Air supply system for a rail vehicle and rail vehicle comprising such an air supply system
A decentralized air supply system for rail vehicles efficiently recirculates compressed air within the system, reducing energy consumption and maintenance costs by utilizing a compressor with a return line and valve system, addressing the challenge of supplying pneumatic components in airless trains.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KB INTELLECTUAL PROPERTY GMBH & CO KG
- Filing Date
- 2026-01-07
- Publication Date
- 2026-07-23
AI Technical Summary
Existing rail vehicles transitioning to compressed air-free systems face challenges in economically supplying pneumatic components with compressed air.
A decentralized air supply system for rail vehicles that includes a compressor with a return line, allowing recirculation of compressed air from consumers back into the compressor, and a valve system to switch between recirculated and ambient air based on pressure differences, along with an expansion air reservoir and optional components like an air dryer and aftercooler.
This system achieves energy savings by reducing the pressure difference needed for compression, minimizing power consumption and maintenance costs, while maintaining reliable operation.
Smart Images
Figure EP2026050210_23072026_PF_FP_ABST
Abstract
Description
[0001] 2024PF00260 January 13, 2025
[0002] 1
[0003] DESCRIPTION
[0004] Air supply system for a rail vehicle and rail vehicle with such an air supply system
[0005] The invention relates to an air supply system for a rail vehicle and a rail vehicle with such an air supply system, in particular for a rail vehicle with electromechanical brakes that does not have a compressed air brake.
[0006] In the past, rail vehicles were generally braked using compressed air brakes. However, with the ongoing development of rail vehicles through digitalization, the use of bus systems to control components, and the increasing replacement of pneumatic systems with electromechanical systems, rail vehicles are evolving towards compressed air-free systems. A train consisting of such vehicles is referred to as an "airless train".
[0007] However, even these so-called airless rail vehicles contain consumers for which the use of compressed air cannot be adequately replaced according to the current state of the art, so the problem is to supply these consumers in an energy-saving and cost-effective manner.
[0008] The object underlying the invention is to provide an air supply system that can economically supply individual pneumatic components of rail vehicles with compressed air without a central compressed air supply.
[0009] The problem is solved by an air supply system according to claim 1 and a rail vehicle according to claim 13. Advantageous further developments of the invention are contained in the dependent claims.
[0010] According to one aspect of the invention, an air supply system for a rail vehicle comprises a compressor configured to provide compressed air for a compressed air consumer and a return line between the 2024PF00260
[0011] 2
[0012] compressed air consumer and the compressor, wherein the compressor has an air inlet which is connected to the return line and is designed to introduce compressed air returned from the compressed air consumer into the compressor.
[0013] The term "rail vehicle" here refers to a single train section or carriage, so a complete train is not considered the rail vehicle.
[0014] The return line is a line that is connected on one side to the compressed air consumer and on the other side to the compressor, although it is not excluded that further pneumatic elements are provided in the return line.
[0015] By introducing recirculated compressed air into the compressor, it is possible to introduce compressed air at a lower pressure level, but higher than ambient pressure, compared to the compressed air supplied from the compressor to the compressed air consumer. This results in energy savings when this recirculated air is compressed, as its pressure is higher than ambient air pressure, thus reducing the pressure difference to the target pressure that the compressor must provide.
[0016] According to an advantageous embodiment of the air supply system, the compressor is designed as a piston compressor.
[0017] In another advantageous embodiment of the air supply system, it has an expansion air reservoir in the return line.
[0018] Advantageously, the compressor is located in the expansion air tank.
[0019] In an advantageous embodiment of the air supply system, the compressor has an elastic mounting device designed to elastically mount the compressor in the expansion air reservoir. 2024PF00260
[0020] 3
[0021] In an advantageous further development, the compressor has a fan wheel designed to swirl air in the expansion air reservoir.
[0022] According to an advantageous embodiment, the expansion air reservoir has a container with an opening and a closing plate for closing the opening, and the compressor is attached to the closing plate.
[0023] In an advantageous further development of the air supply system, it has an air dryer and, in a line between the compressor and the air dryer, an aftercooler, and the air dryer and the aftercooler are attached to the sealing plate.
