Injector and mechanism having the injector

Abstract

The present invention relates to an injector (10) for discharging a working medium under pressure into a combustion chamber (1) of an internal combustion engine (2). [Solution] The injector has an injector housing (22) in which a nozzle needle (34) is arranged so as to be able to slide longitudinally between a closed position in which it closes at least one inlet opening (26) for the working medium to the combustion chamber (1) and an open position in which it releases the at least one inlet opening (26), a pressure chamber (28) for the working medium arranged in the injector housing (22), and a control chamber (46) arranged in the injector housing (22) which can be filled with a control medium different from the working medium under pressure.

Description

[Technical Field]

[0001] The present invention relates to an injector for discharging a working medium under pressure into a combustion chamber of an internal combustion engine, in particular for injecting alternative fuels, such as ammonia or alcohols such as ethanol or methanol, in which the stroke movement of a nozzle needle is initiated via a control medium different from the working medium. [Background technology]

[0002] The applicant's patent application JP 2004-102269 discloses an injector having the features of claim 1. This injector is characterized by having two pressure chambers, each of which can be filled with a different medium, in which a nozzle needle is arranged so as to be able to perform a stroke movement. The two pressure chambers are separated from each other in a medium-tight manner by a bellows extending transversely to the longitudinal direction of the nozzle needle. The pressure chamber facing the inlet opening of the injector can be filled with a control medium for influencing the longitudinal movement of the nozzle needle, while the pressure chamber facing the inlet opening can be filled with a working medium that can be discharged from the injector via the inlet opening. It is important that when both pressure chambers are not filled with a medium under pressure, no force acting on the nozzle needle in the closing direction of the nozzle needle to close the inlet opening is generated.

[0003] Another injector from the state of the art is known from the applicant's patent application DE 10 02 04 199 A1, which also does not bias the nozzle needle in the direction of the position closing the inlet opening when the control chamber is not biased by the (hydraulic) pressure of the control medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] German Patent Application Publication No. 102017217991 [Patent Document 2] German Patent Application Publication No. 102018211510 Summary of the Invention

[0005] The injector according to the invention for discharging a working medium under pressure into a combustion chamber of an internal combustion engine having the features of claim 1 has the advantage that when the control chamber is not hydraulically biased by the pressure of the control medium, the nozzle needle is biased into a closed position, thereby sealing off the pressure chamber filled with working medium from the combustion chamber.

[0006] In particular, the injector according to the invention makes it possible to generate a relatively high closing force acting on the nozzle needle in the direction of the closed position. This is particularly advantageous when the injector is installed together with another injector for discharging or injecting a working medium into a combustion chamber, where the injector according to the invention injects, for example, ammonia or an alcohol such as ethanol or methanol into the combustion chamber, and the other injector is designed, in particular, to inject diesel fuel. It is important in this case that when the other injector is in an operating state for injecting (diesel) fuel into the combustion chamber and the injector according to the invention is pressureless or deactivated, the combustion chamber pressure created by the operation of the other injector does not result in combustion chamber gases being able to enter the injector according to the invention, which could potentially damage the injector.

[0007] In other words, this means that when the internal combustion engine is operating with the other injector, the closing force that can be generated by at least one closing spring on the nozzle needle in the injector of the present invention is at least as great as the combustion chamber pressure, thereby keeping the nozzle needle in the closed position.

[0008] In the injector according to the invention, therefore, in the context explained above, the nozzle needle is linked to at least one closing spring, in particular arranged in abutting contact with the at least one closing spring, which is intended to bias the nozzle needle by means of a spring force in the direction of the closed position.

[0009] Preferred developments of the injector according to the invention for discharging a working medium under pressure into the combustion chamber of an internal combustion engine are set forth in the dependent claims.

[0010] With respect to typical combustion chamber pressures when an (additional or second) injector configured for injecting liquid fuel or (diesel) fuel into a combustion chamber is used, it is intended that the nozzle needle, viewed in the direction of its longitudinal axis, is guided radially in a guide area of ​​the injector housing between a pressure chamber for the working medium and a control chamber for the control medium, the pressure of the control medium in the control chamber acts on a control surface arranged perpendicular to the longitudinal axis of the nozzle needle, the nozzle needle abuts against a wall area of ​​the pressure chamber forming a sealing seat when in the closed position, the area of ​​the nozzle needle in the area of ​​the sealing seat corresponds to a maximum of 41% of the area of ​​the area of ​​the guide area, and the area of ​​the control surface corresponds to between 23% and 74% of the area of ​​the area of ​​the guide area.

