Evaporation system leak detection method and apparatus, device, vehicle, and storage medium

Abstract

The present application relates to the technical field of vehicle control, and discloses an evaporation system leak detection method and apparatus, a device, a vehicle, and a storage medium. The evaporation system leak detection method comprises: when an evaporation system of a vehicle satisfies a leak diagnosis condition, sending an operating-condition coordination request message to a powertrain control unit, so that the powertrain control unit controls an engine to operate according to preset target parameters; closing a canister shut-off valve, opening a canister solenoid valve, and successfully establishing the negative pressure in the evaporation system; and, during pressure maintenance, on the basis of a pressure change rate of the evaporation system over a preset time period, determining whether or not the evaporation system satisfies a preset diagnosis requirement. By operating the engine according to the preset target parameters, sufficient vacuum is ensured in an intake manifold to establish negative pressure for the evaporation system, thereby ensuring smooth execution of leak detection for the evaporation system during driving.

Description

Evaporative system leak detection method, device, equipment, vehicle and storage medium Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a leakage detection method, device, equipment, vehicle, and storage medium for an evaporative system. Background Art

[0002] Vehicles subject to evaporative emission requirements are required to perform leak testing on their fuel evaporation systems (hereinafter referred to as the evaporation system). This involves monitoring the integrity of the entire evaporation system, excluding the piping and connectors between the canister solenoid valve and the intake manifold, to prevent fuel vapor from escaping into the atmosphere. For example, a leak in the evaporation system is diagnosed when the leakage is greater than or equal to that of a small hole with a diameter of 1 mm. Fuel-powered vehicles typically use the engine vacuum pressure test to detect evaporation system leaks. This involves running the engine to create a negative pressure, then maintaining that pressure to detect leaks in the evaporation system. Specifically, when the engine is running, after closing the charcoal canister shut-off valve and opening the charcoal canister solenoid valve, the fuel tank and its pipelines will generate negative pressure due to the vacuum in the intake manifold. When the negative pressure measured by the pressure sensor in the fuel tank reaches the set value, the charcoal canister solenoid valve is closed, so that the evaporation system composed of the charcoal canister solenoid valve, the fuel tank cap and the charcoal canister shut-off valve is in a closed space. If there is a leak point in the closed space, the atmospheric pressure in the closed space will rise. When the rate of change of pressure exceeds the set value, it is determined that the leakage amount of the leak point in the evaporation system is greater than or equal to the leakage amount of a small hole with a diameter of 1 mm.

[0003] The prerequisite for leak detection in the evaporation system using the engine vacuum pressure maintenance method is that, while the engine is running, the negative pressure in the evaporation system successfully reaches the set target value after the charcoal canister shutoff valve is closed and the charcoal canister solenoid valve is opened according to the target duty cycle. Therefore, to ensure sufficient vacuum to establish negative pressure, the intake manifold pressure must be within a certain range and not excessive. Typically, evaporation system leak detection is performed on fuel vehicles in a stable operating condition, such as parked and idling.

[0004] For hybrid vehicles, the engine's start-stop control is affected by battery balance, energy consumption performance, and user experience. Therefore, the engine typically does not start while the vehicle is parked, making it difficult for hybrid vehicles to operate in a parked idle state. The current leak detection solution for the evaporative system in hybrid vehicles involves using an independent pump to build pressure after the vehicle is parked. This involves using an external independent pump to fill or extract gas from the evaporative system space, establishing positive or negative pressure to monitor for leaks. This solution requires adding an independent pump to the hybrid vehicle, increasing vehicle cost. Furthermore, this additional independent pump must be of high quality, resulting in a limited selection of products on the market and a low overall cost-performance ratio.

[0005] Summary of the Invention

[0006] In view of this, the present application provides a leakage detection method, device, equipment, vehicle and storage medium for an evaporative system to solve the problem that an independent pump needs to be added to a hybrid vehicle to perform leakage detection on the evaporative system, resulting in increased costs.

[0007] In a first aspect, an embodiment of the present application provides a leakage detection method for an evaporation system, comprising the following steps: when the evaporation system of a vehicle meets the leakage diagnosis conditions, sending a coordination operating condition request message to the powertrain control unit so that the powertrain control unit controls the engine to operate according to preset target parameters; wherein the target parameters are determined according to the vacuum degree of the intake manifold; closing the charcoal canister shut-off valve, opening the charcoal canister solenoid valve, and using the intake manifold to extract the gas in the evaporation system; determining whether the evaporation system has reached the target pressure based on a first pressure value detected by a first pressure sensor; when the evaporation system reaches the target pressure, closing the charcoal canister solenoid valve to maintain the pressure of the evaporation system; calculating the pressure change rate of the evaporation system within a preset time period, and determining whether the evaporation system meets the preset diagnostic requirements based on the pressure change rate.

[0008] The evaporative system leak detection method provided in this embodiment, when a vehicle's evaporative system meets leak diagnosis conditions, sends a coordinated operating condition request message to the powertrain control unit, causing it to control the engine to operate according to preset target parameters. This ensures sufficient vacuum in the intake manifold to establish negative pressure in the evaporative system. After the charcoal canister shutoff valve is closed and the charcoal canister solenoid valve is opened, successfully establishing negative pressure in the evaporative system. During the pressure maintenance process, the rate of change of the evaporative system's pressure within a preset time period is used to determine whether the evaporative system meets the preset diagnostic requirements. Because the powertrain control unit controls the engine to operate according to preset target parameters, sufficient vacuum in the intake manifold is ensured to establish negative pressure in the evaporative system. This ensures smooth evaporative system leak detection using the engine vacuum and pressure maintenance method, resolving the cost increase associated with hybrid vehicles requiring a separate pump to build pressure after parking.

[0009] In an optional embodiment, determining whether the evaporation system has reached the target pressure based on the first pressure value detected by the first pressure sensor includes: obtaining a current first pressure value detected by the first pressure sensor; judging whether the current first pressure value has reached a preset first target value, and when the current first pressure value has reached the first target value, judging that the evaporation system has reached the target pressure; when the current first pressure value has not reached the first target value, obtaining a first time period from the start time of extracting gas from the evaporation system using the intake manifold to the current time period; judging whether the first time period has reached a preset first time period threshold; when the first time period has not reached the first time period threshold, obtaining a next first pressure value detected by the first pressure sensor, using the next first pressure value as the current first pressure value, and returning to the step of judging whether the current first pressure value has reached the preset first target value; when the first time period reaches the first time period threshold, judging that there is a gross leak in the evaporation system.

[0010] That is, when the evaporation system is being evacuated, if the duration of the evaporation system evacuation reaches a preset first duration threshold, and the negative pressure in the evaporation system still fails to meet the pressure maintenance monitoring requirement, a gross leak in the evaporation system can be determined. It should be noted that the gross leak determination in this embodiment of the present application excludes the possibility of insufficient intake manifold vacuum, and is therefore more accurate.

[0011] In an optional embodiment, before sending a coordinated operating condition request message to the powertrain control unit, it also includes: judging whether the evaporation system meets basic diagnostic conditions based on basic diagnostic parameters; when the evaporation system meets the basic diagnostic conditions, judging whether the evaporation system is stable based on the stability parameters of the evaporation system; when the evaporation system is stable, determining that the evaporation system meets leakage diagnosis conditions.

[0012] This not only enables leak detection to meet diagnostic requirements, but also allows leak detection of the evaporation system to be performed when the evaporation system is stable, thereby improving the accuracy of the detection results.

[0013] In an optional embodiment, the basic diagnostic parameters include the actual ambient temperature of the vehicle's location, the actual ambient pressure of the vehicle's location, the actual water temperature of the engine, and the actual engine shutdown time; judging whether the evaporation system meets the basic diagnostic conditions based on the basic diagnostic parameters includes: when the actual ambient temperature is greater than a preset first temperature threshold, the actual ambient pressure is greater than a preset pressure threshold, the actual water temperature of the engine is greater than a preset second temperature threshold, and the actual engine shutdown time is greater than a preset second time threshold, it is determined that the evaporation system meets the basic diagnostic conditions.

[0014] This can accurately determine whether the evaporation system meets the basic diagnostic conditions.

[0015] In an optional embodiment, the stability parameters include the actual desorption flow rate of the charcoal canister, the actual running time of the engine and the actual vehicle speed; judging whether the evaporation system is stable based on the stability parameters of the evaporation system includes: when the actual desorption flow rate of the charcoal canister is greater than a preset flow threshold, the actual running time of the engine is greater than a preset third time threshold, and the actual vehicle speed is greater than a preset speed threshold, the evaporation system is determined to be stable.

