Fuel high-pressure pump

Abstract

The invention relates to a fuel high-pressure pump (10) with a pressure-limiting valve (22) which fluidically connects a high-pressure region (29) with a low-pressure region (28) and opens toward the low-pressure region (28), wherein the pressure-limiting valve (22) is arranged in a pressure-limiting valve bore (22a) which is configured as a through-hole through the pump body (12a) and which extends from a damping region (28a) to a stepped chamber (28d) and is closed on the side pointing toward the damping region (28a) by a press-in closure (55, 57), wherein the pressure-limiting valve bore (22) is embodied as a stepped bore, comprising a first section (22.1) with a larger diameter and a second section (22.3) with a smaller diameter, and an annular step (22.2) is formed between the first section (22.1) and the second section (22.3), wherein the pressure-limiting valve (22) has a valve seat body (38) which is pressed into the pressure-limiting valve bore (22), wherein the pressure-limiting valve (22) has a valve element (44) which is pressed in the closing direction by a holding element (46) which is pressed in the closing direction by a helical spring (52) which is supported on the annular step (22.2).

Description

Background Technology

[0001] According to prior art, such as the applicant's DE 10 2018 221 702 A1, a high-pressure fuel pump is known, which has an inlet for supplying fuel, an outlet for discharging compressed fuel, a pump housing, a delivery chamber disposed in the pump housing, a pump piston movable in the pump housing in a longitudinal direction and defining the delivery chamber, an inlet valve disposed between the inlet and the delivery chamber and opening toward the delivery chamber, an outlet valve disposed between the delivery chamber and the outlet and opening away from the delivery chamber, a high-pressure region fluidly extending between the outlet valve and the outlet, a low-pressure region fluidly extending between the inlet and the inlet valve, and a pressure limiting valve that fluidly connects the high-pressure region and the low-pressure region and opens toward the low-pressure region such that when the pressure difference between the fuel in the high-pressure region and the fuel in the low-pressure region exceeds the opening pressure, fuel flows from the high-pressure region to the low-pressure region.

[0002] The pump disclosed in the prior art described at the beginning is further provided with a pump piston constructed as a stepped piston, comprising a first section pointing towards the delivery chamber and having a larger diameter and a second section having a smaller diameter and pointing away from the delivery chamber, wherein a high-pressure seal is arranged between the first section and the pump housing, the pump piston is movable within the high-pressure seal and the high-pressure seal separates the delivery chamber from the low-pressure region, wherein a low-pressure seal is arranged between the second section and a seal carrier fixed to the pump housing, the low-pressure seal separating the low-pressure region from the space outside the fuel high-pressure pump, wherein the stepped chamber of the low-pressure region is located between the seal carrier and the pump housing, wherein a pressure relief valve fluidly connects the stepped chamber of the high-pressure region and the stepped chamber of the low-pressure region and opens toward the stepped chamber, such that when the pressure difference between the fuel in the high-pressure region and the fuel in the low-pressure region exceeds the opening pressure, fuel flows out from the high-pressure region into the stepped chamber, wherein the pump housing has a pump body and a pump cover connected to each other, wherein a vibration damping region belonging to the low-pressure region is defined by the pump body and the pump cover, and at least one diaphragm vibration damper is arranged in the vibration damping region.

[0003] The pump disclosed in the prior art described at the beginning is further provided with a pressure relief valve having a valve seat body pressed into a pressure relief valve orifice, on which a conical valve seat is formed, wherein the pressure relief valve has a valve element having a spherical shape and sealingly abutting against the valve seat, wherein the valve element is pressed toward the closing direction by a retaining element, wherein the retaining element is pressed toward the closing direction by a helical spring.

[0004] The pump disclosed in the prior art described at the beginning is further provided with a pressure relief valve arranged in a pressure relief valve orifice constructed as a blind hole of the pump body, the pressure relief valve orifice extending from the stepped chamber and supported by a helical spring on a portion that is separately pressed into the pressure relief valve orifice. Summary of the Invention

[0005] This invention stems from the desire to make the configuration of a high-pressure fuel pump simple and efficient to manufacture.

[0006] Here, implementing the pressure relief valve orifice as a blind orifice extending from the stepped chamber of the pump body has proven to be disadvantageous, as it requires a separate flowable component that must be pressed into the pressure relief valve orifice in a separate assembly step during the assembly of the pressure relief valve in order to support the helical spring, wherein the closing force generated in the helical spring and acting on the valve element or valve seat is limited, i.e., must be able to adjust the opening pressure of the pressure relief valve very precisely.

[0007] In contrast, the solution according to the invention differs from previously known solutions in that the pressure relief valve is arranged in a pressure relief valve orifice configured to pass through a through-hole in the pump body, wherein the pressure relief valve orifice extends from the damping region to the stepped chamber and is closed on the side pointing towards the damping region by a ball or a plug pressed into the pressure relief valve orifice, and the pressure relief valve orifice is implemented as a stepped orifice, comprising a first section with a larger diameter pointing towards the damping region and a second section with a smaller diameter pointing towards the stepped chamber, including an annular step formed between the first and second sections, on which a helical spring is supported.

[0008] The pressure relief valve of the pump according to the invention can be assembled in a simple and effective manner from the side of the pump housing facing the damping chamber, preferably first assembled with a helical spring such that the helical spring rests against the annular step. After the pressure relief valve is assembled in the pressure relief valve orifice, the pressure relief valve orifice can be easily closed by pressing in a ball or plug on the side facing the damping region.

[0009] In one extended configuration, the outlet valve is arranged in an outlet valve port on the pump housing, where the outlet valve port intersects with, in particular, the pressure relief valve port at a right angle. This eliminates the need for a separate high-pressure sealing component and integrates the pressure relief valve into the high-pressure area in a space-saving manner.

[0010] The outlet valve features a space-saving design with a movable valve element and a sealing seat portion upstream of the valve element. This sealing seat portion is fixed to the pump via a sealing seat portion-fixed section, and a sealing seat that interacts with the valve element is formed on this portion. A mating plate, fixed to the pump, is located downstream of the valve element and is also fixed to the pump via a mating plate-fixed section, restricting the downstream movement of the valve element. A pressure-limiting valve orifice intersects with the outlet valve orifice between the sealing seat portion-fixed section and the mating plate-fixed section. The pressure-limiting valve orifice then intersects with the space where components belonging to the outlet valve are assembled, giving this space a dual purpose.

