WO2016091606A1 - Nozzle body and fluid injection valve - Google Patents

Abstract

A nozzle body (10) for a fluid injection valve (1) and a fluid injection valve (1) are specified. An inner surface (210) of a wall (20) of the nozzle body (10) defines a blind bore. At least one injection duct (40) penetrates the wall (20) from the inner surface (210) as far as an outer surface (220). A first section (410) of the injection duct (40) extends from an inlet opening (412) in the inner surface (210) to a transition region (415). A second section (420) extends from the transition region (415) as far as an outlet opening (422) in the outer surface (220). The equivalent diameter (D1) of the inlet opening is at least 1.5 times as large as the equivalent diameter (D2) of the second section (420) in the transition region (415), and the length (L1) of the first section (410) is between 5% and 15% of the length (L) of the injection duct (40).

Description

description

Nozzle Body and Fluid Injector Valve The present disclosure relates to a nozzle body for a fluid injector and a fluid injector.

Fluid injectors are used for the injection of

Fuel used in internal combustion engines. It can

Fuel from the nozzle body of the fluid injection valve are injected directly into a combustion chamber of the internal combustion engine.

For example, from DE 199 37 961 AI is known to design shape, size and contour of the exit region of a through hole in a valve seat deviating from the remaining region of the through hole to achieve a large variant frame with respect to the flow, spray angle and spray properties.

It is an object of the present disclosure to provide an improved nozzle body for a fluid injection valve, with which in particular a particularly low-emission combustion can be achieved.

This object is achieved by a nozzle body according to the independent claim. Advantageous embodiments and further developments of the nozzle body and of the fluid injection valve are specified in the dependent claims.

According to a first aspect, a nozzle body for a

Fluid injection valve disclosed. According to a second aspect, a fluid injection valve is disclosed with the nozzle body. The fluid injection valve is, in particular, a fuel injection valve, preferably a gasoline or diesel injection valve. The fluid injection valve is preferably designed for the injection of fuel directly into the combustion chamber of an internal combustion engine. The nozzle body is hollow. In other words, it has a wall whose inner surface defines a blind hole. In one embodiment, the fluid injector has a valve body that hydraulically connects a fluid inlet region of the injector to a fluid outlet region of the injector. The nozzle body is preferably arranged in the fluid outlet region. In particular, it is firmly connected to the valve body - for example, it is inserted into the valve body - or it is designed in one piece with the valve body. Preferably, it closes off the valve body on the outlet side.

The nozzle body has at least one injection channel penetrating the wall from the inner surface to an outer surface of the wall. The outer surface of the wall is in particular that surface of the wall which faces the combustion chamber during operation of the fluid injection valve and in particular is exposed at least in places in the combustion chamber.

In a preferred embodiment, the nozzle body has a plurality of injection channels, which are constructed in particular similar. For the sake of simplicity, the following description will be made only on the basis of an injection channel where appropriate, even if the nozzle body has several injection channels. However, in this case, the described features can be implemented on several or all of the injection channels.

The injection channel has a first portion and a second portion that follows the first portion downstream. The first section extends from an inlet opening of the injection channel, which is arranged in the inner surface of the wall, to a transition region. The transition region is arranged in particular within the wall, between the inner surface and the outer surface. The second portion extends from the transition region to an exit port of the injection port located in the outer surface.

Preferably, an interface between the first and second sections represents the transition region. The equivalent diameter of the entrance opening is at least 1.5 times the equivalent diameter of the second section in the transition area. In a further development, the equivalent diameter of the inlet opening is at most 2.5 times as large as the equivalent diameter of the second section in the transition region.