[0016] This can accurately determine whether the evaporation system is stable.

[0017] In an optional implementation, the speed threshold is greater than or equal to 0.

[0018] Therefore, the leakage detection method of the evaporation system can be applied not only to driving conditions but also to idling conditions.

[0019] In an optional embodiment, when the evaporation system includes a fuel tank isolation valve, when the evaporation system meets the basic diagnostic conditions, before judging whether the evaporation system is stable according to the stability parameters of the evaporation system, it also includes: closing the fuel tank isolation valve, obtaining a second pressure value detected by a second pressure sensor in the fuel tank; judging whether the second pressure value is greater than a second target value; when the second pressure value is greater than the second target value, controlling the fuel tank isolation valve to remain in a closed state, and executing the step of judging whether the evaporation system is stable according to the stability parameters of the evaporation system.

[0020] The fuel tank isolation valve can be used to divide the evaporation system into two spaces. First, a leak test is performed on Space 1 (i.e., the portion between the fuel tank and the fuel tank isolation valve). When the second pressure value in the fuel tank is greater than a second target value, the fuel tank is deemed leak-free. Then, a leak test is performed on Space 2 (i.e., the remainder of the evaporation system excluding Space 1). Since leak testing Space 2 involves fewer steps and is faster, detection efficiency can be improved. In an optional embodiment, the evaporation system leak diagnosis method further includes: when the second pressure value is less than or equal to the second target value, opening the fuel tank isolation valve and determining whether the evaporation system is stable based on a stability parameter of the evaporation system.

[0021] That is, when the second pressure value in the fuel tank is less than or equal to the second target value, there may be a leak in the fuel tank or it may be caused by some special operating conditions. It is impossible to determine whether there is a leak in space 1. In order to detect whether there is a leak in the evaporation system, it is necessary to perform a leak test on the entire evaporation system consisting of space 1 and space 2. After opening the fuel tank isolation valve, space 1 and space 2 become a whole.

[0022] In an optional embodiment, after determining that the evaporation system meets the leakage diagnosis conditions and before sending a coordinated operating condition request message to the powertrain control unit, the step further includes: obtaining the actual acceleration of the vehicle; determining whether the actual acceleration is less than a preset acceleration threshold; when the actual acceleration is less than the acceleration threshold, executing the step of sending a coordinated operating condition request message to the powertrain control unit.

[0023] This is because, during the operation of a hybrid vehicle, the sloshing of the oil in the fuel tank can affect the negative pressure within the enclosed space of the evaporative system, reducing the accuracy of leak detection and even causing false alarms. In this embodiment of the present application, the actual vehicle acceleration is obtained before establishing a negative pressure in the evaporative system. Negative pressure is only established in the evaporative system when the actual vehicle acceleration is less than an acceleration threshold. This minimizes the impact of oil sloshing in the fuel tank on the negative pressure within the enclosed space of the evaporative system during leak detection, thereby improving leak detection accuracy.

[0024] In an optional embodiment, calculating the pressure change rate of the evaporation system within a preset time period, and determining whether the evaporation system meets the preset diagnostic requirements based on the pressure change rate includes: obtaining multiple third pressure values ​​of the evaporation system within the preset time period, and the detection time corresponding to each third pressure value; calculating the pressure change rate of the evaporation system within the preset time period based on the multiple third pressure values ​​and the detection time corresponding to each third pressure value; when the pressure change rate is less than a preset standard value, determining that the evaporation system meets the diagnostic requirements.

[0025] This makes it easy and accurate to determine whether the evaporation system meets the diagnostic requirements.

[0026] In an optional embodiment, the leakage diagnosis method of the evaporation system further includes: when the pressure change rate is greater than or equal to a standard value, determining that the evaporation system does not meet the diagnosis requirements, and issuing a prompt message indicating that there is a fault in the evaporation system.

[0027] Therefore, when the evaporation system does not meet the diagnosis requirements, a prompt message indicating that there is a fault in the evaporation system can be issued, so that the fault can be handled in a timely manner.

[0028] In a second aspect, an embodiment of the present application further provides a leakage detection device for an evaporation system, the device comprising a working condition coordination module, a vacuum pumping module, a target state determination module, a pressure maintaining module and a diagnostic module; the working condition coordination module is used to send a coordinated working condition request message to the powertrain control unit when the vehicle's evaporation system meets the leakage diagnosis conditions, so that the powertrain control unit controls the engine to operate according to preset target parameters; wherein the target parameters are determined according to the vacuum degree of the intake manifold; the vacuum pumping module is used to close the charcoal canister shut-off valve, open the charcoal canister solenoid valve, and use the intake manifold to extract the gas in the evaporation system; the target state determination module is used to determine whether the evaporation system has reached the target pressure according to the first pressure value detected by the first pressure sensor; the pressure maintaining module is used to close the charcoal canister solenoid valve when the evaporation system reaches the target pressure to maintain the pressure of the evaporation system; the diagnostic module is used to calculate the pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets the preset diagnostic requirements according to the pressure change rate.

[0029] The evaporative system leak detection method provided in this embodiment, when a vehicle's evaporative system meets leak diagnosis conditions, sends a coordinated operating condition request message to the powertrain control unit, causing it to control the engine to operate according to preset target parameters. This ensures sufficient vacuum in the intake manifold to establish negative pressure in the evaporative system. After the charcoal canister shutoff valve is closed and the charcoal canister solenoid valve is opened, successfully establishing negative pressure in the evaporative system. During the pressure maintenance process, the rate of change of the evaporative system's pressure within a preset time period is used to determine whether the evaporative system meets the preset diagnostic requirements. Because the powertrain control unit controls the engine to operate according to preset target parameters, sufficient vacuum in the intake manifold is ensured to establish negative pressure in the evaporative system. This ensures smooth evaporative system leak detection using the engine vacuum and pressure maintenance method, resolving the cost increase associated with hybrid vehicles requiring a separate pump to build pressure after parking.

[0030] In an optional embodiment, the target state determination module is used to: obtain a current first pressure value detected by the first pressure sensor; determine whether the current first pressure value reaches a preset first target value, and when the current first pressure value reaches the first target value, determine that the evaporation system reaches the target pressure; when the current first pressure value does not reach the first target value, obtain a first time period from the start time of extracting gas from the evaporation system using the intake manifold to the current time period; determine whether the first time period reaches a preset first time period threshold; when the first time period does not reach the first time period threshold, obtain a next first pressure value detected by the first pressure sensor, use the next first pressure value as the current first pressure value, and return to the step of determining whether the current first pressure value reaches the preset first target value; when the first time period reaches the first time period threshold, determine that there is a gross leak in the evaporation system.

[0031] That is to say, when the evaporation system is evacuated, if the duration of evaporation reaches a preset first duration threshold, and the negative pressure of the evaporation system still cannot meet the pressure maintenance monitoring requirement, it can be determined that there is a gross leak in the evaporation system. It should be noted that the determination of gross leaks in the embodiment of the present application excludes the situation of insufficient vacuum in the intake manifold, and is therefore more accurate. In an optional embodiment, the leakage detection device for the evaporation system further includes a leakage diagnosis condition judgment module, which includes a basic diagnosis condition judgment unit and an evaporation system stability judgment unit; the basic diagnosis condition judgment unit is used to judge whether the evaporation system meets the basic diagnosis conditions based on the basic diagnosis parameters; the evaporation system stability judgment unit is used to judge whether the evaporation system is stable based on the stability parameters of the evaporation system when the evaporation system meets the basic diagnosis conditions; when the evaporation system is stable, it is determined that the evaporation system meets the leakage diagnosis conditions.

[0032] This not only enables leak detection to meet diagnostic requirements, but also allows leak detection of the evaporation system to be performed when the evaporation system is stable, thereby improving the accuracy of the detection results.

[0033] In an optional embodiment, the basic diagnostic parameters include the actual ambient temperature of the vehicle's location, the actual ambient pressure of the vehicle's location, the actual water temperature of the engine, and the actual engine shutdown time; the basic diagnostic condition judgment unit is used to: when the actual ambient temperature is greater than a preset first temperature threshold, the actual ambient pressure is greater than a preset pressure threshold, the actual water temperature of the engine is greater than a preset second temperature threshold, and the actual engine shutdown time is greater than a preset second time threshold, determine that the evaporation system meets the basic diagnostic conditions.

