DE102016216608A1 - Two-substance injector for two media - Google Patents

Abstract

The invention relates to a two-substance injector 1, comprising an injector body 2 with an outlet-side end region, with an injector body recess 3 formed in the injector body 2, wherein an external injector needle 4 controlling at least one injector body outlet opening 10 for a second medium in the end region is arranged longitudinally movably in the injector body recess 3 , and wherein in the Injektornadel 4 a Injektornadelausnehmung 5 is arranged, in which at least one Injektornadelaustrittsöffnung 19 for a first medium in the Injektornadel 4 controlling inner Injektornadel 6 is longitudinally movably arranged According to the invention a Zweistoffinjektor 1 is provided, with respect to its function over the prior art is improved. This is achieved in that the injector body outlet opening 10 is arranged in a closed position of the outer Injektornadel 4 in extension of the Injektornadelaustrittsöffnung 19.

Description

The invention relates to a two-substance injector for two media, comprising an injector body with an outlet-side end region, with an injector body recess formed in the injector body, wherein an outer injector needle controlling at least one injector body outlet opening for a second medium in the end region is longitudinally movably arranged in the injector body recess, and wherein the outer injector needle is arranged an injector needle recess in which at least one Injektornadelaustrittsöffnung for a first medium in the outer Injektornadel controlling inner Injektornadel is arranged longitudinally movable.

State of the art

Such a binary injector is from the DE 10 2005 037 954 A1 known. This two-substance injector is designed for a liquid medium and a gaseous medium and has an injector body with an injector body recess, in which an outer injector needle controlling at least one injector body outlet opening in the injector body is arranged longitudinally movably. In this outer Injektornadel Injektornadelausnehmung is arranged in which an inner Injektornadel is arranged longitudinally movable. This inner injector needle controls a number of injector needle orifices located in the outer injector needle.

The invention has for its object to provide a two-fluid injector, which is improved in terms of its function over the prior art.

Disclosure of the invention

This object is achieved in that the injector body outlet opening is arranged in a closed position of the outer Injektornadel in extension of the Injektornadelaustrittsöffnung. This embodiment makes it possible for the first medium controlled by the inner injector needle to pass through the at least one injector needle outlet opening and further through the injector body outlet opening into a working space into which the outlet-side end region of the two-component injector projects. This embodiment avoids disturbances in the propagation of the first medium or the introduction of the first medium into the working space. For example, the first medium forms an ignition jet for the second medium to be subsequently introduced into the working space.

In a development of the invention, the injector body outlet opening is arranged coaxially with the injector needle outlet opening. Thus, the jet of the first medium, which is controlled by the inner injector needle, first passes through the injector needle outlet opening and then to the coaxially arranged injector body outlet opening. In this case, a jet cone angle α of the first medium, which is determined by the injector needle outlet opening, is smaller than a jet angle that is determined by the injector body outlet opening. This embodiment ensures that the jet of the first medium passing through the injector needle outlet opening passes through it without striking or making contact with the injector body outlet opening. As a result, a deflection of the beam of the first medium is avoided. In addition, this avoids that a deposit or scattering of the medium, which is controlled by the inner Injektornadel occurs on the wall of the injector body exit opening. Such deposition or scattering could occur as drops or ligaments. This would adversely affect the function of the binary injector. For example, the medium controlled by the inner injector needle is a liquid medium and the medium controlled by the outer injector needle is a gaseous medium. As a result of the embodiment according to the invention, it is now achieved that the liquid medium takes place as far as possible without influencing the region in the two-component injector in which the gaseous medium is conducted. It should be noted that in the closed position of the outer Injektornadel the corresponding outlet-side end portion of the injector is shut off from a filling with gaseous medium. As a result, no relevant interference parameter influencing the corresponding jet is imposed on the liquid medium. Ideally, the jet passing through the injector needle orifice is formed or formed with respect to the injector body orifice such that it has a clear distance from the injector body orifice forming the inlet and exit from the injector body orifice at a small distance from the wall but without wetting them in this area.