[0011] In order to generate a force acting in the opening direction of the nozzle needle to release the inlet opening when the pressure in the control chamber drops, the nozzle needle is intended to have a pressure surface in the pressure chamber for the working medium that is configured to generate a force acting in the opening direction on the nozzle needle under the pressure of the hydraulic pressure of the working medium.

[0012] Another particularly preferred design embodiment of the injector provides for the nozzle needle to have a radially surrounded area in the control chamber by a guide sleeve, which is biased by a first closing spring towards the component that defines the control chamber. This type of embodiment makes it possible to arrange a second closing spring, which is provided in particular for generating a relatively high closing force on the nozzle needle, outside the control chamber in a separate spring chamber, which is sealed off from this other chamber (spring chamber) by the guide sleeve.

[0013] A preferred development of the proposal just mentioned provides that the component against which the guide sleeve abuts (sealingly) is a throttle plate.

[0014] As already mentioned above, it is a particular advantage that the second closing spring is arranged in a spring chamber separate from the low-pressure region and is configured to bias the nozzle needle towards the closed position with a higher force than the first closing spring. In particular, a design embodiment of this kind allows the second closing spring to have almost any size or shape and geometry, so that the size of the control chamber is not adversely affected or does not have to be enlarged.

[0015] To allow for additional sealing between the control medium in the control chamber and the working medium in the pressure chamber, a groove may be formed in the region of the guide area for the nozzle needle, which groove runs radially around the longitudinal axis of the nozzle needle and can be filled with a sealing medium, which may be, for example, a sealing oil with a relatively high viscosity, so that the sealing medium is less likely to mix with the working medium or the control medium.

[0016] The present invention also includes a mechanism for discharging a working medium into a combustion chamber of an internal combustion engine, the mechanism having a first injector as described above and a second injector configured to inject a working medium different from that of the first injector into the combustion chamber, the combustion chamber pressure being at most approximately 350 bar when the internal combustion engine is operated by the second injector.

[0017] The mechanism is very particularly preferably intended to be configured for discharging an alternative fuel as working medium, such as ammonia or an alcohol, such as ethanol or methanol, for the first injector and diesel fuel for the second injector into the combustion chamber of an internal combustion engine.

[0018] Other advantages, features, and particulars of the present invention will become apparent from the following description of preferred embodiments of the invention and by reference to the drawings. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing the arrangement of two injectors in the region of the combustion chamber of an internal combustion engine; [Figure 2] 1 is a simplified longitudinal section showing an injector for discharging a working medium, in particular a liquid, into a combustion chamber of an internal combustion engine; DETAILED DESCRIPTION OF THE INVENTION

[0020] The same elements or elements with the same functions are designated by the same reference numerals in the various drawings.

[0021] 1 shows an arrangement 100 for discharging, injecting or injecting different working media into a combustion chamber 1 of an internal combustion engine 2, with two injectors 10, 20 provided in the region of the combustion chamber 1 of the internal combustion engine 2. In particular, the first injector 10 is configured for injecting a first working medium, in particular an alternative fuel such as ammonia or an alcohol such as ethanol or methanol, stored in a storage reservoir 12 into the combustion chamber 1, whereas the other injector 20 is configured for injecting a second working medium, in particular diesel fuel, stored in a second storage reservoir 14 into the combustion chamber 1.

[0022] It is also important to note that both injectors 10, 20 can be operated together, especially if the other injector 20 serves as an ignition source for ignition of the working medium of the first injector 10. However, the first injector 10 can also be switched off if necessary, for example, if the first working medium is not available. In such a case, the internal combustion engine 2 is operated solely by the other second injector 20.

[0023] 2 in more detail has an injector housing 22 in which a recess 24 is formed with several areas of different diameters. On the side facing the combustion chamber 1, the injector housing 22 has several inlet openings 26 designed for injecting a (gaseous) working medium into the combustion chamber 1 of the internal combustion engine 2. To this end, the recess 24 on the side facing the inlet openings 26 forms a pressure chamber 28 which is connectable with the working medium under pressure via a feed hole 30.

[0024] A nozzle needle 34 is arranged in the recess 24 so as to be capable of stroke movement in the direction of the longitudinal axis 32. In the closed position shown in Figure 2, a tapered nozzle needle end 35 rests against the recess 24, forming a sealing seat 38 in the region of a wall section 36 of the recess 24, thereby at least indirectly closing the inlet opening 26. The nozzle needle 34 also has a section of different diameters within the pressure chamber 28, so that a pressure surface 39, which is tapered in this example, generates an opening force on the nozzle needle 34 that releases the inlet opening 26 when the pressure chamber 28 is hydraulically pressurized by the working medium.

