Vehicle having fuel cell system and method for operating same

Abstract

The invention relates to a vehicle (1), in particular a commercial vehicle, having a fuel cell system (3) with a first compressor unit (5) for supplying a fuel cell (13) with compressed air (L); and a second compressor unit (19) for supplying compressed air (L) to a compressed air system (17) of the vehicle (1). According to the invention, the first compressor unit (5) has an outlet (6) which is connected in a fluid-conducting manner to an inlet (24) of the second compressor unit (19) by means of a branch line (10) such that a first partial flow (T1) of compressed air (L) output by the first compressor unit (5) is fed to the fuel cell (13) and a second partial flow (T2) of compressed air (L) output by the second compressor unit (19) is fed to the fuel cell (13). And a second partial flow (T2) of compressed air (L) output by the first compressor unit (5) is fed to the second compressor unit (19).

Description

Technical Field

[0001] The invention relates to a vehicle, in particular a commercial vehicle, having a fuel cell system with a first compressor unit for supplying compressed air to the fuel cell and a second compressor unit for supplying compressed air to a compressed air system of the vehicle. Vehicles of the above-mentioned type are generally known. According to the invention, a compressed air system is understood to be a compressed air architecture of the vehicle, which supplies compressed air via one or more lines to all safety-related and non-safety-related pneumatic consumers of the vehicle, such as, for example, a pneumatic brake system and / or a pneumatic chassis of the vehicle. Due to the special requirements for the control of the fuel cell, the fuel cell system usually has its own dedicated compressor unit for supplying compressed air to the fuel cell. Background Art

[0002] While "conventional" compressors for supplying compressed air systems with compressed air are usually designed to generate high system pressures, which can be in the range of more than 10 bar, sometimes more than 12 bar or significantly higher, and to achieve these pressures are often provided with piston compressors having rotational speeds in the four-digit range while simultaneously delivering relatively low flow rates, the compressor units of fuel cell systems usually have turbo compressors that deliver higher flow rates at relatively low system pressures of the order of 5 bar or less. For this purpose, the compressor units of fuel cell systems are usually operated in the high five-digit rotational speed range.

[0003] The compressed air supply of the compressed air system of the vehicle and the compressed air supply of the fuel cell system function satisfactorily in principle. However, like other components in the vehicle, the compressor unit is also an electrical consumer. During changes in mobility, the energy required for operating the vehicle is increasingly provided in the vehicle in electrical form and pre-stored in corresponding energy storage devices. The requirements for energy efficiency also affect electrical consumers and include the compressor unit. The installation space requirement of the compressor unit is structurally limited. Summary of the invention

[0004] The object of the present invention is to overcome the above challenges as far as possible. In particular, the object of the present invention is to achieve an increase in efficiency in a vehicle of the type described at the outset.

[0005] The present invention solves the object on which the invention is based in a vehicle of the type described at the outset in that a first compressor unit has an outlet which is connected to an inlet of a second compressor unit in a fluid-conducting manner by means of a branch line so that a first substream of compressed air output by the first compressor unit is supplied to a fuel cell and a second substream of compressed air output by the first compressor unit is supplied to the second compressor unit.

[0006] The present invention is based on the following recognition, that is, the second compressor unit responsible for the compressed air system of the vehicle other than the fuel cell must generate a relatively high pressure, but only requires a very small flow, that is, a flow of the order of <1000 l / min at the outlet of the second compressor unit at about 12.5 bar, especially a flow of the order of <500 l / min at the outlet of the second compressor unit at about 12.5 bar. Here, the present invention works by connecting the outlet of the first compressor unit to the inlet of the second compressor unit by means of a branch line. Therefore, the first compressor unit becomes a pre-compressor of the second compressor unit. As a result, the second compressor unit can already start compression work from a higher pressure level, which can lead to a significant reduction in power demand in relation to the two compressor units, and the higher the pressure at the outlet of the first compressor unit, the greater the significant reduction. As a result, the second compressor unit can be dimensioned significantly smaller overall, which brings both cost advantages and reduces the structural space. Since the required additional flow is less than the flow required by the fuel cell, the first compressor unit does not need to be (or in any case does not need to be significantly) larger. In addition to significantly lower power consumption, the series connection of the first compressor unit of the fuel cell system with the second compressor unit of the compressed air system thus also results in further efficiency-enhancing factors. The cost advantages relate in particular to cost-intensive components of the compressor unit, such as the motor and power electronics.

