• 专利附录
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  • 权利要求
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    • 专利摘要:
    The invention relates to a measuring method for determining the recirculation rate (RR) in the anode gas circuit (50) of a fuel cell system (1) having at least one fuel cell (10), wherein an anode gas (52) from an anode chamber (13) of the fuel cell is connected to an anode gas recirculation line (51). 10) is supplied with a gas conveying device (70) and the anode gas (52) in a anode in the gas circulation line (51) arranged anode gas heat exchanger (60) is thermostated. For this purpose, the following method steps are carried out: measuring a first differential pressure loss (LIP1_2) along a first line section (101) of the anode gas recirculation line (51), which in the operating state of the fuel cell system (1) is traversed by a first mass flow (M1_2); - Measuring a second differential pressure loss (LlP3_4, LlP2_3) along a second line section (102, 103) of the anode gas recirculation line (51), which in the operating state by a different mass flow compared to the first mass flow (M1_2) second mass flow (M3_4, M2_3) is traversed; - Calculating the differential pressure loss ratio (RllP) by quotient of measured second differential pressure loss (LlP3_4; LlP2_3) to measured first differential pressure loss (LlP1_2); Determining the recirculation rate (RR) in the anode gas cycle (50) on the basis of a characteristic of the fuel cell system (1) system characteristic (S) as a function of the calculated differential pressure loss ratio (RllP).
    公开号:AT517685A4
    申请号:T735/2015
    申请日:2015-11-17
    公开日:2017-04-15
    发明作者:Ing Dr Martin Hauth Dipl
    申请人:Avl List Gmbh；
    IPC主号:
    专利说明:

    Measuring method and measuring device for determining the recirculation rate
    The invention relates to a measuring method for determining the recirculation rate in the anode gas cycle of a fuel cell system, which fuel cell system comprises at least one fuel cell with at least one arranged in a cathode compartment cathode, at least one arranged in an anode compartment anode and an existing between the cathode compartment and anode compartment electrolyte, wherein with a Anodengasrezirkulationsleitung anode gas from the anode compartment of the at least one fuel cell is supplied with at least one gas conveyor and the anode gas is thermostated in at least one arranged in the Anodengasrezirkulationsleitung anode gas heat exchanger. Furthermore, the invention relates to a measuring device for carrying out the measuring method according to the invention.
    A fuel cell system, which is used in particular as an auxiliary power supply device in motor vehicles or as a "stationary power plant", usually comprises at least one fuel cell for generating electric current from cathode air and reformate gas. Such a fuel cell is usually composed of a plurality of individual fuel cell elements, which are stacked on each other and are referred to as a fuel cell stack. For generating reformate gas, the fuel cell system may be equipped with a reformer which generates the reformate gas from a fuel, usually a hydrocarbon such as natural gas, as well as reformer air and / or water vapor. The reformate gas then contains hydrogen gas and carbon monoxide. The reforming can take place in a separate reformer or in the fuel cell itself. The fuel cell system can also be equipped with an air supply device which sucks in ambient air by means of an air conveyor from an environment of the fuel cell system and subdivides these, for example, into reformer air and cathode air. The reformer air can then be supplied to the reformer via a reformer air line, while the cathode air can be supplied via a cathode air line to a cathode side of the at least one fuel cell. Usually, in such a fuel cell system, it is provided to guide anode gas of an anode side of the at least one fuel cell in the direction of the reformer by means of a recirculation line so as to be able to recycle anode exhaust gas from the respective fuel cell to the reformer. For driving the anode exhaust gas, a gas delivery device for conveying hot anode exhaust gas is usually arranged in the recirculation line, wherein for this purpose usually a recirculation pump or a propulsion jet pump designated as an ejector are used. For optimum operation of such a fuel cell, it is necessary to obtain accurate information about the recirculation rate of the recirculated anode exhaust gas. This makes it possible to determine how much of the water required for the reforming processes is supplied via the recirculation and it can be prevented undesirable carbon formation, which occurs especially when a solid oxide fuel cell is used as a fuel cell and this is operated directly with methane gas. Furthermore, thereby increasing the utilization rate of the fuel is possible.
