Connecting piece with integrated particle filter for a component of a fuel-supply system for supplying an internal combustion engine with hydrogen

Abstract

According to the invention, a particle filter (60) is inset in a connecting piece (50) for a component of a fuel-supply system for supplying an internal combustion engine with gaseous fuel, for example hydrogen. Further measures are proposed to reduce the flow resistance of the device.

Description

[0001] Description

[0002] title

[0003] Connection piece with integrated particle filter for a component of a fuel supply system for supplying an internal combustion engine with hydrogen

[0004] State of the art

[0005] From the subsequently published DE 10 2023 206 379 A1 of the applicant, a connection piece with an integrated particle filter for a component of a fuel supply system for supplying an internal combustion engine with gaseous fuel is already known.

[0006] Disclosure of the invention

[0007] According to the invention, a connecting piece is provided for a component of a fuel supply system for supplying an internal combustion engine with gaseous fuel, e.g. hydrogen, which has a particle filter integrated therein.

[0008] For example, the particulate filter can be completely enclosed within the casing of the connection piece. The particulate filter can also be spaced at least 1 mm from the outlet planes (for example, the end faces in the case of a straight piece). The connection piece can then be handled as usual, for example, for connecting it to the component, without any risk of damaging the particulate filter.

[0009] According to the invention, the particulate filter has a press-in section by means of which it is held in the connecting piece in a press fit. In the uninstalled state, the particulate filter therefore has an outer diameter in the region of the press-in section which has a press-in interference fit compared to an inner diameter of the connecting piece. The press-in interference fit can, for example, be at least 25 pm, for example 55 pm to 200 pm, in the case of a connecting piece which has a thread of size M16 to M20 for screwing to the component. In the installed state, the resulting elastic compression of the particulate filter in the region of the press-in section produces a corresponding press-in force which securely holds the particulate filter in the connecting piece in a force-fitting manner even when the gaseous fuel flows through it.

[0010] The particulate filter can, for example, have a sleeve-shaped base made of a plastic. This can be a glass fiber-reinforced polymer, such as PA 66 GF 25 or PA 66 GF 35, as these materials are relatively brittle, have little tendency to crack, and are easy to process by injection molding.

[0011] A metal sleeve, such as one made of stainless steel, can be fixed to the sleeve-shaped base. Compared to brass-containing sleeves, this offers the advantage of greater chemical resistance, for example, to water potentially present in the gaseous fuel and during the injection process.

[0012] By providing the metal sleeve, the pressing forces can be applied reliably and the particulate filter can be held permanently in the connection piece by means of pressing.

[0013] The sleeve-shaped base part can have one or more metal mesh parts along its circumference, which provide the filtering effect of the particle filter. The metal mesh can, for example, have a mesh size of 10 μm.

[0014] The connection piece may have an annular step on its inner contour facing the particulate filter for axially supporting the particulate filter when pressed in. The annular step can serve as an assembly stop for the particulate filter during installation in the connection piece.

[0015] The annular step can be flat. The plane defined by the annular step can be oriented orthogonally to the axis of the connecting piece.

[0016] If such an annular step is provided, the inner diameter of the connecting piece transitions from a narrower inner diameter of the connecting piece to a wider inner diameter of the connecting piece at the annular step. It may be provided that the narrower inner diameter of the connecting piece is also the narrowest inner diameter of the connecting piece with regard to the entire inner contour of the connecting piece.

[0017] Further developments of the invention aim to keep the flow resistance resulting from the integration of the filter into the connection piece within specified limits. For example, the pressure drop across the particulate filter should always be less than 0.5 bar when flow is passing through the connection piece or through the component.

[0018] For this purpose, it can be provided that the inner diameter of the particulate filter, or the inner diameter of the base part of the particulate filter at its end facing the annular step, i.e., the inlet diameter of the particulate filter, is not smaller than the narrower inner diameter of the connection piece. This measure allows the gaseous fuel to flow into the filter unthrottled.

[0019] For this purpose, it can additionally or alternatively be provided that an annular channel formed between the particulate filter, in particular between the base part of the particulate filter, and the internal geometry of the connecting piece has a cross-sectional area that is not smaller than the cross-sectional area of ​​the connecting piece in the region of the narrower internal diameter of the connecting piece. The gaseous fuel can then flow to the component after filtering through the annular channel of the connecting piece without throttling. Pressing the particulate filter into the connecting piece entails certain mechanical loads or deformations of the connecting piece. Likewise, mounting the connecting piece on the component entails mechanical loads or deformations.Deformations of the connecting piece are associated with this, for example when the connecting piece is screwed onto the component, where, for example, a biting edge of the connecting piece comes into axial contact with the component with a certain force.