[0007] In an advantageous embodiment, the second compressor unit is connected to the compressed air accumulator in a fluid-conducting manner on the outlet side and is designed to additionally compress the compressed air supplied to it by the first compressor unit and to supply the compressed air to the compressed air accumulator. Depending on how high the pressure level on the outlet side of the second compressor unit is, it may even be advantageous to conduct the compressed air through the second compressor unit without additional compression work to the outlet side, in particular the compressed air accumulator, at least until the pressure level on the outlet side of the first compressor unit has been reached and only then to start the additional compression work.

[0008] In a preferred embodiment, the first compressor unit has an air filter arranged upstream of the branch line. Further preferably, the first compressor unit has a compressor, and the air filter is arranged upstream of the compressor and is set up to filter the air supplied to the first compressor unit before entering the compressor. Depending on the application, a multi-stage compressor can also be used in the compressor unit for the fuel cell system, which therefore has multiple compressor stages. However, in order to understand the present invention, it is sufficient to explain only one single compressor. It should be understood that the present invention is also applicable to compressor units with multiple compressors, in which in principle it is advantageous to position the air filter as far upstream as possible to protect the compressor unit from dirt intrusion.

[0009] In a further preferred embodiment, the fuel cell system, in particular the first compressor unit, is designed to operate with a variable flow rate, and the vehicle has a controller which is designed to generate an air request signal for controlling the flow rate of the first compressor unit. In view of the fact that the additionally required flow rate in the first compressor unit for feeding the branch line is small relative to the flow rate already required by the fuel cell, i.e., typically in the single-digit percentage range relative to the flow rate for the fuel cell, in a preferred embodiment, in particular the control of the rotational speed is sufficient to control the flow rate for the presence of the air request signal.

[0010] If, according to the invention, the flow rate of the compressor unit is mentioned, it is understood that the flow rate is characterized by the mass flow through the compressor unit or also by the volume flow and the pressure through the compressor unit, preferably in each case on the outlet side.

[0011] The air request signal in the sense of the invention represents the additional delivery demand required for the second subflow. The second compressor unit is preferably set up for operation at a constant operating point, and thus when the second compressor unit must start its operation to supply additional compressed air to the compressed air system of the vehicle, it is possible to accurately predict how much flow is required on the side of the first compressor unit, i.e. how much additional delivery demand. The inlet pressure and the outlet pressure of the second compressor unit are known, and the flow through the second compressor unit can be selected so that the second compressor unit can be operated at a favorable operating point.

[0012] All these variables can be known in pre-tests and by system design, so that in the simplest case, the air request signal can be a digital signal with the states "0" (no air request signal) and "1" (air request signal). The air request signal can be transmitted as a predetermined current signal or voltage signal, or as a coded signal, for example via a vehicle bus system, such as a CAN bus.

[0013] In a further preferred embodiment, the first compressor unit is connected to the controller in a signal-conducting manner and is configured to adjust, in particular increase, the flow delivered by it as a function of the air request signal. In other words, if the air request signal is present at the first compressor unit, the first compressor unit regulates its flow so that the fuel cell can be supplied with the first sub-flow and the second compressor unit can be supplied with the second sub-flow.

[0014] The first compressor unit is preferably configured to deliver a first flow in a first operating mode, which is only delivered to the fuel cell when the second compressor unit is inactive, and to deliver a second flow in a second operating mode which is higher than the first flow, and to form a first subflow for the fuel cell and a second subflow for the compressor unit from the second flow when the second compressor unit is active. In other words, the compressor unit is configured to switch from the first operating mode to the second operating mode as soon as an air request signal is present.

[0015] Preferably, the first compressor unit is set up to compress the air in the second operating mode to the same output pressure as in the first operating mode. The pressure is preferably below 5 bar, for example in the range of 2 bar to 4 bar. In this way, the supply of compressed air to the second compressor unit does not impair the operation of the fuel cell system. At the same time, in the simplest case, it is sufficient for this regulation to adjust the operation of the first compressor unit to a higher speed level, which can be known in advance by calculation or experimental means.

