Tank system with a valve to ensure rapid initial filling with an operating medium

Abstract

Tank system for storing an operating medium, in particular fuel, water or an aqueous urea solution, with a valve (1) for ensuring rapid initial filling of the tank system with the operating medium, comprising a movable valve closing element (5) which is acted upon by the spring force of a spring in the direction of a valve seat (6), wherein the valve (1) further comprises a spacer (8) by means of which the valve (1) can be held temporarily open, wherein the spacer (8) is made of a material which dissolves upon contact with the operating medium, wherein the valve is arranged in a vent line (18) of the tank system, wherein the vent line (18) is formed in a vent nozzle (19) which is covered by a cap (20), characterized in that the cap (20) has spring arms (21) forming the spring.by means of which the valve closing element (5) is axially preloaded in the direction of the valve seat (6).

Description

[0001] The invention relates to a tank system with a valve for the rapid initial filling of the tank system with an operating medium, for example fuel, water or an aqueous urea solution, with the features of the preamble of claim 1. State of the art

[0002] Due to steadily increasing legal requirements for the emission levels of internal combustion engines, exhaust gases undergo aftertreatment to comply with the prescribed limits. To reduce nitrogen oxide emissions, particularly in diesel engines, reduction catalysts are used, which significantly lower NOx emissions. Before the exhaust gases enter the catalyst, they are treated with a reducing agent, such as an aqueous urea solution, which causes the formation of ammonia. This ammonia then reacts with the nitrogen oxides in the downstream catalyst to form harmless nitrogen and water. The aqueous urea solution is supplied via metering systems, which typically include a reservoir for storing the reducing agent, a metering module for adding the reducing agent, and a conveying module for transporting the reducing agent from the reservoir to the metering module.

[0003] A dosing system of the aforementioned type is described, for example, in DE 10 2004 054 238 A1. To prevent the aqueous urea solution from freezing at low ambient temperatures and thus potentially damaging the dosing system, this document proposes emptying at least one liquid-filled area between a dosing point and a storage tank in the opposite direction to the normal operating flow direction of the liquid. For this purpose, the dosing system preferably includes a feed pump with a reversible direction of rotation. Alternatively, reversing the flow direction by using suitable valves, for example, a 4 / 2-way valve, is proposed. A 4 / 2-way valve is permeable in one or the other flow direction depending on the valve position.

[0004] To effectively prevent refilling of emptied sections of the system during extended periods of vehicle inactivity, dosing systems are known from the prior art that incorporate a flood protection function, which can be implemented, for example, via passive spring-loaded valves. The valve springs must be designed such that, on the one hand, they ensure flood protection after emptying, and on the other hand, they allow for pumping and return pumping.

[0005] However, such passive spring-loaded valves have a negative impact on the initial filling time of the dosing system in the factory, as the conveying module has to generate a higher pressure or vacuum to open the valve.

[0006] A non-return valve for a domestic hot water circulation system is known from DE 43 39 617 A1.

[0007] DE 195 47 493 C1 describes a method for the initial filling of a fluid circuit.

[0008] From DE 10 2005 035 532 A1 a device for the initial filling of a fluid circuit is known.

[0009] Based on the prior art described above, the invention aims to simplify or accelerate the initial filling of a tank system with an operating medium.

[0010] To solve the aforementioned problems, the tank system with the features of claim 1 is proposed. Advantageous embodiments of the invention can be found in the respective dependent claims. Disclosure of the invention

[0011] The proposed tank system, designed to ensure rapid initial filling of a tank system with a working medium, comprises a valve with a movable valve closing element that is acted upon by the spring force of a spring in the direction of a valve seat. The valve further includes a spacer by means of which the valve is temporarily held open, the spacer being made of a material that dissolves upon contact with the working medium. While the spacer temporarily holds the valve open, the initial filling of the system can be carried out easily. Once the system is put into operation after the initial filling, the spacer dissolves, allowing the valve to close.

[0012] In a tank system for storing a working medium, in particular fuel, water, or an aqueous urea solution, the valve is located in a vent line of the tank system. The vent line is further formed into a vent nozzle, which is covered by a cap. The cap is designed to allow air to escape from the vent nozzle.

[0013] According to the invention, the sealing cap has spring arms by means of which the valve closing element of the valve can be axially preloaded in the direction of the valve seat. The axial preload of the valve closing element ensures that the valve closes permanently after the spacer element is released, i.e., after the initial filling of the tank system.

