Exhaust silencer system, armored multi-purpose vehicle, and method

Abstract

The invention relates to an exhaust silencer system (6) for an armored multi-purpose vehicle (1), comprising: an exhaust silencer (7); a cooling-air guide housing (21) attached to the exhaust silencer (7); and an electrothermal converter device (30) attached to the outside of the exhaust silencer (7) and the inside of the cooling-air guide housing (21) for actively withdrawing heat (W) from the exhaust silencer (7) which the converter device (30) supplies to cooling air (L) flowing through the cooling-air guide housing (21) in order to influence a heat signature (S) of the exhaust silencer system (6).

Description

[0001] The present invention relates to an exhaust silencer system for a protected vehicle, a protected vehicle with such an exhaust silencer system and a method for operating such an exhaust silencer system.

[0002] In military vehicles, great importance is placed on signature reduction in all aspects. One problem that can arise in this regard is the removal of hot exhaust gases from an internal combustion engine. Due to the generally short and direct exhaust paths, a so-called hotspot can occur at the point of exhaust gas exiting the vehicle, which is only slightly colder than the outlet temperature of the exhaust gas from the internal combustion engine itself. Furthermore, the exhaust path also heats surrounding components of the vehicle, including the vehicle's exterior.

[0003] This heating creates a pattern characteristic of each vehicle type, specifically a distinctive heat signature, which enemy reconnaissance aircraft can use to precisely identify the vehicle type. In a hybrid powertrain, the combustion engine is not running throughout the entire operation of the vehicle, but rather undergoes a start-stop cycle as needed. This creates the problem of repeatedly accumulating heat in an exhaust pipe, which then heats up disproportionately, thus exacerbating the hotspot problem.

[0004] According to internal findings, attempts are made to artificially lengthen the exhaust tract in military vehicles and surround it with a shell of heat-insulating material. The longer exhaust tract releases more heat into the environment, which lowers the exhaust temperature at the exhaust outlet. It is also possible to mix the exhaust gas with a cooling air stream or an additional air stream from the vehicle before the exhaust outlet.

[0005] However, the aforementioned solutions require a lot of space and are heavy. The problem of the characteristic heat signature is only inadequately addressed. Especially after the combustion engine is switched off and cooled down, the escaping heat spreads uncontrollably and heats up the entire vehicle. This needs to be improved.

[0006] DE 10 2015 205 318 A1 shows a silencer for an exhaust system of a vehicle, with a silencer housing which has an exhaust gas inlet pipe through which exhaust gas flows into the silencer housing, and an exhaust gas outlet pipe through which exhaust gas flows out of the silencer housing, wherein at least part of the silencer housing or the entire silencer housing is surrounded by a jacket housing, and wherein an air gap is provided between the silencer housing and the jacket housing.

[0007] DE 10 2005 005 078 A1 describes a thermoelectric generator for use with an internal combustion engine connected to an exhaust duct, wherein the generator includes a catalyst device arranged in the exhaust duct for the purpose of purifying the exhaust gas, wherein the generator has a thermoelectric generator element arranged on the catalyst device for converting thermal energy of the exhaust gas flowing through the exhaust duct into electrical energy, wherein the thermoelectric generator element is arranged on at least one downstream portion of the catalyst device with respect to the flow of the exhaust gas.

[0008] Against this background, it is an object of the present invention to provide an improved silencer system for a protected vehicle.

[0009] Accordingly, an exhaust silencer system for a protected vehicle is proposed. The exhaust silencer system comprises an exhaust silencer, a cooling air guide housing attached to the exhaust silencer, and an electrothermal converter device mounted externally on the exhaust silencer and within the cooling air guide housing for actively extracting heat from the exhaust silencer. The converter device transfers heat to cooling air flowing through the cooling air guide housing to influence a heat signature of the exhaust silencer system.

[0010] Because the converter device can influence or alter the heat signature of the exhaust silencer system, it is no longer possible to clearly identify the vehicle type of a vehicle equipped with such an exhaust silencer system. The exhaust silencer system thus contributes to the survivability of the vehicle and its crew members. The exhaust silencer system can actively prevent thermal hotspots on the vehicle from revealing both the position and the identity of the vehicle.

[0011] The exhaust silencer system can, in particular, be a rear silencer. The exhaust silencer system can, for example, be arranged in a rear area, a front area, or a side area of ​​the vehicle. The exhaust silencer is, in particular, a resonance exhaust silencer. However, the exhaust silencer can also be an absorption exhaust silencer. The exhaust silencer is preferably cuboid-shaped or cylindrical and comprises an exhaust gas supply pipe for supplying exhaust gas from an internal combustion engine to the exhaust silencer and an exhaust gas discharge pipe for discharging the exhaust gas from the exhaust silencer.

[0012] The exhaust silencer encloses a volume that is preferably divided into several chambers. For example, the exhaust gas supply pipe opens into one of the chambers, and the exhaust gas discharge pipe opens into another. The exhaust gas thus flows from the exhaust gas supply pipe through the chamber to the exhaust gas discharge pipe, with the sound being reflected in the chambers. This achieves a reduction in noise.

[0013] The exhaust silencer may comprise a cover facing away from a surface on which the vehicle travels, a base facing the surface, two facing side walls, a front wall, and a rear wall. The exhaust silencer may be made of sheet steel, in particular stainless steel.

[0014] The cooling air guide housing encloses or covers the exhaust silencer, at least in sections. For example, the cooling air guide housing covers one of the side walls and the base of the exhaust silencer. However, the cooling air guide housing can also completely enclose or cover the exhaust silencer. A cooling air duct, in which the converter device is located, is formed between the exhaust silencer and the cooling air guide housing. The cooling air flows through the cooling air duct. The cooling air guide housing is, in particular, firmly connected to the exhaust silencer. For example, the cooling air guide housing is riveted, screwed, or welded to the exhaust silencer.

[0015] The fact that the converter device is mounted "outside" on the exhaust silencer means in this case that the converter device is not located in the volume enclosed by the exhaust silencer, but rather outside the volume, for example, on one of the side walls and / or the bottom of the exhaust silencer. "Inside" the cooling air guide housing means in this case, in particular, that the converter device is placed in the aforementioned cooling air duct. This means that the cooling air guide housing covers the converter device. The exhaust silencer system can comprise multiple converter devices. For example, a separate converter device is located on the bottom and on one of the side walls.

