VALVE SYSTEM

Description

[0001] The present invention relates to a valve device for exhaust gas recirculation in an exhaust system of a motor vehicle powered by an internal combustion engine.

[0002] In modern combustion engines, a portion of the exhaust gases is recirculated to the combustion process within the engine to reduce emissions. Due to pressure pulsations caused by the combustion process, the pressure on one side of the exhaust gas recirculation (EGR) system can be briefly lower than the pressure on the other side. This pressure difference would lead to an unwanted backflow of exhaust gas into the EGR system. To prevent this, valve devices known as EGR check valves are used, which can only open towards the charge air side. A valve device suitable for this purpose is known from the prior art, including DE 199 53 198 A1. A valve device according to DE 10 2005 059 120 B3 also features a substantially rectangular flange geometry.It is known to implement such check valves in various designs, e.g., from modularly stacked and bolted or welded sheet metal layers, or from a cast body with sheet metal layers attached to it. This design, consisting of a cast body with sheet metal layers, requires not only a large number of components but also a very large installation space and a high overall weight. Other valve assemblies are known from DE19830230A1 or DE202007004323U1.

[0003] One problem with known EGR check valves is that, with a smaller valve geometry, the resulting pressure loss is no longer functionally acceptable.

[0004] Furthermore, the modular valve design is limited in terms of manufacturability and durability.

[0005] The objective of the present invention is therefore to create a valve device that can be used as an EGR check valve, in which pressure loss is reduced compared to known valve designs, even with small valve geometries.

[0006] This problem is solved according to the invention by the features of claim 1 or by the features of claim 14 in that the valve assembly comprises a valve body, which is designed as a separate part and is shaped like a mushroom or umbrella, and is axially guided in a gas-flowing area in a carrier plate. In a closed position, the valve body rests with its umbrella on the carrier plate, sealing the gas-flowing area, and has an end stop for an open position in which the gas-flowing area is maximally released. A valve assembly according to the invention thus comprises a movable valve body that essentially has the shape of a mushroom fruiting body or an open canopy. The fruiting body of a classic mushroom consists of a stem and a cap; a canopy, with a comparable external structure, consists of a canopy and a stem.In both visual comparisons, the hat and canopy clearly serve as a seal in the closed end position of the valve on or against the carrier plate, sealing the gas-through area. Lifting the valve body, which is freely movable axially along the stem or piece, from the carrier plate opens the valve by releasing the gas-through area within the carrier plate.

[0007] In the proposed solution, the valve body, with its distinctive external shape, is guided in its movement between two endpoints. This results in a compact valve design that allows for significantly larger cross-sections, thus reducing the pressure loss. Since this design lacks a return element, such as a spring or even a leaf spring clamped at the end, the response to changes in pressure conditions on either side of the valve body is improved, as no spring forces need to be overcome. The resulting boost or exhaust pressure thus keeps the valve either closed or open. This allows the valve to open or close at significantly smaller pressure differences. A valve assembly according to the invention is very compact and can therefore be used in very confined spaces and, advantageously, also in non-rectangular installation spaces.

[0008] Advantageous further developments are the subject of the respective dependent claims. Accordingly, a stopper layer forms the end stop for the mushroom- or umbrella-shaped valve body in the open position. The support plate and stopper layer form a stack of easily manufactured sheet metal sections between which the valve body is movable.

[0009] Advantageously, the mushroom- or umbrella-shaped body is guided by a rod in a recess of the support plate and / or the stopper. This guidance in the support plate and / or the stopper is achieved by the slidable mounting of the stem of the mushroom or the shaft of the umbrella as a rod within the support plate and / or the stopper. Such a rod has a straight length in one direction of movement of the valve body, which is sufficient for axial guidance in a suitably sized hole.

[0010] In a preferred embodiment of the invention, the carrier plate and the stopper layer have at least one recess for exhaust gas flow and a sliding bearing for guiding the valve body rod. This allows for simple designs of the carrier plate and the stopper layer, which can be manufactured, in particular, as simple stamped or laser-cut parts. In one embodiment of the invention, a three-dimensionally deformed stopper layer with at least one flow opening forms the end stop for the mushroom- or umbrella-shaped valve body. The stopper layer thus defines a maximum valve stroke.

[0011] In an advantageous embodiment of the invention, the at least one recess in the carrier plate and in the stopper position is congruently formed and aligned in the direction of exhaust gas flow. This minimizes turbulence and deflection in the area of ​​the recesses, which would otherwise have a negative impact in the form of increased pressure loss.

