Module for detecting leakage of a device

Abstract

The invention relates to a module (14) for detecting leaks in a device, the module comprising a pressure sensor (8) and a pump (2) for generating pressure, the module being intended to reliably detect and / or quantify leaks in a device with a large sealing volume using a compact device, characterized in that the module (14) has a closable reference volume (11) which can be fluidically connected to an oil tank interface (10) by means of a valve (9) and can be separated from this in a sealing-fluid manner, wherein the pressure in the reference volume (11) can be detected by means of the pressure sensor (8), wherein a pressure can be generated in the reference volume (11) by means of the pump (2) and wherein the reference volume (11) can be fluidically connected to and separated from an atmospheric outlet (1) by means of a shut-off valve (4) via a reference partition (5) with a defined flow cross section.

Description

Technical Field

[0001] This invention relates to modules according to embodiments. Background Technology

[0002] In particular, high requirements are placed on the fuel tank system in motor vehicles in terms of its sealing performance to prevent accidental leakage of fuel or fuel vapor. For this purpose, diagnostic methods known from DE197 02 584C2, DE197 55 401 C2 and DE195 27 367C2 are used to detect leaks.

[0003] In particular, methods are known in the prior art in which leaks in a tank system are determined by pressure drop. For example, an overpressure is applied to the volume to be inspected, and then the manner in which the overpressure drops is detected. From the results, it can be determined whether a leak exists, and even the size of the leak can be roughly estimated.

[0004] A known drawback of these systems and methods is that their measurements lead to relatively imprecise assumptions about the leak size. This can result in the leak size being determined to be excessive based on existing measurements, even though the actual leak size would still meet permissible limits. Consequently, misdiagnosis is possible. Summary of the Invention

[0005] Therefore, the object of the present invention is to reliably detect and / or quantify leaks in devices with large sealing volumes using a compact device.

[0006] The present invention achieves the above objectives through the features of its embodiments.

[0007] According to the present invention, it is first recognized that the module used for leak detection must be provided with a reference volume that can be sealed in a fluid-tight manner to enable self-diagnosis of the module. Therefore, it is possible to check whether the module itself introduces a leak into the device under inspection.

[0008] Furthermore, it has been recognized that by utilizing a reference volume that can be optionally connected to or separated from the tank, a compact device, i.e. a module, can be integrated into existing systems to selectively detect pressure ratios and their time progression in both small and correspondingly large volumes.

[0009] Furthermore, it has been recognized that pressure sensors can not only detect the pressure or pressure drop or pressure rise time curve in a reference volume, but also simultaneously detect the pressure ratio in a large volume oil tank connected to the oil tank interface.

[0010] It has also been recognized that pumps can be used to selectively set the pressure at different locations of valves used in the module. Taking into account a reference diaphragm, the leakage area—the area through which fluid can flow out of the device's volume—can be determined from the pressure ratio and its time curve.

[0011] Using the invention described herein, the diameter of the leak area can be determined with an accuracy of ±15%.

[0012] In the first position of the valve, the tank interface can be connected to the atmosphere and separated from the reference volume via an atmospheric outlet, and in the second position, it is connected to the reference volume and separated from the atmospheric outlet. Therefore, the tank can be connected to or separated from the reference volume using only one valve. The tank can also be vented by connecting the tank interface to the atmosphere. This valve is therefore advantageously designed as a switching valve.

[0013] The reference volume can be connected to the atmospheric outlet via a shut-off valve. A flow line extending from the reference volume to the atmospheric outlet is provided, and a reference baffle with a defined flow cross-section is installed in the flow line. When fluid flows into the atmosphere, the reference baffle achieves a throttling effect. The throttling effect can be adjusted by regulating the flow cross-section. When the shut-off valve is open, venting can be performed on the reference volume. The fuel tank can also be additionally vented by opening the shut-off valve.

[0014] An atmospheric outlet allows access to the filter, through which fluid can flow out to the atmosphere. The filter is preferably designed as a dust filter. This prevents dust from seeping into the module and / or tank from the environment.

[0015] A check valve can be placed between the reference volume and the pump to prevent backflow from the reference volume to the pump. Therefore, the pressure in the reference volume can be reliably maintained when the pump is shut off. This simplifies the module's self-diagnostics. Leaks in the reference volume, check valve, shut-off valve, pressure sensor, and / or switching valve can be identified. Another advantage of the check valve arrangement is that the pump does not need to be "sealed," meaning the pump does not need to be started under pressure.