[0016] An "electrothermal converter device" is understood here to mean a component or device designed to transport heat or convert heat into electrical energy by supplying electrical energy. An example of such a converter device is a so-called Peltier element. A control and / or regulating device is preferably provided to control the converter device.

[0017] The fact that the converter device "actively" extracts heat from the exhaust silencer means, in this case, that energy, particularly electrical energy, is supplied to the converter device so that the converter device extracts the heat from the exhaust silencer. The exhaust silencer itself is heated by the exhaust gas. Thus, the converter device extracts heat from the exhaust gas indirectly via the exhaust silencer.

[0018] In this case, the "heat signature" of the exhaust silencer system can be understood as the thermal radiation, particularly infrared radiation, emitted by the exhaust silencer system, which can be detected in particular by a photoreceiver of a thermal imaging device and displayed, for example, on a screen. The heat signature arises in particular from the exhaust silencer system emitting heat, particularly in the form of infrared radiation. Furthermore, the heat signature also results from the heating of vehicle components surrounding the exhaust silencer system, which also emit heat.

[0019] As previously mentioned, the heat signature can be characteristic of a specific vehicle type. This characteristic results from a two-dimensional geometry, in particular an outline, the heat signature, and a pattern of the heat signature. A "pattern" is understood here to mean that the heat signature has areas with high heat radiation and areas with heat radiation that is smaller than that of the former. The heat signature can comprise any number of different areas with different heat fluxes or different radiation intensities.

[0020] By "influencing" or "changing" the heat signature, we mean, in particular, that the emitted heat radiation is reduced, for example, or that it is no longer emitted in certain characteristic areas of the vehicle. For example, the two-dimensional geometry and / or the pattern of the heat signature can be influenced. In particular, by influencing or changing the heat signature, a thermal signature reduction or signature control can be achieved.

[0021] The cooling air can be forced through the cooling air duct housing, for example, by the wind generated when the vehicle is moving. Alternatively, a ventilation device can be provided that forces the cooling air through the cooling air duct housing. This has the advantage that the cooling air continues to flow through the cooling air duct housing even when the vehicle and / or the combustion engine are stationary. The ventilation device can also be controlled by the control and / or regulating device.

[0022] According to one embodiment, the converter device can be switched from a first operating state, in which the converter device releases the heat to the cooling air flowing through the cooling air guide housing, into a second operating state in that the converter device interrupts a heat flow from a hot side of the converter device facing the exhaust silencer to a cold side of the converter device facing away from the exhaust silencer.

[0023] To switch the converter device, the exhaust silencer system comprises the aforementioned control and / or regulating device. The control and / or regulating device is suitable, for example, for supplying current to the converter device. The control and / or regulating device can comprise a computer unit. Preferably, the converter device comprises a plurality of converter elements, each converter element having a hot side and a cold side. The hot side can also be referred to as the hot side of the converter device, and the cold side can also be referred to as the cold side of the converter device. In particular, to switch the converter device from the first operating state to the second operating state, a voltage applied to the converter device in the first operating state is reversed, so that the converter device no longer conducts the heat away from the exhaust silencer, but rather interrupts the heat flow.In particular, the converter device can supply heat to the exhaust silencer in the second operating state. This means, in particular, that in the second operating state, the converter device can absorb heat from the cooling air and transfer it to the exhaust silencer. In the second operating state, the exhaust silencer is thus prevented from dissipating heat. The heat is, in particular, actively retained in the exhaust silencer with the aid of the converter device. This is particularly advantageous if the vehicle is a hybrid vehicle and the combustion engine is not running continuously.

[0024] According to a further embodiment, the converter device can be switched from the first operating state or from the second operating state into a third operating state in which the converter device converts thermal energy into electrical energy with the aid of a temperature difference between the hot side of the converter device and the cold side of the converter device.

[0025] This switching can also be carried out with the aid of the control and / or regulating device. In particular, the converter device also extracts heat from the exhaust silencer in the third operating state. However, less heat is extracted in the third operating state than in the first operating state. In particular, no additional electrical energy is used in the third operating state to extract the heat. The electrical energy generated in the third operating state can be fed into an energy storage device, in particular into an accumulator, in the vehicle. The conversion of thermal energy into electrical energy occurs with the aid of the so-called Seebeck effect. This means that part of the energy converted into heat can be recovered. In the event that the vehicle is a hybrid vehicle, this effect can be used in particular to extend purely electric operation.This can, for example, extend the duration of a vehicle’s use.

[0026] According to a further embodiment, the converter device comprises a plurality of electrothermal converter elements that can be individually controlled in order to generate a predetermined pattern in the heat signature of the exhaust silencer system.

[0027] The converter elements are preferably Peltier elements. The converter elements can, for example, each have dimensions of 20 to 90 mm x 20 to 90 mm and a thickness of 3 to 5 mm. The fact that the converter elements are "individually" controllable means in this case that each converter element can be controlled, for example, energized, independently of all other converter elements. For example, any converter element can be switched to any operating state using the control and / or regulating device. The predetermined pattern can, for example, be a heat signature of another vehicle whose heat signature is to be simulated. The converter elements of the converter device are preferably arranged in a grid, pattern, or checkerboard pattern. This means that the converter elements are placed in rows and columns. The totality of all converter elements together forms the converter device.

[0028] According to a further embodiment, the converter elements can be controlled in such a way that the heat signature of the exhaust silencer system adapts to a heat signature of an environment of the exhaust silencer system.

[0029] In particular, the heat signature of the exhaust silencer system can adapt to the vehicle's surroundings and / or to a surface on which the vehicle is moving. For example, the heat signature of the exhaust silencer system can adapt to a building or another vehicle in front of which the vehicle with the exhaust silencer system is parked. This enables the vehicle to be effectively camouflaged. The exhaust silencer system can comprise a sensor system that can detect the heat signature of the surroundings and / or the surface. The sensor system can comprise an infrared sensor, for example. The sensor system can provide sensor signals to the control and / or regulating device. The control and / or regulating device can then control the transducer device or the individual transducer elements based on the sensor signals such that the heat signature of the exhaust silencer system adapts to the heat signature of the surroundings and / or the surface.

[0030] According to a further embodiment, the converter device comprises a heat sink which projects into a cooling air duct provided between the exhaust silencer and the cooling air guide housing.

