Compressed-air supply unit, vehicle and method for operating a compressed-air supply unit

Abstract

The invention relates to a compressed-air supply unit (10) for a vehicle (50), having: an air compressor (12), which can be connected or is connected to an air supply (11), for providing compressed air (13) at a compressed-air provision connection (15), wherein the air compressor (12) has an air compressor housing (16); a drying device (18), which can be connected or is connected to the compressed-air provision connection (15) via a compressed-air supply line (17), for drying the compressed air (13) provided at the compressed-air provision connection (15), wherein the drying device (18) can be operated in a drying mode (19) and in a regeneration mode (20); a compressed-air supply connection (22), which can be connected or is connected to the drying device (18) via a compressed-air supply line (21), for providing dried compressed air (13) at the compressed-air supply connection (22) in the drying mode (19) of the drying device (18); a regeneration-air line (23) for connecting the compressed-air supply connection (22) or a regeneration-air connection to the drying device (18) for dehumidifying the drying device (18) with regeneration air (14) provided at the compressed-air supply connection (22) or at the regeneration-air connection in the regeneration mode (20) of the drying device (18); and a venting line (24) for connecting the drying device (18) to a vent (25) for discharging the regeneration air (14), wherein the drying device (18) is arranged outside the air compressor housing (16) and the regeneration-air line (23) has a heat transfer portion (26) which is arranged inside the air compressor housing (16).

Description

[0001] Compressed air supply unit, vehicle and method for operating a compressed air supply unit

[0002] The invention relates to a compressed air supply unit for a vehicle. The invention further relates to a vehicle with a compressed air supply unit and a method for operating a compressed air supply unit.

[0003] Compressed air supply units are used in vehicle compressed air systems to supply compressed air to the vehicle's compressed air consumers, such as an air suspension system, a pneumatic braking system, or a sensor cleaning system. To prevent moisture-related corrosion or icing effects in the compressed air piping system of the compressed air supply unit and the compressed air consumers, the supplied compressed air, which is generated by an air compressor through the compression of ambient air, is treated and, in particular, dehumidified by drying. For this purpose, compressed air supply units can include a drying unit, which, depending on the drying principle, can be designed, for example, as a refrigeration dryer, a membrane air dryer, or an adsorption dryer.In the present case, the invention may relate in particular to a compressed air supply unit with a dryer device that can be operated in a drying mode and in a regeneration mode according to the adsorption principle.

[0004] DE 10 2010 036 742 A1 discloses an air dryer of an air supply system, which contains a desiccant and is operated in the operation of the air supply system both in drying mode and periodically in regeneration mode, wherein the air dryer is designed as part of the electric motor and / or the compressor of the air supply system.

[0005] DE 10 2015219 618 A1 describes an integrated air supply unit, in particular for an air suspension system for a motor vehicle, comprising an air compressor with an electric motor, an air dryer, and a pneumatic block, wherein the air compressor and, in part, a switching valve device for airflow control are arranged within the pneumatic block. A first pneumatic line section is provided in the block between the air compressor and the air dryer, and a second pneumatic line section is provided in the block between the air dryer and the switching valve device. The first and second line sections run side by side in the block, in particular so close together that the air in the first and second line sections acts as an air-to-air heat exchanger. The air is dried by means of an adsorbent, which is regenerated with regeneration air when saturated.To increase the regeneration efficiency, a heating element can be arranged in the pneumatic block, especially in the second pipe section, to warm the regeneration air.

[0006] Especially in vehicles where space and weight constraints necessitate the use of compact compressed air supply units and small components, efficient drying of the compressed air and effective regeneration of the desiccant in the dryer are desirable to ensure effective compressed air treatment even with a smaller dryer. The effectiveness of desiccant regeneration can significantly influence drying quality and the usable drying time of the dryer. Depending on the design of the dryer and the compressed air supply unit, as well as the operating method used, rapid and efficient desiccant regeneration is essential.

[0007] Against this background, the invention aims to provide an improved compressed air supply unit for a vehicle, enabling highly efficient regeneration of the desiccant in the dryer unit. Furthermore, the invention aims to provide a vehicle equipped with such a compressed air supply unit and a suitable method for operating such a unit.