[0016] In a further preferred embodiment, the vehicle has a pressure sensor for detecting the air pressure in the compressed air reservoir, and the controller is connected to the pressure sensor in a signal-conducting manner and is configured to generate an air request signal as soon as the air pressure in the compressed air reservoir reaches or falls below a predetermined switch-on pressure. The switch-on pressure is preferably in the range of 10 bar or less. Alternatively or additionally, the compressed air reservoir has a target pressure value, also referred to as an operating pressure, for example a target pressure value in the range of 12.5 bar or more. Preferably, the controller generates an air request signal as soon as the air pressure in the compressed air reservoir falls below the target pressure value by 10% or more.

[0017] In another preferred embodiment, the controller is configured to drive the second compressor unit to compress the compressed air delivered to the second compressor unit after the air request signal is generated. In a preferred first variant, the controller is configured to drive the second compressor unit after the expiration of a predetermined (first) delay time, wherein the delay time is in particular in the range of 0.5 seconds to 3.5 seconds. Preferably, in a second variant, the controller is alternatively or additionally configured to drive the second compressor unit after the first compressor unit transmits a confirmation signal to the controller that the flow rate has been adjusted. In a preferred third variant, the vehicle has a sensor for detecting the flow rate of the first compressor unit, such as a mass flow sensor or a volume flow sensor (preferably in combination with a pressure sensor), and the sensor is connected to the controller or the second compressor unit in a signal-conducting manner and is configured to send a signal representing the flow rate to the respective unit. It is ensured by these adjustments that the second compressor unit does not start compression work too early, which may lead to insufficient compressed air supply to the fuel cell under unfavorable conditions. The upstream activation of the first compressor prevents the second compressor from operating at an inefficient efficiency (or even not operating at all) due to insufficient inlet pressure.

[0018] In a further preferred embodiment, the control unit is designed to put the second compressor unit into an active state as long as the air request signal is present.

[0019] In a further preferred embodiment, the controller is configured to generate an air request signal until the air pressure in the compressed air reservoir reaches or exceeds a predetermined cut-off pressure. The cut-off pressure is preferably in the range of 12.0 bar or above. Alternatively or additionally, the switch-on pressure is in the range of 10% to 15% below the cut-off pressure.

[0020] In a further preferred embodiment, the first compressor unit is configured to adjust, in particular reduce, the flow rate after a predetermined (second) delay time from the cancellation of the air request signal. Preferably, the delay time is in the range of 0.5 seconds to 3.5 seconds. The continuous delivery of a higher flow rate is also used to avoid undersupply.

[0021] In a preferred embodiment, the fuel cell system has a controller, for example a fuel cell controller, which is configured to control the first compressor unit and is connected to the controller in a signal-conducting manner. For example, the connection between the controller of the fuel cell system and the controller of the compressed air system can be ensured by a CAN bus or a similar bus connection. In an alternative preferred embodiment, the controller can also be integrated into the fuel cell controller in a hardware or software manner.

[0022] In a further preferred embodiment, the vehicle has an air treatment module connected downstream of the second compressor unit, wherein the controller is preferably integrated into the air treatment module. It also applies here that the controller can alternatively also be configured as a dedicated independent controller. For example, the controller can alternatively also be assigned to the second compressor unit or can also be integrated in its control unit in the form of hardware or software.

[0023] The above-mentioned air processing module, also referred to as APU, in particular eAPU (Air Processing Unit), preferably includes an air dryer and / or a valve assembly, such as a multi-circuit protection valve and / or a pressure sensor. If the air processing module includes a controller, the controller is preferably also set up to regulate the pressure at the outlet side of the second compressor unit in a flow method, and thus regulate the operation of the compressor, and generate an air request signal as described above. Depending on whether there are other logic units in the vehicle, it may also be meaningful to integrate the controller into other logic units not mentioned here.

[0024] In the previous embodiments, the series connection of the first compressor unit and the second compressor unit has been described, which is always based on the operation of the second compressor unit and the operation of the first compressor unit for precompression. In the operation of the vehicle, the following situation may occur, that is, the first compressor unit does not work, for example, in the case of a fault or when the fuel cell is shut down when driving over a long downhill section or during parking time. Nevertheless, if the operation of the second compressor unit is required in these conditions, in a preferred embodiment, the vehicle has a bypass line that crosses the first compressor unit and leads to the upstream of the second compressor unit. In this way, the inlet for the air to be compressed (which also crosses the first compressor unit) is directly connected to the second compressor unit, and the second compressor unit (even with a lower inlet pressure than for its ideal operation) can be operated while crossing the first compressor unit.

