Tank venting valve, tank venting system and method for keeping an electromagnetically actuated valve open

Abstract

Fuel tank venting valve for a motor vehicle for selectively enabling or blocking a fluid flow, comprising: a valve body (10) or plunger that is linearly movable in one direction (R1) and in another direction opposite to the first direction (R2) in order to selectively open or close a valve passage (D), at least one spring (20) for pushing the valve body (10) in one direction (R1), an actuator for moving the valve body (10) in the other opposite direction (R2) against the force applied by the spring (20), and a blocking element (50) for blocking the valve body (10) such that movement of the valve body (10) in one direction (R1) is blocked, wherein the blocking element (50) has an elastically restorable blocking member (52).which in its undeformed state is in the release position and can be moved into the blocked position to block the valve body (10) by elastically restorable deformation.

Description

The present invention relates to a tank venting valve, a tank venting system for a motor vehicle, and a method for keeping open an electromagnetically actuated valve of the normally closed type. In motor vehicles, fuel vapors are retained from the fuel tank by closing a vent line to the atmosphere via a valve when the engine is off. This valve opens only when the engine is running, allowing air to enter the tank as fuel is drawn, thus preventing a vacuum from forming. Additionally, an activated carbon canister is integrated into the vent line to absorb fuel vapors. During engine operation, the activated carbon canister is regenerated by drawing combustion air through the activated carbon filter. Before opening the fuel cap, the vent line must be opened to release any excess pressure in the fuel tank, thus preventing fuel from spraying out of the open cap. Furthermore, the vent line must be opened before refueling so that the displaced air can escape through the vent line, preventing fuel from spraying out of the open cap. For this purpose, an electromagnetically actuated on / off valve is arranged in the vent line, which is normally closed and can be opened by activating an electromagnet. Such valves are disclosed, for example, in DE 10 2010 044 336 A1 and DE 10 2011 114 120 A1. During the assembly line production of motor vehicles, a certain minimum amount of fuel must be added to the fuel tank so that the vehicle can undergo a final inspection and be driven independently after completion. This requires the fuel tank's vent valve to be powered to open the vent line. However, a fully functional electrical control system may not yet be available and ready for use during assembly. Therefore, to open the tank vent valve, a special control unit must be used externally to refuel the still-incomplete vehicle. This procedure is cumbersome and time-consuming, thus delaying the entire assembly line production process. US 2 251 441 A discloses a normally closed solenoid valve with a spring that closes the valve and an electromagnet that opens the valve against the pressure of the spring. DE 100 51 310 A1 discloses an actuator, in particular for valves, relays and the like, which has an electromagnet and a movable magnetic armature. DE 38 14 765 A1 describes a solenoid valve with a permanent magnet, the magnetic force of which is predominantly stored as spring force in the closed position of the valve. DE 196 49 225 A1 describes a valve with a closing element movable back and forth between a first and a second switching position, an electrically controllable actuator to move the closing element against a spring force from the first to the second closing position, and holding means that hold the closing element in the second switching position, wherein the holding means are formed by a piezoelectric bending element that positively locks the closing element in the second switching position. DE 10 2012 207 584 A1 discloses a solenoid valve with a valve stem and an electromagnetic actuator for deflecting the valve stem from a first switching position to a second switching position. The solenoid valve also includes a support device for bracing the valve stem. The support device has a different shape depending on the deflection of the valve stem. The solenoid valve further comprises a locking device configured to move a movable retaining element into a locking position, in which the retaining element rests against the support device, when the electromagnetic actuator is activated to deflect the valve stem into the second switching position, and to remove the retaining element from the locking position when the electromagnetic actuator is deactivated. DE 43 26 838 A1 discloses a bistable electromagnetic switching system with a single magnetic winding and a spring-resettable armature, wherein the armature is mechanically operatively connected to a locking mechanism that can be alternately engaged and disengaged by overtravel, and which, when the locking mechanism is engaged, prevents the armature from returning to its initial position. The armature is preferably designed as a plunger core, and the locking mechanism is preferably of a type known in principle for the feed mechanism of writing styluses. A signaling circuit can be provided to unambiguously assign the switching pulses to the respective switching states. The switching system in question is preferably used in a solenoid valve or a contactor. The object of the invention is therefore to improve a tank venting valve and the corresponding tank venting system in such a way that initial refueling during the assembly line production of a motor vehicle can be simplified and accelerated. This task is solved by the characteristics