[0024] Advantageously, the aftercooler is located outside the expansion air reservoir.
[0025] According to a further advantageous embodiment, the air supply system has a valve system that is connected to the air inlet of the compressor, the return line and an ambient air inlet and is designed to switch such that when the pressure of the returned compressed air in the return line is higher than ambient air pressure, the returned compressed air is introduced from the return line into the compressor, and when the pressure of the returned compressed air in the return line is not higher than ambient air pressure, ambient air is introduced into the compressor.
[0026] Advantageously, the valve system is designed to switch automatically depending on a pressure difference between the pressure of the returned compressed air in the return line and the ambient air pressure.
[0027] According to another advantageous embodiment of the air supply system, the air supply system includes a control device, and the valve system is configured to switch in response to the control device. 2024PF00260
[0028] 4
[0029] According to another aspect of the invention, a rail vehicle has a previously described air supply system.
[0030] In an advantageous embodiment of the rail vehicle, the air supply system is decentralized and a connection to another air supply system of a further rail vehicle connected to the rail vehicle is not provided.
[0031] Advantageously, the compressed air consumer has an air spring bellows of an air suspension system of the rail vehicle.
[0032] The invention is explained below by means of exemplary embodiments with reference to the accompanying drawings.
[0033] In particular, it shows:
[0034] Fig. 1 shows a schematic representation of a rail vehicle with an air supply system in a first embodiment;
[0035] Fig. 2 shows a schematic representation of an air supply system in a second embodiment;
[0036] Fig. 3 shows a schematic representation of an air supply system in a third embodiment;
[0037] Fig. 4 is an isometric view of the air supply system in the third embodiment from a rear oblique angle, in which part of a container of an expansion air reservoir is omitted; and
[0038] Fig. 5 is an isometric view of the air supply system in the third embodiment from a front oblique angle. 2024PF00260
[0039] 5
[0040] Fig. 1 shows a schematic representation of a rail vehicle 1 with an air supply system 2 in a first embodiment.
[0041] The rail vehicle 1 is a train component or a wagon which can form a rail vehicle train by connecting it with at least one other rail vehicle.
[0042] The air supply system 2 is decentralized, meaning that there is no central compressed air supply, for example, via a common main air line for the train, and no connection to another air supply system of the other train. The decentralized air supply system therefore supplies only one train section or car with compressed air at a time. In alternative embodiments, several cars coupled together and sharing a common air supply system 2 are defined as the train 1, with a train always consisting of several train 1s. The air supply system 2 is thus used when a train does not have a common main air line and therefore no continuous compressed air connection between the train sections, so that each train section has its own air supply system 2.
[0043] The air supply system 2 comprises a compressor 3 and a supply line 4, wherein the compressor 3 is configured to supply compressed air to a compressed air consumer 5 via the supply line 4. Figure 1 shows two compressed air consumers 5 supplied by the compressor 3. The air supply system 2 also includes a control device (not shown).
[0044] Compressor 3 is a piston compressor driven by an electric motor. In alternative embodiments, compressor 3 is of a different type, for example, a scroll compressor, and / or is driven by a different type of drive, for example, an internal combustion engine.
[0045] The compressed air consumers 5, air springs in the illustrated embodiment, each have two mechanically controlled level control valves 6, two air springs 7, and two reservoirs 8. These components provide an air suspension for a bogie. In this application, the air supply system 2 serves to fill the air springs 7. In alternative embodiments, not all of these components are present; for example, there is no reservoir 82024PF00260.
[0046] 6
[0047] The compressed air consumer 5 is a different type of consumer that can provide return compressed air at a pressure higher than ambient air pressure, i.e., air pressure in an environment outside the air supply system, for example, a door drive. In further alternative embodiments, no mechanically controlled level control valves 6 are provided; instead, the venting of the air springs 7 is electronically controlled.
[0048] Furthermore, the air supply system 2 in the supply line 4 includes a pressure accumulator 9 and a pressure reducing valve 10, which supplies the air springs 7 with compressed air at a reduced pressure. In alternative embodiments, the pressure accumulator 9 and / or the pressure reducing valve 10 are not necessarily provided.