[0025] In an embodiment in which the first compressor unit has at least one compressor (i.e., compressor stage) and the air filter is arranged upstream of the compressor, the bypass line preferably extends from the junction between the air filter and the compressor to the branch line. Thus, even in the case in which the second compressor unit still has to be operated without the first compressor unit, only an air filter is required, which can be assigned to the central inlet of the compressor unit and can perform its duties without interruption even if the first compressor unit is inoperative.

[0026] The invention has been described above with reference to a vehicle according to a first aspect. In another aspect, the invention also relates to a method for operating a vehicle, in particular a commercial vehicle. The invention solves the aforementioned object in this method, wherein the method comprises the following steps:

[0027] - supplying compressed air to the fuel cell by means of a first compressor unit, and

[0028] - supplying compressed air to a compressed air system of the vehicle by means of a second compressor unit, wherein a first substream of the compressed air output by the first compressor unit is fed to the fuel cell and a second substream of the compressed air output by the first compressor unit is fed to the second compressor unit.

[0029] The invention with respect to the second aspect utilizes the same advantages and considerations as for the vehicle according to the first aspect. Preferred embodiments of the vehicle are at the same time preferred embodiments of the method and vice versa.

[0030] In an exemplary preferred embodiment, the method is extended by one, more or all of the following features:

[0031] - additionally compressing the compressed air supplied from the first compressor unit to the second compressor unit and supplying it to the compressed air reservoir; and / or

[0032] - filtering the air delivered to the first compressor unit upstream of the branch line, in particular upstream of the first compressor unit; and / or

[0033] - operating the first compressor unit at a variable flow rate, preferably generating an air request signal to control the flow rate of the first compressor unit once the air pressure in the compressed air reservoir reaches or falls below a predetermined switch-on pressure; more preferably, generating the air request signal until a predetermined switch-off pressure is reached or exceeded; and / or

[0034] - adjusting, in particular increasing, the flow rate delivered by the first compressor unit in dependence on the air request signal;

[0035] - in a first operating mode, a first flow is delivered, when the second compressor unit is not functional, only the first flow is delivered to the fuel cell, and in a second operating mode, a second flow higher than the first flow is delivered, and when the second compressor unit is functional, a first sub-flow for the fuel cell and a second sub-flow for the second compressor unit are formed from the second flow, wherein preferably, in the second operating mode, the air is compressed to the same output pressure as in the first operating mode, and / or the same flow as in the first operating mode is delivered as the second sub-flow as the total flow; and / or

[0036] - after the air request signal is generated, actuating the second compressor unit; and / or

[0037] - adjusting, in particular reducing, the flow rate delivered by the first compressor unit after a predetermined delay time from the cancellation of the air request signal; and / or

[0038] - The first compressor unit is bridged by means of a bypass line which opens upstream of the second compressor unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be described in detail below with reference to the accompanying drawings using preferred embodiments.

[0040] Figure 1 shows a schematic diagram of a vehicle according to a preferred embodiment, and

[0041] Figure 2 Shown according to Figure 1 An exemplary method flow for operating a vehicle. DETAILED DESCRIPTION

[0042] Figure 1 The schematic diagram of a vehicle 1 is shown, which can be, for example, a commercial vehicle. The vehicle 1 has a fuel cell system 3 including a compressor unit 5. The compressor unit 5 has at least one (first) compressor 7 driven by an electric motor 9. The compressor 7 can be, for example, a radial compressor, an axial compressor or a scroll compressor. The compressor unit 5 is configured to draw in air containing oxygen O2 at an inlet 4 and compress it to an output pressure p L1 , and outputs a flow rate D controlled according to the operation of the compressor unit 5 at the outlet 6. Therefore, the compressed compressed air L is delivered to the fuel cell 13 on the cathode side via the main line 8. Optionally, the air humidifier 11 is arranged in the main line 8.

[0043] The fuel cell system 3 includes a controller 15, which can be constructed as one or more structural units and can be, for example, a fuel cell control unit and / or a compressor controller. The controller 15 can be constructed as a dedicated controller or integrated into the fuel cell 13 or the compressor unit 5 in a hardware or software manner.