    According to the prior art, the determination of the recirculation rate is usually carried out with an additional pressure gauge with which the pressure in flowing media or fluids can be determined in accordance with the characteristics of the Bernoulli equations. By way of example, flow orifices, pitot tubes or Venturi nozzles of such per se known pressure gauges may be mentioned here. Such a pressure measuring device is arranged in the recirculation line in order to obtain information about the recirculation rate by means of the pressure difference occurring in the process. In most cases, a Venturi tube is used, whereby conclusions about the recirculation rate are possible by measuring the measurable pressure difference occurring across the Venturi tube according to the Bernoulli principle. The disadvantage of this, however, is that the additional pressure gauge or venturi introduces an additional considerable pressure loss into the recirculation line of the anode exhaust gas. This is particularly the case when one wants to cover a particularly large measuring range with a single pressure gauge: In order to enable a reliable measurement of the pressure gauge even at low mass flows, an at least small, measurable pressure difference must be achieved, the relatively small free flow cross sections in the Flow or in Venturi tube of the pressure gauge requires, however, lead at high mass flows to a considerable pressure loss in the recirculation line. Furthermore, it is disadvantageous that such an additional pressure gauge causes additional costs and increases the space requirement of the recirculation line, not least because of the usually longer inlet path, which is necessary for a reliable pressure difference measurement by Venturi tube as uniform as possible, directed flow of the pressure gauge in the To ensure recirculation line.
    Another significant disadvantage of using an additional pressure gauge such as a Venturi tube is that for a reliable determination of the recirculation rate in the anode circuit by interpretation of the pressure difference in addition a precise knowledge of the gas composition of the pressure gauge flowing through anode exhaust gas is necessary. Since the gas composition is difficult to determine during operation, an accurate determination of the recirculation rate is also difficult.
    It is therefore the object of the present invention to provide a reliable and simple measuring method for determining the recirculation rate in the anode circuit of a fuel cell, which avoids the described disadvantages of the prior art. It is a further object of the present invention to provide a corresponding measuring device for carrying out the measuring method according to the invention.
    According to the invention, the first object, namely to provide an improved measuring method, is achieved by a generic measuring method for determining the recirculation rate in the anode gas cycle of a fuel cell system in that the following method steps are followed:
    Measuring a first differential pressure loss along a first line section of the anode gas recirculation line, which first line section is traversed by a first mass flow in the operating state of the fuel cell system;
    Measuring a second differential pressure loss along a second line section of the anode gas recirculation line, which second
    Line section is traversed in the operating state of the fuel cell system of a different mass flow compared to the first mass flow second mass flow;
    Calculating the differential pressure loss ratio by quotient of the ratio of measured second differential pressure loss to measured first differential pressure loss; such as
    Determining the recirculation rate in the Anodengaskreislauf based on a characteristic of the fuel cell system system characteristic as a function of the calculated differential pressure loss ratio.
    Particularly preferred embodiments and further developments of the measuring method according to the invention and the measuring device according to the invention are the subject matter of the subclaims.
    According to the invention, the pressure conditions at different points of the anode gas recirculation line are used. It makes use of the fact that it comes with increasing power load requirements during operation of the fuel cell system to changes in the mass flow downstream of the anode. Owing to the current load requirement, oxygen ions pass from the cathode, which has an excess of oxygen, through a membrane which separates the cathode space from the anode space into the anode space, where they react with the hydrogen present there to form water vapor, which is then additionally present after the anode outlet and thus increases the mass flow in the anode gas recirculation line downstream of the anode compartment.
    On the one hand, a first differential pressure loss along a first line section of the anode gas recirculation line is now measured, wherein the first line section is traversed by a first mass flow during operation of the fuel cell system. For example, the measurement of the first differential pressure loss in the anode gas supply line, that is the input side of the anode compartment, as a two-point differential pressure measurement before and after the anode gas heat exchanger at its comparatively cold heat exchanger side.
    At substantially the same time, a second differential pressure loss along a second line section of the anode gas recirculation line is measured, this second line section is traversed by a second mass flow during operation of the fuel cell system, which is different in size, that is larger or smaller than the first mass flow in the first line section. For example, the measurement of the second differential pressure loss in the Anodengasableitung, ie the output side of the anode compartment, as a two-point differential pressure measurement in each case before and after the anode gas heat exchanger at the comparatively hot heat exchanger side.
    As the current load increases, for example, the anode output side mass flow becomes larger relative to the anode-side mass flow, since with increasing current load, the mass flow of oxygen which passes from the cathode through the electrolyte into the anode compartment and is transported in the anode gas outlet in addition to the anode gas flow increases. Likewise, the two differential pressure losses behave, which are determined for example via the heat exchanger.
    It has now surprisingly been found that regardless of the load requirement, a relationship between the differential pressure loss ratio, which as a quotient of the second differential pressure loss - determined, for example, at comparatively higher mass flow - the first differential pressure loss - at comparatively lower mass flow determined - and the recirculation rate. Thus, it is possible, based on the thus calculated or measured differential pressure loss ratio, the gas delivery device, for example, a recirculation pump to regulate so that in each case the desired recirculation rate in the anode gas cycle is adjustable.