[0034] This can accurately determine whether the evaporation system meets the basic diagnostic conditions.

[0035] In an optional embodiment, the stability parameters include the actual desorption flow rate of the charcoal canister, the actual running time of the engine and the actual vehicle speed; the evaporation system stability judgment unit is used to: when the actual desorption flow rate of the charcoal canister is greater than a preset flow threshold, the actual running time of the engine is greater than a preset third time threshold, and the actual vehicle speed is greater than a preset speed threshold, determine that the evaporation system is stable.

[0036] This can accurately determine whether the evaporation system is stable.

[0037] In an optional implementation, the speed threshold is greater than or equal to 0.

[0038] Therefore, the leakage detection method of the evaporation system can be applied not only to driving conditions but also to idling conditions.

[0039] In an optional embodiment, the leakage detection device of the evaporation system further includes a space division module; when the evaporation system includes a fuel tank isolation valve, when the evaporation system meets the basic diagnostic conditions, before judging whether the evaporation system is stable according to the stability parameters of the evaporation system, the space division module is used to: close the fuel tank isolation valve, obtain a second pressure value detected by a second pressure sensor in the fuel tank; judge whether the second pressure value is greater than a second target value; when the second pressure value is greater than the second target value, control the fuel tank isolation valve to continue to be in a closed state, and issue an instruction to judge whether the evaporation system is stable according to the stability parameters of the evaporation system.

[0040] The fuel tank isolation valve can be used to divide the evaporation system into two spaces. First, a leak test is performed on space 1 (i.e., the portion between the fuel tank and the fuel tank isolation valve). When the second pressure value in the fuel tank is greater than the second target value, it is considered that there is no leakage in the fuel tank. At this time, a leak test is then performed on space 2 (i.e., the rest of the evaporation system except space 1). Since leak testing is performed on space 2, the test process is shorter and the test speed is faster, thereby improving the test efficiency.

[0041] In an optional embodiment, the space division module is further configured to: when the second pressure value is less than or equal to the second target value, open the fuel tank isolation valve, and issue an instruction to determine whether the evaporation system is stable based on the stability parameter of the evaporation system.

[0042] That is, when the second pressure value in the fuel tank is less than or equal to the second target value, there may be a leak in the fuel tank or it may be caused by some special operating conditions. It is impossible to determine whether there is a leak in space 1. In order to detect whether there is a leak in the evaporation system, it is necessary to perform a leak test on the entire evaporation system consisting of space 1 and space 2. After opening the fuel tank isolation valve, space 1 and space 2 become a whole.

[0043] In an optional embodiment, the leakage detection device of the evaporative system further includes an acceleration determination module; after determining that the evaporative system meets the leakage diagnosis conditions and before sending a coordinated operating condition request message to the powertrain control unit, the acceleration determination module is configured to: obtain the actual acceleration of the vehicle; determine whether the actual acceleration is less than a preset acceleration threshold; and, when the actual acceleration is less than the acceleration threshold, issue an instruction to send a coordinated operating condition request message to the powertrain control unit.

[0044] This is because, during the operation of a hybrid vehicle, the sloshing of the oil in the fuel tank can affect the negative pressure within the enclosed space of the evaporation system, reducing the accuracy of leak detection and even causing false alarms. In this embodiment of the present application, before establishing a negative pressure in the evaporation system, the actual acceleration of the vehicle is obtained. Negative pressure is only established in the evaporation system when the actual acceleration is less than an acceleration threshold. This minimizes the impact of oil sloshing in the fuel tank on the negative pressure within the enclosed space of the evaporation system during leak detection, thereby improving leak detection accuracy.

[0045] In an optional embodiment, the diagnostic module is used to: obtain multiple third pressure values ​​of the evaporation system within a preset time period, and the detection time corresponding to each third pressure value; calculate the pressure change rate of the evaporation system within the preset time period based on the multiple third pressure values ​​and the detection time corresponding to each third pressure value; when the pressure change rate is less than a preset standard value, determine that the evaporation system meets the diagnostic requirements.

[0046] This makes it easy and accurate to determine whether the evaporation system meets the diagnostic requirements.

[0047] In an optional embodiment, the diagnosis module is further configured to: when the pressure change rate is greater than or equal to a standard value, determine that the evaporation system does not meet the diagnosis requirements, and issue a prompt message indicating that there is a fault in the evaporation system.

[0048] Therefore, when the evaporation system does not meet the diagnosis requirements, a prompt message indicating that there is a fault in the evaporation system can be issued, so that the fault can be handled in a timely manner.

[0049] In a third aspect, the present application provides a computer device comprising a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to thereby execute the leakage detection method for an evaporation system according to the first aspect or any corresponding embodiment thereof.

[0050] In a fourth aspect, an embodiment of the present application further provides a vehicle comprising the computer device of the third aspect.

[0051] In a fifth aspect, the present application provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the leakage detection method for an evaporation system according to the first aspect or any corresponding embodiment thereof.

[0052] The beneficial effects of this application are as follows:

[0053] The evaporative system leak detection method provided in this embodiment, when a vehicle's evaporative system meets leak diagnosis conditions, sends a coordinated operating condition request message to the powertrain control unit, causing it to control the engine to operate according to preset target parameters. This ensures sufficient vacuum in the intake manifold to establish negative pressure in the evaporative system. After the charcoal canister shutoff valve is closed and the charcoal canister solenoid valve is opened, successfully establishing negative pressure in the evaporative system. During the pressure maintenance process, the rate of change of the evaporative system's pressure within a preset time period is used to determine whether the evaporative system meets the preset diagnostic requirements. Because the powertrain control unit controls the engine to operate according to preset target parameters, sufficient vacuum in the intake manifold is ensured to establish negative pressure in the evaporative system. This ensures smooth evaporative system leak detection using the engine vacuum and pressure maintenance method, resolving the cost increase associated with hybrid vehicles requiring a separate pump to build pressure after parking. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0055] FIG1 is a flow chart of a method for detecting leakage in an evaporation system according to an embodiment of the present application;

[0056] FIG2 is a schematic structural diagram of an evaporation system for a hybrid vehicle according to an embodiment of the present application;

[0057] FIG3 is a flow chart of another evaporation system leakage detection method according to an embodiment of the present application;

[0058] 4 is a flow chart illustrating an example of determining whether an evaporation system meets basic diagnostic conditions based on basic diagnostic parameters according to an embodiment of the present application;

[0059] 5 is a flow chart of an example of determining whether an evaporation system is stable based on stability parameters according to an embodiment of the present application;

[0060] FIG6 is another structural schematic diagram of the evaporation system of a hybrid vehicle according to an embodiment of the present application;

[0061] FIG7 is a flow chart of another evaporation system leakage detection method according to an embodiment of the present application;

[0062] FIG8 is a schematic diagram of another evaporation system leakage detection method according to an embodiment of the present application;

[0063] FIG9 is a flow chart of a method for detecting leakage in the evaporation system of space 2 according to an embodiment of the present application;

[0064] FIG10 is a flow chart of a method for detecting leakage in the evaporation systems of space 1 and space 2 according to an embodiment of the present application;

[0065] FIG11 is a structural block diagram of an evaporation system leakage detection device according to an embodiment of the present application;

[0066] FIG12 is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0067] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0068] According to an embodiment of the present application, an embodiment of a leak detection method for an evaporative system is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0069] In this embodiment, a method for detecting leakage of an evaporative system is provided, which can be used in a computer device, wherein the computer device can be an engine control unit in a hybrid vehicle.

[0070] FIG1 is a flow chart of a method for detecting leakage in an evaporation system according to an embodiment of the present application. As shown in FIG1 , the flow chart includes the following steps:

[0071] Step S101: When the vehicle's evaporative system meets leak diagnosis conditions, a coordinated operating condition request message is sent to the powertrain control unit, causing the powertrain control unit to control the engine to operate according to preset target parameters. The target parameters are determined based on the intake manifold vacuum level. The target parameters include target speed and / or target torque.

[0072] In hybrid vehicles, the powertrain control unit (PU) controls the engine to run at preset target speeds and torques. Because intake manifold vacuum is related to engine operating parameters, the PU ensures sufficient intake manifold vacuum to create negative pressure in the evaporation system.

[0073] Specifically, the target speed and target torque of the engine can be obtained in advance through experiments, that is, the speed and torque of the engine when there is sufficient vacuum in the intake manifold can be obtained through experiments.