of independent claims. Beneficial further training is subject to dependent claims. According to a first aspect, a fuel tank venting valve for a motor vehicle is provided for selectively enabling or blocking a fluid flow, comprising: a valve body or plunger that is linearly movable in one direction and in another direction opposite to the first direction in order to selectively open or close a valve passage, at least a spring for pushing the valve body in one direction, an actuator for moving the valve body in the other opposite direction against the force applied by the spring, and a blocking element for blocking the valve body such that movement of the valve body in one direction is blocked, wherein the blocking element has an elastically restorable blocking member which is in the release position in the undeformed state and can be moved into the blocked position to block the valve body by elastically restorable deformation. By blocking the valve body in such a way that it cannot be moved in one direction, the blocking element locks the valve body in an intermediate position between the fully open and fully closed positions. In this way, the valve is open when de-energized, even though it is a valve that is normally closed when de-energized. In this way, a fuel tank can be filled with fuel quickly and easily during the assembly line production of motor vehicles because, in this position of the locking element of a tank venting valve, the fuel tank's vent line is open. An external device for energizing or activating the tank venting valve is not required for this tank venting valve according to the invention. This allows the initial refueling process to be carried out quickly and easily on the assembly line. Preferably, the valve passage is closed by a sealing plate of the valve body bearing against a valve seat when the valve body is moved in one direction by the spring. Preferably, the blocking element is movable between a blocked position for blocking the valve body and a release position for releasing the valve body and engages with the valve body or an element connected to it, such as a magnetic armature or a stop ring, in the blocked position. The blocked position can only be released by opening the valve and thus releasing the blockage. According to the invention, the blocking element has an elastically resettable blocking member which is in the release position in the unloaded or undeformed state and can be moved into the blocked position to block the valve body by elastically resettable deformation. Because the locking element has an elastically resetting locking component that elastically returns to the non-blocking position after the initial actuation of the tank vent valve's electromagnet, the valve can be completely closed after the electromagnet is deactivated. No further step is required to deactivate the locking element. Preferably, the elastically releasable blocking element can be elastically releasable via an inlet or outlet opening of the valve by means of a tool inserted into it. The blocking element only works in the delivered state of the tank venting valve, by deforming the blocking member elastically with a suitable tool so that the blocking member engages with the valve body or an element connected to it, such as a magnetic armature or a stop ring. By energizing the electromagnet, the locking element is released from the valve body, and the fuel tank vent valve is moved to the fully open position. Releasing the locking element from the valve body causes it to elastically return to its unblocked position, allowing the valve body to return to the fully closed position of the fuel tank vent valve after the electromagnet is deactivated. Therefore, after the initial activation of the fuel tank vent valve, the locking element no longer serves any function and does not interfere with its operation during normal vehicle use. Preferably, the elastically restorable state of the blocking element is maintained by the blocking element engaging with the valve body or an element connected to it, such as a magnetic armature or a stop ring. Preferably, the actuator has an electromagnet which, when activated, pulls the valve body in the opposite direction against the spring force. Preferably, the valve is closed in the non-activated state of the actuator by the spring pressing the valve body against the valve seat. According to another aspect, a tank venting system with an atmosphere connection and a tank venting valve, as previously described, is provided. According to a further aspect, a method for keeping an electromagnetically actuated valve of the normally closed type open is provided with the following steps: Opening the valve by activating an actuator of the valve, moving a blocking element or a blocking member connected to the blocking element into a blocking position, deactivating the actuator so that a valve body or an element connected to it, such as a magnetic armature or a stop ring, engages with the blocking element or blocking member in such a way that movement of the valve body into the closed position of the valve is prevented, wherein the blocking element has an elastically restorable blocking member which is in the release position in the undeformed state and can be moved into the blocked position to block the valve body by elastically restorable deformation. The invention will now be explained in more detail using exemplary embodiments with reference to the attached drawings. Fig. 1 shows a section through a tank vent valve according to the invention in the closed position according to a first embodiment of the invention. Fig. 2 shows the tank vent valve from Fig. 1 in the open position, in which flow is permitted. Fig. 3 shows a detail view of