[0044] In addition to the fuel cell system 3, the vehicle 1 also has a compressed air system 17. The compressed air system 17 is used to supply compressed air L to safety-related and non-safety-related pneumatic consumers of the vehicle 1 and has a dedicated compressor unit 19. The compressor unit 5 of the fuel cell system 3 is therefore a first compressor unit, while the compressor unit 19 of the compressed air system 17 is a separate, dedicated second compressor unit.

[0045] The second compressor unit 19 has an electric motor 21 which is designed to drive a (second) compressor 23 of the second compressor unit 19 , but which can alternatively also be coupled to an internal combustion engine, for example by means of a clutch. The compressor 23 can be, for example, a piston compressor or a scroll compressor.

[0046] The second compressor unit 19 can be designed, for example, as a piston compressor, while the first compressor unit 5 of the fuel cell system is preferably designed as a turbo compressor.

[0047] The second compressor unit 19 of the compressed air system 17 is connected to the outlet 6 of the first compressor unit 5 of the fuel cell system 3 in a fluid-conducting manner via the inlet 24 and the branch line 10. The second compressor unit 19 is configured to convert the compressed air L supplied to the second compressor unit via the branch line 10 from the outlet pressure p of the first compressor unit 5 to the outlet pressure p of the first compressor unit 5. L1 Further compressed to the second output pressure p L2 > p L1 , and outputs the further compressed sub-flow T2 through the outlet 26, while the compressed air L is also output through the main line 8 at p L1 It is sent as the first sub-flow T1 to the fuel cell 13. The total flow D is composed of T1 and T2.

[0048] The compressed air system 17 has an air processing module 27, also referred to as an APU (Air Processing Unit) or an eAPU (electronic Air Processing Unit), connected downstream of the second compressor unit 19. The air processing module 27 is designed to condition the air compressed by the second compressor unit 19, for example to dry it, and to convey it indirectly or directly to a compressed air reservoir 29 connected to the air processing module 27 in a fluid-conducting manner.

[0049] The compressed air system 17 further comprises a controller 31 which can be integrated into the air treatment module 27 by means of software or hardware, for example, or can be a separate controller. The controller 31 of the compressed air system 17 is configured to control the compressor 17 by means of the compressor control signal S C The second compressor unit 19 is driven to operate.

[0050] The control unit 31 is connected to a pressure sensor 33 in a signal-conducting manner, wherein the pressure sensor 33 is configured to detect the air pressure p of the compressed air reservoir 29. S =p L2The pressure sensor 33 is preferably structurally associated with the compressed air reservoir 29 , but may also be arranged in a fluid line between the air processing module 27 and the compressed air reservoir 28 , or integrated into the air processing module 27 .

[0051] The controller 31 is configured to control the compressed air once the pressure p in the compressed air storage 29 is S At or below the predefined switch-on pressure p E , then an air request signal S is sent to the fuel cell system 3 L Preferably, the switch-on pressure p E 10% to 15% or more lower than the actual operating pressure of the compressed air storage, as described in detail in the general section.

[0052] The controller 31 is configured to issue an air request signal S as long as the compressed air storage 29 needs to be fully supplied with compressed air L. L and the compressor control signal S C In particular, the controller 31 is configured to reduce the pressure p of the compressed air storage 29 to S Reaching or exceeding the cut-off pressure p A When the air request signal S is stopped L and the compressor controller signal S C , the shut-off pressure is preferably greater than p E 10%~15% higher.

[0053] Signal S L and S C The generation and closing of can be done simultaneously, but can also be done in stages in time, as shown in reference Figure 2 As elaborated in detail.

[0054] The fuel cell system 3 is configured to be dependent on the air request signal S L The operation of the first compressor unit 5 is switched between the first operating mode B1 and the second operating mode B2. In the first operating mode B1, the first compressor unit 5 is configured to compress and deliver a first flow rate D1, which is sufficient for the operation of the fuel cell 13, especially sufficient for the operation with excess oxygen.

[0055] The first compressor unit 5 is configured to deliver a second flow rate D2 in the second operating mode B2, the second flow rate D2 being greater than the first flow rate D1, so that a second sub-flow T2 is additionally delivered and the output pressure p L1 Not decreasing.

