characterized in that, The method for diagnosing leaks in the fuel evaporation system includes: The engine is controlled to stop injecting fuel, and the generator drives the engine to idle at a preset speed. Adjust the opening of the carbon canister solenoid valve and the throttle valve to bring the vacuum level of the intake manifold to the preset vacuum level. Close the ventilation valve, connect the first pipeline and the second pipeline, and use the pressure value of the first pipeline as the first pressure value; Connect the first pipeline and the third pipeline, and use the pressure value of the first pipeline as the second pressure value; Determine whether the first pressure value is greater than the second pressure value. If the first pressure value is greater than the second pressure value, then there is a leak.

6. The method for diagnosing leaks in a fuel evaporation system according to claim 5, characterized in that, Before controlling the engine to stop fuel injection and driving the engine to idle at a preset speed via the generator, the method further includes: Determine whether the vehicle status meets the diagnostic conditions. If the vehicle status meets the diagnostic conditions, control the engine to stop injecting fuel and drive the engine to idle at a preset speed via the generator.

7. The method for diagnosing leaks in a fuel evaporation system according to claim 6, characterized in that, The determination of whether the vehicle status meets the diagnostic conditions includes: If the vehicle is in engine-driven mode or hybrid mode, the vehicle status meets the diagnostic criteria; if the vehicle is in electric drive mode, the vehicle status does not meet the diagnostic criteria.

8. The method for diagnosing leaks in a fuel evaporation system according to claim 7, characterized in that, If the vehicle's operating mode is engine-driven or hybrid, then the vehicle status meets the diagnostic conditions, including: If the vehicle is in engine-driven mode or hybrid mode, determine whether the vehicle status meets the preset conditions. If the vehicle status meets at least one preset condition, the vehicle status meets the diagnostic conditions. The preset conditions include: The liquid level in the tank is within the preset range; The temperature difference between the engine's cooling medium and the ambient temperature is within a preset temperature difference range. The vehicle speed is lower than the preset speed; The vehicle battery has the preset charge level.

9. The method for diagnosing leaks in a fuel evaporation system according to any one of claims 6-8, characterized in that, After determining whether the first pressure value is greater than the second pressure value, and if the first pressure value is greater than the second pressure value, indicating a leak, the method further includes: if a leak exists, issuing an alarm signal.

10. A leak diagnosis device for a fuel evaporation system, based on the fuel evaporation system leak diagnosis system according to any one of claims 1-4, characterized in that, The leak diagnosis device for the fuel evaporation system includes: The control module is used to control the engine to stop injecting fuel and drive the engine to idle at a preset speed via a generator; The adjustment module is used to adjust the opening of the carbon canister solenoid valve and the throttle valve so that the vacuum level of the intake manifold reaches the preset vacuum level. The first execution module is used to close the ventilation valve, connect the first pipeline and the second pipeline, and use the pressure value of the first pipeline as the first pressure value; The second execution module is used to connect the first pipeline and the third pipeline, and to use the pressure value of the first pipeline as the second pressure value; The judgment module is used to determine whether the first pressure value is greater than the second pressure value.

11. A vehicle, characterized in that, The system includes a leak diagnosis system for a fuel evaporation system as described in any one of claims 1-4, and implements a leak diagnosis method for a fuel evaporation system as described in any one of claims 5-9.

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