WO2014060100A1

WO2014060100A1 - Rotary disk valve for a fuel cell system

Info

Publication number: WO2014060100A1
Application number: PCT/EP2013/003115
Authority: WO
Inventors: Steffen Dehn; Ralf HÖβ; Christoph Koch
Original assignee: Daimler Ag
Priority date: 2012-10-19
Filing date: 2013-10-16
Publication date: 2014-04-24
Also published as: DE102012020648A1

Abstract

The invention relates to a rotary disk valve (14) with a valve housing (19) which has three line openings (20, 21, 22) and a rotary slide (23). The rotary slide (23) has at least one control edge (24) which interacts with the cross section of at least one of the line openings (20, 21, 22) in order to influence a flow of media through said line opening. The invention is characterized in that the rotary slide (14) is designed to be able to close one of the line openings (21) while simultaneously influencing the permeable cross section of the adjacent line opening (22). The rotary disk valve (14) can be used in particular in a fuel cell system (1) which is preferably arranged in a vehicle (2). The invention further relates to a method for starting such a fuel cell system (1).

Description

ROTARY DISC VALVE FOR A FUEL CELL SYSTEM

The invention also relates to a fuel cell system according to the further defined in the preamble of claim 3. The invention also relates to a vehicle with such a fuel cell system and a method for starting such a Fuel cell system, in particular in a vehicle, according to the closer defined in the preamble of claim 10.

Rotary slide valves are known per se from the prior art. They can be used, for example, to control a valve housing with three conduit openings for the inflow and outflow of media via a rotary valve or control edges of the rotary valve so that the control edges for influencing a

Media flow through the pipe openings with their cross section

interact. As an example, reference should be made to German Patent DE 198 34 577 B4 with regard to a rotary slide valve.

Fuel cell systems, in particular fuel cell systems for vehicles, are also known from the general state of the art. Now it is so that in particular the start of a fuel cell system, not only in a vehicle, but especially there, is very time-critical. It is crucial that the fuel cell is heated to operating temperature as quickly as possible so that the

Fuel cell system with the desired performance can work reliably and efficiently. For this purpose, it is known from the general state of the art and described for example in JP 2004 281201 A, that a cooling circuit of a fuel cell system having a radiator and a bypass arranged in parallel, wherein the flow through the radiator and the bypass via a Valve device is controllable. This one is able to start in the event of

Fuel cell system to bypass the radiator altogether, so as a fast

Heating of the cooling medium and the fuel cell itself to ensure without waste heat, which is needed in this case for heating, is discharged through the radiator to the environment. Later, in regular operation, the cooling medium flows through all or part of the cooling medium to the waste heat of the fuel cell to the

Environment, for example, one equipped with the fuel cell system

Vehicle, dissipate. The bypass can also be used to influence the cooling of the cooling medium, so that thereby, as well as alternatively or additionally by controlling the speed of a coolant conveyor, a targeted influencing the cooling of the fuel cell is possible.

Now it is especially when used in vehicles, but possibly also in stationary fuel cell systems so that in addition to the actual cooling circuit of the fuel cell system an additional secondary circuit branches off from the cooling circuit, which when used in a vehicle in particular as a heating circuit for the

Interior of the vehicle is formed. In this case, such a secondary circuit typically branches off between the fuel cell and the branch of the bypass around the radiator and has a smaller line cross-section than the actual one

Cooling circuit on. Due to this reduced line cross-section, higher pressure losses occur in the area of the secondary circuit, so that this only with one

comparatively small amount of cooling medium, in comparison to the amount of media flowing in the main cooling circuit, is flowed through. This is typically desirable, for example, when using the auxiliary cooling circuit as a heating circuit for the interior of a vehicle, since only a small part of the waste heat of the

Fuel cell system to be registered in the interior of the vehicle. However, in the starting case at cold ambient temperatures, it is now so that this only a very slow heating, for example, a vehicle interior by the

Subcooling circuit is enabled. This represents a loss of comfort for the users of the vehicle and is highly undesirable for them. For the use of the vehicle, this therefore means a disadvantage.