[0008] The problem is solved by a compressed air supply unit for a vehicle according to claim 1, a vehicle with a compressed air supply unit according to claim 13, and a method for operating the compressed air supply unit according to claim 14. Advantageous embodiments are disclosed in the dependent claims, the description, and the figures.

[0009] According to the features of independent claim 1, a compressed air supply unit for a vehicle is proposed, comprising an air compressor connectable or connected to an air supply for providing compressed air at a compressed air supply connection, wherein the air compressor has an air compressor housing, a dryer unit connectable or connected to the compressed air supply connection via a compressed air supply line for drying the compressed air provided at the compressed air supply connection, wherein the dryer unit is operable in a drying mode and in a regeneration mode, and a compressed air supply connection connectable or connected to the dryer unit via a compressed air supply line for providing dried compressed air at the compressed air supply connection in the drying mode of the dryer unit.A regeneration air line for connecting the compressed air supply connection or a regeneration air connection to the dryer unit for dehumidifying the dryer unit with regeneration air supplied at the compressed air supply connection or at the regeneration air connection during the regeneration operation of the dryer unit, and a vent line for connecting the dryer unit to a vent for discharging the regeneration air, wherein the dryer unit is arranged outside the air compressor housing and wherein the regeneration air line has a heat transfer section which is arranged inside the air compressor housing.

[0010] In other words, the simplified proposal is to heat the regeneration air flowing through the regeneration air duct using waste heat from the compressor components of the air compressor. This increases the water absorption capacity of the regeneration air and thus improves the efficiency of the regeneration process. By installing only a heat transfer section within the air compressor housing, instead of the entire dryer unit, the waste heat can be used specifically to heat the regeneration air. This ensures that the drying operation of the dryer unit is not affected by the waste heat from the air compressor, and therefore efficient drying of the compressed air is possible at a comparatively low temperature.Utilizing the waste heat from the air compressor allows for the advantageous use of a heat source already present in the compressed air supply unit. This reduces the energy requirement for an additional heating unit to temper the regeneration air, or even eliminates the need for such a unit altogether. Furthermore, the heat absorbed by the regeneration air can contribute to cooling the compressor components of the air compressor. The proposed features are easy to implement, and the dryer unit, for example, is more easily accessible compared to an arrangement within the air compressor housing. This simplifies maintenance tasks such as desiccant replacement.

[0011] The dryer unit of the compressed air supply system can be considered an adsorption dryer. The drying process in adsorption drying is based on a sorption principle. The dryer unit can include a dryer hopper containing a desiccant. The desiccant in the dryer hopper can be a sorbent made of a hygroscopic material, such as zeolite, which absorbs moisture from the compressed air flowing through the dryer hopper. Since the desiccant becomes increasingly saturated, it must be regenerated regularly, meaning the absorbed moisture must be released. For this purpose, the dryer hopper is permeable to regeneration air, which absorbs moisture from the desiccant and can then be discharged, for example, into the surrounding area of ​​the air dryer.The regeneration air can be stored in a reservoir and / or supplied by a partial flow of the compressed air, particularly the dried compressed air. The regeneration air can be supplied, in particular, at the compressed air supply connection of the compressed air supply unit, or alternatively at a separate regeneration air connection. The dryer unit, in particular a dryer tank of the dryer unit, can be permeated by compressed air to be dried in a first flow direction and by regeneration air in a second flow direction opposite to the first. The dryer unit can be operated in drying mode, in regeneration mode, and optionally in standby mode. The drying mode is intended for drying the supplied compressed air.The regeneration mode is intended for regeneration, i.e., dehumidification of the desiccant. In standby mode, the dryer is neither supplied with compressed air to be dried nor with regeneration air. During standby mode, for example, supplied compressed air can be routed via a bypass to the compressed air consumer or storage unit. Standby mode can be activated, for example, when the compressed air supplied by the compressor is sufficiently dry. Generally, the dryer can have a single dryer tank according to a single-tank principle or multiple dryer tanks according to a multi-tank principle.Several dryer containers can, for example, be operated alternately, especially complementarily, in a drying operation in which an adsorption process takes place to dry the compressed air, and in a regeneration operation in which a desorption process takes place to dehumidify the dry air.