    Until now, it was necessary for the determination of a complete map to record the relationship between the pressure drop via an additional pressure gauge and the respective associated mass flow for different power loads and correlated with the individual recirculation rates. During operation, with knowledge of the pressure drop at any point of the anode gas recirculation line and the current load, the recirculation pump could then be readjusted so that the desired
    Recirculation rate receives. In addition to the determination of the current load-dependent pressure increase on the additional pressure gauge and the temperature determination in the anode gas to additionally the respective gas composition of the anode gas had to be determined, which is quite possible in the context of a calibration, but for the determination of the recirculation rate in real operation extremely complicated and impractical is.
    The invention now allows rapid regulation of the recirculation rate without additional components in the anode gas recirculation line. One of the advantages of the method according to the invention is that due to the current load-independent relationship between the pressure difference and the recirculation rate, the calibration only has to be performed for a current load range.
    Advantageously, in a measuring method according to the invention, the system characteristic as a relationship between the differential pressure loss ratio and the recirculation rate may be substantially independent of a current load. In this variant of the measuring method according to the invention, the recirculation rate in the anode gas cycle is determined on the basis of a system characteristic characteristic of the fuel cell system, which is independent of the current load or which is assumed to be substantially independent of the current load. Thus, it is advantageous in the determination of the system characteristic curve no variation of the measurements at different power loads required. It is only necessary to determine a plurality of different pairs of values of differential pressure loss ratios and the correspondingly corresponding recirculation rates, which serve as interpolation points for determining the system characteristic characteristic of the respective fuel cell system.
    Suitably, in a measuring method according to the invention, the system characteristic may indicate a linear relationship between the differential pressure loss ratio and the recirculation rate. In this further variant of the measuring method, the relationship between the differential pressure loss ratio and the recirculation rate is assumed to be linear. The system characteristic is thus formed or described by a linear function. Advantageously, no variations of the measurements at different current loads are required to determine the linear system characteristic, and only two interpolation points of the linear system characteristic with different value pairings of differential pressure loss ratios and correspondingly corresponding recirculation rates have to be determined.
    In a measuring method according to the invention, the differential pressure loss ratio can particularly advantageously decrease along the system characteristic curve with increasing recirculation rate. In this variant of the measuring method, the system characteristic curve depicts an indirectly proportional ratio of the recirculation rate and the corresponding differential pressure loss ratio.
    Advantageously, in a measuring method according to the invention, the system characteristic curve can be calibrated in each case for a fuel cell system by determining the differential pressure loss ratios at different recirculation rates.
    In a preferred embodiment, in a measuring method according to the invention, the first differential pressure loss can be measured along a first line section in the anode gas supply line on the cold heat exchanger side of the at least one anode gas heat exchanger and the second differential pressure loss can be measured along a second line section in the anode gas outlet on the hot anode side of the same anode gas heat exchanger. Advantageously, in this embodiment, both differential pressure losses are measured at the cold or at the hot heat exchanger side of the same heat exchanger.
    In another embodiment, in a measuring method according to the invention, the first differential pressure loss in the anode gas supply on the cold heat exchanger side upstream and downstream of the at least one anode gas heat exchanger can be measured and the second differential pressure loss in the anode gas drain on the hot heat exchanger side respectively upstream and downstream of the same anode gas heat exchanger can be measured. Advantageously, in this embodiment, both differential pressure losses are respectively measured on the cold or on the hot heat exchanger side before and after the same heat exchanger. The resulting differential pressure loss ratio is thus determined on a single component - the heat exchanger in the anode gas recirculation line.
    In an alternative embodiment variant, in a measuring method according to the invention, the first differential pressure loss in the anode gas supply line on the cold heat exchanger side upstream and downstream of the at least one Anodengaswärmeübertragers be measured and the second differential pressure loss along a second line section of the anode gas recirculation line upstream and downstream of the anode space are measured. In this embodiment, the first differential pressure loss in the anode gas supply line before and after the heat exchanger is compared or set in relation to the second differential pressure loss before and after the anode space. Thus, in this embodiment, for determining the differential pressure loss ratio, pressure losses of the heat exchanger and the anode space of the fuel cell are set in proportion.
    In one development of the invention, in a measuring method, anode gas can be supplied to the reformer with the at least one gas conveying device.
