Method for controlling the internal pressure of an operating fluid reservoir and operating fluid reservoir system with internal pressure control

Description

[0001] The present invention relates to a method for controlling the internal pressure of an operating fluid reservoir of a motor vehicle. Furthermore, the present invention relates to an operating fluid reservoir system.

[0002] In the following, reference is made to operating fluid containers designed as fuel containers or fuel tanks and to operating fluid container systems designed as fuel container systems. Operating fluid containers within the meaning of the invention are, in particular but not exclusively, fuel containers (for gasoline or diesel fuel) for motor vehicles, urea containers, windshield washer fluid containers, oil containers, auxiliary fluid containers, or additive containers for motor vehicles. Containers of the type mentioned above are frequently produced by extrusion blow molding, with HDPE (high-density polyethylene) being particularly suitable for the production of extrusion blow-molded containers. Furthermore, it is possible to produce corresponding operating fluid containers by means of an injection molding process. Furthermore, operating fluid containers made of metal can also be used.

[0003] In motor vehicles with an internal combustion engine, when heat is applied to a fuel tank, the fuel is also heated, causing the fuel's vapor pressure to rise and the fuel tank to be subjected to a corresponding internal pressure. The pressure increase within the fuel tank would continue until the internal pressure of the fuel tank equals the partial pressure of the fuel and pressure equilibrium is established. At high ambient temperatures, the partial pressure and the resulting internal pressure of the fuel tank are higher than at low ambient temperatures. Due to the corresponding internal pressurization, the fuel tank is subject to deformation.

[0004] To vent a fuel tank, the tank has at least one vent valve, which in turn is fluidly connected to a vent line for discharging excess pressure to the atmosphere. Particularly in a fuel tank designed for gasoline, its vent line is fluidly connected to an activated carbon filter for passing through and filtering out fuel vapors. The gases filtered by the activated carbon filter are released into the atmosphere after passing through the activated carbon filter. The activated carbon filter is purged by intake air during operation of the internal combustion engine, so that fuel vapors bound in the activated carbon can be fed to the internal combustion engine. Due to the purging process with intake air, the absorption capacity of the activated carbon filter can be limited.

[0005] Motor vehicles with hybrid drive systems, i.e., those with both an internal combustion engine and an electric motor, require a fuel tank that can withstand increased internal pressures. In such hybrid vehicles, the activated carbon filter fluidly connected to the fuel tank is flushed less frequently due to the reduced operating time of the internal combustion engine, meaning that less fuel vapor bound in the activated carbon can be flushed out. Furthermore, venting the fuel tank via the activated carbon filter converts more fuel into the vapor phase, so it would be advantageous to make the fuel tank more rigid and / or more pressure-resistant.

[0006] Consequently, fuel tanks designed for hybrid vehicles require different vent valves than fuel tanks designed for conventional vehicles, i.e., vehicles with only an internal combustion engine. This is because the maximum internal pressure for a fuel tank for a hybrid vehicle is greater than the maximum internal pressure for a fuel tank for a conventional vehicle, so different vent valves must be installed. Therefore, a manufacturer of fuel tanks, and of operating fluid tanks in general, must design and stock a variety of differently designed vent valves, which leads to increased manufacturing effort and costs.

[0007] Examples of methods for controlling the internal pressure of an operating fluid reservoir of a motor vehicle are also known from DE19930926A1, DE102015012656A1 and DE102010054960A1.

[0008] The present invention is based on the object of providing a method for controlling the internal pressure of an operating fluid container, by which the complexity and manufacturing costs of an operating fluid container are reduced. Furthermore, the present invention is based on the object of providing an operating fluid container system that has reduced manufacturing complexity and costs.

[0009] The object underlying the present invention is achieved by a method for controlling the internal pressure of an operating fluid container having the features of claim 1. Advantageous embodiments of the method according to the invention are disclosed in the claims dependent on claim 1.

[0010] The object underlying the present invention is further achieved by an operating fluid container system having the features of claim 4. Advantageous embodiments of the operating fluid container system according to the invention are disclosed in the claims dependent on claim 4.

[0011] A method for controlling the internal pressure of an operating fluid reservoir of a motor vehicle preferably comprises the following method steps: Determining an internal pressure of the operating fluid container by means of a pressure sensor arranged in an operating fluid container interior; comparing the determined internal pressure with a predetermined maximum internal pressure by means of an electronic control device; outputting an opening signal from the control device to a vent valve arranged in a vent line or between the operating fluid container interior and the vent line, wherein the vent line fluidically connects the operating fluid container interior to the atmosphere when the determined internal pressure is equal to or greater than the maximum internal pressure; and transferring the vent valve to an open position in which the operating fluid container interior is fluidly connected to the atmosphere by means of the vent valve, upon receipt of the opening signal.

[0012] Such a method ensures that a vent valve of one type can be used for different operating fluid reservoirs, each of which is designed for different maximum internal pressures, which can also be referred to as limit pressures. The same applies to the electronic control device, which is connected to the vent valve and the pressure sensor via a data line for data exchange. The electronic control device can also be used for different operating fluid reservoirs; for different operating fluid reservoirs with different maximum internal pressures, only the maximum internal pressure needs to be stored accordingly in the electronic control device or in a memory device to which the electronic control device has access.

[0013] The internal pressure control method may also be referred to as a working fluid tank vent control method.

[0014] The operating fluid container is preferably a fuel container, which can also be referred to as a fuel tank. The fuel container is preferably designed to hold gasoline. The fuel container is also preferably designed to hold diesel fuel.

[0015] The internal pressure of the operating fluid reservoir is the pressure within the operating fluid reservoir, i.e. the pressure in the interior of the operating fluid reservoir.

[0016] The pressure sensor can also be called an internal pressure sensor.

[0017] The predetermined maximum internal pressure, which may also be referred to as limit internal pressure, is preferably stored in the electronic control device, more precisely in a memory device which is integrated in the electronic control device or to which the electronic control device has access.

[0018] The electronic control device is preferably a data-processing control device. The control device can be a separate control device of the operating fluid reservoir or an operating fluid reservoir system and / or a control device of the motor vehicle in which the operating fluid reservoir is installed.

