EP4118316A1

EP4118316A1 - Component for an injection system, and injection system for mixture-compressing, applied-ignition internal combustion engines, and method for producing a component of this type

Info

Publication number: EP4118316A1
Application number: EP21701316.8A
Authority: EP
Inventors: Florian GRENZ; Frank Schneider; Goekhan Guengoer; Ralf Weber
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-03-12
Filing date: 2021-01-21
Publication date: 2023-01-18
Also published as: JP2023516816A; US20230099915A1; CN115280010A; WO2021180390A1; MX2022011271A; KR20220148280A; US11828255B2; DE102020203174A1

Abstract

A component (3; 3') for an injection system (1) for mixture-compressing, applied-ignition internal combustion engines, which component (3; 3') is used to meter in a highly pressurized fluid and is, in particular, a high pressure line (5) or a fluid distributor (2), comprising a main body (14; 13), on which at least one hydraulic connector (15 - 20) is provided, wherein: at least the main body (14; 13) is formed together with the connector (15 - 20) by single-stage or multiple-stage forging; an interior chamber (11) is formed in the main body (14; 13) by machining after the forging process; and wherein a connector duct (26 - 31), which intersects the interior chamber (11) in an intersection region (40 - 45), is formed in the connector (15 - 20) by machining after the forging process. It is proposed that the intersection region (40 - 45) is deburred by mechanical deburring. Furthermore, an injection system (1) and a method for producing a component (3; 3') of this type are specified.

Description

description

title

Components for an injection system and injection system for mixed-compression, externally ignited internal combustion engines as well as a method for manufacturing such a system

component

State of the art

The invention relates to a component, in particular a fuel line or a fuel distributor, for an injection system which is used for mixture-compressing, externally ignited internal combustion engines. In particular, the invention relates to the field of injection systems for motor vehicles in which fuel is injected directly into the combustion chambers of an internal combustion engine.

A method for producing a fuel distributor is known from DE 102016 115550 A1, in which a distributor pipe is produced from a forged blank. Austenitic steels with the material numbers 1.4301, 1.4306, 1.4307 and 1.4404 can be used here. It has been recognized here that forged blanks have inherent stresses from the forging process due to their production and that the corrosion resistance is reduced by the chromium carbides that are formed. In the known method, the chromium carbides produced by slow cooling are dissolved again by means of a controlled heat treatment between 850 ° C. and 1100 ° C. for more than 60 seconds. The mechanical properties and corrosion resistance are thereby improved. Since the heat treatment also improves the machining properties for drilling, milling and thread cutting, the heat treatment is preferably carried out on the unmachined forging blank.

Disclosure of the invention

The component according to the invention with the features of claim 1 and the injection system according to the invention with the features of claim 8 as well as the method according to the invention according to claim 9 have the advantage that an improved design and functionality are made possible. The measures listed in the subclaims allow advantageous developments of the component specified in claim 1, the injection system specified in claim 8 and the method specified in claim 9.

The injection system according to the invention is used for mixture-compressing, externally ignited internal combustion engines. The injection system according to the invention is used to inject gasoline and / or ethanol and / or comparable fuels and / or to inject a mixture with gasoline and / or ethanol and / or comparable fuels. A mixture can, for example, be a mixture with water. The component according to the invention is used for such injection systems.

At least the base body of the component is made from a material that is preferably a stainless steel, in particular an austenitic stainless steel. In particular, the material can be based on an austenitic stainless steel with the material number 1.4301 or 1.4307 or on a stainless steel comparable to this. A hydraulic connection provided on the base body can be designed as a high pressure inlet, high pressure outlet or other high pressure connection. The base body is then preferably formed as a forged blank together with the high pressure inlet and the at least one high pressure outlet and optionally one or more other high pressure connections during manufacture and further processed.

In a proposed embodiment of a fuel distributor, there are therefore significant differences from a soldering trail, in which a pipe for the soldering trail is machined and deburred before the add-on components are soldered on. The forged design enables a design for higher pressures in particular.