[0012] In this context, an air compressor, also called a compressor, is understood to be a device for generating compressed air from ambient air. The air compressor can be designed, for example, as a piston compressor or a rotary compressor. In particular, the air compressor can be designed as a multi-stage air compressor, which allows for a higher pressure level and increased utilization of waste heat. The air compressor can be fluidically connected to the air supply on the inlet side and to the compressed air supply connection on the outlet side. Within the scope of this application, the terms "connectable" and "connected" can indicate a temporary or permanent fluidic connection, whereby a temporary fluidic connection can be interrupted, for example, by means of a shut-off device.The air compressor has an air compressor housing that protectively surrounds the components of the air compressor used for air compression, such as a drive motor, a gearbox and / or a compression chamber.

[0013] In drying mode, the dryer unit can be connected to the compressed air supply connection on the inlet side and to the compressed air supply connection on the outlet side, so that compressed air supplied by the air compressor can be dried and made available. In regeneration mode, the dryer unit can be connected to the compressed air supply connection or a regeneration air connection on the inlet side and to the vent on the outlet side, so that regeneration air can be passed through the dryer unit to dehumidify the drying process and can be discharged into the vicinity of the compressed air supply unit.

[0014] The compressed air supply unit may include a valve arrangement for controlling the compressed air and regeneration air flows within the unit. In particular, the valve arrangement may include at least one valve device for controllably or directionally blocking or opening a section of the compressed air supply line, the compressed air supply line, the regeneration air line, and / or the vent line. For example, by appropriately controlling the valve arrangement, switching between drying operation, regeneration operation, and optionally standby operation may be enabled.

[0015] The compressed air supply unit can include a control unit for controlling the air compressor and the compressed air and regeneration air flows within the unit. The control unit can, for example, be configured to control the air compressor and valves of the valve assembly or a throttling device. Optionally, the compressed air supply unit can include at least one sensor for detecting an environmental condition within the unit, such as temperature and / or humidity in the dryer, and / or a sensor for detecting properties of the compressed air and regeneration air flows, such as a pressure sensor. The at least one sensor can be connected to the control unit via a signal path, and the sensor data can be used to control the air compressor and / or the compressed air and regeneration air flows.

[0016] According to the proposed features, the regeneration air duct includes a heat transfer section located within the air compressor housing. This heat transfer section can be a section of the regeneration air duct that passes through the air compressor housing, i.e., entering and exiting it. The heat transfer section is designed to preheat the regeneration air in the regeneration air duct using waste heat from the air compressor, thus enabling indirect heat transfer from heat-emitting air compressor components to the regeneration air flowing through the heat transfer section.

[0017] The dryer unit, on the other hand, is located outside the air compressor housing, i.e., not inside its interior, so that, for example, a container wall of a dryer container containing the desiccant and a housing wall of the air compressor housing can be spaced apart from each other by the ambient atmosphere or arranged adjacent to each other externally.

[0018] According to one embodiment, a throttling device can be arranged in the regeneration air line between the compressed air supply connection or regeneration air connection and the heat transfer section, and / or within the heat transfer section itself. In other words, a throttling device can be arranged upstream of the heat transfer section (i.e., before the heat transfer section) or within the heat transfer section, viewed in the direction of regeneration air flow. A throttling device allows the regeneration air to be expanded before it flows through the desiccant in the dryer, thus enabling a higher moisture absorption capacity.By arranging the throttling device in the heat transfer section or, viewed in the direction of regeneration air flow, upstream of the heat transfer section, the expanded regeneration air can advantageously exert an improved cooling effect on air compressor components within the air compressor housing. According to one possible design, the throttling device can be configured to control the volume flow of the regeneration air. For this purpose, the throttling device can, for example, have an adjustable opening cross-section, be pulse-switchable, or be switchable in combination with other throttling devices. A controllable volume flow of the regeneration air allows the amount of regeneration air passed through the dryer to be dynamically adjusted to the current degree of regeneration of the desiccant, thus enabling more efficient use of the regeneration air.According to one embodiment, the heat transfer section can be routed through a motor housing and / or a crankcase of the air compressor. These components can be air compressor parts with high heat generation, the waste heat from which can thus be efficiently used to temper the regeneration air. Routing the heat transfer through these air compressor components is possible without impairing the compressor's function. The motor housing can, for example, accommodate a drive motor for a compressor unit of the air compressor. The compressor unit can be, for example, a piston compressor unit if the air compressor is designed as a piston compressor. The crankcase can accommodate a mechanical transmission for transferring the motor power to the compressor unit, for example, to the piston of the piston compressor unit.

