Fuel system, component, in particular pressure regulator or fuel distribution device, and connection for fuel systems, in particular for hydrogen
Patent Information
- Application Number
- DE102023209783
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-10-06
- Publication Date
- 2025-04-10
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Prior ArtThe invention relates to a fuel system for gaseous fuels, in particular hydrogen, and / or liquid fuels, in particular petrol. More particularly, the invention relates to the field of fuel systems for motor vehicles.DE 10 2006 040 236 A1 discloses a fuel plant for compressed gaseous fuel, in particular natural gas or hydrogen, for an internal combustion engine. The known fuel system has a common rail and a pump. Further provided are a tank for compressed gaseous fuel, in particular natural gas or hydrogen, and an upstream pressure regulator where the pressure is reduced from the tank pressure, which may range to near 5000 psi (34 MPa) or more, to a first reduced pressure of about 400 psi (2.8 MPa). Once the fuel exits the upstream pressure regulator, it moves to a downstream pressure regulator where the fuel is lowered to about 200 psi (1.4 MPa). The fuel then moves to a control regulator. An electronic control unit operates the control regulator such that the fuel is lowered at the second working pressure, in this case approximately 200 psi, to a variable control pressure arranged by the electronic control unit. The fuel supply via common rail nozzles can thereby be increased or decreased.The fuel system known from DE 10 2006 040 236 A1 has the disadvantage that high production costs are produced, so that operation with compressed hydrogen is possible. In particular, the material from which the individual components, in particular the pressure regulators, are produced must be selected such that all existing requirements can be fulfilled. The selection of material is based on the highest requirement, although these can be very different in individual sub-regions of the fuel system.At the same time, selected manufacturing methods for the components, such as casting or forging, and joining methods for joining individual components or individual components, such as brazing, welding or screwing, affect the selection of suitable materials. This limits the use of specific materials and the use of specific methods for producing the components and components.In fuel injection systems for gaseous fuels, special requirements are also placed. As a result, measures which are used in fuel systems for liquid fuels can be disadvantageous in applications for gaseous fuels. Further, hydrogen is more volatile than natural gas. In a fuel injection system for hydrogen, for example, a specification regarding the permissible amount of escaping hydrogen may have to be maintained. This can be particularly in view of the fact that the ignition of escaping hydrogen is prevented.In a fuel injection system for hydrogen, the quantity and thus the pressure of the hydrogen in a connected rail can be regulated via a pressure regulator. For the connections between the tank and the rail, lines can be used which are fastened to screw-in connectors which are in turn screwed into housings. Such screw-in connectors can likewise be provided on the rail.A seal must be ensured between such components, in particular a housing and a screw-in connection piece. In principle, a seal can be realized by a bite edge on one of the components, which ensures a metallic seal of the interface. An O-ring can additionally be used as an additional safety device. In principle, a pure seal can also be realized via an O-ring or a flat seal in the thread base of the screw-in connection piece, in particular a double connection piece.However, special problems arise in the field of use of the fuel injection systems for hydrogen. With a bite edge seal or a seal by means of an O-ring or flat seal (flat sealing ring), it is only possible to seal. In practice, however, strong vibrations can arise during operation or on the vehicle, which can lead to loosening and possibly even to unscrewing of screw connections. Thus, leaks can occur at the fuel injection system, which lead to the escape of hydrogen.In practice, in the event of repair, screwing on and closing the connection between a pressure regulator and a rail may be necessary. Such screwing on and closing can also occur repeatedly in this case. For example, this can relate to the detachable connection between a double connector of the pressure regulator and a line. Then, when unscrewing or screwing the line onto the double connector, the further screw connection, namely between the double connector and the housing of the pressure regulator, can also be adjusted earlier or later. Loosening or undesired stronger tightening can lead to leaks and / or damage to the sealing elements, such as an O-ring or a flat gasket, which can also lead to a system leak