In a further development of the invention, the outer injector needle is rotationally fixed to the injector body. This rotational fixation is important for the function of the two-component injector according to the invention, in that the coaxiality of the injector body outlet opening with the injector needle outlet opening is ensured with high safety in close tolerance limits of, for example, 1 °. In this case, the rotational fixation can basically be designed and arranged as desired.

In a further development of the invention, the outer injector needle on the dome side has a rotationally locking injector needle guide surface cooperating with an injector body guide surface. This is an alternative to, for example, guiding the outer injector needle in a remote location Area to the dome-side end. For example, the Injektorkörperführungsfläche and Injektornadelführungsfläche are formed as a tri-fold in a part of a gas space forming blind hole, the thus formed Injektornadelführung allows fluid exchange between the two sides of the blind hole guide and also has a hydraulic damping effect on impact of the outer Injektornadel in the end positions.

In a further development of the invention, the Injektornadelaustrittsöffnung is at least over an outer partial length conically widening outward. In an alternative embodiment, the Injektornadelaustrittsöffnung is a stepped bore, wherein the larger diameter of the stepped bore is arranged on the outside of the injector body. In a further embodiment, the Injektornadelaustrittsöffnung is designed as a Laval nozzle. All embodiments ensure that the spray of the liquid medium is passed through the Injektornadelaustrittsöffnung so that it then passes freely through the Injektorkörperaustrittsöffnung. It should be noted that basically the described embodiments can be applied mutatis mutandis to the injector body outlet opening.

The injection hole design of the Injektornadelaustrittsöffnung can be selected in one embodiment of the Zweistoffinjektors with a spray hole diameter of 100 microns to 160 microns with a conical blind hole type. For this purpose, the spray hole length of the Injektornadelaustrittsöffnung is maximized to, for example, between 1mm and 1.3 mm. The pitch circle diameter of the (multiple) injector needle orifice (s) is minimized to, for example, between 0.60 mm and 0.9 mm. In this case, each Injektornadelaustrittsöffnung is as deep as possible in the Injektornadelsackloch, which is formed within the Injektornadelkuppe introduced. The dome wall thickness in the region of the injector needle outlet opening is minimized to, for example, between 0.6 mm and 0.9 mm. The taper of the Injektornadelaustrittsöffnung is selected negative (for example, with an outer diameter of 50 microns greater than the theoretical value of the inner diameter, with a cylindrical or slightly conical part of the injection hole contour is desirable up to about 50% of the injection hole length). An elaborate design is the choice of a stepped bore and an ideal shape is the training as a Laval nozzle.

In order to maximize the ratio of the density of the liquid to the density of the gas in an injection, the density of the gas in the blind hole of the gas path should be minimized. A contributor to this is the molecular weight of the gas (at the same pressure and temperature conditions). For this purpose, an early pilot injection of the gas jet should take place, so that at the time of the liquid injection in the gas bag hole and possibly the closer environment of the nozzle there is a high concentration, for example of methane. However, this latter contribution is not necessary when choosing a small spray hole length (e.g., between 0.6 mm and 0.9 mm) and a diameter of> 0.5 mm (e.g., 0.75 mm) of the injector needle exit orifice. It may also be possible to reduce the jet cone angle to less than 10 ° if a diameter of the injector needle outlet opening is chosen to be less than 0.5 mm (and all other measures are insufficient). If, nevertheless, a small proportion of the liquid jet is deposited on the wall of the injector body outlet opening, it can be assumed that the regular injection of gaseous medium under a pressure of greater than 300 bar entrains drops of liquid from the wall of the injector body outlet opening and conveys them into the working space, without that appreciable damage is caused by a fluidically relevant deposit on the wall of the injector body outlet opening (coking).