The object of the present invention is now to provide a rotary valve or a fuel cell system or a vehicle and a method for starting such a fuel cell system, which avoids these disadvantages. According to the invention this object is achieved by a rotary valve with the features in the characterizing part of claim 1. Advantageous developments emerge from the dependent claim. Furthermore, a fuel cell system with the features in the characterizing part of claim 3 solves the problem. Advantageous developments of the fuel cell system according to the invention will become apparent from the dependent claims. The object is also achieved by a vehicle having the features in claim 8. An advantageous development of the vehicle is specified in the dependent claim dependent therefrom. The object is ultimately also solved by a method for starting a fuel cell system with the features in the characterizing part of claim 10.

The rotary valve according to the invention provides that the rotary valve is designed so that it can close one of the conduit openings and simultaneously influence the adjacent conduit opening in its flow-through cross-section. In this way, the possibility is created that in addition to the pure continuous switching between the individual pipe openings and influencing one of the pipe openings is achieved in terms of their flow-through cross-section with simultaneously held adjacent adjacent pipe opening. This makes it possible to influence a targeted flow and can be throttled, for example, to improve the flow through other parallel connected components, even if they have a higher pressure drop than the main line in which the rotary valve is arranged.

In an advantageous embodiment of the rotary valve according to the invention, it is provided that the influence of the flow-through cross-section of the adjacent conduit opening from about 1/3 open to fully open ranges. A complete closing of two adjacent pipe openings is actually not desired in a rotary valve with three pipe openings, since it should only be used to divide the volume flows and not as a shut-off valve. It is therefore sufficient and allows a very simple structural design, if the rotary valve itself is designed so that it completely closes the one conduit opening and is additionally able to partially close the other conduit opening, for example, to throttle the flow through them , The fuel cell system according to the invention now provides that as a valve device, which affects the flow through a radiator and a bypass around the radiator, comparable to the known prior art, as

Rotary slide valve is designed according to the invention. Such a rotary valve is particularly easy to use and can very efficiently between a

Switch through the flow of the radiator on the one hand and a flow through the bypass on the other hand. The fact that in the rotary valve valve according to the invention at the same time to a closed opening influencing the adjacent opening is possible, it can also be used to throttle a directed in the desired direction flow in addition to, for example by a

Damming the volume in the cooling circuit a change in the cooling or

To allow flow through upstream in the flow direction of the coolant components.

In a very favorable development thereof, it is provided that branches from the cooling circuit in the flow direction of the cooling medium between the fuel cell and the bypass a secondary circuit with a smaller flow cross section than the cooling circuit, which opens again between the bypass and the fuel cell in the cooling circuit. Such a secondary circuit with higher pressure losses is in regular operation of a relatively small amount of cooling medium

flows through. This may well be desired and just as desired. Now it may be necessary or desirable in special situations that the secondary circuit is flowed through by a larger amount of cooling medium. About the invention

Rotary slide valve in this situation, for example, when the cooling medium is passed through the rotary valve in the bypass around the radiator, a throttling of the flow through the bypass, as in addition to the closed conduit opening, which leads to the radiator, by the inventively embodied rotary valve a throttling Line opening to the bypass is possible. About such

Throttling is built up a higher back pressure, so despite the lower

Flow cross-section of the secondary circuit of this with a higher amount of

Coolant is flowed through, which, for example, in a particularly favorable

Embodiment of the fuel cell system according to the invention for heating a medium and / or the environment of a heat exchanger in the secondary circuit can be used. According to a further very advantageous embodiment of the invention

Fuel cell system, it may also be provided that a device for detecting a heat demand in the region of such a heat exchanger is arranged so that the control of the rotary valve according to the invention can be made as needed.