[0016] Furthermore, check valves help the pressure to tend towards a constant value and subsequently remain constant. In this context, it's important to consider that initially a higher pressure is established, but after all parts of the system under pressure have reacted and expanded, that pressure tends towards a constant, possibly lower, value.

[0017] The module can have a base with a tank interface for flanged connection to a device with a tank, an atmospheric outlet for discharging fluid into the atmosphere, and a module control device with an interface for connecting to electronic equipment in a motor vehicle or other system to output information about leaks. This module is adaptable to any tank system and can be flanged as a standalone, compact device. The module is a self-contained structural unit, requiring no components from the vehicle itself, such as valves, measuring baffles, measuring tubes, or pressure sensors. Furthermore, the module control device integrates electronic equipment for controlling the measurement process and evaluating measurements within the module. Preferably, the module control device only provides complete information to the vehicle's electronic equipment or onboard computer.

[0018] Specifically, the module is connected to an activated carbon filter via a flange to the oil tank.

[0019] The modules described herein can also be used outside of automotive applications, such as in industries where container leaks must be identified and detected.

[0020] Devices including modules of the type described herein can also include a fuel tank for a motor vehicle, connected to a fuel tank interface via an intermediate connection of an activated carbon filter, wherein a pipeline leading from the activated carbon filter to the motor of the motor vehicle is operable to be closed or opened by a regeneration valve. Optionally, a valve for controlling fuel vapor is arranged in the pipeline from the fuel tank to the activated carbon filter. The regeneration valve is used to degas or vent the activated carbon container of the motor vehicle. This type of valve is used to meter fuel vapor from the activated carbon filter of the motor vehicle. In such a device, methods for detecting leaks in the device can be implemented.

[0021] In this context, a method for detecting leaks in a device with a tank can be performed using a module of the type described herein, wherein the measurement includes a pressure drop in at least one of a reference volume and the volume of the tank. The module is capable of self-diagnosis, thereby determining, after determining its sealing performance, the area within the device, particularly the tank, through which fluid can flow out. Within the scope of self-diagnosis, a leak measurement is performed on the reference volume to ensure that the switching valve is in the correct position after the measurement process, thereby ensuring the connection between the tank and the atmosphere.

[0022] This module can be used to execute methods, specifically the following types of diagnostic methods. These methods can include the following steps:

[0023] - When the reference volume under overpressure is connected to the atmosphere and fluid flows from the reference volume into the atmosphere through the reference partition, the first pressure drop is detected by a pressure sensor.

[0024] -Detect a second pressure drop in a reference volume connected to the fuel tank and under overpressure conditions.

[0025] -Detecting a third pressure drop, wherein a flow-guiding connection is created between the reference volume in an overpressured state, the oil tank connected to the reference volume, and the atmosphere, so that fluid from the oil tank and / or from the reference volume can flow out to the atmosphere through the reference baffle.

[0026] By measuring the pressure drop separately at each step, the method measured the pressure drop three times.

[0027] The first pressure drop is caused by fluid flowing out of the reference volume through the reference baffle; the second pressure drop is caused by fluid flowing out of both the reference volume and the tank volume through the undetermined area of ​​the leak; and the third pressure drop is caused by fluid flowing out of both the reference volume and the tank volume through both the undetermined area of ​​the leak and the reference baffle. Specifically, the size of the leak area can be determined by knowledge of the reference baffle, although this knowledge is not mandatory. The diameter of the reference baffle is preferably in the range of 0.1 mm to 0.8 mm.

[0028] The method can also include the following steps, wherein a second pressure drop measurement is performed, essentially using the method described above for leak detection:

[0029] - When the pump is shut off, the reference volume is separated from the atmosphere and the oil tank, and a flow-guiding connection is established between the oil tank and the atmosphere.

[0030] -With the connection between the fuel tank and the atmosphere separated, a flow-guiding connection is established between the reference volume and the fuel tank, wherein pressure is built up in both the reference volume and the fuel tank when the pump is turned on.

[0031] - Maintain constant pressure when the pump is turned on.

[0032] -Shut down the pump and use a pressure sensor to check for pressure drops caused by leaks in the unit or tank.

[0033] - When shutting off the pump, while establishing flow connections between the oil tank and the atmosphere, and between the reference volume and the atmosphere, disconnect the flow connections between the reference volume and the oil tank.