[0074] Step S102: Close the carbon canister shut-off valve, open the carbon canister solenoid valve, and use the intake manifold to extract gas from the evaporative system.

[0075] Specifically, negative pressure can be established for the evaporative system through the intake manifold.

[0076] Step S103: determining whether the evaporation system reaches the target pressure according to the first pressure value detected by the first pressure sensor.

[0077] Step S104: When the evaporation system reaches the target pressure, the canister solenoid valve is closed to maintain the pressure of the evaporation system.

[0078] That is to say, after the negative pressure of the evaporation system is successfully established, the pressure of the evaporation system is maintained.

[0079] Step S105: Calculate the pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets the preset diagnostic requirements based on the pressure change rate.

[0080] The evaporative system leak detection method provided in this embodiment, when the vehicle's evaporative system meets the leakage diagnosis conditions, sends a coordinated operating condition request message to the powertrain control unit, so that the powertrain control unit controls the engine to operate according to preset target parameters, thereby ensuring that there is sufficient vacuum in the intake manifold to establish negative pressure for the evaporative system; after the charcoal canister shut-off valve is closed and the charcoal canister solenoid valve is opened, and the negative pressure of the evaporative system is successfully established, during the pressure maintenance process, it is determined whether the evaporative system meets the preset diagnostic requirements based on the pressure change rate of the evaporative system within a preset time period.

[0081] In this embodiment, during the driving process of the hybrid vehicle, the powertrain control unit controls the engine to operate according to preset target parameters, which can ensure that there is sufficient vacuum in the intake manifold to establish negative pressure for the evaporation system, thereby ensuring that leak detection of the evaporation system using the engine vacuum pressure maintenance method can be carried out smoothly, solving the problem of increased costs due to the need to use an independent pump to build pressure after the hybrid vehicle is parked.

[0082] In this embodiment, a method for detecting leakage in an evaporation system is provided, which can be used in an engine control unit in a hybrid vehicle. FIG2 is a schematic structural diagram of an evaporation system for a hybrid vehicle according to an embodiment of the present application. In FIG2 , the dashed lines represent wiring harnesses, and the solid lines represent pipelines. As shown in FIG2 , the components of the evaporation system for a hybrid vehicle include: an engine, an engine control unit, a powertrain control unit, a chassis control unit, a fuel tank, a fuel tank isolation valve, a fuel tank pressure sensor 1, a fuel tank pressure sensor 2, a charcoal canister, a charcoal canister solenoid valve, a charcoal canister shut-off valve, an ash filter, a tee, a throttle body, a supercharger, an air filter, and related pipelines. The components that fall within the scope of evaporation system leakage detection include: a fuel tank, a fuel tank isolation valve, a charcoal canister, a fuel tank pressure sensor 1, a fuel tank pressure sensor 2, a charcoal canister solenoid valve, a charcoal canister shut-off valve, and the pipelines connecting them.

[0083] FIG3 is a flow chart of another evaporation system leakage detection method according to an embodiment of the present application. As shown in FIG3 , the flow chart includes the following steps:

[0084] Step S301: judging whether the evaporation system meets the basic diagnostic conditions according to the basic diagnostic parameters. If the evaporation system meets the basic diagnostic conditions, the process proceeds to step S302; otherwise, the evaporation system leakage detection is exited.

[0085] In an optional embodiment, the basic diagnostic parameters include the actual ambient temperature of the vehicle, the actual ambient pressure of the vehicle, the actual water temperature of the engine and / or the actual shutdown time of the engine.

[0086] Specifically, basic diagnostic parameters include: the actual ambient temperature at the vehicle's location, the actual ambient pressure at the vehicle's location, the actual engine water temperature, and the actual engine shutdown duration. The actual engine water temperature may be the water temperature at the initial engine startup; the actual engine shutdown duration may be the length of time the vehicle's drive system was inactive before the engine was started.

[0087] Specifically, determining whether the evaporation system meets basic diagnostic conditions based on the basic diagnostic parameters includes determining that the evaporation system meets the basic diagnostic conditions when the actual ambient temperature is greater than a preset first temperature threshold, the actual ambient pressure is greater than a preset pressure threshold, the actual engine water temperature is greater than a preset second temperature threshold, and the actual engine shutdown duration is greater than a preset second duration threshold. Specifically, determining whether the evaporation system meets the basic diagnostic conditions based on the basic diagnostic parameters can be performed when the hybrid vehicle is started.

[0088] In an optional embodiment, when there are multiple basic diagnostic parameters, determining whether the evaporation system meets the basic diagnostic conditions based on the basic diagnostic parameters includes: obtaining a basic diagnostic parameter and determining whether the obtained basic diagnostic parameter is greater than a corresponding target value; when there is a basic diagnostic parameter that is less than or equal to the corresponding target value, determining that the evaporation system does not meet the basic diagnostic conditions, and stopping obtaining the next basic diagnostic parameter; when all basic diagnostic parameters are greater than the corresponding target values, determining that the evaporation system meets the basic diagnostic conditions.

[0089] For example, as shown in FIG4 , when the basic diagnostic parameters include: the actual ambient temperature at the vehicle's location, the actual ambient pressure at the vehicle's location, the actual engine water temperature, and the actual engine shutdown duration, determining whether the evaporation system meets the basic diagnostic conditions based on the basic diagnostic parameters includes:

[0090] Step Sa1: Determine whether the actual ambient temperature is higher than the first temperature threshold. If yes, proceed to step Sa2. Otherwise, determine that the basic diagnostic condition is not met.

[0091] Step Sa2: Determine whether the actual engine water temperature is higher than the second temperature threshold. If yes, proceed to step Sa3. Otherwise, determine that the basic diagnostic condition is not met.

[0092] Step Sa3: Determine whether the actual ambient pressure is higher than the pressure threshold. If yes, proceed to step Sa4. Otherwise, determine that the basic diagnostic condition is not met.

[0093] Step Sa4: Determine whether the actual engine shutdown duration is higher than a second duration threshold. If so, determine that the basic diagnostic condition is met; otherwise, determine that the basic diagnostic condition is not met.

[0094] Step S302: judging whether the evaporation system is stable according to the stability parameters of the evaporation system; when the evaporation system is stable, proceeding to step S303; otherwise, exiting the evaporation system leakage detection.

[0095] In an optional embodiment, the stability parameters include the actual canister desorption flow rate, the actual engine operating time, and / or the actual vehicle speed. Specifically, the stability parameters include the actual canister desorption flow rate, the actual engine operating time, and the actual vehicle speed. The actual canister desorption flow rate may be the actual cumulative canister desorption flow rate, and the actual engine operating time may be the actual cumulative engine operating time.

[0096] Specifically, judging whether the evaporation system is stable based on the stability parameters of the evaporation system includes: when the actual desorption flow of the carbon canister is greater than a preset flow threshold, the actual engine running time is greater than a preset third time threshold, and the actual vehicle speed is greater than a preset speed threshold, the evaporation system is determined to be stable.

[0097] The speed threshold is greater than or equal to 0. Therefore, the evaporation system leakage detection method can be applied not only to driving conditions but also to idling conditions.

[0098] It should be noted that the embodiments of the present application are generally applied to driving conditions. This is because, compared with leak detection during parking and idling, leak detection during driving has the following advantages: parking and idling require suppressing engine shutdown, and engine shutdown will conflict with the normal start-stop strategy of hybrid vehicles, affecting fuel consumption; and when leak detection of the evaporation system is performed at parking and idling, the charcoal canister shut-off valve and the charcoal canister solenoid valve will be activated, and the NVH (Noise, Vibration, Harshness) is easily perceived by the user; however, when leak detection of the evaporation system is performed during driving, the user is basically unaware of it.

[0099] In an optional embodiment, when there are multiple stability parameters, determining whether the evaporation system is stable based on the stability parameters of the evaporation system includes: obtaining a stability parameter and determining whether the obtained stability parameter is greater than a corresponding target value; when there is a stability parameter that is less than or equal to the corresponding target value, determining that the evaporation system is unstable and stopping obtaining the next stability parameter; when all stability parameters are greater than the corresponding target values, determining that the evaporation system is stable.

[0100] For example, as shown in FIG5 , when the stability parameters include the actual cumulative desorption flow rate of the carbon canister, the actual cumulative engine operating time, and the actual vehicle speed, determining whether the evaporation system is stable based on the stability parameters of the evaporation system includes:

[0101] Step Sb1: Determine whether the actual cumulative desorption flow rate of the carbon canister exceeds the flow rate threshold. If it exceeds, proceed to step Sb2; otherwise, determine that the evaporation system is unstable.