[0019] The vent valve is a vent valve for the operating fluid reservoir. The vent valve can be in an open position and a closed position. In the open position, the interior of the operating fluid reservoir is fluidly connected to the atmosphere by means of the vent line and the vent valve. Preferably, an adsorption filter for adsorbing hydrocarbons is additionally arranged in the vent path formed by the vent line and the vent valve, i.e., the interior of the operating fluid reservoir is fluidly connected to the adsorption filter, and this is fluidly connected to the atmosphere. The interior of the operating fluid reservoir is thus vented via the adsorption filter. In the closed position of the vent valve, the interior of the operating fluid reservoir is fluidly separated from the atmosphere.In the case that an adsorption filter is arranged in the venting path, the operating fluid container interior is fluidly separated from the adsorption filter in the closed position of the venting valve.

[0020] Preferably, the method comprises the following method steps: Comparing the determined internal pressure with a predetermined minimum internal pressure by means of the electronic control device; outputting an opening signal from the control device to the vent valve when the determined internal pressure is equal to or less than the minimum internal pressure; and transferring the vent valve to the open position, in which the operating fluid container interior is fluidly separated from the atmosphere by means of the vent valve, upon receipt of the opening signal.

[0021] A service fluid reservoir is subject to negative pressure when service fluid is pumped out of the reservoir and / or when service fluid, e.g., fuel, condenses. The correspondingly designed method offers the advantage of protecting the service fluid reservoir from excessive negative pressure. Furthermore, the correspondingly designed method allows a single vent valve to be used for different service fluid reservoirs, each of which is designed for different minimum internal pressures. The same applies to the electronic control device, which is connected to the vent valve and the pressure sensor via a data line for data exchange.The electronic control device can also be used for different operating fluid containers, whereby for different operating fluid containers with different minimum internal pressures, only the minimum internal pressure needs to be stored accordingly in the electronic control device or in a storage device to which the electronic control device has access.

[0022] The object underlying the present invention is achieved by a method for controlling the internal pressure of an operating fluid container of a motor vehicle, wherein the method according to the invention comprises the following method steps: Determining an internal pressure of the operating fluid container by means of a pressure sensor arranged in an operating fluid container interior; determining an ambient pressure of the operating fluid container by means of an ambient pressure sensor; determining a differential pressure between the internal pressure and the ambient pressure by means of an electronic control device; comparing the differential pressure with a predetermined maximum differential pressure by means of the control device; outputting an opening signal from the control device to a vent valve arranged in a vent line or between the operating fluid container interior and the vent line, wherein the vent line fluidically connects the operating fluid container interior to the atmosphere, when the determined differential pressure is equal to or greater than the maximum differential pressure;and transferring the vent valve to an open position in which the interior of the operating fluid reservoir is fluidly connected to the atmosphere by means of the vent valve upon receipt of the opening signal. ;

[0023] By means of the appropriately designed method according to the invention, exceeding an overpressure that would be harmful to the operating fluid reservoir can be prevented with even greater accuracy and reliability. This is because the ambient pressure of the operating fluid reservoir, which counteracts the internal pressure of the operating fluid reservoir, is also taken into account for controlling the vent valve. Thus, the vent valve is moved to its open position depending on the ambient pressure.

[0024] The correspondingly designed method also ensures that a vent valve of one type can be used for different operating fluid reservoirs, each of which is designed for different maximum internal pressures. The same applies to the electronic control device, which is connected to the vent valve, the pressure sensor, and the ambient pressure sensor via a data line for data exchange. The electronic control device can also be used for different operating fluid reservoirs; for different operating fluid reservoirs with different maximum differential pressures, only the maximum differential pressure needs to be stored accordingly in the electronic control device or in a memory device to which the electronic control device has access.

[0025] The internal pressure control method may also be referred to as a working fluid tank vent control method.

[0026] The operating fluid container is preferably a fuel container, which can also be referred to as a fuel tank. The fuel container is preferably designed to hold gasoline. The fuel container is also preferably designed to hold diesel fuel.

[0027] The internal pressure of the operating fluid reservoir is the pressure within the operating fluid reservoir, i.e., the pressure inside the operating fluid reservoir. The pressure sensor can also be referred to as an internal pressure sensor.

[0028] The ambient pressure of the operating fluid reservoir is the external pressure, or atmospheric pressure. The differential pressure is therefore calculated by subtracting the ambient pressure from the internal pressure. The ambient pressure sensor can also be referred to as an external pressure sensor. The ambient pressure sensor is located outside the interior of the operating fluid reservoir.

[0029] The predetermined maximum differential pressure, which may also be referred to as limit differential pressure, is preferably stored in the electronic control device, more precisely in a memory device which is integrated in the electronic control device or to which the electronic control device has access.

[0030] The electronic control device is preferably a data-processing control device. The control device can be a separate control device of the operating fluid reservoir or an operating fluid reservoir system and / or a control device of the motor vehicle in which the operating fluid reservoir is installed.

[0031] The vent valve is a vent valve for the operating fluid reservoir. The vent valve can be in an open position and a closed position. In the open position, the interior of the operating fluid reservoir is fluidly connected to the atmosphere by means of the vent line and the vent valve. Preferably, an adsorption filter for adsorbing hydrocarbons is additionally arranged in the vent path formed by the vent line and the vent valve, i.e., the interior of the operating fluid reservoir is fluidly connected to the adsorption filter, and this is fluidly connected to the atmosphere. The interior of the operating fluid reservoir is thus vented via the adsorption filter. In the closed position of the vent valve, the interior of the operating fluid reservoir is fluidly separated from the atmosphere.In the case that an adsorption filter is arranged in the venting path, the operating fluid container interior is fluidly separated from the adsorption filter in the closed position of the venting valve.

[0032] The process also includes the following steps: Comparing the differential pressure with a predetermined minimum differential pressure by means of the control device; outputting an opening signal from the control device to the vent valve when the determined differential pressure is equal to or less than the minimum differential pressure; and transferring the vent valve to the open position, in which the interior of the operating fluid container is fluidly connected to the atmosphere by means of the vent valve, upon receipt of the opening signal.

[0033] By means of the appropriately designed method according to the invention, a negative pressure that would be detrimental to the operating fluid reservoir can be prevented with even greater accuracy and reliability. This is because the ambient pressure of the operating fluid reservoir, which counteracts the internal pressure of the operating fluid reservoir, is also taken into account when controlling the vent valve. Thus, the vent valve is moved to its open position depending on the ambient pressure.