[0019] According to one embodiment, the regeneration air line can be configured as a parallel branch line of the compressed air supply line, wherein the regeneration air line has a first line section upstream of the heat transfer section and a second line section downstream of the heat transfer section. In other words, the first line section can be located between the compressed air supply connection and the heat transfer section, and the second line section can be located between the heat transfer section and the dryer unit. "Upstream of the heat transfer section" can refer to a line section through which the regeneration air flows upstream of the heat transfer section.Downstream of the heat transfer section, this can refer to a section of pipe through which the regeneration air flows in the direction of flow after the heat transfer section. The regeneration air line can branch off from the compressed air supply line as a parallel branch line between the dryer unit and the compressed air supply connection, and then rejoin the compressed air supply line at another point. Designing the regeneration air line as a parallel branch line of the compressed air supply line results in a simplified piping system for the compressed air supply unit. With suitable flow control, shared pipe sections and connections of the compressed air supply line can advantageously be used for both the compressed air during the drying operation of the dryer unit and for the regeneration air during the regeneration operation of the dryer unit.According to one embodiment, a controllable valve assembly for the controlled opening and closing of the regeneration air line can be arranged in the first section of the line. This enables active control of the regeneration process and allows it to be coordinated with the operating state of the air compressor. The controllable valve assembly can, in particular, be designed as an electrically controlled valve assembly, for example, as a 2 / 2-way solenoid valve.

[0020] According to one embodiment, a first directionally actuated valve device for the direction-dependent release of the second pipe section can be arranged in the second pipe section of the regeneration air line. The first directionally actuated valve device can, for example, be designed as a check valve. This provides a simple and effective embodiment that prevents backflow of regeneration air to the compressed air supply connection or regeneration air connection during regeneration operation, as well as the entry of dried compressed air from the compressed air supply line into the regeneration air line, which is designed particularly as a parallel branch line, during drying operation of the dryer unit.

[0021] According to one embodiment, a regeneration relay valve can be arranged in the second section of the regeneration air line to release the second section when regeneration air is supplied to the first section. This enables automatic control of the regeneration air flow through the regeneration air line, coordinated with the regeneration operation of the dryer, without requiring separate control of a valve to release the second section. During the drying operation of the dryer, the closed regeneration relay valve can prevent dried compressed air from entering the regeneration air line, which is designed particularly as a parallel branch line, from the compressed air supply line.The regeneration relay valve can, for example, be designed as a 2 / 2-way relay valve, with a control channel between the first pipe section and a control surface of the regeneration relay valve. According to one embodiment, a vent relay valve can be arranged in the vent line to release the vent line when regeneration air is supplied to the first pipe section of the regeneration air line. This allows for automatic release of the vent line coordinated with the regeneration operation of the dryer unit, without requiring separate control of a valve device for releasing the vent line. The vent relay valve can, for example, be designed as a 2 / 2-way relay valve, with a control channel between the first pipe section and a control surface of the vent relay valve.

[0022] According to one embodiment, a common control relay valve can be arranged in the vent line and the regeneration air line. This relay valve is designed to open the vent line and the second section of the regeneration air line when the first section of the regeneration air line is supplied with regeneration air. This allows the control functions for the automatic opening of the vent line and the second section of the regeneration air line to be combined in a single valve unit. The vent relay valve can, for example, be configured as a 4 / 2-way relay valve.

[0023] According to one embodiment, a second directionally actuated valve device can be arranged in the compressed air supply line between branch points of the regeneration air line and the compressed air supply line. This enables a simple way of blocking the flow path of the compressed air supply line to the regeneration air. The second directionally actuated valve device can, for example, be designed as a check valve.

