WO2013182213A1

WO2013182213A1 - Fuel guiding component

Info

Publication number: WO2013182213A1
Application number: PCT/EP2012/002393
Authority: WO
Inventors: Andreas von der Osten-Sack; Ole Ohrt
Original assignee: Caterpillar Motoren Gmbh & Co. Kg
Priority date: 2012-06-05
Filing date: 2012-06-05
Publication date: 2013-12-12

Abstract

A fuel guiding component (200, 300, 400, 500, 600) for guiding pressurized fuel comprises a body (200, 300, 400, 500, 600) and a fuel passage (225) that is formed in the body (200, 300, 400, 500, 600) and comprises sections (240, 250) having different orientation, wherein a fuel stream passing during operational use of the fuel guiding component (200, 300, 400, 500, 600) through the fuel passage (225) may smoothly flow from one of the sections to another one of the sections. In some embodiments, sections may intersect at an angle larger than 90°, intersect within a pressure equalization chamber, or be partly curved.

Description

FUEL GUIDING COMPONENT

Technical Field

[01] The present disclosure generally refers to fuel systems and more

particularly to components of a fuel system for redirecting pressurized fuel.

Background

[02] The operation of internal combustion engines with alternative fuels may result in strong wear of those components of the fuel system that are in contact with the fuel. Specifically, fuel systems may be affected by the increased cavitation activity caused by an increased water content of alternative fuels.

[03] Additionally to the operation with alternative fuels, fuel systems may also be configured for interchanging operation with conventional fuels, including diesel fuels (DFO), light fuel oil (LFO), heavy fuel oil (HFO), or low and high sulphur fuels. Thus, generally, the fuel systems may become in contact with a large variety of types of fuels at various temperatures and pressures.

[04] Fuel systems may comprise high pressure fuel pumps using a plunger as disclosed, for example, in EP 2 339 166 Al . High pressure pumps may be used for marine engines, construction machine engines, or other large internal combustion engines.

[05] Fuel systems may further comprise various high pressure components such as a high pressure pump connector, short high pressure pipes, and long high pressure pipes. Finally, the fuel system may comprise an injection system.

[06] Alternative fuels include, for example, first generation biofuels (e.g. palm oil, canola oil, oils based on animal fat) and second generation biofuels (e.g. oils made of non food corps, i.e. waste biomass). Examples of second generation EP2012/002393

biofuel include "pyrolysis oils" obtained from the pyrolysis of, e.g., wood or agricultural wastes, such as the stalks of wheat or corn, grass, wood, wood shavings, grapes, and sugar cane. In particular, alternative fuels may have an increased water content of, for example, <26 % by volume as it may be the case for pyrolysis oils and ethanol based fuels as described in the European patent application EP 12 157 275.4 filed on 28 February 2012 by Caterpillar Motoren GmbH & Co. KG.

[07] The chemical composition and the physical properties of alternative fuels such as pyrolysis oils, ethanol based fuels, and of low-sulphur fuels can differ significantly from those of DFO, LFO, and HFO, in particular with respect to the high content of water and oxygen, the acidic pH-value in the range around, e.g., 2 to 3.5, and the rather low heating value. Moreover, alternative fuels and low- sulphur fuels can have poor or completely missing lubrication properties and usually comprise small size particles in the range of, e.g., 0.1-5μιη. Also the temperature of use is generally lower for alternative fuels and low-sulphur-fuels than for, e.g., HFO. For example, a temperature of use of 60°C is common for pyrolysis oils to provide a viscosity, which is suitable for fuels to be injected into a combustion chamber of an engine.

[08] Due to the chemical composition and the physical properties of alternative fuels, alternative fuels may have an increased cavitation and corrosion activity and increase the wear of the components of the fuel system.

[09] The present disclosure is directed, at least in part, to improving or

overcoming one or more aspects of prior systems.

Summary of the Disclosure

[10] According to a first aspect of the present disclosure, a fuel guiding

component for guiding pressurized fuel may comprise a body and a fuel passage that is formed in the body and comprises sections having different orientation. A fuel stream passing during operational use of the fuel guiding component through EP2012/002393

the fuel passage may smoothly flow from one of the sections to another one of the sections.