While the subject matter of the bi-fuel injector of the present invention may be used in any application, there is a preferred use in a fuel injection system on an internal combustion engine wherein the media is a liquid fuel and a gaseous fuel. The liquid fuel is for example diesel fuel and the gaseous fuel for example methane. The diesel fuel is injected in particular at a start of the internal combustion engine in a combustion chamber of the internal combustion engine, during which injection no methane is injected. Only when the internal combustion engine has been put into operation, methane is injected into the combustion chamber and simultaneously terminates the injection of diesel fuel. Such a controlled injection can be implemented with the inventively embodied injector, whereby the operation of the corresponding internal combustion engine is improved by the thus formed injector. This is reflected by a reduction in fuel consumption while reducing (harmful) exhaust emissions. Here, the inventively designed Zweistoffinjektor cost neutral or even cheaper than a conventionally trained Zweistoffinjektor produced.

Further advantageous embodiments of the invention are described in the drawings, are described in more detail in the embodiments illustrated in the figures.

Show it:

1 a schematic sectional view of an inventively designed Zweistoffinjektors,

2 a perspective detailed view of an injection-side end portion of a Zweistoffinjektors according to 1 .

3 a sectional view through a spritzseitigen end according to 2 .

4 a sectional view through an injector needle outlet,

5 a sectional view of a Zweistoffinjektors in an alternative embodiment and

6 a detailed view of a two-fluid injector according to 5 ,

The in 1 shown Zweistoffinjektor 1 is part of a fuel injection system of an internal combustion engine, wherein with the binary injector 1 for operating the internal combustion engine two different media, namely a first liquid fuel, preferably diesel fuel, and a second gaseous fuel, preferably fuel gas in the form of methane, alternately or additively injected into a combustion chamber of the internal combustion engine.

The binary injector 1 has an injector body 2 in which an injector body recess 3 for an external injector needle 4 is admitted. The outer injector needle 4 has an inner Injektornadelausnehmung 5 for an internal injector needle 6 on. The outer injector needle 4 has an injector needle seat 7 up in a valve seat 8th of the injector body 2 acts. To the injector needle seat 7 Closes end of an injector needle 9 in, in the area in front of the injector needle seat 7 at least one Injektornadelaustrittsöffnung 19 is admitted. To this Injektornadelaustrittsöffnung 19 is in a closed position of the outer Injektornadel 4 in which the injector needle seat 7 in a valve seat 8th acting coaxially in the injector body 2 an injector body exit opening 10 arranged. This embodiment forms the core of the invention and will be explained in more detail below.

The injector body outlet opening 10 is permanently with a gas space 12 connected between the injector needle point 9 and the injector body 2 at the end in front of the valve seat 8th is arranged.

When from one opposite to the Injektornadelkuppe 9 arranged Injektornadelfeder 11 set or effected Aufsitzen the Injektornadelsitzes 7 in the valve seat 8th is a connection of the gas space 12 with one in the injector body 2 taken in gas channel 13 prevented. The gas channel 13 is with one on the injector body 2 attached gas line 14 connected via the into the gas channel 13 Fuel gas is introduced, with open external Injektornadel 4 So if the injector needle seat 7 from the valve seat 8th is lifted off, in the gas space 12 passes and through the Injektorkörperaustrittsöffnung 10 is injected or injected into the combustion chamber of the internal combustion engine.

The in the inner Injektornadelausnehmung 5 guided inner injector needle 6 also has an injector needle point 15 on that in a valve seat 16 in the outer injector needle 4 is incorporated, acts. In the illustrated closed position of the inner Injektornadel 6 or their Injektornadelspitze 15 is the at least one in the outer Injektornadel 4 taken in Injektornadelaustrittsöffnung 19 locked. Is the inner injector needle 6 and thus the Injektornadelspitze 15 against a needle spring 18 displaced axially upward, which is at least one Injektornadelaustrittsöffnung 19 via a fluid space 17 and continue through the injector needle recess 5 with a fluid channel 20 and one on the injector body 2 attached fluid line 21 connected. Through the fluid line 21 becomes the binary injector 1 Diesel fuel supplied, with open internal Injektornadel 6 through the at least one Injektornadelaustrittsöffnung 19 through the fluid space 17 through and further through the injector body exit opening 10 is injected into the combustion chamber of the internal combustion engine. To ensure unimpeded injection, the outer injector needle is 4 opposite the injector body 2 rotationally fixed, that is, it can be moved axially, but not twisted.