[0034] -By isolating the flow path between the oil tank and the atmosphere, and separating the flow path between the reference volume and the atmosphere, and establishing a flow path between the oil tank and the reference volume, pressure increases in the reference volume and the oil tank are generated through fluid evaporation when the pump is turned off.

[0035] -By establishing a flow connection between the fuel tank and the atmosphere, the flow connection between the reference volume and the fuel tank is separated, thereby achieving fuel tank venting while the pump is off, and establishing a flow connection between the reference volume and the atmosphere while the pump is off.

[0036] - Separate the flow path between the reference volume and the atmosphere, and determine the pressure sensor offset when the pump is shut off.

[0037] Therefore, simplified methods can be executed.

[0038] A highly accurate method for detecting leaks in devices with fuel tanks may include the following steps:

[0039] - When the reference volume is isolated from the tank and atmosphere with the pump shut off, a flow-guiding connection is established between the tank and the atmosphere.

[0040] - With the pump switched on, pressure is built up in a reference volume that is separated from the tank and atmosphere in a sealed fluid manner.

[0041] - With the pump shut off, check the reference volume and module sealing using a pressure sensor.

[0042] - With the pump running, a guiding connection is established between the reference volume and the atmosphere so that fluid can flow out to the atmosphere through the reference baffle.

[0043] - To keep the pressure formed by the switched-on pump relative to the reference diaphragm constant.

[0044] -Shut down the pump and check the pressure drop across the reference diaphragm using a pressure sensor.

[0045] - With the tank and reference volume separated from the atmosphere, a flow-guiding connection is established between the reference volume and the tank, preventing fluid from flowing into the atmosphere via the reference baffle. This involves building pressure in the reference volume and tank when the pump is turned on.

[0046] - Maintain constant pressure when the pump is turned on.

[0047] -Shut down the pump and use a pressure sensor to check for pressure drops caused by leaks in the unit or tank.

[0048] - Establish a flow-guiding connection between the reference volume, the tank, and the atmosphere so that fluid from the tank and / or the reference volume can flow to the atmosphere via the reference baffle when the pump is turned on, wherein the pump builds pressure.

[0049] - Maintain constant pressure when the pump is turned on.

[0050] - Shut down the pump while maintaining the flow connection between the reference volume, the tank, and the atmosphere, so that fluid from the tank and / or the reference volume can flow out to the atmosphere via the reference baffle.

[0051] -By establishing a flow connection between the fuel tank and the atmosphere, the flow connection between the reference volume and the fuel tank is separated, allowing fluid from the fuel tank to flow out into the atmosphere and enabling venting of the fuel tank when the pump is turned off.

[0052] -By isolating the flow connection between the oil tank and the atmosphere, and separating the flow connection between the reference volume and the atmosphere, and establishing a flow connection between the oil tank and the reference volume, a pressure rise is generated in the reference volume and the oil tank through fluid evaporation when the pump is turned off.

[0053] -By establishing a flow connection between the fuel tank and the atmosphere, the flow connection between the reference volume and the fuel tank is separated, thereby achieving fuel tank venting when the pump is shut off, and establishing a flow connection between the reference volume and the atmosphere when the pump is shut off.

[0054] - Separate the flow path between the reference volume and the atmosphere, and determine the pressure sensor offset when the pump is shut off.

[0055] The above steps are preferably performed sequentially. This method performs three pressure drop measurements, the evaluations of which are always achieved within the same, approximately the same, or substantially the same pressure range, thereby eliminating pressure-dependent measurement accuracy of the pressure sensor.

[0056] In the above method, the pressure is kept constant by pressure regulation during the pressure holding time, thereby enabling the module and device to reach a stable state and tend to stabilize in a pressure-stable manner.

[0057] When the pump is shut off, and the reference volume is separated from the atmosphere and the tank, the first step of establishing a flow connection between the tank and the atmosphere corresponds to the normal state of the module.

[0058] The steps of separating the guide flow between the reference volume and the atmosphere and determining the pressure sensor offset when the pump is shut down are used to re-establish the module's normal state.

[0059] This method can preferably be performed in a motor vehicle where the motor is not running. Therefore, the method can be performed with particular precision, and the area of ​​the leak can be determined with particular accuracy. The diagnostics described herein are performed only when the fuel tank cap is closed, the regeneration valve is closed, and the optional FTIV (i.e., the valve for retaining fuel vapor) is open for diagnostics of the entire system or closed for a portion of the space and isolated from the motor. However, the method can also be implemented while the motor is running.