According to another aspect of the present disclosure, a fuel guiding component for guiding pressurized fuel may comprise a body, two openings formed in the body and having different orientation, and a fuel passage within the body and extending between the two openings. The fuel guiding component is configured such that a fuel stream generated during operational use of the fuel guiding component may smoothly flows from the first opening to the second opening through the fuel passage.

According to another aspect of the present disclosure, a fuel guiding component for guiding pressurized fuel may comprise a body with a fuel passage extending between two openings. The openings may open towards different directions and the fuel passage may be configured to connect the first opening and the second opening such that a fuel stream generated during operational use of the fuel guiding component my smoothly flow from the first opening to the second opening within the fuel passage.

In some embodiments of the fuel guiding component, the fuel passage may comprise a first linear section associated with a first one of the openings and a second linear section associated with a second one of the openings, wherein the first linear section and the second linear section may extend at an angle within the range from 30 ° to 60 ° with respect to each other such that a change in propagation direction of the fuel is within the range of 120 ° to 150 °.

In some embodiments of the fuel guiding component, the first linear section and the second linear section are associated with an inlet direction and an outlet direction, respectively, and the first linear section is angled with respect to the inlet direction within an angular range from 15° to 60 °and/or the second linear section is angled with respect to the outlet direction within an angular range from 15° to 60 °. At least one of the first linear section and the second 2 002393

linear section may be angled with respect to a face at which the respective opening is positioned.

In some embodiments of the fuel guiding component, at least one of the openings may be shaped in form of a cone and the cone is defined by a cone opening angle between a wall of the cone and an axis of the cone and the linear section extends at an angle with respect to the axis of the cone that is greater 5 °, for example, 10 ° and smaller than the cone opening angle.

In some embodiments of the fuel guiding component, the first linear section may extend linearly until it intersects with the second linear section. An intersection corner may be formed at the intersection having a corner angle larger than 90 °, for example, larger than 95 ° or 100 ° and, for example, the intersection corner is additionally rounded down.

In some embodiments of the fuel guiding component, the fuel passage may comprise a first channel section, a pressure equalization chamber, and a second channel section, wherein the first channel section and the second channel section fluidly connect the openings respectively with the pressure equalization chamber. For example, the first channel section may fluidly connect a first one of the openings to the pressure equalization chamber and the second channel section may fluidly connect a second one of the openings to the pressure equalization chamber.

In some embodiments of the fuel guiding component, a width of the pressure equalization chamber next to the opening into the first linear section may be wider than the width of the first linear section and/or a width of the pressure equalization chamber next to the opening into the second linear section may be wider than the width of the second linear section. For example, in some embodiments of the fuel guiding component, the pressure equalization chamber may extend in direction of the first linear section for at least 1.1 , for example, 1.2 times the extension of the second linear section in direction of the first linear section and/or the pressure equalization chamber may extend in direction of the 02393

-5- second linear section for at least 1.1 , for example, 1.2 times the extension of the first linear section in direction of the second linear section.

[19] In some embodiments of the fuel guiding component, the fuel passage may comprise a linear section and a bend channel section, wherein the bend channel section extends within a plane defined by the centers of the openings and a center axis of the linear section. The bending radius of the bend channel section may be in the range from 16 mm to 40 mm, for example, 22 mm.

[20] In some embodiments of the fuel guiding component, the body may

include at least one face in which one of the openings is formed and which is part-spherical. For example, a face surrounding at least one of the openings may be shaped half spherical.

[21] In some embodiments of the fuel guiding component, at least one of the openings may be at least part-conical. For example, at least one of the openings may be configured to open in a cone-shape.

[22] In some embodiments of the fuel guiding component, at least one of the openings may be configured to open into a cylindrical recess and the transition between the fuel passage and the cylindrical recess may be substantially conical.

[23] In some embodiments of the fuel guiding component, the openings may open towards different directions and the fuel passage may be configured to connect the openings such that a fuel stream generated during operational use of the fuel guiding component may reduce a fuel stream following closely around one or more sharp bends.