[0011] Furthermore, an outlet pipe chamber can be formed between the pump housing and the outlet pipe. On one hand, the outlet pipe chamber can be constituted by or include the portion of the internal space of the pipe that points towards the pump housing. The outlet pipe chamber may also additionally include a recess in the pump body covered by the outlet pipe, and in particular, it can be formed by these two subspaces. Alternatively, the outlet pipe chamber can be formed by a recess in the pump body covered by the outlet pipe.

[0012] The outlet can be configured as an outlet pipe fixed to the pump housing, forming an outlet pipe chamber between the pump housing and the outlet pipe. An outlet valve is fixed in an outlet valve port in the pump housing, extending from the outlet pipe chamber. A pressure-limiting valve port is connected to the outlet pipe chamber via a high-pressure connection port located in the high-pressure area, extending from the outlet pipe chamber. In this configuration, the flexibility of the pressure-limiting valve port arrangement within the pump body is improved compared to the previously described solution.

[0013] If the outlet valve port and the high-pressure connection port are parallel to each other and arranged, for example, perpendicular to the longitudinal direction, they can be easily manufactured, for example, using the same tools or together.

[0014] If the outlet valve port and the high-pressure connection port are opposite each other at an angle other than 0° and are arranged, for example, perpendicular to the longitudinal direction respectively, the structural space available for the inner contour in the pump body can be optimized or the pump body can be potentially further reduced.

[0015] It can always be configured such that the imaginary (extended if necessary) central axis of the outlet valve orifice intersects the imaginary (extended if necessary) central axis of the pump piston, i.e., the longitudinal axis. Then, fuel can flow from the delivery chamber through the outlet valve without further deflection and with particularly low friction in this respect.

[0016] On the other hand, it is also advantageous, for the purpose of optimizing the use of the structural space available in the pump body, that the imaginary (extended if necessary) central axis of the outlet valve orifice does not intersect with the imaginary (extended if necessary) central axis of the pump piston, i.e., the longitudinal axis.

[0017] In the first additional subject matter currently claimed, a high-pressure fuel pump for a fuel system of an internal combustion engine is provided, comprising an inlet for supplying fuel, an outlet for discharging compressed fuel, a pump housing, a delivery chamber disposed within the pump housing, a pump piston movable in the pump housing in a longitudinal direction and defining the delivery chamber, an inlet valve disposed between the inlet and the delivery chamber and opening toward the delivery chamber, an outlet valve disposed between the delivery chamber and the outlet and opening away from the delivery chamber, a high-pressure region extending fluidly between the outlet valve and the outlet, and a low-pressure region extending fluidly between the inlet and the inlet valve. A pressure-limiting valve fluidly connects a high-pressure region and a low-pressure region and opens toward the low-pressure region, allowing fuel to flow from the high-pressure region to the low-pressure region when the pressure difference between the fuel in the high-pressure region and the fuel in the low-pressure region exceeds the opening pressure. The pump piston is constructed as a stepped piston, comprising a first section with a larger diameter pointing toward the delivery chamber and a second section with a smaller diameter pointing away from the delivery chamber. A high-pressure seal is disposed between the first section and the pump housing, allowing the pump piston to move within the high-pressure seal, which separates the delivery chamber from the low-pressure region. A pressure seal is arranged between the second section and a seal carrier fixed to the pump housing. This low-pressure seal separates the low-pressure region from the space outside the high-pressure fuel pump. A stepped chamber of the low-pressure region is located between the seal carrier and the pump housing. A pressure relief valve fluidly connects the high-pressure region and the stepped chamber of the low-pressure region and opens toward the stepped chamber, allowing fuel to flow from the high-pressure region into the stepped chamber when the pressure difference between the fuel in the high-pressure region and the fuel in the low-pressure region exceeds the opening pressure. An outlet valve is arranged in the outlet valve port of the pump housing and has a movable valve element, with [further details about the valve element]. The pump has a sealing seat portion that is fixed to the pump via a sealing seat portion-fixed section. A sealing seat that interacts with the valve element is formed on the sealing seat portion. The sealing seat portion also has a mating plate fixed to the pump and located downstream of the valve element. The mating plate is fixed to the pump via a mating plate-fixed section and restricts the downstream movement of the valve element. A pressure relief valve is arranged in a pressure relief valve orifice in the pump housing. The pressure relief valve orifice extends longitudinally and leads from the stepped chamber to the outlet valve orifice, specifically between the sealing seat portion-fixed section and the mating plate-fixed section.

[0018] Compared to the prior art cited at the beginning, and especially through the arrangement where the pressure relief valve orifice between the sealing seat section-fixed section and the mating plate-fixed section leads to the outlet valve orifice, there are the following advantages: the pressure relief valve can be integrated into the high-pressure area without additional high-pressure sealing parts and in a space-saving manner. The space where the components belonging to the outlet valve are assembled is also the orifice area of ​​the pressure relief valve orifice, thus serving a dual purpose.

[0019] It is advantageous to extend the first additional subject, i.e., preferably by means of... Figure 6 Neutralization / or in reference Figure 6 The features disclosed in the description.