[0060] The leakage area of ​​the device can be quantitatively determined and / or output by the module. The gas volume in the tank can be calculated to check the reasonableness of the determined leakage area.

[0061] The diameter of the leak area, particularly the region assumed to be circular, can be detected with an accuracy of + / -15%. The module described herein is suitable for detecting diameters with this accuracy. Attached Figure Description

[0062] The diagram shows:

[0063] Figure 1 A schematic diagram of the module is shown, which can be mechanically and electronically connected as a structural unit to a fuel tank system of a motor vehicle.

[0064] Figure 2 It shows that it has the following characteristics: Figure 1 The device for connecting modules,

[0065] Figure 3 It shows the method for detecting according to Figure 2 A simplified flowchart illustrating the method for addressing leakage in the device, and

[0066] Figure 4 It shows the method for detecting according to Figure 2 A flowchart illustrating a more precise method for detecting leaks in the device.

[0067] Figure 5 It shows according to Figure 4 A list of steps for a precise method for detecting leaks, showing the corresponding switching states of relevant valves and pump operating modes during each step, and the corresponding proportions of physical parameters during each step; and

[0068] Figure 6 A diagram illustrating the formula used to determine and inspect the size of a leak is shown. Detailed Implementation

[0069] Figure 1 A module 14 for detecting leaks is shown, which includes a pressure sensor 8 and a pump 2 for generating pressure.

[0070] Module 14 has a sealable reference volume 11, which can be fluidly connected to and separated from the tank interface 10 via valve 9 in a sealed fluid manner. The pressure within the reference volume 11 can be detected by pressure sensor 8. Pressure can be generated within the reference volume 11 by pump 2. The reference volume 11 can be fluidly connected to and separated from the atmosphere outlet 1 via a reference baffle 5 having a defined flow cross-section via shut-off valve 4.

[0071] The reference volume preferably has a volume between 20 ml and 100 ml. The tank interface 10 can be connected via a flange to... Figure 2 The oil tank 15 is connected to the oil tank or a pipeline from the oil tank. A pressure sensor 8 is connected to a reference volume 11, allowing the pressure within the reference volume 11 and the oil tank 15 to be detected by the pressure sensor 8. A pump 2 is connected to the reference volume 11, enabling pressure to be generated within the reference volume and the oil tank 15 by means of the pump 2. The pump 2 has a pump motor 3.

[0072] In the first position of valve 9, tank interface 10 is connected to the atmosphere via atmospheric outlet 1 and separated from reference volume 11, and in the second position, it is connected to reference volume 11 and separated from atmospheric outlet 1. Valve 9 is designed here as a switching valve.

[0073] The reference volume 11 can be connected to the atmospheric outlet 1 via a shut-off valve 4. A flow line extends from the reference volume 11 to the atmospheric outlet 1, and reference baffles 5 with diameters of 0.1 mm and 0.8 mm are installed in the flow line. The flow line leads to a line that connects the tank interface 10 to the atmospheric outlet 1. The reference baffles 5 are arranged between the shut-off valve 4 and the reference volume 11.

[0074] Figure 2 The diagram shows that atmospheric outlet 1 leads into filter 13, i.e., a dust filter, through which fluid can flow into the atmosphere.

[0075] A check valve 12 is positioned between the reference volume 11 and the pump 2 to prevent backflow from the reference volume 11 to the pump 2. Only four outlets allow fluid to exit the reference volume 11. The first outlet leads to the reference baffle 5, the second outlet leads to the check valve or the pump 2, the third outlet leads to the tank interface 10, and the fourth outlet terminates at the pressure sensor 8.

[0076] Figure 1 and Figure 2 The module 14 is shown to have a base having a tank interface 10 for flanged connection to a device having a tank 15. The tank interface 10 can be directly flanged to the tank 15 or directly connected to a pipeline extending from the tank, or the tank interface 10 can be connected via, for example... Figure 2 The intermediate connection of the activated carbon filter 16 shown is connected to the oil tank 15 by a flange.

[0077] The substrate has an atmospheric outlet 1 for discharging fluid into the atmosphere. The substrate also has a modular control device 6 with an interface 7 for connecting to electronic equipment or other systems in a motor vehicle to output information about the leak.

[0078] The module control device 6 includes measuring electronic equipment and control electronic equipment. The module control device 6 can provide information on whether there is excessive leakage. Optionally, the module control device 6 can also output the size of the leakage area as information.

