Vehicle with a fuel cell system and method for operating a fuel cell system in a vehicle

Abstract

A vehicle comprises a fuel cell system (10) with a fuel cell arrangement (14) and a fuel cell exhaust system (20) receiving fuel cell exhaust gas (AB) from the fuel cell arrangement (14), wherein the fuel cell exhaust system (20) has a fuel cell exhaust gas outlet area (34) for releasing fuel cell exhaust gas (AB) from the fuel cell exhaust system (20) and an ambient air heating arrangement (38) for heating ambient air (U) to be mixed with at least a part of the fuel cell exhaust gas (AB), wherein the ambient air heating arrangement (38) has an ambient air outlet area (42) for releasing ambient air (UE) heated in the ambient air heating arrangement (38).The fuel cell exhaust gas outlet area (34) is positioned downstream of the ambient air outlet area (42) with respect to an ambient air flow direction (Us) of the heated ambient air (UE) discharged at the ambient air outlet area (42) by the ambient air heating arrangement (38).

Description

The present invention relates to a vehicle having a fuel cell system and to a method for operating a fuel cell system in a vehicle.In a fuel cell system used in a vehicle for generating electrical energy, when converting anode gas supplied from an anode region of a fuel cell arrangement and containing hydrogen (H 2) and cathode gas supplied to a cathode region of the fuel cell arrangement and containing oxygen (O 2) depending on the type of fuel cell arrangement used, an anode off-gas enriched comparatively strongly with water or water vapor or / and a cathode off-gas enriched comparatively strongly with water or water vapor are produced. If such fuel cell exhaust gas, which is highly enriched with water or water vapor and contains or comprises the anode exhaust gas and / or the cathode exhaust gas, is discharged to the environment at a comparatively low ambient temperature, intensive mist formation can occur at the outlet location of the fuel cell exhaust gas as a result of condensing water when the water-containing fuel cell exhaust gas contacts the comparatively cold ambient air. This is not only undesirable for visual reasons, but there is the risk that ice is formed by the water condensing out at low ambient temperature and in particular cold subsurface and precipitating on the subsurface.From the post-published German patent application DE 10 2023 108 806, a fuel cell exhaust gas system is known in which water or water vapor-containing fuel cell exhaust gas is mixed with ambient air heated at an ambient air heating arrangement in a fuel cell exhaust gas / ambient air mixing arrangement integrated into the fuel cell exhaust gas system. The fuel cell exhaust gas / ambient air mixing arrangement comprises a mixing volume formed in a mixing chamber, into which the heated ambient air and the fuel cell exhaust gas are introduced. After the fuel cell exhaust gas has been mixed with the ambient air, the mixture of fuel cell exhaust gas and heated ambient air formed in the mixing volume is discharged from the mixing chamber to the environment via a part of a fuel cell exhaust gas system situated downstream of the mixing chamber at an outlet opening of the fuel cell exhaust gas system. In the region of the outlet opening of the fuel cell exhaust system, the mixture of fuel cell exhaust gas and heated ambient air mixes with the non-heated ambient air.It is the object of the present invention to provide a vehicle with a fuel cell system and a method for operating a fuel cell system in a vehicle, with which the risk of mist formation during the discharge of fuel cell exhaust gas into the environment can be effectively counteracted.According to a first aspect of the present invention, this object is achieved by a vehicle comprising:a fuel cell system having a fuel cell arrangement and a fuel cell exhaust system receiving fuel cell exhaust gas from the fuel cell arrangement, wherein the fuel cell exhaust system has a fuel cell exhaust gas outlet region for discharging fuel cell exhaust gas from the fuel cell exhaust system,an ambient air heating arrangement for heating ambient air to be mixed with at least a portion of the fuel cell exhaust gas, wherein the ambient air heating arrangement has an ambient air outlet region for discharging ambient air heated in the ambient air heating arrangement.In an embodiment of a vehicle according to the invention, the fuel cell exhaust gas outlet region is positioned downstream of the ambient air outlet region with respect to an ambient air flow direction of the heated ambient air emitted at the ambient air outlet region by the ambient air heating arrangement. This means that the heated ambient air leaving the ambient air heating arrangement can flow around the fuel cell exhaust gas outlet region and thus a mixing of fuel cell exhaust gas and heated ambient air is brought about or supported.In an alternative configuration of a vehicle according to the invention, the fuel cell exhaust gas outlet region is positioned upstream of the ambient air outlet region with respect to the ambient air flow direction of the heated ambient air emitted at the ambient air outlet region by the ambient