[0020] In order to prevent mechanical loads or deformations of the connecting piece of the first-mentioned type from interacting in a harmful manner with mechanical loads or deformations of the connecting piece of the last-mentioned type, it can be provided that the press-in section is arranged in a part of the connecting piece facing away from the component in the axial direction.

[0021] The part of the connecting piece facing away from the component can extend over one-third of the axial extent of the connecting piece or over half of the axial extent of the connecting piece. The loads or deformations occurring at the connecting piece are then largely decoupled from each other due to the distance between the locations where they occur.

[0022] The connecting piece can be provided with a mounting profile, for example, an external hexagon profile. This is used, for example, when screwing the connecting piece into the component to introduce a torque into the connecting piece or to cause it to rotate around its longitudinal axis. In this case, the aforementioned part of the connecting piece facing away from the component can also be provided by the area of ​​the connecting piece that lies on the side of the mounting profile facing away from the component.

[0023] As intended, a line for supplying the gaseous fuel can be mounted, for example, by screwing, on the side of the connection piece facing away from the component. To ensure that the connection piece can absorb the torques that occur when securing the screw connection, the wall thickness of the connection piece is at least 1.2 mm throughout, particularly within any constriction in the wall of the connection piece that may be located on a side of the connection piece facing away from the component.

[0024] Further developments of the invention aim to keep the flow resistance resulting from the provision of the connection piece with a particle filter on the component within specified limits. For example, the pressure drop when flowing through the component should always be less than 0.5 bar.

[0025] For this purpose, the component may be provided with a connection piece as described above. In this case, the component has a housing through which a fluid channel runs, allowing the gaseous fuel to flow into the fluid channel through the connection piece.

[0026] For this purpose, the fluid channel can also be provided with a beveled shape that widens toward the connecting piece. The bevel angle, i.e., the angle at which the wall of the fluid channel is inclined to the axis of the fluid channel in the region of the bevel, can be between 5° and 25°. This reduces the flow resistance to which the gaseous fuel is exposed during the transition from the connecting piece into the fluid channel. The bevel angle can be, for example, 15°.

[0027] Additionally or alternatively, for this purpose, it can be provided that the opening of the fluid channel facing the connection piece has an opening diameter and the inner contour of the connection piece facing the fluid channel has an inner diameter, wherein the quotient of the opening diameter to the inner diameter is not less than 0.7. It can be provided that the said quotient is not greater than 0.9. The choice of the quotient enables an unthrottled flow of the gaseous fuel during the transition from the partial area inside the connection piece, which lies radially outside the particulate filter, into the fluid channel of the component housing.

[0028] The component may, for example, be a high-pressure regulator or a fuel rail, so that the invention particularly also encompasses such components with a connecting piece designed according to the invention, for example an inlet piece or an outlet piece.

[0029] Embodiments of the present invention are explained below with reference to the accompanying drawings, in which:

[0030] Figure 1 a fuel supply system

[0031] Figure 2 shows an embodiment of the invention.

[0032] A fuel supply system is designated overall by reference number 10 in Figure 1. It serves to supply an internal combustion engine (not shown) with a fuel, in particular a gaseous fuel, in this case, for example, gaseous hydrogen.

[0033] The hydrogen is stored under high pressure, for example, approximately 700 bar, in a tank-like fuel storage unit 12. This can be filled via a filling connection 14. Furthermore, an integrated unit 16 consisting of a tank valve for filling and discharging hydrogen into and from the fuel storage unit 12 and a temperature sensor for detecting the temperature of the gaseous hydrogen coming from the fuel storage unit 12 is arranged on the fuel storage unit 12.

[0034] The gaseous hydrogen first flows via a pressure line 18 to a high-pressure filter 20 and from there to a high-pressure pressure regulator 22. This reduces the pressure of the gaseous hydrogen to, for example, a pressure in the range of 40 bar. The pressure line 18 leads from the high-pressure pressure regulator 22 to a high-pressure pressure sensor 24, another high-pressure filter 26, an optional temperature control device 28, and finally to a pressure regulator 30.

[0035] The pressure control device 30 comprises a shut-off valve device 32, downstream of which are two hydraulically parallel pressure control valves 34, and a pressure sensor 35 between the shut-off valve device 32 and the two pressure control valves 34. The two pressure control valves 34 are identically constructed and are typically proportional valves. The pressure control device 30 further reduces the pressure in the pressure line 18 from the inlet-side pressure, which is exemplary here, of approximately 40 bar to a pressure of, for example, approximately 15 bar. The shut-off valve device 32 upstream of the pressure control valves 34 is closed when the fuel supply system 10 is not in operation. This prevents unwanted gas leakage.