[0034] A service fluid reservoir is subject to negative pressure when service fluid is pumped out of the reservoir and / or when service fluid vapor, e.g., fuel vapor, condenses. The correspondingly designed method offers the advantage of protecting the service fluid reservoir from excessive negative pressure. Furthermore, the correspondingly designed method allows a single vent valve to be used for different service fluid reservoirs, each of which is designed for different minimum differential pressures. The same applies to the electronic control device, which is connected to the vent valve, the pressure sensor, and the ambient pressure sensor via a data line for data exchange.The electronic control device can also be used for different operating fluid containers, whereby for different operating fluid containers with different minimum differential pressures, only the minimum differential pressure needs to be stored accordingly in the electronic control device or in a storage device to which the electronic control device has access.

[0035] Preferably, the method is designed such that in the method step of transferring the vent valve into its open position, the vent valve is gradually transferred into its open position.

[0036] A gradual transfer of the vent valve into its open position is understood to mean a gradual transfer of the vent valve into its open position, in which a venting cross-section of the vent valve is continuously increased over a predetermined time up to a maximum achievable venting cross-section.

[0037] For example, upon receipt of the opening signal, the venting cross-section of the venting valve can be set to, for example, 10% (more or less is also possible) of the maximum achievable venting cross-section for a predetermined time before the venting valve is completely moved to its open position.

[0038] With a corresponding design of the method, pressure peaks are avoided during venting and / or ventilation of the operating fluid tank, which is particularly advantageous for fuel tanks designed for hybrid vehicles, since a relatively high overpressure or underpressure can build up in these tanks.

[0039] Preferably, the method is designed such that it comprises the following method steps: Determining whether a regeneration valve arranged in a purge line or between a purge connection of an adsorption filter and the purge line is in an open position, wherein the purge line fluidically connects an adsorption filter interior to an intake tract of an internal combustion engine of the motor vehicle; outputting a closing signal from the control device to the vent valve when the regeneration valve is in the open position; and transferring the vent valve to a closed position, in which the operating fluid reservoir interior is fluidly separated from the atmosphere by means of the vent valve, upon receipt of the closing signal.

[0040] The correspondingly designed process offers the advantage that no unnecessary negative pressure is generated in the operating fluid reservoir. Furthermore, the correspondingly designed process offers the advantage that the composition of the fuel mixture drawn into the internal combustion engine via its intake tract does not change suddenly, thus achieving a more consistent exhaust gas quality.

[0041] When the regeneration valve is in its open position, the adsorption filter is flushed by the engine's intake air while the engine is running. Consequently, a flushing process is then performed on the adsorption filter to release hydrocarbons from the adsorption material in the adsorption filter.

[0042] In general, the first feature can also be formulated as follows: Determine whether a fluid connection exists / is established between a purge connection of the adsorption filter and an intake tract of the internal combustion engine.

[0043] Another formulation of the first feature can also be as follows: Determining whether a regeneration valve arranged in a purge path between an adsorption filter and an intake tract of the internal combustion engine is in an open position.

[0044] Alternatively, the first feature can also be formulated as follows: Determine whether a flushing process of the adsorption filter is carried out.

[0045] The object underlying the present invention is further achieved by an operating fluid container system comprising the following: at least one operating fluid container; at least one pressure sensor arranged in an operating fluid container interior for determining an internal pressure of the operating fluid container interior; a vent line that fluidically connects the operating fluid container interior to the atmosphere; an electrically actuated vent valve that can be actuated in the vent line and between an open position, in which the operating fluid container interior is fluidly connected to the atmosphere, and a closed position, in which the operating fluid container interior is fluidly separated from the atmosphere by means of the vent valve; and an electronic control device that is connected to the pressure sensor and the vent valve via a data line and is designed to carry out a method according to one of claims 1 and / or 2.

[0046] The operating fluid reservoir system according to the invention offers the advantage that a vent valve of one design can be used for different operating fluid reservoirs, each designed for different maximum internal pressures. The same applies to the electronic control device, which is connected to the vent valve and the pressure sensor via a data line for data exchange. The electronic control device can also be used for different operating fluid reservoirs, whereby for different operating fluid reservoirs with different maximum internal pressures, only the maximum internal pressure needs to be stored accordingly in the electronic control device or in a memory device to which the electronic control device has access.

[0047] The operating fluid container is preferably a fuel container, which can also be referred to as a fuel tank. The fuel container is preferably designed to hold gasoline. The fuel container is also preferably designed to hold diesel fuel.

[0048] The predetermined maximum internal pressure, which may also be referred to as limit internal pressure, is preferably stored in the electronic control device, more precisely in a memory device which is integrated in the electronic control device or to which the electronic control device has access.

[0049] The electronic control device is preferably a data-processing control device. The control device can be a separate control device of the operating fluid reservoir or an operating fluid reservoir system and / or a control device of the motor vehicle in which the operating fluid reservoir is installed.

[0050] The vent valve is a vent valve for the operating fluid reservoir. The vent valve can be in an open position and a closed position. In the open position, the interior of the operating fluid reservoir is fluidly connected to the atmosphere by means of the vent line and the vent valve. Preferably, an adsorption filter for adsorbing hydrocarbons is additionally arranged in the vent path formed by the vent line and the vent valve, i.e., the interior of the operating fluid reservoir is fluidly connected to the adsorption filter, and this is fluidly connected to the atmosphere. The interior of the operating fluid reservoir is thus vented via the adsorption filter. In the closed position of the vent valve, the interior of the operating fluid reservoir is fluidly separated from the atmosphere.In the case that an adsorption filter is arranged in the venting path, the operating fluid container interior is fluidly separated from the adsorption filter in the closed position of the venting valve.

[0051] The operating fluid reservoir system has an ambient pressure sensor for determining an ambient pressure of the operating fluid reservoir.

[0052] Preferably, the electronic control device is designed to carry out a method according to claim 3.

[0053] The appropriately designed operating fluid reservoir system offers the advantage of protecting the operating fluid reservoir from excessive negative pressure. Furthermore, the appropriately designed operating fluid reservoir system allows a single vent valve to be used for different operating fluid reservoirs, each designed for different minimum internal pressures. The same applies to the electronic control unit, which is connected to the vent valve and the pressure sensor via a data line for data exchange.The electronic control device can also be used for different operating fluid containers, whereby for different operating fluid containers with different minimum internal pressures, only the minimum internal pressure needs to be stored accordingly in the electronic control device or in a storage device to which the electronic control device has access.