with the escape of hydrogen. A bite edge can additionally, i.e. be pressed too strongly, into the sealing surface, so that leaks occur, or the bite edge is released or is released again after an excessively strong pressing, which likewise leads to leaks.Disclosure of the InventionThe connection according to the invention having the features of claim 1, the component according to the invention having the features of claim 9 and the fuel system according to the invention having the features of claim 10 have the advantage that an improved configuration and mode of operation are made possible. In particular, a material selection according to requirements can be made possible and / or leaks or the escape of gaseous fuel and / or the penetration of liquids, in particular water, at the connection can be avoided. This applies in particular with respect to applications for blowing in hydrogen or for pairings of different materials.The measures set out in the dependent claims allow advantageous developments of the method specified in claim 1, of the component specified in claim 9 and of the fuel system specified in claim 10.The microencapsulation makes possible particularly advantageous handling. When the threads are screwed together, the microcapsules are broken up, so that, supported by the screwing-in process, homogeneous mixing of the components can occur. Furthermore, in contrast to a conventional configuration of a 2-component adhesive, the mixing, for example the mixing of the microcapsules and the component surrounding the microcapsules, is not impaired by chemical reactions already taking place. Furthermore, after the application of the microencapsulated adhesive, more time can elapse before the components to be joined are brought together, since the chemical reaction only begins after the microcapsules have broken up.It is advantageous that the microencapsulated adhesive has at least two components, at least one component of the adhesive being enclosed in microcapsules which are surrounded by another component of the adhesive. This provides an advantageous configuration of the adhesive. In particular, if necessary, mixing of the components required as a 2-component adhesive at least immediately before the application can be avoided in a conventional embodiment.It is advantageous that at least between two and three thread turns of the thread of the connector are provided at least substantially continuously with the adhesive which is microencapsulated before screwing, and / or that at least between two and three thread turns of the thread of the first component are provided at least substantially continuously with the adhesive which is microencapsulated before screwing.It is advantageous that the socket is screwed with its thread into the thread of the first component in such a way that a non-rotation device is formed by the adhesive that is microencapsulated before the screwing. As a result, for example, when a connection is screwed on and off repeatedly on a further thread of the connecting piece, which can be designed as a double connecting piece for this purpose, it can be prevented that the connecting piece rotates relative to the first component.It is advantageous that the socket is screwed with its thread into the thread of the first component in such a way that a watertight connection is formed by the adhesive that is microencapsulated before the screwing. This ensures a seal, if necessary, in addition to the anti-rotation device.It is advantageous that at least one sealing element, in particular a sealing ring and / or a flat seal, is provided, by means of which a seal is formed between the first component and the second component. As a result, in particular in the event of a deterioration of the sealing effect of the adhesive caused by aging, reliable sealing can still be ensured.It is advantageous that at least one bite edge is provided, by means of which a seal is formed between the first component and the second component. As a result, in particular in the event of a deterioration of the sealing effect of the adhesive caused by aging, reliable sealing can still be ensured.It is advantageous that the first component and the second component are formed from different materials, in particular a steel and an aluminum. Advantageous material combinations can thereby be realized. A seal can be ensured by the adhesive. In addition, a sealing element can ensure a reliable seal. As a result, corrosion processes between, for example, aluminum and steel can be prevented. In particular, the penetration of water, in particular salt water, is prevented.It is advantageous that the second component has a further connecting piece which has an external thread, and that the further connecting piece serves for a releasable screw connection provided on the external thread of the further connecting piece. In this way, in particular a line can be connected. The releasable screw connection can be