AU2013234433B2 - Submarine - Google Patents

Abstract

A submarine has at least one internal combustion engine hooked up to an exhaust gas line. The exhaust gas line is coupled with a Helmholtz resonator, whose resonance frequency is controlled as a function of the exhaust gas temperature. \ /j

Description

2013234433 21 Aug 2017 1

DESCRIPTION

[0001] The present disclosure relates to a submarine.

[0002] One of the basic tasks during the conception of military submarines is to eliminate onboard noise sources, or at least to reduce noise generation as much as possible. In these diesel-electric powered submarines, the exhaust noise that arises with the diesel engine in operation must be decreased. Absorption mufflers built into the exhaust line have been used for this purpose to date. While the exhaust noise is muffled in a wide frequency range with these absorption mufflers, it has been shown that the ignition frequencies of internal combustion engines located in the submarine are still clearly discernible in the outside environment of the submarine despite the absorption mufflers.

[0003] It is against this background and the problems and difficulties associated therewith that the present invention has been developed.

[0004] Certain objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

[0005] According to a first aspect, there is provided a submarine comprising at least one internal combustion engine and an exhaust gas line hooked up thereto, wherein the exhaust gas line is coupled with a Helmholtz resonator comprising a length adjustable resonator neck of telescopic design, wherein a first section of the resonator neck comprises an annular chamber having a volume which can be varied in a telescoping direction of the resonator neck, wherein the annular chamber is filled with a fluid that is heat-expansible, in order to control the resonance frequency of the Helmholtz resonator by way of the length-adjustable resonator neck adjusting as a function of the exhaust gas temperature.

[0006] According to a further aspect, there is provided a submarine comprising at least one internal combustion engine and an exhaust gas line hooked up thereto, whereby the exhaust gas line is coupled with a Helmholtz resonator comprising a length-adjustable resonator neck, and a bimetal spring element which is movably coupled with a telescoping section of the resonator neck and joined with the exhaust gas line in a thermally conductive manner, in order to control the resonance frequency of the Helmholtz resonator by way of the length-adjustable resonator neck adjusting as a function of the exhaust gas temperature. 2 2013234433 21 Aug 2017 [0007] The internal combustion engine can generally involve any internal combustion engine accommodated in a submarine. However, this internal combustion engine is preferably a diesel engine, which is placed upstream from a generator used to charge a battery system.

[0008] In one form, the exhaust line is coupled with a Helmholtz resonator. Helmholtz resonators usually exhibit a resonator neck adjoined by a resonator pot, whose inner cross section is larger than that of the resonator neck. In addition to the Helmholtz resonator, the exhaust line can incorporate one or more absorption mufflers.

[0009] Helmholtz resonators are especially suited for reducing the level of a specific frequency. In the submarine according to the invention, the Helmholtz resonator coupled to the exterior side of the exhaust line is intended to reduce the exhaust noise generated by the ignition frequency of the internal combustion engine. However, the frequency of this exhaust noise changes as a function of temperature during the startup phase of the engine, and as a function of the tapped power of the internal combustion engine. In order to take this circumstance into account, the invention provides that the resonance frequency of the Helmholtz resonator is controlled as a function of the exhaust gas temperature.

[0010] The invention provides that the resonance frequency of the Helmholtz resonator is controlled by adjusting the volume of the resonator neck and/or resonator pot as a function of the exhaust gas temperature to the exhaust noise frequency that varies with the exhaust gas temperature. This measure ensures that the Helmholtz resonator optimally diminishes or at best eliminates the exhaust noise, even in the case of temperature-induced frequency changes, for example while starting up the internal combustion engine or changing the tapped power of the internal combustion engine.

[0011] In order to control the resonance frequency of the Helmholtz resonator used according to the invention, the length of the resonator pot, its cross section, as well as the length or cross section of the resonator neck can be variable in design. Structural configurations of Helmholtz resonators that allow this are sufficiently known from prior art. It is structurally especially simple to vary the length of the resonator neck for controlling the resonance frequency of the Helmholtz resonator. Preferred according to the invention in this respect is a configuration in which the resonator neck of the Helmholtz resonator exhibits an adjustable length. The length of the resonator neck is here controlled in such a way as to increase given a rise in the exhaust gas temperature, and to decrease given a drop in the exhaust gas temperature.

[0012] This adjustable length of the resonator neck is advantageously achieved by giving the resonator neck a telescoping design. As a result, the resonator neck exhibits at least two intertwining sections, which can be moved to a certain extent relative to each other, thereby changing the length of the resonator neck while keeping the cross section of the resonator neck virtually the same. Other 3 2013234433 21 Aug 2017 structural solutions that permit an adjustable length of the resonator neck are also conceivable in addition to the telescoping configuration of the resonator neck. For example, this adjustable length of the resonator neck can also be achieved in a configuration of the outer wall of the resonator where two sections of the resonator neck are joined together by a threaded connection.