[24] In some embodiments, the fuel guiding component's body may be reshaped, configured as valve carrier, and/or configured as a high pressure pipe of a fuel pump.

[25] According to another aspect of the present disclosure, a fuel system for an internal combustion engine may comprise a fuel pump with a valve carrier, a short high pressure pipe and a long high pressure pipe; and an injection system, wherein at least one of the valve carrier, the short high pressure pipe, and the long 3

-6- high pressure pipe may be configured as a fuel guiding component as discussed above.

In some embodiments, the absence of steps within a fuel flow and/or of forced fuel flow around corners may reduced the cavitation activity during operation of the fuel system and in particular the respective component may, thereby, extend the component's and thus the fuel system's lifetime.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a side view of a schematically isolated fuel system for an internal combustion engine;

Fig. 2 is a top view of the schematically isolated fuel system of Fig. 1 ;

Fig. 3 is a side view with a partial cross-sectional side view of a plunger operated fuel pump;

Fig. 4 is a cut view of an exemplary embodiment of a redirecting element with non-orthogonal intersecting fuel channels;

Fig. 5 is a cut view of an exemplary embodiment of a redirecting element with a pressure equalization chamber;

Fig. 6 is a cut view of an exemplary embodiment of a short high pressure connector with a pressure equalization chamber;

Fig. 7 is a cut view of an exemplary embodiment of a valve carrier with a pressure equalization chamber; and

Fig. 8 is a cut view of an exemplary embodiment of a valve carrier with a continuously bend fuel channel section; and

Fig. 9 is a cut view of a prior art short high pressure connector. Detailed Description

The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described therein and illustrated in the drawings are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of patent protection. Rather, the scope of patent protection shall be defined by the appended claims.

The present disclosure is based on the realization that engines operated with fuels, which may have an increased cavitation activity, may be prone to a shortening of the lifetime of respective components of the fuel system due to increased surface wear and damaging. An increase in surface wear may be in particular the case for components when the fuel is pressurized and/or guided around corners. Initially the surface may be damaged on a micro-scale whereby the damages may then increase to fractions of the component. Once a surface is damaged, corrosive features of fuels may add to shortening the components lifetime.

The present disclosure is further based on the realization that cavitation may occur in fuel redirecting components. Specifically, when pressurized alternative fuel may be redirected by, for example, 90 °, it was realized that a corner formed by intersecting fuel channels may cause damaging cavitation downstream of the respective corner. This may be the case for the redirecting fuels components such as a valve carrier of the fuel pump and a short high pressure fuel connector. It was further realized that, in order to reduce the vulnerability to cavitation, one may adjust the component's geometry and, for example, remove any sharp corners or step-like geometries along the fuel path. In Fig. 1 and Fig. 2, a general fuel system 1 for an internal combustion engine is shown as a side view and as a top view, respectively. Fuel system 1 may comprise a high pressure fuel pump 10, a short high pressure pipe 12, a long high pressure pipe 14, and an injector system 16. In such a system, fuel may be pressurized in high pressure fuel pump 10 and provided to injector system 16. Specifically, high pressure fuel pump 10 may comprise a valve carrier 20 for connecting to high pressure pipes 12 and 14 and providing the pressurized fuel to an injection nozzle 22 of injection system 16.

High pressure fuel pump 10 may comprise a pump configuration as disclosed, for example, in (not-yet published) European patent application EP 11 176 050.0 filed on 29 July 2011 by Caterpillar Motoren GmbH & Co. KG.

In the following, an exemplary configuration and function of a high pressure fuel pump with a valve carrier is explained in connection with Fig. 3. In connection with Figs. 4 and 5, exemplary geometrical configurations of redirecting elements are generally described. Specifically, Fig. 4 shows an example of an angled channel configuration and Fig. 5 shows an example of a configuration of a fuel redirecting component having a pressure equalization chamber therein. Fig. 6 shows specifically an example of a high pressure fuel pipe with a pressure equalization chamber. For the embodiment of a valve carrier, Fig. 7 shows an exemplary configuration with a high pressure chamber and an additional chamfer face und Fig. 8 shows an exemplary configuration with a bend channel configuration. Fig. 9 shows a conventional short high pressure pipe interacting with a valve carrier.

