DE102008053800A1 - Exhaust tract for proton exchange membrane-fuel cell system in vehicle, has collector for collecting water that is conveyed based on pressure in pipe portion and collector, where pressure is based on operating condition of fuel cell system - Google Patents

Abstract

The tract (1) has a collector (3) e.g. cylindrical hollow body, for collecting liquid water (4) separated from exhaust gas, where the water is separated in a region of evacuation of the water from the collector via a pipe portion (2). The collector is connected with the pipe portion in the region of the evacuation of the water by a connecting pipe (16) e.g. riser pipe. The water is conveyed from the collector via the connecting pipe depending on pressure (p1, p2) in the pipe portion and the collector, where the pressure is dependent on an operating condition of a fuel cell system. An independent claim is also included for a method for delivering liquid water collected in an exhaust tract of a fuel cell system.

Description

The The invention relates to an exhaust gas system for a fuel cell system with a conduit part, through which the exhaust gas is derivable. Of Furthermore, the invention relates to a fuel cell system with a such exhaust system. In addition, the invention relates a method for discharging accumulated in an exhaust line of a fuel cell system Liquid water.

Fuel cell systems are used in many applications, especially mobile applications, such as in a vehicle for propulsion or other aggregates, used as energy source. Most widely used here are fuel cells with proton exchange membranes (PEM), where the anode of the fuel cell with hydrogen as fuel and supplies the cathode with oxygen or air as the oxidant becomes. Anode and cathode are protected by a proton permeable, electrically non-conductive membrane separated.

at the electrochemical reaction of hydrogen and oxygen On water, electrical energy is generated by electrodes is tapped at the anode and cathode. Several individual electric series connected fuel cells become a fuel cell stack summarized.

The Membrane can be humidified by both humidified hydrogen Oxygen or air, but also by the resulting in the cathode Product water from the oxygen-hydrogen reaction humidifies become. Is too much water in the fuel cell, especially in the cathode, so reduced by a disturbed gas transport the Power of the fuel cell. This from the electrochemical reaction resulting water gets along with excess Air from the cathode in the form of liquid water or Water vapor via a fuel cell exhaust gas line the fuel cell system discharged. This exhaust pipe is common assigned to an exhaust line. Here, the water vapor, for example in the warm-up phase or at low outside temperatures, in condense the exhaust pipe. The exhaust gases of the anode, which is a significant Have less water, are also through the exhaust system discharged from the fuel cell system.

Of the Outlet of water in liquid form from a fuel cell system is undesirable for a variety of reasons, especially in a fuel cell system in mobile applications, since it is more expensive here to catch the escaping water. For example, it is in the use of a fuel cell system in a vehicle unwanted that liquid Water gets on the road and there possibly at low Freezes temperatures and contributes to ice formation.

at A vehicle powered by pure hydrogen is produced as an oxidation product Water, both in liquid and in gaseous state is delivered to the environment. For example, the discharge of liquid water from the fuel cell system via the exhaust line then take place when the vehicle is parked on a slope is. Likewise, this can occur when the fuel cell system idle. Even if the vehicle accelerates it may accumulate to a gushing out of Liquid water come from the exhaust system. The resulting Problems have already been mentioned above.

From the DE 10 2005 029 536 A1 a fuel cell system is known in which the liquid water collected in an exhaust line is atomized, in this regard, ultrasonic sensors are used, which are arranged in the exhaust line.

It Object of the present invention, an exhaust line and a fuel cell system as well as a method for discharging of creating liquid water accumulated in the exhaust line, in which the surge-like discharge of liquid water in relatively large quantities can be prevented.

These Task is by an exhaust line, which the characteristics after Claim 1, a fuel cell system having the features according to claim 25, and a method comprising the features according to claim 26, solved.

One inventive exhaust gas line for a fuel cell system comprises a conduit part, through which the exhaust gas can be conducted or diverted is. The exhaust system also includes a collection container for collecting the separated from the exhaust gas liquid water, which in the area of the removal of liquid water is separated from the collecting container of the conduit part. The collecting tank is with the conduit part in this area the removal of the liquid water from the reservoir connected to at least one connecting line.