Under the equivalent diameter is meant in the present context, in the case of a circular opening or inlet of a circular cross-section of the second section in the transition region ^¬ over the respective diameter. If the inlet opening or the shape of the second section deviates from a circular shape in the transition area, the equivalent diameter is the diameter of the same area of the projecting area. In other words, it is the diameter of that circular area, which has the same area as the inlet opening or the

Cross sectional area of the second section in the transition area. In addition, the first section has a length that is between 5% and 15% of the length of the injection channel, with the limits included. In one development, the length of the first section has a value that is between 10% and 30% of the equivalent diameter of the second section in the transition area, including the boundaries. The length of the injection channel is in particular the sum of the lengths of the first section and the second section.

Advantageously, by means of the first portion of a particularly small in relation to its diameter length of the second

Section of the injection channel achievable. In this way, for example, a particularly small penetration depth of the fuel spray cone emitted from the injection channel into the

Combustion chamber of the internal combustion engine achievable. At the same time by means of the arrangement of the first section on the inner surface of the wall, the risk is particularly low that form deposits at the outlet opening of the injection channel, which lead to undesirable particle emission. This danger would be present the arrangement of the first section in the region of the outlet opening. In addition, due to the dimensions of the first section, the volume of the blind hole is relatively little increased, so that the emerging from the blind hole after the flow of the valve, undesirable fuel quantity ver ^¬ can be kept comparatively low.

In one embodiment, the first portion has a cylindrical shape. In this case, the transition region may be suitably formed by a bottom surface of the first portion in which a fluid inlet port of the second portion is arranged. The equivalent diameter of the second section in the transition region in this case is the equivalent diameter of the fluid inlet port of the second section. By means of the bottom surface, in particular a step is formed in the injection channel, at which the injection channel is discontinuously tapered.

In an alternative embodiment, the first section tapers from the inlet opening to the transition area. In particular, it tapers conically. For example, it has the shape of a truncated cone whose top surfaces are formed by the inlet opening of the injection channel and the fluid inlet opening of the second section. In this way, with a given volume of the first section, a particularly small length of the second section can be achieved.

In a further embodiment, the second section has a cylindrical shape or tapers in the direction of the outlet opening. In this way, the risk of undesirably large particle emission - caused, for example, by coking of the nozzle body at the outlet opening - particularly low. In one embodiment, the nozzle body has a longitudinal axis and has a plurality of injection channels distributed around the longitudinal axis in the wall. In particular, the injection channels are spaced from the longitudinal axis. You can be arranged at equal angular intervals from one another about the longitudinal axis and / or be arranged in the direction of the longitudinal axis at the same axial position. Depending on the desired shape of the discharged from the nozzle body

Fluid spray is also another, for example asym ^¬ metric arrangement of the injection channels conceivable. The injection channels have in a development a Längsmit ^¬ telachse, which is inclined by about 30 ° relative to the longitudinal axis. For example, the slope has a value between 20 ° and 40 °, with the limits included.

In one embodiment, the length of the injection channel has a value between 0.3 mm and 0.4 mm, z. B. of 0.36 mm. In a further embodiment, the length of the first section has a value between 0.025 mm and 0.04 mm, for example 0.027 mm or 0.035 mm. In a further embodiment, the equivalent diameter of the inlet opening between 0, 32 mm and 0, 5 mm, for example, it is 0, 4 mm or 0, 35 mm. In a further embodiment, the equivalent diameter of the second section in the transition region has a value between 0.1 mm and 0.28 mm, for example a value of 0.15 mm or 0.2 mm. For the value ranges, the limits are included. These lengths and diameters are - each in itself, but especially in combination with each other - in terms of achieving a comparatively low

Increasing the blind hole volume and a particularly small ratio of length to diameter of the second section particularly advantageous. In one embodiment, the fluid injection valve has a movable closure member that cooperates with a valve seat on the inner surface of the wall of the nozzle body, so that in a closed position, in which the closing element bears against the valve seat, fluid flow through the at least one injection channel is prevented and in others Positions of the closing element is released. The closing element is arranged in particular at the tip of a nozzle needle of the fluid injection valve. In one embodiment, the volume of the first portion or - in the case of a plurality of injection channels - the total volume of very first portions is at most as large and preferably at most half as large as a volume bounded by the inner surface downstream of the valve seat and the closure member. The volume bounded by the inner surface downstream of the valve seat and the closing element together with the volume of the first section or the total volume of the first sections is also referred to as "dead volume". It includes that amount of fuel, the raw ^¬ intends in the closed position can be released from the injection channel or the injection channels. In the fluid injection valve according to the present disclosure, the dead volume is advantageously comparatively small.