As a result, the permanent coaxial arrangement of the injector body outlet opening 10 to the Injektornadelaustrittsöffnung 19 ensured. The rotational fixation takes place in the embodiment according to 1 for example, in the upper region of the outer Injektornadel 4 opposite the injector body 2 ,

In the illustrated embodiment, the adjustment of the outer Injektornadel 4 and the inner injector needle 6 of two independently controllable valve elements 22a . 22b controlled. The valve elements 22a . 22b For example, be electromagnetic, hydraulic or mechanical actuators 23a . 23b driven. The valve element 22a acts with a first control line 24a together, the fluid line 21 with an injector needle spring 11 receiving injector needle spring space 25 and the valve element 22a combines. Is the first valve element 22a in the illustrated closed position, is a connection between the first control line 24a and one also on the injector body 2 attached return line 26 interrupted. This builds up in the injector needle spring space 25 a fluid pressure which, together with the injector needle spring 11 the outer injector needle 4 in the closed position. If, however, the flow connection between the first control line 24a and the return line 26 from the valve element 22a released, there is a pressure reduction in the Injektornadelfederraum 25 and the outer injector needle 4 is by the at one in the gas space 12 arranged pressure shoulder axially displaced gas pressure, so that through the at least one Injektorkörperaustrittsöffnung 10 Fuel gas is injected into the combustion chamber. The same operation applies mutatis mutandis to the inner Injektornadel 6 coming from the valve element 22b and a second control line 24b is controlled. In the two control lines 24a . 24b are control line reactors 26a . 26b used the inflow of diesel fuel into the control lines 24a . 24b limit or mutual influence of the control function by the two valve elements 22a . 22b prevent. The described control is exemplary and other embodiments are possible.

2 shows a perspective detail view of a spritzseitigen end portion of a two-fluid injector 1 according to 1 , In concrete terms, the injection-side end region of the injector body is shown 2 with the recessed and distributed over the circumference arranged Injektorkörperaustrittsöffnungen 10 with indicated diesel beams 27 passing through the injector body orifices 10 be injected into the combustion chamber of the internal combustion engine. For example, seven to ten injector body outlet openings 10 on the circumference of the injector body 2 arranged distributed and the diesel beams 27 are injected with a diesel injection pressure of for example 300 bar to 600 bar in the combustion chamber of the internal combustion engine.

3 shows a sectional view through an injection-side end portion of the injector body 2 according to 2 with a cut injector body exit opening 10 through which a diesel steel 27 passes through. Behind this is an adjacent injector body exit opening 10 with a diesel jet passing through it 27 shown. The diesel beams 27 be through the Injektornadelaustrittsöffnungen not shown here 19 shaped and traverse the gas space 12 before entering the respective Injektorkörperaustrittsöffnung 10 enter. Here, the steel cone angle α by appropriate design of the Injektornadelaustrittsöffnung 19 (please refer 1 ) so shaped or so small that a deposition or scattering of the diesel fluid on the wall of the injector body outlet openings 10 is avoided. For example, the design of the appropriate aperture geometry parameters and the advantageous operating constraints for such injection iteratively occurs between a simulation and a design. The from the injector body outlet openings 10 escaping diesel jet 27 happens the Injektorkörperaustrittsöffnungen 10 at the outer edge, just a short distance from the wall. The injector body outlet openings 10 are cylindrical, for example, and this is the easiest way through a corresponding hole implementable design. The injector body outlet openings 10 But can also have a conical widening contour at least over a partial length, especially in the outer region. Also, the configuration of the injector body outlet openings 10 in the form of a Laval nozzle within the scope of the invention conceivable or possible.