[0024] According to one embodiment, the air supply and venting can be configured as a common environmental access point for the compressed air supply unit. Particularly when the operation of the air compressor and the venting of the dryer unit and adjacent pipe sections are intended to alternate, the fluid connections of the compressed air supply unit to the environment can be advantageously combined. This reduces the complexity and number of components of the compressed air supply unit, for example, with regard to the number of required filter units.

[0025] According to one embodiment, the air supply and venting can be designed as separate environmental inlets of the compressed air supply unit. This can result in system-related advantages during a shutdown process and subsequent run-down of the air compressor.

[0026] The invention also relates to a vehicle, in particular a commercial vehicle, with a compressed air supply unit according to one of the features described above and a compressed air consumer. The compressed air supply unit and the compressed air consumer can be components of a compressed air supply system of the vehicle, which may additionally include a compressed air piping system for connecting the compressed air supply unit and the compressed air consumer, as well as optionally a compressed air reservoir for intermediate storage of compressed air. The compressed air consumer can, for example, be an air suspension system or a pneumatic braking system of the vehicle. The proposed vehicle can also achieve the advantages described above of particularly efficient regeneration of the desiccant in the dryer unit, so that a vehicle with an optimized compressed air supply unit is provided for supplying dried compressed air with high drying quality.Optimizing the compressed air supply unit can have a particularly beneficial effect on the operating efficiency of vehicles with high compressed air consumption, such as commercial vehicles like semi-trailer trucks.

[0027] The invention further relates to a method for operating a compressed air supply unit according to one of the features described above, in which the dryer unit of the compressed air supply unit is operated alternately in a drying mode and in a regeneration mode, wherein compressed air provided in the drying mode is passed through the dryer unit in a first flow direction, wherein regeneration air provided in the regeneration mode is passed through the dryer unit in a second flow direction, wherein the regeneration air in the regeneration mode is led to the dryer unit via a regeneration air line, and wherein the regeneration air is heated in the heat transfer section of the regeneration air line by waste heat from the air compressor before it is passed through the dryer unit.The proposed operating method also achieves the aforementioned advantages of particularly efficient desiccant regeneration in the dryer. According to the method, operation alternates between drying the supplied compressed air and regenerating the desiccant. Specifically, the air compressor for supplying compressed air at the compressed air supply connection can be activated only during the drying operation of the dryer, i.e., it is switched off during regeneration. The second flow direction is, in particular, opposite to the first flow direction.

[0028] According to one embodiment, the method can include a preheating step in which the compressed air supply unit is preheated when the air compressor is activated during operation. This preheating step can be scheduled, in particular, before the initial drying operation of the drying unit. The preheating advantageously brings the components of the compressed air supply unit, including the dryer, to a favorable operating temperature. In particular, the air compressor itself is also heated, enabling efficient preheating of the regeneration air in the heat transfer section. The preheating step can, for example, be performed by running the compressor with normal air compression.

[0029] Alternatively or additionally, the process can include a temperature control step in which waste heat generated by the air compressor is increased by a predefined control profile of the air compressor. Accordingly, the waste heat from the air compressor can be specifically increased to enhance the temperature of the regeneration air by temporarily modifying control parameters compared to normal operation. The temperature control step can be performed, for example, when a predefined ambient temperature is undershot, but can also be carried out independently of the temperature to improve regeneration efficiency. The temperature control step can be performed, for example, while the dryer is operating in drying mode. A temperature control step during regeneration or standby operation is also conceivable.The waste heat generated by the air compressor can be increased, for example, by a targeted increase in power output. The associated increased heat losses can be accepted and used to temper the regeneration air. According to one possible design, the motor windings of the air compressor's drive motor can be specifically energized to generate increased waste heat in the area of ​​the drive motor. In particular, such energizing can be achieved in such a way that no resulting motor torque is generated, for example, by applying essentially identical current to the windings of a permanent magnet three-phase motor. This prevents the formation of a rotating magnetic field and utilizes only the waste heat generated by the energizing process.

[0030] Generally speaking, the words “ein / eine”, unless explicitly defined otherwise, are not to be understood as numerals, but as indefinite articles with the meaning of “at least one”.