    The further object of the present invention to provide a corresponding measuring device for carrying out the measuring method according to the invention is achieved by a measuring device comprising at least a first differential pressure loss measuring unit for determining a first differential pressure loss, which is positioned with two spaced pressure measuring points along a first line section of an anode gas recirculation line wherein in the operating state of the fuel cell system, the first line section is flowed through by a first mass flow, and the at least one second differential pressure loss measuring unit for determining a second differential pressure loss, which is positioned with two spaced pressure measuring points along a second line section of the anode gas recirculation line, wherein in the operating state of the fuel cell system second line section of a second Mas flows senstrom, which second mass flow is different from the first mass flow of the first line section, wherein the measuring device further comprises a computing unit, of which
    Computing unit a differential pressure loss ratio by quotient of the ratio of the measured second differential pressure loss to measured first differential pressure loss is calculated and the measuring device further comprises an evaluation of which evaluation based on the calculated differential pressure loss ratio and based on a characteristic of the fuel cell system system characteristic as a function of each calculated differential pressure loss ratio, the respective recirculation rate determined is which recirculation rate can be displayed by a display unit.
    In an advantageous embodiment of the measuring device according to the invention, the arithmetic unit, the evaluation unit and the display unit can be coupled to one another by signal lines. In this variant of the measuring device, the individual computing, evaluation and display units are each coupled to one another by signal lines. Advantageously, these units are also arranged together within a housing of the measuring device or integrated into such a housing. Thus, a measuring device is provided with which the respective recirculation rate of the anode gas cycle can be determined and also displayed.
    Suitably, in a measuring device according to the invention, the system characteristic curve can be calibrated in each case for a fuel cell system by determining the differential pressure loss ratios at different recirculation rates.
    Advantageously, in a measuring device according to the invention, the system characteristic curve may be selectable with a connection, independent of a current load, between the differential pressure loss ratio and the recirculation rate.
    In an alternative embodiment of the invention, in a measuring device, the system characteristic with a linear relationship between the differential pressure loss ratio and the recirculation rate can be selected.
    Further details, features and advantages of the invention will become apparent from the following explanation of exemplary embodiments schematically illustrated in the drawings. In the drawings: FIG. 1 shows in a process flow diagram a fuel cell system according to the prior art, wherein in an anode gas cycle an additional pressure gauge is provided for determining a characteristic pressure loss; 2 is a diagram of a conventional method for determining the recirculation rate in the prior art, wherein the characteristic pressure losses determined with the additional pressure gauge in the anode gas cycle are respectively plotted as a function of the current loads at different recirculation rates; 3 shows a detail of a process flow diagram of a fuel cell system according to the invention, wherein no additional pressure gauge is present in the anode gas cycle; 4 shows in a detail view of FIG. 3 a variant of a measuring method according to the invention with a measuring device according to the invention; 5 shows a diagram of the measuring method according to the invention for determining the recirculation rate in the anode gas cycle on the basis of a system characteristic characteristic of the fuel cell system as a function of the respectively calculated differential pressure loss ratio.
    1 shows a schematic process flow diagram of a fuel cell system 1 according to the prior art, wherein at least one fuel cell 11 with at least one arranged in a cathode compartment 11 cathode 12, with at least one disposed in an anode compartment 13 anode 14 and with a between the cathode compartment 11 and Anode space 13 existing electrolyte 15 are provided. In operation, oxygen 19, which is symbolized by an arrow 19, flows from the cathode through the electrolyte 15 into the anode compartment 13. To determine the recirculation rate, an additional pressure gauge 25, for example a venturi 25, is provided in the anode gas circuit 50. The anode gas cycle 50 comprises, in addition to the additional pressure gauge 25, that is installed in a recirculation line 51 of the anode gas 52, further a cycle section designated as anode gas feed line 53, wherein the
    Anodengaszuleitung 53 input side is oriented to the anode compartment 13 and designated as Anodengasableitung 54 cycle section, the output side of the anode compartment 13 leads away. The anode exhaust gas line 54 branches in the downstream anode gas direction 51 to the anode space 13 in an anode exhaust stream 55 and in an Anoderecyclegasstrom 56, the anode recycle 56 is recycled and mixed with fresh fuel 57 and this mixture in turn in the anode gas supply 53 to the anode compartment 13Jzugeführt.
    By way of example, FIG. 1 shows a fuel cell system 1 with a so-called solid oxide fuel cell 10 (SOFC). It is a high-temperature fuel cell operated at operating temperatures of about 650 ° to 1000 ° C. The electrolyte 15 of this cell type is made of a solid ceramic material capable of conducting oxygen ions but insulating for electrons. On both sides of the electrolyte layer 15, the electrodes, cathode 12 and anode 14 are mounted. They are gas-permeable electrical conductors. The oxygen ion-conducting electrolyte 15 is provided, for example, as a thin membrane in order to be able to transport the oxygen ions with low energy. It works only at the prevailing high temperatures. The electrolyte side facing away from the outer side of the cathode 12 is surrounded by air, the outer anode side 14 of fuel gas. Unused air and unused fuel gas and combustion products are extracted.