Referring to Fig. 3, fuel pump 10 may comprise a pump housing 105, a pump barrel 110, a plunger 115, and a valve carrier 120. Pump housing 105 and pump barrel 110 may be substantially cylindrical, whereas plunger 115 may be pin-like. Valve carrier 120 may be cap-like.

At a pump head side 125 of fuel pump 10, pump housing 105 and pump barrel 1 10 may be closed with valve carrier 120. Valve carrier 120 may be connected to pump housing 105 by screws as schematically indicated in Fig. 2. Additional or alternative fasting elements may be used for connecting valve carrier 120 to pump housing 105.

At pump head side 125, fuel may be received, pressurized, and then provided as pressurized fuel via valve carrier 120 to injector system 16, for example, initially it may be provided to short high pressure pipe 12. The pressurization of the fuel may be performed by an oscillatory movement of plunger 115 within pump barrel 1 10 along an axial direction 128 of fuel pump 10. Axial direction 128 as indicated in Fig. 3 coincides with the plunger axis. To drive the oscillatory movement, plunger 115 may be connected, for example, with a camshaft of the internal combustion engine (not shown) at a pump body side 130 of fuel pump 10.

A pump chamber 135 may be provided at pump head side 125. Pump chamber 135 may be delimited by pump barrel 1 10 in a radial direction. Pump chamber 135 may further be delimited by plunger 115 at one axial side and valve carrier 120 at the opposing axial side. Within valve carrier 120, a spring forced high pressure valve - also referred to as flow limiter - (not shown) and a pressure relief valve (not shown) for constant pressure in the fuel line 14 may be arranged.

During the oscillatory movement of plunger 115, pump chamber 135 may continuously increase and decrease. During the increasing phase, fuel may enter pump chamber 135 while during the decreasing phase, the fuel may be

pressurized and then be released as pressurized fuel to injector system 16 via high pressure pipe connections 14 and 16.

Zero fuel grooves 137, a recessed surface section 139, and a circularly extending groove 140 may form a pressure release chamber 145 between pump barrel 1 10 and plunger 1 15. Pressure release chamber 145 may be in fluid connection with pump chamber 135 through zero fuel grooves 140 but may maintain its volume during the oscillatory movement of plunger 115. A control edge 170 (also referred to as helix) may define the transmission of sealing surface section 165 to recessed surface section 139. Control edge 170, thus, may define at which axial position the radial extension of plunger 115 may reduce from a maximal radius towards a reduced radius of the recessed surface section 139. Control edge 170 may extend, for example, in a helical manner around the axis of plunger 115. For example, control edge 170 may be shaped to continuously increase the length of the axial extension of sealing surface sections 165 and, thus, may enlarge the width recessed surface section 139 in azimuthal direction at a constant rate along axial direction 128. In general, the axial extension of sealing surface section 165 at an azimuthal angle may be set by selecting the path of control edge 170 along the plunger surface.

As further shown in Fig. 3, to provide fuel to pump chamber 135, a ring- shaped fuel gallery 175 may be formed between pump housing 105 and pump barrel 1 10. Fuel gallery 175 may surround pump barrel 110 at pump head side 125. Fuel gallery 175 may in principal be fluidly connected with the inside of pump barrel 110 via a pair of opposing fuel ports 180. Fuel gallery 175 may be connected to a large fuel reservoir (not shown).

During the oscillatory movement of plunger 115, fuel ports 180 may either open into pump chamber 135 (as shown in Fig. 3), be blocked by sealing surface sections 165, or open into pressure release chamber 145.

