Gas injector for an internal combustion engine

Abstract

The present invention relates to a gas injector (10) for an internal combustion engine (100), comprising: - a first valve (12) and a second valve (14), wherein the first valve (12) and the second valve (14) form a detachable connection (11) with each other at least temporarily, - a control unit (34), wherein the control unit (34) is configured to control the first valve (12) according to a first control profile (13), - wherein the control unit (34) is configured to control the second valve (14) using a second control profile (15).

Description

State of the art

[0001] The present invention relates to a gas injector for an internal combustion engine and a vehicle.

[0002] Currently, there are a variety of different solutions for injecting fluids into combustion chambers of internal combustion engines. Due to the increasing demands on the injection process and the tightening of emission limits, the need for innovative and robust methods for injecting fluids into internal combustion engines is continuously growing.

[0003] The constant weight reduction in the vehicle sector to reduce fuel consumption as well as increasing competition are creating cost pressure, so that cheaper and more efficient components for vehicles are in greater demand. Disclosure of the invention

[0004] The gas injector according to the invention for an internal combustion engine with the features of claim 1 has the advantage over known ones that very high magnetic forces are possible, even without the use of special materials such as FeCo, despite limited shaft diameters. Furthermore, the gas injector can be used to provide a novel control concept for braking the nozzle needle. The gas injector can function as an electric damper, eliminating the need for hydraulic or pneumatic damping. Furthermore, the gas injector has the advantage that costs can be reduced due to the reduced injector length.

[0005] This is achieved according to the invention in that the gas injector for an internal combustion engine has a first valve and a second valve. The first valve and the second valve form a detachable connection with each other, at least temporarily. Furthermore, the gas injector has a control unit, wherein the control unit is configured to control the first valve based on a first control profile, and the control unit is configured to control the second valve based on a second control profile.

[0006] In other words, the gas injector has two valves which can be controlled or deflected independently of one another by the control unit using the two control profiles. By individually adapting the control profile on the first valve as well as the second valve, the nozzle needle can be decelerated using a type of electric damper, eliminating the need for hydraulic or pneumatic damping. In particular, the movement of the closure element, such as a nozzle needle of the gas injector, can be divided into two phases. In the first phase, the first valve is active together with the second valve to move or deflect the closure element and the second valve. In the second phase, only the second valve is moved or deflected to bring the closure element into the desired position for injection.In particular, the second valve can be firmly connected to a nozzle needle, for example by means of a welding process or the like, in order to be able to form the closure element. Both the first valve and the second valve can have a separate coil. In particular, the valves can have the same valve stroke or different valve strokes from one another. The valve strokes can be specifically adjusted, in particular by means of the first control profile and the second control profile. Furthermore, the valve can drive a first armature, in particular based on the first control profile, and the second valve can drive a second armature, in particular based on the second control profile. The connection between the first valve and the second valve can be formed, in particular, at the tips of the first and second armature.More preferably, the first armature presses on the second armature, in particular in the first phase, so that the closure element of the gas injector can be deflected. More preferably, a pole tube can be arranged around both the first valve and the second valve. In addition, a return spring can preferably be arranged on the first valve. In this case, a nozzle spring of the gas injector can act in particular on the second valve or the second armature, so that when the at least temporary connection between the first armature and the second armature exists, the force of the nozzle spring can also be transmitted to the first valve or the first armature. In particular, the nozzle needle can be arranged on the second valve, which blocks and / or releases the injection of the fluid into the combustion chamber.

[0007] The subclaims show preferred developments of the invention.

[0008] Preferably, the first control profile differs from the second control profile at least temporarily.

[0009] An advantage of this design is that the first valve can be controlled independently of the second valve. This allows the gas injector's injection processes to be specifically adjusted and energy to be saved.

[0010] Preferably, the control unit is configured to keep the first control profile and / or the second control profile substantially constant for a first predetermined period of time in order to brake a nozzle needle of the gas injector.

[0011] An advantage of this embodiment is that hydraulic or pneumatic damping in the gas injector can be dispensed with, as this can be achieved by appropriate control using the first and second control profiles. The first control profile and the second control profile can optionally be designed such that the two coils of the first and second valves have essentially the same current path. The two coils can have the same current level, but slightly different voltage levels depending on the coil temperature. The first control profile and the second control profile can have four current phases, in particular boost current, pull-in current, holding current and / or closing current. The fourth current phase can serve to brake the nozzle needle. In this phase, the second valve already begins to close. The first valve remains at the lower stroke stop in this current phase.The level of the closing current can be used to adjust both the closing speed of the nozzle needle and the braking force at the initial contact of the two valves.

[0012] Further preferably, the control unit is configured to adapt a closing speed of the gas injector by adapting the first control profile and / or the second control profile.