[0020] In a second, additional subject matter currently claimed, a high-pressure fuel pump for a fuel system of an internal combustion engine is provided, comprising an inlet for supplying fuel, an outlet for discharging compressed fuel, a pump housing, a delivery chamber disposed within the pump housing, a pump piston movable longitudinally within the pump housing and defining the delivery chamber, an inlet valve disposed between the inlet and the delivery chamber and opening toward the delivery chamber, an outlet valve disposed between the delivery chamber and the outlet and opening away from the delivery chamber, a high-pressure region fluidly extending between the outlet valve and the outlet, a low-pressure region fluidly extending between the inlet and the inlet valve, and a pressure-limiting valve fluidly connecting the high-pressure region and the low-pressure region and opening toward the low-pressure region such that fuel flows from the high-pressure region to the low-pressure region when the pressure difference between the fuel in the high-pressure region and the fuel in the low-pressure region exceeds the opening pressure. The pump piston is configured as a stepped piston, comprising a first section pointing toward the delivery chamber and having a larger diameter and a second section having a smaller diameter and pointing away from the delivery chamber. A high-pressure seal is disposed between the first section and the pump housing. The piston is movable within the high-pressure seal, which separates the delivery chamber from the low-pressure region. A low-pressure seal is arranged between a second section and a seal carrier fixed to the pump housing, separating the low-pressure region from the space outside the high-pressure fuel pump. A stepped chamber of the low-pressure region is located between the seal carrier and the pump housing. A pressure relief valve fluidly connects the stepped chambers of the high-pressure and low-pressure regions and opens toward the stepped chamber, allowing fuel to flow from the high-pressure region into the stepped chamber when the pressure difference between the fuel in the high-pressure and low-pressure regions exceeds the opening pressure. The pressure relief valve is arranged in a pressure relief valve orifice in the pump housing, extending longitudinally and extending from the stepped chamber to a high-pressure connection orifice in the pump housing. This high-pressure connection orifice is arranged in the high-pressure region and oriented at an angle other than 0° relative to the outlet valve orifice. The outlet is specifically constructed as an outlet pipe fixed to the pump housing, forming an outlet pipe chamber, particularly between the pump housing and the outlet pipe, and both the outlet valve orifice and the high-pressure connection orifice originate from the outlet pipe chamber.

[0021] Compared to the prior art cited at the beginning, and especially by arranging the high-pressure connection hole relative to the outlet valve hole at an angle other than 0°, it is possible to optimize the use of the structural space available for the inner contour in the pump body or potentially further reduce the size of the pump body.

[0022] It is advantageous to further extend this to a second additional feature, namely, preferably by means of the feature that both the outlet valve port and the high-pressure connection port originate from the outlet pipe chamber. The ports can then be manufactured in a simple manner, for example, using the same tools.

[0023] Furthermore, a second additional subject matter can be advantageously extended by means of the features disclosed in FIG7 and / or in the description with reference to FIG7.

[0024] Within the scope of this invention, a hole (especially an outlet valve hole, a pressure relief valve hole, a low-pressure connection hole, a high-pressure connection hole, etc.) is particularly understood as the inner contour of a pump housing or pump body. This inner contour can be introduced into the pump housing or pump body from the outside by a rotating twist drill. Therefore, the hole is particularly axisymmetric, with its axis of symmetry corresponding to the axis of rotation of the twist drill. This axis of symmetry indicates the direction of the hole orientation. In the present case, the hole can essentially be a through hole through the pump housing or pump body or a blind hole terminating at the bottom of a hole arranged in the pump housing or pump body. Within the scope of this invention, the outlet of the hole is the side of the hole first formed by cutting when the drill bit penetrates into the pump housing or pump body. For a blind hole, this side is always the side opposite to the bottom of the hole. Therefore, if the hole meets or exits from another inner contour of the pump housing or pump body there, the opening of the hole is the side of the hole opposite to the outlet. The holes of the present invention, in particular, have no side recesses when viewed from their outlets.

[0025] Within the scope of this invention, for a through hole, the hole wall is the inner contour represented by the through hole; for a blind hole, the hole wall is a portion of the inner contour represented by the through hole, rather than the bottom of the hole.

[0026] Within the scope of this invention, the high-pressure area is understood as the entire space connected to the outlet, especially in the absence of an additional valve, such that a uniform pressure is present in the high-pressure area, for example, 500 bar when the pump is running.

[0027] Within the scope of this invention, the low-pressure region is understood to be the entire space connected to the inlet, especially in the absence of an additional valve, such that a uniform pressure is present in the low-pressure region, for example, 5 bar when the pump is running and when the low-pressure pump is connected to the inlet.

[0028] In particular, the inner contour through which the fuel flows in the high-pressure fuel pump is ultimately composed of a low-pressure region, a delivery chamber, and a high-pressure region. These regions are separated from each other by inlet valves, outlet valves, and pressure relief valves.

[0029] The fuel can be, for example, gasoline.

[0030] Within the scope of this invention, an angle different from 0° can be a significantly different angle, i.e., at least 2° or at least 5°. This angle can be, for example, between 2° and 90°. Attached Figure Description

[0031] Embodiments of the present invention will now be described with reference to the accompanying drawings. The drawings show: Figure 1 A simplified schematic diagram of a fuel system used in an internal combustion engine.

[0032] Figure 2 The first embodiment of the present invention.

[0033] Figure 3 Exemplary details of the pressure relief valve that may be used in the embodiments.

[0034] Figure 4: The second embodiment of the present invention.

[0035] Figure 5: The third embodiment of the present invention.

[0036] Figure 6 The fourth embodiment of the present invention.

[0037] Figure 7: The fifth embodiment of the present invention. Detailed Implementation

[0038] Figure 1 A simplified schematic diagram is shown of a fuel system 1 for an internal combustion engine (not shown further). When the fuel system 1 is running, fuel is supplied from the fuel tank 2 via a suction line 4, a pre-delivery pump 6, and a low-pressure line 8 via an inlet pipe 20 to a high-pressure fuel pump 10, implemented as a piston pump. An inlet valve 14 is fluidly disposed downstream of the inlet pipe 20. A low-pressure region 28 of the high-pressure fuel pump 10 is fluidly located between the inlet pipe 20 and the inlet valve 14. A delivery chamber 16 of the high-pressure fuel pump 10 is located downstream of the inlet valve 14. Pressure pulsations in the low-pressure region 28 can be attenuated by means of a pressure damping device. The inlet valve 14 can be forcibly opened by an operating device configured here as an electromagnetic actuator 30. The operating device and thus the inlet valve 14 can be controlled by a control unit 32.