An essential difference to a high pressure rail for compression ignition internal combustion engines consists in the choice of material and the processing, in particular in the forging of a stainless steel. In contrast to electrochemical deburring (ECM deburring), there are significant differences. For ECM deburring, a separate system and a subsequent cleaning process are required, which account for a not inconsiderable part of the manufacturing costs. The proposed mechanical deburring, on the other hand, can easily follow a machining process and, in particular, can be carried out in the same machining center. This applies in particular to a retraction deburring proposed according to the advantageous development of claim 2, since one or more retraction deburrers are in can advantageously be integrated into the machining process. Thus, the production can be simplified and the unit cost can be reduced.

Another advantage of the proposed mechanical deburring compared to ECM deburring results in relation to a material condition. With ECM deburring, excess material or at least one burr at a bore intersection is electrochemically dissolved, with a material state that is practically free of compressive residual stresses. In contrast to this, in the case of a proposed embodiment, a material condition subject to compressive residual stress can be realized which has higher cyclical strengths, in particular under pulsating internal pressure loading. This results in particular in an advantageous further development according to claim 3. Thus, an additional process increasing strength, such as an autofrettage, can be avoided in an advantageous manner. Advantageous developments according to claim 4 and / or claim 5 are particularly advantageous here.

An advantageous geometric configuration is possible according to the advantageous development according to claim 6. In particular, advantageous deburring with a rotating deburring tool, in particular a retraction deburrer, is possible as a result.

An advantageous embodiment of the base body with the hydraulic connection or the hydraulic connections is possible according to claim 7. The mechanical deburring enables reliable process control. In the case of ECM deburring, for example, when an electrode is energized by a contact between the electrode and a burr to be removed, a short circuit could occur if the burr to be removed is too large, whereby the process would come to a standstill without material removal. This problem arises in particular with the proposed austenitic stainless steels, since these are comparatively difficult to machine.

Forging in particular can result in undesirable structural components such as delta ferrite and deformed martensite. The proposed mechanical deburring can also achieve reliable process control in this case. In the case of ECM deburring, on the other hand, uneven removal could result, since the dissolution behavior depends on the microstructure. The proposed mechanical deburring avoids such disadvantages even in the case of an advantageous embodiment according to claim 7. Corresponding advantages result from an advantageous development of the method according to claim 10 and / or claim 11.

Brief description of the drawings

Preferred exemplary embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawings, in which corresponding elements are provided with matching reference symbols. Show it:

1 shows an injection system for a mixture-compressing, externally ignited internal combustion engine with a component designed as a fuel distributor in a schematic sectional illustration according to an exemplary embodiment of the invention;

FIG. 2 shows the section of the component designated by II in FIG. 1 according to the exemplary embodiment in a detailed, schematic illustration; FIG.

3 shows the detail of the component, designated III in FIG. 1, corresponding to the exemplary embodiment in a detailed, schematic illustration in a section perpendicular to a longitudinal axis of the component and FIG

4 shows a schematic representation of a mechanical deburring of an intersection area to explain a possible embodiment of the invention.

Embodiments of the invention

1 shows an injection system 1 with a fuel distributor (fluid distributor) 2 in a schematic sectional illustration corresponding to an exemplary embodiment. In this exemplary embodiment, the fuel distributor 2 of the fuel injection system 1 is a component 3 designed according to the invention. Furthermore, a high-pressure pump 4 is provided. The high-pressure pump 4 is connected to the fuel distributor 2 via a fuel line 5 designed as a high-pressure line 5. At an inlet 6 of the high pressure pump 4, a fuel or a mixture with fuel is supplied as a fluid during operation. In this case, the high-pressure line 5 can also be designed as a component 3 'according to the invention in a corresponding manner. The fuel distributor 2 serves to store and distribute the fluid to injection valves 7 to 10 designed as fuel injection valves 7 to 10 and reduces pressure fluctuations and pulsations. The fuel distributor 2 can also serve to dampen pressure pulsations that can occur when the fuel injectors 7 to 10 are switched. During operation, high pressures p can occur in an interior space 11 of the component 3, at least at times. The high-pressure line 5 has hydraulic connections 12, 12 'designed as high-pressure inlet 12 and high-pressure outlet 12', which can optionally be interchanged, as well as a base body 13.