[0102] Step Sb1: determining whether the actual accumulated engine operating time exceeds a third time threshold; if so, proceeding to step Sb2; otherwise, determining that the evaporation system is unstable;

[0103] Step Sc1: Determine whether the actual vehicle speed exceeds a speed threshold. If so, determine that the evaporation system is unstable. Otherwise, determine that the evaporation system is unstable.

[0104] Step S303: Acquire the actual acceleration of the vehicle.

[0105] Step S304: Determine whether the actual acceleration is less than a preset acceleration threshold; when the actual acceleration is less than the acceleration threshold, proceed to step S305; otherwise, exit the evaporation system leakage detection.

[0106] This is because, during the operation of a hybrid vehicle, the sloshing of the oil in the fuel tank can affect the negative pressure within the enclosed space of the evaporative system, reducing the accuracy of leak detection and even causing false alarms. In this embodiment of the present application, the actual vehicle acceleration is obtained before establishing a negative pressure in the evaporative system. Negative pressure is only established in the evaporative system when the actual vehicle acceleration is less than an acceleration threshold. This minimizes the impact of oil sloshing in the fuel tank on the negative pressure within the enclosed space of the evaporative system during leak detection, thereby improving leak detection accuracy.

[0107] Specifically, the actual acceleration may be positive acceleration or negative acceleration.

[0108] Step S305: Sending a coordinated operating condition request message to the powertrain control unit so that the powertrain control unit controls the engine to operate according to preset target parameters.

[0109] Step S306: Close the carbon canister shut-off valve, open the carbon canister solenoid valve, and use the intake manifold to extract gas from the evaporative system.

[0110] Step S307: Acquire the current first pressure value detected by the first pressure sensor.

[0111] Specifically, as shown in FIG2 , the current first pressure value detected by the fuel tank pressure sensor 1 is acquired.

[0112] Step S308: Determine whether the current first pressure value reaches the preset first target value. When the current first pressure value reaches the first target value, proceed to step S311; otherwise, proceed to step S309.

[0113] Step S309: obtaining a first duration from the start of vacuuming the evaporation system to the current duration.

[0114] Step S310: Determine whether the first time length reaches a preset first time length threshold. When the first time length does not reach the preset first time length threshold, obtain the next first pressure value detected by the first pressure sensor, use the next first pressure value as the current first pressure value, and go to step S307; otherwise, there is a gross leak in the evaporation system.

[0115] That is, when the evaporation system is being evacuated, if the duration of the evaporation system evacuation reaches a preset first duration threshold, and the negative pressure in the evaporation system still fails to meet the pressure maintenance monitoring requirement, a gross leak in the evaporation system can be determined. It should be noted that the present application's gross leak determination excludes situations where insufficient intake manifold vacuum exists, and therefore is more accurate.

[0116] Step S311: Close the canister solenoid valve to maintain the pressure of the evaporation system.

[0117] Step S312: Calculate the pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets the preset diagnostic requirements based on the pressure change rate.

[0118] In an optional embodiment, calculating the pressure change rate of the evaporation system within a preset time period, and determining whether the evaporation system meets the preset diagnostic requirements according to the pressure change rate includes:

[0119] A plurality of third pressure values ​​of the evaporation system within a preset time period and a detection time corresponding to each third pressure value are obtained; a pressure change rate of the evaporation system within the preset time period is calculated based on the plurality of third pressure values ​​and the detection time corresponding to each third pressure value; when the pressure change rate is less than a preset standard value, it is determined that the evaporation system meets the diagnostic requirements; when the pressure change rate is greater than or equal to the standard value, it is determined that the evaporation system does not meet the diagnostic requirements, and a prompt message indicating that there is a fault in the evaporation system is issued.

[0120] The evaporation system of this embodiment does not include a fuel tank isolation valve. The evaporation system leakage detection method provided by this embodiment, during the driving process of the hybrid vehicle, controls the engine to operate according to preset parameters through the powertrain control unit, which can ensure that there is sufficient vacuum in the intake manifold to establish a negative pressure for the evaporation system, thereby ensuring that the evaporation system leak detection using the engine vacuum pressure maintenance method can be carried out smoothly; and before the negative pressure is established in the evaporation system, the actual acceleration of the vehicle is obtained. Only when the actual acceleration of the vehicle is less than the acceleration threshold is the negative pressure established in the evaporation system. As a result, during the leak detection, the shaking of the oil in the fuel tank has little effect on the negative pressure in the enclosed space of the evaporation system, thereby improving the accuracy of the leak detection.

[0121] This embodiment provides a method for detecting leaks in an evaporative system that can be used in an engine control unit in a hybrid vehicle. Figure 6 is a schematic diagram of the structure of an evaporative system for a hybrid vehicle according to an embodiment of the present application. Figure 6 differs from Figure 2 in that Figure 6 also includes a fuel tank isolation valve. Due to the presence of the fuel tank isolation valve, the evaporative system leakage detection range is isolated into two spaces: Space 1 and Space 2. Space 1 is the space enclosed by the fuel tank, fuel tank pressure sensor 2, fuel tank isolation valve, and its piping; Space 2 is the space enclosed by the fuel tank isolation valve, canister solenoid valve, canister, fuel tank pressure sensor 1, canister shut-off valve, and its piping.

[0122] FIG7 is a flow chart of another evaporation system leakage detection method according to an embodiment of the present application, and FIG8 is a schematic diagram of another evaporation system leakage detection method according to an embodiment of the present application. As shown in FIG7 and FIG8 , the process includes the following steps:

[0123] Step S701: Determine whether the evaporation system meets basic diagnostic criteria based on basic diagnostic parameters. If the evaporation system meets the basic diagnostic criteria, the process proceeds to step S702; otherwise, the evaporation system leak detection process is terminated. For details, please refer to step S301 in the embodiment shown in FIG3 , and will not be repeated here.

[0124] Step S702: Close the fuel tank isolation valve and obtain a second pressure value in the fuel tank.

[0125] That is to say, when the evaporation system meets the basic diagnostic conditions, close the oil tank isolation valve and divide the evaporation system into two parts, space 1 and space 2.

[0126] Specifically, the second pressure value in the fuel tank can be obtained through the fuel tank pressure sensor 2 in the fuel tank.

[0127] Step S703: Determine whether the second pressure value is greater than the second target value; when the second pressure value is greater than the second target value, control the oil tank isolation valve to continue to be in the closed state, and proceed to step S704; when the second pressure value is less than or equal to the second target value, open the oil tank isolation valve and proceed to S713.

[0128] This is because, after the fuel tank isolation valve is closed, the fuel tank is a closed space, and therefore it is possible to determine whether there is leakage in the fuel tank based on the second pressure value in the fuel tank.

[0129] When the second pressure value in the fuel tank is greater than the second target value, there is no leakage in the fuel tank, thereby completing the detection of whether there is leakage in space 1 of the evaporation system; next, it is necessary to detect whether there is leakage in space 2, that is, turn to step S704, and detect whether there is leakage in space 2 through steps S704 to S712.

[0130] When the second pressure value in the fuel tank is less than or equal to the second target value, there may be leakage in the fuel tank or it may be caused by some special working conditions. It is impossible to determine whether there is leakage in space 1. In order to detect whether there is leakage in the evaporation system, it is necessary to go to step S713 and detect whether there is leakage in the evaporation system through steps S713 to S723.

[0131] Step S704: Determine whether the evaporation system is stable based on the stability parameters of the evaporation system. If the evaporation system is stable, proceed to step S705; otherwise, exit the evaporation system leakage detection. For details, please refer to step S302 of the embodiment shown in FIG3 , which will not be repeated here.

[0132] Step S705: Sending a coordinated operating condition request message to the powertrain control unit so that the powertrain control unit controls the engine to operate according to preset target parameters.

[0133] Step S706: Close the carbon canister shut-off valve, open the carbon canister solenoid valve, and use the intake manifold to extract gas from the evaporative system.

[0134] Since the fuel tank isolation valve has been controlled to be in a closed state in step S703 before entering step S704, as shown in Figure 6, after closing the carbon canister stop valve and opening the carbon canister solenoid valve in step S706, vacuuming the evaporation system is vacuuming space 2.

[0135] Step S707: Obtain the current first pressure value detected by the first pressure sensor. As shown in Figure 6, the first pressure value detected by the first pressure sensor is the pressure value in space 2. Specifically, the current first pressure value in the fuel tank can be obtained by the fuel tank pressure sensor 1 in the fuel tank.