If plunger 110 is moving away from valve carrier 120, thus increasing pump chamber 135, sealing surface section 165 may not cover fuel port in particular around the turn around point and fuel may flow into pump chamber 135. When plunger 115 returns towards valve carrier 120, sealing surface may close fuel ports 180 and, during the plunger's further movement, the fuel in pump chamber 135 may be pressurized until control edge 170 of sealing surface sections 165 may reach fuel ports 180. Then, fuel ports 180 may fluidly connect fuel gallery 175 with pressure release chamber 145. 2 002393

During further movement of plunger 115 towards valve carrier 120, plunger 1 15 may push pressurized fuel out of pressure release chamber 145 into fuel gallery 175 along a passage delimited in radial direction by control edge 170 functioning as a side wall and in axial direction by the inner surface of pump barrel 110 and recessed surface section 139 of plunger 115.

As the axial position of control edge 170 may vary with the azimuthal angle of plunger 1 15, the axial position of plunger 115 for reopening fuel ports 180 and, thus, the time duration during which pressure is built up, may depend on the rotational position of plunger 115. Accordingly, the amount of fuel supplied by fuel pump 10 per pump cycle to injection system 16 may be controlled by rotating plunger 115. Specifically, depending on the angular position of plunger 115, pump chamber 135 may become fluidly connected to an outer fuel volume at an earlier or later time during the plunger oscillation.

To specifically control the amount of pumped fuel, fuel pump 10 may further be configured to allow rotating plunger 115 in response to a control signal requesting a specific amount of fuel being provided to the injector system.

At sharp corners along the fuel path within the valve carrier and/or the short and long high pressure pipes, cavitation may occur and affect, for example, the material and, thus, may limit the life time of the respective component and even may endanger neighboring and/or interacting components. For example, when fuel is redirected around a sharp corner, the flow may change from a rectified linear flow before the corner to a non-rectified (non-uniform) flow. After passing the corner, cavitation bubbles may be generated as the flow may break- off. The cavitation may become larger for an increased flow and pressure loss. The formation of the cavitation bubbles at the surface of the channel forming the fuel path may remove small amounts of material from the surface and, thus, may damage the same.

Fig. 4 shows schematically a fuel redirecting component 200 that allows redirecting pressurized fuel from an input direction 210 at an input side 215 to an 12 002393

-12- output direction 220 along a fuel passage 225. Input direction 210 and output direction 220 may be essentially orthogonal to each other.

At input side 215, a cone 230 may be provided with a cone opening angle a with respect to input direction 210. Cone opening angle a may be in the range from 15 ° to 30 °, for example, 22.5 °. Cone 230 may narrow down to an end diameter Dend.

A first linear section 240 of fuel passage 225 may extend at an angle β with respect to input direction 210 as indicated in Fig. 4 by a central axis 245 of first linear section 240. Angle β may be smaller than cone angle a such that, when, for example, drilling first linear section 240, a surface of cone 230 may not be damaged and, thus, may be maintained in its surface structure as it is prior the drilling. For example, the drill may not touch the wall of cone 230.

Fuel redirecting component 200 may further comprise a second linear section 250 extending along output direction 220. First linear section 240 may open into second linear section 250 under an intersection angle γ = 90 ° + β. Intersection angle γ may also correspond to the corner angle of a central corner 255. Further, an input corner 265 may have an input corner angle δ = 180 ° - (a + β)-

First linear section 240 and second linear section 250 may have diameter Din and diameter Dout, respectively. Diameters Din and Dout may be essentially identical, for example, in the range of 7 mm.

As an example, assuming cone angle a to be 22,5 °, angle β may be less than cone angle a but larger than a minimum angle such as 5 ° or 10 °. For example, angle β may be 10 °, 15 °, or 20 °. As an example, intersection angle γ (and correspondingly the angle of the central corner) may be 110 ° for an angle β of 20 °.

Further, assuming a counterpart is inserted into cone 230 and form a structural smooth transition from the counterpart to fuel redirecting component 200, the transition angle from the counterpart's inner channel to first linear section 240 may have an angle of input comer angle δ plus cone angle a and may be, for example, 160 ° for an angle β of 20 °.

In some embodiments, comer angle γ of a central comer 255 may further be increased (and, thus, the process of cavitation formation may further be reduced) by also tilting the direction of second linear section 250 with respect to output direction 220. Fig. 4 shows a tilted second linear section 250' with dashed lines.