air heating arrangement. In this embodiment, it can be provided that the fuel cell exhaust gas discharged at the fuel cell exhaust gas outlet region flows around the ambient air heating arrangement, but is not heated in the ambient air heating arrangement, and is mixed with the ambient air discharged from it in a heated manner.In a further alternative configuration according to the invention, which can also be realized in the previously explained alternative configurations of a vehicle, the fuel cell exhaust gas outlet region and the ambient air outlet region are positioned in such a way that a stream of fuel cell exhaust gas emitted at the fuel cell exhaust gas outlet region and a stream of heated ambient air emitted at the ambient air outlet region penetrate one another at least in regions. In this embodiment, for example, the two gas streams can be conducted essentially parallel or angled relative to one another in essentially the same volume region, so that these gas streams penetrate one another and the fuel cell exhaust gas is thereby mixed with the heated ambient air.Because, in a vehicle constructed according to the invention, heated ambient air is mixed with the fuel cell exhaust gas which is highly enriched with water or water vapor, it becomes possible to provide this mixture with a relative humidity of significantly less than 100% before the fuel cell exhaust gas or the mixture generated from the fuel cell exhaust gas and the heated ambient air is discharged. If this mixture comes into contact with comparatively cold ambient air at a relative humidity that is significantly reduced in comparison with the fuel cell exhaust gas during the discharge from the fuel cell exhaust gas system, the risk that the relative humidity reaches or exceeds a value of 100% as a result of spontaneous cooling of the mixture and therefore mist formation occurs is significantly reduced. Since in the vehicle constructed according to the invention the heated ambient air is mixed with the fuel cell exhaust gas discharged from the fuel cell exhaust gas system, it is not necessary to integrate system regions in the fuel cell exhaust gas system which serve for the mixing of fuel cell exhaust gas and heated ambient air. The fuel cell exhaust system can thus be of conventional design, wherein only the fuel cell exhaust gas outlet region thereof is positioned on the vehicle or in the vehicle such that the fuel cell exhaust gas emerging from the fuel cell exhaust system and the heated ambient air are discharged into the same volume region, for example in the vehicle or in a region outside the vehicle.In order to be able to heat the ambient air to be mixed with the fuel cell exhaust gas in an efficient manner without additional energy input or without using electrical energy generated in a fuel cell system, it is proposed that the ambient air heating arrangement comprises at least one heat exchanger through which the ambient air to be heated and a cooling medium flowing in a cooling circuit can flow for transferring heat contained in the cooling medium to the ambient air to be heated.If a plurality of cooling circuits are provided in a vehicle, for example in order to be able to cool different system regions of the vehicle, such as the electronics on the one hand or a fuel cell arrangement on the other hand, independently of one another and to be able to hold these independently of one another at different temperature levels, the ambient air heating arrangement can comprise a plurality of heat exchangers through which the ambient air to be heated can flow serially. In this case, for efficient heating of the ambient air, the fuel cell exhaust gas outlet region can be positioned, for example, downstream of a heat exchanger of the plurality of heat exchangers which is positioned furthest downstream with respect to a flow direction of the ambient air to be heated.In order to achieve a regulation of the temperature of the heated ambient air, which is also adapted in particular to the water content of the fuel cell exhaust gas, a flow throttle arrangement for throttling the quantity of the ambient air to be heated flowing through the ambient air heating arrangement can be assigned to the ambient air heating arrangement.For the discharge of the fuel cell exhaust gas into a volume region outside the fuel cell exhaust gas system, the fuel cell exhaust gas outlet region can have at least one fuel cell exhaust gas outlet opening.The efficient mixing of fuel cell exhaust gas and heated ambient air can be supported, for example, by the following:at least one, preferably each, fuel cell exhaust gas outlet opening is designed for discharging fuel cell exhaust gas in a fuel cell exhaust gas flow direction substantially corresponding to the ambient air flow direction, and / orat least one, preferably each fuel cell exhaust gas outlet opening is designed for discharging fuel cell exhaust gas in a fuel cell exhaust gas flow direction substantially opposite the ambient air flow direction, and / orat least one, preferably each fuel cell exhaust gas outlet opening is designed for discharging a fuel cell exhaust gas stream expanded in a fan-like or cone-like manner.In this context, it