[0079] Figure 2 An apparatus including module 14 and fuel tank 15 of a motor vehicle is shown. The fuel tank is connected to fuel tank interface 10 via an intermediate connection of activated carbon filter 16, wherein a line from activated carbon filter 16 leads to motor 17 of the motor vehicle, which can be closed or opened via regeneration valve 18.

[0080] Another line runs from the fuel tank 15 to the activated carbon filter 16, in which the FTIV, i.e., valve 19 for retaining fuel vapor, is located. Although Figure 2 The FTIV is shown, but it can also be omitted. The FTIV is an optional component.

[0081] In this regard, another line with FTIV runs from the oil tank 15 to the activated carbon filter 16. Two lines run from the activated carbon filter 16, one through the regeneration valve 18 to the motor 17 and the other to the module 14, which can be connected to the reference volume 11 via the valve 9.

[0082] Module 14 can be connected as an assembly unit to a device having an oil tank 15 via a flange. Preferably, there are only three interfaces: a mechanical oil tank interface 10, a mechanical interface to the atmosphere, i.e., atmospheric outlet 1, and an electronic interface indicated by interface 7.

[0083] Figure 4 and Figure 5 The method of using module 14 to detect leaks in a device having a tank 15 is illustrated schematically, and the method includes the following steps:

[0084] Step S1: When pump 2 is shut off, and the reference volume 11 is separated from the atmosphere and the oil tank 15, a flow connection is established between the oil tank 15 and the atmosphere. Step S1 represents the normal state, in which the oil tank 15 is in contact with the atmosphere.

[0085] Step S2 illustrates the pressure build-up via pump 2. When pump 2 is turned on, pressure is built up in a reference volume 11, which is fluidly sealed from tank 15 and the atmosphere. If no pressure is built up, pump 2 is faulty. If pressure is built up only slowly, it indicates that the switching valve is open or the voltage to pump 2 is too low.

[0086] The sealing performance of reference volume 11 is measured in step S3. When pump 2 is off, the sealing performance of reference volume 11, and consequently module 14, is detected using pressure sensor 8. If the pressure drop is too large, module 14 is not sealed. If the pressure drop is very large, shut-off valve 4 may be opened.

[0087] In step S4, shut-off valve 4 is opened and pressure is established relative to reference diaphragm 5. When pump 2 is turned on, a guiding connection is established between reference volume 11 and the atmosphere, allowing fluid to flow out to the atmosphere via reference diaphragm 5. If the pressure does not drop, shut-off valve 4 is closed.

[0088] Through step S5, after the pressure stabilizes, the pressure relative to the reference diaphragm 5 is kept constant, thus setting it to a constant value or a value that is as constant as possible. The pressure established by the switched-on pump 2 relative to the reference diaphragm 5 remains constant. If the pump flow rate is too low, the reference diaphragm 5 becomes severely contaminated because the pressure is adjusted to a constant value.

[0089] The self-diagnosis of module 14 is performed through steps S2 to S5, which includes checking pump 2, valve 9 (i.e., switching valve, shut-off valve 4), reference diaphragm 5, and pressure sensor. Module 14 is checked as a whole.

[0090] In step S6, pump 2 is shut down and the pressure drop across reference diaphragm 5 is checked using pressure sensor 8. Pressure value Δp0 is measured at time point t0 and pressure value Δp1 is measured at time point t1 by pressure sensor 8. This is also done in steps S9 and S12. Because a differential pressure sensor is used as pressure sensor 8, pressure values ​​are measured. The pressure drop between two time points or between two pressure values, i.e., between two pressure differential values, is measured.

[0091] In step S7, with the connection between the oil tank 15 and the reference volume 11 and the atmosphere separated, a flow-guiding connection is established between the reference volume 11 and the oil tank 15, so that the fluid can no longer flow out to the atmosphere through the reference partition 5. When the pump 2 is turned on, pressure is built in the reference volume 11 and the oil tank 15.

[0092] In step S8, the pressure remains constant while pump 2 is turned on.

[0093] In step S9, pump 2 is isolated and a pressure sensor is used to check for a pressure drop due to leakage in the device or tank 15. Pressure sensor 8 measures the pressure value Δp2 at time t2 and the pressure value Δp3 at time t3.

[0094] In step S10, a flow-guiding connection is established between the reference volume 11, the oil tank 15, and the atmosphere, so that when the pump motor 3 of the pump 2 is turned on, the fluid from the oil tank 15 and / or the reference volume 11 can flow out to the atmosphere through the reference partition 5, wherein the pump 2 builds pressure.