In some embodiments, central comer 255 and/or input comer 265 may additionally be rounded as schematically indicated in Fig. 4 for central comer 255 and its opposing comer with dotted lines.

Although in Fig. 4, the input side is associated with cone 230, in some embodiments, the direction of flow along fuel passage 225 may be reversed. This may also apply for the following embodiments disclosed herein.

Referring to the embodiments of Fig. 4, as fuel passage 225 may not comprise sharp comers such as 90 ⁰ comers, the fuel may be redirected smoothly and cavitation may be reduced or avoided.

In Fig. 5 to 8, reference numerals as used in Fig. 4 are maintained for simplification of the drawings.

Fig. 5 shows schematically a fuel redirecting component 300 that may allow redirecting pressurized fuel from input direction 210 to output direction 220 being, for example, essentially orthogonal to input direction 210. An assumed intersection of a first linear section 240A and a second linear section 250A is indicated in Fig. 5 by dotted line extensions of those sections.

Instead of intersecting, linear section 240A and linear section 250A may each open into a pressure equalization chamber 310 (also referred to as a reservoir). Pressure equalization chamber 310 may have wall sizes that are at least 10 %, 20 %, 30 % larger than the diameters Din or Dout of the channels opening into the respective walls. 3

-14-

Accordingly, the walls may comprise wall sections 320 that may extend for at least, for example, 5 %, 10 %, or 15 % of the diameter of the respective channel section opening at each side of the channels. For illustration purposes, the extensions of wall sections 320 are shown enlarged in Fig. 5. In some manufacturing process even pressure equalization chambers of the size as indicated in Fig. 5 may be made and applied.

In some embodiments, corners 330 formed between the linear sections and walls sections 320 may additionally be rounded as schematically indicated in Fig. 5. Depending on the manufacturing process, curvature radii in the range of 0.2 mm to 1.3 mm may be applied.

As linear sections 240A and 250A may open into pressure equalization chamber 310, for example, centrally with respect to its walls, any flow of pressurized fuel from one linear section into the other may not need to tightly follow those corners but instead a flow through pressure equalization chamber 310 may form as indicated by an arrow 340. Thus, without the fuel passage needing to flow closely along 90 ° corners, cavitation formation may be reduced or even avoided.

As a specific example for the configuration of Fig. 5, Fig. 6 shows a short high pressure pipe 400 with a pressure equalization chamber 410 that may be rounded specifically at those ends and corners that may be reached with a machining tool inserted through cone 230 and a first linear section 240B. For short high pressure pipe 400, in- and outflow directions are reversed as described above for Fig. 5.

Specifically, short high pressure pipe 400 may comprise a valve carrier opening 410 open along output direction 220 at the end of a second linear section 250B. Second linear section 250B may be configured, for example, for interacting with cones 230 of the valve carriers shown in Figs. 7 and 8. may. As indicated in Fig. 6, valve carrier opening 410 may be arranged within a rounded 02393

-15- end piece that itself may be insertable into a cone of a downstream high pressure component.

A long high pressure pipe opening 420 of first linear section 240B may open along input direction 210 into cone 230 of short high pressure pipe 400.

As further shown in Fig. 6, pressure equalization chamber 410 may be wider in dimension and smoothly rounded at the side opposing long high pressure pipe opening 420 because form processing may be, for example, performed with tools inserted through long high pressure pipe opening 420. During operation of the fuel system, a fuel passage 455 may be provided through which the pressurized fuel may be smoothly redirected as schematically indicated by the spread of flow indicating arrows 440. For example, alternative fuel may be able to follow through short high pressure pipe 400 less influenced of any surface (including corner like features thereon) as the main stream may form at a distance from an outer surface 450 of pressure equalization chamber 410.

Pressure equalization chamber 410 may act as a (small) reservoir and may provide a buffer that may reduce the brake-off of the flow of fuel due to the lack of sharp corners and the remoteness of any corners from the main fuel path. In addition, the velocity may be equalized by the additional volume provided by pressure equalization chamber 410. Pressure equalization chamber 410 may function as a flow compensator and may reduce or even avoid cavitation at any corner-like structures.