[0014] In a metering system for injecting a reducing agent into the exhaust system of an internal combustion engine, the initial filling time—with the valve open—is approximately 20 to 60 seconds. However, depending on the specific application of the metering or tank system and / or the tank size, the initial filling time can be significantly longer. For example, initial filling times of 160 to 240 seconds are possible. The spacer should be made of a material and / or dimensioned to ensure that it does not dissolve due to contact with the operating medium before the initial filling process is complete. If the valve is designed to provide flood protection within a metering system, the time of completion of the initial filling and the time of the first system drain define a time window for the spacer's dissolution process.

[0015] Preferably, the spacer is a compressed body made from at least one soluble component, such as urea (CO(NH₂)₂) or polyethylene glycol (C₂H₄O). A compressed body made from urea, for example, is capable of dissolving completely in an aqueous urea solution. This ensures that no residues remain that could impair the functionality of the system, in particular the components arranged therein. When the spacer dissolves, no quantities of particles may be released that could damage the system components. Furthermore, it must be ensured that the products dissolving do not affect any components downstream of the system. In the case of a metering system, such components could, for example, include a catalyst arranged in the exhaust system.

[0016] It is further proposed that, in addition to the at least one soluble component, the pressed body also contains at least one excipient, preferably sodium bicarbonate (NaHCO3). The addition of sodium bicarbonate can accelerate the dissolving process. Furthermore, other excipients can be added.

[0017] The spacer is preferably disc-, ring-, or sleeve-shaped. The central recess serves as a flow-through opening for the operating medium and / or air. Furthermore, the spacer preferably surrounds the valve closing element, at least partially. This allows for at least temporary fixation of the spacer in position.

[0018] Furthermore, it is proposed that the spacer be supported axially on the valve closing element and / or on a valve body. For example, the spacer can be inserted between the valve closing element and the valve body. In this case, the valve body serves as a support. The valve seat can also be formed within the valve body.

[0019] Alternatively, the spacer can be inserted between the valve closing element and the valve seat. The spacer thus prevents the spring-loaded valve closing element from returning to the valve seat.

[0020] According to a first preferred embodiment of the invention, the valve seat is designed as a flat seat. Alternatively or additionally, it is proposed that the valve seat interacts sealingly with a valve disc of the valve closing element. These measures, alone or in combination, result in a valve that is simple and inexpensive to manufacture.

[0021] According to a further preferred embodiment of the invention, the valve seat is conically shaped and interacts with a spherical valve closing element. In this embodiment as well, the valve is simple and inexpensive to manufacture. In particular, the valve seat can be formed by a conically extending shoulder in a pipe in which the valve closing element is movably received. This further simplifies the design of the valve.

[0022] Preferred embodiments of the invention are described in more detail below with reference to the accompanying drawings. The figures show: Fig. 1. A schematic longitudinal section through a valve a) before the spacer is removed and b) after the spacer is removed, Fig. 2 a schematic representation of a dosing system known from the prior art, Fig. 3 a schematic representation of a metering system arranged on an exhaust system of a motor vehicle, known from the prior art, Fig. 4 a schematic longitudinal section through a valve according to the invention a) before the spacer dissolves and b) after the spacer dissolves and Fig. 5 a schematic longitudinal section through a tank system with a valve according to the Fig. 4. Detailed description of the drawings

[0023] The one in Fig. 1a and Fig. The valve 1 shown in Figure 1b is part of a storage container 11 for storing an aqueous urea solution as a reducing agent. It comprises a valve body 9, which also serves as the valve housing and forms a valve seat 6, which in this case is designed as a flat seat. A movable valve closing element 5 with a valve disc 10 is received in the valve body 9, and the valve disc 10 seals against the flat seat 6. A piston-shaped section of the valve closing element 5 is attached to the valve disc 10, extends through the valve body 9, and terminates in a plate-shaped section 14. An annular spacer 8 is inserted between the plate-shaped section 14 and the valve body 9, which holds the valve 1 open against the spring force of a spring 7.The spacer 8 prevents the spring force of the spring 7, which is supported on one side by the valve body 9 and on the other side by the valve plate 10 of the valve closing element 5, from pressing the valve closing element 5 into the valve seat 6 (see . Fig. 1a).

[0024] Since the spacer 8 is only intended to hold the valve 1 open temporarily, preferably during the initial filling of a dosing system 3 comprising the reservoir 11 or the valve 1, the spacer 8 is made of a material that dissolves completely in aqueous urea solution. In this case, urea was chosen as the material, as it dissolves upon contact with the aqueous urea solution.

[0025] During the initial filling of a dosing system 3, the reservoir 11 is also filled with reducing agent. In this way, the urea-based spacer 8 comes into contact with the aqueous urea solution and subsequently dissolves (see figure). Fig. 1b) Upon release of the spacer 8, the valve closing element 5 is pressed into the valve seat 6 by the spring force of the spring 7, and the valve 1 closes. The valve 1 is therefore only able to fulfill its function, which may consist, for example, of ensuring flood protection, after the spacer 8 has released.