should be pointed out that the ambient air flow direction or the fuel cell exhaust gas flow direction is used to respectively address that flow direction or main flow direction which the ambient air or the fuel cell exhaust gas has primarily or on average at the location of the respective discharge.To further assist the mixing of heated ambient air and fuel cell exhaust gas, a mixing arrangement having at least one ambient air / fuel cell exhaust gas mixer can be arranged downstream of the fuel cell exhaust gas outlet region with respect to the ambient air flow direction.In order to be able to achieve a mixing of heated ambient air and fuel cell exhaust gas leading to a reduction in relative humidity even before the heated ambient air and the fuel cell exhaust gas are discharged to the environment, that is to say in non-heated ambient air, it is proposed that the ambient air outlet region be arranged for discharging heated ambient air into an assembly space of the vehicle which is open to the environment via at least one opening region, and that the fuel cell exhaust gas outlet region be arranged for discharging fuel cell exhaust gas into the assembly space. Such a unit space can be a space or a volume area in the vehicle, in which other system areas are also arranged, such as for example a drive motor, the ambient air heating arrangement, parts of the vehicle electronics and the like.In order to be able to ensure an essentially uniform mixing of fuel cell exhaust gas and heated ambient air before it exits to the environment in the aggregate space, it is advantageous if a distance of the fuel cell exhaust gas outlet region from the ambient air outlet region is less than 50%, preferably less than 10%, of a distance of the at least one opening region from the ambient air outlet region.In order to achieve a sufficient flow through the ambient air heating arrangement with ambient air to be heated, for example when the vehicle is stationary or moving only slowly, or when positioning the ambient air heating arrangement in a region of the vehicle which is not directly exposed to the flow even when the vehicle is moving, it is proposed in an independent aspect of the invention, which can of course be combined with the aspects of the invention explained above or below, that an ambient air blower for conveying ambient air to be heated or / and heated ambient air be assigned to the ambient air heating arrangement. If the ambient air blower is arranged downstream of the ambient air heating arrangement, for example upstream of the fuel cell exhaust gas outlet region, with respect to the ambient air flow direction, the ambient air blower simultaneously generates a swirling of the heated ambient air contributing to better mixing with fuel cell exhaust gas.A particularly efficient mixing of heated ambient air and fuel cell exhaust gas can be achieved by utilizing the delivery effect of the ambient air blower when the ambient air blower is arranged downstream of the fuel cell exhaust gas outlet region with respect to the ambient air flow direction.The fuel cell exhaust system can comprise a fuel cell exhaust treatment arrangement having at least one of the following assemblies:liquid separators,catalyst,- Silencer.The invention further relates to a method for operating a fuel cell system in a vehicle, preferably a vehicle constructed according to the invention, in which method a mixture of ambient air and fuel cell exhaust gas emitted at a fuel cell exhaust gas outlet region of a fuel cell exhaust gas system assigned to a fuel cell arrangement of the fuel cell system is generated, wherein at least a portion of the ambient air mixed with the fuel cell exhaust gas is heated before mixing with the fuel cell exhaust gas.The heated ambient air and the fuel cell exhaust gas can be discharged into an assembly space of the vehicle which is open to the environment in order to achieve uniform mixing, such that the mixture of fuel cell exhaust gas and heated ambient air is formed substantially in the assembly space even before contact with the non-heated ambient air surrounding the vehicle.The ambient air to be mixed with the fuel cell exhaust gas can be heated in at least one heat exchanger by thermal interaction with a cooling medium flowing in a cooling circuit of the vehicle.In order to set a temperature of the ambient air to be heated in the at least one heat exchanger, a mass flow of the ambient air flowing through the at least one heat exchanger and / or a mass flow of the cooling medium flowing through the at least one heat exchanger can be changed.The present invention will be described in detail below with reference to the accompanying drawings. It shows: FIG. 1 shows a schematic illustration of a vehicle with a fuel cell system; FIG. 2 shows an alternative embodiment of an ambient air heating arrangement; FIG. 3 shows an alternative embodiment of the vehicle.FIG. 1 shows a fuel cell system, generally designated 10, which can be used in a vehicle 12 for providing electrical energy. The fuel cell system 10 comprises a fuel cell arrangement 14, which can be constructed, for example, with one or more fuel cell stacks and fundamentally comprises an anode region 