[0031] The converter elements preferably have a common heat sink. However, each converter element can also have its own heat sink. The heat sink is thermally conductively connected to the converter elements, in particular with the aid of a layer of a material with high thermal conductivity, in particular a layer of thermally conductive paste. The converter elements, in turn, are connected with their hot side to the exhaust silencer with the aid of a further layer of the material with high thermal conductivity, in particular a further layer of thermally conductive paste. The heat sink is preferably made of aluminum. The heat sink comprises cooling fins through which the cooling air flows. The cooling fins are arranged such that the cooling air flows through them parallel to the cooling fins. The cooling fins extend from a plate-shaped base section of the heat sink. The base section is thermally conductively connected to the converter elements.

[0032] According to a further embodiment, the converter device is mounted on a bottom and on a side wall of the exhaust silencer.

[0033] For example, the transducer elements arranged on the floor and the transducer elements arranged on the side wall can each comprise their own heat sink. However, the transducer device can also be mounted on the ceiling, the second side wall, the front, and / or the rear of the exhaust silencer. Preferably, the transducer device is mounted on those areas of the exhaust silencer that face outward toward the vehicle's surroundings.

[0034] According to a further embodiment, the exhaust silencer comprises an exhaust outlet, wherein the cooling air guide housing comprises a cooling air outlet, and wherein the cooling air outlet is guided at least partially around the exhaust outlet.

[0035] For example, the exhaust outlet is circular. The cooling air outlet can be curved in an arc or kidney shape. The cooling air exiting the cooling air outlet, which is colder than the cooled exhaust gas, thus forms a curtain or sheath flow around the escaping cooled exhaust gas.

[0036] This further reduces the signature at the exhaust outlet. The cooling air and exhaust gas only mix at a certain distance downstream of the exhaust outlet, preventing the formation of a hot spot.

[0037] According to a further embodiment, the cooling air guide housing comprises a cooling air distributor for uniformly distributing the cooling air to the converter device, wherein the cooling air can be supplied to the cooling air distributor by means of a cooling air inlet of the cooling air guide housing.

[0038] The cooling air guide housing also includes a cooling air collector, which supplies the cooling air to the cooling air outlet after it has flowed around the heat sink(s). The cooling air can be supplied to the cooling air inlet, for example, using the aforementioned ventilation device. The control and / or regulating device can also be suitable for controlling the ventilation device, so that it can be switched on and off, for example, and / or the volume flow of the cooling air can be regulated.

[0039] Furthermore, a protected vehicle with such an exhaust silencer system is proposed.

[0040] The exhaust silencer system is arranged in particular in a front area, a rear area, or a side area of ​​the vehicle. In particular, the exhaust silencer system is placed under a floor of the vehicle. The fact that the vehicle is "protected" in this case means that the vehicle is protected against gunfire, booby traps, improvised explosive devices (IEDs), mines, or the like. The vehicle is preferably a wheeled vehicle. However, the vehicle can also be a tracked vehicle. Preferably, the vehicle is a hull-mounted vehicle. The vehicle preferably comprises a passenger compartment that is protected, in particular armored, and can accommodate crew members.

[0041] Furthermore, a method for operating such an exhaust silencer system for a protected vehicle is proposed. The exhaust silencer system comprises an exhaust silencer, a cooling air guide housing attached to the exhaust silencer, and an electrothermal converter device attached to the outside of the exhaust silencer and within the cooling air guide housing. The method comprises the following steps: a) actively extracting heat from the exhaust silencer using the converter device, and b) transferring the heat to cooling air flowing through the cooling air guide housing using the converter device, thereby influencing a heat signature of the exhaust silencer system.

[0042] By extracting heat from the exhaust silencer, the exhaust gas is cooled, resulting, for example, in a signature reduction. The fact that the converter device "actively" extracts heat means, in particular, that energy, in particular electrical energy, is supplied to the converter device to transport the heat from the exhaust silencer to the cooling air. In contrast, "passively" can dissipate the heat, for example, through thermal radiation. "Influencing" in this case means, in particular, that the heat signature is controlled and / or reduced.

[0043] According to one embodiment, the converter device can be switched from a first operating state, in which the converter device releases the heat to the cooling air flowing through the cooling air guide housing, into a second operating state, in which the converter device interrupts a heat flow from a hot side of the converter device facing the exhaust silencer to a cold side of the converter device facing away from the exhaust silencer.

[0044] In particular, in the second operating state, the heat flow from the hot side to the cold side is interrupted by reversing the polarity of a voltage applied to the converter device in the first operating state. This results in heat buildup in the exhaust silencer. The heat cannot be dissipated to the cooling air. Instead, in the second operating state, the converter device transports heat from the cooling air into the exhaust silencer.

[0045] According to a further embodiment, the converter device can be switched from the first operating state or from the second operating state into a third operating state in which the converter device converts thermal energy into electrical energy with the aid of a temperature difference between the hot side of the converter device and the cold side of the converter device.

[0046] The so-called Seebeck effect is used for this purpose. The electrical energy can be temporarily stored in the vehicle's energy storage unit. This makes it possible to extend the vehicle's operating time, particularly in the case of a hybrid vehicle. The energy storage unit can also be used to supply power to the control and / or regulation device and the converter device.

[0047] According to a further embodiment, the converter device comprises a plurality of electrothermal converter elements which are individually controlled so that a predetermined pattern is generated in the heat signature of the exhaust silencer system.

[0048] The converter elements are individually controlled using the aforementioned control and / or regulating device. Each converter element can thus be switched to the first operating state, the second operating state, or the third operating state as desired. The predefined pattern can, for example, be stored on a data storage device of the control and / or regulating device.

[0049] According to a further embodiment, the converter elements are controlled in such a way that the heat signature of the exhaust silencer system is adapted to a heat signature of an environment of the exhaust silencer system.

[0050] In particular, the heat signature of the exhaust silencer system can also be adapted to the surface on which the vehicle is traveling. For example, the heat signature of the exhaust silencer system can be adapted to a building or a vehicle in front of which the vehicle with the exhaust silencer system is parked. This allows for excellent camouflage of the vehicle. "Adapting" in this case means, in particular, that the heat signature of the exhaust silencer system is adjusted to the heat signature of the surroundings of the exhaust silencer system. As previously mentioned, the control and / or regulating device can control the converter device for this purpose based on sensor signals from the sensor system of the exhaust silencer system.