[0039] The pump piston 18 of the high-pressure fuel pump 10 can move up and down along a longitudinal axis extending in the longitudinal direction LA by means of a driver 36, currently implemented as a cam. Figure 1 As shown by double arrows 40, the pump piston 18 is axially symmetrical with respect to the longitudinal axis. An outlet valve 37 is fluidly arranged between the delivery chamber 16 of the high-pressure fuel pump 10 and the outlet connector 35, opening towards the outlet connector 35 and the high-pressure reservoir 45 (“rail”) located further downstream. Therefore, the high-pressure region 29 of the high-pressure fuel pump 10 extends fluidly between the outlet valve 37 and the outlet connector 35.

[0040] High-pressure zone 29 and low-pressure zone 28 are directly interconnected by a pressure-limiting valve 22, which opens when the pressure exceeds the limit pressure in high-pressure zone 29 of fuel high-pressure pump 10, or in high-pressure reservoir 45 connected to that high-pressure zone. The pressure-limiting valve 22 is constructed as a spring-loaded check valve and can open toward low-pressure zone 28 of fuel high-pressure pump 10. In this way, the pressure that can be generated in high-pressure reservoir 45 by fuel high-pressure pump 10 is limited.

[0041] Figure 2 A high-pressure fuel pump 10, which is a first embodiment of the present invention, is shown in cross-section.

[0042] The high-pressure fuel pump 10 has an inlet 11 configured as an inlet pipe 20. In the absence of an intermediate connecting valve, the inlet 11 communicates with the entire low-pressure region 28 of the high-pressure fuel pump 10.

[0043] The high-pressure fuel pump 10 has an outlet 34 configured as an outlet pipe 35. In the absence of an intermediate connecting valve, the outlet 34 communicates with the entire high-pressure zone 29 of the high-pressure fuel pump 10.

[0044] The outlet pipe 35 and the inlet pipe 20 are fixed to the pump housing 12, in which a delivery chamber 16 is also arranged, which is limited by a pump piston 18 that can move along the longitudinal direction LA.

[0045] The low-pressure region 28 includes a damping chamber 28a, which is connected to the inlet 11 via a fluid connection invisible in its cross-section and is formed between the pump body 12a and the pump cover 12b of the pump housing 12. A diaphragm damper 55 is arranged in the damping chamber 28a, which may have a configuration of a flat and compressible box formed by two metal diaphragms.

[0046] The invisible fluid connection between inlet 11 and damping chamber 28a may, for example, include a filter orifice with a filter element that protects fuel flowing through the filter orifice from solid particles larger than the minimum size.

[0047] The sealing carrier 60 is fastened to Figure 2 A stepped chamber 28d is formed on the lower section of the pump body 12a and between the pump body 12a and the sealing carrier 60. The stepped chamber 28d communicates with the damping chamber 28a via a through hole that is not visible in the cross-section of the pump body 12a and is therefore part of the low-pressure region 28.

[0048] The delivery chamber 16 is limited to the low-pressure area 28 by the inlet valve 14, which opens toward the delivery chamber 16 when a corresponding pressure difference exists.

[0049] To control the delivery rate of the high-pressure fuel pump 10, the inlet valve 14 can be forcibly opened by a push rod 31 driven by the actuator 30. For this purpose, the actuator 30 has an actuator housing 30a fixed to the pump housing 12, in which an electromagnetic coil 30b is arranged, which can be energized via an externally accessible electrical connector 30c of the high-pressure fuel pump 10.

[0050] The inlet valve region 28c of the low-pressure region 28 is geometrically formed in the pump housing between the inlet valve 14 and the actuator 30. This inlet valve region communicates with the damping region 28a via an aperture 28f visible in this cross-section.

[0051] The delivery chamber 16 is confined toward the high-pressure area 29 by an outlet valve 37, which opens away from the delivery chamber 16 when a corresponding pressure differential exists. In this example, the outlet valve is arranged in an outlet valve port 37a of the pump housing 12 or pump body 12a. The outlet valve has a movable valve element 37.1 that interacts with a sealing seat 37.4, which forms a sealing seat portion 37.2 arranged upstream of the valve element 37.1 in a manner fixed to the pump. The downstream mobility of the valve element 37.1 is restricted by a mating plate 37.5 arranged in a manner fixed to the pump. The outlet valve port 37a originates from an outlet pipe chamber 35a located between the outlet pipe 35 and the pump housing 12 or pump body 12a.

[0052] The pump piston 18 is constructed as a stepped piston. The stepped piston has a first section 18.1 with a larger diameter pointing towards the delivery chamber 16 and a second section 18.2 with a smaller diameter pointing away from the delivery chamber (relative to the diameter of the first section 18.1). A space is formed between the first and second sections 18.1 and 18.2. Figure 2 The circular staircase 18.3 points vertically downwards.

[0053] A high-pressure seal 80 is disposed between the first section 18.1 and the pump housing 12, within which the pump piston 18 is movable. The high-pressure seal 80 sealably separates the delivery chamber 16 from the low-pressure region 28.

[0054] The high-pressure seal 80 can be, for example, a separate sealing ring, made of metal or plastic, as described in more detail in the applicant's WO 19 015 862 A1. Alternatively, the high-pressure seal 80 can also be a narrow gap extending over a certain length between the pump piston 18 and the sleeve or between the pump piston 18 and the pump housing 12, as described in more detail in the applicant's WO 06 069 819 A1.

[0055] A low-pressure seal 78 is disposed between the second section 18.2 and the aforementioned seal carrier 60, which separates the stepped chamber 28d of the low-pressure region 28 from the space 100 located outside the high-pressure fuel pump 10. The pump piston 18 is movable within the low-pressure seal 78.

[0056] The pump piston 18 is propelled along the spring plate 19.1 fixed to the pump piston 18 and the pump spring 19.2 clamped between the spring plate 19.1 and the sealing carrier 60. Figure 2 The longitudinal direction LA is pre-tightened downwards.

[0057] The fuel high-pressure pump 10 according to the invention has a pressure relief valve 22 that fluidly connects the high-pressure region 29 to the low-pressure region 28 and opens toward the low-pressure region 28, such that when the pressure difference between the fuel in the high-pressure region 29 and the fuel in the low-pressure region 28 exceeds the opening pressure, fuel flows out from the high-pressure region 29 into the low-pressure region 28.