[0013] A telescoping embodiment of the resonator neck preferably provides that a section of the resonator neck is formed by an annular chamber, whose volume can be varied in the telescoping direction, i.e., in the longitudinal direction of the resonator neck. In this case, the annular chamber is best bordered in the telescoping direction of the resonator neck by a wall, which can be displaced within certain limits in the telescoping direction of the resonator neck given a change in the volume of the annular chamber. This wall can accommodate a second section of the resonator neck, or this wall can be formed by a second section of the resonator neck that engages into the annular chamber.

[0014] Advantageously provided in this conjunction is an embodiment in which the resonator neck exhibits a hollow cylindrical, dual-walled section. A gap between an inner wall and outer wall here forms the annular chamber, into which engages an annular piston comprising the second section of the resonator neck. The annular chamber formed between the inner and outer wall of the dual-walled section of the resonator neck can advantageously be used for accommodating means with which its displaceable wall or the second section of the resonator neck can be moved as a function of the exhaust gas temperature.

[0015] The annular chamber is preferably filled with a fluid. The goal of this step is to use a volumetric expansion of the fluid that occurs while heating the fluid to enlarge the volume of the annular chamber, and as a consequence thereof, the length of the resonator neck. Basically any type of fluid can be filled into the annular chamber, wherein the most suitable fluid must typically be selected as a function of the structural configuration of the Helmholtz resonator and required change in length of the resonator neck.

[0016] It is best that the temperature of the fluid present in the annular chamber changes as a direct function of the exhaust gas temperature. In order to ensure that this happens, the annular chamber is preferably connected in a heat-conducting manner with the exhaust gas line. In other words, the annular chamber is situated in such a way that heat can flow from the exhaust gas to the fluid in the annular chamber.

[0017] As provided in another advantageous embodiment, this flow of heat from the exhaust gas to the fluid can be made especially simple by having the annular chamber be a section of the resonator neck that directly adjoins the exhaust gas line, so that the heat of the exhaust gas can be transmitted to the fluid in the annular chamber directly via the outer wall of the exhaust gas line and an inner wall of the annular chamber. 4 2013234433 21 Aug 2017 [0018] As an alternative to a fluid situated in an annular chamber with a variable volume, a telescoping configuration of the resonator neck in which two resonator neck sections are joined together by a threaded connection can advantageously also provide a bimetal spring element, which is moveably coupled with a section of the resonator neck in such a way that this resonator neck section becomes twisted by a temperature-induced deformation of the bimetal spring element relative to the other section of the resonator neck, thereby changing the length of the resonator neck. The bimetal spring element can here be movably coupled directly with the corresponding section of the resonator neck, i.e., the bimetal spring element can be directly joined with this section of the resonator neck, or the bimetal spring element can be movably coupled indirectly with this section of the resonator neck, wherein a mechanical system is arranged between the bimetal spring element and telescoping section of the resonator neck for transmitting the movement.

[0019] When using a bimetal spring element, the latter is best joined with the exhaust gas line in a thermally conductive manner. The bimetal spring element is preferably situated directly on the exterior side of the exhaust gas line. The bimetal spring element is here preferably arranged on the exterior side of the resonator neck, so that movement of the bimetal spring element is coupled with the telescoping section of the resonator neck on the exterior side of the resonator neck.

[0020] The invention will be explained in greater detail based on an exemplary embodiment shown on the drawing. The respective views on the drawing have been schematically greatly simplified, wherein [0021] Fig. 1 presents a schematic diagram showing a section of the submarine incorporating an internal combustion engine hooked up to an exhaust gas line, which is coupled with a Helmholtz resonator, [0022] Fig. 2 presents a magnified, perspective view showing the Helmholtz resonator depicted on Fig. 1, and [0023] Fig. 3 presents a magnified sectional view showing a resonator neck of the Helmholtz resonator depicted on Fig. 1 and 2, [0024] Fig. 4 presents a magnified sectional view showing a resonator neck of a Helmholtz resonator with threaded telescoping system, and [0025] Fig. 5 presents a sectional view along a cutting line V-V on Fig. 4. 5 2013234433 21 Aug 2017 [0026] In the section of a submarine shown on Fig. 1, an internal combustion engine 4 is mounted on a base plate 2 cushioned against vibration. The internal combustion engine 4 is a diesel engine. The base plate 2 is mounted on a deck 6 of the submarine so as to cushion it against vibration. The internal combustion engine 4 is coupled by its drive shaft 8 with a generator 10, which is set up on the base plate 2 cushioned against vibration next to the internal combustion engine 4. The generator 10 is used to charge a battery system (not shown on the drawing) of the submarine.