The vehicle equipped according to the invention now uses exactly such a vehicle

Fuel cell system for providing its electrical drive power. It may be provided according to an advantageous embodiment of the vehicle according to the invention, that the secondary circuit is designed as a heating circuit for the interior of the vehicle. About the rotary valve according to the invention in the

Fuel cell system can thus be achieved within the vehicle, for example at a start of the vehicle and a correspondingly high heating power requirements in the interior of the vehicle by throttling the coolant flow through the bypass increased flow through the heating circuit as a secondary circuit, whereby the heating of the interior improves and comfort is increased for the occupants of such a vehicle.

The method according to the invention for starting a fuel cell system, in particular in a vehicle, uses the bypass, as known from the prior art, during the start of the fuel cell system in order to bypass the radiator and to prevent a strong cooling of the cooling medium. At the same time, the flow in the bypass can be throttled via the rotary valve in the embodiment of the invention. This results in an increased flow through the secondary circuit, so in particular the heating circuit for the interior of the vehicle, in the case of a vehicle application, so that in parallel to a rapid heating of the fuel cell system, the interior of the vehicle can be heated much faster and better than in the Embodiments according to the prior art is the case. Thus, an improvement in the comfort for the occupants of the vehicle can be achieved.

Further advantageous embodiments of the fuel cell system according to the invention and of the vehicle, of the method and of the rotary slide valve result from the remaining dependent claims and become clear from the exemplary embodiment, which is described in more detail below with reference to the figures. Showing:

Fig. 1 is a principle indicated vehicle with a section of a

The fuel cell system;

FIG. 2 shows a cooling circuit in a fuel cell system according to the invention in one possible embodiment; FIG.

Fig. 3 shows an inventive rotary valve in a first position of

Rotary valve;

4 shows an inventive rotary valve in a second position of

Rotary valve; and

5 shows a rotary valve according to the invention in a third position of the

Rotary valve.

In the illustration of Figure 1, a section of a fuel cell system 1 in an indicated vehicle 2 can be seen. The excerpt from the

Fuel cell system 1 is very highly schematic and simplified. It essentially comprises the fuel cell 3, which has an anode space 4 and a cathode space 5. The fuel cell 3 should be designed as a stack of individual cells, as a so-called fuel cell stack. The individual cells should be realized in PEM technology, so that a proton exchange membrane is arranged between the anode space 4 and the cathode space 5 of each individual cell. In the

Fuel cell 3 is made of oxygen and hydrogen electric power, for

Driving the vehicle 2, and produce product water as a waste product. the

Cathode space 5 is supplied to air as an oxygen supplier via an air conveyor 6. The exhaust air reaches in the very simplified here shown

Embodiment of the fuel cell system 1 directly to the environment. In addition, other known components such as intercoolers, humidifiers, catalytic burners, turbines and the like could be provided. All this is known from the prior art and of minor importance for the present invention, so that the illustration has been omitted.

Hydrogen from a compressed gas reservoir 7 via a pressure regulating and metering device 8 is supplied to the anode compartment 4 of the fuel cell 3. Exhaust gas from the anode compartment 4 also reaches the environment in the exemplary embodiment shown here. Here, too, the afterburning, for example, in a catalytic burner or the recirculation of the exhaust gas in a so-called Anodenloop or a Anode circuit generally known and common. Since this is also of secondary importance for the present invention, this was also omitted in the illustration of FIG.

In addition to the desired electrical power and the product water as a waste product also generates in the fuel cell 3 waste heat, which must be dissipated in the regular operation of the fuel cell 3. For this purpose, a cooling heat exchanger 9 in the illustration of Figure 1 is indicated within the fuel cell 3. This

Cooling heat exchanger 9 is connected to a dash-dotted line in the illustration of Figure 1 indicated cooling circuit 10 of the fuel cell system 1 in combination.