[0012] In a further development of the invention, the support plate and the stopper layer have recesses corresponding to a screw hole for bolting the end flanges. This allows the described arrangement to be directly combined with standard flanges and easily bolted together to create a permanently sealing connection.

[0013] Preferably, the stopper layer and the carrier plate are at least partially connected to each other by force-fit, form-fit, and / or material-fit connection. This results in a valve assembly according to the invention as an easily handled and simple-to-install unit with the movable valve body between the carrier plate, which is firmly joined to the stopper layer. This connection between the stopper layer and the carrier plate is preferably located outside a sealing layer, as will be illustrated below with reference to an exemplary embodiment.

[0014] According to a particularly advantageous embodiment of the invention, the stopper layer and the support plate are each designed as seals. These seals ensure a permanently and reliably tight seal between the flanges of a pipe connection or a pipe fixing to a housing part, even in temperature ranges exceeding 200°C.

[0015] In one embodiment of the invention, the valve body is guided as a sliding bearing in the form of a sleeve; in one exemplary embodiment of the invention, two sleeves are provided for the guides. It is known to those skilled in the art that a sleeve can be easily and reliably fixed permanently in a recess, taking into account known material pairings. Instead of using sleeves in the form of separate components, a single-material solution can also be chosen, for example, by folding and / or deep-drawing an existing material of the relevant sheet metal part as a guide. Both measures can provide axial guidance for the valve body stem. Friction-reducing coatings known to those skilled in the art can be easily applied in this area, so that at least one additional component can be eliminated.

[0016] In a further development of the invention, the valve assembly has at least one additional seal that improves the sealing functionality between the flanges. This additional seal is preferably designed as a metal corrugated gasket that provides a very good seal even at high temperatures and with large temperature fluctuations.

[0017] In all described further developments of the invention, the mushroom- or umbrella-shaped valve body itself is manufactured in one piece as an injection-molded, molded, milled, or turned part. The valve body consists of a thermally resistant material, such as a metal or plastic.

[0018] According to claim 14, the mushroom- or umbrella-shaped valve body is provided with a rod in the form of a hollow, cylindrical stem, which has openings adjacent to the umbrella. These openings are preferably uniformly shaped and distributed around the circumference of the rod such that, in a second endpoint position, they are closed by the sliding sleeve and the umbrella is arranged to rest sealingly on the support plate. In a first endpoint position, or open end position, these openings are uncovered.

[0019] As an alternative to defining the second endpoint position of the valve assembly by means of a stop position, the valve body stem has at least one detent lug or an outwardly directed collar, formed, for example, by flanging or similar material forming, at a free end. The detent lug or collar, together with an axial guide, then defines a maximum stroke of the valve body in the second endpoint position.

[0020] Further features and advantages of embodiments of the invention are explained in more detail below with reference to exemplary embodiments and the drawing. The drawing schematically depicts: Figures 1a to 1d : a top view of a first embodiment of a valve device with sectional views in a plane AA with the valve device open and closed, as well as an exploded view; Figures 2a to 2d : a representation of a second embodiment of a valve device analogous to the Figures 1a to 1d ; Figures 3a to 3d : a representation of a third embodiment of a valve device analogous to the Figures 1a to 1d ; Figures 4a to 4e : a representation of a fourth embodiment of a valve device analogous to the Figures 3a to 3das well as a sectional view to illustrate the sealing functionality of this assembly consisting of stopper layer, carrier plate and additional bead seals for sealing between the flanges; Figure 5 : a representation of a fifth embodiment of a valve device analogous to the illustrations of the Figures 1c and 2c and Figures 6a to 6e : a variation of the exemplary embodiment of Figure 5 in sectional views, perspective views from above and below, and an exploded view.

[0021] Across the various illustrations and examples, the same reference symbols are always used for identical elements.

[0022] The sketch of Figure 1aFigure 1 shows a top view of a first embodiment of a valve assembly 1, which is clamped between two flanges 2, 3 as a section of an exhaust gas recirculation system (not shown) in the exhaust stream of a motor vehicle powered by an internal combustion engine. An internal structure is shown in the sectional view in a plane A - A of the Figure 1a clarifies, which as Figure 1b the valve assembly 1 in the closed and Figure 1cThe valve assembly 1 is shown in its open state. The valve assembly 1 has a valve body 4, which is designed as a separate, rotationally symmetrical, mushroom- or umbrella-shaped body. This valve body 4 is guided axially between two endpoints in a recess 6 of a carrier plate 5. Three recesses 7 are radially distributed around the recess 6. In an open position of the valve assembly 1, an exhaust gas flow passes through these recesses, thereby opening the valve body 4 as shown. In this open position, the first endpoint, the valve body 4 rests against an end stop formed by a cap-shaped stop 9 with flow openings 8. In a closed position, the second endpoint, the valve body 4 rests sealingly against the three recesses 7 and the carrier plate 5.