Depending on an operating condition of the fuel cell system dependent pressures in the conduit part and the collecting container, the liquid water is conveyed or discharged via the connecting line from the collecting container. It is thus characterized by a specific mechanical staltung the exhaust line in a simple yet highly functional way so that the surge-like outlet in specific operating conditions of the fuel cell system and thus also an exhaust line, can be prevented. In a very specific manner, the pressure conditions occurring in the various operating conditions in the line part on the one hand and the collecting container on the other hand cleverly exploited to the effect that the undesirable surge-like discharge of liquid water can be prevented, on the other hand, however, the liquid water can be automatically transported in the appropriate dosage.

Especially can thus be avoided that relatively much accumulated liquid water uncontrolled exits the exhaust line and thus especially at low Ambient temperatures leads to a black ice on roads.

Preferably the conduit part is passed through the collecting container. This allows a compact design in addition to a particularly suitable implementation for adjusting the pressure conditions.

Especially is the collection container as a cylindrical hollow body educated.

Prefers the collecting container and the line part form a resonator. In this connection, a multifunctional design can be made be ensured that on the one hand, the collection of liquid water and the discharge can be guaranteed, on the other hand that by this resonator also an undesirable noise can be reduced. Especially with a hollow cylindrical Design of the collecting container, which is a tubular Design allows, the line part of this Surrounding container be surrounded, whereby the resonator design be made particularly advantageous in terms of soundproofing can.

The Conduit part preferably comprises a collection container extending portion, wherein the connection of the collecting container with the section via the connecting line within the collection container is formed. Also in this regard can be a highly functional design in a compact and realize space-minimized way.

Preferably the conduit part has a collecting vessel extending in the Section on which outside of the area for removing the liquid water from the reservoir has a plurality of through holes. By this configuration, on the one hand, the pressure setting between the interior of the conduit part and the interior of the collecting container with regard to the automatic discharge of liquid water be improved without a surge generation and above In addition, the reliable and automatic derivation of the the exhaust gas separated liquid water into the sump be enabled. In addition, carries Such a design with holes also positive in that the noise emission is reduced. Also an improved Soundproofing can be guaranteed.

Especially It is preferable if the holes in this section of the line part with different geometries and / or different Dimensions and / or different bore angles formed are. A situation-specific optimized realization with regard to on the functionality for automatic and no-noise discharge the liquid water from the reservoir and In addition, an improved sound characteristic can thereby be set. Preferably, the conduit part is a in the collecting container extending section, and in the space between the sump and the Section are arranged a plurality of partitions. This allows the sound attenuation with such particular vertically oriented partitions particularly positively influenced become. In particular, it may be provided in this connection that the partitions in the longitudinal direction of the pipe part considered arranged at different distances from each other are. Here, too, can be situation-specific and demand-dependent a particularly suitable sound attenuation can be realized.

Especially it is preferable if the at least one connecting line between the conduit part and the collecting container as a riser is trained. This allows the functionality of the automatic Discharge of the collected liquid water in the collecting tank at self-adjusting specific pressure conditions particularly effective and efficient.

Preferably, the region of the removal of the liquid water from the collecting container is formed at an end of the collecting container which opens into the environment in the end region of the conduit part. Just this specific positioning makes it possible that the discharged liquid water can be discharged immediately into the environment and does not have to complete relatively long distances in the line part. An undesirable further accumulation in the conduit part of the discharged liquid water can be prevented. In addition, can be achieved by such a configuration in a preferred manner that the liquid water after discharge from the Collecting container is virtually automatically discharged into the environment, if the end of the line part in a preferred manner has a corresponding shape, which ensures the independent derivation from the tail.

Preferably the connection line has an angled piece of pipe which is essentially vertical with a first section extends and extends substantially horizontally with a second portion extends. Also by this specific shaping of the connecting line can the support will be positively supported and above In addition, the undesirable surge of liquid water be prevented.

Especially extends the horizontally oriented portion of the connecting line into the end piece of the pipe part. Even so can the discharge of discharged from the reservoir liquid water be positively supported in the environment.

Preferably is a flow resistance element inside the pipe part arranged for an exhaust gas flow. This is a special one preferred embodiment with regard to the adjustment of the pressure conditions inside the pipe part and inside the collecting tank, thereby particularly effective operating phase specific the on the one hand desirable and on the other undesirable Discharging liquid water from the sump can be achieved.

