EP3891378A1

EP3891378A1 - Component, in particular fuel line or fuel distributor, and fuel injection system

Info

Publication number: EP3891378A1
Application number: EP19783516.8A
Authority: EP
Inventors: Andreas Rehwald; Ralf Weber
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-12-07
Filing date: 2019-10-07
Publication date: 2021-10-13
Also published as: US20220003195A1; WO2020114650A1; US11408385B2; CN113167199A; DE102018221198A1

Abstract

A component (3) which can be designed as a fuel line (5) or fuel distributor (2) serves for a fuel injection system (1) which serves for injecting fuel or a mixture of fuel and water with a changeable portion of water. The component (3) has a main body (14; 60) on which a high-pressure input (15; 63) and at least one high-pressure output (16 - 19; 64) are provided, wherein the fuel or the mixture can be conducted from the high-pressure input (15; 63) through an interior (24; 65) of the main body (14; 60) to the at least one high-pressure output (16 - 19; 64), and wherein an insert (25) is arranged in the interior (24; 65). The insert (25) is at least partially formed from at least one material which has a bulk modulus (K) which is predefined so as to at least substantially correspond to or to be lower than a bulk modulus of the fuel or of the mixture and/or to be smaller than 30 GPa.

Description

Description title

Component, in particular fuel line or fuel distributor · and

Fuel injection system

State of the art

The invention relates to a component, in particular a fuel line or a fuel distributor, for a fuel injection system. Furthermore, the invention relates to a fuel injection system, which is preferably used as a fuel injection system for

mixture-compressing, spark-ignition internal combustion engines. In particular, the invention relates to the field of fuel injection systems for motor vehicles, in which fuel is directly injected into combustion chambers of an internal combustion engine. DE 10 2014 205 179 A1 is a fuel distributor rail for one

Internal combustion engine known. You can switch between two operating modes with and without water addition. The known fuel rail has an elongated housing with a cavity, a fuel inflow into the cavity and at least two fuel outlets from the cavity for one each

Fuel injector on. In this case, an insert body is arranged in the cavity, which has a groove which connects the two fuel outflows to one another and a groove which extends radially around the body in the region of the fuel inflow. The insert body with the two grooves serves as an insert, with which a direct inflow of fuel from a pump to the injectors is ensured. This results in a short delay before injection when switching between the operating modes with and without water admixture. The insert body can have an internal volume that serves for damping, but is not in the direct fuel flow.

The fuel rail known from DE 10 2014 205 179 A1 has the disadvantage that the insert reduces the volume that can be filled with fuel in the cavity of the housing, which reduces the achievable damping in relation to the required size. In addition, fuel with a not inconsiderable proportion of water can accumulate in the inner volume of the insert body during operation, which is difficult again can be reduced. When the engine is switched off, undesired segregation can then occur. There is also a risk of frost damage.

Disclosure of the invention

The component according to the invention with the features of claim 1 and the fuel injection system according to the invention with the features of claim 12 have the advantage that an improved design and functionality are possible. In particular, an improved injection with a short delay time and good damping behavior can be realized with a reliable mode of operation.

The measures listed in the subclaims are advantageous

Further developments of the component specified in claim 1 and the fuel injection system specified in claim 12 are possible.

The upper limit of 30 GPa corresponds, for example, to a plastic with a very high glass fiber content.

The proposed fuel injection system is used to inject a mixture, the mixture composition should be variable during operation. In particular, direct water injection can be implemented, in which water in an emulsion with at least one fuel, in particular gasoline, in combustion chambers

Internal combustion engine is injected. Here, the water can be in front of or in a

High pressure pump supplied to the fuel and together with this over the

Fuel distributors are promoted to high pressure injectors.

The composition of the mixture, in particular an emulsion of gasoline and water, can be varied as desired during operation. For example, the addition of water may only be necessary or desired in a certain map area. For example, water or a larger proportion of water at high speed and / or high load may be desired. If this map area is left, for example in the case of a fuel cut-off, it is advantageous if the injected water content can be reduced quickly and in particular quickly goes back to zero. This requires a short delay between the addition of the water before or in the high-pressure pump and its injection via the high-pressure injection valves. The volume of the component flowed through, in particular one

Fuel line or a fuel distributor, increases the delay time in principle. The arrangement of the insert body in the interior of the Base body enables a shortening of the delay time. By the

proposed insert body can be guaranteed sufficient compressibility despite the reduced hydraulic volume. Despite the reduced hydraulic volume, this results in further damping, in particular damping of pressure pulsations.