[0054] The ambient pressure sensor is preferably located outside the interior of the operating fluid tank.

[0055] Further preferably, the operating fluid container system comprises an adsorption filter which is fluidly connected to the vent line by means of an inlet connection and to the atmosphere by means of an outlet connection, wherein the electronic control device is designed to carry out the following method steps: Determining whether a regeneration valve arranged in a purge line or between a purge connection of an adsorption filter and the purge line is in an open position, wherein the purge line fluidically connects an adsorption filter interior to an intake tract of an internal combustion engine of the motor vehicle; outputting a closing signal from the control device to the vent valve when the regeneration valve is in the open position; and transferring the vent valve to a closed position, in which the operating fluid reservoir interior is fluidly separated from the atmosphere by means of the vent valve, upon receipt of the closing signal.

[0056] The appropriately designed operating fluid reservoir system offers the advantage of preventing unnecessary negative pressure from building up in the operating fluid reservoir. Furthermore, it ensures that the composition of the fuel mixture drawn into the internal combustion engine through its intake tract does not change suddenly, thus achieving a more consistent exhaust quality.

[0057] When the regeneration valve is in its open position, the adsorption filter is flushed by the engine's intake air while the engine is running. Consequently, a flushing process is then performed on the adsorption filter to release hydrocarbons from the adsorption material in the adsorption filter.

[0058] The adsorption filter, which is preferably designed as an activated carbon filter, has an inlet connection for the fluid connection with the vent line and an outlet connection for the fluid connection with the atmosphere.

[0059] Preferably, a shut-off valve is arranged between the outlet connection of the adsorption filter and the atmosphere, which shut-off valve can further preferably be actuated electrically, ie electromechanically and / or electromagnetically, between an open position and a closed position.

[0060] Further preferably, the operating fluid container system comprises an overpressure protection valve arranged in the vent line or between the operating fluid container interior and the vent line. The overpressure protection valve is movable between an open position, in which gas exchange is enabled by the overpressure protection valve, and a closed position, in which gas exchange is prevented by the overpressure protection valve. The overpressure protection valve is in its closed position when the internal pressure in the operating fluid container interior is less than the maximum pressure, and the overpressure protection valve is moved to its open position when the internal pressure in the operating fluid container interior is greater than the maximum pressure.

[0061] The appropriately designed operating fluid reservoir system offers the advantage that in the event of a power failure, for example, if the battery used to operate the vent valve is dead due to the vehicle being idle for a long time, no excess pressure can build up in the operating fluid reservoir beyond the maximum pressure. This is particularly advantageous for a vent valve that is in its closed position when de-energized.

[0062] The overpressure protection valve is therefore connected in parallel to the vent valve.

[0063] The overpressure protection valve is a passive overpressure protection valve. This means that the valve body of the overpressure protection valve is not electrically (i.e., neither electromechanically nor electromagnetically) moved but only by a pressure difference.

[0064] In the open position of the overpressure protection valve, a valve body of the overpressure protection valve is spaced from a valve seat of the overpressure protection valve. In the closed position of the overpressure protection valve, the valve body of the overpressure protection valve closes the valve seat of the overpressure protection valve.

[0065] Further preferably, the operating fluid container system comprises a vacuum protection valve arranged in the vent line or between the operating fluid container interior and the vent line (70), wherein the vacuum protection valve is movable between an open position, in which gas exchange is enabled by the vacuum protection valve, and a closed position, in which gas exchange is prevented by the vacuum protection valve. The vacuum protection valve is in its closed position when the internal pressure in the operating fluid container interior is greater than the minimum pressure, and the vacuum protection valve is transferred to its open position when the internal pressure in the operating fluid container interior is less than the minimum pressure.

[0066] The appropriately designed operating fluid reservoir system offers the advantage that in the event of a power failure, for example, if the battery used to operate the vent valve is dead due to the vehicle being idle for a long time, a vacuum cannot build up in the operating fluid reservoir that falls below the minimum internal pressure. This is particularly advantageous for a vent valve that is in its closed position when de-energized.

[0067] The vacuum protection valve is therefore connected in parallel to the vent valve.

[0068] The vacuum protection valve is a passive vacuum protection valve. This means that the valve body of the vacuum protection valve is not electrically (i.e., neither electromechanically nor electromagnetically) moved, but only by a pressure difference.

[0069] In the open position of the vacuum protection valve, a valve body of the vacuum protection valve is spaced from a valve seat of the vacuum protection valve. In the closed position of the vacuum protection valve, the valve body of the vacuum protection valve closes the valve seat of the vacuum protection valve.

[0070] Further preferably, the operating fluid container system has a filler pipe opening into the operating fluid container interior and a refueling vent line that is fluidly connected to the operating fluid container interior and the filler pipe. The electrically actuated vent valve is designed as an operating and / or refueling vent valve with an operating vent inlet connection, an operating vent outlet connection, a refueling vent inlet connection, and a refueling vent outlet connection. The operating vent inlet connection and the refueling vent inlet connection are each fluidly connected to the operating fluid container interior, the operating vent outlet connection is fluidly connected to the atmosphere, and the refueling vent outlet connection is fluidly connected to the filler pipe.The operating and / or refueling vent valve is electrically operable between a ventilation position, a refueling position, and a closed position. In the ventilation position, the operating fluid container interior is fluidly connected to the atmosphere and to the filler pipe by means of the operating and / or refueling vent valve. In the refueling position, the operating fluid container interior is fluidly separated from the atmosphere by means of the operating and / or refueling vent valve and fluidly connected to the filler pipe by means of the operating and / or refueling vent valve. In the closed position, the operating fluid container interior is fluidly separated from the atmosphere and the filler pipe by means of the operating and / or refueling vent valve.

[0071] Preferably, the operating vent outlet port is fluidly connected to the atmosphere via an adsorption filter. Consequently, during an operating vent, the gas escaping from the operating fluid reservoir is passed through the adsorption filter.