As a specific example of a valve carrier in the configuration of Fig. 5, Fig. 7 shows a valve connector 500 with a pressure equalization chamber 510. For simplification, pressure equalization chamber 510 is illustrated similar to Fig. 5's pressure equalization chamber (reservoir) 310 although other shapes as, for example, indicated in Fig. 6 may be applied. The processing of pressure equalization chamber 510 may be performed as discussed above.

The embodiment of Fig. 7 shows as an additional valve carrier specific feature, a cone section 520 that smoothens the transition between a second linear section 250C and a cylinder-shaped recess 530. cCylinder-shaped recess 530 may be provided for accommodating, for example, a fuel limiter. The fuel limiter may function as an orifice (not shown). The fuel limiter may be configured as a spring forced fuel limiter interacting with a sealing surface 550. Cylinder-shaped recess 530 may allow inserting the fuel limiter. Cone section 520 may avoid having a 90 ° corner along fuel passage 540. Cone section 520 may have an opening angle (corresponding to twice the cone angle a indicated for cone 230 in Fig. 4) in the range of 10 ° to 25 °, for example, an opening angle of 20 °.

[73] In some embodiments of the valve carrier, the configuration of Fig. 4 may be combined with the additional feature of cone section 520 of Fig. 7.

[74] Fig. 8 illustrates a further exemplary configuration of a valve carrier 600 with a specific fuel passage implementation.

[75] Similar to Fig. 7, valve carrier 600 may comprise a cone section 520A providing a smooth transition from a second linear section 250D into a cylinder- shaped recess 53 OA.

[76] Instead of an pressure equalization chamber 510, valve carrier 600 may comprise a bend channel section 610 opening into cone 230. Bend channel section 610 may be processed (for example, eroded) to have a smooth curvature and forming a fuel passage that initially may extend lineary from second linear section 250D to cone 230 by continuously changing its direction. Bend channel section 610may avoid or even reduce cavitation formation. For example, the curvature of bend channel section 610may be in the range of 21 mm to 40 mm for a valve carrier and 16 mm to 31 mm for a short high pressure pipe.

[77] In Fig. 9, a conventional embodiment 900 of a short high pressure fuel pipe is illustrated that may connect a valve carrier 905 with a long high pressure pipe 910. Conventional embodiment 900 may comprise orthogonally extending channels - similar to the embodiment shown in Fig. 6 but does not have a pressure equalization chamber and, thus, subjects the fuel to a 90 ° corner 920. Industrial Applicability

[78] The features and embodiments of the structural configuration of the

components explained in connection with Figs. 4 and 8 may reduce or overcome alone or in combination disadvantageous affects caused by cavitation during operation of the fuel system.

[79] While some of the exemplary embodiments may be described specifically for a short high pressure pipe or a valve carrier, the same or a similar

configuration may be provided for other components of a high pressure fuel system as will be understood by the skilled person.

[80] The linear sections of the fuel passage described herein may be

configured as channels formed by drilling, turning, milling, grinding, and/or eroding. Additionally, a final polishing may be performed. In some embodiments, the inner surface of the fuel path within the components may be surface treated to further reduce cavitation.

[81] In some embodiments, the valve carrier and the high pressure pipes may be made of hardened steel.

[82] Although the preferred embodiments of this invention have been

described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.

Claims

1. A fuel guiding component (200, 300, 400, 500, 600) for guiding pressurized fuel, the component (200, 300, 400, 500, 600) comprising:

a body (200, 300, 400, 500, 600);

a fuel passage (225) formed in the body (200, 300, 400, 500, 600) and comprising sections (240, 250) having different orientation,

wherein a fuel stream passing during operational use of the fuel guiding component (200, 300, 400, 500, 600) through the fuel passage (225) smoothly flows from one of the sections to another one of the sections.

2. The fuel guiding component (200) of claim 1 , wherein the sections comprise a first linear section (240) associated with a first opening and a second linear section (250) associated with a second opening, wherein the first linear section (240) and the second linear section (250) extend at an angle within the range from 30 ° to 60 ° with respect to each other such that a change in propagation direction of the fuel is within the range of 120 ° to 150 °.