A reduction in the hydraulic volume in the interior of the base body of the component can advantageously be made possible by introducing the insert body, and at the same time sufficient compressibility can be ensured. At the same time, dead spaces can be avoided in which a mixture with a high water content could remain after operation has already started again with a low water content. Furthermore, the proposed insert body can also be used, for example, in a forged base body, as is advantageous in forged nails. Such a basic body can be closed with a sealing plug and does not have to go through a high-temperature process such as soldering or welding during manufacture. The sealing plug then enables a pressure and gas-tight seal of the interior.

Compression describes a compression of a body from all sides, which reduces the volume of the body or increases the density of the body. The

Compression module K can be defined as follows:

(1) K = -dp / (dV / V).

The compression module K is a measure of the infinitesimal pressure change dp that occurs with an infinitesimal volume change dV of a volume V. A reduction in volume is described here by a negative change in volume dV, which results in a positive change in pressure dp. The compression module K thus has a positive value and the unit Pascal. Depending on the pressure, the compression modulus K of water is, for example, in the range between 2 and 2.7 GPa. Depending on the temperature and pressure, a typical fuel can have a compression modulus of approximately 1 GPa, for example. Depending on the water content, a compression module of one results

Mixture of fuel and water, for example in the range from about 1 to about 2 GPa.

The material of the insert body is selected such that its compression modulus is at least essentially corresponding to or smaller than a compression modulus of the mixture. For example, an upper limit for the water content of the mixture be given. With regard to the maximum operating pressure, there is an upper limit for the fuel used for the area in which the compression module of the mixtures used in operation is located. It has been shown that the insert body can advantageously be designed in accordance with a further development according to claim 2 or 3. Here can

for example, a compression modulus K of about 1 GPa can be achieved. Depending on

Use can be achieved by an advantageous development according to claim 4, an increase in the compression module K. For example, one on

Polytetrafluoroethylene-based plastic can be filled with glass fibers. For example, the compression modulus K can be increased from approximately 1 GPa to approximately 2 GPa by a proportion of the glass fibers of 25%.

Depending on the design of the insert body, this can result in a temperature and / or pressure-dependent behavior. The compression modulus of an elastic, isotropic body is calculated accordingly from its modulus of elasticity E and the transverse contraction number v:

(2) K = E / (3-6v).

Since the modulus of elasticity E for thermoplastics drops for higher temperatures, while the number of transverse contractions v typically increases slightly, the compression modulus can decrease (ie the compressibility increases). If necessary, the

Compression module K can also be smaller than a compression module of a typical fuel. Depending on the design or the critical operating point, the hydraulic volume in the interior of the base body can then be reduced even further, with a reduction in the volume of the interior and thus smaller geometric dimensions of the base body being possible, which has an advantageous effect on the installation space required. A preferred one

Limitation of the compression module K is specified in claim 5. A bigger one

Compression modulus K can be achieved through the proportion and choice of additives. Preferably, however, the compression module K is not set much larger than that of water, as stated in claim 6. Thus, compared to a typical steel-based material from which a conventional insert body can be designed, the proposed insert body has a considerably lower compression modulus, since the compression modulus of steel is 160 GPa, for example. Depending on the composition, glass components can, for example, have a compression modulus from a range of 35 to 55 GPa. In addition to the elastic properties of the insert body, which can optionally be adapted by means of additives, in particular fillers, and the choice of the matrix material, plastics have the advantage that viscoelastic deformation can be achieved. The viscoelastic deformation not only results in elastic compressibility, but also a time-dependent deformation behavior.

This time-dependent deformation behavior can be used to achieve a suitable phase shift between the exciting load and the internal stress, which can make it possible to further improve the damping in relation to pressure pulsations that occur.