[0051] The embodiments and features described for the proposed exhaust silencer system apply accordingly to the proposed protected vehicle and / or the proposed method and vice versa.

[0052] "One" in this case is not necessarily limited to a single element. Rather, multiple elements, such as two, three, or more, may also be included. Any other counting term used here should not be understood as implying a limitation to the exact number of elements mentioned. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

[0053] Further possible implementations of the exhaust silencer system, the protected vehicle, and / or the method also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the exhaust silencer system, the protected vehicle, and / or the method.

[0054] Further advantageous embodiments and aspects of the exhaust silencer system, the protected vehicle, and / or the method are the subject of the dependent claims and the exemplary embodiments of the exhaust silencer system, the protected vehicle, and / or the method described below. The exhaust silencer system, the protected vehicle, and / or the method are explained in more detail below using preferred embodiments with reference to the accompanying figures. Fig. 1 shows a schematic side view of an embodiment of a protected vehicle; Fig. 2 shows a schematic perspective view of an embodiment of an exhaust silencer system for the protected vehicle according to Fig. 1 ; Fig. 3 shows a further schematic perspective view of the exhaust silencer system according to Fig. 2 ; Fig. 4 shows a schematic rear view of the exhaust silencer system according to Fig. 2 ; Fig. 5 shows a highly simplified schematic sectional view of the exhaust silencer system according to Fig. 2 ; and Fig. 6 shows a schematic block diagram of an embodiment of a method for operating the exhaust silencer system according to Fig. 2 .

[0055] In the figures, identical or functionally equivalent elements have been given the same reference numerals unless otherwise stated.

[0056] The Fig. 1 shows a schematic side view of an embodiment of a protected vehicle 1. The protected vehicle 1 is hereinafter referred to simply as a vehicle. The vehicle 1 can be a military vehicle, in particular a military utility vehicle. The vehicle 1 can be a hull-mounted vehicle. The vehicle 1 can be armed or unarmed.

[0057] The vehicle 1 comprises a protected passenger compartment 2. The passenger compartment 2 is protected against gunfire, booby traps, improvised explosive devices (IEDs), mines, or the like. The passenger compartment 2 encloses an interior space I in which crew members can be accommodated. The interior space I of the passenger compartment 2 can be entered and exited from an area U of the vehicle 1 via hatches or doors.

[0058] Vehicle 1 can be a wheeled vehicle. Alternatively, vehicle 1 can also be a tracked vehicle. Vehicle 1 comprises several wheel axles, each with wheels 3 and 4. The number of wheel axles is fundamentally arbitrary. For example, two, three, or four wheel axles can be provided. At least one of the wheel axles is steered. Multiple wheel axles can also be steered. Preferably, vehicle 1 has all-wheel drive. This means that all wheel axles are driven. Vehicle 1 is suitable for off-road use and can therefore also be referred to as an off-road vehicle.

[0059] The vehicle 1 has an internal combustion engine 5 for driving the wheel axles or the wheels 3, 4. The vehicle 1 can be driven exclusively by the internal combustion engine 5. Alternatively, the vehicle 1 can also be a hybrid vehicle. In this case, the vehicle 1 comprises one or more electric motors in addition to the internal combustion engine 5. In this case, the internal combustion engine 5 and the electric motor or motors are part of a hybrid drivetrain or hybrid powertrain of the vehicle 1.

[0060] With the help of the wheels 3, 4 driven by the combustion engine 5, the vehicle 1 can move in a direction of travel F on a surface O. The surface O can be a road, a gravel track, or any other type of terrain. The vehicle 1 can have a reverse gear so that it can also move in the opposite direction of travel F.

[0061] An exhaust system with an exhaust silencer system 6 is assigned to the internal combustion engine 5. The exhaust silencer system 6 can be a rear silencer. The exhaust silencer system 6 can be arranged on the side of the passenger compartment 2, in a front area, or in a rear area of ​​the passenger compartment 2. The exhaust silencer system 6 can be covered, at least in sections, by an outer shell, for example, by a side wall, of the passenger compartment 2.

[0062] The exhaust silencer system 6 generates a heat signature S or has a heat signature S. The heat signature S arises because the exhaust silencer system 6 emits heat, in particular in the form of infrared radiation. Furthermore, the heat signature S also results from heating of components of the vehicle 1 surrounding the exhaust silencer system 6, which also emit heat. The heat signature S is characteristic of the vehicle 1. This means that the vehicle 1, in particular a vehicle type of the vehicle 1, can be identified using the heat signature S.

[0063] In the Fig. 1 The heat signature S is represented in a highly simplified manner as a rectangle. The heat signature S can have any desired geometry or outline. Within this aforementioned rectangle, there are areas that emit more heat and areas that emit less heat compared to the former. This means, in particular, that there are areas where the heat flow is higher and areas where the heat flow is lower compared to the former. The heat signature S thus exhibits a characteristic pattern. The heat signature S can, for example, be recorded using an infrared sensor and displayed on a screen.

[0064] Vehicle 1 is assigned a coordinate system with a width direction or x-direction x, a height direction or y-direction y, and a depth direction or z-direction z. The directions x, y, and z are oriented perpendicular to each other. A direction of gravity g can be oriented opposite to the y-direction y. The direction of gravity g is oriented perpendicular to the surface O.

[0065] Particularly in military vehicles 1, great importance is placed on signature reduction in all aspects. In addition to the heat signature S, this can also include a noise signature, for example. The removal of hot exhaust gases from the combustion engine 5 from the vehicle 1 can be problematic in this case. Due to the generally short and direct exhaust paths, a so-called hotspot occurs at the location of an exhaust outlet, which is only immediately colder than the outlet temperature of the exhaust gas from the combustion engine 5 itself. In addition, the exhaust silencer system 6 also heats surrounding components and thus also the outer shell of the vehicle 1 itself. This heating creates a heat signature S pattern that is characteristic of the respective vehicle type and can be used by enemy reconnaissance aircraft to precisely determine the vehicle type.

[0066] In a hybrid powertrain, the combustion engine 5 is not running during the entire operation of the vehicle 1, but rather undergoes a start-stop cycle as needed. This creates the problem of recurring heat buildup in an exhaust pipe, which heats up disproportionately as a result, thus exacerbating the aforementioned hotspot problem.