[0056] When the controller 31 of the compressed air system 17 issues a compressor control signal S CWhen the second compressor unit 19 is activated to increase the pressure in the compressed air storage 29, the second operating mode B2 is usually activated. When the second compressor unit 19 is activated, the flow D2 at the outlet 6 of the first compressor unit 5 is divided into a first sub-flow T1 and a second sub-flow T2, wherein preferably, the first sub-flow T1 has a flow rate as high as D1 in the first operating mode B1. The additional flow (D2-D1) flows into the first compressor unit 19 as the second sub-flow T2 through the branch line 10.

[0057] The vehicle 1 has an air filter 34 which is designed to clean the air O2 drawn in by the fuel cell system 3 in a generally known manner before it enters the first compressor unit 5. A further special advantage of the invention is achieved by connecting the first compressor unit of the fuel cell system in series with the second compressor unit 19 of the compressed air system 17: only a single air filter 34 is required for the pollution-free operation of the two compressor units 5, 19. The air filter 34 can be assigned to the fuel cell system 3, but it can also be connected upstream of the fuel cell system 3 as a dedicated component, as in this case Figure 1 The air filter 34 is also active in bypass operation by means of the bypass line 37 and is then used to directly filter the air flow O2 which is only supplied to the second compressor unit 19 while bypassing the first compressor unit 5 .

[0058] The above-mentioned application cases, which are considered as the main application cases, assume the simultaneous operation of the first compressor unit 5 and the second compressor unit 19 in the second operating mode B2, at least for a certain period of time. However, there may be operating conditions in which the first compressor unit 5 cannot be operated, but compressed air is still needed to increase the pressure of the compressed air storage 29. For these conditions, the vehicle 1 has a bypass line 37, which extends from the junction 35 upstream of the compressor 7 to the coupling 41 in the branch line 10. The non-return element 39 prevents an undesired backflow of the compressed air L in the direction of the junction 35.

[0059] Figure 2 Shown according to Figure 1 An exemplary method flow for operating a vehicle 1 is shown.

[0060] In the following description, a plurality of method steps are described and illustrated in sequence. However, in the actual operation of the vehicle 1, these steps do not necessarily have to be performed in this time sequence, but can also be performed at least partially simultaneously. The subsequent description in this sequence is used for a better understanding.

[0061] In the start step 101 of the method 100, the vehicle 1 is operated for driving. Once it is determined in the first decision step 103 that the operation of the fuel cell system 3 is necessary, in the next method step 105, the fuel cell 13 is driven in the first operating mode B1 to deliver a first flow rate D1 of compressed air L. As long as the delivery of compressed air L by means of the first compressor unit 5 is carried out, the supply of compressed air to the fuel cell is carried out in step 102 by means of the first compressor unit.

[0062] If the vehicle 1 requires compressed air from the compressed air system 17 for its operation, this compressed air is provided by the compressed air reservoir 29. As soon as the pressure p S At or below the switch-on pressure p E , the controller 31 generates an air request signal S in step 109 L Therefore, in step 111, in the second operating mode B2, the first compressor unit 5 is prompted to adjust the second flow rate D2. Once it is checked in step 113 that the required flow rate D2 of the two sub-flows T1 and T2 has been reached and / or after the predetermined first delay time t1 has expired, the compressor control signal S is also used in step 115. C The second compressor unit 19 is driven to start operation.

[0063] Therefore, as long as the second sub-flow T2 is delivered through the second compressor unit 19, method step 116 of supplying compressed air L to the compressed air system 17 of the vehicle 1 with the help of the second compressor unit 19 is performed, wherein the first sub-flow T1 of the compressed air L output by the first compressor unit 5 is delivered to the fuel cell 13, and the second sub-flow T2 of the compressed air L output by the first compressor unit 5 is delivered to the second compressor unit 19.

[0064] Air request signal S L As long as the pressure p in the compressed air reservoir 29 S Also must be raised, the simultaneous operation of the two compressor units 5, 19 continues.

[0065] Once the pressure p is known in step 117 S Reaching or exceeding the cut-off pressure p A , then preferably in step 119 after the second delay time t2, in step 121 by closing the compressor control signal S C To adjust the operation of the second compressor unit.

[0066] After preferably reaching the third delay time t3 in step 123, the air request signal S may also be switched off in step 125. LAnd it returns to the operation of only the first compressor unit 5 according to step 105, or returns to the operation of no compressor unit according to step 101.

