Valve device for a fuel supply system of an internal combustion engine

Abstract

Valve device (19) for a fuel supply system (1) of an internal combustion engine (2), with - a housing (20) in which a flow channel (21) for fuel is formed, - a valve seat assembly (29) which is fixed in the flow channel (21) and has a first flow channel (31) for the fuel and a first valve seat (32), - a first valve body assembly (28), comprising: ◯ a movably mounted first valve body (40) which cooperates with the first valve seat (32) to close the first flow channel (31), ◯ a spring device (41) for pre-tensioning the first valve body (40) against the first valve seat (32), ◯ a spring support assembly (42) fixed in the flow channel (21), which has a recess (45) in which the spring assembly (41) is at least partially arranged, wherein the recess (45) of the spring support assembly (42) is blind-shaped and closed on one side facing away from the valve seat assembly (29), characterized in that the spring support assembly (42) has at least one bypass channel (48) for the fuel in a region radially surrounding the recess (45), through which the fuel can flow through the spring support assembly (42) bypassing the recess (45).

Description

[0001] The invention relates to a valve device for a fuel supply system of an internal combustion engine, in particular a valve device for a high-pressure fuel pump.

[0002] From the publication US 2015 / 0078922 A1, a high-pressure fuel pump for providing pressurized fuel for an internal combustion engine is known. Fuel is conveyed via an intake side into a pressure chamber of the pump, where it is compressed by a reciprocating piston and expelled as pressurized fuel through an outlet channel. A valve device designed as a combined outlet and pressure relief valve is arranged in the outlet channel. The pressure relief valve is designed as a spring-loaded ball valve, with the spherical valve body pressed against the sealing seat by a spring. With the ever-increasing system pressure in gasoline engines with direct fuel injection, increased wear can occur in such a valve device.These signs of wear can lead to an undesirable change in the valve characteristics and, in the further course, to restrictions in the operational reliability of the high-pressure fuel pump.

[0003] DE 10 2014 207 423 A1 discloses a valve device and a high-pressure pump comprising the same. The valve device comprises a valve housing, a valve element, a pressure device, another valve element, another pressure device, and a common seat section. This valve device reduces the number of manufacturing steps.

[0004] A valve device is known from DE 10 2011 005 487 A1. It is an outlet valve of a high-pressure fuel pump of an internal combustion engine, comprising a housing, a flow channel, and a plate-shaped, movable valve body arranged in the flow channel. The valve body has a sealing section that, when the valve device is closed, partially abuts against a sealing seat on the housing. Adjacent sections of the sealing section and the sealing seat form a contact area. When the valve device is closed, a wedge-shaped gap is temporarily present adjacent to the contact area between the sealing section and the sealing seat.

[0005] DE 10 2012 207 923 A1 discloses a valve device. In this device, a valve seat has an inner passage and an outer passage. An intake valve component has first passages and a first protrusion portion that guides fuel flowing from a pressure chamber at the time of valve opening to the first passages.

[0006] A fuel pump for a direct injection system is known from US 10,094,346 B1. This pump has a pump chamber, a piston, an intake duct, a

[0007] DE 10 2007 016 134 A1 discloses a high-pressure fuel pump with a delivery chamber and a high-pressure outlet. A pressure relief valve with a pressure-differential-actuated element is provided, which can open from the high-pressure outlet to the delivery chamber. Viewed from the valve seat of the pressure relief valve, a throttle device is arranged on its high-pressure side. The free cross-section of the throttle device is approximately equal to the maximum opening cross-section of the pressure relief valve.

[0008] DE 20 2018 200 612 A1 shows a high-pressure connection for a high-pressure fuel pump with an outlet valve and a pressure relief valve.

[0009] It is therefore the object of the present invention to provide a valve device and a high-pressure fuel pump which are characterized by higher wear resistance and higher operational reliability.

[0010] This object is achieved by the valve device and the high-pressure fuel pump according to the independent claims.

[0011] A valve device for a fuel supply system of an internal combustion engine according to claim 1 has a housing in which a flow channel for fuel is formed. A valve seat device is fixed in the flow channel, which has a first flow channel for the fuel and a first valve seat. The valve device further comprises a first valve body device with a movably mounted first valve body, which cooperates with the first valve seat to open and close a channel opening of the first flow channel. The valve body device further comprises a first spring device for prestressing the first valve body against the first valve seat and a spring support device fixed in the flow channel, which has a recess in which the first spring device is at least partially, advantageously completely, arranged.The recess of the spring support device is designed as a blind hole and is closed on a side facing away from or opposite the valve seat devices. The spring support device further comprises at least one bypass channel or bypass channel in a radial region surrounding the recess.