[0067] According to internal company findings, attempts are therefore made to artificially lengthen the exhaust path in such vehicles 1 and surround it with a shell made of heat-insulating material. Due to the longer exhaust path, more heat is released into the environment U, which reduces the temperature of the exhaust gas at the exhaust outlet. It is also possible to mix the exhaust gas upstream of the exhaust outlet with a cooling air flow or an additional air flow from the vehicle 1.

[0068] However, the aforementioned solutions often require a lot of space and high mass. However, they only inadequately solve the actual problem of the characteristic heat signature S. In particular, after the combustion engine 5 is switched off and cooled down, the escaping residual heat can spread uncontrollably and heat the entire vehicle 1. This must be improved.

[0069] The Fig. 2 shows a schematic perspective view of an embodiment of an improved exhaust silencer system 6 for the vehicle 1. The Fig. 3 shows a further schematic perspective view of the exhaust silencer system 6. The Fig. 4 shows a schematic rear view of the exhaust silencer system 6 viewed in the opposite direction to the x-direction x. Fig. 5 shows a highly simplified schematic sectional view of the exhaust silencer system 6. The following refers to the Fig. 2 bis 5 referred to at the same time.

[0070] The exhaust silencer system 6 can be arranged on the side of the vehicle 1, in a front area or in a rear area of ​​the vehicle 1. This means that the exhaust silencer system 6 can basically be oriented in any spatial position. Fig. 2 bis 5 However, it is assumed that the exhaust silencer system 6 extends in the direction of travel F or along the x-direction x.

[0071] The exhaust silencer system 6 comprises an exhaust silencer 7, which is essentially cuboid-shaped. The exhaust silencer 7 can be a rear silencer. The exhaust silencer 7 comprises a cover 8, which faces, for example, the passenger compartment 2, and a base 9 arranged opposite the cover 8, which faces away from the passenger compartment 2 and, for example, faces the surface O.

[0072] Furthermore, the exhaust silencer 7 comprises two side walls 10, 11 arranged opposite one another, in particular a first side wall 10 and a second side wall 11. The first side wall 10 can, for example, face the passenger compartment 2 and the second side wall 11 can face away from the passenger compartment 2. At the front end, the exhaust silencer 7 is closed by a front wall 12 and a rear wall 13. The exhaust silencer 7 thus encloses a volume 14 ( Fig. 5 ), which can be divided into several chambers. In particular, the exhaust silencer 7 is a resonance silencer.

[0073] The exhaust silencer 7 further comprises an exhaust gas supply pipe 15, by means of which hot exhaust gas A from the internal combustion engine 5 can be supplied to the exhaust silencer system 6. Further components of the aforementioned exhaust system of the vehicle 1, which are not shown, can be arranged between the internal combustion engine 5 and the exhaust silencer system 6. These components can include, for example, a manifold attached to the internal combustion engine 5, a catalytic converter, a front silencer, a middle silencer, or the like.

[0074] The exhaust gas supply pipe 15 comprises an outer pipe 16 and an inner pipe 17 arranged coaxially to the outer pipe 16. An insulating air gap is provided between the outer pipe 16 and the inner pipe 17. This prevents the hot exhaust gas A from releasing heat to the environment U in the region of the exhaust gas supply pipe 15. Instead of the double-walled structure with the outer pipe 16 and the inner pipe 17, the exhaust gas supply pipe 15 can also be single-walled and have insulation on the outside. The exhaust gas supply pipe 15, in particular only the inner pipe 17 of the exhaust gas supply pipe 15, is led through the first side wall 10 into the exhaust silencer 7. Alternatively, the exhaust gas supply pipe 15 can also be led through the front wall 12 into the exhaust silencer 7, for example. The exhaust gas supply pipe 15 comprises an exhaust gas inlet 18 through which the exhaust gas A flows into the exhaust gas supply pipe 15, in particular into the inner pipe 17.

[0075] In addition to the exhaust gas supply pipe 15, the exhaust silencer 7 comprises an exhaust gas discharge pipe 19, which, for example, leads out of the exhaust silencer 7 at the rear wall 13. The exhaust gas supply pipe 15 and the exhaust gas discharge pipe 19 are not directly connected to one another. As previously mentioned, the volume 14 can be divided into a plurality of chambers. For example, the exhaust gas supply pipe 15, in particular the inner pipe 17 of the exhaust gas supply pipe 15, opens into one of the chambers, and the exhaust gas discharge pipe 19 opens into another of the chambers. The exhaust gas A then flows from the exhaust gas supply pipe 15 via the individual chambers to the exhaust gas discharge pipe 19.

[0076] In particular, the exhaust gas A is dammed in the exhaust silencer 7 to homogenize the flow of the exhaust gas A. The sound is reflected in the chambers, on the cover 8, the base 9, the side walls 10, 11, the front wall 12, and the rear wall 13, thereby reducing noise. The exhaust gas discharge pipe 19 includes an exhaust outlet 20 through which the exhaust gas A leaves the exhaust silencer 7 again. The hot exhaust gas A heats the exhaust silencer 7.

[0077] The exhaust silencer system 6 comprises, in addition to the exhaust silencer 7, a cooling air guide housing 21, which is Fig. 3 not shown. The cooling air guide housing 21 is firmly connected to the exhaust silencer 7. For example, the cooling air guide housing 21 is screwed, riveted, or welded to the exhaust silencer 7. The cooling air guide housing 21 covers the base 9, the second side wall 11, and the front wall 12 at least in sections.

[0078] The cooling air guide housing 21 comprises a side wall 22, which is arranged, for example, parallel to the second side wall 11 of the exhaust silencer 7 and spaced therefrom. Furthermore, the cooling air guide housing 21 comprises a base 23, which is spaced from and parallel to the base 9 of the exhaust silencer 7. The cooling air guide housing 21 can also be configured to additionally enclose the cover 8 and / or the first side wall 10.