[0036] Downstream of the pressure control device 30, the pressure line 18 leads to a distribution chamber 36, which can be designed, for example, as an elongated tube, similar to a typical fuel rail as known from gasoline and diesel fuel systems. The gas pressure prevailing in the distribution chamber 36 is detected by a further pressure sensor 37.

[0037] Connected to the distribution chamber 36 are several injectors 38, which inject the gaseous hydrogen directly into combustion chambers 40 of the internal combustion engine, as an example here. The gaseous hydrogen is mixed with atmospheric oxygen in the combustion chambers 40, and this mixture is ignited by a respective ignition device 42. Typically, the internal combustion engine is a 2-stroke or 4-stroke piston internal combustion engine. For example, such an internal combustion engine is used to power a motor vehicle. However, it can also be used stationary, for example, to drive a generator for power generation.

[0038] The fuel supply system 10 and its components are controlled by an electronic control and regulating device 44, which has one or more corresponding microprocessors. This receives signals from, among others, the temperature sensor 16, the high-pressure pressure sensor 24, the pressure sensor 35, the additional pressure sensor 37, etc. The control and regulating device 44 controls various components of the fuel supply system 10, including the pressure regulating device 30 and the ignition devices 42. Furthermore, a control device 46 is also controlled by the control and regulating device 44, which in turn specifically controls or regulates the operation of the fuel storage device 12. One embodiment of the invention is shown in Figure 2. Figure 2 shows a connection piece 50; in the example, this is an inlet piece for a pressure regulating device 30 (see also Figure 1).

[0039] The inlet nozzle 50 has an external thread 58, the size of which ranges from M16 to M20. The external thread 58 screws the inlet nozzle 50 into a matching internal thread of the pressure regulator 30, allowing gaseous fuel to flow through the inlet nozzle 50 into a fluid channel 30b formed in a housing 30a of the pressure regulator 30. The inlet nozzle 50 abuts axially against a contact surface 30c of the component 30 with a gas-tight sealing bite edge 53.

[0040] The inlet nozzle 50 further comprises, upstream of the external thread 58, a mounting profile 59 designed as an external hexagon and, again upstream of this, offset via a constriction 54, a connection area for a gas line, which is only shown in Figure 1.

[0041] The wall 50a of the inlet nozzle 50 is always no thinner than 1.2 mm, even in the area of ​​the constriction 54. Installation torques of, for example, up to 60 Nm applied to the inlet nozzle 50 can therefore distort the inlet nozzle 50.

[0042] The inner contour 56 of the inlet nozzle 50 has, opposite the contact surface 30c of the component 30 and up to a region 50b of the inlet nozzle 50 which lies at the axial height of the mounting profile 59, an inner diameter di which is approximately 1.25 times the diameter dm of the mouth of the fluid channel 30b opposite the inlet nozzle 50.

[0043] Starting from the mouth of the fluid channel 30b opposite the inlet nozzle 50, the fluid channel 30b is tapered by means of a chamfer having a chamfer angle a of 15°, for example such that the diameter ds of the fluid channel 30b downstream of the chamfer is still 70% of the diameter of the mouth dm of the fluid channel 30b opposite the connection nozzle.

[0044] Starting from the area 50b, which lies at the axial height of the mounting profile 59, the inner contour 56 of the inlet nozzle 50 tapers conically in the upstream direction to a hollow cylindrical press-in area 51 of the inlet nozzle 50. Via a radially oriented annular step 57, the press-in area 51 merges into an inflow area 80 of the inlet nozzle 50. The diameter dw of the inlet nozzle 50 in the press-in area is wider than the diameter de of the inlet nozzle 50 in the inflow area, or it is narrower in the inlet area than in the press-in area.

[0045] A particulate filter 60 is integrated into the inlet nozzle 50. In the example, the particulate filter 60 has a base part 62 made of the plastic PA 66 GF25, which has the shape of a sleeve 62 open on the upstream side and a closed bottom 62c arranged on the downstream side. One or more metal mesh parts, in the example with a mesh size of 10 μm, are accommodated on the essentially cylindrical periphery 62a of the base part 62, which serve to filter the gaseous fuel.

[0046] The particle filter 60 is completely accommodated in an envelope of the connecting piece 50 and the closed bottom 62c of the base part 62 is in the example 1 mm from the plane 55 in which the downstream mouth of the inlet piece

[0047] 50, spaced.

[0048] In the upstream, open end region of the base part 62, the peripheral wall 62a of the base part 62 has a projection 62e, on which a metal sleeve 63 is fixed, which in the example is made of stainless steel. The metal sleeve 63 forms a press-in section 61 of the particulate filter 60 in the example. Via this press-in section 61, the particulate filter 60 is in the press-in area

[0049] 51 of the inlet nozzle 50 is held in a press fit.