In the illustration of Figure 2, this cooling circuit 10, which is for the present invention is of crucial importance, again shown in detail. The cooling circuit 10 in the illustration of Figure 2 comprises of the components shown in Figure 1, only the cooling heat exchanger 9 within the fuel cell 3, which is symbolically indicated here again. In the cooling circuit 10 circulates a cooling medium, which for the removal of the waste heat of the fuel cell 3 via the

Cooling heat exchanger 9 flows in regular operation via a radiator 11, via which the waste heat is discharged to the environment of the vehicle 2. The flow of the cooling medium thereby maintains a coolant delivery device or coolant pump 12. The cooling circuit 10 also has a bypass 13 with a

Rotary slide valve 14 at the branch of the bypass 13, on the functionality will be discussed in more detail later. In addition to these components of the cooling circuit 10, a second secondary circuit 15 exists, which branches off in the flow direction of the cooling medium from the cooling circuit 10 between the cooling heat diver 9 of the fuel cell 3 and the rotary valve 14. This secondary circuit 15 is doing a

Heating circuit 15 for the interior of the vehicle 2 via a valve device 16, the heating circuit can be released or shut off. In the flow direction after the valve device 16 is then followed by an electric heater 17, which if necessary, when the waste heat from the fuel cell 9 not for heating the interior of the

Vehicle 2 is sufficient, an additional heating of the cooling medium in the

Heating circuit 15 can make. This is followed by a heat exchanger 18 as

Interior heat exchanger, before the cooling medium flowing in the heating circuit 15 passes back into the cooling circuit 10 and flows there together with the cooling medium from the cooling circuit 0 to the coolant pump 12. The flow-through cross section the heating circuit 15 is deliberately much smaller than the durchströmbare

Cross-section of the cooling circuit 10 is formed so as to ensure in regular operation that only a small amount of cooling medium flows through the heating circuit 15, as this is typically sufficient to heat the interior of the vehicle 2 in normal operation.

Now, when the fuel cell system 1 is started to accelerate the heating of the fuel cell 3, the cooling medium is merely circulated between the fuel cell 3 or its cooling heat exchanger 9 and the coolant delivery device 12 without cooling the cooling medium in the radiator 11. As a result, a heat loss, which would be highly undesirable in the starting phase of the fuel cell system 1, avoided. To make this possible, the already mentioned bypass 13 is arranged parallel to the radiator 11. Via the rotary valve 14, the flow with the cooling medium can then be adjusted so that only the bypass 13 is flowed through, if necessary, so that a cooling of the cooling medium in the radiator 11 is omitted. If subsequently the removal of waste heat to the surroundings of the vehicle 1 is desired in regular operation, then a flow through the radiator 11 and a simultaneous blockade of the bypass 13 can be achieved via the rotary valve 14.

In the illustration of Figure 3 is now a possible embodiment of the

Rotary slide valve 14 to recognize in a basic sectional view. A valve housing 19 of the rotary slide valve has three conduit openings 20, 21, 22, wherein the conduit opening 20 is in communication with the line coming from the cooling heat exchanger 9 of the fuel cell 3 and the conduit opening 21 with the line leading to the radiator 11. The conduit opening 22 communicates with the bypass 13 in

Connection. Via a rotary valve 23 with at least one control edge 24 can now be switched between the individual line openings 20, 21, 22. The flow shown in Figure 3 is the flow in the regular operation of the

Fuel cell system 1, so that the cooling medium flows completely from the cooling heat exchanger 9 of the fuel cell 3 to the radiator 1 1. The bypass 13 or the conduit opening 22, which is in communication with the bypass 13, is blocked by the rotary valve 23. In the analogous representation of Figure 4, however, the above-described starting case of the fuel cell system 1 is shown, in which the rotary valve 23, the conduit opening 21 and thus the flow through the radiator 11th blocked and the entire cooling medium flow through the conduit opening 22 and the associated bypass 13, bypassing the radiator 1 1, passes.