The fuel distributor 2 has a tubular base body 14 which is formed by forging in one or more stages. A hydraulic connection 15 designed as a high pressure inlet 15 and a plurality of hydraulic connections 16 to 19 designed as high pressure outlets 16 to 19 or cups 16 to 19 are provided on the tubular base body 14. Furthermore, a hydraulic connection 20 designed as a pressure sensor connection 20 is provided on the tubular base body 14. In this exemplary embodiment, the tubular base body 14, the high pressure inlet 15, the high pressure outlets 16 to 19 and the pressure sensor connection 20 are formed from a forged individual part 14 ′. The high pressure inlet 15, the high pressure outlets 16 to 19 and the pressure sensor connection 20 are thus forged onto the base body 14.

The fuel line 5 is connected at its high pressure inlet 12 to the high pressure pump 4 and at its high pressure outlet 12 ′ to the high pressure inlet 15 of the fuel distributor 2. The fuel injectors 7 to 10 are each connected to the high pressure outlets 16 to 19 of the fuel distributor 2. Furthermore, a pressure sensor 21 is provided which is connected to the pressure sensor connection 20. At one end 22, the tubular base body 14 is closed by a screw plug 23. In a modified embodiment, an axial high pressure inlet can be provided at one end 24 instead of the lateral and / or radial high pressure inlet 15.

After forging, the tubular base body 14 or the forged individual part 14 'is machined by at least one machining process. In this exemplary embodiment, a bore 25 is also formed in the tubular base body 14 after forging in order to form the interior space 11. During operation, the fluid supplied at the high pressure inlet 15 can be distributed to the fuel injection valves 7 to 10 connected to the high pressure outlets 16 to 19 via the interior 11. In addition, bores 26 to 31 are made in the forged individual part 14 'by machining. The holes 27 to 30 are used for the high pressure outlets 16 to 19. The hole 26 is used for the high pressure inlet 15. The hole 31 is used for the pressure sensor connection 20 get cut.

In addition, bores 32 to 37 can be provided at the high pressure inlet 15, the high pressure outlets 16 to 19 and the pressure sensor connection 20, which form connection spaces 32 to 37. In this exemplary embodiment, the bore 25 is oriented axially with respect to a longitudinal axis 38. The bores 26 to 37 are oriented radially or radially eccentrically with respect to the longitudinal axis 38. In the case of a radial or radial-eccentric orientation in relation to the longitudinal axis 38, when fastening in, for example, an engine compartment, an orientation of the bores 26, 31, 32, 37 of the connections 15, 20 or the bores 27 to 30, 33 to 36 can be preferred of the connections 16 to 19 above or below the longitudinal axis and / or from the longitudinal axis 38 pointing away from or pointing towards a motor.

Connection channels 26 to 31 that are intersected with the interior space 11 are formed by the bores 26 to 31. These connection channels 26 to 31 connect the bores 32 to 37 with the interior space 11. Here, the bores 26 to 31 are intersected with the bore 25 which forms the interior space 11. This results in intersection areas 40 to 45 on which burrs remain after the machining. The intersection areas 40 to 45 are deburred by mechanical deburring.

A possible configuration of the connections 15, 20 is described by way of example with reference to connection 15 with reference to FIG. 2. One possible configuration of the connections 16 to 19 is described by way of example with reference to the connection 16 with reference to FIG. 3. One possible configuration for mechanical deburring is described with reference to FIG. 4. This results in a possible configuration of a component 3 which is configured in accordance with an exemplary embodiment of the invention. In a corresponding manner, another component 3 'of the injection system 1 can also be implemented, for example the high-pressure line 5, with the connections 12, 12' being designed and mechanically deburred in a corresponding manner.

FIG. 2 shows the section of component 3, designated II in FIG. 1, corresponding to the exemplary embodiment in a detailed, schematic illustration. Between In this exemplary embodiment, a conical and / or step-shaped transition 46 is provided for bores 26, 32. In particular, the bores 26, 32 can be arranged coaxially in this case. Depending on the application, a suitable thread can also be implemented on the connection 15 in order to connect the high-pressure line 5, for example.

