EMISSION SIGNATURE MODIFICATION DEVICE

Abstract

An emission signature modification device for modifying an acoustic signature of an exhaust gas stream, including an exhaust gas guiding device that guides the exhaust gas stream in the flow direction thereof from an inlet area to an outlet area. An active acoustic emission modification device modifies the acoustic emission of the exhaust gas stream in predetermined operating states. If an actuator system of the active acoustic emission modification device is designed such that in a circumferential direction, the actuator system is surrounded by more than 30% of the guided exhaust gas stream, the actuating system can be protected against harmful influences from the environment by way of the exhaust gas guiding device on the one hand, and on the other hand, the required space signifier can be reduced as compared to a lateral, external arrangement of the actuating system.

Claims

1-15. (canceled)

16. An emission signature modification device for modification of an acoustic signature of an exhaust gas stream, comprising: an exhaust gas guiding device that guides the exhaust gas stream a flow direction from an inlet region to an outlet region; and an active acoustic emission modification device, that modifies an acoustic emission of the exhaust gas stream in predetermined operating states, wherein the active acoustic emission modification device includes an actuator system, wherein more than 30% of the actuator system is surrounded in a circumferential direction by the guided exhaust gas stream.

17. The emission signature modification device according to claim 16, wherein the exhaust gas guiding device has an outer shell, wherein the exhaust gas stream is passed at least partially through the outer shell.

18. The emission signature modification device according to claim 17, wherein the exhaust gas guiding device includes an inner shell, wherein the exhaust gas stream is guided at least partially between the outer shell and the inner shell of the exhaust gas guiding device.

19. The emission signature modification device according to claim 18, wherein at least one of the shells is constructed for fluid flow at least in sections.

20. The emission signature modification device according to claim 18, wherein the inner shell has an extent that amounts to at least 1% of an extent of the outer shell in the flow direction.

21. The emission signature modification device according to claim 17, further comprising at least one component arranged within the outer shell to guide the exhaust gas stream, wherein there is a flow of fluid through the component.

22. The emission signature modification device according to claim 16, wherein the outlet region has a cross-sectional area perpendicular to the flow direction that is 90% smaller than a central cross-sectional area of the emission signature modification device perpendicular to the flow direction.

23. The emission signature modification device according to claim 16, wherein the emission signature modification device is designed for modification of a heat signature of an exhaust gas stream.

24. The emission signature modification device according to claim 17, further comprising a heat emission modification device that modifies heat emission of the exhaust gas stream in predetermined operating states.

25. The emission signature modification device according to claim 24, wherein the heat emission modification device comprises a first cooling device having a first cooling fluid.

26. The emission signature modification device according to claim 25, wherein the first cooling device is formed at least partially by the outer shell through which there is a fluid flow.

27. The emission signature modification device according to claim 25, further comprising a second cooling device having a second cooling fluid by which the actuator system is cooled.

28. The emission signature modification device according to claim 27, wherein the first cooling device is fluidically connected to the second cooling device.

29. The emission signature modification device according to claim 16, wherein the active acoustic emission modification device includes an acoustic diaphragm driven by the actuator system, wherein the acoustic diaphragm is water-resistant.

30. The emission signature modification device according to claim 29, wherein the acoustic diaphragm is seawater-resistant,

31. The emission signature modification device according to claim 16, wherein the emission signature modification device is a separate subassembly, which, in the flow direction, is positionable centrally or at an end in an exhaust section.

Description

[0037] Of the figures, each of which is schematic:

[0038] FIG. 1 shows an emission signature modification device having an internal actuator system and a second cooling device, which cools the actuator system,

[0039] FIG. 2 shows an emission signature modification device having an outer shell, through which fluid flows, and an inner shell, through which fluid flows.

[0040] As shown in FIG. 1, the emission signature modification device 100 has an exhaust gas guiding device 110, which guides an exhaust gas stream 120 at least in one segment or segments between an outer shell 130 and an inner shell 140.

[0041] Here, an extent 150 of the outer shell 130 is made larger than an extent 160 of the inner shell 140. Accordingly, a region 180 which is free from the inner shell 140 is formed in an outlet region 170 of the emission signature modification device 100. In this region 180, soundwaves 190 produced by the movement of an actuator system 200 of an active acoustic emission modification device 210 can enter into interaction directly with the acoustic emission 220 of the exhaust gas stream 120, thus allowing a desired modification of the acoustic signature to be established. By virtue of the design, the actuator system 200 is surrounded in a circumferential direction 230 at least segmentally by an exhaust gas stream 120. By virtue of this arrangement of the actuator system 200, which is central in relation to the flow direction 240, the required installation space for the active acoustic emission modification device 210 is reduced, on the one hand, and the active acoustic emission modification device 210 is protected by the exhaust gas guiding device 110 from the external effects due to the environment, on the other hand. Here, the flow direction 240 extends from an inlet region 250 (not shown in FIGS. 1 and 2) to the outlet region 170.

[0042] In the embodiment according to FIG. 1, the outer shell 130 is designed for a fluid throughflow, while the inner shell 140 is formed merely by a tubular plate or the like, for example. Thus, the outer shell 130 forms a first cooling device 260. By means of this first cooling device 260, the heat signature of the exhaust gas stream 120 can be modified in a desired manner by means of at least one first cooling fluid 265, which circulates in the outer shell 130, through which the fluid flows. In this arrangement, the inner shell 140 is designed merely as a tubular plate, thus allowing the exhaust gas stream to be guided by both shells 130, 140 in the gap between the outer shell 130 and the inner shell 140.

[0043] Moreover, a second cooling device 270 of a heat emission modification device 275 is provided, by means of which the actuator system 200 can be cooled. This second cooling device 270 is designed as a branch 280 from the first cooling device 260, wherein the fluid flowing through the outer shell 130 is guided to the actuator by means of the branch 280, with the result that the actuator system 200 is cooled by the first cooling fluid 265 of the first cooling device 260 and by means of the second cooling device 270. Accordingly, the first cooling device 260 is fluidically connected to the second cooling device 270. However, it is also conceivable for the second cooling device 270 to contain a separate second cooling fluid 285, while the first cooling device 260 is operated with a different first cooling fluid 265 as a working medium.

[0044] A cross-sectional area 290 of the outlet region 170 perpendicular and transverse to the flow direction 240 is made smaller than a central cross-sectional area 300 perpendicular to the flow direction 240. Accordingly, the exhaust gas stream 120 guided along the boundary or adjacent to the shell is brought back together again in the outlet region 170 in such a way that disadvantages relating to flow and those of other kinds are avoided.

[0045] An acoustic diaphragm 310 of the active acoustic emission modification device 210 is driven by the actuator system 200 in such a way that the soundwaves 190 can be radiated in a desired manner.

[0046] In the embodiment in FIG. 2, the cooling of the actuator system 200 is ensured by means of an inner shell 140, through which there is an additional fluid flow. In this case, the first cooling device 260 can be designed to be fluidically independent of the second cooling device 270 and can have an additional second cooling fluid 285, or fluidic coupling of the two cooling devices 260, 270 is ensured by means of appropriate connections. By virtue of the structural arrangement, the second cooling device 270 serves, on the one hand, to cool the exhaust gas stream 120 and also to reduce the thermal stress imposed on the actuator system 200 by the exhaust gas stream 120 since the second cooling device 270 is arranged between the exhaust gas stream 120 and the actuator system 200.