[0027] An exhaust gas line 12 is hooked up to the internal combustion engine 4. The exhaust gas line 12 is only partially depicted on Fig. 1, and runs (not evident from Fig. 1) through a pressure hull wall 14 toward the outside of the pressure hull of the submarine. An absorption muffler 16 is located directly at the output side of the internal combustion engine 4 in the exhaust gas line 12.

[0028] The exhaust gas line 12 is coupled with a Helmholtz resonator 18 on the output side of the absorption muffler 16. The Helmholtz resonator 18 is used in particular to diminish, and at best completely eliminate, the exhaust noise caused by the ignition frequency of the internal combustion engine 4. As may be gleaned in particular from Fig. 2, the Helmholtz resonator 18 exhibits a resonator neck 20, which is connected directly to the exhaust gas line 12. A resonator pot 22 of the Helmholtz resonator 18 adjoins the end of the resonator neck 20 averted from the exhaust gas line 12, and exhibits a design that is open toward the resonator neck 20, but otherwise closed. In order to establish a connection that allows a flow from the exhaust gas line 12 into the Helmholtz resonator 18, an opening 24 is formed in the exhaust gas line 12 (Fig. 3). Exhaust gas generated by the internal combustion engine 4 can flow through this opening 24 in the essentially tubular resonator neck 20, and from there into the hollow cylindrical resonator pot 22.

[0029] In order to be able to control the resonator frequency of the Helmholtz resonator 18 as a function of the exhaust gas temperature, its resonator neck 20 has a telescoping design. For this purpose, a section of the resonator neck 20 directly adjoining the exhaust gas line 12 is given a dual-walled configuration, comprised of an inner, tubular wall 24 and an outer, tubular wall 26 arranged concentrically thereto. An annular chamber 30 is created by a gap between the inner wall 24 that directly adjoins the exterior side of the opening 24 formed on the exhaust gas line 12 and the outer wall 26. This annular chamber 30 is sealed at one end by the exterior side of the exhaust gas line 12. The other end of the annular chamber 30 averted from the exhaust gas line 12 has an open design. This open end of the annular chamber 30 extends into it an annular piston 32, which is situated on a front end of the resonator pot 22 facing the resonator neck 20 and there envelops an opening 34 that forms a connection in terms of flow from the resonator neck 20 to the resonator pot 22. The piston 32 is guided in the annular chamber 30 so that it can move with little play in the longitudinal direction of the resonator neck, and forms a second section of the resonator neck 20. Formed around the opening 34 on the front end of the resonator pot 22 facing the resonator neck 20 is a tubular projection 36, which engages into the resonator neck with a slight, radial play. 6 2013234433 21 Aug 2017 [0030] Inside the annular chamber 30, a space bordered by the exterior side of the exhaust gas line 12 and the end of the piston 32 is completely filled with a fluid. For example, if the exhaust gas temperature rises while starting up the internal combustion engine 4, this also causes the temperature of the fluid inside the annular chamber 30 to rise. This in turn leads to a thermal expansion of the fluid in the annular chamber 30, as a result of which the piston 32 engaging into the annular chamber 30 is pushed by the fluid in the direction away from the exhaust gas line 12, thereby increasing the length of the resonator neck 20, i.e., telescoping the resonator neck 20. Conversely, a drop in the exhaust gas temperature decreases the volume of fluid in the annular chamber 30 owing to the associated drop in fluid temperature, as a result of which the piston 32 moves in the direction of the exhaust gas line 12, thereby reducing the length of the resonator neck. Given a suitable structural configuration of the Helmholtz resonator 18 and selection of a suitable fluid, this makes it possible to control the resonance frequency of the Helmholtz resonator 18 in such a way that the exhaust noise caused by the ignition frequency of the internal combustion engine 4 is at best eliminated, but at the very least diminished to a quite significant extent.

[0031] In the resonator neck 20’ depicted on Fig. 4 and 5, a pipe length 38 is welded to the exterior side of the exhaust line 12. The pipe length 38 forms a first, fixed section of the resonator neck 20’, and here envelops the opening 24 formed on the exhaust gas line 12.

[0032] A bushing 40 is arranged around the pipe length 38. The bushing 40 can be turned around a central axis A of the resonator neck 20’. A projection 42 extending radially into the interior of the bushing 40 is formed in the area of an end of the bushing 40 that adjoins the exhaust gas line 12. This projection 42 engages into a groove 44 that is formed on the outer periphery of the pipe length 38, and extends around the entire periphery of the pipe length 38. This prevents the bushing 40 from being able to move in the direction of the central axis A of the resonator neck 20. Proceeding from an end of the bushing 40 averted from the exhaust gas line 12, the bushing 40 exhibits a female thread 46. The female thread 46 ends at a relief groove 48 formed on the inner periphery of the bushing 40 adjacent to the projection 42.