As a representative of thermoplastics, polytetrafluoroethylene (PTFE) is characterized by its high temperature and chemical resistance. It has been shown that polytetrafluoroethylene is particularly suitable for gasoline injection. It has also been shown that polytetrafluoroethylene shows a sufficiently low water absorption, which is in particular lower than that of polyamide. Furthermore, it has been shown that the mechanical stresses present in the system when there are local pressure differences can generally be tolerated without any problems, since they only minimally disrupt the hydrostatic stress state, and the function of the system is also not fundamentally endangered, even if it is locally too small plastic Deformation of the material is coming.

Other plastics that have similar properties to PTFE can also be used, for example perfluoroalkoxy polymers. Also suitable are, for example, fluoroethylene propylene, polyvenylidene fluoride, tetrafluoroethylene, hexafluoropropylene,

Vinyl idene fluoride and polychlorotrifluoroethylene. If this is appropriate, material combinations can also be used.

Another advantage of the thermoplastic is its low density. Although this is higher than that of the displaced liquid volume, it only leads to a slight relative increase in relation to the total mass of the fuel injection system, which is determined, for example, by steel components. As a result, there is no significant influence on vibration properties in the assembled state.

An advantageous embodiment of the insert body is possible according to claim 7. Starting from the basic shape of the insert body, adaptation to the geometry specified in the interior of the base body is possible, since the insert body can be designed to be deformable. A possible embodiment for positioning the insert body in the interior of the base body is specified in claim 8. In particular, two curved sections of the base body can be provided, between which the insert body is arranged. As a result, a reliable securing of the insert body in the interior is possible over the life of the fuel injection system, which can be used in particular with a component designed as a fuel line. Another possibility for fastening the insert body is possible according to claim 9.

In the case of solids, the compression module K plays a role when there is a hydrostatic stress state. This is particularly the case when the solid is pressurized on all sides. Such a loading condition is present when the insert body is arranged in the interior such that it is loaded on all sides with the prevailing pressure. In the case of solids, the hydrostatic stress state can be described by a stress tensor in which only the

Main diagonal is occupied with values of the same size, namely the negative applied pressure -p. According to the classic plasticity theory, such a state of tension never leads to permanent deformations and therefore cannot lead to failure, which has been experimentally confirmed, especially for metals. Using a finite element method or a finite element analysis, the effect on an insert body can be analyzed as part of a simulation. Such a simulation can aim to ensure that the mis-tension, i.e. according to the classic elasticity theory, the tension that is decisive for the plastic deformation of bodies and the associated damage, in particular with cyclical stress, at least essentially disappears.

It is therefore particularly important that the insert body is subjected to the high pressure as possible on all sides, so that a hydrostatic stress state is present. Since the insert body displaces or reduces a hydraulic volume, such a condition is approximately present apart from local pressure fluctuations due to the dynamics. In this way it can be achieved that the requirements for the strength of the material are considerably reduced and a suitable material class for the insert body can be selected in relation to the other relevant properties.

Thus, a further development according to claim 10 is particularly advantageous since one or more spacer elements can ensure that a hydrostatic one

Tension state is present. The development according to claim 1 1 has the advantage that the insert body can also be surrounded circumferentially by a spacer element can. The fuel flow can then be achieved via the through hole or the groove-shaped depression. The spacer elements can thus in particular also be designed in a ring shape. 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 corresponding reference symbols. Show it:

1 A shows a fuel injection system with a component designed as a fuel distributor in a schematic representation corresponding to a first

Embodiment of the invention;

1B shows a section through the component of FIG. 1A

Fuel injection system along the cutting line designated IB;

FIG. 2 shows a component designed as a fuel distributor for the fuel injection system shown in FIG. 1 in a schematic sectional illustration according to a second exemplary embodiment;

3A shows a component, designed as a fuel distributor, for the fuel injection system shown in FIG. 1 in a schematic sectional illustration in accordance with a third exemplary embodiment;

3B shows a section through the component of FIG. 3A shown in FIG

Fuel injection system along the cutting line designated IIIB; FIG. 4 shows a component designed as a fuel distributor for the component shown in FIG. 1

Fuel injection system in a schematic sectional view according to a fourth embodiment;