[0136] Step S708: Determine whether the current first pressure value reaches the preset first target value. When the current first pressure value reaches the first target value, proceed to step S711; otherwise, proceed to step S709.

[0137] That is to say, when the first pressure detection value reaches the preset first target value, the vacuum degree of the space 2 has reached the requirement of pressure maintenance monitoring.

[0138] Step S709: Obtaining a first duration from the start of vacuuming the evaporation system to the current duration.

[0139] Step S710: Determine whether the first time length reaches a preset first time length threshold. When the first time length does not reach the preset first time length threshold, obtain the next first pressure value detected by the first pressure sensor, use the next first pressure value as the current first pressure value, and proceed to step S707; otherwise, there is a gross leak in the evaporation system.

[0140] That is, when evacuating space 2, if the vacuum level in space 2 still fails to meet the pressure-maintaining monitoring requirement after the evacuation time reaches the preset first time threshold, a gross leak in the evaporation system can be determined. It should be noted that this application's gross leak determination excludes insufficient intake manifold vacuum, making it more accurate.

[0141] Step S711: Close the canister solenoid valve to maintain the pressure of the evaporation system.

[0142] Step S712: Calculate the pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets the preset diagnostic requirements based on the pressure change rate. Please refer to step S312 of the embodiment shown in Figure 3 for details, which will not be repeated here.

[0143] To illustrate the leakage detection method for space 2 more clearly, a specific example is given. Figure 9 is a flow chart of the leakage detection method for space 2 according to an embodiment of the present application. As shown in Figure 9, first, the stability of the evaporation system is determined based on the actual cumulative desorption flow of the carbon canister, the actual cumulative running time of the engine, and the actual vehicle speed. When the evaporation system is stable, the engine control unit will send a diagnostic instruction to the powertrain control unit to request coordinated working conditions. At the same time, the engine control unit controls the fuel tank isolation valve to close, the carbon canister shut-off valve to close, and the carbon canister solenoid valve to open according to the set target duty cycle. When the negative pressure measured by the fuel tank pressure sensor 2 in space 2 reaches the set target value, the carbon canister solenoid valve is closed. If the negative pressure decays within a certain period of time and does not exceed the set target value, it is determined that there is no 1mm leakage in the evaporation system in space 2, that is, there is no 1mm leakage in the entire evaporation system space (space 1 + space 2).

[0144] Step S713: Determine whether the evaporation system is stable based on the stability parameters of the evaporation system. If the evaporation system is stable, proceed to step S714; otherwise, exit the evaporation system leakage detection. For details, please refer to step S302 of the embodiment shown in FIG3 , which will not be repeated here.

[0145] Step S714: Acquire the actual acceleration of the vehicle.

[0146] Step S715: Determine whether the actual acceleration is less than a preset acceleration threshold; when the actual acceleration is less than the acceleration threshold, proceed to step S716; otherwise, exit the evaporation system leakage detection.

[0147] Step S716: Sending a coordinated operating condition request message to the powertrain control unit so that the powertrain control unit controls the engine to operate according to preset parameters.

[0148] Step S717: Close the carbon canister shut-off valve, open the carbon canister solenoid valve, and evacuate the evaporation system.

[0149] Since the fuel tank isolation valve has been opened in step S703 before entering step S713, as shown in Figure 6, after closing the carbon canister stop valve and opening the carbon canister solenoid valve in step S717, vacuuming the evaporation system means vacuuming space 1 and space 2.

[0150] Step S718: Acquire the current first pressure value detected by the first pressure sensor.

[0151] As shown in Figure 6, the first pressure detection value detected by the first pressure sensor is the pressure value in space 1 and space 2. Specifically, the current first pressure value in the fuel tank can be obtained by tank pressure sensor 1 in the fuel tank, and the current first pressure value in the fuel tank can also be obtained by tank pressure sensor 2 in the fuel tank.

[0152] Step S719: Determine whether the current first pressure value reaches the preset first target value. When the current first pressure value reaches the first target value, proceed to step S722; otherwise, proceed to step S720.

[0153] That is to say, when the first pressure detection value reaches the preset first target value, the vacuum degrees of space 1 and space 2 have reached the pressure maintenance monitoring requirement.

[0154] Step S720: Obtain a first duration from the start of vacuuming the evaporation system to the current duration.

[0155] Step S721: Determine whether the first time length reaches the preset first time length threshold. When the first time length does not reach the preset first time length threshold, obtain the next first pressure value detected by the first pressure sensor, use the next first pressure value as the current first pressure value, and go to step S718; otherwise, there is a gross leak in the evaporation system.

[0156] That is, when evacuating Spaces 1 and 2, if the vacuum level in Spaces 1 and 2 still fails to meet the pressure-maintaining monitoring requirement after the evacuation time reaches a preset first time threshold, a gross leak in the evaporation system can be determined. It should be noted that this application's gross leak determination excludes insufficient intake manifold vacuum, making it more accurate.

[0157] Step S722: Close the canister solenoid valve to maintain the pressure of the evaporation system.

[0158] Step S723: Calculate the pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets the preset diagnostic requirements based on the pressure change rate.

[0159] To illustrate the leakage detection method for space 1 and space 2 more clearly, a specific example is provided. FIG10 is a flow chart of the evaporation system leakage detection method for space 1 and space 2 according to an embodiment of the present application. As shown in FIG10 , first, the stability of the evaporation system is determined based on the actual cumulative desorption flow of the carbon canister, the actual cumulative engine operating time, and the actual vehicle speed. When the evaporation system is stable, the actual vehicle acceleration is determined to be less than a preset acceleration threshold. When the actual acceleration is less than the acceleration threshold, the engine control unit sends a coordinated operating condition request message to the powertrain control unit. At the same time, the engine control unit controls the fuel tank isolation valve to close, the carbon canister shut-off valve to close, and the carbon canister solenoid valve to open according to the set target duty cycle. When the negative pressure measured by the fuel tank pressure sensor 2 in space 2 reaches the set target value, the carbon canister solenoid valve is closed. If the negative pressure decays within a certain period of time and does not exceed the set target value, it is determined that there is no 1mm leakage in the evaporation system in space 2, that is, there is no 1mm leakage in the entire evaporation system space (space 1 + space 2).

[0160] Figures 9 and 10 show that they are largely identical. The difference between the two is that, in Figure 10, after the evaporation system stabilizes, before sending a coordinated operating condition request message to the powertrain control unit, it is necessary to determine whether the vehicle's actual acceleration is less than a preset acceleration threshold. This is because when leak detection is performed only on Space 2, since Space 2 does not include the fuel tank, any sloshing of the oil in the tank will not affect the negative pressure in Space 2 and thus the accuracy of leak detection. Therefore, in Figure 9, it is not necessary to determine whether the vehicle's actual acceleration is less than the preset acceleration threshold. When leak detection is performed on Spaces 1 and 2, Spaces 1 and 2 include the fuel tank. In this case, to prevent sloshing of the oil in the tank from affecting the negative pressure in Spaces 1 and 2, the vehicle's actual acceleration must be controlled to be less than the acceleration threshold.

[0161] As can be seen, this application provides a hybrid vehicle evaporative system leak diagnosis method. This method splits the evaporative system space into two compartments, innovates on the engine vacuum and pressure maintenance method, fully incorporates the operating characteristics of the hybrid vehicle engine, and adopts a unique control strategy. Through the coordinated operation of the powertrain control unit and the engine control unit, the system commands the engine to operate at a set speed and torque during diagnosis, addressing the problem of insufficient vacuum during driving. At the same time, the chassis control unit introduces acceleration signal control to ensure stable operating conditions during driving diagnosis, address the impact of oil level fluctuations on pressure during driving, and minimize false alarm faults. This invention eliminates the hybrid vehicle evaporative leak diagnosis's reliance on idle-start engine conditions. Unlike idle-start engine vacuum solutions and the positive-pressure pump or negative-pressure pump shutdown diagnosis solutions commonly used in hybrid vehicles in the industry, it provides a robust and cost-effective evaporative leak diagnosis device and a diagnostic control method for preventing false alarm faults during driving.