[0023] The recess 6 in the carrier plate 5 is provided with a sliding sleeve 10, which can be made of Teflon, copper, and / or stainless steel. A rod 11 of the valve body 4 is axially displaceably mounted in this sliding sleeve 10, so that the recesses 7, which serve as flow openings in the carrier plate 5, are sealed by pressing a head 12 of the valve body 4 onto the carrier plate 5. The valve assembly 1 thus comprises only a mushroom- or umbrella-shaped valve body 4, consisting of a head 12 and a rod 11, which is guided between two end positions in the carrier plate 5 by its rod 11. The carrier plate 5 forms an end stop for a closed end position, and the cap-shaped stopper position 9 forms a second end stop with adjustment for a maximum opening or a valve stroke h of the valve assembly 1 (see figure). Figure 1c .

[0024] The flow through the valve assembly 1 is improved compared to known EGR check valves, among other things, by the fact that here a free pipe cross-section A can be almost completely utilized by the valve body 4 with a diameter a of the head 12, as shown in Figure 1b As indicated, beyond the area of ​​the recess 6, a large proportion of the free pipe cross-sectional area A on the support plate 5 is available for forming flow openings in the form of the recesses 7. Thus, such a valve assembly 1 advantageously exhibits a comparatively low flow resistance.

[0025] The valve assembly 1 is also designed as a seal, which is permanently sealed between the flanges 2 and 3. For this purpose, the support plate 5 and the stopper position 9 have an external shape that corresponds to the standard shape of the flanges 2 and 3. Furthermore, the support plate 5 and the stopper position 9 also have screw holes 13 that are aligned with the line of the screw connection of the flanges 2 and 3.

[0026] The illustrations of Figures 2a to 2d show illustrations of a second embodiment of a valve device analogous to the Figures 1a to 1d , in which a guide 14 of the mushroom- or umbrella-shaped valve body 4 is now provided in the stopper position 9. The valve body 4, by virtue of the shape of its head 12, represents a quasi-inverted umbrella. The valve body 4 can also be operated from the Figures 1a to 1dcan be inserted rotated by 180°. Furthermore, the head 12 can also receive additional guidance within the deep-drawn structure of the stopper position 9.

[0027] The opening 7 in the carrier plate 5 can be chamfered (not shown) to provide additional self-centering in the area of ​​the head 12 of the valve body 4 when closing on the now single opening 7. This results in a diameter b of a single circular recess in the carrier plate 5 as a flow-through opening, which can be selected to be only slightly smaller than the diameter a of the head 12 of the valve body 4 without impairing the sealing of the valve assembly 1 (see figure). Figure 2b Consequently, this embodiment is characterized by a particularly low flow resistance due to the favorable flow guidance.

[0028] The illustrations of Figures 3a to 3dshow a representation of a third embodiment of a valve device analogous to the Figures 1a to 1d In this embodiment, a second guide 14 for the mushroom- or umbrella-shaped valve body 4 is provided in the stopper position 9 to ensure even more secure guidance of the valve body 4. For this purpose, the rod 11 of the valve body 4 has been extended accordingly over the head 12, so that guides in the form of sliding sleeves 10, 14 ensure axial guidance of the valve body 4 at all times. In this embodiment, guides for the rod 11 of the umbrella valve 4 are thus provided in both the stopper position 9 and the support plate 5. The rod 11 of the valve body 4 is therefore slidable once in the support plate 5 and a second time in the stopper position 9, and guided by the sliding sleeves 10, 14 with low friction. In this way, the movable valve body 4 is secured against tilting even more reliably than by a single axial guide alone.

[0029] the illustrations of Figures 4a to 4e show a fourth embodiment of a valve device 1 analogous to the Figures 2a to 2d , in which the valve assembly 1 has at least one additional seal. In this embodiment, two additional seals 15, 16 are provided downstream of the stopper position 9 and the support plate 5. The seals 15, 16 are provided to improve the sealing function of the valve assembly 1 against the flanges 2, 3 and are designed as metal bead seals in this embodiment.