[0049] Furthermore, the air supply system 2 has a return line 11 between the compressed air consumer 5 and the compressor 3. An expansion air reservoir 12 is provided in the return line 11 between the compressed air consumer 5 and the compressor 3. The expansion air reservoir 12 serves as a buffer for the compressed air returned from the compressed air consumer 5. In alternative embodiments, this expansion air reservoir 12 is omitted.
[0050] The compressor 3 has an air inlet 13 which is connected to the return line 11 and only introduces compressed air returned from the compressed air consumer 5 into the compressor 3, so that a closed system is present.
[0051] Fig. 2 shows a schematic representation of an air supply system 2 in a second embodiment.
[0052] A key distinguishing feature of the air supply system 2 of the second embodiment from the air supply system 2 of the first embodiment is that, in addition to the connection with the return line 11, a connection to the environment is provided at the air inlet 13 of the compressor 3, and the air supply system 2 is therefore a so-called semi-open system. In this embodiment, the connection to the environment comprises a check valve 14 as a valve system connected to the environment and the return line 11, a filter 15, and an ambient air inlet 20.
[0053] 7
[0054] This additional connection to the environment makes it possible to introduce compressed air from the return line 11 into the compressor 3 as long as the pressure in the return line 11 is higher than the ambient air pressure, and to introduce ambient air into the compressor 3 when the pressure of the compressed air in the return line 11 is not higher than the ambient air pressure.
[0055] The further features of the invention, already included in the air supply system 2 of the first embodiment, namely the compressor 3, which supplies the compressed air consumer 5, and the return line 11 between the compressed air consumer 5 and the compressor 3, which has the air inlet 13 connected to the return line 11 in order to introduce the compressed air returned from the compressed air consumer 5 into the compressor 3, are also provided here.
[0056] In alternative embodiments, the semi-open system may also include additional compressed air consumers that do not return compressed air.
[0057] Fig. 3 shows a schematic representation of an air supply system 2 in a third embodiment.
[0058] A key distinguishing feature of the air supply system 2 of the third embodiment compared to the air supply system 2 of the second embodiment is that the compressor 3 is arranged within the expansion air reservoir 12. This arrangement applies a pre-pressure to the underside of the compressor 3's piston, which assists in compressing the air, thereby reducing power consumption, torsional vibrations, and noise emissions. Furthermore, the compressor 3 is protected from all harmful environmental influences by operating in completely dry air, which in turn reduces maintenance requirements and corrosion protection costs. In addition, the number of potential leakage points is reduced, thus increasing the reliability of the air supply system 2.
[0059] Furthermore, in the third embodiment of the air supply system 2, a pre-separator 16 and an air dryer 17, as well as a circuit 18 for regenerating the air dryer 17 and the pre-separator 16, are provided in the supply line 4. 2024PF00260
[0060] 8
[0061] Instead of the check valve 14 in the air supply system 2 in the second embodiment, an OR or double check valve 19 is provided as the valve system in the third embodiment. The OR or double check valve 19 is also connected, via the interior of the expansion air reservoir 12, to the return line 11 and, via the filter 15, to the ambient air inlet 20. This allows the OR or double check valve 19 to ensure that, as long as the pressure in the return line 11—in this embodiment specifically in the expansion air reservoir 12—is higher than the ambient air pressure, the compressed air is introduced from the return line 11 into the compressor 3, and, when the pressure of the compressed air in the return line 11 is not higher than the ambient air pressure, the ambient air is introduced into the compressor 3.
[0062] The OR or double check valve 19 in the third embodiment of the air supply system 2 and the check valve 14 (Fig. 2) in the second embodiment of the air supply system 2 switch automatically depending on the pressure difference between the pressure of the compressed air in the return line 11 or in the expansion air reservoir 12 and the ambient air pressure. In an alternative embodiment, the OR or double check valve 19 or the check valve 14 is controlled by a control unit (not shown) of the air supply system 2.