[0050] During the pressing of the particulate filter 60 into the inlet nozzle 50, the annular step 57 of the inlet nozzle 50 serves as an axial stop for the metal sleeve 63 of the particulate filter 60. When the particulate filter 60 is mounted in the inlet nozzle 50, the metal sleeve 63 then rests axially against the annular step 57 of the inlet nozzle 50. To minimize the resistance that the inlet nozzle 50 offers to its flow, the design provides that an inner diameter dp of the particulate filter 60, in particular an inner diameter dp of the base part 62 of the particulate filter 60, at its end face 62b facing the annular step 57, is not smaller than the narrower diameter de of the inlet nozzle 50.

[0051] In order to minimize the resistance that the inlet nozzle 50 offers to the flow through it, it is structurally provided that an annular channel 70 formed between the particle filter 60, in particular between the base part 62 of the particle filter 60, and the inner geometry 56 of the connecting nozzle 50 has a cross-sectional area that is not smaller than the cross-sectional area of ​​the inlet nozzle 50 in the region of the narrower diameter de.

Claims

Claims 1 . Connection piece (50) with integrated particle filter (60) for a component (30) of a fuel supply system for supplying an internal combustion engine with gaseous fuel, in particular with hydrogen, wherein the particle filter (60) has a press-in section (61) by means of which it is held in the connection piece (50) in a press fit 2. Connection piece according to claim 1, wherein the particle filter (60) has a sleeve-shaped base part (62) made of a plastic, on which a metal sleeve (63) is fixed, and wherein the particle filter (60) is held in a press fit in the connection piece (50) via the metal sleeve (63).

3. Connection piece according to claim 2, wherein the sleeve-shaped base part (62) receives on its circumference (62a) one or more metal mesh parts which serve to filter the gaseous fuel.

4. Connection piece according to one of the preceding claims, wherein the particle filter (60) is arranged completely in an envelope shape of the connection piece (50).

5. Connection piece according to claim 4, wherein the particle filter (60) is spaced at least 1 mm from the mouth planes (55) of the connection piece (50).

6. Connection piece according to one of the preceding claims, wherein the connection piece (50) has on its inner contour (56) an annular step (57) facing the particle filter (60) for axially abutting the particle filter (60) in the pressed-in state, at which the inner diameter of the connection piece (50) changes from a narrower diameter (de) to a wider diameter (dw).

7. Connection piece according to claim 6, wherein an inner diameter (dp) of the particle filter (60), in particular an inner diameter (dp) of the base part (62) of the particle filter (60), at its end face (62b) facing the annular step (57) is not smaller than the narrower diameter (de).

8. Connection piece according to claim 6 or 7, wherein an annular channel (70) formed between the particle filter (60), in particular between the base part (62) of the particle filter (60), and the inner contour (56) of the connection piece (50) has a cross-sectional area which is not smaller than the cross-sectional area in the interior of the connection piece (50) in the region of the narrower diameter (de).

9. Connection piece according to one of the preceding claims, wherein the press-in section (61) is arranged in a part of the connection piece (50) facing away from the component (30) in the axial direction (100).

10. Connection piece according to claim 9, wherein the connection piece (50) has a thread (58) and a mounting profile (59), for example an external hexagon profile, wherein the press-in section (61) is arranged beyond the mounting profile (59) as seen from the component (30).

11. Component (30) of a fuel supply system for supplying an internal combustion engine with gaseous fuel, in particular with hydrogen, with a connecting piece (50) according to one of the preceding claims, wherein the component (30) has a housing (30a) through which a fluid channel (30b) runs, so that the gaseous fuel can pass through the connecting piece (50) into the fluid channel (30b).

12. Component according to claim 11, wherein the fluid channel (30b) widens towards the connecting piece (50) in the form of a chamfer having a chamfer angle (a) of 5° to 25°.

13. Component according to claim 11 or 12, wherein the mouth (55) of the fluid channel (30b) facing the connection piece (50) has a mouth diameter (dm) and wherein the fluid channel (30b) facing inner contour (56) of the connecting piece (50) has an inner diameter (di), wherein the quotient of mouth diameter (dm) to inner diameter (di) is not less than 0.7 and not greater than 0.

9.

14. Component according to one of claims 11 to 13, wherein the component (30) is designed as a high-pressure regulator, with at least one electrically controllable valve (32, 34) for interrupting and / or throttling a flow through the fluid channel (30b) with the gaseous fuel, in particular with the hydrogen.

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