16 fed with hydrogen-containing anode gas G A and a cathode region 18 fed with oxygen-containing cathode gas G K. In the fuel cell process, electric energy is generated on the one hand by reacting the anode gas G A and the cathode gas G K and on the other hand an anode off-gas A A generally containing residual hydrogen and a cathode off-gas A K generally containing residual oxygen are generated. Depending on the type of fuel cell, the anode off-gas A A or the cathode off-gas A K primarily contains a comparatively high proportion of water or water vapor with a relative humidity in the range of up to 90 to 100%.Associated with the fuel cell assembly 14 is a fuel cell exhaust system, generally designated 20. In the example shown, the fuel cell exhaust system 20 receives the anode exhaust gas A A and the cathode exhaust gas A K as the fuel cell exhaust gas A B. Alternatively, the fuel cell exhaust system 20 could be constructed such that it only receives that of the two exhaust gas streams leaving the fuel cell arrangement 14 which is enriched strongly or more strongly with water or water vapor.In an upstream region of the fuel cell exhaust system 20, a fuel cell exhaust treatment arrangement 22 may be provided. The fuel cell exhaust gas treatment arrangement 22 can comprise, for example, a liquid separator 24, in which, for example, larger liquid accumulations or liquid droplets contained in the fuel cell exhaust gas A B can be separated out and can be supplied to the fuel cell process, for example. The fuel cell exhaust gas treatment arrangement 22 can comprise a catalytic converter 26 for the aftertreatment of the fuel cell exhaust gas A B and can have a sound damper 28, for example.It should be noted that other or additional assemblies of the fuel cell exhaust treatment assembly 22 may be provided, or individual ones of the three illustrated assemblies of the fuel cell exhaust treatment assembly 22 may not be present in the fuel cell exhaust system 20 or may be positioned in another order.The fuel cell exhaust system 20 further comprises a fuel cell exhaust gas outlet region 34 downstream of the fuel cell exhaust gas treatment arrangement 22, In the fuel cell exhaust gas outlet region 34, the fuel cell exhaust system 20 has at least one fuel cell exhaust gas outlet openings 32, in the illustrated embodiment example a plurality of fuel cell exhaust gas outlet openings 32, via which the fuel cell exhaust gas A B leaves the fuel cell exhaust system 20. For example, the fuel cell exhaust gas outlet region 34 can comprise a tube-like end section 30 of the fuel cell exhaust gas system 20, in which a plurality of the fuel cell exhaust gas outlet openings 32 are arranged in succession in its longitudinal direction, that is to say also in the flow direction, and / or are arranged distributed around its circumference.In the exemplary embodiment illustrated in FIG. 1, the fuel cell exhaust gas outlet region 34 is positioned such that the fuel cell exhaust gas A is discharged in B into a volume which provides, for example, an assembly space 36 in the vehicle 12. Other system regions of the vehicle 12, such as, for example, an electric drive motor of the vehicle 12 supplied from the fuel cell arrangement 14 or a battery, components of the vehicle electronics or also an ambient air heating arrangement 38 explained below, can be arranged in the assembly space 36. The aggregate chamber 36 is basically not a volume enclosed in the vehicle 12, but is generally open to the outside, i.e. to the environment, via a plurality of opening areas 40. Access to the assembly space 36 can be obtained via a movable end flap, for example a bonnet or the like.The ambient air heating arrangement 38 serves to receive ambient air U and to discharge it as heated ambient air U E at an ambient air outlet region 42. In an advantageous embodiment, the ambient air heating arrangement 38 comprises a heat exchanger 44, through which a cooling medium, generally a liquid cooling medium, flows, which is assigned to the fuel cell arrangement 14, for example, and circulates by this cooling circuit absorbing heat. For example, the heat exchanger 44 can be provided by a vehicle radiator which is present in the vehicle 12 and through which the relative wind can flow. In the heat exchanger 28, the ambient air U taken in from the outside takes up heat from the cooling medium and then flows as heated ambient air U E into the unit space 36.The fuel cell exhaust gas outlet region 34 of the fuel cell exhaust gas system 20 is arranged downstream of the heat exchanger 38 or the ambient air outlet region 42 with respect to an ambient air flow direction Su. The heated ambient air U E leaving the ambient air heating arrangement 38 thus flows in the ambient air flow direction Su onto the fuel cell exhaust gas outlet region 34 of the fuel cell exhaust gas system 20 or flows into a volume region, into which the fuel cell exhaust gas A B is also discharged from the fuel cell exhaust gas outlet region 34. In this volume range, i.e. in the aggregate space 36 in the illustrated embodiment example, the fuel cell exhaust gas A B and the heated ambient air U E, thus mix, so that a mixture G of fuel cell exhaust