    Solid oxide fuel cells 10 are galvanic cells for continuous electrochemical power generation, which are usually operated as a fuel cell stack, so-called SOFC stacks, that is, as an interconnection of a plurality of fuel cells 10. For clarity, only a single fuel cell 10 is illustrated in FIG. SOFC fuel cell systems 1 also include corresponding heat exchangers, such as the anode gas heat exchanger 60 designated in FIG. 1, for preheating the anode gas 52 in the anode gas supply line 53, ie on the cold heat exchanger side 61, by heat exchange in countercurrent with the hot anode gas 52 in the anode gas discharge line 54 on the hot heat exchanger side 62 is used. Furthermore, such a fuel cell system 1 comprises a gas delivery device 70 in the Anodengaskreislauf 50, a reformer 80 and other components such as a DC-A / Wechselstrom inverter, a corresponding
    Control and other components that are necessary for the largely or completely automatic operation of the fuel cell system 1. The reformer 80 serves to produce a reformate gas from a fuel 57 or fuel, usually a hydrocarbon such as natural gas (English: natural gas, short: NG) and reformer air and / or water vapor. The reformate gas then contains hydrogen gas and carbon monoxide.
    The function of each galvanic cell and of each electrochemical reaction in general is based on a redox reaction in which reduction and oxidation occur spatially separated, namely at the interface between the electrode and the electrolyte. In the solid oxide fuel cell 10, this redox reaction is a reaction of oxygen with the fuel, which may be hydrogen, but here also includes carbon monoxide, for example. Excess oxygen prevails on the cathode side 12, whereas oxygen deficiency prevails on the anode side 14 because the oxygen present reacts with the hydrogen present, for example. By this concentration gradient, the oxygen 19 diffuses from the cathode 12 through the electrolyte 15 to the anode 14. The electrolyte 15 in between, however, is permeable only to oxygen ions. When the oxygen molecule reaches the interface between the cathode and the electrolyte, it absorbs two electrons, becoming an ion and penetrating the barrier. Arrived at the boundary to the anode 14, it reacts catalytically with the fuel gas with the release of heat and the corresponding combustion products, and again emits two electrons to the anode. A prerequisite for this is a current flow - the actual purpose of the solid oxide fuel cell - whereby the current flow can be used elsewhere.
    The chemical reactions taking place at the anode 14, the cathode 15 and the cumulative reaction via both electrodes of the fuel cell can therefore be noted as follows:
    Anode:
    Cathode:
    Total reaction:
    As already explained in detail above and illustrated in FIG. 2, to determine the recirculation rate in the anode gas circuit 50, it has hitherto been necessary to detect with the additional pressure gauge 25 in the anode gas circuit 50 certain characteristic pressure losses as a function of the different current loads at different recirculation rates RR. The characteristic pressure loss ΔΡι_2 was generated and measured, for example, by means of a Venturi tube 25, which is installed in the Anodengaskreislauf 50. The disadvantage is in addition to the additional pressure loss in the anode gas circuit 50 due to the additionally required pressure gauge 25 for determining the recirculation rate also the knowledge of the gas composition of the anode gas 52 is required. For this reason, the characteristics shown in FIG. 2, which at different recirculation rates of 70%, 80% and 90% respectively show the relationship between characteristic pressure loss ΔΡι_2 and current intensity, are additionally dependent on the temperature of the anode gas and its gas composition at the respective pressure measuring point , Thus, an extensive map for the entire operating range of the fuel cell system 1 must be determined for this conventional measuring principle, which is very complicated and also inaccurate.
    FIG. 3 shows a detail of a process flow diagram of a fuel cell system 1 according to the invention, wherein no additional pressure gauge is required in the anode gas circuit 50. The further components or assemblies required for operation of the fuel cell system 1 correspond, for example, to the list shown in FIG. The measurement of the differential pressure losses takes place in the Anodengaskreislauf 50 shown in FIG. 3, for example, according to the arrangement shown in Fig. 4.
    FIG. 4 shows in a detailed view of FIG. 3 a variant of an embodiment of a measuring method according to the invention with a measuring device 200 according to the invention. For this purpose, the recirculation rate RR in the anode gas circuit 50 of a fuel cell system 1 is determined by the measuring device 200 as follows:
    With a first differential pressure loss measuring unit 91, a first differential pressure loss ΔΡι_2 is determined, wherein the first differential pressure loss measuring unit 91 with two spaced apart
    Pressure measuring points Pi, P2 along a first line section 101 of the anode gas recirculation line 51 is positioned. This first line section 101 is traversed in the operating state of the fuel cell system 1 by a first mass flow Mi_2. The pressure measuring point Pi is arranged here in the anode gas supply line 53 upstream of the anode gas heat exchanger 60. The pressure measuring point P2 is arranged downstream of the anode gas heat exchanger 60 in the anode gas discharge line 54. The first differential pressure loss ΔΡι_2 is thus determined here along a first line section 101 on the cold heat exchanger side 61 via the anode gas heat exchanger 60.