[0079] On the front side, i.e. assigned to the front wall 12, the cooling air guide housing 21 comprises a cooling air distributor 24 for the uniform distribution of cooling air L, which is supplied to the cooling air distributor 24 via a cooling air inlet 25. The cooling air L can be supplied to the cooling air inlet 25, for example, passively by the airstream when the vehicle 1 is moving in the direction of travel F. However, a ventilation device 26 is particularly preferably provided, which enables a forced flow of the cooling air L through the cooling air guide housing 21. The ventilation device 26 can, for example, be an electrically driven fan, which supplies the cooling air L to the cooling air inlet 25 via suitable piping.

[0080] The cooling air guide housing 21 further comprises a cooling air collector 27 with a cooling air outlet 28, from which the cooling air L exits the cooling air guide housing 21. As the Fig. 4 shows, the cooling air outlet 28 is kidney-shaped or curved and runs at least partially around the exhaust outlet 20 of the exhaust silencer 7. As a result, the cooling air L exiting from the cooling air outlet 28 forms a cooling air curtain that extends at least partially around the hot exhaust gas A flowing out of the exhaust outlet 20, which shields the exhaust gas A. Furthermore, with this arrangement, a suitable mixing of the exhaust gas A with the cooling air L can only be achieved at a certain distance from the exhaust outlet 20.

[0081] As the Fig. 5 shows, a cooling air duct 29 is formed between the exhaust silencer 7, in particular between the bottom 9 and the second side wall 11 of the exhaust silencer 7, and the cooling air guide housing 21, through which the cooling air L flows. In the Fig. 5 the cooling air guide housing 21 is shown only in a very simplified manner and does not cover the base 9.

[0082] The exhaust silencer system 6 comprises an electrothermal converter device 30 mounted on the outside of the exhaust silencer 7 and within the cooling air guide housing 21. The converter device 30 is suitable for extracting heat W from the exhaust silencer 7 and thus indirectly from the exhaust gas A and transferring it to the cooling air L. Conversely, the converter device 30 is also suitable for extracting heat W from the cooling air L and transferring it to the exhaust silencer 7. Furthermore, the converter device 30 can also be suitable for converting heat W into electrical energy with the aid of a temperature difference between the exhaust silencer 7 and the cooling air L.

[0083] The converter device 30 is arranged in the cooling air duct 29. The converter device 30 covers, for example, the base 9 and the second side wall 11 of the exhaust silencer 7 at least in sections. Two converter devices 30 can be provided, one located on the base 9 and the other on the second side wall 11. Furthermore, the converter device 30 can also be provided on the cover 8, the first side wall 10, the front wall 12 and / or the rear wall 13 of the exhaust silencer 7. In particular, the cover 8, the first side wall 10, the front wall 12 and / or the rear wall 13 can each be assigned a separate converter device 30.

[0084] However, the following assumes only one converter device 30. The converter device 30 comprises a plurality of electrothermal converter elements 31, of which Fig. 5 only one is shown. The number of transducer elements 31 is essentially arbitrary. Only one transducer element 31 will be discussed below.

[0085] For example, the converter element 31 has dimensions of 20 to 90 mm x 20 to 90 mm and a thickness of 3 to 5 mm. The converter element 31 comprises a hot side 32 facing the exhaust silencer 7 and a cold side 33 facing away from the exhaust silencer 7. A layer of a material with high thermal conductivity 34, in particular a layer of thermal paste, is provided between the hot side 32 and the exhaust silencer 7. The material with high thermal conductivity 34 ensures good heat transfer from the exhaust silencer 7 to the hot side 32. The term "material with high thermal conductivity" can be replaced by the term "thermal paste," and vice versa.

[0086] A heat sink 35 is provided on the cold side 33 and extends into the cooling air duct 29. Each converter element 31 can comprise its own heat sink 35. However, preferably, several converter elements 31 share a common heat sink 35. For example, all converter elements 31 provided on the second side wall 11 can have a common heat sink 35. Accordingly, all converter elements 31 provided on the base 9 can also comprise a common heat sink 35.

[0087] The heat sink 35 comprises a plate-shaped base section 36 and a plurality of cooling fins 37 extending from the base section 36, between which the cooling air L flows. The heat sink 35 can be made of aluminum, for example. A further layer of the material with high thermal conductivity 38, in particular a further layer of thermal paste, is provided between the cold side 33 and the heat sink 35, in particular the base section 36 of the heat sink 35. The material with high thermal conductivity 38 ensures good heat transfer from the cold side 33 to the heat sink 35.

[0088] The exhaust silencer system 6 further comprises a control and / or regulating device 39 for controlling the converter device 30. The control and / or regulating device 39 can also be suitable for controlling the ventilation device 26, for example, switching it on and off and / or regulating a volume flow of the cooling air L. The control and / or regulating device 39 is particularly suitable for controlling each converter element 31 individually. "Individually" in this case means, in particular, that the control and / or regulating device 39 can control each converter element 31 independently of all other converter elements 31, as will be explained below. For example, the converter element 31 can be controlled by the control and / or regulating device 39 applying a voltage to the converter element 31.

[0089] The exhaust silencer system 6 can be covered at least in sections by an outer shell 40, in particular a side wall of the outer shell 40. The exhaust silencer 7 can heat the outer shell 40 at least in sections, causing it to radiate heat and thus contribute to the heat signature S. The outer shell 40 can be open toward the surface O.

[0090] The functionality of the exhaust silencer system 6 is explained below. With the aid of the converter device 30, it is possible to influence, particularly reduce, or control the heat signature S of the exhaust silencer system 6, in particular of the exhaust silencer 7. In this case, the "heat signature" can be understood as the thermal radiation or infrared radiation that can be detected and displayed by a photoreceiver of a thermal imaging device.

[0091] As previously mentioned, each vehicle type of vehicle 1 has a characteristic heat signature S. Because the converter device 30 influences the heat signature S of the exhaust silencer system 6, in particular the exhaust silencer 7, either this characteristic assignment is no longer possible or the vehicle 1 can no longer be detected at all. In this latter case, infrared camouflage is implemented in the form of a stealth technology.

[0092] In the Fig. 5 The temperature T is plotted diagrammatically against the z-direction z. The hot exhaust gas A, which has a temperature of up to 700 °C, is guided through the exhaust gas supply pipe 15 into the exhaust silencer 7. The exhaust silencer 7 dams up the exhaust gas A to homogenize the flow of the exhaust gas A, whereby the exhaust silencer 7 heats up over the duration of the operation of the internal combustion engine 5. A schematic curve of the temperature T shows only a slight cooling of the temperature of the exhaust gas A from the exhaust gas supply pipe 15 to the side walls 10, 11 of the exhaust silencer 7 in this region.