designed, for example, for a 25 times loosening and re-tightening. The friction welded connection ensures the tightness of the connection between the first component and the second component, for example a housing and a screw-in connection piece, in particular a double connection piece.Depending on the configuration, at least one of the following features and / or advantages can be realized.In addition to the purpose of sealing, a non-rotational locking can also be achieved by adhering the screw socket by means of microencapsulated adhesive, preferably on the thread of the screw socket.A fast and uncomplicated assembly can be made possible. Sealing of the interface can be made possible. A non-rotational locking of the connecting piece can be realized. If necessary, complicated and expensive geometries, such as a bite edge, can be dispensed with. Damage to sealing elements, such as O-rings and gaskets, during assembly is prevented. A cost-effective implementation is possible since high-quality surfaces, such as in an O-ring application, on the sealing surfaces can be dispensed with.A screw-in connection can be screwed into the provided thread on the housing. In this case, sealing can also be effected by the geometric use of a bite edge or by structural sealing elements, such as O-rings or flat seals. If the seal provided by the adhesive would decrease due to aging of the adhesive, then a reliable seal can still be ensured. This results in increased safety with respect to the sealing.The screw-in connectors can be provided, for example, with a microencapsulated adhesive substance on the thread. In a preferred embodiment, the microencapsulated adhesive is based on the principle of a two-component adhesive, an essential property being that the second component is present in small microcapsules.As a result of the assembly process and the forces which arise when the stubs are tightened, the microcapsules burst open and the two components are connected. The bonding of the two substances produces a chemical reaction and the adhesive mixture hardens. This can provide good tightness on the one hand and anti-rotation protection on the other hand.In addition, for additional safety, a combination with a bite edge geometry or comparable metallic sealing geometries on the screw-in connection piece can also be realized. This can be realized on a double connector.The proposed connection is especially suitable for hydrogen pressure regulators and hydrogen rails and comparable products with seals via screw-in connectors, in particular double connectors.An advantageous sealing of the interface can take place. A free rotation prevention of the connecting piece during operation and service can be achieved. Damage to sealing elements in the event of service is prevented.A connection between different materials is possible, such as aluminum and steel. Corrosion of the aluminum can then be effectively prevented. A fast and safe process can be realized. A configuration of the connection can be achieved which is secure against unscrewing during a service.Brief Description of the DrawingsPreferred exemplary embodiments of the invention are explained in more detail in the following description with reference to the attached drawings, in which corresponding elements are provided with corresponding reference numerals. The following are shown: FIG. 1 shows a fuel system designed as a fuel injection system with a fuel distributor for injecting gaseous fuels, in particular hydrogen, into combustion chambers of an internal combustion engine in a partial schematic illustration corresponding to a possible embodiment of the invention; FIG. 2 shows a connection between a first component and a second component of the fuel injection system shown in FIG. 1 in a partial schematic illustration corresponding to a first exemplary embodiment of the invention; FIG. 3 shows the detail of the connection denoted by III in FIG. 2 in a schematic illustration, wherein a further detail for illustrating thread turns and a possible embodiment of the microencapsulated adhesive is illustrated schematically and greatly simplified; and FIG. 4 shows the first component shown in FIG. 2 and the second component and its connecting piece in a pull-out schematic illustration corresponding to a second exemplary embodiment.Embodiments of the InventionFIG. 