[0072] Further advantages, details, and features of the invention will become apparent from the following exemplary embodiments. In particular, they show: Figure 1: a process flow chart of a method for controlling the internal pressure of an operating fluid container according to a first embodiment; Figure 2: a process flow chart of a further method for controlling the internal pressure of an operating fluid container according to a second embodiment; Figure 3: a process flow chart of a further method for controlling the internal pressure of an operating fluid container according to a third embodiment; Figure 4: a process flow chart of a method according to the invention according to a fourth embodiment of the present invention; Figure 5: a process flow chart of a method according to the invention according to a fifth embodiment of the present invention; Figure 6: an operating fluid container system according to the invention according to a sixth embodiment of the present invention; Figure 7: an operating fluid container system according to the invention according to a seventh embodiment of the present invention;Figure 8: an operating fluid container system according to an eighth embodiment of the present invention; and Figure 9: an operating fluid container system according to a ninth embodiment of the present invention.

[0073] In the following description, identical reference numerals designate identical components or identical features, so that a description given with reference to one figure regarding a component also applies to the other figures, thus avoiding repetitive description. Furthermore, individual features described in connection with one embodiment can also be used separately in other embodiments.

[0074] Figure 1 shows a process flow chart of a method for controlling the internal pressure of an operating fluid container according to a first embodiment.

[0075] In a first process step A, an internal pressure of an operating fluid container 10 (see Figures 5 to 8 ). The internal pressure can be determined, for example, by means of a pressure sensor 15 arranged in the interior 11 of the operating fluid reservoir. Alternatively, the pressure sensor 15 can also be arranged in a filler pipe 12.

[0076] In a second method step B1, the determined internal pressure is compared with a predetermined maximum internal pressure. This comparison can preferably be performed using an electronic control device. If the determined internal pressure is less than the predetermined maximum internal pressure, the process returns to the first method step A.

[0077] If, however, the determined internal pressure is equal to or greater than the maximum internal pressure, an opening signal is output in a third method step C. The opening signal is preferably output to a vent valve 20 by means of the electronic control device. As can be seen from the Figures 6 to 9 As can be seen, the vent valve 20 is arranged in a vent line 70 or between the operating fluid container interior 11 and the vent line 70, wherein the vent line 70 fluidly connects the operating fluid container interior 11 to the atmosphere.

[0078] Upon receipt of the opening signal, in a fourth method step the vent valve 20 is moved into an open position in which the operating fluid container interior 11 is fluidly connected to the atmosphere by means of the vent valve 20.

[0079] Figure 2shows a process flow chart of a further method for internal pressure control of an operating fluid container according to a second embodiment.

[0080] The first method step A and the second method step B2 are identical to the method according to the first embodiment. If it is determined in the second method step B1 that the determined internal pressure is less than the maximum internal pressure, i.e., if the determined internal pressure is not equal to the maximum pressure and not greater than the maximum internal pressure, a fifth method step B2 is executed, in which the determined internal pressure is compared with a predetermined minimum internal pressure. The fifth method step B2 is preferably carried out by means of the electronic control device.

[0081] If it is determined in the fifth method step B2 that the determined internal pressure is not equal to the minimum internal pressure or greater than the minimum internal pressure, the process returns to the first method step A. If, on the other hand, it is determined in the fifth method step B2 that the determined internal pressure is equal to the minimum internal pressure or less than the minimum internal pressure, the third method step C is carried out, i.e. an opening signal is output to the vent valve 20. This method step is preferably carried out by the electronic control device. Subsequently, the fourth method step D is carried out, according to which the vent valve 20 is moved into the open position upon receipt of the opening signal, wherein in the open position of the vent valve 20 the operating fluid container interior 11 is fluidly connected to the atmosphere by means of the vent valve 20.

[0082] By means of the method according to the second embodiment of the present invention, it is thus achieved that the internal pressure of the operating fluid container 10 is in a predetermined pressure range, wherein the predetermined pressure range is limited by the minimum internal pressure and by the maximum internal pressure.

[0083] Figure 3 shows a process flow chart of a further method for controlling the internal pressure of an operating fluid container according to a third embodiment.

[0084] In a first method step A1, the internal pressure of the operating fluid reservoir 10 is determined. The internal pressure is determined using a pressure sensor 15 arranged in the interior space 11 of the operating fluid reservoir.

[0085] Subsequently, in a second method step A2, the ambient pressure of the operating fluid reservoir 10 is determined. The ambient pressure is determined by means of an ambient pressure sensor 16, which is arranged outside the interior space 11 of the operating fluid reservoir.

[0086] In a third method step A3, a differential pressure between the internal pressure and the ambient pressure is determined, with the third method step preferably being carried out by means of the electronic control device. The differential pressure is thus obtained by subtracting the determined ambient pressure from the determined internal pressure.

[0087] In a fourth method step B3, which is preferably also carried out by the electronic control device, the differential pressure is compared with a predetermined maximum differential pressure. If the differential pressure is less than the maximum differential pressure, the system returns to the first method step A1.

[0088] If, however, it is determined in the fourth method step B3 that the determined differential pressure is equal to or greater than the maximum differential pressure, a fifth method step C1 is executed, according to which an opening signal is output to the vent valve 20. The opening signal is output by the electronic control device. The vent valve 20 is arranged in the vent line 70 or between the interior space 11 of the operating fluid reservoir and the vent line 70. Consequently, the interior space 11 of the operating fluid reservoir is fluidly connected to the atmosphere via the vent line 70.

[0089] Upon receipt of the opening signal, in a sixth method step the vent valve 20 is moved into its open position, in which the operating fluid container interior 11 is fluidly connected to the atmosphere by means of the vent valve 20.

[0090] Figure 4 shows a process flow chart of a method according to the invention according to a fourth embodiment of the present invention.

[0091] The first four method steps, ie the first method step A1, the second method step A2, the third method step A3 and the fourth method step B3 of the method according to the fourth embodiment are identical to the first four method steps of the third embodiment.

[0092] If it is determined in the fourth method step B3 that the determined differential pressure is less than the maximum differential pressure, a method step B4 is executed, according to which the differential pressure is compared with a predetermined minimum differential pressure. If the minimum differential pressure is greater than the minimum differential pressure, the process returns to the first method step A1.

[0093] If, however, it is determined in the seventh method step B4 that the differential pressure is equal to or less than the minimum differential pressure, the fifth method step C1 is executed, according to which an opening signal is output from the control device to the vent valve 20 by means of the electronic control device. Subsequently, in the sixth method step D, upon receipt of the opening signal, the vent valve 20 is moved to its open position, in which the operating fluid reservoir interior 11 is fluidly connected to the atmosphere by means of the vent valve 20.