The problem now is that in the start of the fuel cell system, only a very small amount of cooling medium flows through the heating circuit 15, even if the valve device 16 is completely open. Since this amount, which is sufficient in normal operation for heating the interior, in the start of the

Fuel cell system 1 itself is still relatively cold, the heating of the interior of the vehicle 2 is thereby massively delayed. To counteract this problem is given by the special design of the rotary valve 14, as shown here, now the possibility that the cooperating with the conduit opening 22 control edge 24 of the rotary valve 23 is used as a throttle. Due to the higher pressure loss when flowing through the rotary slide valve 14 in the direction of the bypass 13, the ratio of the pressure losses between the cooling circuit 10 and the heating circuit 15 is changed so that a larger amount of cooling medium flows through the heating circuit. The desired warming of the interior of the

Vehicle 2 can thus be significantly improved and accelerated over the prior art. A thoroughly desired warming in this situation

Cooling medium via the heater 17 can also be improved if necessary. For this purpose, no separate component is necessary, but the rotary valve 14 can take over the task easily and efficiently by the appropriate use and a configuration of the rotary valve 23 so that this use is possible. Additional components, connection elements, interfaces within the cooling circuit 10 and the like can be saved. The structure is thus very simple, efficient and inexpensive to implement.

To really only cause the pressure loss through the control edge 24 in the conduit opening 22 and the bypass 13 is in the region of the interior of the

Vehicle 2, in particular in the region of the heat exchanger 18, arranged in the representation of Figure 2 in principle indicated means 25 for detecting a heating demand in or through the heating circuit 15. This may have, for example, temperature sensors and may additionally evaluate a driver's request, for example based on the setting of an air conditioning and heating device of the vehicle 2, so as to determine whether to heat or not. Only in the case that there is a heat demand, so should be heated, then the mentioned throttling done so that the pressure losses due to throttling occur only when they are really necessary.

Claims

claims

1. rotary valve (14) with a valve housing (19), which three

Conduit openings (20, 21, 22) and a rotary valve (23), wherein the rotary valve (23) has at least one control edge (24), which for

Influencing a media flow through at least one of

Conduit openings (20, 21, 22) cooperates with the cross-section,

characterized in that

the rotary valve (14) is designed so that it can close one of the conduit openings (21) and simultaneously influence the adjacent conduit opening (22) in its flow-through cross-section.

2. rotary valve (14) according to claim 1,

characterized in that

the influence of the flow-through cross-section of the adjacent

Line opening (22) from about 1/3 open to fully open ranges.

3. Fuel cell system (1) with a cooling circuit (10), which has a radiator (11) and a bypass arranged parallel thereto (13), wherein the

Flow through the radiator (11) and the bypass (13) via a valve device (14) is controllable,

characterized in that

the valve device is designed as a rotary slide valve (14) according to claim 1 or 2.

4. Fuel cell system (1) according to claim 3,

characterized in that

of the cooling circuit (10) in the flow direction of the cooling medium between the fuel cell (3) and the bypass (13) branches off a secondary circuit (15) with a smaller flow cross-section than the cooling circuit (10), which between the bypass (13) and the fuel cell ( 3) opens again into the cooling circuit (10).

5. Fuel cell system (1) according to claim 4,

characterized in that

the flow through the secondary circuit (15) via a valve device (16) is controllable.

6. Fuel cell system (1) according to one of claims 4 or 5,

characterized in that

the secondary circuit (15) has a heat exchanger (18) for heating a medium and / or the environment of the heat exchanger (18).

7. Fuel cell system (1) according to claim 6,

characterized in that

a device (25) for detecting a heat demand in the region of

Heat exchanger (18) is arranged.

8. Vehicle (2) with a fuel cell system (1) according to one of claims 3 to 7 for the provision of electrical drive power.

9. vehicle (2) according to claim 8,

characterized in that

the secondary circuit is designed as a heating circuit (15) for an interior of the vehicle (2).

10. A method for starting a fuel cell system (1) according to one of

Claims 3 to 7, in particular in a vehicle (2) according to claim 8 or 9, wherein during the start of the fuel cell system (1), the cooling medium in the cooling circuit (10) in the bypass (13) is guided around the radiator (11),

characterized in that

at a heat demand in the secondary circuit (15) via the rotary valve (14), the flow through the bypass (13) is throttled.