[0012] The invention is based on the finding that wear and operational reliability of such a valve device can be improved by protecting the spring devices, valve body, and valve seats from direct fuel flow. This is because the first valve body and the first spring device together form an oscillatory system, which is excited to high-frequency micro-oscillations when exposed to direct fuel flow. This results in gradual wear during operation of the high-pressure fuel pump.

[0013] In the valve device according to the invention, a spring support device with a blind hole-shaped recess for receiving the first spring device is therefore provided, wherein the recess is open in the direction of the valve seat device and closed on a side facing away from or opposite the valve seat device. The blind hole-shaped recess is closed on one side and is not directly flowed through by fuel during operation of the high-pressure fuel pump. The recess thus forms a flow-calmed receiving space for the spring device. The fuel is guided past the recess via the at least one bypass channel, which is formed in a region of the spring support device radially surrounding the recess. In this way, the first spring device and the first valve body are shielded from a direct, axial flow of fuel.Vibration excitation due to flow forces can be minimized in this way, which greatly reduces wear on the valve.

[0014] In one embodiment of the valve device according to claim 2, the blind hole-shaped recess has a bottom, wherein a convex contour is formed on a side of the bottom facing away from the valve seat device.

[0015] The convex contour acts as a flow divider or guide contour for fuel. The fuel flow striking the bottom of the recess is guided by the contour in a streamlined manner to the at least one bypass channel. In this way, the flow resistance of the valve device can be significantly reduced. The convex contour can be arranged centrally and have the shape of a rounded curvature or a point. Advantageously, the contour extends radially to the at least one bypass channel.

[0016] In one embodiment of the valve device according to claim 3, the spring support device projects out of the flow channel with an end section, wherein an annular groove is formed on the outer circumference of the end section.

[0017] This design proves particularly advantageous for mounting the valve device on an outlet port of a high-pressure fuel pump using a welding process. This allows the valve device to be inserted into the outlet port of the high-pressure fuel pump with the end section of the spring support device facing forward, and the housing of the valve seat device can be welded to the flange of the pump housing. Weld beads or other waste products created during the welding process collect in the annular groove. This prevents the ingress of disruptive particles into the high-pressure fuel pump or the valve assembly.

[0018] In an embodiment of the valve device according to claim 4, the spring support device has a plurality of bypass channels which are distributed circumferentially in the area radially surrounding the recess.

[0019] In this embodiment, the blind-hole-shaped recess is advantageously formed radially centrally on the spring support device. Several bypass channels are provided, which radially surround the cup-shaped recess and are advantageously evenly distributed in the circumferential direction. This allows the flow resistance of the spring support device for the fuel to be significantly reduced and the overall throughput through the valve device to be increased.

[0020] In one embodiment of the valve device according to claim 5, the first passage channel is formed as a central bore on the valve seat device. The spring device has a first spring and a guide body for the first valve body, coupled to the first spring. The first spring is supported on a bottom of the recess of the spring support device relative to the housing and presses the first valve body against the first valve seat of the valve seat device by means of the guide body. The guide body has an annular groove on a side facing the valve seat device, which is designed and arranged such that fuel escaping from the channel opening of the first flow channel strikes the guide body at the position of the groove.

[0021] In a further embodiment of the valve device according to claim 6, the first valve body is designed as a ball, wherein the guide body has a centrally arranged receiving recess for receiving the first valve body on the side facing the valve seat device. The annular groove radially surrounds the receiving recess and has a diameter that is larger than that of the valve body.

[0022] A very compact design of the valve device requires a small diameter for the first valve body and a small coil diameter of the associated first spring. This is accompanied by unfavorable opening characteristics of the valve and can result in multiple, high-frequency opening and closing processes, which greatly increases wear. To counteract this effect, the guide body has an annular groove, the geometric design of which ensures that a fuel flow through the valve in the direction of the guide body largely impacts the guide body at the position of the groove. The fuel penetrates the groove at high speed, experiences a strong change in momentum there, and thus exerts a force on the guide body and the spring. This force counteracts the spring force and thus stabilizes the opening position of the valve body.This compensates for the valve's geometrically determined, unfavorable opening characteristics. Undesired, high-frequency opening and closing cycles and the associated increased wear are prevented.

[0023] In an advantageous embodiment of the valve device according to claim 7, the groove has a maximum depth between 0.1 and 3 millimeters, a maximum width between 0.1 and 5 millimeters, a transition angle between the groove base and the lateral flank (wall) between 60 and 150 degrees and a maximum diameter between 0.5 and 5 millimeters.

[0024] In an advantageous embodiment of the valve device according to claim 8, further flow channels are formed on the valve seat device, which radially surround the first flow channel. A further valve seat is formed on a side surface of the valve seat device opposite the first valve seat (i.e. facing away from the first valve body device). The further valve seat has two concentric, annular projections which protrude from the side surface. The channel openings of the further flow channels are arranged radially between the projections. A further valve body device with a movably mounted further valve body with a flat sealing surface is provided in the flow channel. This further valve body comes into sealing contact with the projections of the further valve seat to close the channel openings of the further flow channels.