[0095] In step S11, the pressure remains constant when pump 2 or pump motor 3 is turned on.

[0096] In step S12, pump 2 is shut off while maintaining the flow connection between reference volume 11, oil tank 15, and atmosphere, allowing fluid from oil tank and / or reference volume 11 to flow out to atmosphere via reference baffle 5. Pressure sensor 8 measures pressure value Δp4 at time t4 and pressure value Δp5 at time t5.

[0097] Pressure drop is measured in steps S6, S9, and S12 respectively, thus measuring the pressure drop three times using this method.

[0098] The first pressure drop occurs because fluid flows out of the reference volume 11 through the reference partition 5; the second pressure drop occurs because fluid flows out of the reference volume 11 and the tank 15 through the leaking area to be determined; and the third pressure drop occurs because fluid flows out of the reference volume 11 and the tank 15 through the leaking area to be determined and through the reference partition 5.

[0099] In step S13, when a flow-guiding connection is established between the oil tank 15 and the atmosphere, the flow-guiding connection between the reference volume 11 and the oil tank 15 is separated, so that the fluid from the oil tank 15 can flow out to the atmosphere and the oil tank 15 is vented when the pump 2 is turned off.

[0100] By separating the flow path between the oil tank 15 and the atmosphere in step S14, separating the flow path between the reference volume 11 and the atmosphere, and establishing the flow path between the oil tank 15 and the reference volume 11, the pressure in the reference volume 11 and the oil tank 15 increases due to fluid evaporation when the pump 2 is turned off. Therefore, step S14 describes the pressure increase due to evaporation.

[0101] Step S15 describes separating the flow connection between the reference volume 11 and the oil tank 15 while establishing the flow connection between the oil tank 15 and the atmosphere, so that the oil tank 15 is vented when the pump 2 is turned off, and the flow connection between the reference volume 11 and the atmosphere is established when the pump 2 is turned off. Therefore, step S15 describes venting.

[0102] In step S16, when pump 2 is turned off, the connection between the reference volume 11 and the atmosphere is separated and the offset of the pressure sensor is determined.

[0103] The method described herein is performed in a motor vehicle when motor 17 is not operating; the motor is an internal combustion motor.

[0104] The leakage area of ​​the device is quantitatively determined and output by module 14, i.e., transmitted to the electronic equipment of the motor vehicle via interface 7. The following methods can be used for quantitative determination: Figure 6 The formula shown in the figure:

[0105] Area of ​​leakage:

[0106]

[0107] A TL -Total tank leakage area, α-Flow coefficient, p atm -Atmospheric pressure, R S - Specific gas constant, T - Temperature of the fluid or gas, in Kelvin (K), V Ref - Internal volume or reference volume 11 of module 14.

[0108] The flow coefficient is a parameter that takes into account all losses that occur when fluid flows through the baffle.

[0109] The values ​​of Δp and t, i.e., the pressure values ​​measured within the range of pressure drop at a given time point, and the associated measurement times, can be determined from... Figure 4 Obtained from [the source].

[0110] The above method is performed under constant tank filling conditions, in which case the fuel level in tank 15 remains unchanged.

[0111] Only by performing pressure drop measurements, i.e., according to Figure 4 The second pressure drop measurement is used to shorten the diagnostic time of the aforementioned method or module 14 and / or device, such as... Figure 3 As shown in the image.

[0112] Figure 3 The values ​​Δp0 and Δp1 in the data correspond to... Figure 4 The values ​​Δp2 and Δp3 in the data are... Figure 4 The other two pressure drop measurements were not based on Figure 3 Execute in the method.

[0113] Under the worst-case approximation, i.e., the gas volume inside tank 15 is maximized, where the diameter d of the imaginary circular area of ​​the leak is... TL A value << 0.5mm can be used to determine whether the diameter of the leakage area of ​​the oil tank is << 0.5mm.

[0114] The only measured pressure drop is caused by fluid flowing out of the reference volume 11 and the tank 15 through the leakage area in the tank 15. At the end of this process, valve 9, the switching valve, should be checked to see if it has been closed again due to the pressure rise in the reference volume 11.

[0115] It can perform a reasonableness check on a defined area of ​​leakage.