Fig. 2 in the area of ​​the valve seat. Fig. 4 shows a view from below of the blocking element in the release position. Fig. 5 shows a sectional view similar to Fig. 1 and Fig. 2, but in the blocking position of the blocking element, in which the valve is partially open and blocked by the blocking element. Fig. 6 shows a detail view of Fig. 5. Fig. 7 shows a view from below of the blocking element in the blocking position. Fig. 8 shows a perspective detail view of the blocking element. Fig. 9 shows a sectional view of a valve according to the invention according to a second embodiment in the closed position.Figure 10 shows a sectional view of the valve from Figure 9 in the open position. Figure 11 shows a detail view of Figure 10. Figure 12 shows a bottom view of the locking element in the release position. Figure 13 shows a sectional view of the valve from Figures 9 and 10 in the blocked position of the locking element, in which the valve is partially open. Figure 14 shows a detail view of Figure 13. Figure 15 shows a bottom view of the locking element in the blocked position. And Fig. 16 shows a perspective detail view of the blocking element of the second embodiment. As shown in the sectional views of Figs. 1 and 2, an electromagnet 30 is housed in a casing 70 of a tank vent valve, which interacts with a magnetic armature 12. In the views of Figs. 1 and 2, the magnetic armature 12 is pressed downwards in direction R1 by a spring 20 to press a sealing plate 14 of the valve against a valve seat 40. In the closed position of the valve shown in Fig. 1, in which the sealing plate 14 is pressed against the valve seat 40, fluid flow through the valve is prevented. However, when the electromagnet 30 is energized, an electromagnetic force is generated that pulls the magnetic armature 12 in Fig. 2 upwards in a different direction R2 against the spring force of the spring 20, so that the sealing plate 14 connected to the magnetic armature 12 lifts off the valve seat 40. In this way, a flow path S, shown in Fig. 2, is opened through the valve from a first valve port 60 to a second valve port 62 via the passage D opened by the sealing plate 14 and the valve seat 40. The one direction R1, in which the spring 20 acts, is opposite to the other direction R2, in which the magnetic armature 12 is moved when the electromagnet 30 is activated. Valves of this type use an actuator with an electromagnet 30 as the actuator to operate the valve. This electromagnet is directly or indirectly connected to the sealing element in the form of the sealing plate 14. When the electromagnet 30 is deactivated, the spring 20 holds the valve closed by pressing the magnetic armature 12 against the valve seat 40. The flow direction of the medium through the valve is usually set such that, when the valve is closed, the differential pressure that builds up between the inlet and outlet of the valve additionally presses the sealing plate 14 against the valve seat 40. Depending on the application, however, the flow direction can also be reversed. To open the valve, the sealing plate 14 must be lifted from the valve seat 40 by the electromagnetic actuator. The actuator must therefore work against the spring 20 and against the differential pressure acting on the sealing plate 14. The minimum force required by the electromagnetic actuator to open the valve depends primarily on the spring force, the valve seat size (area), and the maximum differential pressure when the valve is closed. The magnetic armature 12 is preferably guided axially by a guide pin 16. By deactivating the electromagnet 30, the electromagnetic force is reduced by the reduction of the magnetic field, so that the spring 20 can push the magnetic armature 12 downwards again to return the valve from the open position shown in Fig. 2 to the closed position shown in Fig. 1. Furthermore, a locking element 50 is arranged between the sealing plate 14 and the magnetic armature 12, which has no function in the positions shown in Fig. 1 and Fig. 2 and is explained in more detail below with reference to the further figures, in particular Fig. 4, Fig. 5, Fig. 6 to Fig. 7. The magnetic armature 12, which is movable along its guide pin 16 and has the sealing plate 14 at its lower end, forms a valve body 10 in the valve of Figs. 1 and 2. It is understood that the magnetic armature 12 could also be designed separately from a valve body and could be guided axially in a manner other than by the guide pin 16. As shown in the detailed view of Fig. 3, the magnetic armature 12 further has a groove 12a on a lower end face, with which a locking member 52 of the locking element 50 can engage, as will be explained below. This locking member 52 is, as shown in Fig. 4, arranged at the end of an elastically restoring arm 53 of the locking element 50. The locking element 50 is an essentially circular element that is permanently installed in the valve and remains permanently in the valve even after initial activation, i.e., after fulfilling its function, namely locking in the delivery state. The blocking process by the blocking element 50 is explained in more detail below with reference to Figures 5, 6 to 7. Figure 5, similar to Figures 1 and 2, shows a sectional view of the valve, but in a partially open position, i.e., in an intermediate position between the fully open position of Figure 2 and the fully closed position of Figure 1. This intermediate position shown in Figure 5 is achieved by blocking by the blocking element 50. As shown particularly in the detailed view of Fig. 6, in the blocking position of the blocking element 50, the blocking member 52 is displaced radially inwards such that it blocks or prevents a downward movement of the magnetic armature 12. In this position, the