[0025] The radially outer projection does not extend radially to an outer diameter of the valve seat device, ie the outer diameter of the radially outer projection is smaller than the outer diameter of the valve seat device.

[0026] In an embodiment of the valve device according to claim 9, the annular projections each have a flat sealing surface.

[0027] In an embodiment of the valve device according to claim 10, the annular projections each have a spherical sealing surface.

[0028] In one embodiment of the valve device according to claim 11, the projections on the spherical sealing surfaces have a radius of curvature between 0.5 and 10 millimeters.

[0029] At very high system pressures, even the smallest deviations in the sealing surfaces or sealing band widths on the plate valve have a significant impact on the hydraulic surface ratios and thus on the closing behavior, the opening pressure and the noise development of the valve. In order to minimize the influence of manufacturing tolerances on the hydraulic surface ratios on the valve as much as possible and to reduce the opening pressure, the effective sealing band width on the valve must be reduced as much as possible. Therefore, two narrow, concentric, annular projections (steps or webs) are formed on the side surface of the valve seat device facing the additional valve body device, which form the additional valve seat. This significantly reduces the effective sealing surface (contact area between the additional valve body and the additional valve seat) compared to a full-surface valve seat.An even further reduction in sealing band widths is achieved by providing the projections or shoulders with a spherical sealing surface. In this case, the sealing surfaces of the projections are not flat but curved toward the other valve body. The sealing surfaces have a curved contour or radius. This allows the contact surface between the projections and the flat surface of the other valve body to be approximated to a line. In this way, the influence of manufacturing tolerances on the hydraulic surface ratios and the piston chamber pressure can be noticeably reduced, thus significantly increasing the reliability and operating behavior of the valve device, especially at very high pressures.

[0030] In one embodiment of the valve device according to claim 12, the annular projections have a maximum width of 0.1 to 2 millimeters, with the radially outer projection having an inner diameter of between 5 and 15 millimeters and the radially inner projection having an inner diameter of between 0.5 and 4 millimeters. The maximum width of the projections corresponds to the maximum extension or extent of the respective projection in the radial direction.

[0031] A high-pressure fuel pump for an internal combustion engine according to claim 13 comprises a pump housing, a pressurizing means for the fuel provided therein, and a high-pressure outlet channel formed in the pump housing for expelling the pressurized fuel. Furthermore, the high-pressure fuel pump comprises a valve device according to one of claims 8 to 10, which is coupled to the high-pressure outlet channel so that the fuel expelled during operation of the pressurizing means flows in a conveying direction through the flow channel of the valve device. The first valve body device, the valve seat device, and the further valve body device are arranged one behind the other in the conveying direction in the flow channel.The first valve body device and the first valve seat together function as a safety valve, which opens when a limit value of the fuel pressure in the feed direction downstream of the valve device is exceeded, thus allowing fuel to flow back against the feed direction through the first flow channel, and which is otherwise closed. The further valve body device and the further valve seat together function as an outlet valve for the fuel, which allows fuel to flow through the further flow channels in the feed direction and prevents fuel from flowing back against the feed direction through the further flow channels.

[0032] With regard to the advantages of this high-pressure fuel pump, reference is made to the statements relating to the preceding patent claims, which apply here in an analogous manner.

[0033] The invention is explained in more detail below using an exemplary embodiment with reference to the accompanying figures. The figures show: Fig. 1 is a schematic representation of a fuel supply system for an internal combustion engine; Fig. 2 a schematic representation of a valve device; Fig. 3 a schematic representation of a housing of the valve device; Fig. 4A to 4F are schematic representations of a valve seat device; Fig. 5A to 5D are schematic representations of a spring support device of the valve device; Fig. 6A to 6C are schematic representations of a guide body;

[0034] In Fig. 1 schematically illustrates a fuel supply system 1 for an internal combustion engine 2. The fuel supply system 1 illustrated here comprises a fuel reservoir 3, a low-pressure fuel pump 4, a high-pressure fuel pump 5, a fuel pressure accumulator 6 (common rail), and several injection valves 7.