[0116] The following simplified formula provides the calculated or estimated current gas volume V in tank 15:

[0117]

[0118] Therefore, it is possible to compare the currently measured gas volume with the level currently displayed by the vehicle's onboard computer and to check the reasonableness of the measurement results of the leak area.

[0119] Negative pressure can also be used for the methods and related diagnoses described herein. Optionally, negative pressure can also be conceived in relation to the generation of pressure mentioned in this specification.

[0120] Reference number list

[0121] 1. Atmospheric outlet

[0122] 2 pumps

[0123] 3. Pump motor of the pump

[0124] 4. Shut-off valve

[0125] 5. Reference partition

[0126] 6-module control equipment

[0127] 7. Interface of the module control device

[0128] 8. Pressure sensor

[0129] 9. Valves, switching valves

[0130] 10. Fuel tank interface

[0131] 11 Reference Volume

[0132] 12 Check valve

[0133] 13 Filters

[0134] 14 modules

[0135] 15 fuel tanks

[0136] 16 Activated Carbon Filter

[0137] 17. Motor, internal combustion engine

[0138] 18 Regeneration valve

[0139] 19 FTIV.

Claims

1. A module (14) for detecting leaks, comprising a pressure sensor (8) and a pump (2) for generating pressure. Its features are, The module (14) has a sealable reference volume (11) that is fluidly connected to the tank interface (10) via a valve (9) and is fluid-tightly separated from the tank interface. Pressure within the reference volume (11) can be detected by the pressure sensor (8). Pressure is generated within the reference volume (11) via a pump (2). The reference volume (11) is fluidly connected to and separated from the atmospheric outlet (1) via a shut-off valve (4) through a reference baffle (5) having a defined flow cross-section. In the first position of the valve (9), the tank interface (10) is connected to the atmosphere via the atmospheric outlet (1) and separated from the reference volume (11), and in the second position the tank interface is connected to the reference volume (11) and separated from the atmospheric outlet (1).

2. The module according to claim 1, characterized in that, The valve (9) is designed as a switching valve.

3. The module according to claim 1 or 2, characterized in that, A flow line extending from the reference volume (11) to the atmospheric outlet (1) is provided, and a reference baffle (5) having a defined flow cross-section is disposed in the flow line.

4. The module according to claim 1 or 2, characterized in that, The atmospheric outlet (1) leads into the filter (13), through which fluid can flow into the atmosphere.

5. The module according to claim 1 or 2, characterized in that, A check valve (12) is arranged between the reference volume (11) and the pump (2) to prevent backflow from the reference volume (11) to the pump (2).

6. The module according to claim 1 or 2, characterized in that... The system includes a base having a tank interface (10) for flange connection to a device having a tank (15), wherein the base has an atmospheric outlet (1) for discharging fluid into the atmosphere, and wherein the base has a module control device (6) having an interface (7) for connecting to electronic equipment of a motor vehicle or other system to output information about a leak.

7. An apparatus comprising a module (14) according to any one of the preceding claims and a fuel tank (15) of a motor vehicle, wherein the fuel tank is connected to the fuel tank interface (10) via an intermediate connection of an activated carbon filter (16), wherein, The pipeline leading from the activated carbon filter (16) to the motor (17) of the motor vehicle can be closed or opened via the regeneration valve (18).

8. A method for detecting leakage in a device having a tank (15) using a module (14) according to any one of claims 1 to 6, wherein the method measures a pressure drop of at least one of the reference volume (11) and the volume of the tank (15).

9. The method according to claim 8, characterized by the following steps: When the reference volume (11) under overpressure is connected to the atmosphere and fluid flows from the reference volume (11) into the atmosphere via the reference partition (5), a first pressure drop is detected by means of the pressure sensor (8). The second pressure drop in the reference volume (11) connected to the oil tank (15) and in an overpressure state is detected. The third pressure drop was detected, among which, A flow-guiding connection is created between the reference volume (11) under overpressure, the oil tank (15) connected to the reference volume, and the atmosphere, so that fluid from the oil tank and / or from the reference volume (11) can flow out to the atmosphere via the reference partition (5).