[0030] Furthermore, the stopper layer 9 and the support plate 5 are connected to each other by rivets 17 via the two additional seals 15, 16. These rivets 17 are located outside of an actual sealing area and thus also outside of the flanges 2, 3. The sectional view of Figure 4eFigure 1 shows an illustration of the improved sealing functionality achieved by this assembly consisting of stopper layer 9, carrier plate 5 and additional bead seals 15, 16 between the flanges 2, 3 with a cut rivet 17.

[0031] Figure 5Figure 1 shows a representation of a fifth embodiment of a valve device 1. Here, the valve body 4 is provided with a rod 11 in the form of a hollow, cylindrical stem. The rod 11 has openings 18 adjacent to the head or shield 12, which in this example are arranged evenly distributed around the circumference. These openings are only fully released when the valve body 4 rests against the stop position 9, i.e., in the open end position. In contrast to the embodiments described above, the carrier plate 5 no longer has flow openings 8 distributed radially around the recess 6, but only openings 18. In a second end position, the shield 12 rests sealingly against the carrier plate 5.

[0032] The illustrations of Figures 6a to 6e represent a variation of the exemplary embodiment of Figure 5This is shown in such a way that in this example the carrier plate 5 is double-layered and, instead of using a sliding sleeve, the adjacent material of the sheet metal parts 5, 5 has been deep-drawn in a mirror image to form an axial guide 19. From the sectional view of Figure 6a It is further evident that a stop position 9 is no longer provided to define a second endpoint of the valve body 4. Instead, locking lugs 20 are provided at a free end 21 of the hollow stem 11, which together with the axial guide 19 define a maximum stroke h of the valve body 4. Figure 6c shows the compact design of this embodiment in a perspective top view in the fully open position. Figure 6dFigure 1 shows a corresponding view from below for a better illustration of the locking lugs 20 used here in conjunction with the axial guide 19. This illustration makes it clear that the use of at least one locking lug 20 at the free end 21 is not limited to an embodiment with a valve body 4 having a hollow stem 11. Using an alternative manufacturing method, a collar circumferentially encircling the outside of the free end 21 can also be provided as a second end stop instead of a locking lug 20; this is not shown in further detail in the drawing.

[0033] Figure 6eFigure 1 shows an example of a simple assembly of this embodiment in the form of an exploded view. Simply by inserting the valve body 4, all components can be fixed in a position relative to each other. The previously mentioned fixings of components to one another are also possible to simplify quick and secure installation, but these are not shown in detail here.

[0034] The mushroom- or umbrella-shaped valve body 4, together with the rod 11 and head 12, is formed in one piece as an injection-molded, molded, milled, or turned part, and is made of a material that can withstand temperatures up to approximately 300°C. In all the embodiments described above, the mushroom- or umbrella-shaped valve body 4 closes automatically depending on the applied pressure and does not require an additional restoring force, such as that which, in known devices, must be achieved, for example, by an elastically pre-tensioned spring. Due to its low mass, the described valve assembly 1 is also characterized by a rapid response time.

[0035] Furthermore, the illustrated valve assembly 1 is directly applicable to commonly occurring, non-rectangular geometries with very good space utilization, without modification or additional seals in the area of ​​a flange connection. For this reason alone – without limiting the invention to this geometry – a pipe with a circular free cross-section, such as is found after an exhaust gas cooler in the exhaust systems of modern motor vehicles, was chosen for the above-described graphical representation of the embodiments of the invention. Reference symbol list

[0036] 1 Valve assembly 2 Flange 3 Flange 4 Valve body 5 Carrier plate as sealing partner of the valve body 4 6 Recess for guiding the valve body 4 in the carrier plate 5 / stopper position 9 7 Flow opening in the carrier plate 5, possibly distributed radially around the recess 6 8 Flow opening as recess in the stopper position 9 9 Stopper position 10 Sliding sleeve in the carrier plate 5 11 Rod of the valve body 4 12 Head of the valve body 4 / shield 13 Screw hole for a flange connection 14 Sliding sleeve as guide arranged in the stopper position 9 15 Metal bead seal 16 Metal bead seal 17 Rivet 18 Opening in the hollow rod 11 near the shield 12 19 Axial guide 20 Detent lug 21 Free end of the hollow Stem / rod 11 of the valve body 4 a) Head diameter of the valve body 4 A) Free pipe cross-sectional area b) Diameter of a single circular recess in the carrier plate 5 as flow opening h) Valve stroke