FIG. 5 shows a component designed as a fuel distributor for the fuel injection system shown in FIG. 1 in a schematic sectional illustration in accordance with a fifth exemplary embodiment; FIG. 6 shows a component designed as a fuel distributor for the fuel injection system shown in FIG. 1 in a schematic sectional illustration according to a sixth exemplary embodiment;

Fig. 7 shows a component designed as a fuel line in a schematic

Sectional representation correspond to a seventh embodiment;

Fig. 8 is a component designed as a fuel line in a schematic

Sectional representation correspond to an eighth embodiment;

9A shows a component designed as a fuel line in a schematic sectional illustration corresponding to a ninth exemplary embodiment and

FIG. 9B shows a section through the component shown in FIG. 9A along the section line designated IXB.

Embodiments of the invention

Fig. 1 shows a fuel injection system 1 with a fuel distributor 2 in a schematic representation according to a first embodiment. In this exemplary embodiment, the fuel distributor 2 is

Fuel injection system 1 around 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. A mixture of fuel and water is supplied to an inlet 6 of the high-pressure pump 4. The proportion of water can be changed and in particular can be reduced to zero.

The fuel distributor 2 is used to store and distribute fuel

Fuel injection valves 7 to 10 and thereby reduces the pressure fluctuations or pulsations. The fuel distributor 2 can also serve to dampen pressure pulsations that can occur when switching the fuel injection valves 7 to 10. The fuel distributor 2 is designed in such a way that when changing the water content there is a short delay in relation to the addition of the mixture at the inlet 6 of the high-pressure pump 4 to the injection of the mixture with the changed water content via the

Fuel injection valves 7 to 10 is reached.

The fuel distributor 2 has a tubular base body 14, which can be produced, for example, by forging. The tubular base body 14 has one High pressure inlet 15 and several high pressure outlets 16 to 19. Furthermore, a high-pressure connection 20 is provided on the tubular base body 14. The

Fuel line 5 is connected to the high pressure inlet 15. The

Fuel injectors 7 to 10 are connected to the high pressure outlets 16 to 19, respectively. Furthermore, a pressure sensor 21 is provided, which on the

High pressure connection 20 is mounted. At one end 22, the tubular base body 14 is closed by a closure 23 designed as a closure screw 23.

An interior space 24 is formed in the tubular base body 14. On the

Interior 24, the mixture 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. An insert body 25 is arranged in the interior 24, which reduces the hydraulic volume of the interior 24. This reduces a delay between the change in the water content of the mixture at the inlet 6 and the metering by the fuel injection valves 7 to 10.

The insert body 25 is formed from a material that has a compression module K that is at least substantially corresponding to or smaller than one

Compression modulus of the mixture passed through the interior space 24 is predetermined. The insert body 25 is preferably formed from a thermoplastic, in particular polytetrafluoroethylene. It is also possible for additives, in particular fillers such as glass fibers, to be provided in order to increase the compression modulus K of the insert body 25 if this makes sense in the respective application. For example, the compression modulus K of the material from which the insert body 25 is formed can be 2 GPa. The compression modulus K of the material is preferably not more than 3 GPa.

In this exemplary embodiment, the insert body 25 is based on a cylindrical basic shape 26. Here, on the cylindrical basic shape 26, there are several depressions 27,

28, 29 (Fig. 1 B), of which in Figs. 1A and 1 B exemplarily the

Wells 27 to 29 are shown. The recesses 27 to 29 are in this

Embodiment designed groove-shaped.

The insert body 25 is positioned in the interior 24 via spacer elements 30, 31. This ensures a distance 40 between an outer side 41 of the insert body 25 and an inner wall 42 of the tubular base body 14. This ensures that the insert body 25 is acted upon from all sides by the pressure p of the mixture which is passed through the interior 24. Pressure changes dp then lead to Volume changes dV of the volume V of the insert body 25, which are related to one another via the predetermined compression module K according to the formula (1). Since the compression module K is very small compared to steel, for example, the insert body 25 can make a significant contribution to damping. In particular, the material of the insert body 25 can be selected such that the compression module K is not greater than the compression module of the mixture passed through the interior 24. Then the insert body 25 only requires a reduction in the hydraulic volume, which shortens the delay time, but no reduction in the damping behavior with respect to the unfilled interior space 24, that is to say the entire volume of the interior space 24.