[0031] The invention allows for various embodiments and is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. These show, in schematic form:

[0032] Fig. 1 shows a schematic representation of a compressed air supply unit for a vehicle according to a first embodiment;

[0033] Fig. 2 shows a schematic representation of a compressed air supply unit for a vehicle according to a second embodiment;

[0034] Fig. 3 shows a schematic representation of a compressed air supply unit for a vehicle according to a third embodiment;

[0035] Fig. 4 shows a schematic representation of a compressed air supply unit for a vehicle according to a fourth embodiment;

[0036] Fig. 5 shows a vehicle with a compressed air supply unit according to an exemplary embodiment; Fig. 6 shows a simplified flowchart to illustrate a method for operating a compressed air supply unit according to an exemplary embodiment.

[0037] Fig. 1 shows a compressed air supply unit 10 for a vehicle 50, schematically depicted, for example, in Fig. 5, according to a first embodiment. The compressed air supply unit 10 has an air compressor 12, designed, for example, as a multi-stage piston compressor, which is connected to an air supply 11 and serves to provide compressed air 13 at a compressed air supply connection 15. The air compressor 12 has a schematically indicated air compressor housing 16 to protect the components used for air compression, in which, according to the illustrated embodiment, a motor housing 16a and a crankcase 16b of the air compressor 12 are arranged or integrally formed with the air compressor housing 16.

[0038] The compressed air supply unit 10 further comprises a dryer 18, which is connected to the compressed air supply connection 15 via a compressed air supply line 17 and serves to dry the compressed air 13 supplied at the compressed air supply connection 15 by the air compressor 12. The dryer 18 can be considered an adsorption dryer with a dryer container containing a desiccant, which may be designed as a replaceable dryer cartridge. The dryer 18 can be operated in a drying mode 19 and in a regeneration mode 20. In the drying mode 19, supplied compressed air 13 is passed through the dryer 18 in a first flow direction 36, and in the regeneration mode 20, supplied regeneration air 14 is passed through the dryer 18 in a second flow direction 37, opposite to the first flow direction 36.

[0039] The compressed air supply unit 10 also has a compressed air supply connection 22 for providing dried compressed air 13 at the compressed air supply connection 22 during drying operation 19 of the dryer unit 18. The compressed air supply connection 22 is connected to the dryer unit 18 via a compressed air supply line 21. The compressed air supply unit 10 further has a regeneration air line 23 for connecting the compressed air supply connection 22 or a separate regeneration air connection (not shown) to the dryer unit 18. This allows dehumidification of the dryer unit 18 with regeneration air 14 supplied at the compressed air supply connection 22 or at the regeneration air connection during regeneration operation 20 of the dryer unit 18.In addition, the compressed air supply unit 10 has a vent line 24 for connecting the dryer unit 18 with a vent 25 for removing the moisture-containing regeneration air 14.

[0040] Figure 1 shows that the dryer unit 18 is located outside the air compressor housing 16 and that the regeneration air duct 23 has a heat transfer section 26 located inside the air compressor housing 16. The waste heat from compressor components of the air compressor 12 can indirectly heat the regeneration air 14 flowing through the heat transfer section 26, thereby increasing the water absorption capacity of the regeneration air 14 and thus improving the efficiency of the regeneration operation 20. During drying operation 19, however, the dryer unit 18, located outside the air compressor housing 16, is not affected by the waste heat from the air compressor 12, so the efficiency of the drying operation 19 is not impaired. Furthermore, good accessibility to the dryer unit 18 is ensured.The waste heat from the air compressor 12 for tempering the regeneration air 14 is available without any additional energy input, so that an additional heating unit for tempering the regeneration air 14 is unnecessary or can at least be operated with reduced energy consumption. Furthermore, the waste heat absorbed by the regeneration air 14 can be used to improve the cooling effect on the components of the air compressor 12.

[0041] Furthermore, as can be seen in Fig. 1, a throttling device 27 is arranged in the regeneration air line 23 between the compressed air supply connection 22 and the heat transfer section 26. The throttling device 27 can also be arranged within the heat transfer section 26. The throttling device 27 allows the regeneration air 14 to be expanded to increase its water absorption capacity and to improve the cooling effect on air compressor components. It is also conceivable to design the throttling device 27 to be controllable in order to allow control of the volume flow of the regeneration air 14.