gas A B and heated ambient air U E is formed.FIG. 1 illustrates various configurations of the fuel cell exhaust gas outlet region 34 and of the fuel cell exhaust gas outlet openings 32, respectively. In the upper region of the fuel cell exhaust gas outlet region 34, the outlet openings 32 are positioned such that a fuel cell exhaust gas flow direction S B corresponds substantially to the ambient air flow direction Su of the heated ambient air U E. This means that these two flow directions S U, S B or the main flow directions of the two gas streams are substantially parallel and unidirectional with respect to one another. In the central region of the fuel cell exhaust gas outlet region 34, the outlet openings 32 are arranged such that the fuel cell exhaust gas flow direction S B' is substantially opposite the ambient air flow direction Su, that is to say these two flow directions S U, S B' or the main flow directions of the two gas streams are substantially parallel to one another and are directed opposite one another. In the lower part of FIG. 1, it is illustrated that at such a fuel cell exhaust gas outlet opening 32, the fuel cell exhaust gas A B is discharged not as a substantially unidirectional exhaust gas jet, but in a fan-like or cone-like configuration. Here, too, the main flow direction corresponding substantially to a center line of a discharge fan or discharge cone can either be directed opposite to the ambient air flow direction Su or, as shown, directed in the same direction thereto, or can be angled in another manner, for example orthogonally, to the ambient air flow direction Su.Note that in the fuel cell off-gas discharge region 34, all the fuel cell off-gas discharge ports 32 may have any one of the three different configurations described above and illustrated in FIG. 1, or fuel cell off-gas discharge ports 32 of different configurations may be provided. It is also possible to orient the fuel cell exhaust gas outlet openings 32 or a part of them in such a way that discharge takes place transversely to the ambient air flow direction Su of the heated ambient air U E flowing around the fuel cell exhaust gas outlet region 34, in order also to assist the mixing of fuel cell exhaust gas A B and heated ambient air U E as a result. If a fuel cell exhaust gas outlet opening 32 for discharging fuel cell exhaust gas A B is configured in a fan-like or cone-like configuration, the fuel cell exhaust gas outlet region 34 can have, for example, only a single fuel cell exhaust gas outlet opening 32, via which the fuel cell exhaust gas A B is discharged with a main flow direction substantially orthogonally to the ambient air flow direction Su, such that the two gas streams penetrate one another.The mixing of fuel cell exhaust gas A B and heated ambient air U E can furthermore be assisted by a fuel cell exhaust gas / ambient air mixing arrangement 46 arranged downstream of the fuel cell exhaust gas outlet region 34. This can comprise one or more mixers 48, which can be designed, for example, with deflector blades that provide for turbulence or flow deflection and thereby bring about efficient mixing of the fuel cell exhaust gas A B with the heated ambient air U E.By mixing the fuel cell exhaust gas A B having a high relative humidity with the heated ambient air U E having a comparatively low relative humidity, the fuel cell exhaust gas / ambient air mixture G is provided with a relative humidity which is significantly lower than the relative humidity of the fuel cell exhaust gas A B and has a value of far below 100%. If the fuel cell exhaust gas / ambient air mixture G with its relative humidity clearly below a value of 100% exits from the aggregate space 36 at the opening regions 40 to the environment, this comes spontaneously into contact with the cold ambient air U during operation at a comparatively low ambient temperature. This leads to the temperature also decreasing spontaneously due to the mixing of the fuel cell exhaust gas / ambient air mixture G with the comparatively cold ambient air U. Since the relative humidity of the fuel cell exhaust gas / ambient air mixture G is significantly below 100% before this mixing with the ambient air U, there is the possibility that, when the temperature of the fuel cell exhaust gas / ambient air mixture G falls during the mixing with the cold ambient air U, the relative humidity exceeds the value of 100% and therefore mist formation as a result of condensing water occurs, practically not.In order to be able to set the thermal interaction of the non-heated ambient air U introduced into the heat exchanger 44 with the cooling medium in a defined manner, a flow throttle arrangement 50 can be assigned to the heat exchanger 44. This can comprise, for example, upstream of the heat exchanger 44, a plurality of lamellae which can be adjusted for changing the flow capacity. By pivoting the fins and thus changing the flow capacity of the flow throttle arrangement 42, the quantity of ambient air U flowing through the heat exchanger 44 is changed. If less ambient air U is introduced into the heat exchanger 44, the heat transported in the cooling medium is transferred to a smaller amount of air, which can have