Claims

1. Valve arrangement for exhaust gas recirculation in an exhaust gas train of a motor vehicle which is driven by an internal combustion engine, a support plate (5) and a stopper position (9) having recesses corresponding to a screw hole (13) in end flanges (2, 3), characterized in that the valve arrangement (1) comprises a valve body (4) which forms a separate part and is shaped in the form of a mushroom or umbrella, which consists of an umbrella (12) and a rod (11), wherein the valve body (4) is axially guided in a gas-flow-through region in a support plate (5) and, in a closed position, rests with its screen (12) on the support plate (5), sealing off the gas-flow-through region, and has an end stop for an open position of the valve body (4), which is formed by a three-dimensionally deformed stopper layer (9) provided with at least one through-flow opening.

2. Valve arrangement according to the preceding claim, characterized in that a stopper position (9) forms the end stop for the mushroom or umbrella-shaped valve body (4) in the open position and defines a maximum valve stroke.

3. Valve arrangement according to the preceding claim, characterized in that the mushroom- or umbrella-shaped valve body (4) is guided via a rod (11) in a recess (6) of the carrier plate (5) and / or the stopper position (9).

4. Valve arrangement according to the preceding claim, characterized in that the carrier plate (5) and / or the stopper layer (9) have at least one recess (7, 8) for exhaust gases flowing through and / or a sliding bearing as a guide for the rod (11).

5. Valve arrangement according to one of the two preceding claims, characterized in that the at least one recess (7, 8) in the carrier plate (5) and the stopper layer (9) is formed congruently in the direction of flow of the exhaust gases and is aligned.

6. Valve arrangement according to one of the preceding claims 2 - 5, characterized in that the stopper layer (9) and the carrier plate (5) are connected to one another in a force-fitting, form-fitting and / or material-fitting manner.

7. Valve arrangement according to claim 2, characterized in that the stopper layer (9) and carrier plate (5) are formed as seals for the flanges (2, 3).

8. Valve arrangement according to one of the preceding claims, characterized in that a guide of the mushroom-shaped or umbrella-shaped valve body (4) is designed as a sliding bearing in the form of a sliding sleeve (10, 14).

9. Valve arrangement according to one of the preceding claims, characterized in that a guide of the mushroom- or umbrella-shaped valve body (4) is designed in that a material of the relevant sheet metal part (5, 9) which is present at the opening (7) in the carrier plate (5) is folded over and / or deep-drawn to form an axial guide (19).

10. Valve arrangement according to one of the preceding claims 6 - 9, characterized in that the valve arrangement (1) has at least one additional seal (15, 16) for the sealing function to the flanges (2, 3).

11. Valve arrangement according to the preceding claim, characterized in that the additional seal (15, 16) is designed as a metal bead seal connected to the stopper layer (9) and carrier plate (5).

12. Valve arrangement according to one of the preceding claims, characterized in that the mushroom- or umbrella-shaped valve body (4) is designed as an injection-moulded or moulded, milled or turned part which consists of a thermally resilient material.

13. Valve arrangement according to one of the preceding claims, characterized in that the mushroom- or umbrella-shaped valve body (4) is provided with a rod (11) in the form of a hollow, cylindrical stem, which has openings (18) adjacent to the umbrella (12), which are arranged distributed around a circumference of the rod (11).

14. Valve arrangement for exhaust gas recirculation in an exhaust gas train of a motor vehicle which is driven by an internal combustion engine arranged between flanges (2, 3), characterized in that the valve arrangement (1) comprises a valve body (4) which forms a separate part and is shaped in the form of a mushroom or umbrella, which consists of an umbrella (12) and a rod (11), and the rod (11) is provided in the form of a hollow, cylindrical stem, which has openings (18) adjacent to the screen (12), which are arranged distributed around a circumference of the rod (11), the valve body (4) being axially guided in a gas-flow-through region in a support plate (5) and, in a closed position, resting with its screen (12) on the support plate (5) in such a way as to seal off the gas-flow-through region, and the rod (11) has at least one latching lug (20) or a collar at a free end (21), which together with an axial guide (19) defines a maximum stroke (h) of the valve body (4).

15. Valve arrangement according to claim 14, characterized in that the carrier plate (5) is of double design and an adjacent material of the sheet metal parts (5, 5) is deep-drawn in mirror image to form an axial guide (19).