In one embodiment, the volume defined by the inner surface downstream of the valve seat and the closure member has a value of less than or equal to 0.05 mm ^ and / or greater than or equal to 0.03 mm ^. The volume of the first section or the total volume of all first sections, in one embodiment, has a value of 0.015 mm ^ and 0.028 mm ^, including the limits. In one embodiment, the volume defined by the inner surface downstream of the valve seat and the closure member has a value of 0.04 mm ^ and the total volume of the first portions has a value of 0.02 mm ^. Such volumes are particularly advantageous for the manufacturability of the nozzle body and its fluid discharge behavior.

Further advantages and advantageous embodiments and further developments of the nozzle body and of the fluid injection valve will become apparent from the following exemplary embodiments illustrated in conjunction with the figures.

Show it:

1 shows a schematic longitudinal section of a section of a nozzle body according to a first embodiment ^¬ example and 2 shows a schematic longitudinal section of a section of a fluid injection valve according to a second embodiment. In the exemplary embodiments and figures, similar, identical or identical components are provided with the same reference numerals. The figures and the proportions of the elements shown therein are not to be considered in scale. Rather, individual components may be exaggerated for better understanding or better representability.

1 shows a schematic sectional view of a section of a nozzle body 10 according to a first embodiment. More specifically, it is a longitudinal section along a longitudinal axis 12 of the nozzle body 10, wherein the part of the nozzle body 10, which lies in the sectional plane of Figure 1 to the left of the longitudinal axis 12 is omitted for simplicity of illustration.

The nozzle body 10 has a wall 20 which has a rotationally symmetrical with respect to the longitudinal axis 12 basic shape. By means of the wall 20, a blind hole 30 is formed. In other words, the nozzle body is hollow and has a cavity formed by the blind hole, in particular fuel leading.

The wall 20 has an inner surface 210 which defines the blind hole 30 of the nozzle body 10 and a surface facing away from the blind hole 30 outer surface 220. The nozzle body 10 is provided in particular for a fluid injection valve 1, which is adapted to fuel in a combustion chamber of an internal combustion engine, a ^¬ injecting. In this case, the outer surface 220, or at least a part thereof, in the operation of the fluid injection valve 1 is an interface between the fluid injection valve 1 and the combustion chamber.

The wall 20 is penetrated by at least one injection channel 40. In other words, the blind hole 30 is at one axial end of the nozzle body 10 through the wall 20 to the injection port 40 or the injection ports 40 completed.

In the present case, the nozzle body 10 has a plurality of injection channels 40, for example, it has six injection channels 40. The injection channels are spaced from the longitudinal axis 12 and penetrate the wall 20 from the inner surface 210 to the outer surface 220. Each injection channel 40 has a central axis 45, which is inclined relative to the longitudinal axis 12, for example by an angle between 20 ° and 40 °, wherein the limits are included ^¬ . In the present case, the angle of inclination of the central axes 45 to the longitudinal axis 12 is about 30 °.

The injection channels 40 are arranged, for example, at equal angular intervals around the longitudinal axis 12. Other

Arrangements, for example an asymmetrical distribution around the longitudinal axis 12 and / or other as well as different angles of inclination are also conceivable. The nozzle body 10 can also have an injection channel 40 which overlaps with the longitudinal axis 12.