[0093] With the aid of the control and / or regulating device 39, it is possible to place the converter device 30 in different operating states. In a first operating state, which is Fig. 5 As shown, the converter element 31 is subjected to a voltage which increases the transport of heat W from the hot side 32 to the cold side 33. In this case, the converter element 31 transfers the heat W to the cooling air L flowing through the cooling air duct 29 via the heat sink 35. As the diagram according to the Fig. 5 shows, the temperature T drops across the converter element 31 and the cooling air duct 29, so that the cooling air guide housing 21 has a significantly lower temperature T than the exhaust gas A flowing into the exhaust silencer 7.

[0094] The exhaust gas A or the exhaust silencer 7 is actively cooled. "Active" in this case means that by applying voltage to the converter element 31, the heat W is extracted from the exhaust gas A or the exhaust silencer 7 and transferred to the cooling air L via the heat sink 35. "Active" also means, in particular, that energy is used to transport the heat W away from the exhaust silencer 7.

[0095] The exhaust gas A is thus actively cooled and exits the exhaust outlet 20 at a significantly lower temperature T compared to an exhaust silencer system without such a converter device 30. At the same time, the heated cooling air L, which is, however, even cooler than the cooled exhaust gas A, exits the cooling air outlet 28. The escaping cooling air L shields the warmer exhaust gas A like a curtain due to the curved geometry of the cooling air outlet 28.

[0096] In a second operating state, which differs from the first operating state, the converter device 30 interrupts a heat flow from the hot side 32 to the cold side 33. This can be achieved by reversing the polarity of the voltage applied to the converter element 31 in the first operating state. In particular, heat W can also be transferred from the cooling air L to the exhaust silencer 7 in the second operating state.

[0097] By largely preventing heat transfer from the exhaust silencer 7, the heat W is retained in the exhaust silencer 7 and thus cannot heat the outer shell 40 of the vehicle 1. This is particularly advantageous in a hybrid vehicle in which the combustion engine 5 is operated in start-stop cycles.

[0098] With the aid of the control and / or regulating device 39, the converter device 30 can be switched from the first operating state or from the second operating state to a third operating state that differs from the first operating state and the second operating state. In this third operating state, the converter device 30 converts thermal energy into electrical energy using the temperature difference between the hot side 32 and the cold side 33. The so-called Seebeck effect is utilized here.

[0099] In the third operating state, the converter element 31 acts as a thermoelectric generator, which converts the thermal energy into electrical energy due to the resulting temperature difference between the exhaust silencer 7 and the heat sink 35. By removing the heat W, the temperature of the exhaust gas A can also be reduced. However, the reduction in the temperature of the exhaust gas A is not as great in the third operating state as in the first operating state.

[0100] The generated electrical energy can be temporarily stored in an energy storage device 41, for example, an accumulator, of the vehicle 1. The energy storage device 41 can also be used to supply energy to the control and / or regulating device 39 and / or the converter device 30. Due to the effect of the thermoelectric generator, a portion of the energy converted into heat W can be recovered. In the event that the vehicle 1 is a hybrid vehicle, this effect can be used particularly to extend the purely electric operation. This can, for example, advantageously extend the service life of the vehicle 1.

[0101] If vehicle 1 is deployed and in a fixed position, the ability to reduce and / or control the thermal signature contributes significantly to the survivability of vehicle 1 and its crew members. This actively prevents thermal hotspots on vehicle 1 from revealing both its position and its identity. The use of the exhaust silencer system 6 can therefore have a positive impact on both the safety and duration of an operation.

[0102] As previously mentioned, the transducer elements 31 can be individually controlled. Thus, it is possible to generate a predetermined pattern in the heat signature S of the exhaust silencer 7 with the aid of the control and / or regulating device 39. The predetermined pattern can, for example, be a heat signature of another vehicle type stored in the control and / or regulating device 39. Thus, deception regarding the identity of the vehicle 1 is possible. Furthermore, it is also possible to control the transducer elements 31 such that the heat signature S of the exhaust silencer system 6, in particular of the exhaust silencer 7, adapts to a heat signature of the environment U and / or the surface O. For example, the heat signature S of the exhaust silencer system 6 can adapt to a building or another vehicle in front of which the vehicle 1 is parked.

[0103] The exhaust silencer system 6 can comprise a sensor system 42 that can detect the heat signature of the environment U and / or the surface O. The sensor system 42 can comprise an infrared sensor. The sensor system 42 can provide sensor signals to the control and / or regulating device 39. The control and / or regulating device 39 can then control the converter device 30 based on the sensor signals such that the heat signature S of the exhaust silencer system 6 adapts to the heat signature of the environment U and / or the surface O.

[0104] The Fig. 6shows a schematic block diagram of an embodiment of a method for operating the exhaust silencer system 6. In the method, in a step S1, heat W is actively extracted from the exhaust silencer 7 and thus from the exhaust gas A with the aid of the converter device 30. In a step S2, the heat W is transferred to the cooling air L flowing through the cooling air guide housing 21. This is done with the aid of the heat sink 35. By actively extracting the heat W, the heat signature S of the exhaust silencer system 6 can be influenced. The active extraction of the heat W takes place in the first operating state of the converter device 30.

[0105] As previously mentioned, in the second operating state of the converter device 30, the heat flow from the hot side 32 of the converter device 30 facing the exhaust silencer 7 to the cold side 33 of the converter device 30 facing away from the exhaust silencer 7 is interrupted. This can be achieved by reversing the polarity of a voltage with which the converter device 30 or the converter elements 31 are energized in the first operating state. In particular, heat W can also be transferred from the cooling air L to the exhaust silencer 7 in the second operating state.

[0106] In the third operating state, thermal energy is converted into electrical energy with the aid of the converter device 30 due to the temperature difference between the hot side 32 of the converter device 30 and the cold side 33 of the converter device 30 or the converter elements 31. This electrical energy can be temporarily stored in the energy storage device 41.

[0107] By individually controlling the transducer elements 31 of the transducer device 30, a predetermined pattern can be generated in the heat signature S of the exhaust silencer system 6, in particular of the exhaust silencer 7. In particular, the heat signature S of the exhaust silencer system 6 can be adapted to the heat signature of the environment U and / or the surface O. This allows for infrared camouflage of the vehicle 1.