[0094] Figure 5 shows a process flow chart of a method according to the invention according to a fifth embodiment of the present invention.

[0095] The method according to the fifth embodiment of the present invention follows method step D of the previous embodiments, according to which the vent valve 20 is transferred to its open position upon receipt of an opening signal.

[0096] In an eighth method step, it is determined whether a regeneration valve 50 arranged in a purge line 72 or between a purge connection 83 of an adsorption filter 80 and the purge line 72 is in an open position, wherein the purge line 72 fluidically connects an adsorption filter interior to an intake tract of an internal combustion engine of the motor vehicle. Subsequently, in a ninth method step F, a closing signal is output from the control device to the vent valve 20 if the regeneration valve 50 is in the open position. In a tenth method step G, upon receipt of the closing signal by the vent valve 20, the vent valve 20 is moved into a closed position in which the operating fluid reservoir interior 11 is fluidly separated from the atmosphere by means of the vent valve 20.

[0097] In Figure 6An operating fluid container system 1 according to a sixth embodiment of the present invention is shown, wherein the operating fluid container system 1 is designed to carry out a method according to one of the first to fifth embodiments. This is Figure 6 The operating fluid container system shown is designed as a so-called onboard refueling vapor recovery system.

[0098] The operating fluid tank system 1 has an operating fluid tank 10, which in the present exemplary embodiment and in the subsequent exemplary embodiments is designed as a fuel tank 10. A pressure sensor 15 for determining an internal pressure of the operating fluid tank interior 11 is arranged in an operating fluid tank interior 11 of the operating fluid tank 10. In the illustrated exemplary embodiment, the operating fluid tank 10 is designed as a saddle tank 10, with a fill level sensor 17 being arranged in each of the two main volumes of the operating fluid tank 10 for determining a fill level in the two main volumes of the operating fluid tank 10.

[0099] In the illustrated embodiment, the interior space 11 of the operating fluid reservoir is vented via a vent line 70, 71, which in the illustrated embodiment is designed as an operating and / or refueling vent line 70, 71 and is therefore suitable for venting during operation as well as during a refueling process. A vent valve 20, 30 is arranged in the vent line 70, 71, which in the illustrated embodiment is designed as an operating and / or refueling vent valve 20, 30.

[0100] The operating fluid reservoir system 1 has a filler pipe 12 which opens into the operating fluid reservoir interior 11. The filler pipe 12 can be closed by a filler pipe closure 13. Furthermore, Figure 6It can be seen that the operating fluid container system 1 further comprises a tank flap 14, behind which a filler neck is arranged on one side of the filler pipe 12. When a nozzle is inserted into the filler pipe 12 via the filler neck, a gas flow is controlled by means of a gas flow control element 23. The gas flow can be controlled such that the entire gas flow is directed to an adsorption filter 80. Furthermore, the gas flow can be controlled such that a portion of the gas flow is recirculated into the operating fluid container interior 11. The gas flow can also be controlled such that when a nozzle is inserted into the filler pipe 12, the entire gas flow is directed out of the filler neck of the filler pipe 12.Furthermore, it is also possible for the gas flow to be controlled such that, when the nozzle is inserted into the filler pipe 12, a portion of the gas flow is directed to the adsorption filter 80, and a remaining gas flow is discharged from the filler pipe 12. If no nozzle is inserted into the filler pipe 12, a gas flow is always directed to the adsorption filter 80 through the gas flow control element 23 during operation.

[0101] The operating fluid container system 1 has an overpressure protection valve 21 arranged in the vent line 70, 71. The overpressure protection valve 21 is movable or variable between an open position, in which gas exchange is enabled by the overpressure protection valve 21, and a closed position, in which gas exchange is prevented by the overpressure protection valve 21. The overpressure protection valve 21 is in its closed position when the internal pressure in the operating fluid container interior 11 is less than a predetermined maximum pressure. Conversely, the overpressure protection valve 21 is in its open position when the internal pressure in the operating fluid container interior 11 is greater than the maximum pressure. The operating fluid container system 1 further has a vacuum protection valve 22 arranged in the vent line 70, 71.The vacuum protection valve 21 is movable or variable between an open position, in which gas exchange is enabled through the vacuum protection valve 21, and a closed position, in which gas exchange is prevented through the vacuum protection valve 21. The vacuum protection valve 22 is in its closed position when the internal pressure in the interior 11 of the operating fluid reservoir is greater than the minimum pressure. When the internal pressure in the interior 11 of the operating fluid reservoir is less than the minimum pressure, the vacuum protection valve 22 is moved to its open position.

[0102] As from Figure 6As can be seen, the operating fluid container system 1 further comprises an ambient pressure sensor 16, which is arranged outside the operating fluid container interior 11. By means of the internal pressure determined by the pressure sensor 15 and by means of the ambient pressure determined by the ambient pressure sensor 16, a differential pressure between the internal pressure and the ambient pressure can thus be determined.

[0103] The adsorption filter 80 is fluidically connected to the operating fluid container interior 11 via an inlet connection 81. Furthermore, the adsorption filter 80 has an outlet connection 82, via which the adsorption filter 80 is fluidically connected to the atmosphere. As can be seen from Figure 6As can be seen, a tank isolation valve 60 is arranged between the atmosphere and the outlet connection 82 of the adsorption filter 80. In an open position of the tank isolation valve 60, the adsorption filter interior is fluidly connected to the atmosphere, whereas in a closed position of the tank isolation valve 60, the adsorption filter interior is fluidly separated from the atmosphere. The adsorption filter 80 further has a purge connection 83, by means of which the adsorption filter interior is fluidly connected via a purge line 72 to an intake tract of an internal combustion engine of a motor vehicle in which the operating fluid container system 1 is installed. A regeneration valve 50 is arranged between the purge connection 83 and the intake tract of the internal combustion engine (not shown).In an open position of the regeneration valve 50, the adsorption filter interior is fluidly connected to the intake tract, whereas in a closed position of the regeneration valve 50, the adsorption filter interior is fluidly separated from the intake tract.