    With a second differential pressure loss measuring unit 92, a second differential pressure loss ÄP3_4 is determined, wherein the second differential pressure loss measuring unit 92 with two spaced pressure measuring points P3, P4 along a second line section 102 of the anode gas recirculation line 51 is positioned. In the operating state of the fuel cell system 1, the second line section 102 is traversed by a second mass flow M3_4, which is greater than the first mass flow Mi_2des the first line section 101, since in the second mass flow M3_4 in addition to the anode gas 52 in the anode gas supply line 53 and the oxygen 19, the from the cathode 12 flows into the anode compartment 13, is taken into account. A variant of the invention is thus carried out with a second mass flow which is larger in comparison with the first mass flow, wherein this ratio can be present at one, several or all pressure measuring points Pi, P2, P3, P4. The pressure measuring point P3 is arranged here in the anode gas outlet 54 upstream of the anode gas heat exchanger 60. The pressure measuring point P4 is disposed downstream of the anode gas heat exchanger 60 in the anode gas drain 54. The second differential pressure loss ΔΡ3_4 is thus determined here along a second line section 102 on the hot heat exchanger side 62 via the anode gas heat exchanger 60. Thus, first ΔΡι_2 and second differential pressure loss ΔΡ3_4 respectively via the cold 61 and the hot heat exchanger side 62 of the same Anodengaswärmeübertragers 60 are determined.
    With a computing unit 201, a differential pressure loss ratio Rap by quotient of the ratio of measured second
    Differential pressure loss ΔΡ3_4 calculated to measured first differential pressure loss ΔΡι_2. An evaluation unit 202 determines the respective recirculation rate RR on the basis of the differential pressure loss ratio Rap determined by the arithmetic unit 201 and on the basis of a characteristic system characteristic S characteristic of the fuel cell system 1 as a function of the respectively calculated differential pressure loss ratio Rap and these are displayed or output by a display unit 203.
    Alternatively, the second differential pressure loss ΔΡ2_3 can also be effected by differential pressure measurement with a second differential pressure loss measuring unit 93, which is positioned with two spaced pressure measuring points P2, P3 along a second and a further line section 103 of the anode gas recirculation line 51. The pressure measuring point P2 is again arranged downstream of the anode gas heat exchanger 60 in the anode gas discharge line 54. The pressure measuring point P3 is arranged here in the anode gas outlet 54 upstream of the anode gas heat exchanger 60. Thus, this second differential pressure loss ΔΡ2_3 is determined via the anode space 13 of the fuel cell 10. It is again true that a mass flow M2_3, which flows in the second or in the further line section 103, here for example, greater than the first mass flow Mi_2 in the first line section 101, wherein for further determination of the recirculation rate RR and this second differential pressure loss .DELTA.Ρ2_3 again with the along the first differential pressure loss .DELTA.ιι_2 is set in relation to the first line section 101.
    Further measuring and / or regulating devices, which may be necessary for carrying out the measuring method according to the invention with the measuring device 200 or for the automatic operation of the fuel cell system and which are not shown in FIG. 4 for reasons of clarity, are those skilled in the field of fuel cells known in itself.
    5 shows a diagram of the measuring method according to the invention for determining the recirculation rate RR in the anode gas circuit 50 on the basis of a system characteristic S characteristic of the respective fuel cell system 1 as a function of the respectively calculated differential pressure loss ratio Rap. The
    System characteristic S, which indicates the relationship between the respective differential pressure loss ratio Rap and the recirculation rate RR, is essentially independent of the current load, as evidenced by the three data series determined at 50%, 75% and 100% current load. In order to further simplify the measuring method according to the invention, it can be assumed, depending on the required accuracy, that the system characteristic S is independent of the current load, in which case the system characteristic S for a fuel cell system 1 is determined independently of each other by determining the differential pressure loss ratios Rap at several different recirculation rates RR the current load is calibrated.
    Alternatively, it may also be assumed that the system characteristic S indicates a linear relationship between the respective differential pressure loss ratio Rap and the recirculation rate RR. In this case, the calibration is further simplified and the determination of the differential pressure loss ratio Rap at at least two different recirculation rates RR is sufficient regardless of the respective current load. If the relationship between the respective differential pressure loss ratio Rap and the recirculation rate RR is not linear but, for example, exponential, the differential pressure loss ratios Rap must be determined for at least three different recirculation rates RR.