Especially is the flow resistance element in the flow direction of the exhaust gas arranged in front of the connecting line. The production The pressure conditions can thereby very accurately and also very site-specific.

Especially the flow resistance element is designed so that the exhaust gas flow is operationally dependent on the operating phase such that in the area of the removal of liquid water from the Collecting container operating phase dependent different pressure conditions between the conduit part interior and the collection container interior are adjustable so that the operating phase depends on the liquid water automatically the connecting line can be conveyed from the collecting container is.

Especially the flow resistance element is designed so that the exhaust gas flow in the load case of the fuel cell system so conductive is that in the area of the removal of liquid water from the sump in the conduit part in the flow direction after the flow resistance element, a small pressure can be generated, as this in the sump in the area the removal of the liquid water from the reservoir adjusts, and the removal of the liquid water from the Collecting then takes place or is released.

Preferably the flow resistance element is designed so that the exhaust gas flow in the idle case of the fuel cell system is so conductive, that in the area of the removal of the liquid water from the collecting container in the conduit part in the flow direction after the flow resistance element, a pressure can be generated which is substantially equal to the pressure which is in idle case in the collection container in the area of the removal of the liquid water from the sump adjusts and the removal of the liquid water from the reservoir is prevented.

Especially it proves to be preferable if the flow resistance element Having the exhaust flow through openings. The pressure ratio setting This will again positively favored.

It it can be provided that the flow resistance element is formed cone-shaped. In this context can the flow resistance element may be an object which, for example as a pointed, provided with holes or recesses cone is. Again, the openings with pitch angles and Bohrungswinkeln be formed differently, in which case dependent from the inner diameter of the pipe part and the positioning in the Collecting container a corresponding embodiment of the pitch angle and the bore angle can be made.

It can also be provided that the flow resistance element a rounded cone with holes and recesses which is then formed, for example, as part of an egg shape is. The flow resistance element can also be used as a wire mesh or be designed as a baffle. It is also possible that the flow resistance element as a fan or swirl wheel in particular as a fixed fan is trained.

Especially proves the line part opening into the environment End piece, in which at least one sieve-like element is arranged. By this additional element that can from the sump discharged and then discharged into the environment liquid water be atomized.

This sieve-like element may have different shapes and be realized for example as a flat plate. It can, however also be realized a curvature, which is both concave as well as convex can be realized.

Especially it proves to be preferable if this sieve-like elements frost protection or freeze-proof is formed. In this context can provided for avoiding Zufrierens this sieve-like element Be that from coatings, especially nano-coatings is trained. Likewise, it may be provided in this connection that this sieve-like element is temperaturbeaufschlagbar and is particularly heatable. This can, for example, a heating resistor be provided, which is attached to or in the element or is introduced. By such a heating resistor can sieve-like element are heated and the passing liquid water can be heated, which prevents freezing can be. Likewise, it may be provided that this sieve-like Element is composed of a plurality of sub-elements, which are again designed like a sieve. In a related Embodiment, it is possible that the individual sub-elements are realized with larger mesh sizes, where in this context then mesh sizes larger 4 mm can be provided. These subelements can then be arranged in a staggered arrangement to each other, which again a relatively fine mesh screen-like system can be realized.

Of the Exhaust line can also have several connecting lines between the Have collecting container and the conduit part, which all are the same or different design can have. In this connection can the connection lines different geometries and / or different Dimensions, for example, different diameters and / or different heights, have.

By the connection line and its specific arrangement can be found in the Resonator reservoir, the sump, located liquid water discharged in a multi-stage process atomizing become. The optimal functioning of the attached connection line and their Wasseraustragskapazität is preferably by the flow resistance element in the interior of the conduit part so positively supported that the exhaust air discharged so is that this in the resonator in the water intake of the Connecting line generates an overpressure and in the flow direction of the exhaust gas in the pipe part after this flow resistance element generates a negative pressure. In idle mode of the fuel cell system In this context, the same pressure conditions arise one, so that over the connecting line no water discharge he follows. Depend on the dynamic exhaust air flow at load requirements of the fuel cell system, in particular in full load operation, pressure differences on, in particular maximum Pressure differences in full load operation, which is due to physical Conditions a discharge of the liquid water from the reservoir over the connection line can be realized, which, however does not represent a surgey discharge.