[0067] In the following, alternative operating situations which may occur will be discussed. If during the operation of the vehicle 1 according to step 101, during the checking according to step 103 it is determined that the operation of the fuel cell system 3 is not required, but in the subsequent step 104 the pressure p in the compressed air accumulator 29 is determined. S Below the switch-on pressure p E , then the compressor control signal S C Transmitted from the controller 31 to the second compressor unit 19 without previously controlling the first compressor unit 5 , see step 106 .

[0068] Therefore, in step 108, the first compressor unit 5 of the fuel cell system 3 is bypassed by means of the bypass line 37. In step 110, the second compressor unit 19 of the compressed air system 17 compresses the air O2 delivered on the inlet side at ambient pressure (or the inlet pressure upstream of the fuel cell system 3) in the third operating mode B3. Preferably, a third flow D3 is delivered, which can correspond to the previously described subflow T2 = (D2-D1), for example.

[0069] Once the pressure p in the compressed air reservoir 29 is determined in step 112 S Greater than or equal to the shut-off pressure p A , then the compressor control signal S C It can be switched off in step 114 and the vehicle can be returned to operation as in step 101 .

[0070] List of reference numerals (part of the description)

[0071] 1 Vehicle

[0072] 3 Fuel Cell System

[0073] 4. Entrance, fuel cell system

[0074] 5. First compressor unit, fuel cell system

[0075] 6. Export, fuel cell system

[0076] 7 (First) Compressor, fuel cell system

[0077] 8 Main Line

[0078] 9 Motor and fuel cell system

[0079] 10 Branch lines

[0080] 11. Humidifier

[0081] 13. Fuel Cell

[0082] 15 Controller, fuel cell system

[0083] 17 Compressed air system

[0084] 19 Second compressor unit, compressed air system

[0085] 21 Motor, compressed air system

[0086] 23 (Second) Compressors and compressed air systems

[0087] 24 Inlet, second compressor unit

[0088] 29 Compressed air storage, compressed air system

[0089] 31 Controller, compressed air system

[0090] 34 Air filter

[0091] 35 Branching towards the bypass line

[0092] 37 Bypass line

[0093] 41 Bypass line connector

[0094] 100 Methods

[0095] 101 First Steps

[0096] 102 Supply of fuel cells

[0097] 103 Determining the operation of fuel cells

[0098] 104 Detection S ≤p E

[0099] 105 Start operation mode B1

[0100] 106 Start driving the second compressor unit

[0101] 107 Detection S ≤p E

[0102] 108 Across the first compressor unit

[0103] 109 Generate air request signal S L

[0104] 110 Start operation mode B3

[0105] 111 Start operation mode B2

[0106] 112 Detection S ≥p A

[0107] 113 Detection D=D2 and / or t1

[0108] 114 Terminate operation mode B3

[0109] 115 Start driving the second compressor unit

[0110] 116 Supplying compressed air systems

[0111] 117 Detection S ≥p A

[0112] 119 Detection t2

[0113] 121 Terminate the control of the second compressor unit and terminate B2

[0114] 123 Detection t3

[0115] 125 End air request signal S L Generation

[0116] B1, B2, B3 operation modes

[0117] D. D1, D2, D3 flow

[0118] L Compressed air

[0119] O2 air

[0120] t1, t2, t3 delay time

[0121] T1, T2 substream

[0122] S L Air delivery signal

[0123] S C Control Signal

[0124] p L1 Output pressure of the first compressor unit

[0125] p L2 Output pressure of the second compressor unit

[0126] p S Air pressure in compressed air storage

[0127] p E Switch-on pressure

[0128] p A Shutoff pressure

Claims

1. A vehicle (1), in particular a commercial vehicle, comprising: A fuel cell system (3) having a first compressor unit (5) for supplying compressed air (L) to a fuel cell (13); and a second compressor unit (19) for supplying compressed air (L) to a compressed air system (17) of the vehicle (1), It is characterized in that The first compressor unit (5) has an outlet (6) which is connected to an inlet (24) of the second compressor unit (19) in a fluid-conducting manner by means of a branch line (10), so that a first subflow (T 1 ) is supplied to the fuel cell (13), and a second substream (T 2 ) is supplied to the second compressor unit (19).

2. The vehicle (1) according to claim 1, in, The second compressor unit (19) is connected to a compressed air reservoir (29) on the outlet side in a fluid-conducting manner and is designed to additionally compress compressed air (L) supplied to the second compressor unit by the first compressor unit (5) and to supply it to the compressed air reservoir (29).