In the sectional view according to 4 through an injector needle outlet opening 19 this is designed as a stepped bore, wherein the larger diameter of the stepped bore outside of the outer Injektornadel 4 is arranged. Such a stepped bore can be eroded, for example.

The sectional view and the detailed view according to the 5 and 6 show a structurally alternative embodiment to a two-component injector 1 according to 1 , but with respect to the basic description to the description of the figures 1 is referenced. In this embodiment, the outer Injektornadel 4 on the dome side one with an injector body guide surface 28 cooperating injector needle guide surface 29 on, which is a twisting of the outer injector needle 4 opposite the injector body 2 prevented. For example, the injector body guide surface 28 and injector needle guide surface 29 as dreiflach in the one part of the gas space 12 formed blind hole, wherein the Injektornadelführung formed thereby allows the fluid exchange between the two sides of the blind hole guide and also a hydraulic damping effect upon impact of the outer Injektornadel 4 has in the end positions.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005037954 A1 [0002]

Claims (10)

Bi-substance injector ( 1 ), comprising an injector body ( 2 ) with an outlet-side end region, with one in the injector body ( 2 ) formed Injektorkörperausnehmung ( 3 ), wherein in the Injektorkörperausnehmung ( 3 ) an at least one injector body outlet opening ( 10 ) for a second medium in the end region controlling outer Injektornadel ( 4 ) is longitudinally movably arranged, and wherein in the Injektornadel ( 4 ) an injector needle recess ( 5 ) is arranged, in the at least one Injektornadelaustrittsöffnung ( 19 ) for a first medium in the injector needle ( 4 ) controlling inner Injektornadel ( 6 ) Is arranged longitudinally movably characterized in that the Injektorkörperaustrittsöffnung ( 10 ) in a closed position of the outer Injektornadel ( 4 ) in extension of the Injektornadelaustrittsöffnung ( 19 ) is arranged. Bi-substance injector ( 1 ) according to claim 1, characterized in that the injector body outlet opening ( 10 ) coaxial with the Injektornadelaustrittsöffnung ( 19 ) is arranged. Bi-substance injector ( 1 ) according to claim 1 or 2, characterized in that one of the Injektornadelaustrittsöffnung ( 19 ) fixed beam cone angle α of the first medium smaller than one of the injector body outlet opening ( 10 ) is certain beam cone angle. Bi-substance injector ( 1 ) according to one of the preceding claims, characterized in that the outer injector needle ( 4 ) rotationally fixed to the injector body ( 2 ). Bi-substance injector ( 1 ) according to claim 4, characterized in that the outer injector needle ( 4 ) on the dome-side one with an injector body guide surface ( 28 ) cooperating Injektornadelführungsfläche ( 29 ) having. Bi-substance injector ( 1 ) according to one of the preceding claims, characterized in that the Injektornadelaustrittsöffnung ( 19 ) is conically widening outward over at least an outer partial length. Bi-substance injector ( 1 ) according to one of the preceding claims, characterized in that the Injektornadelaustrittsöffnung ( 19 ) is a stepped bore, and that the larger diameter of the stepped bore outside of the injector body ( 2 ) is arranged. Bi-substance injector ( 1 ) according to one of the preceding claims, characterized in that the Injektornadelaustrittsöffnung ( 19 ) is designed as a Laval nozzle. Bi-substance injector ( 1 ) according to one of the preceding claims, characterized in that the Injektornadelaustrittsöffnung ( 19 ) in the region of a Injektornadelkuppe ( 9 ) of the outer injector needle ( 4 ) is arranged. Bi-substance injector ( 1 ) according to one of the preceding claims for use in a fuel injection system on an internal combustion engine with media in the form of a first liquid fuel and a second gaseous fuel.

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