[0104] The vent valve 20, or the operating and / or refueling vent valve 20, 30, the regeneration valve 50, and the tank isolation valve 60 are each designed as electrically actuated valves. Consequently, these valves can be adjusted electrically, i.e., electromechanically and / or electromagnetically, between an open position and a closed position. These valves are each connected via data lines to an electronic control device (not shown in the figures). Furthermore, the internal pressure sensor 15 and the ambient pressure sensor 16 are also connected to the electronic control device via data lines (not shown in the figures) for data exchange. The same applies to the fill level sensors 17, which are connected to the electronic control device via data lines for data exchange.The electronic control device is designed to carry out the methods described in the first to fifth embodiments.

[0105] In Figure 71 shows an operating fluid container system 1 according to a seventh embodiment of the present invention. In the operating fluid container system 1 according to the seventh embodiment, the operating fluid container 10 is not designed as a saddle tank in which only a fill level sensor 17 is arranged. The vent valve 20 is designed as an operating vent valve 20 and is arranged in the vent line 70, which is designed as an operating vent line 70. The overpressure protection valve 21 and the underpressure protection valve 22 are also arranged in the operating vent line 70 and are each movable between an open position, in which gas exchange through the respective valve is possible, and a closed position, in which gas exchange through the respective valve is prevented.The overpressure protection valve 21 is in its closed position when the internal pressure in the operating fluid reservoir interior 11 is less than the maximum pressure. The overpressure protection valve 21 is moved to its open position when the internal pressure in the operating fluid reservoir interior 11 is greater than the maximum pressure. The vacuum protection valve 22 is in its closed position when the internal pressure in the operating fluid reservoir interior 11 is greater than the minimum pressure. When the internal pressure in the operating fluid reservoir interior 11 is less than the minimum pressure, the vacuum protection valve 22 is moved to its open position.

[0106] The operating fluid container interior 11 is furthermore connected to the filler pipe 12 via a refueling vent line 71 for discharging gases during a refueling process, wherein the gases discharged from the operating fluid container interior 11 are discharged via the filler neck of the filler pipe 12. The remaining structure of the Figure 7 The operating fluid reservoir system 1 shown is identical in structure and functionality to that shown in Figure 6 operating fluid reservoir system shown, so that with regard to the structure and functionality, the explanations with reference to Figure 6 is referred to.

[0107] Figure 8 shows an operating fluid container system 1 according to an eighth embodiment of the present invention. Figure 8 The operating fluid reservoir system 1 shown differs from that shown in Figure 7The operating fluid container system 1 shown differs only in that an electrically actuated refueling vent valve 30 is arranged in the refueling vent line 71. The refueling vent valve 30 is, as already mentioned, connected to the electronic control device for data exchange via a data line (not shown). The remaining structure and functionality of the Figure 8 The operating fluid reservoir system 1 shown is identical in structure and functionality to that shown in Figure 7 operating fluid reservoir system shown.

[0108] In Figure 91 shows an operating fluid container system 1 according to a ninth embodiment of the present invention. In the operating fluid container system 1 according to the ninth embodiment, the operating vent valve and the refueling vent valve are combined to form an operating and / or refueling vent valve 40. The operating and / or refueling vent valve 40 has an operating vent inlet port 41, an operating vent outlet port 42, a refueling vent inlet port 43, and a refueling vent outlet port 44. The operating vent inlet port 41 and the refueling vent inlet port 43 are each fluidly connected to the operating fluid container interior 11.The fluid connection of the operating vent inlet connection 41 to the operating fluid container interior 11 is via the vent line 70, and the fluid connection of the refueling vent inlet connection 43 to the operating fluid container interior 11 is via the refueling vent line 71. The operating vent outlet connection 42 is fluidly connected to the atmosphere via the adsorption filter 80, and the refueling vent outlet connection 44 is fluidly connected to the filler pipe 12.

[0109] The operating and refueling vent valve 40 can be electrically actuated or adjusted between a ventilation position, a refueling position, and a closed position. In the ventilation position, the operating fluid container interior 11 is fluidly connected to the atmosphere and to the filler pipe 12 by means of the operating and refueling vent valve 40. In the refueling position, the operating fluid container interior 11 is fluidly separated from the atmosphere by means of the operating and refueling vent valve 40 and fluidly connected to the filler pipe 12 by means of the operating and refueling vent valve 40. In the closed position of the operating and / or refueling vent valve 40, the operating fluid container interior 11 is fluidly separated from the atmosphere and from the filler pipe 12 by means of the operating and refueling vent valve 40.

[0110] The adjustment of the operating and refueling venting valve 40 between the ventilation position, the refueling position and the closed position is preferably carried out via a slide within the operating and refueling venting valve 40.

[0111] The overpressure protection valve 21 and the vacuum protection valve 22 are arranged in the operating vent line 70 and are each movable between an open position, in which gas exchange through the respective valve is possible, and a closed position, in which gas exchange through the respective valve is prevented. The overpressure protection valve 21 is in its closed position when the internal pressure in the interior 11 of the operating fluid reservoir is less than the maximum pressure. The overpressure protection valve 21 is transferred to its open position when the internal pressure in the interior 11 of the operating fluid reservoir is greater than the maximum pressure. The vacuum protection valve 22 is in its closed position when the internal pressure in the interior 11 of the operating fluid reservoir is greater than the minimum pressure.If the internal pressure in the interior of the operating fluid reservoir 11 is less than the minimum pressure, the vacuum protection valve 22 is moved to its open position.

[0112] The remaining structure and functionality of the operating fluid container system 1 according to the ninth embodiment is identical to the structure and functionality of the operating fluid container system according to the eighth embodiment, so that reference is made to the explanations therein. List of reference symbols

[0113] 1Service fluid reservoir system 10Service fluid reservoir / fuel reservoir / fuel tank 11Service fluid reservoir interior / fuel tank interior 12Filler pipe 13Filler pipe cap 14Fuel filler flap / tank cap 15Pressure sensor / internal pressure sensor 16Ambient pressure sensor / external pressure sensor 17Fill level sensor 20Vent valve / service vent valve 21Overpressure protection valve 22Underpressure protection valve 23Gas flow control element 30Refueling vent valve 40Service and refueling vent valve 41Service vent inlet connection 42Service vent outlet connection 43Refueling vent inlet connection 44Refueling vent outlet connection 50Regeneration valve 60Tank isolation valve 70Vent line / service vent line 71Refueling vent line 72Purge line 80Adsorption filter / activated carbon filter 81Inlet connection (of the adsorption filter) 82Outlet connection (of the adsorption filter) 83Flush connection (of the adsorption filter)。