[0035] A pressurizing means 9 for the fuel is provided in a pump housing 8 of the high-pressure fuel pump 5. For this purpose, a cylindrical recess 10 is formed in the pump housing 8, in which a piston 11 is displaceably mounted. The piston 11 is coupled to a drive means 12, which causes the piston 11 to perform periodic stroke movements (double arrow in Fig. 1). A section of the cylindrical recess 10 functions as the working chamber 13 of the pressurizing means 9. The reciprocating movement of the piston 11 alternately increases and decreases the volume of the working chamber 13. The working chamber 13 is fluidly connected to the low-pressure fuel pump 4 via a low-pressure inlet channel 14 formed in the pump housing 8 and a fuel line 15. When the low-pressure fuel pump 4 is in operation, fuel is pumped from the reservoir 3 into the working chamber 13 via the fuel line 15 and the low-pressure inlet channel 14. The high-pressure fuel pump 5 furthermore has an advantageously electrically operated inlet valve 16, which in particular controls the inflow of fuel into the working chamber 13 and only allows a backflow of fuel from the working chamber 13 under certain operating conditions.

[0036] The working chamber 13 is further fluidically connected to the fuel pressure accumulator 6 via a high-pressure outlet channel 17 formed in the pump housing 8 and a further fuel line 18. The high-pressure fuel pump 5 further comprises a valve device 19, which is fluidically coupled to the high-pressure outlet channel 17 and is attached to the pump housing 8. The valve device 19 functions as an outlet valve and safety valve.

[0037] During operation of the fuel supply system 1, fuel is pumped from the fuel tank 3 to the high-pressure fuel pump 5 by means of the low-pressure fuel pump 4. The fuel is pumped into the working chamber 13 via the open inlet valve 16 and the low-pressure inlet channel 14, where it is compressed by the pressurizing agent 9. The compressed or pressurized fuel is expelled from the working chamber 13 in a delivery direction F via the high-pressure outlet channel 17 and the valve device 19. The expelled fuel flows via the further fuel line 18 in the delivery direction F to the fuel pressure accumulator 6. The injection valves 7, which are advantageously electrically controlled and connected to the fuel pressure accumulator 6, meter the fuel supply to the combustion chambers of the internal combustion engine 2.

[0038] In Fig. 2 shows an embodiment of the valve device 19. The valve device 19 has a housing 20, which is Fig. 3 is shown in detail. The housing 20 is preferably made of a solid metallic cylinder with a circular cross-section. A flow channel 21 with an inlet opening 22 and an outlet opening 202 is formed in the housing 20. The flow channel 21 has sections 23, 24, 25 and 26 with different diameters (see Fig. 3). These sections 23, 24, 25, 26 serve to accommodate further components of the valve device 19, which are described below. Fig. 3 the rotation axis R of the housing is shown in dashed lines.

[0039] “Axial” x means hereinafter directed parallel to the rotation axis R. “Radial” y means hereinafter directed perpendicular to the rotation axis

[0040] With reference to Fig. 2, the valve device 19 is attached to the housing 8 of the high-pressure fuel pump 5 and fluidly coupled to the high-pressure outlet channel 17. The housing 20 of the valve device 19 is attached to a connecting flange 27 of the high-pressure outlet channel 17 on the inlet opening 22 side such that the fuel expelled from the high-pressure fuel pump 5 via the high-pressure outlet channel 17 flows in the conveying direction F through the flow channel 21. The connection between the valve device 19 and the high-pressure fuel pump 5 is designed to be tight, so that no fuel escapes at the connection point. Advantageously, the housing 21 is attached to the pump housing 8 by means of a welded connection. Alternatively or additionally, positive fastening methods such as crimping, pressing, or screwing are also conceivable.

[0041] Starting from the inlet opening 22, a first valve body device 28, a valve seat device 29 and a further valve body device 30 are arranged one behind the other in the flow channel 21 in the conveying direction F (i.e. in the axial direction x).

[0042] The valve seat assembly 29 is shown in section 24 (see Fig. 3) of the flow channel 21 by means of a press connection. Alternatively or additionally, form-fitting or material-locking fastening methods are possible (crimping, welding, screwing). An advantageous embodiment of the valve seat device 29 is shown in the Fig. 4A to 4F are shown as examples. Fig. 4A, Fig. 4B and Fig. 4C shows side views of the valve seat assembly. Fig. 4D is a sectional view in the direction of the section line AA of the Fig. 4A. Fig. 4E is a sectional view along section line BB of the Fig. 4A. Fig. Figure 4F is an enlarged view of detail C in Fig. 4D.

[0043] The valve seat device 29 is advantageously made of a solid metal cylinder with a circular cross-section. It has a first flow channel 31, which is designed as a central bore. The valve seat device 29 further has a first valve seat 32, which is formed on a channel opening 33 of the first flow channel 31 facing the first valve body device 28 (see Fig. 2). The valve seat assembly 29 has a plurality of additional flow channels 34, which radially surround the first flow channel 31 in a ring shape. The additional flow channels 34 are evenly spaced from one another in a circular manner.