[0013] An advantage of this embodiment is that by generating a short, constant current at the first and second valves using the first and second control profiles, the speed of the nozzle needle can be reduced or decelerated. In particular, the first control profile and the second control profile can have a constant value for the applied current for a predetermined period of time, thus being able to control the speed as well as increase or decrease the speed of the nozzle needle.

[0014] Preferably, the control unit is configured to reduce a voltage at the first valve and / or the second valve to substantially zero in order to reduce the closing speed of the gas injector.

[0015] An advantage of this embodiment is that the essentially zero voltage allows for a slow reduction in the magnetic force, thus enabling a greater braking effect of the gas injector. Essentially zero specifically means a value of approximately 0 ± 50% of the gas injector's reference voltage, but especially within typical vibration tolerances.

[0016] Preferably, the first control profile and the second control profile differ at least for a second predetermined period of time.

[0017] An advantage of this embodiment is that greater flexibility can be achieved in controlling, in particular, the valve dynamics and in the design of the electrical damping. The first control profile can, in particular, apply a different current to the first and second valves for a predetermined period of time, thus creating a different control profile.

[0018] Further preferably, the control unit is configured to reduce a current at the first valve for the second predetermined period by adapting the first control profile.

[0019] An advantage of this embodiment is that the energy requirement of the gas injector can be reduced, since for the duration that there is no connection between the first valve and the second valve, the current level at the first valve can be reduced for this duration by means of an adaptation of the first control profile.

[0020] Further preferably, the control unit is configured to reduce a current at the second valve by adapting the second control profile and / or to set it substantially to zero when the first valve and the second valve form a connection when the gas injector is closed.

[0021] An advantage of this design is that the valve dynamics can be configured as desired by adjusting the second control profile. When the first and second valves close, the current at the second profile can be significantly reduced or even reduced to zero using the second control profile, thus ensuring rapid closing. As soon as the second valve is in contact with the first valve, the further closing process is controlled by the first control profile.

[0022] Further preferably, the control unit is configured to adjust a current applied to the second valve by means of the second control profile in order to adjust a valve stroke of the second valve.

[0023] An advantage of this embodiment is that by adjusting or decreasing the flow, purging and late injection and / or partial load operation can be enabled. Further preferably, by reducing the flow in the second flow profile, a floating state can be achieved for the second valve. In the floating state, the stroke of the second valve is determined by the stroke of the first valve.

[0024] Further preferably, the gas injector comprises a sensor unit for monitoring a current and a voltage at the first valve and / or at the second valve, wherein the control unit is configured to adapt the first control profile and / or the second control profile by means of the sensor unit.

[0025] An advantage of this embodiment is that temperature changes or other environmental influences on the gas injector can be taken into account in the control of the first and second valves by adapting the first control profile and the second control profile.

[0026] Preferably, a magnetic separating plate is arranged between the first valve and the second valve.

[0027] An advantage of this embodiment is that magnetic stray fluxes between the first and second valves, which can negatively influence the valve dynamics of both valves, are suppressed. The magnetic separating plate can be arranged, in particular, between a pole tube of the first valve and a pole tube of the second valve. Further preferably, the armature of both the first valve and the second valve can engage in a recess of the magnetic separating plate, thus enabling the movement of the first valve to be transmitted to the second valve.

[0028] Further preferably, the first valve has a first valve stroke, wherein the second valve has a second valve stroke, wherein the second valve stroke is substantially greater than the first valve stroke.

[0029] An advantage of this embodiment with the double magnets, in particular the first and the second valve, is that the total magnetic force of the two valves corresponds to the addition of the two forces and is higher than in the conventional injector design with one valve and thus a relatively smaller shaft diameter is sufficient.

[0030] Preferably, the first valve and the second valve can have different dimensions in order to make optimal use of the limited installation space on the engine.

[0031] Preferably, the two valves, the first and the second valve, have the same dimensions, so that the magnetic force of the first valve is higher due to the smaller valve stroke compared to the valve stroke of the second valve.

[0032] An advantage of this design is that a large working pressure range and purge pressure is possible without pressure equalization or further measures.

[0033] Further preferably, the gas injector has a fluid-conducting channel which is spaced apart from the first valve and the second valve in a substantially fluid-separating manner.

[0034] An advantage of this design is that the fluid flow of the gas injector does not have to flow through the valves, but can be directed through a separate channel.

[0035] Further preferably, the closure element of the gas injector is a flat anchor or a plunger anchor.

[0036] Further preferably, a coil and an armature of the first valve and the second valve are substantially the same.

[0037] An advantage of this embodiment is that the manufacturing costs of the gas injector can be further reduced.

[0038] Preferably, the second valve lift is substantially twice the first valve lift.

[0039] Further preferably, the second valve is integrally connected to a nozzle needle of the closure element.