Claims

1. A method for controlling the internal pressure of an operating liquid container (10) of a motor vehicle, having the following method steps of: - determining (A1) an internal pressure of the operating liquid container (10) by means of a pressure sensor (15) arranged in an operating liquid container interior (11); - determining (A2) an ambient pressure of the operating liquid container (10) by means of an ambient pressure sensor (16); - determining (A3) a differential pressure between the internal pressure and the ambient pressure by means of an electronic control device; - comparing (B3) the differential pressure with a predetermined maximum differential pressure by means of the control device; - comparing (B4) the differential pressure with a predetermined minimum differential pressure by means of the control device; - outputting (C1) an opening signal from the control device to a vent valve (20, 40) that is arranged in a vent line (70) or between the operating liquid container interior (11) and the vent line (70), wherein the vent line (70) fluidically connects the operating liquid container interior (11) to the atmosphere when the determined differential pressure is equal to the maximum differential pressure or above the maximum differential pressure or when the determined differential pressure is equal to the minimum differential pressure or below the minimum differential pressure; and - transferring (D) the vent valve (20, 40) into an open position, in which the operating liquid container interior (11) is fluidically connected to the atmosphere by means of the vent valve (20), when the opening signal is received.

2. The method as claimed in claim 1, characterized in that, in the method step of transferring (D) the vent valve (20, 40) into its open position, the vent valve (20, 40) is transferred gradually into its open position.

3. The method as claimed in one of the preceding claims, characterized by the following features of: - determining (E) whether a regenerating valve (50) arranged in a flushing line (72) or between a flushing connection (83) of an adsorption filter (80) and the flushing line (72) is in an open position, wherein the flushing line (72) fluidically connects an adsorption filter interior to an intake tract of an internal combustion engine of the motor vehicle; - outputting (F) a closing signal from the control device to the vent valve (20, 40) when the regenerating valve (50) is in the open position; and - transferring (G) the vent valve (20) into a closed position, in which the operating liquid container interior (11) is fluidically separated from the atmosphere by means of the vent valve (20), when the closing signal is received.

4. An operating liquid container system (1) having: - at least one operating liquid container (10); - at least one pressure sensor (15), arranged in an operating liquid container interior (11), for determining an internal pressure of the operating liquid container interior (11); - a vent line (70) that fluidically connects the operating liquid container interior (11) to the atmosphere; - an electrically actuable vent valve (20, 40) that is arranged in the vent line (70) or between the operating liquid container interior (11) and the vent line (70) and is actuable between an open position, in which the operating liquid container interior (11) is fluidically connected to the atmosphere, and a closed position, in which the operating liquid container interior (11) is fluidically separated from the atmosphere by means of the vent valve (20); - an electronic control device that is connected to the pressure sensor (15) and the vent valve (20, 40) via a data line; and - an ambient pressure sensor (16) for determining an ambient pressure of the operating liquid container (10), wherein the operating liquid container system (1) is characterized by the following feature: - the electronic control device is configured to carry out a method as claimed in one of the claims 1 and / or 2.

5. The operating liquid container system (1) as claimed in claim 4, characterized by the following features: - the operating liquid container system (1) has an adsorption filter (80) that is fluidically connected to the vent line (70) by means of an inlet connection (81) and to the atmosphere by means of an outlet connection (82); and - the electronic control device is configured to carry out the method as claimed in claim 3.

6. The operating liquid container system (1) as claimed in one of claims 4 to 5, characterized by the following features: - the operating liquid container system (1) has an overpressure protection valve (21) that is arranged in the vent line (70) or between the operating liquid container interior (11) and the vent line (70); - the overpressure protection valve (21) is actuable between an open position, in which gas exchange is allowed by the overpressure protection valve (21), and a closed position, in which gas exchange is prevented by the overpressure protection valve; - the overpressure protection valve (21) is in its closed position when the internal pressure in the operating liquid container interior (11) is below the maximum pressure; and - the overpressure protection valve (21) is transferred into its open position when the internal pressure in the operating liquid container interior (11) is above the maximum pressure.

7. The operating liquid container system (1) as claimed in one of claims 4 to 6, characterized by the following features: - the operating liquid container system (1) has a negative pressure protection valve (22) that is arranged in the vent line (70) or between the operating liquid container interior (11) and the vent line (70); - the negative pressure protection valve (22) is actuable between an open position, in which gas exchange is allowed by the negative pressure protection valve (22), and a closed position, in which gas exchange is prevented by the negative pressure protection valve; - the negative pressure protection valve (22) is in its closed position when the internal pressure in the operating liquid container interior (11) is above the minimum pressure; and - the negative pressure protection valve (22) is transferred into its open position when the internal pressure in the operating liquid container interior (11) is below the minimum pressure.

8. The operating liquid container system (1) as claimed in one of the claims 4 to 7, characterized by the following features: - the operating liquid container system (1) has a filler tube (12) that leads into the operating liquid container interior (11), and a refueling vent line (71) that is fluidically connected to the operating liquid container interior (11) and the filler tube (12); - the electrically actuable vent valve (20, 40) is configured as a service and / or refueling vent valve (40) with a service venting inlet connection (41), a service venting outlet connection (42), a refueling venting inlet connection (43) and a refueling venting outlet connection (44); - the service venting inlet connection (41) and the refueling venting inlet connection (43) are each fluidically connected to the operating liquid container interior (11), the service venting outlet connection (42) is fluidically connected to the atmosphere, and the refueling venting outlet connection (44) is fluidically connected to the filler tube (12); - the service and / or refueling vent valve (40) is electrically actuable between a venting position, a refueling position and a closed position; - in the venting position, the operating liquid container interior (11) is fluidically connected to the atmosphere and to the filler tube (12) by means of the service and / or refueling vent valve (40); - in the refueling position, the operating liquid container interior (11) is fluidically separated from the atmosphere by means of the service and / or refueling vent valve (40) and fluidically connected to the filler tube (12) by means of the service and / or refueling vent valve (40); and - in the closed position, the operating liquid container interior (11) is fluidically separated from the atmosphere and the filler tube (12) by means of the service and / or refueling vent valve (40).