One Fuel cell system according to the invention an exhaust gas line according to the invention or a advantageous embodiment thereof. The fuel cell system is designed in particular as a mobile fuel cell system and arranged in a vehicle. It preferably comprises a Fuel cell stack with a plurality of fuel cells, which are preferably realized as PEM fuel cells.

at the inventive method for discharging of accumulated in an exhaust line of a fuel cell system Liquid water is from an exhaust gas stream, which through a conduit part of the exhaust gas stream flows, separated Liquid water collected in a collection container and about one at one the collecting tank and the line part separating area for removing the liquid water formed from the collection container and the collection container discharged with the line part connecting line. The discharge of the collected liquid water over the connection line is dependent on itself of specific operating conditions of the fuel cell system specific adjusting pressure conditions in the collecting container on the one hand and the line part, on the other hand. Especially this will happen automatically. Through this approach can the surge-like discharge of accumulated liquid water be prevented in the collecting container, thereby advantageously It can also be prevented in specific operating phases a relatively large amount of liquid water leaks. This can also be an undesirable smoothness on the road at low ambient temperatures avoided or at least be significantly reduced.

One Embodiment of the invention will be described below schematic drawings explained in more detail. It demonstrate:

1 a schematic sectional view through an embodiment of an exhaust line according to the invention in a first phase of operation;

2 a schematic sectional view through an embodiment of an exhaust line according to the invention in a second phase of operation; and

3 a schematic sectional view through an embodiment of an exhaust system according to the invention in a third phase of operation.

In The figures are the same or functionally identical elements with the provided the same reference numerals.

In 1 is a schematic side elevational view of an exhaust system 1 shown, which is associated with a fuel cell system. The fuel cell system is a mobile fuel cell system disposed in a vehicle.

About the exhaust system 1 The exhaust gases generated by the fuel cell system in operation are derived in an exhaust gas flow I, and in particular discharged into the environment. As already mentioned above, in the electrochemical reaction between hydrogen and oxygen in the fuel cell system, water is produced which is contained in the exhaust gas flow I. In this context, liquid water is formed 4 , which from the exhaust stream I due to the ambient conditions in the exhaust system 1 is deposited. The exhaust system 1 comprises a tubular conduit part 2 and a collection container 3 , The collection container 3 is formed as a cylindrical hollow body, which is a section 5 of the line part 2 surrounds. The pipe part 2 thus extends through the sump 3 through, with an end piece 6 of the line part 2 is curved and is oriented with its curvature, for example, in the direction of a roadway down. In addition, the tail has 6 on the sump 3 side facing away from an opening from which the out of the sump 3 discharged liquid water 4 dosed can leak.

As shown in 1 becomes the separated from the exhaust stream I liquid water 4 in the collection container 3 collected, in this context, the section 5 partially a plurality of holes 8th having. The section 5 is thus formed almost perforated, where it is in one area 7 , which for the removal of the liquid water 4 from the collection container 3 is provided, no such holes 8th having. In this area 7 is the conduit part 2 , in particular the section 5 , from the collection container 3 almost separated. The wall of the section 5 forms in this area 7 a complete separation from the interior of the collection container 3 ,

Preferably, the holes have 8th different geometries and / or different dimensions and / or different bore angles. The pipe part 2 , in particular the section 5 , and the collection container 3 are dimensioned so that in the area guided into each other a gap 9 is formed, so that the entire system between the line part 2 and the collection container 3 forms a resonator, which is also designed to function soundproofing. To improve this soundproofing are additional partitions 10 . 11 . 12 and 13 in this space 9 formed, which in the embodiment completely from the outside of the section 5 to the inside of the collection container 3 extend. In addition, the partitions 10 to 13 in the longitudinal direction of the line part 2 and thus arranged in the x-direction with different distances, whereby the sound attenuation can be further improved.

The collection container 3 has a first end 14 and a second end 15 on. The area 7 is adjacent as shown in the embodiment and close to the end 15 or subsequently to the end 15 educated. At this area 7 is a connection line 16 arranged, which is designed as a climbing sleeve or riser or riser. This connection line 16 connects the collection container 3 with the line part 2 , in particular the section 5 , The connection line 16 includes a vertical section 17 and a subsequent horizontal section 18 , The horizontal section 18 extends into the tail 6 of the line part 2 , where the vast majority of the interconnector 16 within the collection container 3 is arranged.