[0040] A further aspect of the invention relates to a vehicle having a gas injector as described above and below and in particular having an internal combustion engine with the gas injector. Short description of the drawings

[0041] Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing: Fig. 1 to 4 a gas injector according to an embodiment, Fig. 5a to 9 are diagrams illustrating a mode of operation of the gas injector according to an embodiment, Fig. 10 a vehicle according to an embodiment. Embodiments of the invention

[0042] Fig. 1 shows a gas injector 10 for an internal combustion engine 100 according to one embodiment. The gas injector 10 with central gas guidance has a first valve 12 and a second valve 14, wherein the first valve 12 and the second valve 14 can at least temporarily form a detachable connection 11 with one another. Furthermore, the first valve 12 is configured to assist the second valve 14 up to a first predetermined deflection 16, wherein the second valve 14 is configured to deflect a closure element 18 from the first predetermined deflection 16 to a second predetermined deflection 20 solely within a defined working pressure range. Further preferably, the control unit 34 is configured to control the first valve 12 based on a first control profile 13. Furthermore, the control unit 34 is configured to control the second valve 14 based on a second control profile 15.

[0043] Fig. 2 shows a gas injector 10 according to one embodiment. The gas injector 10 comprises a first valve 12 and a second valve 14. A magnetic separating plate 22 is arranged between the first valve 12 and the second valve 14. More preferably, the first valve 12 comprises a coil 24 and an armature 26. In addition, the second valve 14 comprises a coil 24 and an armature 26. The coils 24 and the armatures 26 of the first valve 12 and the second valve 14 can preferably be substantially identical in construction. More preferably, the gas injector 10 comprises a nozzle spring 38, which displaces the closure element 18.

[0044] Fig. 3 shows a gas injector 10 with a first valve 12 and a second valve 14. The first valve 12 is configured to deflect the second valve 14 into a first deflection 16. More preferably, the second valve 14 can displace the closure element 18, in particular, into a second deflection 20.

[0045] Fig. 4 shows a gas injector 10 according to one embodiment. The gas injector 10 comprises a first valve 12 and a second valve 14. The first valve 12 can have a first valve stroke 28. Furthermore, the second valve 14 can have a second valve stroke 30. Further preferably, the second valve 14 is integrally connected to a nozzle needle 32 of the closure element 18. Further preferably, the gas injector 10 comprises a fluid-conducting channel 36 through which the fluid to be injected flows.

[0046] The gas injector 10 preferably comprises a control unit 34. Furthermore, the gas injector 10 can have a sensor unit 36.

[0047] Fig. Figure 5a shows a diagram with a first axis 300 representing the current and a second axis 302 representing the time course. Fig. 5a shows the first control profile 13 and the second control profile 15. The first control profile 13 and the second control profile 15 are shown in the Fig. 5a is essentially the same.

[0048] Fig. 5b shows a second diagram with a first axis 304, which represents the stroke of the closure element 18 over time 302. The profile of the stroke 312 can be specifically adjusted using the first control profile 13 and the second control profile 15. The profile of the stroke 312 shows the first joint deflection 16 of the two valves as well as the second sole deflection 20 of the second valve. Furthermore, the profile of the sole stroke profile 312 of the second valve includes a joint stroke profile 314 of the two valves during reset.

[0049] Fig. 5c shows a possible velocity profile of the nozzle needle 32. The velocity profile shown in the Fig. The diagram shown in Figure 5c shows a first axis 306, which represents the speed of the nozzle needle 32 over time 302. In the course 316 of the speed of the nozzle needle 32, the first deflection 16 and the second deflection 20 are plotted.

[0050] Fig. Figure 6a shows a diagram with a first axis 300 representing the current and a second axis 302 representing the time course. As in the Fig. As can be seen in Figure 6a, the first control profile 13 differs from the second control profile 15. Preferably, the current of the first control profile 13 can be reduced for a period 322 when the connection 11 between the two valves 12, 14 is not present. Preferably, in the period 318, the second valve 14 is in the second deflection 20.

[0051] Fig. Figure 6b shows a stroke 304 over time 302. The first deflection 16, separation of the two valves, and the second deflection 20 of the second valve are shown. The profile of the stroke 324 of the second valve differs from the profile of the stroke of the first valve 326.

[0052] Fig. 6c shows the nozzle needle speed 306 over time 302. In the course of the nozzle needle speed 328 of the second valve, the first deflection 16 as well as the second deflection 20 are shown.

[0053] Fig. 7a shows the current 300 over time 302. As in the Fig. As shown in Figure 7a, the first control profile 13 differs from the second control profile 15. The needle movement can be slowed down by means of the different control profile curves 13, 15.

[0054] Fig. 7b shows the valve lift 304 over time 302. In the Fig. Figure 7b shows the first deflection 16 as well as the second deflection 20. The course of the valve lift 338 between a first actuation and the course 340 of the valve lift in a second actuation hardly differ.