[0044] On a side of the valve seat device 29 opposite the first valve seat 32, ie on the side of the valve seat device facing the further valve body device 30 (see Fig. 2) a further valve seat 35 is formed, which is formed by two concentric, circular projections 36, 37. The channel openings 38 of the further flow channels 34 facing the further valve body device 30 are arranged in the radial direction between the two projections 36, 37. The projections 36, 37 are designed such that they protrude from the side surface of the valve seat device 29 facing the further valve body device 30 in the axial direction by a predetermined amount h (see Fig. 4A and Fig. 4D), which should be at least 0.05 mm, in the direction of the further valve body device 30. The radially outer projection 36 does not extend in the radial direction to the radial edge (outer diameter) of the valve seat device 29. It has an outer diameter Dva ( Fig. 4F) which is smaller than the outer diameter Dmax of the valve seat device 29 ( Fig. 4E).

[0045] Furthermore, the valve seat device 29 is designed such that the channel openings 38 of the further flow channels 34 arranged between the two annular projections 36, 37 are fluidically connected via an annular channel 39. The annular channel 39 is formed by the two annular projections (36, 37).

[0046] As in Fig. 4F, the annular projections 36, 37 are advantageously spherical on their respective sealing surfaces (axial end surfaces), ie they are axially curved and have a radiused cross-section or a spherical contour. Due to the spherical shape, the effective sealing bands between the projections 36, 37 and a flat sealing surface of the further valve body 56 (see Fig. 2) is reduced to such an extent that virtually two sealing lines are created. This allows production-related tolerances regarding the hydraulically acting surfaces on the valve to be largely minimized, resulting in reproducible valve characteristics, lower component stress, and reduced noise. Furthermore, pressure peaks in the working chamber 13 can be reduced.

[0047] Advantageously, the spherically designed projections or shoulders 36, 37 have a maximum width Bs of 0.1 to 2 millimeters and, at their axial end surfaces (sealing surfaces), an axial radius of curvature Rs of between 0.5 and 10 millimeters. The radially outer projection 36 has an inner diameter Dsa of between 5 and 15 millimeters, and the radially inner projection has a diameter Dsi of between 0.5 and 4 millimeters.

[0048] The projections 36, 37 can alternatively also have flat sealing surfaces, i.e., be designed without a spherical contour. This embodiment offers advantages in terms of manufacturing costs.

[0049] As in Fig. As can be seen in Figure 2, the first valve body device 28 comprises a movably mounted first valve body 40 in the form of a ball, a first spring device 41 for preloading the first valve body 40, and a spring support device 42. The spring device 41 comprises a first spring 43, preferably a helical spring, and a guide body 44 coupled to the first spring 43, wherein the first spring 43 transmits its spring force to the first valve body 40 with the aid of the guide body 44.

[0050] In the Fig. 5A to 5D show an advantageous embodiment of the spring support device 42. Fig. 5A is a side view. Fig. Figure 5B is a sectional view along section line BB in Fig. 5A. Fig. Figure 5C is a sectional view along the section line CC in Fig. 5A. Fig. 5D is a sectional view along the section line AA in Fig. 5A. The spring support device 42 is advantageously made from a solid metallic cylinder with a circular cross-section or by a sintering process and is fastened in section 23 of the flow channel 21 by means of a press connection (alternatively or additionally by a form-fitting or material-fitting connection). A blind hole-shaped recess 45 is formed in the spring support device 42. The recess 45 is positioned in the flow channel 21 such that it is open in the direction of the valve seat device 29 and closed in the direction of the inlet opening 22. The open side 46 of the recess 45 therefore points in the conveying direction F, whereas the closed part, i.e. the bottom 47, of the recess 45 faces the inlet opening 22.

[0051] The first spring device 41 is at least partially arranged in the blind hole-shaped recess 45, which is closed on one side. Fig. 2, the first spring 43 and the guide body 44 are arranged almost completely in the recess 45. The first spring 43 is supported on the bottom 47 of the recess 45 opposite the housing 20 (see Fig. 2).

[0052] In an area radially surrounding the recess 45, the spring support device 42 has a plurality of bypass channels 48 or flow-around channels. Advantageously, the bypass channels 48 surround the recess 45 in a ring-shaped manner, i.e., they are at the same radial distance from the recess 45 and are advantageously also evenly spaced circumferentially. Fuel can flow through the spring support device 42 via the bypass channels 48, bypassing the recess 45, which is closed on one side.

[0053] A convex contour 49 is formed on a side of the bottom of the spring support device 42 facing away from the valve seat device 29 (ie on a side facing the inlet opening 22). The convex contour 49 can be designed as a round curvature or tapered (see Fig. 5A). The convex contour 49 curves axially in the direction of the inlet opening 22 of the housing 20 of the valve device 19. The contour 49 is advantageously arranged radially centrally and extends in the region of the base 47 over the entire area within the ring of bypass channels 48. A large part of the fuel coming from the high-pressure outlet channel 17 impacts at high speed onto the base 47 of the spring carrier device 42 (see Fig. 2). The convex contour 49 acts as a flow divider or guide contour for the fuel, which noticeably reduces the flow resistance of the spring support device 42.