The spacer elements 30, 31 can in particular be designed as annular spacer elements 30, 31. The spacer elements 30, 31 prevent movement of the insert body 25 in the interior 24. In addition, these allow the

guaranteed distance 40 compensation for thermal

Expansion differences.

1B shows a section through the fuel distributor 2 of the fuel injection system 1 shown in FIG. 1A along the section line labeled IB. In the area of the spacer element 30, the groove-shaped depressions 27, 29 are formed on the cylindrical basic shape 26 of the insert body 25. This allows the mixture to flow along a longitudinal axis 43 (FIG. 1A) of the tubular base body 14.

FIG. 2 shows the fuel distributor 2 of the fuel injection system 1 shown in FIG. 1 in a schematic sectional illustration corresponding to a second one

Embodiment. In this exemplary embodiment, a recess 27 is formed on the cylindrical basic shape 26 of the insert body 25, which extends along the longitudinal axis 43 over the entire length of the cylindrical basic shape 26. The section shown with IB in FIG. 2 results in an unchanged representation corresponding to FIG. 1 B, even if the embodiment is modified. Another depression 29 is thus symmetrically opposite the depression 27 with respect to the longitudinal axis 43. This configuration is particularly suitable if a larger number of annular spacer elements 30 to 34 is provided, as is illustrated in FIG. 2. The spacer elements 30, 34 can then be configured in particular as O-rings.

The number of depressions 27 to 29 illustrated in FIGS. 1A, 1 B and 2 can vary with respect to the respective application. Reliable positioning of the insert body 25 in the interior 24 is thus ensured by the spacer elements 30 to 34. The distance 40 then enables a reliable one Flow of the remaining hydraulic volume in the interior 24 with the mixture. On the other hand, for example, temperature-related

Changes in length, which can be different for the insert body 25 and the tubular base body 14, ensure that a certain distance 40 is maintained and in particular that the contact body 25 lies flat against the inner wall 42 of the tubular base body 14.

If spacer elements 30 to 34 are provided, then these can be provided in a number and configuration as well as in an arrangement with corresponding spacings that high natural frequencies result.

FIG. 3A shows a fuel distributor 2 for the fuel injection system 1 shown in FIG. 1 in a schematic sectional illustration corresponding to a third

Embodiment. In this exemplary embodiment, the insert body 25 has a through bore 45 which in this exemplary embodiment extends axially through the cylindrical basic shape 26. Furthermore, the insert body 25 has at least one transverse bore 46. The transverse bore 46 connects the through bore 45 to the hydraulic volume of the inner space 24. This enables the hydrostatic pressure p to be present everywhere on the insert body 25 and the spacer elements 30, 31, which can be designed as O-rings 30, 31, not inadvertently Take on a sealing function that could have a negative impact on pressure fluctuations. In a modified embodiment, a plurality of through bores 45 can also be used

be provided. Another advantage of at least one through bore 45 and optionally at least one transverse bore 46 is that heat dissipation for cooling the material of the insert body 25 is made possible. As a result, the viscoelastic deformation caused by

Pressure fluctuations occurring during operation of the heating of the material of the insert body 25 are dissipated in an improved manner. In this case, in particular, the transverse bore 46 can be assigned to the high-pressure inlet 15 in order to increase the flow through the insert body 25.

FIG. 3B shows a section through the fuel distributor 2 shown in FIG. 3A along the section line labeled 3B. In contrast to that with reference to FIG. 1B

illustrated embodiment, no depressions 27 to 29 are required in the cylindrical basic shape 26 in this embodiment, so that these can be omitted.