The orientation of the horizontal part 18 in the tail 6 is arranged so that over the connecting line 16 from the collection container 3 discharged liquid water 4 directly into the tail 6 can shrink and by the curvature of the tail 6 almost automatically from this tail 6 can expire.

In addition, the exhaust system includes 1 a flow resistance element 19 which is inside the pipe part 2 and in particular in the interior of the section 5 is arranged. Preferably, the flow resistance element 19 in the direction of the flow of the exhaust stream I in the area 7 arranged there and in particular in front of the connecting line 16 , In the exemplary embodiment, the flow resistance element 19 Conically designed and has a plurality of continuous holes 20 on.

The collection container 3 is at its ends 14 and 15 closed.

In the embodiment according to 1 is just a connection line 16 Of course, however, there can also be a plurality of such connecting lines 16 be arranged, which may be the same design or even different in terms of geometry and / or dimensions and / or orientation. About this connection line 16 can in a mehrstufi The method is the liquid water 4 be discharged atomizing.

Due to the design of the exhaust system 1 , in particular the arrangement of the components of the section 5 of the collection container 3 , the connection line 16 and the flow resistance element 19 can be achieved that depending on specific operating conditions of the fuel cell system specific pressure conditions between the pressures p1 and p2 in the range 7 in the collection container 3 and in the section 5 of the line part 2 be generated, so that, depending on these pressure conditions, a phase-specific discharge of the liquid water 4 from the connection line 16 or just this is just prevented. Due to this conception, an undesirable discharge of liquid water 4 be prevented and beyond that also be ensured that the liquid water 4 not played out.

Preferably, the flow resistance element 19 in the section 5 positioned so that the exhaust stream I is derived or deflected so that this in the resonator in the water intake of the connecting line 16 generates an overpressure p1 and in the flow direction behind the flow resistance element 19 in the section 5 a negative pressure p2 is generated. This is in particular automatically in operating states in which the fuel cell system is operated in the load case, in particular at full load. Depending on the dynamic exhaust air flow I is just at full load, the fuel cell system, the maximum pressure difference, in which the pressure p1 is substantially greater than the pressure p2, whereby a maximum water discharge through the connecting line 16 can be achieved, which is not bubbly, however.

Like in the 1 is shown, is in the region of the opening of the tail 6 and thus at the collecting container 3 opposite end of a sieve-like element 21 arranged, with which it can be achieved that the outflowing liquid water 4 is discharged atomized. The shape of the screen is merely exemplary and symbolically represented, and may be plan, concave or convex. To avoid freezing of the element 21 This can consist of nano coatings. But it can also be provided that the element 21 is heated, in this respect, for example, a heating resistor can be installed, which ensures that the sieve-like element 21 and the effluent liquid water 4 to be heated. It is also possible to have a combination of several such elements 21 to be arranged, which can then each be formed with a larger mesh size, for example greater than 4 mm. By an offset arrangement of the plurality of elements 21 can in this context again a relatively close-meshed system for atomizing the discharged liquid water 4 be achieved.

As shown, the connection line 16 arranged so that the connection between the line part 2 and the collection container 3 within the nested area of these two parts 2 and 3 is realized.

In 2 an operating condition is shown in which the fuel cell system is idling. The exhaust gas flow I is formed in this phase of operation and implemented at a flow rate that a part II by the Strömungswiderstandslement 19 is distracted and another part through the holes 20 the flow resistance element 19 passes through. In this idle phase of the fuel cell system then sets a pressure ratio at which the pressures p1 and p2 are substantially equal. Due to this pressure ratio adjustment can be achieved in the idle case that a water discharge from the reservoir 3 over the connecting line 16 not taking place. Since the idling phase of the fuel cell system predominantly occurs when the vehicle is at a standstill, as shown in FIG 2 be achieved that just then no surge-like discharge of liquid water 4 takes place and thus a roadway is not wetted with relatively much water, which can be prevented even at relatively low temperatures that such a large amount of liquid water exits and freezes on the road.