[0054] At an end portion of the spring support device 42 remote from the valve seat device 29, i.e., at an end portion near the inlet opening 22, a circumferential annular groove 50 is formed on its outer circumference. The bottom 47 of the recess 45 with the convex contour 49 is also located at this end portion.

[0055] At the Fig. In the advantageous embodiment of the valve device 19 shown in Figure 2, the spring support device 42 protrudes with the end section on the side of the inlet opening 22 from the flow channel 21 to such an extent that at least the bottom 47 and the annular groove 50 are located outside the flow channel 21. Advantageously, the annular groove 50 is located directly at the inlet to the flow channel 21. The annular groove 50 serves to absorb weld beads or other undesirable by-products that may arise during the welding process for attaching the valve seat device 19 to the pump housing 8.

[0056] In this way, leaks and the penetration of particles into the flow channel 21 can be avoided.

[0057] In the Fig. 6A to 6C show the guide body 44 of the valve body device 28 in detail. The guide body 44 is advantageously made of a solid metal cylinder. The guide body 44 has a stamp-like shape, with an elongated, cylindrical guide section 52 and a short, flat holding section 53. The diameter of the guide body 44 at the holding section 53 is larger than at the guide section 52.

[0058] With reference to Fig. 2, the guide body 44 with its guide section 53 dips into the first spring 43 and is encompassed there by the first spring 43. The holding section 53 of the guide body 44 acts as an axial stop due to its larger diameter and forms the force application surface for the first spring 43. The first spring 43 is thus supported at one end on the base 47 of the spring support device 42 and at the other end on the holding section 53 of the guide body 44. The first spring 43 is compressed and therefore exerts a force on the first valve body 40 via the guide body 44, which force presses the first valve body 40 against the first valve seat 32, whereby the first flow channel 31 is closed.

[0059] In Fig. 2 in conjunction with Fig. 6B shows that the guide body 44 has, on a side of the holding section 53 facing the valve seat device 28, a centrally arranged receiving recess 54 for receiving the spherical first valve body 40. This holds the first valve body 40 and stabilizes it in its radial position. The guide body 44 also has, on the side of the holding section 53 facing the valve seat device 29, an annular groove 55 that radially surrounds the receiving recess 54. The diameter Dn of the groove is larger than the diameter Da of the receiving recess and larger than the diameter of the spherical first valve body 40 (not shown).

[0060] If the pressure in the fuel pressure accumulator 6 rises above a certain critical limit value, the pressure force acting on the spherical first valve body 40 is greater than the spring force FF acting on the first valve body 40 by the first spring 43. As a result, the first valve body 40 lifts off the first valve seat 32. Fuel flows from the fuel pressure accumulator 6 through the central first flow channel 31 of the valve seat device 28. Due to the centrally arranged first valve body 40, a hollow cone-like flow pattern results at the outlet of the first flow channel 31 in the direction of the guide body 44. The diameter D of the annular groove 55 formed on the guide body is dimensioned such that the fuel escaping from the channel opening 33 of the first flow channel 31 strikes the guide body 44 at the position of the groove 55.The fuel flow enters the groove 55, bounces off the groove base 551, experiences a change in momentum there, and flows sideways out of the groove 55 again. The change in momentum that the fuel experiences due to entering the groove 55 is significantly greater than if the fuel were merely to hit a flat surface. As a result, the flow force, which is directed against the spring force FF of the first spring 43, is significantly increased, which stabilizes the guide body 44 and the first valve body 40 in their open position. In this way, the opening characteristics can be significantly improved. In particular, vibrations of the first spring 43 and repeated closing and opening processes at the first valve seat 32 can be significantly reduced, which has a positive effect on wear behavior.

[0061] For the annular groove 55, it has proven advantageous if the maximum depth Tn is between 0.1 and 3 millimeters (distance from the surface to the groove base 551) and the maximum width Bn (radial width) is between 0.1 and 5 millimeters. The transition angle Rn between the groove base 551 and the lateral boundary wall of the groove 55 (flank) is between 60 and 150 degrees. The annular groove 55 advantageously has an inner diameter Dn between 0.5 and 5 millimeters.