the consequence that the ambient air U E leaving the heat exchanger 44 heated has a higher temperature. Thus, by regulating the amount of air flowing through the heat exchanger 44, on the one hand, and thus the temperature of the heated ambient air U E leaving the heat exchanger 44, on the other hand, it is possible to react to changes in the relative air humidity of the fuel cell exhaust gas A B in order thus to be able to generate a fuel cell exhaust gas / ambient air mixture G with a minimum possible relative humidity in the assembly chamber 36.By introducing the fuel cell exhaust gas A B and the heated ambient air U E into the aggregate space 36, it can be ensured that even before contact with the non-heated or cold ambient air U, there is uniform mixing of heated ambient air U E and fuel cell exhaust gas A B. For this purpose, it is particularly advantageous if a distance a of the fuel cell exhaust gas outlet region 34 or of the fuel cell exhaust gas outlet openings 32 from the ambient air outlet region 42 is not greater than 50%, preferably not greater than 10%, of a distance A of the opening regions 40 from the ambient air outlet region 42, at which opening regions 40, for example in the region of an underbody of the vehicle 12 or in lateral regions or in the rear region of the vehicle, the fuel cell exhaust gas / ambient air mixture G exits into the environment and comes into contact with the cold ambient air U. For example, the distance a can be the distance which the fuel cell exhaust gas outlet opening 32 situated furthest away from the ambient air outlet region 42 has to the ambient air outlet region 42. The distance A can be, for example, the distance which the opening region 40 closest to the ambient air outlet region 42 has to the ambient air outlet region 42.In a further embodiment variant of the ambient air heating arrangement 38 illustrated in FIG. 2, the latter can have a plurality of heat exchangers 44 a, 44 b, 44 c, through which the ambient air U to be heated flows successively, that is to say in series. The heat exchangers 44 a, 44 b, 44 cmay be associated with different cooling circuits, which may be provided to cool different system areas independently of one another or to maintain them at defined temperature levels independently of one another in the vehicle 12. For example, the heat exchanger 44 apositioned furthest upstream, on which the ambient air U to be heated impinges first, can be a low-temperature heat exchanger, while the heat exchanger 44 bmay be a medium-temperature heat exchanger and the heat exchanger 44 cmay be a high-temperature heat exchanger, which is provided, for example, to remove heat from the fuel cell arrangement 14 or to keep it at a defined temperature level. This means that the temperature of the cooling media flowing through the heat exchangers 44 a, 44 b, 44 cis increased in the flow direction of the ambient air U to be heated. Downstream of the heat exchanger 44 chaving the highest cooling medium temperature, the fuel cell exhaust gas outlet region 34 is positioned for discharging the fuel cell exhaust gas A B into the heated ambient air U E flowing around the latter.FIG. 2 further illustrates that an ambient air blower 52 may be provided for assisting or generating the flow of the ambient air to be heated or the heated ambient air, respectively. In this way, in particular even when the vehicle 12 is stationary, a sufficient flow through the ambient air heating arrangement 38 and thus a sufficient amount of heated ambient air U E can be ensured. Above all, if the ambient air heating arrangement 38 is positioned, for example, on a bus or a train or a locomotive in such a way that the relative wind does not flow directly against it, the ambient air blower 52 is particularly advantageous for generating a sufficient ambient air flow.While in principle the ambient air blower 52 can also be arranged upstream of the ambient air heating arrangement 38, i.e. upstream of the or all heat exchangers thereof, the positioning directly downstream of the fuel cell exhaust gas outlet region 34 is particularly advantageous since the swirling of the heated ambient air U E generated by the ambient air blower 52, then assists the mixing with the fuel cell exhaust gas A B. This effect can also be achieved if, as indicated by dashed lines in FIG. 2, ambient air blower 52 is positioned downstream of ambient air heating arrangement 38 and upstream of fuel cell exhaust gas outlet region 34 in the flow direction of heated ambient air U E.In a further variant of a vehicle constructed according to the invention, the fuel cell exhaust gas outlet region 34 and the ambient air outlet region 42 can in principle be positioned on the vehicle 12 in such a way that they do not discharge the fuel cell exhaust gas A B or the heated ambient air U E into a volume region formed in the vehicle 12 and which is in principle open to the environment, such as the unit chamber 36, but instead discharge the two gas streams, for example directly adjacent to one another, substantially directly into the environment or the non-heated ambient air U, so that the two gas streams mix substantially only in the environment, that is to say outside