[0058] Pressure relief valve Figure 3 The pressure relief valve is shown in detail and by way of example. The pressure relief valve has a valve seat body 38 pressed into the pressure relief valve orifice 22a or the housing of the pressure relief valve 22, on which a conical valve seat 42 is formed. The pressure relief valve 22 also has a valve element 44 having a spherical shape and sealingly abutting against the valve seat 42. The valve element 44 is pressed toward the closing direction by a retaining element 46, and the retaining element 46 is pressed toward the closing direction by a helical spring 52. The helical spring 52 is supported on the housing of the pressure relief valve 22 or directly on the pump housing 12. Here, the helical spring 52 abuts against the radially outer region 464 of the retaining element 46. The radially inner region 465 of the retaining element 46 is received by the helical spring 52. The opening pressure of the pressure relief valve 22 and thus simultaneously limit the maximum pressure difference that the fuel high-pressure pump 10 can generate between its inlet 11 and its outlet 34 are defined by the stiffness of the helical spring 52 and its effective area on the pressure relief valve.

[0059] The arrangement of the pressure relief valve 22 in the fuel high-pressure pump 10 according to the invention will now be discussed further by way of example.

[0060] Here, within the scope of the invention, a pressure relief valve 22 is configured to fluidly connect the high-pressure region 29 and the stepped chamber 28d of the low-pressure region 28 and open toward the stepped chamber 28d, such that when the pressure difference between the fuel in the high-pressure region 29 and the fuel in the low-pressure region 28 exceeds the opening pressure, fuel flows from the high-pressure region 29 into the stepped chamber 28d. The pressure relief valve 22 is arranged in a pressure relief valve orifice 22a configured to pass through a through-hole in the pump body 12b, wherein the pressure relief valve orifice 22a extends from the damping region 28a to the stepped chamber 28d and points toward the damping region 28a. One side is sealed by a ball 56 or a plug 57 pressed into the pressure relief valve orifice 22a. The pressure relief valve orifice 22a is implemented as a stepped orifice, which includes a first section 22.1 with a larger diameter facing the damping region 28a and a second section 22.3 with a smaller diameter facing the stepped chamber 28d, and an annular step 22.2 formed between the first section 22.1 and the second section 22.3. The helical spring 52 of the pressure relief valve 22 mentioned above is supported on the annular step 22.2 of the pressure relief valve orifice 22a.

[0061] According to the first embodiment of the present invention ( Figure 2 and Figure 3 Furthermore, the outlet valve port 37a and the pressure relief valve port 22a are arranged to intersect, particularly at right angles. Here, in this example, the intersection occurs within the high-pressure region 29.

[0062] More precisely, according to the first embodiment of the invention, the intersection is performed in such a manner that the sealing seat portion 37.2 is fixed to the pump by means of the sealing seat portion-fixed section 37.3, and the mating plate 37.5 is fixed to the pump by means of the mating plate-fixed section 37.6, and the pressure relief valve orifice 22a intersects with the outlet valve orifice 37a between the sealing seat portion-fixed section 37.3 and the mating plate-fixed section 37.6.

[0063] In this example, the imaginary central axis of the outlet valve orifice 37a is set to intersect with the imaginary central axis of the pump piston 18, and therefore, with the longitudinal axis of the gasoline high-pressure pump.

[0064] The second embodiment of the invention is shown in FIG4, partially in cross-sectional view in sub-view a) and in sub-view b) as a view of the pump body 12a shown in a semi-transparent manner. The second embodiment differs from the first embodiment in that the outlet valve port 37a and the pressure relief valve port 22a intersect. Instead, in the second embodiment, the pressure relief valve port 22a is connected to the outlet pipe chamber 35a via a high-pressure connection port 29a located in the high-pressure region 29 and extending from the outlet pipe chamber 35a.

[0065] Here, the outlet valve port 37a and the high-pressure connection port 29a are arranged relative to each other at an angle other than 0°, especially at least 20°, and are respectively perpendicular to the longitudinal direction LA.

[0066] The imaginary central axis of the outlet valve orifice 37a intersects in particular with the imaginary central axis of the pump piston 18.

[0067] The third embodiment of the present invention is shown in FIG. 5 in a partial cross-sectional view in sub-view a) and in sub-view b) as a view of the pump body 12a shown in a semi-transparent manner. The third embodiment differs from the second embodiment in that the outlet valve port 37a and the high-pressure connection port 29a are arranged parallel to each other.

[0068] In this example, the two holes 22a and 37a are arranged perpendicular to the longitudinal direction LA. The imaginary central axis of the outlet valve hole 37a does not intersect, or is not forced to intersect, the imaginary central axis of the pump piston 18.