1 shows a fuel system 10, designed as a fuel injection system 10, for injecting gaseous fuels, in particular hydrogen, into combustion chambers 11 of an internal combustion engine in a partial schematic illustration corresponding to a possible embodiment of the invention. However, the fuel injection system 10 can also serve for other gaseous fuels, in particular for natural gas.In a modified embodiment, the fuel system 10 can also be designed as a fuel injection system 10 for injecting gaseous and / or liquid fuels. Specifically, such a fuel injection system 10 may also be used for injecting gasoline.The hydrogen is stored in liquid form under high pressure, for example about 700 bar (70 MPa), in a tank-like fuel storage 12. This can be filled via a filling connection 14. Furthermore, an integrated unit 16 comprising a tank valve for filling and discharging hydrogen into or from the fuel accumulator 12 and a temperature sensor for detecting the temperature of the gaseous hydrogen coming from the fuel accumulator 12 is arranged on the fuel accumulator 12.The gaseous hydrogen passes via a pressure line 18 first to a filter 20 and from there further to a high-pressure pressure pressure regulating device (high-pressure pressure regulator) 22, which reduces the pressure of the gaseous hydrogen, for example, to a pressure in the range of 40 bar (4 MPa). The pressure line 18 leads from the high-pressure pressure regulating device 22 further to a pressure sensor 24, a further filter 26 and an optional temperature regulating device 28 finally to a low-pressure pressure regulating unit (LP pressure regulator) 30.The low-pressure pressure regulating unit 30 comprises in the present case, by way of example, two hydraulically parallel pressure regulating valves 32, a low-pressure pressure sensor 34 and a safety valve in the form of a shut-off valve device 36. The pressure in the pressure line 18 is once again lowered by the low-pressure pressure regulating unit 30 from the pressure, which is exemplary at the input side, of approximately 40 bar (4 MPa) to a pressure, for example of approximately 15 bar (1.5 MPa).Downstream of the low-pressure pressure regulating unit 30, the pressure line 18 leads to a fuel distribution device 38, in particular a rail 38, which can be designed, for example, as an elongate tube in the manner of a typical fuel rail, as is known from petrol and diesel fuel systems. The gas pressure prevailing in the fuel distribution device 38 is detected by a pressure sensor 40.A plurality of injectors 42 are connected to the fuel distribution device 38 and direct blow the gaseous hydrogen into the combustion chambers 11 of the internal combustion engine. The gaseous hydrogen is mixed with atmospheric oxygen in the combustion chambers 11 and this mixture is ignited by a respective ignition device 46. Typically, the internal combustion engine is a 2-stroke or 4-stroke piston internal combustion engine of a widely customary design. For example, such an internal combustion engine is used to drive a motor vehicle. However, it can also be used, for example, in a stationary manner for driving a generator for power generation.The fuel supply system 10 and its components are controlled by an electronic control and regulating device 48 which has one or more corresponding microprocessors, a memory for program code, etc. The control and regulating device 48 receives signals from, among other things, the temperature sensor (installed in the integrated unit 16), the pressure sensor 24, the pressure sensor 34, the pressure sensor 40, etc. The control and regulating device 48 controls various components of the fuel supply system 10, among other things, the low-pressure pressure pressure regulating device 30, the safety valve 36 and the ignition devices 46. Furthermore, a control device 50 is also controlled by the control and regulating device 48, which in turn specifically controls or regulates the operation of the fuel accumulator 12.FIG. 2 shows a connection 60 between a first component 61 and a second component 62 of the fuel injection system 10 shown in FIG. 1 in a pull-out schematic illustration corresponding to a first exemplary embodiment of the invention, wherein a situation before screwing together is shown. The connection 60 can be realized at several points 65 in the fuel injection system 10, which serves for injecting gaseous fuels, in particular hydrogen, into combustion chambers 11 of the internal combustion engine.For the purpose of illustration, a first component 61 of the fuel injection system 10 and a second component 62 of the fuel injection system 10 are considered to explain the connection 60. The first component 61 has a bore 63. The second component 62 has a connecting piece 64 which, in the connected state, is inserted into the bore 62 of the first component 61. In this case, the second component 62 is connected at its connection piece 64 to the first component 61 by a microencapsulated adhesive 70.FIG. 3 shows the detail of the connection 60 denoted by III in FIG. 2 in a schematic illustration, wherein a further detail 71 for illustrating thread turns 72 of the connection piece 64 and a possible embodiment of the microencapsulated adhesive 70 is illustrated in a schematic and greatly simplified manner.The connecting piece 64 of the second component 62 has a thread 75 to which the microencapsulated adhesive 70 is applied in this exemplary embodiment before screwing together. The first component 61 has a thread 76. To connect the components 61, 62, the socket 64 is screwed with its