FIG. 4 shows a fuel distributor 2 for the fuel injection system 1 shown in FIG. 1 in a schematic sectional illustration in accordance with a fourth exemplary embodiment. In this exemplary embodiment there are 25 at the axial ends of the insert body

Spacers 50, 51 are provided in order to position the insert body 25 in the interior 24 of the tubular base body 14. The spacer elements 50, 51 can be designed as elastically deformable spacer elements 50, 51. In this

The exemplary embodiments are the spacer elements 50, 51 as spring elements 50, 51

formed to compensate for differences in thermal expansion and relative movements between the insert body 25 and the tubular base body 14. Mechanical relative movements can also be compensated for here. FIG. 5 shows a fuel distributor 2 for the fuel injection system 1 shown in FIG. 1 in a schematic sectional illustration according to a fifth exemplary embodiment. In contrast to the exemplary embodiment described with reference to FIG. 4, the insert body 25 has an axial through bore 45. By a suitable one

Design of the spring elements 50, 51, for example in the form of spiral springs 50, 51, allows a flow through the through hole 45. A transverse bore 46 (FIG. 3A) can also be provided here.

FIG. 6 shows a fuel distributor 2 for the fuel injection system 1 shown in FIG. 1 in a schematic sectional illustration corresponding to a sixth

Embodiment. In this exemplary embodiment, spacer elements 52, 53, 54 are molded onto the cylindrical basic shape 26. The spacers 52 to 54 can

for example, be injection molded onto the cylindrical basic shape 26. The spacer elements 52 to 54 are designed in the manner of a sleeve in this exemplary embodiment. In a preferred embodiment of the insert body 25 made of a suitable plastic, the spacer elements 52 to 54 can optionally also be injection molded directly during the molding. Depending on the shape and flexibility, these molded-on spacer elements 52 to 54 allow temperature and relative movements to be compensated. A suitable number of such spacer elements 52 to 54 is provided in order to achieve the required or desired number of support points on the

To allow inner wall 42 of the tubular base body 14.

FIG. 7 shows a component 3 designed as a fuel line 5 for the fuel injection system 1 shown in FIG. 1 in accordance with a seventh exemplary embodiment. The fuel line 5 has a tubular base body 60. A high-pressure inlet 63 and a high-pressure outlet 64 are implemented in a suitable manner at the ends 61, 62 of the tubular base body 60. Depending on the configuration, it is also conceivable that the high pressure inlet 63 and the high pressure outlet 64 can be interchanged. The high-pressure inlet 63 is in the assembled state of the fuel injection system 1 however, on the high-pressure pump 4 and the high-pressure outlet 64 enables the connection to the fuel distributor 2, as is shown schematically in FIG. 1A.

The component 3 designed as a fuel line 5 is now designed in a corresponding manner. The insert body 25 is arranged in an interior 65. A distance 40 is ensured by spacer elements 30, 31 between the outside 41 of the cylindrical basic shape 26 of the insert body 25 and an inner wall 66 of the tubular base body 60. The flow of the mixture in a flow direction 67 through the interior 65 is ensured by depressions 27, 28. Here, in

corresponding further depressions may be provided.

When producing the fuel line 5, the insert body 25 can first be inserted into a central section 68 of the tubular base body 60. Then the tubular base body 60 can be suitably bent, in this

Embodiment two curved sections 69, 70 are provided, between which the insert body 25 is positioned. The insert body 25 can, for example, be inserted with a gauge into the central section 68 before the raw body 60 is bent, which remains straight after the bending.

Fig. 8 shows a fuel line 5 in a schematic sectional view

according to an eighth embodiment. In this exemplary embodiment, the insert body 25 has a through bore 45 configured as a cylindrical bore. This also results in a hydrostatic state. The dimensioning of the through bore 45, through which the mixture flows in the flow direction 67 during operation, can also achieve a throttling or orifice effect. Depending on the design of the spacer elements 52, 53, 54, 55, the space between the outer side 41 of the insert body 25 and the inner wall 42 of the tubular can also be

Base body 60 are flowed through by the mixture. For example, the spacer elements 52 to 55 can be like the one described with reference to FIG. 6

Embodiment to be designed arm-shaped. By specifying the distance 40 and / or the dimensioning of the through hole 45, a targeted throttling or orifice effect can thus be achieved.