    权利要求:
    Claims (14)
    [1]
    claims
    1. A measuring method for determining the recirculation rate (RR) in the anode gas circuit (50) of a fuel cell system (1), which fuel cell system (1) at least one fuel cell (10) with at least one in a cathode compartment (11) arranged cathode (12), with at least one in an anode chamber (13) arranged anode (14) and with a between cathode space (11) and anode space (13) existing electrolyte (15), wherein with an anode gas recirculation line (51) anode gas (52) from the anode space (13) of at least a fuel cell (10) with at least one gas delivery device (70) is supplied and the anode gas (52) in at least one in the Anodengasrezirkulationsleitung (51) arranged anode gas heat exchanger (60) is thermostated, characterized by the following steps: measuring a first differential pressure loss (ΔΡι_2) along a first line section (101) of the anode gas recirculation line (51), which first L in the operating state of the fuel cell system (1), a first mass flow (Mi_2) flows through the fuel supply section (101); Measuring a second differential pressure loss (ΔΡ3_4, ΔΡ2_3) along a second line section (102, 103) of the anode gas recirculation line (52), which second line section (102) in the operating state of the fuel cell system (1) of a second one of different size compared to the first mass flow (Mi_2) Flows through mass flow (M3_4-, M2_3); Calculating the differential pressure loss ratio (Rap) by quotient of the ratio of the measured second differential pressure loss (ΔΡ3_4; ΔΡ2_3) to the measured first differential pressure loss (ΔΡι_2); Determining the recirculation rate (RR) in the Anodengaskreislauf (50) based on a characteristic of the fuel cell system (1) system characteristic (S) as a function of the calculated differential pressure loss ratio (rap).
    [2]
    2. Measuring method according to claim 1, characterized in that the system characteristic (S) as a relationship between the differential pressure loss ratio (Rap) and the recirculation rate (RR) is substantially independent of a current load.
    [3]
    3. Measuring method according to claim 1 or 2, characterized in that the system characteristic (S) indicates a linear relationship between the differential pressure loss ratio (Rap) and the recirculation rate (RR).
    [4]
    4. Measuring method according to one of claims 1 to 3, characterized in that along the system characteristic (S) with increasing recirculation rate (RR), the differential pressure loss ratio (Rap) decreases.
    [5]
    5. Measuring method according to one of claims 1 to 4, characterized in that the system characteristic (S) in each case for a fuel cell system (1) by determining the differential pressure loss ratios (Rap) at different recirculation rates (RR) is calibrated.
    [6]
    6. Measuring method according to one of claims 1 to 5, characterized in that the first differential pressure loss (ΔΡι_2) along a first line section (101) in the anode gas supply line (53) on the cold heat exchanger side (61) of the at least one Anodengaswärmeübertragers (60) is measured and measuring the second differential pressure loss (ΔΡ3_4) along a second conduit section (102) in the anode gas exhaust line (54) on the hot heat exchanger side (62) of the same anode gas heat exchanger (60).
    [7]
    7. Measuring method according to claim 6, characterized in that the first differential pressure loss (ΔΡι_2) in the anode gas supply line (53) on the cold heat exchanger side (61) upstream (Pi) and downstream (P2) of the at least one Anodengaswärmeübertragers (60) is measured and the second differential pressure loss (ΔΡ3_4) in the anode gas drain (54) on the hot heat exchanger side (62) upstream (P3) and downstream (P4) of the same Anodengaswärmeübertragers (60) is measured.
    [8]
    8. Measuring method according to one of claims 1 to 6, characterized in that the first differential pressure loss (ΔΡι_2) in the anode gas supply line (53) on the cold heat exchanger side (61) upstream (Pi) and downstream (P2) of the at least one Anodengaswärmeübertragers (60) is measured and the second differential pressure loss (ΔΡ2_3) along a second line section (103) of the anode gas recirculation line (51) upstream (P2) and downstream (P3) of the anode chamber (13) is measured.
    [9]
    9. Measuring method according to one of claims 1 to 6, characterized in that anode gas (52) with the at least one gas conveying device (70) is fed to a reformer (80).