thread 75 into the thread 76 of the first component 61.Since the thread 75 of the connector 64 is provided at least partially with the microencapsulated adhesive 70 before screwing, the screw connection is supplemented by a cohesive connection by means of the microencapsulated adhesive 70.In a modified embodiment, the thread 76 of the first component 61 can additionally or alternatively also be provided at least partially with the microencapsulated adhesive 70 before screwing together.As shown in detail 71, the microencapsulated adhesive 70 in this exemplary embodiment has two components 78, 79. Component 78 of adhesive 70 is encapsulated in microcapsules 80. The microcapsules 80 are surrounded by the other component 79 of the adhesive 70.Preferably, at least between two and three threads 72 of the thread 75 of the connector 64 are provided continuously with the microencapsulated adhesive 70. This ensures that a reliable seal is achieved in the screwed-together state. In particular, the penetration of water can then be prevented.In a modified embodiment, at least between two and three thread turns 73 of the thread 76 of the first component 61 are continuously provided with the adhesive 70 which is microencapsulated before screwing.More threads 72, 73 may also be provided with the microencapsulated adhesive 70. In particular, a portion 81 of the neck 64 that extends over a plurality of threads 72 may be provided with the microencapsulated adhesive 70. Accordingly, a portion 84 of the bore 63 may be provided with the microencapsulated adhesive.The mixing and curing of the microencapsulated adhesive take place during or after screwing in. In this case, the microcapsules 80 break open or burst because of the mechanical load which acts on the microcapsules 80 during screwing in, and the two components 78, 79 of the adhesive 70 then mix, so that the chemical curing process is started.When the socket 64 is screwed with its thread 75 into the thread 76 of the first component 61, then a non-rotational locking is formed by the microencapsulated adhesive 70. Further, a waterproof bond is formed by the microencapsulated adhesive 70.The second component 62 can have, for example, a further connection piece 82, which has an external thread 83. For example, the second component 62 can be designed as a double connector 62. The further connector 82 can serve on the external thread 83 for a releasable screw connection. In this case, a line can be screwed on and unscrewed repeatedly. For example, the further connection piece 82 can be designed such that screwing on and unscrewing is possible at least 25 times. The mechanical loads during screwing on and unscrewing could then lead to a rotation of the connecting piece 64 relative to the first component 61, which is however prevented by the anti-loosening means achieved by the microencapsulated adhesive 70.Advantages also result if the first component 61 and the second component 62 are formed from different materials. In particular, one component 61, 62 can be formed from a steel and the other component 61, 62 from an aluminum. Corrosion is then avoided. Specifically, in this embodiment, the first member 61 may be made of aluminum while the second member 62 is made of steel.In this exemplary embodiment, a sealing element 90 is provided, which can be designed as a sealing ring 90 and / or flat seal 90. A seal is formed between the first component 61 and the second component 62 by the sealing element 90.FIG. 4 shows the first component 61 shown in FIG. 2 and the second component 62 and its connector 64 in a pull-out schematic illustration corresponding to a second exemplary embodiment. In this exemplary embodiment, a bite edge 95 is provided on the connecting piece 64, by means of which a seal is formed between the first component 61 and the second component 62. Thus, sealing over the bite edge 95 and bonding over the microencapsulated adhesive 70 may be combined.A component 90 of a fuel injection system 10, which serves for injecting gaseous fuels, in particular hydrogen, into combustion chambers 11 of an internal combustion engine, can thus be realized, wherein a first component 61 having a bore 63 and a second component 62 having a connecting piece 64 are provided, and wherein the second component 62 is connected at its connecting piece 64 to the first component 61 by a connection 60. Furthermore, a fuel injection system 10, which serves for injecting gaseous fuels, in particular hydrogen, into combustion chambers 11 of an internal combustion engine, can be realized, at least one such component 90 being provided.Modifications for liquid fuels, in particular gasoline, are also possible.As is shown by way of example in FIG. 1, the connection 60 can be used in particular at the points 65. A plurality of devices of the fuel injection system 10 are suitable as component 90. Particularly preferably, the connection 60 is used on a pressure regulator 22, 30. The connection 60 can be provided on the connecting piece 54 and / or on the outlet-side connecting piece 56. The connection 60 can also be provided in particular on the integrated unit 16, on the filter 20, on the filter 26, if this is an individual element, and on the temperature control device 28. Particularly preferably, the connection 60 can additionally or alternatively be provided on the fuel distribution device 38, in particular rail 38.The invention is not limited to the described exemplary embodiments.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2006 040 236 A1 [0002, 0003]