In the present embodiment, each of the injection ports 40 is composed of a first portion 410 and a second portion 420. The first portion 410 extends from an entrance opening 412 located in the inner surface 210 of the wall 20 to a transition area 415, which is presently formed by a bottom surface of the first portion 410 and a fluid inlet opening of the second portion 420, the fluid inlet opening is arranged in the bottom surface of the first section. The inlet opening 412 delimits the injection channel 40 and the first section 410 toward the blind hole 30.

The second section extends from the fluid inlet opening in the transition region 415 to an outlet opening 422 which is arranged in the outer surface 220 of the wall 20. The off ^¬ outlet opening 422 limits the injection channel 40 and the second Section 420 on the outer surface 220, ie on the outside of the nozzle body 10th

The first portion 410 and the second portion 420 each have a cylindrical shape in the present embodiment. The diameter D1 of the first section 410 is twice as large as the diameter D2 of the second section. For example, the diameter D1 of the first section 410 is 0.4 mm and the diameter D2 of the second section 420 is 0.2 mm. The length LI of the first section 410 - this is the distance between the inlet opening 412 and the bottom surface in the transition region 415 - is 7.5% of the total length L of the injection channel 40. The total length L is the sum of the length LI of the first section and the length L2 of the second section. In the present case, the first portion 410 has a length LI of 0, 027 mm and the total length L of the injection channel 40 is 0.36 mm.

In this way, an advantageous ratio of the length L2 to the diameter D2 of the second portion 420 of 1.67 is achieved. Compared with injection channels 40 ENT ^¬ expresses this without first portions 410 with the same wall thickness of the wall 20 of a Re ^¬ duzierung the ratio of length to diameter of about 7.3 ~. 6

Preferably, the nozzle body 10 is designed for use in a fluid injection valve 1, which has a relative to the nozzle body 10 movable closing element 15 (not shown in Fig. 1). The movable closing element 15 cooperates with a valve seat 215 on the inner surface 210 of the wall 20 of the nozzle body 10 in order to prevent fluid flow through the injection channels 40 in a closed position of the closing element 15 and to release the fluid flow in other positions. In the closed position, the closing element 15 bears against the valve seat 215. Downstream of the valve seat 250, the closing ^¬ element 15 is not the entire surface of the inner surface 210, but leaves a volume free. This volume, together with the volume of the first sections 410, forms the so-called dead volume or Schad volume. In this Schadvolumen can be located at the end of an injection process fuel, which from

Fluid injection valve 1 can be discharged, although the closing element 15 is in the closed position.

Such a harmful volume is usually unavoidable in the production of the nozzle body. In the present embodiment, the volume bounded by the inner surface 210 upstream of the valve seat 215 and the closing element 15 - in other words, the volume of fluid defined by the wall 20 and the closing element 15 downstream of the valve seat 215 without the injection channels 40 - has a value of 0.04 mm ^. The total volume of the six first sections 410 of the injection ports 40 in the present embodiment has a value of 0.02 mm ^. Thus, the volume of the first portions is half the volume of the inner surface 210 and the closure member 15 downstream of the valve seat 215 limited.

In a variant of the first embodiment, the first sections 410 each have a diameter Dl of 0.35 mm and a length LI of 0.035 mm. The cylindrical second sections have a diameter D2 of 0.15 mm. The ratio of length L2 to diameter D2 of the second sections 420 is then 2.17. Compared with injection channels 40 without first sections 410, this corresponds to a reduction of the ratio of length to diameter by about 9.6% for the same wall thickness of the wall 20.

Figure 2 shows a second embodiment of the invention. In this embodiment of a fluid injection valve 1, the closing element 15 is shown in the closed position, d. H. in contact with the valve seat 215 of the inner surface 210 of the wall 20 of the nozzle body 10. The nozzle body of the second embodiment corresponds substantially to that of the first embodiment.