The deburring of the intersection region 40 can be carried out from the bore 32, as is also explained with reference to FIG. 4. As a result, a bevel 40 ′ can be formed on the intersection area 40.

3 shows the section of component 3 designated III in FIG. 1 according to the exemplary embodiment in a detailed, schematic representation in a section perpendicular to longitudinal axis 38 33 is arranged eccentrically to the bore 27. The bore 27 can be oriented radially to the longitudinal axis 38.

The bore 33 is then oriented radially eccentrically with respect to the longitudinal axis 38. The deburring of the intersection area 41 can take place from the bore 33, as is illustrated with reference to FIG. 4. As a result, a bevel 4 can be formed on the intersection area 41.

In this exemplary embodiment, the connection 15 can thus be designed in the form of a valve cup 15.

2 and 3 illustrate possibilities for realizing non-eccentric and eccentric connection geometries in which mechanical deburring can take place.

FIG. 4 shows a schematic illustration of mechanical deburring of an intersection region 40 by means of a return deburring tool 50 to explain a possible embodiment of the invention. The bores 25, 26 are intersected with one another in the intersection region 40. The return deburring tool 50 can be fed in via the bore 32 (FIG. 2) along an axis 51. The retraction deburring tool 50 has at least one cutting edge 52. During the feeding process, the cutting edge 52 is fully or partially folded into a jacket surface 53 of the return deburring tool 50. The cutting edge 52 can be folded out by means of a rotation 54 and / or by applying a cooling lubricant, which can be supplied via the return deburring tool 50. By withdrawing the retraction deburring tool 50 in a retraction direction 55, the rotation 54 results in a mechanical deburring of the intersection area 40 by means of the cutting edge 52. The rotation 54 and / or the supplied liquid cooling lubricant causes the cutting edge 52 to move against the intersection area 40 applied. The bevel 40 'can be formed in this case. The return deburring tool 50 can then be removed, the cutting edge 52 fully or partially folding back into the lateral surface 53.

Thus, a mechanical removal of a burr and a cutting edge removal in the intersection area 40 can be achieved. Depending on the configuration of the return deburring tool 50, the cutting edge 52 can also be held, for example, by a spring in order to facilitate the introduction and removal of the return deburring tool 50.

The timing of the machining for the design of the bores 25 to 37 can be implemented in a suitable manner. The mechanical deburring of the intersection areas 40 to 45 can be integrated into this processing or connected to it in a suitable manner.

In one possible implementation of the method, the bore 25 for the configuration of the interior 11 can first be drilled. The bores 32 to 37 for the connection geometries of the connections 15 to 20 can then be drilled and the bores 26 to 31 serving as connection channels 26 to 31 to the interior 11 can be drilled. The intersection areas 40 to 45 can then be mechanically deburred. Mechanical deburring can thus follow the machining process.

In one possible embodiment of the method, after drilling the bore 25 for the interior space 11, all connection geometries are machined, in particular all bores 32 to 37 are drilled, then all bores 26 to 31 serving as connection channels 26 to 31 or as connection bores 26 to 31 are drilled and finally all intersection areas 40 to 45 mechanically deburred.

A possible modification of this process is that a different sequence is implemented for drilling and deburring, which integrates the deburring into the machining process. If several intersection areas 40 to 45 are mechanically deburred, then a processing sequence can relate to one of the connections 15 to 20 in each case. This means, for example at the connection 15, that the bore 32 drilled, then drilled the bore 26 and then the mechanical deburring of the intersection area 40 takes place. These steps can be carried out one after the other for each of the connections 15 to 20 in a corresponding manner. This means that mechanical deburring does not necessarily take place after the machining process has been completed. In particular, mechanical deburring can thus also be integrated into the machining process. By means of suitable process parameters and the selection of a suitable cooling lubricant, it is also possible that an inner wall 60 extending from the bore 25 over the intersection area 40 and through the bore 26 is configured with a material condition subject to compressive residual stress. This inner wall 60 can also extend into the transition 46 (FIG. 2) or the hole bottom 47 (FIG. 3) and at least partially over the holes 32 to 37. The configuration of the inner wall 60 with the material condition subject to compressive residual stress results in an improved cyclic strength.