10. The method according to claim 8, characterized by the following steps: When the pump (2) is shut off, and the reference volume (11) is separated from the atmosphere and the oil tank (15), a flow-guiding connection is established between the oil tank (15) and the atmosphere. With the connection between the fuel tank (15) and the atmosphere separated, a flow-guiding connection is established between the reference volume (11) and the fuel tank (15), wherein, When the pump (2) is turned on, pressure is built up in the reference volume (11) and the oil tank (15). Maintain constant pressure when the pump (2) is turned on. Turn off the pump (2) and check for a pressure drop caused by a leak through the device or the oil tank (15) using the pressure sensor. When the pump (2) is shut off, while establishing a flow connection between the oil tank (15) and the atmosphere and establishing a flow connection between the reference volume (11) and the atmosphere, the flow connection between the reference volume (11) and the oil tank (15) is disconnected. With the flow connection between the oil tank (15) and the atmosphere separated, the flow connection between the reference volume (11) and the atmosphere also separated, and a flow connection is established between the oil tank (15) and the reference volume (11), so that when the pump (2) is turned off, the pressure rise in the reference volume (11) and the oil tank (15) is generated by the evaporation of the fluid. While establishing a flow connection between the oil tank (15) and the atmosphere, the flow connection between the reference volume (11) and the oil tank (15) is separated, thereby achieving venting of the oil tank (15) when the pump (2) is turned off, and establishing a flow connection between the reference volume (11) and the atmosphere when the pump (2) is turned off. When the pump (2) is shut off, the flow connection between the reference volume (11) and the atmosphere is disconnected and the offset of the pressure sensor is determined.

11. The method according to claim 8, characterized by the following steps: When the pump (2) is shut off, and the reference volume (11) is separated from the oil tank (15) and the atmosphere, a flow-guiding connection is established between the oil tank (15) and the atmosphere. When the pump (2) is turned on, a first pressure is established in the reference volume (11), which is separated from the oil tank (15) and the atmosphere in a sealed fluid manner. When the pump (2) is shut off, the pressure sensor (8) is used to check the sealing of the reference volume (11) and the module (14). When the pump (2) is turned on, a flow-guiding connection is established between the reference volume (11) and the atmosphere so that fluid can flow out into the atmosphere through the reference partition (5). To maintain a constant pressure relative to the reference diaphragm (5) constructed by the activated pump (2), The pump (2) is shut off and the pressure drop across the reference diaphragm (5) is checked using the pressure sensor (8). When the connection between the oil tank (15) and the reference volume (11) and the atmosphere is separated, a flow-guiding connection is established between the reference volume (11) and the oil tank (15), so that fluid can no longer flow out into the atmosphere via the reference partition (5), wherein, When the pump (2) is turned on, a second pressure is established in the reference volume (11) and the oil tank (15). Maintain constant pressure when the pump (2) is turned on. Turn off the pump (2) and check for a pressure drop caused by a leak in the device or the oil tank (15) using the pressure sensor. A flow-guiding connection is established between the reference volume (11), the oil tank (15), and the atmosphere so that fluid from the oil tank (15) and / or the reference volume (11) can flow out to the atmosphere via the reference baffle (5) when the pump (2) is turned on, wherein the pump (2) builds pressure. Maintain constant pressure when the pump (2) is turned on. While maintaining the flow connection between the reference volume (11), the oil tank (15), and the atmosphere, the pump (2) is shut off so that fluid from the oil tank and / or the reference volume (11) can flow out to the atmosphere via the reference baffle (5). With the connection between the oil tank (15) and the atmosphere established, the connection between the reference volume (11) and the oil tank (15) is separated, so that the fluid from the oil tank (15) can flow out into the atmosphere and the oil tank is vented when the pump (2) is turned off. With the flow connection between the oil tank (15) and the atmosphere separated, the flow connection between the reference volume (11) and the atmosphere also separated, and a flow connection is established between the oil tank (15) and the reference volume (11), such that when the pump (2) is turned off, a pressure rise is generated in the reference volume (11) and the oil tank (15) through fluid evaporation. While establishing a flow connection between the oil tank (15) and the atmosphere, the flow connection between the reference volume (11) and the oil tank (15) is separated, thereby achieving venting of the oil tank (15) when the pump (2) is turned off, and establishing a flow connection between the reference volume (11) and the atmosphere when the pump (2) is turned off. When the pump (2) is shut off, the flow connection between the reference volume (11) and the atmosphere is disconnected and the offset of the pressure sensor is determined.

12. The method according to any one of claims 8 to 11, characterized in that, The method is performed in a motor vehicle when the motor (17) is not running.

13. The method according to any one of claims 8 to 11, characterized in that, The module (14) quantitatively determines and / or outputs the leakage area of ​​the device.

14. The method according to any one of claims 8 to 11, characterized in that, Detect the diameter of the leak area with an accuracy of + / -15%.

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