    [10]
    10. Measuring device (200) for carrying out a measuring method for determining the recirculation rate (RR) in the anode gas circuit (50) of a fuel cell system (1) according to one of the preceding claims 1 to 9, comprising at least a first differential pressure loss measuring unit (91) for determining a first differential pressure loss ( ΔΡ12), which with two spaced pressure measuring points (Pi, P2) positioned along a first line section (101) of an anode gas recirculation line (51), wherein in the operating state of the fuel cell system (1) of the first line section (101) by a first mass flow (Mi_2) flowed through and at least one second differential pressure loss measuring unit (92; 93) for determining a second differential pressure loss (ΔΡ3_4; ΔΡ2_3) having two spaced pressure measuring points (P3, P <P2, P3) along a second line section (102; 103) of the anode gas recirculation line (51) is positioned wherein, in the operating state of the fuel cell system (1), the second line section (102; A second mass flow (M3_4, M2_3) is different in size from the first mass flow (Mi_2) of the first line section (101), and furthermore comprising a computing unit (201) Arithmetic unit (201) a differential pressure loss ratio (Rap) by quotient of the ratio of measured second differential pressure loss (ΔΡ3_4; ΔΡ2_3) to measured first differential pressure loss (ΔΡι_2) is calculated and further comprising an evaluation unit (202), wherein by the evaluation unit (202) based on the calculated Differential pressure loss ratio (Rap) and based on a for the fuel cell system (1) characteristic system characteristic (S) as a function of each calculated differential pressure loss ratio (rap) the respective recirculation rate (RR) can be determined, which recirculation rate (RR) of a display unit (203) can be displayed.
    [11]
    11. Measuring device (200) according to claim 10, characterized in that the arithmetic unit (201), the evaluation unit (202) and the display unit (203) with signal lines (210) are coupled together.
    [12]
    12. Measuring device (200) according to claim 10 or 11, characterized in that the system characteristic curve (S) can be calibrated in each case for a fuel cell system (1) by determining the differential pressure loss ratios (Rap) at different recirculation rates (RR).
    [13]
    13. Measuring device (200) according to any one of claims 10 to 12, characterized in that the system characteristic (S) with a current load independent relationship between the differential pressure loss ratio (Rap) and the recirculation rate (RR) is selectable.
    [14]
    14. Measuring device (200) according to any one of claims 10 to 13, characterized in that the system characteristic (S) with a linear relationship between the differential pressure loss ratio (Rap) and the recirculation rate (RR) is selectable.
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    同族专利:
    公开号 | 公开日
    CN108432019B|2021-01-08|
    US20180375131A1|2018-12-27|
    DE112016005256A5|2018-08-16|
    JP2018538668A|2018-12-27|
    WO2017085133A1|2017-05-26|
    CN108432019A|2018-08-21|
    US10826089B2|2020-11-03|
    AT517685B1|2017-04-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2008034454A1|2006-09-20|2008-03-27|Daimler Ag|Recirculation arrangement for an anode-side gas supply in a fuel cell apparatus and fuel cell apparatus for mobile use|
    US20120174990A1|2007-12-27|2012-07-12|Horiba Stec, Co., Ltd.|Flow rate ratio controlling apparatus|
    DE102009019838A1|2008-05-06|2009-12-17|GM Global Technology Operations, Inc., Detroit|System and method for controlling an anode-side recirculation pump in a fuel cell system|
    CA2597119C|2005-06-13|2013-04-02|Nissan Motor Co., Ltd.|Fuel cell start-up control system|
    US8323841B2|2008-05-06|2012-12-04|GM Global Technology Operations LLC|Anode loop observer for fuel cell systems|
    WO2010058747A1|2008-11-21|2010-05-27|日産自動車株式会社|Fuel cell system and method for controlling same|
    DE102011102336A1|2011-05-25|2012-11-29|Daimler Ag|Recirculation device for a fuel cell system|
    FI123857B|2012-02-10|2013-11-29|Convion Oy|Method and arrangement for utilizing recirculation in a high temperature fuel cell system|
    CN105576268B|2014-10-08|2019-02-15|通用电气公司|System and method for controlling flow-rate ratio|WO2018212214A1|2017-05-18|2018-11-22|株式会社デンソー|Fuel cell system|
    JP2019216091A|2018-06-12|2019-12-19|パナソニックＩｐマネジメント株式会社|Fuel cell system|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA735/2015A|AT517685B1|2015-11-17|2015-11-17|Measuring method and measuring device for determining the recirculation rate|ATA735/2015A| AT517685B1|2015-11-17|2015-11-17|Measuring method and measuring device for determining the recirculation rate|
    CN201680067319.3A| CN108432019B|2015-11-17|2016-11-16|Measuring method and measuring device for determining a recirculation rate|
    JP2018525651A| JP2018538668A|2015-11-17|2016-11-16|Method and apparatus for measuring recirculation rate|
    PCT/EP2016/077873| WO2017085133A1|2015-11-17|2016-11-16|Measuring method and measuring apparatus for determining the recirculation rate|
    DE112016005256.1T| DE112016005256A5|2015-11-17|2016-11-16|Measuring method and measuring device for determining the recirculation rate|
    US15/776,790| US10826089B2|2015-11-17|2016-11-16|Measuring method and measuring apparatus for determining the recirculation rate|
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