In contrast, as shown in FIG 3 an operating state of the fuel cell system showing the full load operation is shown. In this operating phase, the exhaust gas flow I is almost completely as shown in FIG 3 deflected, and the partial flow III at the flow resistance element 19 distracted and steps over the holes 8th in the section 5 in the collection container 3 one. In the load case of the fuel cell system thus sets a pressure ratio at which the pressure p1 is substantially greater than the pressure p2. Due to these pressure conditions and the physical conditions thus becomes an automatic discharge of liquid water 4 from the collection container 3 over the connecting line 16 in the line part 2 reached. Since the full load operation usually occurs when the vehicle is moving and in particular when the vehicle is accelerating, it is precisely in these specific operating phases that a suitable discharge of the liquid water can take place 4 be possible, whereby in this context, a surge-like outlet is prevented and a discharge is carried out, which also here the road surface does not unnecessarily wet with large amount of liquid water.

It is thus adjusted operating phase-dependent automatically such a pressure ratio between the pressures p1 and p2, precisely in the operating phases in which a discharge of the liquid water 4 advantageous and also desired, metered is made possible, and that in the operating phases in which just no liquid water leaks or no gushing liquid water outlet is desired, this is also prevented.

The pressure difference between the pressures p1 and p2 and thus the operation of the connecting line 16 increases depending on the exhaust air flow I or as a function of the load requirement and thus the operating state of the fuel cell system.

Since the liquid level in the resonator and in particular in the collecting container 3 can be specifically reduced, the function of the resonator for sound attenuation is positively supported. Also, the derivative of the exhaust air flow I acts on the flow resistance element 19 positive for the noise behavior.

1

exhaust gas line

2

line part

3

Clippings

4

liquid water

5

section

6

tail

7

Area

8th

holes

9

gap

10 11, 12, 13

partitions

14 15

The End

16

connecting line

17

vertical section

18

horizontal section

19

Flow resistance element

20

holes

21

element

I

exhaust gas flow

P1, p2

pressures

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102005029536 A1 [0007]

Claims (26)