3. The vehicle (1) according to claim 1 or 2, in, The first compressor unit (5) has an air filter (34) arranged upstream of the branch line (10).

4. The vehicle (1) according to claim 3, in, The first compressor unit (5) has a compressor (7), and the air filter (34) is arranged upstream of the compressor (7) and is configured to filter the air (O) supplied to the first compressor unit (5). 2 ) is filtered before entering the compressor (7).

5. The vehicle (1) according to any one of the preceding claims, in, The first compressor unit (5) is configured to deliver a variable flow rate (D; D 1 ;D 2 ) is operated, and the vehicle (1) has a controller (31) configured to generate an air request signal (S L ) to control the flow rate of the first compressor unit (5).

6. The vehicle (1) according to claim 5, in, The fuel cell system 3, in particular the first compressor unit (5), is connected to the controller (31) in a signal-conducting manner and is configured to operate in dependence on the air request signal (S L ) is adjusted, in particular increased, the flow rate (D) delivered by the first compressor unit.

7. The vehicle (1) according to claim 6, in, The first compressor unit (5) is configured to: in a first operating mode (B 1 ), wherein the first flow rate (D1) is delivered to the fuel cell (13) only when the second compressor unit (19) is not functional, and in the second operating mode (B 2 ) is sent out higher than the first flow rate (D 1 ) of the second flow rate (D 2 ), and when the second compressor unit (19) is activated, a first sub-flow (T 1 ) and a second substream (T 2 ).

8. The vehicle (1) according to claim 7, in, The first compressor unit (5) is configured to operate in a second operating mode (B 2 ) to compress the air to the same level as in the first operating mode (B 1 ) in the same output pressure (p L1 ).

9. The vehicle (1) according to any one of claims 5 to 8, The vehicle has a device for detecting the air pressure (p) in the compressed air storage (29). S ) of the pressure sensor (33), in, The control unit (31) is connected to the pressure sensor (33) in a signal-conducting manner and is configured to detect the air pressure (p S ) reaches or falls below the predetermined cut-in pressure (p E ), the air request signal (S L ).

10. The vehicle (1) according to any one of claims 5 to 9, in, The controller (31) is configured to generate the air request signal (S L ), preferably after a predetermined delay time (t 1 ) then controls the second compressor unit (19) to compress the compressed air (L) supplied to the second compressor unit.

11. The vehicle (1) according to any one of claims 5 to 10, in, The controller (31) is configured to: L ), the second compressor unit (19) is placed in an active state.

12. The vehicle (1) according to any one of claims 9 to 11, in, The controller (31) is configured to generate the air request signal (S L ), until the air pressure (p S ) reaches or exceeds the predetermined shut-off pressure (p A ).

13. The vehicle (1) according to any one of claims 5 to 12, in, The fuel cell system (3), in particular the first compressor unit (5), is configured to cancel the air request signal (S L ) from the scheduled delay time (t 2 ,t 3 ) and then adjust, especially reduce the flow rate (D).

14. A vehicle (1) according to any one of claims 5 to 13, in, The fuel cell system (3) has a controller (15) which is designed to control the first compressor unit (5) and is connected to a controller (31) of the compressed air system (17) in a signal-conducting manner.

15. The vehicle (1) according to any one of claims 5 to 14, in, The vehicle (1) has an air treatment module (27) connected downstream of the second compressor unit (19), and wherein the controller (31) is preferably integrated into the air treatment module (27).

16. The vehicle (1) according to any one of the preceding claims, The vehicle has a bypass line (37) which crosses the first compressor unit (5) and opens upstream of the second compressor unit (19).

17. The vehicle (1) according to claim 16, in, The first compressor unit (5) has at least one compressor (7), the air filter (34) is arranged upstream of the compressor (7), and the bypass line (37) extends from a junction (35) between the air filter (34) and the compressor (7) to a branch line (10).

18. Method for operating a vehicle (1), in particular a commercial vehicle, The method The following steps are involved: - supplying (102) compressed air (L) to the fuel cell (13) by means of a first compressor unit (5), and - supplying (116) compressed air (L) to a compressed air system (17) of the vehicle (1) by means of a second compressor unit (19), wherein a first sub-flow (T 1 ) is supplied to the fuel cell (13), and a second sub-flow (T 2 ) is delivered to the second compressor unit (19).

Images