[0108] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. LIST OF REFERENCE SYMBOLS

[0109] 1Vehicle 2Passenger compartment 3Wheel 4Wheel 5Combustion engine 6Exhaust silencer system 7Exhaust silencer 8Cover 9Floor 10Side wall 11Side wall 12Front wall 13Rear wall 14Volume 15Exhaust supply pipe 16Outer pipe 17Inner pipe 18Exhaust inlet 19Exhaust discharge pipe 20Exhaust outlet 21Cooling air duct housing 22Side wall 23Floor 24Cooling air distributor 25Cooling air inlet 26Ventilation device 27Cooling air collector 28Cooling air outlet 29Cooling air duct 30Electrothermal converter device 31Electrothermal converter element 32Hot side 33Cold side 34Material with high thermal conductivity 35Heat sink 36Base section 37Cooling fin 38Material with high thermal conductivity 39Control and / or regulating device 40Outer shell 41Energy storage 42Sensors AExhaust gas FDirection of travel gDirection of gravity IInterior LCooling air OSSurface SWet signature S1Step S2Step TTemperature UAmbient WHeat xx-direction yy-direction zz-direction

Claims

1. Exhaust gas muffler system (6) for a protected vehicle (1), comprising an exhaust gas muffler (7), a cooling air guidance housing (21) mounted at the exhaust gas muffler (7), and an electrothermal converter apparatus (30) mounted at an outside of the exhaust gas muffler (7) and mounted within the cooling air guidance housing (21) for actively extracting heat (W) from the exhaust gas muffler (7) which the converter apparatus (30) delivers to cooling air (L) flowing through the cooling air guidance housing (21) to affect a heat signature (S) of the exhaust gas muffler system (6).

2. Exhaust gas muffler system according to claim 1, characterized in that the converter apparatus (30) can be switched from a first operating state, in which the converter apparatus (30) emits the heat (W) to the cooling air (L) flowing through the cooling air guidance housing (21), to a second operating state in which the converter apparatus (30) interrupts a heat flow from a hot face (32) of the converter apparatus (30) facing the exhaust gas muffler (7) to a cold face (33) of the converter apparatus (30) facing away from the exhaust gas muffler (7).

3. Exhaust gas muffler system according to claim 2, characterized in that the converter apparatus (30) can be switched from the first operating state or from the second operating state to a third operating state in which the converter apparatus (30) converts thermal energy into electrical energy with the aid of a temperature difference between the hot face (32) of the converter apparatus (30) and the cold face (33) of the converter apparatus (30).

4. Exhaust gas muffler system according to any one of claims 1 - 3, characterized in that the converter apparatus (30) comprises a plurality of electrothermal converter elements (31) which are individually controllable to generate a predetermined pattern in the heat signature (S) of the exhaust gas muffler system (6).

5. Exhaust gas muffler system according to claim 4, characterized in that the converter elements (31) can be controlled in such a way that the heat signature (S) of the exhaust gas muffler system (6) adapts to a heat signature of a surroundings (U) of the exhaust gas muffler system (6).

6. Exhaust gas muffler system according to any one of claims 1 - 5, characterized in that the converter apparatus (30) comprises a heat sink (35) which projects into a cooling air duct (29) provided between the exhaust gas muffler (7) and the cooling air guidance housing (21).

7. Exhaust gas muffler system according to any one of claims 1 - 6, characterized in that the converter apparatus (30) is mounted to a bottom (9) and to a side wall (11) of the exhaust gas muffler (7).

8. Exhaust gas muffler system according to any one of claims 1 - 7, characterized in that the exhaust gas muffler (7) comprises an exhaust gas outlet (20), wherein the cooling air guidance housing (21) comprises a cooling air outlet (28), and wherein the cooling air outlet (28) is guided around the exhaust gas outlet (20) at least in sections.

9. Exhaust gas muffler system according to any one of claims 1 - 8, characterized in that the cooling air guidance housing (21) comprises a cooling air distributor (24) for uniformly distributing the cooling air (L) to the converter apparatus (30), wherein it is possible for the cooling air (L) to be fed to the cooling air distributor (24) with the aid of a cooling air inlet (25) of the cooling air guidance housing (21).

10. Protected vehicle (1) comprising an exhaust gas muffler system (6) according to any of claims 1 - 9.

11. Method for operating an exhaust gas muffler system (6) for a protected vehicle (1), wherein the exhaust gas muffler system (6) comprises an exhaust gas muffler (7), a cooling air guidance housing (21) mounted at the exhaust gas muffler (7), and an electrothermal converter apparatus (30) mounted at an outside of the exhaust gas muffler (7) and mounted within the cooling air guidance housing (21), comprising the following steps: a) actively extracting (S1) heat (W) from the exhaust gas muffler (7) with the aid of the converter apparatus (30), and b) releasing (S2) the heat (W) to cooling air (L) flowing through the cooling air guidance housing (21) with the aid of the converter apparatus (30), thereby affecting a heat signature (S) of the exhaust gas muffler system (6).

12. Method according to claim 11, characterized in that the converter apparatus (30) can be switched from a first operating state, in which the converter apparatus (30) emits the heat (W) to the cooling air (L) flowing through the cooling air guidance housing (21), to a second operating state in which the converter apparatus (30) interrupts a heat flow from a hot face (32) of the converter apparatus (30) facing the exhaust gas muffler (7) to a cold face (33) of the converter apparatus (30) facing away from the exhaust gas muffler (7).

13. Method according to claim 12, characterized in that the converter apparatus (30) can be switched from the first operating state or from the second operating state to a third operating state in which the converter apparatus (30) converts thermal energy into electrical energy with the aid of a temperature difference between the hot face (32) of the converter apparatus (30) and the cold face (33) of the converter apparatus (30).

14. Method according to any one of claims 11 - 13, characterized in that the converter apparatus (30) comprises a plurality of electrothermal converter elements (31) which are individually controlled so that a predetermined pattern is produced in the heat signature (S) of the exhaust gas muffler system (6).

15. Method according to claim 14, characterized in that the converter elements (31) are controlled in such a way that the heat signature (S) of the exhaust gas muffler system (6) is adapted to a heat signature of a surroundings (U) of the exhaust gas muffler system (6).

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