[0055] Fig. Figure 8a shows a diagram with a first axis 300 representing current and a second axis 302 representing time. Fig. 8a, the first control profile 13 differs from the second control profile 15. Different effects can be exploited by varying the starting times of changes in the control profiles 13, 15 as well as by changing the gradient of the changes in the control profiles 13, 15. Thus, a characteristic map can be shaped over the boost current duration and, in particular, purging can be performed, a late post-injection can be performed, and / or partial load operation can be realized.

[0056] Fig. 8b shows a stroke 304 over time 302. In the Fig. 8b, are due to the changed tax profiles 13, 15 as they relate to the Fig. 8a, different stroke profiles 352 are shown. By specifically modifying the control profiles 13, 15, the stroke profile, particularly the gradient, can be adjusted both during the opening of the gas injector 10 and during the closing 350.

[0057] Fig. 9 shows a magnetic force 356 versus the current strength 378. A curve 362 with an air gap of 720 µm is shown. Furthermore, a curve 346 with an air gap of 620 µm is shown. Furthermore, a curve 366 with an air gap of 520 µm is shown. Furthermore, a curve 368 with an air gap of 420 µm is shown. In addition, a curve 370 with an air gap of 320 µm is shown. Furthermore, a curve 372 with an air gap of 220 µm is shown. In addition, a curve 374 with an air gap of 120 µm is shown. Furthermore, a curve 376 with an air gap of 20 µm is shown.

[0058] Fig. 10 shows a vehicle 200 having a gas injector 10 as described above and below. Furthermore, the vehicle 200 includes an internal combustion engine 100, in particular having a gas injector 10.

Claims

[1] Gas injector (10) for an internal combustion engine (100), comprising: - a first valve (12) and a second valve (14), wherein the first valve (12) and the second valve (14) at least temporarily form a detachable connection (11) with each other, - a control unit (34), wherein the control unit (34) is configured to control the first valve (12) based on a first control profile (13), - wherein the control unit (34) is configured to control the second valve (14) based on a second control profile (15). [2] Gas injector (10) according to claim 1, wherein the first control profile (13) differs at least temporarily from the second control profile (15). [3] Gas injector (10) according to one of the preceding claims, wherein the control unit (34) is configured to keep the first control profile (13) and / or the second control profile (15) substantially constant for a first predetermined period of time in order to influence the speed profile of the nozzle needle (32) of the gas injector (10). [4] Gas injector (10) according to one of the preceding claims, wherein the control unit (34) is configured to adapt a closing speed of the gas injector (10) by means of an adaptation of the first control profile (13) and / or the second control profile (15). [5] Gas injector (10) according to claim 4, wherein the control unit (34) is configured to reduce a voltage at the first valve (12) and / or second valve (14) to substantially zero in order to reduce the closing speed of the gas injector (10). [6] Gas injector (10) according to one of the preceding claims, wherein the first control profile (13) and the second control profile (13) differ at least for a second predetermined period of time. [7] Gas injector (10) according to claim 6, wherein the control unit (34) is configured to reduce a current at the first valve (12) by means of an adaptation of the first control profile (13) for the second predetermined period of time. [8] Gas injector (10) according to one of claims 6 to 7, wherein the control unit (34) is configured to reduce a current at the second valve (14) by adjusting the second control profile (15) and / or to set it substantially to zero when the first valve (12) and the second valve (14) form a connection when the gas injector (10) is closed. [9] Gas injector (10) according to one of claims 6 to 8, wherein the control unit (34) is configured to adjust a current applied to the second valve (14) by means of the second control profile (15) in order to adjust a valve lift of the second valve (14). [10] Gas injector (10) according to claim 9, wherein the control unit (34) is configured to adjust the valve lift at the second valve (14), to adjust a starting point and / or a first increase of the drop in current at the second valve (14). [11] Gas injector (10) according to one of the preceding claims, wherein the gas injector (10) has a sensor unit (42) for monitoring a current and / or a voltage at the first valve (12) and / or at the second valve (14), wherein the control unit (34) is configured to adapt the first control profile (13) and / or the second control profile (15) by means of the sensor unit (42). [12] Gas injector (10) according to one of the preceding claims, wherein a magnetic separating plate (22) is arranged between the first valve (12) and the second valve (14). [13] Gas injector (10) according to one of the preceding claims, wherein the first valve (12) has a first valve stroke (28), wherein the second valve (14) has a second valve stroke (30), wherein the second valve stroke (30) is substantially greater than the first valve stroke (28). [14] Gas injector (10) according to one of the preceding claims, wherein the gas injector (10) has a fluid-conducting channel (36) which is spaced apart from the first valve (12) and the second valve (14) in a substantially fluid-separating manner. [15] Vehicle (200) comprising a gas injector (10) according to one of the preceding claims and in particular an internal combustion engine (100) with the gas injector (10).

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