[0042] As shown in Fig. 1, the heat transfer section 26 can be routed through the motor housing 16a and the crankcase 16b of the air compressor 12. High heat generation can occur in the area of ​​the motor housing 16a and the crankcase 16b during operation of the air compressor 12, so efficient temperature control of the regeneration air 14 can take place in these areas. Routing the heat transfer section 26 through the motor housing 16a and the crankcase 16b does not impair the function of the compressor components housed therein.

[0043] According to the embodiment shown in Fig. 1, the regeneration air line 23 is designed as a parallel branch line 23' of the compressed air supply line 21. The regeneration air line 23 has a first line section 23a upstream of the heat transfer section 26 and a second line section 23b downstream of the heat transfer section 26. With a parallel branch line 23', a simple design of the piping system of the compressed air supply unit 10 is achieved, in which common line sections and connections of the compressed air supply line 21 can be used for drying operation 19 and for regeneration operation 20.

[0044] As can be seen in Fig. 1, a controllable valve device 28 for the controllable opening and closing of the regeneration air line 23 is arranged in the first line section 23a of the regeneration air line 23, so that active control of the regeneration operation 20 is possible and can be coordinated with an operating state of the air compressor 12. According to the embodiment shown, the controllable valve direction 28 is designed as a normally closed 2 / 2-way solenoid valve with spring return.

[0045] Furthermore, in the second pipe section 23b of the regeneration air line 23, a first directionally actuated valve device 29, designed as a check valve, is arranged for the directionally dependent release of the second pipe section 23b, with which a backflow of regeneration air 14 to the compressed air supply connection 22 and the inflow of dried compressed air 13 from the compressed air supply line 21 into the branch line 23' can be prevented. Between the branch points 23" of the regeneration air line 23 from the compressed air supply line 21, a second directionally actuated valve device 33, designed as a check valve, is arranged in the compressed air supply line 21 to block the flow path of the compressed air supply line 21 for regeneration air 14 during regeneration operation 20.

[0046] According to the embodiment shown in Fig. 1, a vent relay valve 31 is arranged in the vent line 24 to release the vent line 24 when the first section 23a of the regeneration air line 23 is supplied with regeneration air 14, thereby enabling automatic control of the regeneration air flow 14 through the regeneration air line 23, coordinated with the regeneration operation 20. According to the illustrated embodiment, the vent relay valve 31 is designed as a 2 / 2-way relay valve with spring return, wherein a control channel is formed between the first section 23a and a control surface of the vent relay valve 31.

[0047] As can be seen in Fig. 1, the air supply 11 and the vent 25 are designed as a common environmental access 34 of the compressed air supply unit 10, so that a compact design of the compressed air supply unit 10 with a reduced number of components is available.

[0048] Due to the valve positions of the vent valve 31 and the controllable valve assembly 28 in the first line section 23a, which are each in a closed position as shown in Fig. 1, the dryer assembly 18 is operated in drying mode 19 according to the state shown in Fig. 1. The regeneration mode 20 and a flow direction of the regeneration air 14 are therefore indicated by dashed lines.

[0049] Fig. 2 shows a compressed air supply unit 10 for a vehicle 50, schematically depicted in Fig. 5, according to a second embodiment. The compressed air supply unit 10 according to the second embodiment is essentially comparable in its basic structure and fundamental function to the compressed air supply unit 10 according to the first embodiment. However, unlike the first embodiment, in the second embodiment the air supply 11 and the vent 25 are designed as separate ambient inlets 34 of the compressed air supply unit 10, which offers advantages when switching off and shutting down the air compressor 12.