The invention is not restricted to the exemplary embodiments described.

Claims

Expectations

1. Component (3; 3 ') for an injection system (1) for mixture-compressing, externally ignited internal combustion engines, which is used to meter a fluid under high pressure, in particular high-pressure line (5) or fluid distributor (2), with a base body (14), on which at least one hydraulic connection (15-20) is provided, at least the base body (14) with the connection (15-20) being formed by a single or multi-stage forging, with the base body (14) being machined an interior space (11) is formed after forging and wherein a connection channel (26-31) intersected with the interior space (11) in an intersection region (40-45) is formed on the connection (15-20) by machining after forging is, characterized in that the intersection area (40-45) is deburred by mechanical deburring.

2. Component according to claim 1, characterized in that the intersection area (40-45) is deburred by mechanical retraction deburring.

3. Component according to claim 2, characterized in that a forged material of the base body (13) on an inner wall (60) of the base body (13), which is acted upon by the high pressure (p) of the fluid during operation, with a material condition subject to compressive residual stress is designed.

4. Component according to one of claims 1 to 3, characterized in that the inner wall (60) of the base body (13) configured with the material condition subject to compressive residual stresses delimits the interior space (11) and / or that the inner wall (60) configured with the material condition subject to compressive residual stresses ) of the base body (13) extends over the intersection area (40-45) and / or that the material state that is subject to compressive residual stress is formed Inner wall (60) of the base body (13) extends at least over the connection channel (26-31) of the hydraulic connection (15-20).

5. Component according to claim 4, characterized in that the hydraulic connection (15-20) has a connection space (32-37) which is connected to the interior space (11) via the connection channel (26-31), and that the The inner wall (60) configured with the material condition subject to compressive residual stress extends from the connection channel (26-31) at least partially over the connection space (32-37) of the connection (15-20).

6. Component according to one of claims 1 to 5, characterized in that the interior (11) of the base body (13) is formed by at least one bore (25) and / or that the connection channel (26 - 31) is formed by at least one bore ( 26 - 31) is formed.

7. Component according to one of claims 1 to 6, characterized in that the base body (13) and the at least one hydraulic connection (15-20) are formed from a forged individual part (14 ') and / or that the base body (13) is formed from a material that is based on an austenitic stainless steel, in particular an austenitic stainless steel with the material number 1.4301 or 1.4307 or on a stainless steel comparable to this.

8. Injection system (1) for mixture-compressing, externally ignited internal combustion engines, which is used to inject a fluid that is fuel, in particular gasoline and / or ethanol, and / or a mixture with fuel, with at least one component (3, 3 ') one of claims 1 to 7.

9. A method for producing a component (3; 3 ') for an injection system for a mixture-compressing, externally ignited internal combustion engine, which is used to meter a fluid under high pressure, the fuel, in particular gasoline and / or ethanol, and / or a mixture with fuel is used, in particular a method for producing a high-pressure line (5) or a fluid distributor (2), a base body (14; 13) and at least one hydraulic connection (15-20) provided on the base body (13) being or multi-stage forging can be formed, with a machining operation after forging on the base body (14; 13) Inner space (11) is formed and wherein a connection channel (26-31) which is blended with the inner space (11) in an intersection region (40-45) is formed on the connection (15-20) by machining after forging, characterized in that that the intersection area (40 - 45) is deburred by mechanical deburring.

10. The method according to claim 9, characterized in that a cutting edge (52) of a return deburring tool (50) serving for mechanical deburring is acted upon against the intersection area (40 - 45) for deburring by a liquid cooling lubricant supplied for cooling during mechanical deburring and / or that a cutting edge (52), used for mechanical deburring, of a return deburring tool (50) is acted upon for deburring by rotating the return deburring tool (50) against the intersection area (40-45).

11. The method according to claim 9 or 10, characterized in that a liquid cooling lubricant supplied for cooling during mechanical deburring is at least temporarily placed under such a high pressure that a forged material of the base body (13) on an inner wall (60) of the base body ( 13), which is acted upon by the high pressure of the fluid during operation, is designed with a material state subject to compressive residual stress.