[0025] In its longitudinally intermediate region, the nozzle needle 34 is radially guided in a guide section 40 of the recess 24. The nozzle needle 34 or the guide section 40 has a constant diameter D in the region of the guide section 40. Furthermore, in approximately the central region of the guide section 40, an annular groove 42 is formed in the region of the wall of the recess 24, which runs radially around the longitudinal axis 32 and can be filled with a sealing medium, such as sealing oil, via a supply channel 44. If the injector 20 is configured as a diesel injector, the sealing medium or sealing oil can be taken from the fuel circuit of the injector 20, i.e., the sealing medium can be diesel.

[0026] On the side facing away from the inlet opening 26, the nozzle needle 34 projects with a reduced diameter section 45 into a control chamber 46, also formed in the recess 24. The control chamber 46 is connected via an inlet opening 48 to a storage reservoir 49 for a control medium under pressure, which is a medium different from the working medium. Furthermore, the control chamber 46 can be vented via an outlet opening 50 to a low-pressure region 52. For this purpose, a valve 54 is used, which allows the control medium to escape from the control chamber 46 when in the open position. The valve 54 is known per se in the prior art and will not be described in detail, but can be operated, for example, by a magnetic actuator.

[0027] The control chamber 46 or recess 24 is closed on the side facing the inlet opening 26 by a throttle plate 55, which forms an inlet throttle 56 for the inlet channel 44 and an outlet throttle 57 for the outlet bore 50. Furthermore, the throttle plate 55 has a through-hole 58 concentrically with the longitudinal axis 32 on the side facing the control chamber 46, which opens into a spring chamber 60.

[0028] Within the control chamber 46, the section 45 of the nozzle needle 34 acting as a guide section is radially surrounded by a guide sleeve 62 which serves to seal the through-bore 58 in the direction of the spring chamber 60. For this purpose, the guide sleeve 62, which has a tapered sealing edge 63 on its side facing the throttle plate 55 and which runs radially around the longitudinal axis 32, is biased towards the throttle plate 55 by the spring force of a first closing spring 64. The first closing spring 64 bears against the nozzle needle 34 in the region of an annular control surface 65 running around the longitudinal axis 32.

[0029] The nozzle needle 34 extends through the through-bore 58 with a section 66 which is expanded in diameter in the region of the spring chamber 60 in the shape of a dish and then reduced in diameter. A second closing spring 68 is arranged in the spring chamber 60 and is characterized in that this second closing spring is supported against a component fixed to the housing (not shown) of the injector 10 and biases the nozzle needle 34 towards the sealing seat 38 with a spring force higher than that of the first closing spring 64.

[0030] To discharge the working medium into the combustion chamber 1 of the internal combustion engine 2 by the injector 10, the pressure chamber 28 is filled with working medium (gas) under high pressure. To lift the nozzle needle 34 from the closed position shown in FIG. 2 to the open position, in which the working medium can flow into the combustion chamber 1 via the inlet opening 26, the pressure in the control chamber 46 must be reduced. This is achieved by actuating a valve 54, which allows the control medium to flow into the low-pressure chamber 52. The opening force required to open the nozzle needle 34 is generated by the working medium acting in the pressure chamber 28 against the pressure surface 39 of the nozzle needle 34.

[0031] In order to close the nozzle needle 34, the closure of the valve 54 causes an increase in hydraulic pressure in the control chamber 46, which generates an (additional) hydraulic closing force in the direction of the closed position of the nozzle needle 34, and the spring force of both closing springs 64 and 68, together with the hydraulic closing force of the control medium in the control chamber 46, must be higher than the force acting on the nozzle needle 34 at the pressure surface 39 in the opening direction by the working medium in the pressure chamber 28.

[0032] What is more important is that when the injector 10 is not activated, in particular when the internal combustion engine 2 is operated with a liquid (gasoline) fuel or working medium by the second injector 20, the nozzle needle 34 is kept in the closed position against the combustion chamber pressure occurring in the combustion chamber 1, which can typically be up to approximately 350 bar, and this is made possible by the spring forces of both closing springs 64, 68. In view of the above-mentioned maximum combustion chamber pressure, the area A of the nozzle needle 34 in the region of the sealing seat 38 S is the area A in the region of the guide diameter or guide area 40 of the nozzle needle 34 F , which corresponds to a maximum of 41% of the area A of the area 66 at the height of the control surface 65. St is the area A in the region of the guide diameter or guide area 40 of the nozzle needle 34 F It has been found that a value between 23% and 74% of the