[0069] The fourth embodiment of the present invention is in Figure 6The diagram is shown in cross-section. It relates to a high-pressure fuel pump 10 for a fuel system of an internal combustion engine, having an inlet 11 for supplying fuel, an outlet 34 for discharging compressed fuel, a pump housing 12, a delivery chamber 16 disposed within the pump housing, a pump piston 18 movable in the pump housing 12 along a longitudinal direction LA and defining the delivery chamber, an inlet valve 14 disposed between the inlet 11 and the delivery chamber 16 and opening toward the delivery chamber 16, an outlet valve 37 disposed between the delivery chamber 16 and the outlet 34 and opening away from the delivery chamber 16, a high-pressure region 29 extending fluidly between the outlet valve 20 and the outlet 34, a low-pressure region 28 extending fluidly between the inlet 11 and the inlet valve 14, and a pressure-limiting valve 22 that connects the high-pressure region 29 with... Low-pressure region 28 is fluidly connected and opens toward low-pressure region 28 such that when the pressure difference between the fuel in high-pressure region 29 and the fuel in low-pressure region 28 exceeds the opening pressure, fuel flows from high-pressure region 29 into low-pressure region 28. The pump piston 18 is constructed as a stepped piston, including a first section 18.1 with a larger diameter pointing toward delivery chamber 16 and a second section 18.2 with a smaller diameter pointing away from delivery chamber 16. A high-pressure seal 80 is disposed between the first section 18.1 and the pump housing 12. The pump piston 18 is movable within the high-pressure seal, which separates delivery chamber 16 from low-pressure region 28. A low-pressure seal 78 is disposed in the second section 18.2 and fixed to the pump housing 12. Between the sealing carriers 60 on the housing 12, the low-pressure seal separates the low-pressure region 28 from the space 100 outside the high-pressure fuel pump 10. The stepped chamber 28d of the low-pressure region 28 is located between the sealing carriers 60 and the pump housing 12. A pressure relief valve 22 fluidly connects the high-pressure region 29 to the stepped chamber 28d of the low-pressure region 28 and opens toward the stepped chamber 28d, such that when the pressure difference between the fuel in the high-pressure region 29 and the fuel in the low-pressure region 28 exceeds the opening pressure, fuel flows from the high-pressure region 29 into the stepped chamber 28d. An outlet valve 37 is arranged in the outlet valve port 37a of the pump housing 12 and has a movable valve element 37.1 and a sealing seat arranged upstream of the valve element 37.1. Section 37.2, the sealing seat portion is fixed to the pump by means of the sealing seat portion-fixed section 37.3 and a sealing seat 37.4 is formed on the sealing seat portion to cooperate with the valve element 37.1, and has a mating plate 37.5 fixed to the pump and arranged downstream of the valve element 37.1. The mating plate and the mating plate-fixed section 37.5 are fixed to the pump and restrict the movement of the valve element 37.1 in the downstream direction. The pressure relief valve 37 is arranged in the pressure relief valve hole 37 in the pump housing 12, which extends in the longitudinal direction LA and leads from the stepped chamber 28d to the outlet valve hole 22a, specifically between the sealing seat portion-fixed section 37.3 and the mating plate-fixed section 37.6.

[0070] The fifth embodiment of the invention is shown in FIG7, partially in cross-section in sub-view a) and in sub-view b) according to a view of the pump body 12a shown in semi-transparent form. It relates to a high-pressure fuel pump 10 for a fuel system of an internal combustion engine, having an inlet 11 for supplying fuel, an outlet 34 for discharging compressed fuel, a pump housing 12, a delivery chamber 16 disposed within the pump housing, a pump piston 18 movable in the pump housing 12 along the longitudinal direction LA and defining the delivery chamber, an inlet valve 14 disposed between the inlet 11 and the delivery chamber 16 and opening toward the delivery chamber 16, an outlet valve 37 disposed between the delivery chamber 16 and the outlet 34 and opening away from the delivery chamber 16, a high-pressure region 29 extending fluidly between the outlet valve 20 and the outlet 34, a low-pressure region 28 extending fluidly between the inlet 11 and the inlet valve 14, and a pressure relief valve 2. 2. The pressure relief valve fluidly connects the high-pressure region 29 and the low-pressure region 28 and opens toward the low-pressure region 28, such that when the pressure difference between the fuel in the high-pressure region 29 and the fuel in the low-pressure region 28 exceeds the opening pressure, fuel flows from the high-pressure region 29 into the low-pressure region 28. The pump piston 18 is constructed as a stepped piston, comprising a first section 18.1 pointing toward the delivery chamber 16 and having a larger diameter, and a second section 18.2 having a smaller diameter and pointing away from the delivery chamber 16. A high-pressure seal 80 is disposed between the first section 18.1 and the pump housing 12, and the pump piston 18 is movable within the high-pressure seal, which connects the delivery chamber 16 to the low-pressure region. Domain 28 is separated, wherein a low-pressure seal 78 is arranged between the second section 18.2 and a seal carrier 60 fixed to the pump housing 12, the low-pressure seal separating the low-pressure region 28 from the space 100 outside the fuel high-pressure pump 10, wherein a stepped chamber 28d of the low-pressure region 28 is located between the seal carrier 60 and the pump housing 12, wherein a pressure relief valve 22 fluidly connects the high-pressure region 19 and the stepped chamber 28d of the low-pressure region 28 and opens toward the stepped chamber 28d, such that when the pressure difference between the fuel in the high-pressure region 29 and the fuel in the low-pressure region 28 exceeds the opening pressure, fuel flows from the high-pressure region 29 into the stepped chamber 28d, wherein an outlet valve 37 is arranged on the pump housing. In the outlet valve port 37a of 12, a pressure relief valve 22 is arranged in the pressure relief valve port 22a in the pump housing 12. The pressure relief valve port extends in the longitudinal direction LA and leads from the stepped chamber 28d to the high pressure connection port 29a in the pump housing 12. The high pressure connection port is arranged in the high pressure region 29 and is oriented at an angle other than 0° relative to the outlet valve port 37a, for example, at an angle of 5° to 15°. The outlet 34 is specifically constructed as an outlet pipe 35 fixed to the pump housing 12. An outlet pipe chamber 35a is formed between the pump housing 12 and the outlet pipe 35. Both the outlet valve port 37a and the high pressure connection port 29a originate from the outlet pipe chamber 35a.