[0162] This embodiment also provides a leak detection device for an evaporation system, which is used to implement the aforementioned embodiments and alternative implementations. Details already described will not be repeated. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. While the devices described in the following embodiments are preferably implemented using software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0163] This embodiment provides a leakage detection device for an evaporation system, as shown in FIG11 , comprising:

[0164] The operating condition coordination module 1101 is configured to send an operating condition coordination request message to the powertrain control unit when the vehicle's evaporative system meets the leak diagnosis conditions, so that the powertrain control unit controls the engine to operate according to preset target parameters; wherein the target parameters are determined based on the vacuum degree of the intake manifold;

[0165] The vacuum module 1102 is used to close the carbon canister shut-off valve, open the carbon canister solenoid valve, and use the intake manifold to extract the gas in the evaporative system;

[0166] a target state determination module 1103, configured to determine whether the evaporation system has reached a target pressure according to a first pressure value detected by the first pressure sensor;

[0167] The pressure maintaining module 1104 is used to close the canister solenoid valve when the evaporation system reaches the target pressure to maintain the pressure of the evaporation system;

[0168] The diagnosis module 1105 is configured to calculate the pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets a preset diagnosis requirement based on the pressure change rate.

[0169] In an optional embodiment, the target state determination module is used to: obtain a current first pressure value detected by the first pressure sensor; determine whether the current first pressure value reaches a preset first target value, and when the current first pressure value reaches the first target value, determine that the evaporation system reaches the target pressure; when the current first pressure value does not reach the first target value, obtain a first time period from the start time of extracting gas from the evaporation system using the intake manifold to the current time period; determine whether the first time period reaches a preset first time period threshold; when the first time period does not reach the first time period threshold, obtain a next first pressure value detected by the first pressure sensor, use the next first pressure value as the current first pressure value, and return to the step of determining whether the current first pressure value reaches the preset first target value; when the first time period reaches the first time period threshold, determine that there is a gross leak in the evaporation system.

[0170] In an optional embodiment, the leakage detection device of the evaporation system further includes a leakage diagnosis condition judgment module, which includes a basic diagnosis condition judgment unit and an evaporation system stability judgment unit; the basic diagnosis condition judgment unit is used to judge whether the evaporation system meets the basic diagnosis conditions based on the basic diagnosis parameters; the evaporation system stability judgment unit is used to judge whether the evaporation system is stable based on the stability parameters of the evaporation system when the evaporation system meets the basic diagnosis conditions; when the evaporation system is stable, it is determined that the evaporation system meets the leakage diagnosis conditions.

[0171] In an optional embodiment, the basic diagnostic parameters include the actual ambient temperature of the vehicle's location, the actual ambient pressure of the vehicle's location, the actual water temperature of the engine, and the actual engine shutdown time; the basic diagnostic condition judgment unit is used to: when the actual ambient temperature is greater than a preset first temperature threshold, the actual ambient pressure is greater than a preset pressure threshold, the actual water temperature of the engine is greater than a preset second temperature threshold, and the actual engine shutdown time is greater than a preset second time threshold, determine that the evaporation system meets the basic diagnostic conditions.

[0172] In an optional embodiment, the stability parameters include the actual desorption flow rate of the charcoal canister, the actual running time of the engine and the actual vehicle speed; the evaporation system stability judgment unit is used to: when the actual desorption flow rate of the charcoal canister is greater than a preset flow threshold, the actual running time of the engine is greater than a preset third time threshold, and the actual vehicle speed is greater than a preset speed threshold, determine that the evaporation system is stable.

[0173] In an optional implementation, the speed threshold is greater than or equal to 0.

[0174] In an optional embodiment, the leakage detection device of the evaporation system further includes a space division module; when the evaporation system includes a fuel tank isolation valve, when the evaporation system meets the basic diagnostic conditions, before judging whether the evaporation system is stable according to the stability parameters of the evaporation system, the space division module is used to: close the fuel tank isolation valve, obtain a second pressure value detected by a second pressure sensor in the fuel tank; judge whether the second pressure value is greater than a second target value; when the second pressure value is greater than the second target value, control the fuel tank isolation valve to continue to be in a closed state, and issue an instruction to judge whether the evaporation system is stable according to the stability parameters of the evaporation system.

[0175] In an optional embodiment, the space division module is further configured to: when the second pressure value is less than or equal to the second target value, open the fuel tank isolation valve, and issue an instruction to determine whether the evaporation system is stable based on the stability parameter of the evaporation system.

[0176] In an optional embodiment, the leakage detection device of the evaporative system further includes an acceleration determination module; after determining that the evaporative system meets the leakage diagnosis conditions and before sending a coordinated operating condition request message to the powertrain control unit, the acceleration determination module is configured to: obtain the actual acceleration of the vehicle; determine whether the actual acceleration is less than a preset acceleration threshold; and, when the actual acceleration is less than the acceleration threshold, issue an instruction to send a coordinated operating condition request message to the powertrain control unit.

[0177] In an optional embodiment, the diagnostic module is used to: obtain multiple third pressure values ​​of the evaporation system within a preset time period, and the detection time corresponding to each third pressure value; calculate the pressure change rate of the evaporation system within the preset time period based on the multiple third pressure values ​​and the detection time corresponding to each third pressure value; when the pressure change rate is less than a preset standard value, determine that the evaporation system meets the diagnostic requirements.

[0178] In an optional embodiment, the diagnosis module is further configured to: when the pressure change rate is greater than or equal to a standard value, determine that the evaporation system does not meet the diagnosis requirements, and issue a prompt message indicating that there is a fault in the evaporation system.

[0179] The leakage detection device for the evaporation system in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0180] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0181] An embodiment of the present application further provides a computer device having the leakage detection device of the evaporation system shown in FIG11 .

[0182] Please refer to Figure 12, which is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present application. As shown in Figure 12, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in or on the memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 12 takes a processor 10 as an example.

[0183] The processor 10 may be a central processing unit (CPU), a network processor (NPU), or a combination thereof. The processor 10 may also include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device (PLD) may be a complex programmable logic device (CPLD), a field programmable gate array (FPGA), a general purpose array logic (GAL), or any combination thereof.

[0184] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0185] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created based on the use of a computer device for displaying a small program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0186] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0187] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means, and FIG12 takes the bus connection as an example.

[0188] The input device 30 can receive input digital or character information and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touch pad, an indicator stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display, and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0189] The embodiments of the present application also provide a computer-readable storage medium. The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; optionally, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0190] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A method for detecting leakage of an evaporation system, characterized in that: The method comprises: When the evaporative system of the vehicle meets the leakage diagnosis conditions, sending a coordinated operating condition request message to the powertrain control unit so that the powertrain control unit controls the engine to operate according to preset target parameters; wherein the target parameters are determined based on the vacuum degree of the intake manifold; closing the carbon canister shutoff valve, opening the carbon canister solenoid valve, and extracting gas from the evaporative system using the intake manifold; determining whether the evaporation system reaches a target pressure according to a first pressure value detected by a first pressure sensor; When the evaporation system reaches the target pressure, closing the canister solenoid valve to maintain the pressure of the evaporation system; A pressure change rate of the evaporation system within a preset time period is calculated, and whether the evaporation system meets a preset diagnostic requirement is determined based on the pressure change rate.

2. The method according to claim 1, characterized in that Determining whether the evaporation system reaches the target pressure according to the first pressure value detected by the first pressure sensor includes: Obtaining a current first pressure value detected by the first pressure sensor; determining whether the current first pressure value reaches a preset first target value, and determining that the evaporation system has reached the target pressure when the current first pressure value reaches the first target value; and obtaining a first time period from a start time of extracting gas from the evaporation system using the intake manifold to a current time when the current first pressure value does not reach the first target value; Determining whether the first duration reaches a preset first duration threshold; When the first duration does not reach the first duration threshold, obtaining a next first pressure value detected by the first pressure sensor, using the next first pressure value as the current first pressure value, and returning to the step of determining whether the current first pressure value reaches a preset first target value; When the first time period reaches the first time period threshold, it is determined that a gross leak exists in the evaporation system.

3. The method according to claim 1, characterized in that Before sending the coordinated operating condition request message to the powertrain control unit, it also includes: determining whether the evaporation system meets basic diagnostic conditions according to basic diagnostic parameters; When the evaporation system meets the basic diagnostic conditions, determining whether the evaporation system is stable according to the stability parameter of the evaporation system; When the evaporation system is stable, it is determined that the evaporation system satisfies the leakage diagnosis condition.