[0063] Fig. 4 shows an isometric view of the air supply system 2 in the third embodiment, in which the compressor 3 is arranged in the expansion air reservoir 12, from a rear oblique angle, with part of a reservoir 21 of the expansion air reservoir 12 omitted.
[0064] The expansion air reservoir 12 comprises the reservoir 21, which has an opening on the side shown on the left in Fig. 4, and a sealing plate 22 that seals the opening in a pressure-tight manner. Furthermore, the expansion air reservoir 12 preferably has a 3-point reservoir mounting device (not shown) by means of which it can be elastically mounted, for example, on a frame of the rail vehicle 1, with the compressed air then being conveyed to the compressed air consumers 5 via an elastic hose 26 (Fig. 2).
[0065] An interface between the container 21 and the closure plate 22 is designed as a flange in the form of a weld neck. In alternative embodiments, a specially machined weld flange can be used. The container 21 and 2024PF00260
[0066] 9
[0067] The closure plates 22 are made of aluminum. This reduces the weight and, due to high machining speeds, enables cost-effective production. Alternative materials, such as container steel or stainless steel, are possible in alternative designs.
[0068] The compressor 3 has an elastic mounting device 23 by means of which it is elastically mounted on the sealing plate 22. In alternative embodiments, the compressor 3 is not mounted by means of the elastic mounting device 23, but rather by means of a rigid mounting device in the expansion air reservoir 12, wherein the compressor 3 is not necessarily attached to the sealing plate 22, but can also be mounted on the reservoir 21.
[0069] Furthermore, the compressor 3 has a fan wheel 24. The fan wheel 24 is driven by the motor of the compressor 3 and circulates the air in the expansion air reservoir 12. This ensures that the temperature of the air in the expansion air reservoir 12 is distributed evenly across a surface of the reservoir 21, allowing the compressor 3 to operate thermally stable within the expansion air reservoir 12. In alternative embodiments, particularly when the compressor 3 is located outside the expansion air reservoir 12, no fan wheel is provided.
[0070] Fig. 5 shows an isometric view of the air supply system 2 of the third embodiment from a front oblique angle.
[0071] As can be seen in Fig. 5, the air dryer 17 and an aftercooler 25 are attached to the end plate 22 of the expansion air reservoir 12, located outside the expansion air reservoir 12. The aftercooler 25 is provided in a duct between the compressor and the air dryer 17 outside the expansion air reservoir 12 and has the form of a coiled pipe. In alternative embodiments, the aftercooler 25 has a different shape, for example, a straight pipe with cooling fins. Furthermore, the air dryer 17 and / or the aftercooler 25 can be located elsewhere or omitted altogether.
[0072] The line between the compressor 3 and the air dryer 17 is preferably as short as possible within the expansion air reservoir 12 and is thermally insulated from the air in the expansion air reservoir 12. 2024PF00260
[0073] 10
[0074] During operation, the air suspensions are supplied with compressed air via the air supply system 2. The air springs 7 are typically maintained at a minimum air pressure that is significantly higher than the ambient air pressure, usually more than 1.5 bar and up to 2.8 bar. When the level of the rail vehicle is controlled via the level control valves 6, the compressed air at this pressure is not released into the environment, as was previously the case, but is collected in the return line 11, preferably in the expansion air reservoir 12, and returned to the compressor 3. This results in a lower pressure difference between the air introduced into the compressor 3 and the air supplied by the compressor to the compressed air consumer 4, namely the air springs 7, than would be the case if ambient air were introduced at ambient air pressure.Since the ideal isothermal compression work is proportional to the logarithm of the compression ratio, making the inlet pressure of the compression absolutely crucial for the power consumption of the compressor 3, and since the introduced air is already dried, thus avoiding drying losses, energy savings are made possible.
[0075] Moist ambient air drawn in from the outside is advantageously dried in the air dryer 17. To regenerate the air dryer 17, the circuit 18 is used to regenerate the air dryer 17 and the pre-separator 16, which discharges dry, depressurized air from the expansion air tank 12 through the air dryer 17 to the outside environment.