Claims

1. A high-pressure fuel pump (10) for a fuel system of an internal combustion engine, comprising: Inlet (11) for supplying fuel. The outlet (34) is used to output compressed fuel. Pump housing (12). Delivery chamber (16) arranged in the pump housing (12). A pump piston (18) is movable in the longitudinal direction (LA) within the pump housing (12), and the pump piston defines the delivery chamber (16). An inlet valve (14) is arranged between the inlet (11) and the conveying chamber (16), the inlet valve opening toward the conveying chamber (16). An outlet valve (37) is arranged between the conveying chamber (16) and the outlet (34), and the outlet valve opens away from the conveying chamber (16). High-pressure zone (29), the high-pressure zone fluid extends between the outlet valve (37) and the outlet (34), A low-pressure region (28) extends fluidly between the inlet (11) and the inlet valve (14), and A pressure relief valve (22) fluidly connects the high-pressure region (29) and the low-pressure region (28) and opens toward the low-pressure region (28) such that when the pressure difference between the fuel in the high-pressure region (29) and the fuel in the low-pressure region (28) exceeds the opening pressure, fuel flows from the high-pressure region (29) into the low-pressure region (28), wherein, The pump piston (18) is constructed as a stepped piston, having the following characteristics: The first section (18.1) pointing towards the conveying chamber (16) and having a larger diameter, and A second section (18.2) with a smaller diameter and pointing away from the delivery chamber (16), wherein a high-pressure seal (80) is arranged between the first section (18.1) and the pump housing (12), the pump piston (18) is movable within the high-pressure seal, and the high-pressure seal separates the delivery chamber (16) from the low-pressure area (28), wherein a... A low-pressure seal (78) separates the low-pressure region (28) from the space (100) outside the high-pressure fuel pump (10), wherein the stepped chamber (28d) of the low-pressure region (28) is located between the seal carrier (60) and the pump housing (12), wherein the pressure relief valve (22) fluidly connects the high-pressure region (29) to the stepped chamber (28d) of the low-pressure region and opens toward the stepped chamber (28d), such that when the high-pressure region (29)... When the pressure difference between the fuel in the high-pressure region (29) and the fuel in the low-pressure region (28) exceeds the opening pressure, the fuel flows out from the high-pressure region (29) into the stepped chamber (28d), wherein the pump housing (12) has a pump body (12a) and a pump cover (12b) connected to each other, wherein the pump body (12a) and the pump cover (12b) define a vibration damping region (28a) belonging to the low-pressure region (28), wherein at least one diaphragm damper (55) is arranged in the vibration damping region, wherein The pressure relief valve (22) is arranged in a pressure relief valve orifice (22a) configured to pass through a through hole in the pump body (12a), wherein the pressure relief valve orifice (22a) extends from the damping region (28a) to the stepped chamber (28d) and is closed on the side pointing towards the damping region (28a) by a ball (56) or a plug (57) pressed into the pressure relief valve orifice (22a), wherein the pressure relief valve orifice (22a) is implemented as a stepped orifice, having: The first section (22.1) has a larger diameter and points towards the damping region (28a). The second section (22.3), having a smaller diameter and pointing towards the stepped chamber (28d), and An annular step (22.2) is formed between the first section (22.1) and the second section (22.3), wherein the pressure relief valve (22) has a valve seat body (38) pressed into the pressure relief valve orifice (22a), and a conical valve seat (42) is formed on the valve seat body, wherein the pressure relief valve (22) has a valve element (44) that is sealed against the valve seat (42), wherein the valve element (44) is pressed toward the closing direction by a retaining element (46), wherein the retaining element (46) is pressed toward the closing direction by a helical spring (52), and wherein the helical spring (52) is supported on the annular step (22.2).

2. The high-pressure fuel pump (10) according to claim 1, wherein, The outlet valve (37) is arranged in the outlet valve hole (37a) of the pump housing (12), and wherein the outlet valve hole (37a) and the pressure relief valve hole (22a) intersect.

3. The high-pressure fuel pump (10) according to claim 2, wherein, The outlet valve (37) has a movable valve element (37.1) and a sealing seat portion (37.2) arranged upstream of the valve element (37.1), the sealing seat portion being fixed to the pump by means of a sealing seat portion-fixed section (37.3), and a sealing seat (37.4) forming on the sealing seat portion that interacts with the valve element (37.1), and has a mating plate (37.5) arranged downstream of the valve element (37.1) and fixed to the pump, the mating plate being fixed to the pump by means of a mating plate-fixed section (37.6) and restricting the downstream mobility of the valve element (37.1), and wherein a pressure relief valve orifice (22a) intersects the outlet valve orifice (37a) between the sealing seat portion-fixed section (37.3) and the mating plate-fixed section (37.6).

4. The high-pressure fuel pump (10) according to claim 1, wherein, The outlet (34) is constructed as an outlet pipe (35) fixed on the pump housing (12), and an outlet pipe chamber (35a) is formed between the pump housing (12) and the outlet pipe (35). The outlet valve (37) is fixed in the outlet valve hole (37a) of the pump housing (12), wherein the outlet valve hole (37a) extends from the outlet pipe chamber (35a). The pressure relief valve hole (22a) is connected to the outlet pipe chamber (35a) through a high-pressure connection hole (29a) located in the high-pressure area (29), wherein the high-pressure connection hole extends from the outlet pipe chamber (35a).

5. The high-pressure fuel pump (10) according to claim 4, wherein, The outlet valve port (37a) and the high-pressure connection port (29a) are arranged parallel to each other and perpendicular to the longitudinal direction (LA).

6. The high-pressure fuel pump (10) according to claim 4, wherein, The outlet valve port (37a) and the high-pressure connection port (29a) are arranged relative to each other at an angle other than 0° and are respectively perpendicular to the longitudinal direction (LA).

7. The high-pressure fuel pump (10) according to any one of claims 2 to 6, wherein, The imaginary central axis of the outlet valve orifice (37a) intersects with the imaginary central axis of the pump piston (18).

8. The high-pressure fuel pump (10) according to any one of claims 2 to 6, wherein, The imaginary central axis of the outlet valve orifice (37a) does not intersect with the imaginary central axis of the pump piston (18).

9. The high-pressure fuel pump (10) according to claim 1, wherein, The valve element has a spherical shape.

10. The high-pressure fuel pump (10) according to claim 2, wherein, The outlet valve orifice (37a) and the pressure limiting valve orifice (22a) intersect at right angles.