9A shows a fuel line 5 in a schematic sectional illustration

according to a ninth embodiment. Furthermore, FIG. 9B shows a section through the fuel line 5 shown in FIG. 9A along the section line designated IXB. In this embodiment, the insert body 25 is formed from a material that is easy to form. In particular, a well formable plastic can be used as the material come. The insert body 25 is arranged in the curved section 69 of the tubular base body 60. In this case, the insert body 25 can be inserted into an initially straight tubular base body 60 during manufacture and then bent with the tubular base body 60. The bent section 69 then fixes the insert body 25. To between the outside 41 of the insert body 25 and the

To ensure a spacing 40 between the inner wall 42 of the tubular base body 60, spacing elements 52 to 55 designed as spacing ribs or longitudinal elevations are provided in this exemplary embodiment. The spacer elements 52 to 55 are preferably configured over the entire length of the insert body 25 on the outside 41 of the insert body 25. This ensures that the hydrostatic pressure p acts essentially on the entire outside 41 of the insert body 25.

As a result, a hydrostatic load condition can also be ensured in this exemplary embodiment. The spacer elements 52 to 55 prevent the insert body 25 from resting flat against the inner wall 42 of the tubular base body 60.

In addition to the exemplary embodiments described, other interior spaces of a fuel injection system 1 can also be correspondingly partially reduced in terms of their hydraulic volume. The reduced hydraulic volume combined with a high one

Compressibility and damping due to viscoelastic effects allow faster pressure build-up compared to conventional systems. Especially if the

Compression modulus K smaller and the internal damping of the insert body 25 is greater than that of the mixture, then a reduction in the installation space is also made possible. Furthermore, pressure pulsations and thus hydraulic excitations can be reduced, which results in shorter reaction times, especially in fuel injection systems 1

Allows water injection. Thus, an advantageous application in general in fuel injection systems 1 for injecting fuel is also conceivable, which relates in particular to applications for direct fuel injection.

The invention is not restricted to the exemplary embodiments described.

Claims

Expectations

1. component (3), in particular fuel line (5) or fuel distributor (2), for a fuel injection system (1), which is used to inject fuel or a mixture of fuel and water with a variable water content, with a base body (14; 60 ), at which a high pressure inlet (15; 63) and at least one

High pressure outlet (16-19; 64) are provided, the fuel or the mixture from the high pressure inlet (15; 63) through an interior (24; 65) of the base body (14; 60) to the at least one high pressure outlet (16-19; 64) can be guided and an insert body (25) is arranged in the interior (24; 65),

characterized,

that the insert body (25) is formed from at least one material, the one

Compression module (K), which is at least substantially predetermined or less than a compression module of the fuel or the mixture and / or less than 30 GPa.

2. Component according to claim 1,

characterized,

that the insert body (25) is at least partially formed from a plastic, in particular a thermoplastic.

3. Component according to claim 1 or 2,

characterized,

that the insert body (25) is at least partially formed from a plastic based on polytetrafluoroethylene, at least one perfluoroalkoxy polymer, fluoroethylene propylene, polyvinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride or polychlorotrifluoroethylene.

4. Component according to claim 2 or 3,

characterized,

that the plastic has additives.

5. Component according to one of claims 1 to 4,

characterized, that a proportion of the additives is specified so that a compression modulus (K) of the material is not greater than about 2 GPa.

6. Component according to one of claims 1 to 5,

characterized,

that the compression modulus (K) of the material is not greater than about 3 GPa.

7. Component according to one of claims 1 to 6,

characterized,

that the insert body (25) is based on an at least approximately cylindrical basic shape (26).

8. Component according to one of claims 1 to 7,

characterized,

that the base body (60) has at least one bent section (69, 70) and that a displacement of the insert body (25) in the interior (65) is limited by the bent section (69, 70).

9. Component according to one of claims 1 to 7,

characterized,

that the base body (60) has at least one bent section (69) and that the insert body (25) is at least partially arranged and bent in the bent section (69).

10. Component according to one of claims 1 to 9,

characterized,

that at least one spacer element (30 - 34; 50 - 55) is provided, by which a flat contact of the insert body (25) against an inner wall (42) of the base body (14; 60) is prevented.

1 1. Component according to one of claims 1 to 10,

characterized,

that the insert body (25) has at least one through hole (45) and / or that the insert body (25) has at least one groove-shaped recess (27 - 29) on its outside.

12. Fuel injection system (1), which serves to inject fuel or a mixture of fuel and water with a variable water content, with at least one component (3) according to one of claims 1 to 1 1.