4. The method according to claim 3, characterized in that The basic diagnostic parameters include the actual ambient temperature of the vehicle, the actual ambient pressure of the vehicle, the actual engine water temperature, and the actual engine shutdown time; The determining whether the evaporation system meets the basic diagnostic conditions according to the basic diagnostic parameters includes: When the actual ambient temperature is greater than a preset first temperature threshold, the actual ambient pressure is greater than a preset pressure threshold, the actual engine water temperature is greater than a preset second temperature threshold, and the actual engine shutdown time is greater than a preset second time threshold, it is determined that the evaporation system meets the basic diagnostic conditions.

5. The method according to claim 3, characterized in that The stability parameters include the actual desorption flow rate of the carbon canister, the actual running time of the engine and the actual vehicle speed; The determining whether the evaporation system is stable according to the stability parameter of the evaporation system includes: When the actual desorption flow rate of the carbon canister is greater than a preset flow rate threshold, the actual engine operating time is greater than a preset third time threshold, and the actual vehicle speed is greater than a preset speed threshold, it is determined that the evaporation system is stable.

6. The method according to claim 5, characterized in that The speed threshold is greater than or equal to 0.

7. The method according to claim 3, characterized in that When the evaporation system includes a fuel tank isolation valve, and when the evaporation system meets the basic diagnostic conditions, before determining whether the evaporation system is stable based on the stability parameters of the evaporation system, the method further includes: closing the fuel tank isolation valve and obtaining a second pressure value detected by a second pressure sensor in the fuel tank; determining whether the second pressure value is greater than a second target value; When the second pressure value is greater than the second target value, the fuel tank isolation valve is controlled to remain in a closed state, and a step of determining whether the evaporation system is stable according to a stability parameter of the evaporation system is performed.

8. The method according to claim 7, characterized in that Also includes: When the second pressure value is less than or equal to the second target value, the fuel tank isolation valve is opened, and a step of determining whether the evaporation system is stable according to a stability parameter of the evaporation system is performed.

9. The method according to claim 3 or 7, characterized in that After determining that the evaporation system meets the leakage diagnosis condition and before sending the coordinated operating condition request message to the powertrain control unit, the method further includes: Get the actual acceleration of the vehicle; Determining whether the actual acceleration is less than a preset acceleration threshold; When the actual acceleration is less than the acceleration threshold, a step of sending a coordinated operating condition request message to a powertrain control unit is executed.

10. The method according to claim 1, characterized in that Calculating the pressure change rate of the evaporation system within a preset time period and determining whether the evaporation system meets a preset diagnostic requirement according to the pressure change rate includes: Acquiring a plurality of third pressure values of the evaporation system within a preset time period and a detection time corresponding to each third pressure value; calculating a pressure change rate of the evaporation system within the preset time period according to a plurality of third pressure values and a detection time corresponding to each third pressure value; When the pressure change rate is less than a preset standard value, it is determined that the evaporation system meets the diagnosis requirement.

11. The method according to claim 10, characterized in that Also includes: When the pressure change rate is greater than or equal to the standard value, it is determined that the evaporation system does not meet the diagnosis requirement, and a prompt message indicating that a fault exists in the evaporation system is issued.

12. A leakage detection device for an evaporation system, characterized in that: The device comprises: an operating condition coordination module, configured to, when the evaporative system of the vehicle meets a leak diagnosis condition, send a coordinated operating condition request message to a powertrain control unit, so that the powertrain control unit controls the engine to operate according to preset target parameters; wherein the target parameters are determined based on the vacuum degree of the intake manifold; a vacuum module, used for closing the carbon canister shut-off valve, opening the carbon canister solenoid valve, and extracting gas from the evaporative system using the intake manifold; a target state determination module, configured to determine whether the evaporation system has reached a target pressure according to a first pressure value detected by a first pressure sensor; a pressure maintaining module, configured to close the canister solenoid valve when the evaporation system reaches the target pressure, so as to maintain the pressure of the evaporation system; The diagnosis module is configured to calculate a pressure change rate of the evaporation system within a preset time period, and determine whether the evaporation system meets a preset diagnosis requirement based on the pressure change rate.

13. The device according to claim 12, characterized in that The target state determination module is used to: Obtaining a current first pressure value detected by the first pressure sensor; determining whether the current first pressure value reaches a preset first target value, and determining that the evaporation system has reached the target pressure when the current first pressure value reaches the first target value; and obtaining a first time period from a start time of extracting gas from the evaporation system using the intake manifold to a current time when the current first pressure value does not reach the first target value; Determining whether the first duration reaches a preset first duration threshold; When the first duration does not reach the first duration threshold, obtaining a next first pressure value detected by the first pressure sensor, using the next first pressure value as the current first pressure value, and returning to the step of determining whether the current first pressure value reaches a preset first target value; When the first time period reaches the first time period threshold, it is determined that a gross leak exists in the evaporation system.

14. The device according to claim 12, characterized in that It also includes a leakage diagnosis condition judgment module, which includes a basic diagnosis condition judgment unit and an evaporation system stability judgment unit; The basic diagnostic condition judgment unit is used to judge whether the evaporation system meets the basic diagnostic conditions according to the basic diagnostic parameters; The evaporation system stability judgment unit is configured to judge whether the evaporation system is stable according to the stability parameter of the evaporation system when the evaporation system meets the basic diagnostic condition; and determine that the evaporation system meets the leakage diagnosis condition when the evaporation system is stable.

15. The device according to claim 14, characterized in that The basic diagnostic parameters include the actual ambient temperature of the vehicle, the actual ambient pressure of the vehicle, the actual engine water temperature, and the actual engine shutdown time; The basic diagnostic condition judgment unit is used to determine that the evaporation system meets the basic diagnostic conditions when the actual ambient temperature is greater than a preset first temperature threshold, the actual ambient pressure is greater than a preset pressure threshold, the actual engine water temperature is greater than a preset second temperature threshold, and the actual engine shutdown time is greater than a preset second time threshold.

16. The device according to claim 14, characterized in that The stability parameters include the actual desorption flow rate of the carbon canister, the actual running time of the engine and the actual vehicle speed; The evaporation system stability judgment unit is used to determine that the evaporation system is stable when the actual desorption flow rate of the carbon canister is greater than a preset flow threshold, the actual engine operating time is greater than a preset third time threshold, and the actual vehicle speed is greater than a preset speed threshold.

17. The device according to claim 16, characterized in that The speed threshold is greater than or equal to 0.

18. The device according to claim 14, characterized in that The invention also includes a space division module; when the evaporation system includes a fuel tank isolation valve and when the evaporation system meets the basic diagnostic conditions, before determining whether the evaporation system is stable based on the stability parameters of the evaporation system, the space division module is configured to: closing the fuel tank isolation valve and obtaining a second pressure value detected by a second pressure sensor in the fuel tank; determining whether the second pressure value is greater than a second target value; When the second pressure value is greater than the second target value, the fuel tank isolation valve is controlled to remain in a closed state, and an instruction is issued to determine whether the evaporation system is stable according to the stability parameter of the evaporation system.

19. The device according to claim 18, characterized in that The space division module is further configured to: when the second pressure value is less than or equal to the second target value, open the fuel tank isolation valve and issue an instruction to determine whether the evaporation system is stable according to the stability parameter of the evaporation system.

20. The device according to claim 14 or 18, characterized in that The system further includes an acceleration determination module; after determining that the evaporation system meets the leakage diagnosis conditions and before sending a coordinated operating condition request message to the powertrain control unit, the acceleration determination module is configured to: Get the actual acceleration of the vehicle; Determining whether the actual acceleration is less than a preset acceleration threshold; When the actual acceleration is less than the acceleration threshold, an instruction is issued to send a coordinated operating condition request message to a powertrain control unit.

21. The device according to claim 12, characterized in that The diagnostic module is used to: Acquiring a plurality of third pressure values of the evaporation system within a preset time period and a detection time corresponding to each third pressure value; calculating a pressure change rate of the evaporation system within the preset time period according to a plurality of third pressure values and a detection time corresponding to each third pressure value; When the pressure change rate is less than a preset standard value, it is determined that the evaporation system meets the diagnosis requirement.

22. The device according to claim 21, characterized in that The diagnosis module is further configured to: when the pressure change rate is greater than or equal to the standard value, determine that the evaporation system does not meet the diagnosis requirement, and issue a prompt message indicating that a fault exists in the evaporation system.

23. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the leakage detection method for the evaporation system according to any one of claims 1 to 11 by executing the computer instructions.

24. A vehicle, characterized in that: A computer device comprising the method of claim 23.

25. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the leakage detection method for an evaporation system according to any one of claims 1 to 11.

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