[0076] The invention defined in the claims is not limited to the described embodiments. In particular, features described in relation to the embodiments, other described configurations, and further developments of the invention can be combined with one another, provided they are not reasonably mutually exclusive. 2024PF00260
[0077] 11
[0078] REFERENCE MARK LIST
[0079] 1 rail vehicle
[0080] 2 Air supply system
[0081] 3 Compressor
[0082] 4 Supply line
[0083] 5 compressed air consumers
[0084] 6 Level control valve
[0085] 7 air spring bellows
[0086] 8 expansion tanks
[0087] 9 pressure accumulators
[0088] 10 Pressure reducing valve
[0089] 11 Return line
[0090] 12 expansion air reservoirs
[0091] 13 Air intake
[0092] 14 Check valve
[0093] 15 filters
[0094] 16 pre-separators
[0095] 17 air dryers
[0096] 18 Circuit
[0097] 19 OR or double check valve 20 Ambient air inlet
[0098] 21 containers
[0099] 22 Closure plate
[0100] 23 Storage facility
[0101] 24 fan wheel
[0102] 25 aftercoolers
[0103] 26 hose
Claims
2024PF00260 12 PATENT CLAIMS 1. Air supply system (2) for a rail vehicle (1) , wherein the air supply system (2) a compressor (3) designed to supply compressed air to a compressed air consumer (5), and a return line (11) between the compressed air consumer (5) and the compressor (3), and wherein the compressor (3) has an air inlet (13) which is connected to the return line (11) and is designed to introduce compressed air returned from the compressed air consumer (5) into the compressor (3).
2. Air supply system (2) according to claim 1 , wherein the compressor (3) is designed as a piston compressor.
3. Air supply system (2) according to claim 1 or 2, wherein the air supply system (2) has an expansion air reservoir (12) in the return line (11).
4. Air supply system (2) according to claim 3, wherein the compressor (3) is arranged in the expansion air reservoir (12).
5. Air supply system (2) according to claim 4, wherein the compressor has an elastic mounting device (23) designed to elastically mount the compressor (3) in the expansion air reservoir (12).
6. Air supply system (2) according to claim 4 or 5, wherein the compressor (3) has a fan wheel (24) designed to swirl air in the expansion air reservoir (12).
7. Air supply system (2) according to any one of claims 3 to 6, wherein 2024PF00260 13 the expansion air reservoir (12) has a container (21) with an opening and a closing plate (22) for closing the opening, and the compressor (3) is attached to the closure plate (22).
8. Air supply system (2) according to claim 7, wherein the air supply system (2) includes an air dryer (17) and, in a line between the compressor (3) and the air dryer (17), an aftercooler (25), and the air dryer (17) and the aftercooler (25) are attached to the closure plate (22).
9. Air supply system (2) according to claim 8, wherein the aftercooler (25) is arranged outside the expansion air reservoir (12).
10. Air supply system (2) according to one of the preceding claims, wherein the air supply system (2) comprises a valve system connected to the air inlet (13), the return line (11) and an ambient air inlet (20) and configured to switch such that when the pressure of the returned compressed air in the return line (11) is higher than ambient air pressure, the returned compressed air is introduced from the return line (11) into the compressor (3), and when the pressure of the returned compressed air in the return line (11) is not higher than ambient air pressure, ambient air is introduced into the compressor (3).
11. Air supply system (2) according to claim 10, wherein the valve system is designed to switch automatically depending on a pressure difference between the pressure of the recirculated compressed air in the recirculation line (11) and the ambient air pressure.
12. Air supply system (2) according to claim 10, wherein the air supply system (2) has a control device, and the valve system is designed to be controlled by the control device to switch. 2024PF00260 14 13. Rail vehicle (1) with an air supply system (2) according to one of the preceding claims.
14. Rail vehicle (1) according to claim 13, wherein the air supply system (2) is decentralized and a connection to another air supply system of a further rail vehicle connected to the rail vehicle (1) is not provided.
15. Rail vehicle (1) according to claim 13 or 14, wherein the compressed air consumer (5) has an air spring bellows (7) of an air suspension of the rail vehicle (1).