the vehicle 12. In order to ensure a sufficient reduction in the relative humidity of the fuel cell exhaust gas, it is advantageous if the quantity of the discharged heated ambient air U E is significantly greater than the quantity of the discharged fuel cell exhaust gas A B. The delivery of the two gas streams in such a way that, for example, the stream of the fuel cell exhaust gas A B is delivered to the environment surrounded by a sheath stream of heated ambient air U E can, in such an embodiment, assist in a mixing of fuel cell exhaust gas A B and heated ambient air U E leading to a sufficient reduction in the relative humidity.FIG. 3 illustrates an embodiment of this type in which the ambient air heating arrangement 38 and the fuel cell exhaust gas outlet region 34 are positioned so close to one another or next to one another that the gas streams emitted by them are introduced substantially next to one another into the volume region indicated as a mixing zone M in FIG. 3. The streams of fuel cell exhaust gas A B and heated ambient air U E pass through one another in the region of the mixing zone M, as a result of which the fuel cell exhaust gas / ambient air mixture G is formed.As explained above, such a mixing zone M can be located outside the vehicle 12, but can also be located inside the vehicle 12, for example in a region corresponding to the aggregate space 36, in a volume bounded by a lateral surface of the vehicle.While in such a configuration the angled positioning of the ambient air heating unit 38 or of the fuel cell exhaust gas outlet region 34 to one another, which positioning can be seen in FIG. 3, is particularly advantageous for achieving the gas flows passing through one another, it is in principle also possible to arrange the ambient air heating unit 38 and the fuel cell exhaust gas outlet region 34 with respect to one another in such a way that the flow directions S B, Su are substantially parallel to one another. Above all, when in such a configuration the mixing zone M is located outside the vehicle 12, for example below the underbody thereof, the mixing of fuel cell exhaust gas A B and heated ambient air U E can be brought about or supported by the ambient air receiving the two gas streams, which ambient air has a relative speed with respect to the two gas streams, which relative speed leads to swirling when the vehicle 12 is moving.In a further alternative configuration, the ambient air heating arrangement 38 and the fuel cell exhaust gas outlet region 34 can be arranged with respect to one another in such a way that the fuel cell exhaust gas outlet region 34 is arranged upstream of the ambient air heating arrangement 38 or the ambient air outlet region 42 thereof with respect to the ambient air flow direction Su. The fuel cell exhaust gas A B can be guided in such a way that it flows around the ambient air heating arrangement 38, i.e. for example the heat exchanger 44, but is not heated therein. Downstream of the ambient air outlet region 42, the fuel cell exhaust gas A B and the heated ambient air U E. emerging at the ambient air outlet region 42 then mix.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2023 108 806

[0003]

Claims

Vehicle, comprising: - a fuel cell system (10) having a fuel cell arrangement (14) and a fuel cell exhaust gas (A B) from the fuel cell arrangement (14)-receiving fuel cell exhaust gas system (20), wherein the fuel cell exhaust gas system (20) has a fuel cell exhaust gas outlet region (34) for discharging fuel cell exhaust gas (A B) from the fuel cell exhaust gas system (20), - an ambient air heating arrangement (38) for heating ambient air (U) to be mixed with at least a part of the fuel cell exhaust gas (A B), wherein the ambient air heating arrangement (38) has an ambient air outlet region (42) for discharging ambient air (U E) heated in the ambient air heating arrangement (38), characterized in that: - the fuel cell exhaust gas outlet region (34) is positioned downstream of the ambient air outlet region (42) with respect to an ambient air flow direction (Us) of the heated ambient air (U E) discharged at the ambient air outlet region (42) from the ambient air heating arrangement (38), or - the fuel cell exhaust gas outlet region (34) is positioned upstream of the ambient air outlet region (42) with respect to the ambient air flow direction (Us) of the heated ambient air (U E) discharged at the ambient air outlet region (42) from the ambient air heating arrangement (38), and / or - the fuel cell exhaust gas outlet region (34) and the ambient air outlet region (42) are positioned in such a way that a stream of fuel cell exhaust gas (A B) emitted at the fuel cell exhaust gas outlet region (34) and a stream of heated ambient air (U E) emitted at the ambient air outlet region (42) at least partially penetrate one another.Vehicle according to Claim 1, characterized in that the ambient air heating arrangement (38) comprises at least one heat exchanger (44), through which the ambient air (U) to be heated and a cooling medium flowing in a cooling circuit can flow, for transferring heat contained in the cooling medium to the ambient air (U) to be heated.Vehicle according to Claim 