However, the first portions 410 of the injection holes 40 in the second embodiment have no cylindrical shape, but the shape of truncated cones tapering conically from a first top surface formed by the respective inlet opening 412 to a second top surface formed by the fluid inlet opening of the second section 420 in the transition region 415. With an identical total volume of the first sections, in this way a reduction of the ratio of length L2 to diameter D2 of the second sections 420 relative to injection channels 40 without the first sections 410 of up to approximately 20% can be achieved.

The invention is not limited by the description with reference to the embodiments thereof. Rather, it encompasses any new feature and any combination of features, which in particular includes any combination of features of the execution ^¬ examples and claims.

Claims

Nozzle body (10) for a fluid injection valve (1) - The nozzle body (10) is hollow, so that an inner surface (210) of a wall (20) of the nozzle body (10) defines a blind hole (30),  - The nozzle body (10) has at least one injection channel (40) which penetrates the wall (20) from the inner surface (210) to an outer surface (220) of the wall (20) and a first portion (410) and one of the first Section (410) downstream following second Section (420), the first portion (410) extends from an entrance opening (412) in the inner surface (210) to a transition area (415) and the second portion (420) extends from the transition area (415) to an exit opening (422) in the Exterior surface (220) extends out. characterized in that - The equivalent diameter (Dl) of the inlet opening (412) is at least 1.5 times as large as the equiva ^¬ Lentdurchmesser (D2) of the second section (420) in the transition region (415) and  - The length (LI) of the first portion (410) is between 5% and 15% of the length (L) of the injection channel (40), the limits are included. Is the nozzle body (10) according to the preceding claim, wherein the length of the first portion (410) has a value between 10% and 30% of the value of the equivalent diameter (D2) of the second portion (420) in positive ^¬ transition region (415) with the limits included. Nozzle body (10) according to one of the preceding claims, wherein the equivalent diameter (Dl) of the entrance opening (412) is at most 2.5 times as large as the Äquiva ^¬ lentdurchmesser (D2) of the second portion (420) in the transition region (415). Nozzle body (10) according to one of the preceding claims, wherein the first portion (410) has a cylindrical shape or tapers from the inlet opening (412) to the transition region (415), in particular conically tapered. A nozzle body (10) according to any one of the preceding claims, wherein the second portion (420) has a cylindrical shape or tapers in the direction of the exit opening. Nozzle body (10) according to one of the preceding claims, which has a longitudinal axis (12) and has a plurality of injection channels (40) which are distributed around the longitudinal axis (12) in the wall (20) and in particular from the longitudinal axis (12). are spaced. Nozzle body (10) according to one of the preceding claims, wherein  - The length (L) of the injection channel (40) has a value between 0.3 mm and 0.4 mm and / or  the length (LI) of the first section (410) has a value between 0.025 mm and 0.04 mm and / or  - The equivalent diameter (Dl) of the inlet opening (412) has a value between 0.32 mm and 0.5 mm and / or the equivalent diameter (D2) of the second section (420) in the transition region (415) has a value between 0.1 mm and 0.28 mm, the borders are included. Fluid injection valve (1) having a nozzle body (10) according to any preceding claim, and a movable closing element (15) which cooperates with a valve seat (215) on the other inner surface (210) into a closed ^¬ position in which the shutter (15) on the valve seat (215), to prevent fluid flow through the at least one injection channel (40), and in others Positions to release the fluid flow, wherein the volume of the first portion (410) or, in the case of a plurality of injection channels, the total volume of all the first portions (410), is at most as large and preferably at most half as large as one of the inner surface (210) downstream of the valve seat (215 ) and the closing element (15) limited volume. 9. fluid injection valve (1) according to the preceding An ^¬ claim, wherein the of the inner surface (210) downstream of the valve seat (215) and the closing element (15) be ^¬ limited volume less than or equal to 0.05 mm ^ and / or larger or is equal to 0.03 mm ^. 10. fluid injection valve (1) according to claim 8 or 9, wherein the volume of the first portion (410) or the Ge ^¬ samtvolumen all first portions (410) has a value between 0.015 mm ^ and 0.025 mm ^, including the limits are.