[0026] In the Fig. Figure 2 is a simplified representation of a known dosing system 3. The dosing system 3 comprises a reservoir 11 for a reducing agent and a pumping module 12, which are connected via lines 2. The pumping module 12 draws reducing agent from the reservoir 11 via the left line 2, while the right line 2 serves to return reducing agent to the reservoir 11, for example, when emptying the system to prevent damage from ice pressure. A check valve is arranged in each of the two lines 2 to prevent backflow of reducing agent in the opposite direction. The valve in the right line 2 thus provides flood protection. To facilitate initial filling of such a system, the valve in the right line 2 is advantageously designed as valve 1 according to Figure 2. Fig. 1a or Fig. 1b trained.

[0027] Fig. Figure 3 shows another known metering system 3 in conjunction with an exhaust system 4 of a motor vehicle. A valve 1 according to the invention can also be used in this system. For this purpose, the valve 1 can be integrated into the reservoir 11, into the line 2, or into a conveying module 12 (not shown). The metering system 3 of the Fig. 3 comprises, in addition to a storage container 11, a conveying module 12, and a line 2, a metering module 13, by means of which the reducing agent can be precisely metered into the exhaust system 4 of the motor vehicle. Furthermore, a control unit 15 is provided for controlling the metering system 3.

[0028] In the exhaust stream 4, a particulate filter 16 is arranged upstream of the metering module 13 of the metering system 3, relative to the direction of exhaust gas flow. Downstream of the metering module 13, an SCR catalyst 17 is located for carrying out selective catalytic reduction, i.e., for reducing the nitrogen oxides in the exhaust gas, with the aqueous urea solution serving as the reducing agent.

[0029] The Fig. 4a and Fig. Figure 4b shows an embodiment of a valve 1 according to the invention. The valve 1 is arranged at the end of a vent line 18 in a vent nozzle 19, onto which a sealing cap 20 is pressed. The sealing cap 20 forms spring arms 21 on its end face, which exert a preload force on a spherical valve closing element 5 in the direction of a conical valve seat 6 (see Figure 4b). Fig. 4a). An annular spacer 8 is inserted between the valve closing element 5 and the valve seat 6. This spacer dissolves completely in the environment of a specific operating medium. When the spacer 8 dissolves, the spring arms 21 of the sealing cap 20 press the valve closing element 5 into the valve seat 6, and the valve closes permanently (see Fig. 4b).

[0030] The in the Fig. 4a and Fig. The valve shown in 4b can, for example, be used in a tank system according to the Fig. 5. During filling of the tank system, the operating medium must pass through at least one filter fabric 22 of an upstream filter, which generally impairs the filling process. In this case, the filter has two filter fabrics 22 connected in series, enclosing an intermediate space. For venting the intermediate space, a venting nozzle 19 with a valve 1 according to the invention is provided, which, according to the Fig. 4a and Fig. 4b is trained.

Claims

[1] Tank system for storing an operating medium, in particular fuel, water or an aqueous urea solution, comprising a valve (1) for ensuring rapid initial filling of the tank system with the operating medium, comprising a movable valve closing element (5) which is acted upon by the spring force of a spring in the direction of a valve seat (6), wherein the valve (1) further comprises a spacer (8) by means of which the valve (1) can be temporarily held open, wherein the spacer (8) is made of a material which dissolves upon contact with the operating medium, wherein the valve is arranged in a vent line (18) of the tank system, wherein the vent line (18) is formed in a vent nozzle (19) which is covered by a cap (20), characterized by, that the closure cap (20) has spring-forming spring arms (21) by means of which the valve closing element (5) is axially pre-tensioned in the direction of the valve seat (6). [2] Tank system according to claim 1, characterized by , that the spacer (8) is a pressed body made from at least one soluble component, such as urea or polyethylene glycol. [3] Tank system according to claim 2, characterized by , that the pressed body contains, in addition to at least one soluble component, at least one auxiliary substance, preferably sodium bicarbonate. [4] Tank system according to one of the preceding claims, characterized by , that the spacer (8) is designed in the shape of a disc, ring or sleeve and preferably surrounds the valve closing element (5) at least partially. [5] Tank system according to any one of claims 1 to 4, characterized by, that the spacer (8) is inserted between the valve closing element (5) and the valve seat (6). [6] Tank system according to any one of claims 1 to 5, characterized by , that the valve seat (6) is conical in shape and interacts with a spherical valve closing element (5).

Images