[0062] With reference to Fig. 2, the further valve body device 30 has a further valve body 56, a further spring 57 and a further spring support device 58. The further spring support device 58 is advantageously fixed in section 26 of the flow channel 21 of the housing 20 by means of a press connection, alternatively or additionally by a form-fitting or material connection. The further spring 57 is designed as a helical spring and is supported at one end on the further valve body 56 and at the opposite end on the further spring support device 58. The further spring 57 is compressed and presses the movably mounted further valve body 56 against the further valve seat 35 of the valve seat device 29. The further valve body 56 has a flat sealing surface on a side facing the valve seat device 29 or the further valve seat 35, which interacts with the further valve seat.In order to close the further flow channels 34 formed in the valve seat device 29, the further valve body 56 comes into sealing contact with the two concentric, annular webs 36, 37 of the further valve seat 35 on its flat sealing surface (see . Fig. 2 and Fig. 4D). The further valve body 56 and the further spring support device 58 each have central bores 59, 60, which fluidically communicate with or are fluidically coupled to the centrally arranged first flow channel 31 of the valve seat device 29. Via these bores 59, 60 and the first flow channel 31, there is a permanent fluidic connection between the fuel pressure accumulator 6 and the first valve seat 32 of the valve seat device 29.

[0063] The valve device 19 has a dual function: The first valve body device 28 is assigned to the first valve seat 32 of the valve seat arrangement 29. The first valve body device 28 and the valve seat arrangement are together designed as a safety valve which discharges into the working chamber 13. Due to the first flow channel 31 formed in the valve seat arrangement 29 and the central bores 59, 60 in the further valve body 56 and the further spring carrier device 58, there is an open, fluidic connection between the first valve seat 32 and the fuel pressure accumulator 6. As a result, essentially the same fuel pressure is applied to the first valve seat 32 and the first valve body 40 as prevails in the fuel pressure accumulator. During normal operation, i.e. when the pressure in the fuel pressure accumulator 6 does not exceed a permissible limit, the spring force FF acting on the first valve body 40 is greater than the counteracting pressure force of the fuel.During normal operation of the fuel supply system 1, the safety valve is therefore closed. The first valve body 40 bears sealingly against the first valve seat 32, closes the channel opening 33 of the first flow channel 31, and thus prevents a backflow of fuel from the fuel pressure accumulator 6 against the conveying direction F through the first flow channel 31 in the direction of the high-pressure fuel pump 5. During emergency operation of the fuel supply system, in which the pressure in the fuel pressure accumulator 6 exceeds the permissible limit, the pressure force on the first valve body 40 exceeds the opposing spring force FF of the first spring 43, whereby the first valve body 40 is lifted from the first valve seat 32 and opens the channel opening 33 of the first flow channel 31.This allows fuel to flow back from the fuel pressure accumulator 6, counter to the flow direction F, via the first flow channel 31 and the bypass channels 48 of the first spring support device 42 toward the working chamber 13 of the high-pressure fuel pump 5. This prevents overpressure in the fuel pressure accumulator 6 and damage.

[0064] The further valve body device 30 is assigned to the further valve seat 35 of the valve seat assembly 29. The further valve body device 30 and the valve seat assembly 29 with its further valve seat 35 are designed as an outlet valve. Its primary function, during normal operation of the fuel supply system 1, is to prevent the backflow of fuel against the delivery direction and to only allow fuel flow from the high-pressure fuel pump 5 to the fuel pressure accumulator 6. During normal operation of the fuel supply system 1, the safety valve is closed. The first valve body 40 bears in a sealing manner against the first valve seat and closes the channel opening 33 of the first flow channel 31. During normal operation, the fuel flow through the valve device 19 is therefore dependent on the state of the outlet valve.The further valve body 56 is pressed in the direction of the further valve seat 35 by the spring force of the further spring 57 and by the pressure force of the fuel on the side of the fuel pressure accumulator 6. On the other hand, the further valve body 56 is fluidly connected to the working chamber 13 of the high-pressure fuel pump 5 via the bypass channels 48 of the first spring carrier device 42 and the further flow channels 34 of the valve seat device 29. A hydraulic pressure therefore acts on the side of the high-pressure fuel pump 5, which pushes the further valve body 56 away from the further valve seat 35, i.e. pushes the outlet valve into the open position. The outlet valve is designed such that it is open during normal operation of the fuel supply system 1 and allows fuel to flow in the delivery direction F.The outlet valve closes only if the pressure conditions on the side of the fuel pressure accumulator 6 are so predominant that an unwanted backflow would occur against the delivery direction F. This is particularly the case when the high-pressure fuel pump 5 is switched off or is in the intake phase, but at the same time the pressure in the fuel pressure accumulator 6 is still so high that an unwanted backflow would occur.