Exhaust line for a fuel cell system with a line part ( 2 ), through which the exhaust gas is conductive, characterized in that a collecting container ( 3 ) for collecting the separated from the exhaust gas liquid water ( 4 ) is provided, which in the area of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) of the line part ( 2 ) is separated, wherein the collecting container ( 3 ) with the line part ( 2 ) in the area of the removal of the liquid water ( 4 ) with at least one connecting line ( 16 ) and dependent on an operating state of the fuel cell system dependent pressures (p1, p2) in the line part ( 2 ) and the collecting container ( 3 ) the liquid water ( 4 ) via the connecting line ( 16 ) from the collecting container ( 3 ) is eligible. Exhaust line according to claim 1, characterized in that the line part ( 2 ) through the collecting container ( 3 ) is guided. Exhaust tract according to claim 1 or 2, characterized in that the collecting container ( 3 ) is a cylindrical hollow body. Exhaust tract according to one of the preceding claims, characterized in that the collecting container ( 3 ) and the line part ( 2 ) form a resonator. Exhaust line according to one of the preceding claims, characterized in that the line part ( 2 ) in the collecting container ( 3 ) extending portion ( 5 ), wherein the connection of the collecting container ( 3 ) with the section ( 5 ) via the connecting line ( 16 ) within the collecting container ( 3 ) is trained. Exhaust line according to one of the preceding claims, characterized in that the line part ( 2 ) in the collecting container ( 3 ) extending portion ( 5 ), which outside the range for the removal of the liquid water ( 4 ) from the collecting container ( 3 ) a plurality of continuous holes ( 8th ) having. Exhaust tract according to claim 6, characterized in that the holes ( 8th ) have different geometries and / or dimensions and / or bore angle. Exhaust line according to one of the preceding claims, characterized in that the line part ( 2 ) in the collecting container ( 3 ) extending portion ( 5 ), and in the space ( 9 ) between the collecting container ( 3 ) and the section ( 5 ) Partitions ( 10 . 11 . 12 . 13 ) are arranged. Exhaust line according to claim 8, characterized in that the partitions ( 10 . 11 . 12 . 13 ) in the longitudinal direction of the line part ( 2 ) are viewed with different distances to each other. Exhaust line according to one of the preceding claims, characterized in that the at least one connecting line ( 16 ) is arranged as a riser. Exhaust line according to one of the preceding claims, characterized in that the region of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) at the end opening into the environment ( 6 ) of the line part ( 2 ) facing the end of the collecting container ( 3 ) is trained. Exhaust line according to one of the preceding claims, characterized in that the connecting line ( 16 ) is an angled piece of pipe which is connected to a first section ( 17 ) extends substantially vertically and is connected to a second section ( 18 ) extends substantially horizontally. Exhaust tract according to claim 11 and 12, characterized in that the horizontally oriented portion ( 18 ) into the tail ( 6 ) of the line part ( 2 ). Exhaust line according to one of the preceding claims, characterized in that in the interior of the line part ( 2 ) a flow resistance element ( 19 ) is arranged for the exhaust gas stream (I). Exhaust tract according to claim 14, characterized in that the flow resistance element ( 19 ) in the flow direction of the exhaust gas in front of the connecting line ( 16 ) is arranged. Exhaust tract according to claim 14 or 15, characterized in that the flow resistance element ( 19 ) is designed such that the exhaust gas flow (I) is operable depending on the operating phase such that in the region ( 7 ) of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) operating phase-dependent different pressure conditions between the conduit part interior and the collection container interior are adjustable so that operating phase dependent the liquid water ( 4 ) automatically via the connection line ( 16 ) from the collecting container ( 3 ) is eligible. Exhaust line according to claim 16, characterized in that the flow resistance element ( 19 ) is designed so that the exhaust gas flow (I) is conductive in the load case of the fuel cell system, that in the area ( 7 ) of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) in the line part ( 2 ) in the flow direction after the flow resistance element ( 19 ) is a smaller pressure (p2) can be generated, as this in the collecting container ( 3 ) in the area of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) and the removal of the liquid water ( 4 ) from the collecting container ( 3 ) he follows. Exhaust line according to claim 16 or 17, characterized in that the flow resistance element ( 19 ) is designed so that the exhaust gas flow (I) in the idle case of the fuel cell system is so conductive that in the area ( 7 ) of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) in the line part ( 2 ) in the flow direction after the flow resistance element ( 19 ) a pressure (p2) can be generated which essentially corresponds to the pressure (p1) which, in the case of idling, in the collecting container (p1) 3 ) in the area of the removal of the liquid water ( 4 ) from the collecting container ( 3 ) and the removal of the liquid water ( 4 ) from the collecting container ( 3 ) is prevented. Exhaust line according to one of claims 14 to 18, characterized in that the flow resistance element ( 19 ) the exhaust gas stream (I) through openings ( 20 ) having. Exhaust line according to one of claims 14 to 19, characterized in that the flow resistance element ( 19 ) is cone-shaped. Exhaust line according to one of claims 14 to 20, characterized in that the flow resistance element ( 19 ) is designed as a wire mesh. Exhaust line according to one of claims 14 to 20, characterized in that the flow resistance element ( 19 ) is designed as a fixed fan. Exhaust line according to one of the preceding claims, characterized in that the line part ( 2 ) an opening into the environment ( 6 ), in which at least one sieve-like element ( 21 ) is arranged. Exhaust tract according to claim 23, characterized in that the sieve-like element ( 21 ) Einfrierschutzsicher trained. Fuel cell system with an exhaust line ( 1 ) according to any one of the preceding claims. Method for discharging in an exhaust line ( 1 ) of a fuel cell system accumulated liquid water ( 4 ), in which the from an exhaust gas stream, which through a line part ( 2 ) of the exhaust gas stream, separated liquid water ( 4 ) in a collecting container ( 3 ) is collected and via a to a collecting container ( 3 ) and the line part ( 2 ) separating area ( 7 ) for the removal of the liquid water ( 4 ) from the collecting container ( 3 ) and the collecting container ( 3 ) with the line part ( 2 ) connecting connecting line ( 16 ), wherein the discharge of the collected liquid water ( 4 ) via the connecting line ( 16 ) depending on specific due to specific operating conditions of the fuel cell system specifically adjusting pressure ratios (p1, p2) in the collecting container ( 3 ) and the line part ( 2 ) he follows.