Claims
Connection (60) for a fuel system (10) which serves for blowing gaseous fuels, in particular hydrogen, and / or for injecting liquid fuels, in particular petrol, into combustion chambers (11) of an internal combustion engine, wherein a first component (61) of the fuel system (10) and a second component (62) of the fuel system (10) are provided, wherein the first component (61) has a bore (63), wherein the second component (62) has a stub (64) which is inserted into the bore (62) of the first component (61), and wherein the second component (62) is connected at its stub (64) to the first component (61), characterized in that the first component (61) has a thread (76), the connecting piece (64) of the second component (62) has a thread (75), and in order to connect the second component (62) at its connecting piece (64) to the first component (61), the connecting piece (64) is screwed with its thread (75) into the thread (76) of the first component (61), wherein the thread (75) of the connecting piece (64) and / or the thread (76) of the first component (61) is provided at least partially with an adhesive (70) which is microencapsulated before the screwing.The compound of claim 1, characterized in that the microencapsulated adhesive (70) comprises at least two components (78, 79), wherein at least one component (78) of the adhesive (70) is enclosed in microcapsules (80) surrounded by another component (79) of the adhesive (70).Connection according to Claim 1 or 2, characterized in that at least between two and three thread turns (72) of the thread of the connector (64) are provided at least substantially continuously with the adhesive (70) which has been microencapsulated before screwing, and / or in that at least between two and three thread turns (73) of the thread (76) of the first component (61) are provided at least substantially continuously with the adhesive (70) which has been microencapsulated before screwing.Connection according to one of Claims 1 to 3, characterized in that the connection piece (64) is screwed with its thread (75) into the thread (76) of the first component (61) in such a way that a non-rotation prevention means is formed by the adhesive (70) which has microencapsulated before the screwing.Connection according to one of Claims 1 to 4, characterized in that the connection piece (64) is screwed with its thread (75) into the thread (76) of the first component (61) in such a way that a watertight connection is formed by the adhesive (70) which has been microencapsulated before the screwing.Connection according to one of Claims 1 to 5, characterized in that the first component (61) and the second component (62) are formed from different materials, in particular a steel and an aluminium.Connection according to one of Claims 1 to 6, characterized in that at least one sealing element (90), in particular a sealing ring (90) and / or a flat seal (90), is provided, by means of which a seal is formed between the first component (61) and the second component (62), and / or b) in that at least one bite edge (95) is provided, by means of which a seal is formed between the first component (61) and the second component (62).Connection according to one of Claims 1 to 7, characterized in that the second component (62) has a further connecting piece (82) which has an external thread (83), and in that the further connecting piece (82) serves for a releasable screw connection provided on the external thread (83) of the further connecting piece (82).Component (90), in particular a pressure regulator (22, 30) or a fuel distribution device (38), of a fuel system (10) which serves for blowing gaseous fuels, in particular hydrogen, and / or for injecting liquid fuels, in particular petrol, into combustion chambers (11) of an internal combustion engine, wherein a first component (61) having a bore (63) and a second component (62) having a connecting piece (64) are provided, and wherein the second component (62) is connected at its connecting piece (64) to the first component (61) by a connection (60) according to one of Claims 1 to 8.Fuel system (10) which serves for blowing gaseous fuels, in particular hydrogen, and / or for injecting liquid fuels, in particular petrol, into combustion chambers (11) of an internal combustion engine, wherein at least one component (90) according to Claim 9 is provided.