11. A high-pressure fuel pump (10) for a fuel system of an internal combustion engine, comprising: Inlet (11) for supplying fuel. The outlet (34) is used to output compressed fuel. Pump housing (12). Delivery chamber (16) arranged in the pump housing (12). A pump piston (18) is movable in the longitudinal direction (LA) within the pump housing (12), and the pump piston defines the delivery chamber (16). An inlet valve (14) is arranged between the inlet (11) and the conveying chamber (16), the inlet valve opening toward the conveying chamber (16). An outlet valve (37) is arranged between the conveying chamber (16) and the outlet (34), and the outlet valve opens away from the conveying chamber (16). High-pressure zone (29), the high-pressure zone fluid extends between the outlet valve (37) and the outlet (34), A low-pressure region (28) extends fluidly between the inlet (11) and the inlet valve (14), and A pressure relief valve (22) fluidly connects the high-pressure region (29) and the low-pressure region (28) and opens toward the low-pressure region (28) such that when the pressure difference between the fuel in the high-pressure region (29) and the fuel in the low-pressure region (28) exceeds the opening pressure, fuel flows from the high-pressure region (29) into the low-pressure region (28), wherein, The pump piston (18) is constructed as a stepped piston, having the following characteristics: The first section (18.1) pointing towards the conveying chamber (16) and having a larger diameter, and A second section (18.2) with a smaller diameter and pointing away from the delivery chamber (16), wherein a high-pressure seal (80) is arranged between the first section (18.1) and the pump housing (12), the pump piston (18) is movable within the high-pressure seal, and the high-pressure seal separates the delivery chamber (16) from the low-pressure region (28), wherein a low-pressure seal (78) is arranged between the second section (18.2) and a seal carrier (60) fixed to the pump housing (12), the low-pressure seal separating the low-pressure region (28) from the pump housing (16). 8) Separated from the space (100) outside the high-pressure fuel pump (10), wherein the stepped chamber (28d) of the low-pressure region (28) is located between the sealing carrier (60) and the pump housing (12), wherein the pressure relief valve (22) fluidly connects the high-pressure region (29) to the stepped chamber (28d) of the low-pressure region (28) and opens toward the stepped chamber (28d) such that fuel flows from the high-pressure region (29) when the pressure difference between the fuel in the high-pressure region (29) and the fuel in the low-pressure region (28) exceeds the opening pressure. The outlet valve (37) is disposed in the outlet valve port (37a) of the pump housing (12) and has a movable valve element (37.1), and has a sealing seat portion (37.2) disposed upstream of the valve element (37.1), the sealing seat portion being fixed to the pump by means of a sealing seat portion-fixed section (37.3), and a sealing seat (37.4) is formed on the sealing seat portion to cooperate with the valve element (37.1), and has a fixed section disposed downstream of the valve element (37.1). The pump has a mating plate (37.5) which is fixed to the pump by means of a mating plate-fixed section (37.6) and restricts the downstream mobility of the valve element (37.1). The pressure relief valve (22) is arranged in a pressure relief valve orifice (22a) in the pump housing (12), which extends along the longitudinal direction (LA) and leads from the stepped chamber (28d) to the outlet valve orifice (37a), specifically between the sealing seat portion-fixed section (37.3) and the mating plate-fixed section (37.6).

12. A high-pressure fuel pump (10) for a fuel system of an internal combustion engine, comprising: Inlet (11) for supplying fuel. The outlet (34) is used to output compressed fuel. Pump housing (12). Delivery chamber (16) arranged in the pump housing (12). A pump piston (18) is movable in the longitudinal direction (LA) within the pump housing (12), and the pump piston defines the delivery chamber (16). An inlet valve (14) is arranged between the inlet (11) and the conveying chamber (16), the inlet valve opening toward the conveying chamber (16). An outlet valve (37) is arranged between the conveying chamber (16) and the outlet (34), and the outlet valve opens away from the conveying chamber (16). High-pressure zone (29), the high-pressure zone fluid extends between the outlet valve (37) and the outlet (34), A low-pressure region (28) extends fluidly between the inlet (11) and the inlet valve (14), and A pressure relief valve (22) fluidly connects the high-pressure region (29) and the low-pressure region (28) and opens toward the low-pressure region (28) such that when the pressure difference between the fuel in the high-pressure region (29) and the fuel in the low-pressure region (28) exceeds the opening pressure, fuel flows from the high-pressure region (29) into the low-pressure region (28), wherein, The pump piston (18) is constructed as a stepped piston, having the following characteristics: The first section (18.1) pointing towards the conveying chamber (16) and having a larger diameter, and A second section (18.2) with a smaller diameter and pointing away from the delivery chamber (16), wherein a high-pressure seal (80) is arranged between the first section (18.1) and the pump housing (12), the pump piston (18) is movable in the high-pressure seal, and the high-pressure seal separates the delivery chamber (16) from the low-pressure region (28), wherein a low-pressure seal (78) is arranged between the second section (18.2) and a seal carrier (60) fixed to the pump housing (12), the low-pressure seal separating the low-pressure region (28) from the space (100) outside the fuel high-pressure pump (10), wherein the stepped chamber (28d) of the low-pressure region (28) is located between the seal carrier (60) and the pump housing (12), wherein the pressure relief valve (22) separates the high-pressure region (28) from the space (100) outside the fuel high-pressure pump (10), wherein the stepped chamber (28d) of the low-pressure region (28) is located between the seal carrier (60) and the pump housing (12), wherein the pressure relief valve (22) separates the high-pressure region (28) from the space (100) outside the pump housing (12). 9) Fluidly connected to and open toward the stepped chamber (28d) of the low-pressure region, such that when the pressure difference between the fuel in the high-pressure region (29) and the fuel in the low-pressure region (28) exceeds the opening pressure, fuel flows from the high-pressure region (29) into the stepped chamber (28d), wherein the outlet valve (37) is arranged in the outlet valve port (37a) of the pump housing (12), wherein the pressure limiting valve (22) is arranged in the pressure limiting valve port (22a) of the pump housing (12), the pressure limiting valve port extending along the longitudinal direction (LA) and extending from the stepped chamber (28d) to the high-pressure connection port (29a) of the pump housing (12), the high-pressure connection port being arranged in the high-pressure region (29) and oriented at an angle other than 0° relative to the outlet valve port (37a).

13. The high-pressure fuel pump (10) according to claim 12, wherein, The outlet (34) is constructed as an outlet pipe (35) fixed on the pump housing (12).

14. The high-pressure fuel pump (10) according to claim 13, wherein, An outlet pipe chamber (35a) is formed between the pump housing (12) and the outlet pipe (35).

15. The high-pressure fuel pump (10) according to claim 14, wherein, Both the outlet valve port (37a) and the high-pressure connection port (29a) originate from the outlet pipe chamber (35a).

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