[0033] A pipe length 50 is screwed to the female thread 46 of the bushing 40. To this end, the pipe length 50 exhibits a male thread 52. The pipe length 50 comprises a second section of the resonator neck 20’, on which is situated a resonator pot 22, wherein an opening 34 establishes a connection that allows a flow from the resonator neck 20’ to the resonator pot 22. Proceeding from an end of the pipe length 50 facing the exhaust gas line 12, a longitudinal groove 54 aligned parallel to the central axis A of the resonator neck 20’ is formed on the interior side of the pipe length 50. This longitudinal groove 54 has engaging into it a key 56, which is fixed on a recess 58 of the outer lateral surface of the pipe length 38. This prevents the pipe length 50 from turning around the central axis A of the resonator neck 20’. 2013234433 21 Aug 2017 7 [0034] A lever 60 extending radially outward is arranged on the outer lateral surface of the bushing 40 in an area adjoining the exhaust gas line 12. As evident from Fig. 5, the lever 60 is connected with a bimetal spring element 62 secured to the exterior side of the exhaust gas line 12. The bimetal spring element 62 is designed as a spiral spring.

[0035] A rise in temperature inside the exhaust gas line 12 heats up the bimetal spring element 62, which then expands. This exerts a force on the lever 60 that causes the pipe length 50 to become unscrewed from the female thread 46 of the bushing 40, thereby increasing the length of the resonator neck 20’, and hence its volume. Conversely, a reduction in exhaust gas temperature causes the bimetal spring element 62 to contract, so that the pipe length 50 is screwed further into the bushing 40, and the length and volume of the resonator neck 20’ diminish.

[0036] Advantageously then, it can be seen that the present disclosure provides a submarine in which the frequency levels of the ignition frequencies generated by internal combustion engines located in the submarine can be diminished to a sufficient extent.

[0037] Throughout the specification and the claims that follow, unless the context requires otherwise, the words “comprise” and “include” and variations such as “comprising” and “including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[0038] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

[0039] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims. 2013234433 21 Aug 2017

Reference List 2 Base plate 4 Internal combustion engine 6 Deck 8 Drive shaft 10 Generator 12 Exhaust gas line 14 Pressure hull wall 16 Absorption muffler 18 Helmholtz resonator 20,20’ Resonator neck 22 Resonator pot 24 Opening 26 Wall 28 Wall 30 Annular chamber 32 Piston 34 Opening 36 Projection 38 Pipe length 40 Bushing 42 Projection 44 Groove 46 Female thread 48 Relief groove 50 Pipe length 52 Male thread 54 Longitudinal groove 56 Key 58 Recess 60 Lever 62 Bimetal spring element A Central axis

Claims (7)

1. A submarine comprising at least one internal combustion engine and an exhaust gas line hooked up thereto, wherein the exhaust gas line is coupled with a Helmholtz resonator comprising a length adjustable resonator neck of telescopic design, wherein a first section of the resonator neck comprises an annular chamber having a volume which can be varied in a telescoping direction of the resonator neck, wherein the annular chamber is filled with a fluid that is heat-expansible, in order to control the resonance frequency of the Helmholtz resonator by way of the length-adjustable resonator neck adjusting as a function of the exhaust gas temperature.

2. The submarine according to claim 1, wherein the resonator neck comprises a hollow cylindrical, dual-walled section, wherein a gap between an inner wall and an outer wall forms the annular chamber, into which there engages an annular piston comprising a second section of the resonator neck.

3. The submarine according to either of claims 1 or 2, wherein the annular chamber is joined with the exhaust gas line in a thermally conductive manner.

4. The submarine according to any one of claims 1-3, wherein the annular chamber is a section of the resonator neck that directly adjoins the exhaust gas line.

5. The submarine according to any one of claims 1-4, further comprising a bimetal spring element which is movably coupled with a telescoping section of the resonator neck.

6. The submarine according to claim 5, wherein the bimetal spring element is joined with the exhaust gas line in a thermally conductive manner.

7. A submarine comprising at least one internal combustion engine and an exhaust gas line hooked up thereto, whereby the exhaust gas line is coupled with a Helmholtz resonator comprising a length-adjustable resonator neck, and a bimetal spring element which is movably coupled with a telescoping section of the resonator neck and joined with the exhaust gas line in a thermally conductive manner, in order to control the resonance frequency of the Helmholtz resonator by way of the length-adjustable resonator neck adjusting as a function of the exhaust gas temperature.