[0033] The injector 10 described above can be modified or improved in many ways without departing from the inventive concept thereof. [Explanation of symbols]

[0034] 1. Combustion chamber 2. Internal combustion engine 10 First injector 20 Second injector 22 Injector housing 28 Pressure Chamber 26 Inlet opening 32 Long axis 34 Nozzle needle 46 wall area 38 Sticker Sheet 40 Guidance Area 42 Groove 45 areas 46 Control Room 52 Low pressure area 54 Control valve 55 Aperture plate 60 Low-pressure chamber 62 Guide sleeve 64,68 Closing spring 65 Control Surface 68 Second closing spring 100 mechanisms

Claims

1. 1. An injector (10) for discharging a working medium under pressure into a combustion chamber (1) of an internal combustion engine (2), comprising: an injector housing (22) in which a nozzle needle (34) is arranged so as to be longitudinally slidable between a closed position in which at least one inlet opening (26) for the working medium to the combustion chamber (1) is closed and an open position in which the at least one inlet opening (26) is released; a pressure chamber (28) for the working medium arranged in the injector housing (22); and a control chamber (46) arranged in the injector housing (22) which can be filled with a control medium under pressure and different from the working medium, the pressure of the control medium urging the nozzle needle (34) toward the closed position, the control chamber (46) being pressure-relievable via a control valve (54) to a low-pressure region (52), and the pressure chamber (28) and the control chamber (46) being hydraulically separated from each other. the nozzle needle (34) is arranged in abutting contact with at least one closing spring (64, 68), the at least one closing spring (64, 68) biasing the nozzle needle (34) toward a closed position with a spring force; the at least one closing spring (64, 68) includes a first closing spring (64) and a second closing spring (68); The first closing spring (64) is disposed in the control chamber (46), and the second closing spring (68) is disposed in a spring chamber (60) outside the control chamber (46); the nozzle needle (34) has a region (45) in the control chamber (46) that is radially surrounded by a guide sleeve (62); the guide sleeve (62) is biased by the first closing spring (64) towards the components that delimit the control chamber (46); The injector is characterized in that the second closing spring (68) biases the nozzle needle (34) toward the closed position with a force higher than that of the first closing spring (64).

2. The nozzle needle (34) is guided radially in a guide area (40) of the injector housing (22) between the pressure chamber (28) for the working medium and the control chamber (46) for the control medium, as viewed in the direction of its longitudinal axis (32), the pressure of the control medium in the control chamber (46) acting against a control surface (65) arranged perpendicular to the longitudinal axis (32) of the nozzle needle (34), and the nozzle needle (34) has a sealing seat (65) when in the closed position.

2. The injector according to claim 1, wherein the control surface abuts against the wall section of the pressure chamber forming a sealing seat, the area of ​​the nozzle needle in the area of ​​the sealing seat representing at most 41% of the area of ​​the nozzle needle in the area of ​​the guide section, and the area of ​​the control surface representing between 23% and 74% of the area in the area of ​​the guide section.

3. 2. The injector according to claim 1, wherein the nozzle needle has a pressure surface in the pressure chamber for working medium, the pressure surface being configured to generate a force on the nozzle needle under hydraulic pressure of the working medium, which acts on the nozzle needle towards an open position, freeing the at least one inlet opening.

4. 3. The injector according to claim 2, wherein the nozzle needle has a pressure surface in the pressure chamber for working medium, the pressure surface being configured to generate a force on the nozzle needle under hydraulic pressure of the working medium, which acts on the nozzle needle towards an open position, freeing the at least one inlet opening.

5. 2. Injector according to claim 1, characterized in that the component is configured as a throttle plate (55).

6. 5. The injector according to claim 2 or 4, characterized in that in the region of the guide section (40) a groove (42) is formed which circumferentially extends radially around the longitudinal axis (32) and which can be filled with a sealing medium.

7. 10. A mechanism (100) for discharging a working medium into the combustion chamber (1) of an internal combustion engine (2), comprising a first injector (10) according to any one of claims 1 to 5 and a second injector (20) configured for injecting a working medium different from that of the first injector (10) into the combustion chamber (1), wherein the combustion chamber pressure when the internal combustion engine (2) is operated by the second injector (20) is at most 350 bar.

8. 8. The arrangement according to claim 7, characterized in that the first injector (10) is configured for discharging into the combustion chamber (1) an alternative fuel as a working medium, such as ammonia or an alcohol, such as ethanol or methanol, and the second injector (20) for discharging into the combustion chamber (1) a diesel fuel as a working medium.

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