2, characterized in that the ambient air heating arrangement (38) comprises a plurality of heat exchangers (44a, 44b, 44c) through which the ambient air (U) to be heated can flow in series, preferably wherein the fuel cell exhaust gas outlet region (34) is positioned downstream of a heat exchanger (44c) of the plurality of heat exchangers (44a, 44b, 44c) which is positioned furthest downstream with respect to a flow direction of the ambient air (U) to be heated.Vehicle according to one of Claims 1 - 3, characterized in that the ambient air heating arrangement (38) is assigned a flow throttle arrangement (50) for throttling the quantity of the ambient air (U) to be heated which flows through the ambient air heating arrangement (38).Vehicle according to one of Claims 1 - 4, characterized in that the fuel cell exhaust gas outlet region (34) has at least one fuel cell exhaust gas outlet opening (32).Vehicle according to Claim 4, characterized in that: - at least one, preferably each, fuel cell exhaust gas outlet opening (32) is designed for discharging fuel cell exhaust gas (A B) in a fuel cell exhaust gas flow direction (S B) substantially corresponding to the ambient air flow direction (Su), or / and - at least one, preferably each, fuel cell exhaust gas outlet opening (32) is designed for discharging fuel cell exhaust gas (A B) in a fuel cell exhaust gas flow direction (S B') substantially opposite the ambient air flow direction (S U) or / and - at least one, preferably each, fuel cell exhaust gas outlet opening (32) is designed for discharging fuel cell exhaust gas (A , Preferably, each fuel cell exhaust gas outlet opening (32) is designed for the discharge of a fuel cell exhaust gas stream expanded in a fan-like or cone-like manner.Vehicle according to one of Claims 1 - 6, characterized in that, with respect to the ambient air flow direction (Su), a mixing arrangement (46) with at least one ambient air / fuel cell exhaust gas mixer (48) is arranged downstream of the fuel cell exhaust gas outlet region (34).Vehicle according to one of Claims 1 - 7, characterized in that the ambient air outlet region (42) is arranged for discharging heated ambient air (U E) into an assembly space (36) of the vehicle (12) which is open to the environment via at least one opening region (40), and in that the fuel cell exhaust gas outlet region (34) is arranged for discharging fuel cell exhaust gas (A B) into the assembly space (36).Vehicle according to Claim 8, characterized in that a distance (a) of the fuel cell exhaust gas outlet region (34) from the ambient air outlet region (42) is less than 50%, preferably less than 10%, of a distance (A) of the at least one opening region (40) from the ambient air outlet region (42).Vehicle according to the preamble of claim 1 or one of claims 1 - 9, characterised in that an ambient air fan (52) for conveying ambient air (U) to be heated and / or heated ambient air (U E) is associated with the ambient air heating arrangement (38), and in that the ambient air fan (52) is arranged downstream of the ambient air heating arrangement (38) with respect to the ambient air flow direction (Us).Vehicle according to Claim 10, characterized in that the ambient air fan (52) is arranged downstream of the fuel cell exhaust gas outlet region (34) with respect to the ambient air flow direction (Us).Vehicle according to one of Claims 1 - 11, characterized in that the fuel cell exhaust gas system (20) comprises a fuel cell exhaust gas treatment arrangement (22), wherein the fuel cell exhaust gas treatment arrangement (22) comprises at least one of the following assemblies: - liquid separator (24), - catalyst (26), - silencer (28).Method for operating a fuel cell system in a vehicle, preferably a vehicle according to one of Claims 1 - 12, in which method a mixture (G) of ambient air (U) and fuel cell exhaust gas (A B) emitted at a fuel cell exhaust gas outlet region (34) of a fuel cell exhaust gas system (20) assigned to a fuel cell arrangement (14) of the fuel cell system is generated, wherein at least some of the ambient air (U) mixed with the fuel cell exhaust gas (A B) is heated before mixing with the fuel cell exhaust gas (A B).Method according to Claim 13, characterized in that the heated ambient air (U E) and the fuel cell exhaust gas (A B) are discharged into an assembly space (36) of the vehicle (12) which is open to the environment, and in that the mixture (G) of fuel cell exhaust gas (A B) and heated ambient air (U E) is formed substantially in the assembly space (36).Method according to Claim 13 or 14, characterized in that the heated ambient air (U E) to be mixed with the fuel cell exhaust gas (A B) is heated in at least one heat exchanger (44) by thermal interaction with a cooling medium flowing in a cooling circuit of the vehicle (12).Method according to Claim 15, characterized in that, in order to set a temperature of the ambient air (U) to be heated in the at least one heat exchanger, a mass flow of the ambient air (U) flowing through the at least one heat exchanger (44) and / or a mass flow of the cooling medium flowing through the at least one heat exchanger (44) is changed.

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