3. The fuel guiding component (200) of claim 2, wherein the first linear section (240) and the second linear section (250) are associated with an inlet direction (210) and an outlet direction (220), respectively, and the first linear section (240) is angled with respect to the inlet direction within an angular range from 15° to 60 °and/or the second linear section (250) is angled with respect to the outlet direction (220) within an angular range from 15° to 60 °.

4. The fuel guiding component (200) of claim 2 or claim 3, wherein an opening of at least one of the sections is substantially shaped in form of a cone (230) and the cone (230) is defined by a cone opening angle (d) between a wall of the cone (230) and an axis of the cone (230) and the linear section (240) extends at an angle (β) with respect to the axis of the cone (230) that is greater 5 °, for example, 10 ° and smaller than the cone opening angle (a).

5. The fuel guiding component (200) of any one of claim 2 to claim 4, wherein the first linear section (240) extends linearly until it intersects with the second linear section (250) and an intersection corner (255) is formed at the intersection having a corner angle (8) larger than 90 °, for example, larger than 95 ° or 100 ° and, for example, the intersection corner (255) is additionally rounded down.

6. The fuel guiding component (300, 400, 500) of claim 1, wherein the sections comprise a first channel section (240A, 240B, 240C), a pressure equalization chamber (310, 410, 510), and a second channel section (250A, 250B, 250C), wherein the first channel section (240A, 240B, 240C) fluidly connects a first opening to the pressure equalization chamber (310, 410, 510) and the second channel section (250A, 250B, 250C) fluidly connects a second opening to the pressure equalization chamber (310, 410, 510).

7. The fuel guiding component (300, 400, 500) of claim 6, wherein a width of the pressure equalization chamber (310, 410, 510) next to an opening into the first linear section (240A, 240B, 240C) is wider than the width (Din) of the first linear section (240) and/or a width of the pressure equalization chamber (310, 410, 510) next to an opening into the second linear section (250 A, 250B, 250C) is wider than the width (Dout) of the second linear section (250).

8. The fuel guiding component (600) of claim 1, wherein the sections comprises a linear section (250D) and a bend channel section (610), wherein the bend channel section (610) extends along a plane defined by the centers of openings, which are associated with the linear section (250D) and the bend channel section (610), and a center axis of the linear section (250D).

9. The fuel guiding component (600) of claim 8, wherein a bending radius of the bend channel section (610) is in the range of 16 mm to 40 mm, for example, 22 mm.

10. The fuel guiding component (200, 300, 400, 500, 600) of any one of the preceding claims, wherein the body includes at least one face in which one of the openings is formed and which is part-spherical.

11. The fuel guiding component (200, 300, 400, 500, 600) of any one of the preceding claims, wherein at least one of the openings is at least part-conical.

12. The fuel guiding component (200, 300, 400, 500, 600) of any one of the preceding claims, wherein the body is L-shaped, configured as valve carrier (120), and/or configured as a high pressure pipe (12, 14) of a fuel pump (1).

13. The fuel guiding component (200, 300, 400, 500, 600) of any one of the preceding claims, wherein an opening associated with one of the sections is configured to open into a cylindrical recess (53 OA) and the transition between the fuel passage and the cylindrical recess (530A) is substantially conical.

14. The fuel guiding component (200, 300, 400, 500, 600) of any one of the preceding claims, wherein openings associated with the sesctions open towards different directions and the fuel passage (225) is configured to connect the openings such that a fuel stream generated during operational use of the fuel guiding component (200, 300, 400, 500, 600) reduces a fuel stream following closely around one or more sharp bends.

15. A fuel system (1) for an internal combustion engine, the fuel system comprising:

a fuel pump (10) with a valve carrier (120),

a short high pressure pipe (12) and a long high pressure pipe (14); and

an injection system (16), wherein at least one of the valve carrier (120), the short high pressure pipe (12), and the long high pressure pipe (14) are configured as a fuel guiding component (200, 300, 400, 500, 600) as claimed in any one of the preceding claims.