intermediate position of the magnetic armature 12 results on the one hand from the spring force exerted by the spring 20 and on the other hand from the magnetic armature 12 bearing against the blocking element 52. The blocking element 52 thus blocks the magnetic armature 12 in an intermediate position in which the sealing plate 14 is lifted from the valve seat 40. A projection 54 in the form of a protruding nose engages in the groove 12a of the magnetic armature 12. In this way, the locking element 52 is locked to the magnetic armature 12 and can no longer be moved radially outwards. Fig. 7 shows a bottom view of the locking element 52 in the locked position, in which the projection 54 engages in the groove 12a of the magnetic armature 12. In this position, the elastically restoring arm 53 is elastically deflected and would push the locking element 52 radially outwards due to its elastic restoring force. However, this restoring movement of the locking element 52 is prevented by the engagement of the projection 54 with the groove 12a of the magnetic armature 12. Thus, this locked state of the locking element 52 is stable and requires no activation of the electromagnet 30 or any other external energy. This blocked state of the magnetic armature 12 in the intermediate position of the tank vent valve corresponds to the delivery state of the tank vent valve. In this state, the valve is partially open, and the initial refueling of a motor vehicle on the assembly line can be carried out easily without requiring the electromagnet 30 of the tank vent valve to be energized. After completion of the motor vehicle and completion of the corresponding electrical control, the locking element 50 is deactivated upon initial actuation of the electromagnet 30 and corresponding upward movement of the magnetic armature 12. In an activated state of the electromagnet 30 and corresponding upward movement of the magnetic armature 12, the engagement of the projection 54 of the locking element 50 with the groove 12a of the magnetic armature 12 is released, and the elastically restoring arm 53 moves radially outwards, so that the magnetic armature 12 is now freely movable between the closed position of the fuel tank vent valve shown in Fig. 1 and the open position of the fuel tank vent valve shown in Fig. 2. The locking element 50 remains inside the valve in this state and does not need to be removed. After the initial activation of the tank vent valve, the locking element 50 no longer serves any function. It merely serves to hold the tank vent valve open in its factory default state, so that initial refueling can be carried out easily and without supplying power to the electromagnet 30. After the tank vent valve is actuated for the first time by supplying power to the electromagnet 30, the locking position, shown in Figures 6 and 7, is released by the elastically restoring arm 53 pulling the locking element 52 radially outward from its locked position. Fig. 8 shows a perspective detail view of the locking element 50 with the locking member 52, which is arranged at the free end of the elastically restoring arm 53. A projection 54 is arranged on an upper surface of the locking member 52, which can engage with the groove 12a of the magnetic armature. To create the blocked state, the completed tank vent valve is energized, causing it to move into the open position shown in Fig. 2. In this state, the elastically restoring arm 53 is pressed radially inwards into the blocked position via the first valve connection 60 using a tool (not shown). The power supply to the electromagnet 30 is then interrupted, causing the magnetic armature 12 to move downwards and be pressed against the blocking element 52. In this blocked position, the projection 54 engages with the groove 12a of the magnetic armature 12. In this way, the blocked state of the locking element 50 is maintained. The position of the locking element 50 shown in Figs. 6 and 7 is the delivery state of the valve, in which the tank venting valve is installed in the motor vehicle and its tank venting system. In this way, the valve is partially open in the delivery state, so that the initial refueling of the motor vehicle can be carried out easily without having to activate the valve. Figures 9, 10, 11, 12, 13, 14, 15 to 16 show a second embodiment, which is constructed similarly to the first embodiment. Accordingly, the same reference numerals are used for the same elements. Their design and function will not be described in detail here to avoid repetition. Instead, only the differences from the first embodiment will be explained. The magnetic armature 12 of the second embodiment does not have a guide pin 16, but instead a guide bushing 17 on its outer circumference. Fig. 9 shows, corresponding to Fig. 1, the closed state of the tank venting valve, and Fig. 10 shows, corresponding to Fig. 2, the open state of the tank venting valve with the flow path S through the valve. The magnetic armature 12 of the second embodiment, as shown particularly in the detailed view of Fig. 11, does not have a groove 12a, but rather a stop ring 18 with a groove 18a. The stop ring 18 is axially fixed on the outer circumference of the magnetic armature 12 and positions the sealing plate 14. The groove 18a of the stop ring 18 serves as an element for engaging with the projection 54 of the locking element 50. Fig. 12 shows a bottom view of the locking element 50 in the release position, in which movement of the magnetic armature 12 is permitted. This position of the locking element 50 in Fig. 12 corresponds to the release position of the locking element 50 of the first embodiment shown in Fig. 4. Fig. 13 shows, analogous to Fig. 5 of the first embodiment, a sectional view of