Claims

[1] Valve device (19) for a fuel supply system (1) of an internal combustion engine (2), with - a housing (20) in which a flow channel (21) for fuel is formed, - a valve seat device (29) which is fixed in the flow channel (21) and has a first flow channel (31) for the fuel and a first valve seat (32), - a first valve body device (28), comprising: ◯ a movably mounted first valve body (40) which cooperates with the first valve seat (32) to close the first flow channel (31), ◯ a spring device (41) for prestressing the first valve body (40) against the first valve seat (32), ◯ a spring support device (42) fixed in the flow channel (21), which has a recess (45) in which the spring device (41) is at least partially arranged, wherein the recess (45) of the spring support device (42) is designed in the shape of a blind hole and is closed on a side facing away from the valve seat device (29) characterized by that the spring support device (42) has at least one bypass channel (48) for the fuel in a region radially surrounding the recess (45), via which the fuel can flow through the spring support device (42) bypassing the recess (45) [2] Valve device (19) according to claim 1, wherein the blind hole-shaped recess (45) has a bottom (47) and wherein a convex contour (49) is formed on a side of the bottom (47) facing away from the valve seat device (29). [3] Valve device (19) according to one of claims 1 to 2, wherein the spring support device (42) projects with an end portion out of the flow channel (21) and an annular groove (50) is formed on the outer circumference of the end portion. [4] Valve device (19) according to one of claims 1 to 3, wherein the spring support device (42) has a plurality of bypass channels (48) which are circumferentially distributed in the region radially surrounding the recess (45). [5] Valve device (19) according to one of claims 1 to 4, wherein - the first flow channel (31) is formed as a central bore on the valve seat device (29), - the spring device (41) has a first spring (43) and a guide body (44) coupled to the first spring (43) for the first valve body (40), wherein the first spring (43) is supported on a bottom (47) of the recess (45) of the spring support device (42) and presses the first valve body (40) against the first valve seat (32) of the valve seat device (29) by means of the guide body (44), - the guide body (44) has an annular groove (55) on a side facing the valve seat device (29), which groove is designed such that fuel emerging from the channel opening (33) of the first flow channel (31) strikes the guide body (44) at the position of the groove (55). [6] Valve device (19) according to claim 5, wherein the first valve body (40) is designed as a ball, and wherein the guide body (44) has a centrally arranged receiving recess (54) for receiving the valve body (40) on the side facing the valve seat device (29), and wherein the annular groove (55) radially surrounds the receiving recess (54) and has a diameter (Dn) which is larger than that of the valve body (40). [7] Valve device (19) according to one of claims 5 to 6, wherein the groove has a maximum depth (Tn) between 0.1 to 3 millimeters, a maximum width (Bn) between 0.1 to 5 millimeters, a transition angle (Rn) between a groove base (551) and a lateral flank of the groove (55) between 60 to 150 degrees and a maximum diameter (Dn) between 0.5 and 5 millimeters. [8] Valve device (19) according to one of claims 1 to 7, wherein - further flow channels (34) are formed on the valve seat device (29) which radially surround the first flow channel (31), - on a side of the valve seat device (29) opposite the first valve seat (32), a further valve seat (35) is formed, which has two concentric, annular projections (36, 37) which protrude from the valve seat device (29), wherein the further flow channels (34) are arranged radially between the annular projections (36, 37), - a further valve body device (30) with a movably mounted further valve body (56) with a flat sealing surface is provided in the flow channel (21), which comes into contact with the projections (36, 37) of the further valve seat (35) to close the further flow channels (34). [9] Valve device (19) according to claim 8, wherein the annular projections (36, 37) each have flat sealing surfaces. [10] Valve device (19) according to claim 8, wherein the annular projections (36, 37) each have spherical sealing surfaces. [11] Valve device (19) according to claim 10, wherein the projections (36, 37) on the respective sealing surfaces have a radius of curvature (Rs) between 0.5 and 10 millimeters. [12] Valve device (19) according to one of claims 8 to 11, wherein the annular projections (36, 37) each have a maximum width (Bs) of 0.1 to 2 millimeters, and wherein the radially outer projection (36) has an inner diameter (Dsa) of between 5 to 15 millimeters and the radially inner projection (37) has an inner diameter (Dsi) of between 0.5 and 4 millimeters. [13] High-pressure fuel pump (5) for an internal combustion engine (2), with - a pump housing (8), - a pressurising means (9) for the fuel provided in the pump housing (8), - a high-pressure outlet channel (17) for discharging pressurized fuel, - a valve device (19) according to one of claims 8 to 12, which is coupled to the high-pressure outlet channel (17) in such a way that the fuel ejected during operation of the pressurizing means (9) flows in a conveying direction (F) through the flow channel (21) of the valve device (19), wherein the first valve body device (28), the valve seat device (29) and the further valve body device (30) are arranged one behind the other in the flow channel (21) in the conveying direction (F), wherein the first valve body device (28) and the valve seat device (29) together function as a safety valve which opens when a limit value of the fuel pressure in the conveying direction (F) downstream of the valve seat device (29) is exceeded and which is otherwise closed, and wherein the further valve body device (30) and the valve seat device (29) together function as an outlet valve for the fuel.

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