the valve, but in a partially open position, i.e., in an intermediate position between the fully open position of Fig. 10 and the fully closed position of Fig. 9. This intermediate position shown in Fig. 13 is achieved by blocking it with the blocking element 50. In particular, the detailed view of Fig. 14 shows the engagement between the projection 54 of the locking member 52 and the groove 18a of the stop ring 18. Fig. 15 shows a view from below in the blocked position of the locking element 50 according to Fig. 7 of the first embodiment, and Fig. 16 shows a detailed view of the locking element 50 of the second embodiment. This blocking element 50 of the second embodiment is designed similarly to the blocking element 50 of the first embodiment and also has a blocking member 52, which is attached to the free end of an elastically restoring arm 53. The blocking element 50 is also circular and remains in the valve after initial activation of the tank venting valve and does not need to be removed. It is understood that the invention is not limited to solenoid valves, but that other types of actuators, such as pneumatic or hydraulic actuators, can be used. The tank venting valve can also be installed in a motor vehicle at locations other than a tank venting system, where it is important that the valve is open when de-energized in the delivery state and closed when de-energized after initial activation in the operating state. The blocking element is preferably made of an elastic plastic, such as polyethylene (PE), polyamide (PA), PVC, etc. Although the tank venting valve described here is a directly controlled valve in which the actuator directly lifts the sealing plate 14 via the force of the electromagnet 30, a pilot-controlled valve can also be used in which a pilot valve is first opened to reduce the differential pressure at the main valve and to facilitate its opening. Reference symbol list 10 Valve body 12 Magnetic armature 12a Groove 14 Sealing plate 16 Guide pin 17 Guide bushing 18 Stop ring 18a Groove 20 Spring 30 Electromagnet 40 Valve seat 50 Locking element 52 Locking link 53 Elastically restoring arm 54 Projection 60 First valve port 62 Second valve port 70 Housing D Valve passage R1 one direction R2 other direction S Flow path

Claims

Fuel tank venting valve for a motor vehicle for selectively enabling or blocking a fluid flow, comprising: a valve body (10) or plunger that is linearly movable in one direction (R1) and in another direction opposite to the first direction (R2) in order to selectively open or close a valve passage (D), at least one spring (20) for pushing the valve body (10) in one direction (R1), an actuator for moving the valve body (10) in the other opposite direction (R2) against the force applied by the spring (20), and a blocking element (50) for blocking the valve body (10) such that movement of the valve body (10) in one direction (R1) is blocked, wherein the blocking element (50) has an elastically restorable blocking member (52).which in its undeformed state is in the release position and can be moved into the blocked position to block the valve body (10) by elastically restorable deformation. Tank venting valve according to claim 1, wherein the valve passage (D) is closed by a sealing plate (14) of the valve body (10) bearing against a valve seat (40) when the valve body (10) is moved in one direction (R1) by the spring (20). Tank venting valve according to claim 1 or 2, wherein the blocking element (50) is movable between a blocked position for blocking the valve body (10) and a release position for releasing the valve body (10) and engages with the valve body (10) or an element connected thereto in the blocked position. Tank venting valve according to one of the preceding claims, wherein the elastically restorable blocking element (52) can be elastically restorable via a first valve port (60) and / or an inlet opening and / or an outlet opening of the valve by means of a tool inserted therein. Tank venting valve according to one of the preceding claims, wherein the elastically restorable state of the blocking element (52) is maintained by the blocking element (52) engaging with the valve body (10) or an element connected thereto. Tank venting valve according to claim 3 or 5, wherein the element connected to the valve body (10) is a magnetic armature (12) or a stop ring (18). Tank venting valve according to one of the preceding claims, wherein the actuator has an electromagnet (30) which, when activated, pulls the valve body (10) against the spring force in the other direction (R2). Tank venting valve according to one of the preceding claims, wherein the valve is closed in the non-activated state of the actuator by the spring (20) pressing the valve body (10) against the valve seat (40). Tank venting system with an atmospheric connection and a tank venting valve according to one of the preceding claims. Method for keeping open an electromagnetically actuated valve of the normally closed type comprising the steps: opening the valve by activating an actuator of the valve, moving a blocking element (50) or a blocking member (52) connected to the blocking element (50) into a blocking position, deactivating the actuator, so that a valve body (10) or an element connected to it engages with the blocking element (50) or the blocking member (52) in such a way that movement of the valve body (10) into the closed position of the valve is prevented, wherein the blocking element (50) has an elastically restorable blocking member (52) which is in the release position in the undeformed state and can be moved into the blocked position to block the valve body (10) by elastically restorable deformation.

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