[0050] Fig. 3 shows a compressed air supply unit 10 for a vehicle 50, schematically depicted in Fig. 5, according to a third embodiment. The compressed air supply unit 10 according to the third embodiment is essentially comparable in its basic structure and fundamental function to the compressed air supply unit 10 according to the first embodiment.In contrast to the first embodiment, the third embodiment has a regeneration relay valve 30 in the second pipe section 23b of the regeneration air line 23, instead of a first directionally actuated valve device 29. This regeneration relay valve enables the second pipe section 23b of the regeneration air line 23 to be opened when the first pipe section 23a of the regeneration air line 23 is supplied with regeneration air 14. This allows for automatic control of the regeneration air flow 14 through the regeneration air line 23, coordinated with the regeneration operation 20. According to the illustrated embodiment, the regeneration relay valve 30 is designed as a 2 / 2-way relay valve with spring return, with a control channel formed between the first pipe section 23a and a control surface of the regeneration relay valve 30.

[0051] Fig. 4 shows a compressed air supply unit 10 for a vehicle 50, schematically depicted, for example, in Fig. 5, according to a fourth embodiment. The compressed air supply unit 10 according to the fourth embodiment is essentially comparable in its basic structure and fundamental function to the compressed air supply unit 10 according to the third embodiment. However, unlike the third embodiment, the fourth embodiment provides a common control relay valve 32 in the vent line 24 and in the regeneration air line 23. This valve is designed to release the vent line 24 and the second line section 23b of the regeneration air line 23 when the first line section 23a of the regeneration air line 23 is supplied with regeneration air 14. In other words, the vent relay valve 31 shown in Fig. 3 and the control relay valve 32 shown in Fig. 4 are not used in the fourth embodiment.The three regeneration relay valves 30 shown are combined in a common relay valve unit as a control relay valve 32. According to the illustrated embodiment, the control relay valve 32 is designed as a 4 / 2-way relay valve with spring return, wherein a control channel is formed between the first line section 23a and a control surface of the control relay valve 32.

[0052] Fig. 5 shows a simplified schematic diagram of a vehicle 50 with a compressed air supply unit 10 according to an exemplary embodiment, where the compressed air supply unit 10 is depicted as a component of a compressed air supply system 54. According to the illustrated embodiment, the vehicle 50 is configured as a commercial vehicle 50a with a tractor unit 52 and a trailer 53. As described above and schematically indicated, the compressed air supply unit 10 comprises an air compressor 12 and a dryer unit 18. The compressed air supply unit 10 can, for example, be configured according to one of the embodiments described above and shown in Figs. 1 to 4. Furthermore, a control unit 35 is associated with the compressed air supply unit 10. The control unit 35 can be used to control the air compressor 12 as well as the compressed air and regeneration air flows in the compressed air supply unit 10.For example, the control unit 35 can be configured to control the controllable valve assembly 28. The compressed air supply unit 10 can be connected via compressed air lines 55 of the compressed air supply system 54 to compressed air consumers 51 of the vehicle 50, which can, for example, be designed as air springs of an air suspension system of the vehicle 50. In addition, the trailer 53 has a compressed air reservoir 56 for the intermediate storage of compressed air 13, so that the compressed air consumers 51 of the trailer 53 can be supplied with compressed air 13 as needed. The compressed air reservoir 56 is also connected to the compressed air supply unit 10 of the vehicle 50 via a compressed air line 55. Fig. 6 shows a simplified flowchart to illustrate a method 100 for operating a compressed air supply unit 10 according to an exemplary embodiment.The compressed air supply unit 10 can, for example, be designed according to one of the embodiments described above and shown in Figs. 1 to 4.

[0053] The process 100 begins with the process start 101, which can be triggered by the start-up of the compressed air supply unit 10. Optionally, a preheating step 102 can be performed first, in which the compressed air supply unit 10 is preheated by activating the air compressor 12. Subsequently, the dryer unit 18 of the compressed air supply unit 10 can be operated alternately in a drying mode 19 according to step 103 and in a regeneration mode 20 according to step 104. In the drying mode 19, supplied compressed air 13 is passed through the dryer unit 18 in a first flow direction 36, and in the regeneration mode 20, supplied regeneration air 14 is passed through the dryer unit 18 in a second flow direction 37, opposite to the first flow direction 36.In regeneration mode 20, regeneration air 14 is fed to the dryer 18 via a regeneration air line 23. The regeneration air 14 is heated in the heat transfer section 26 of the regeneration air line 23 by waste heat from the air compressor 12 before being passed through the dryer 18. Optionally, an additional temperature control step 103' can be performed, for example, during drying mode 19, in which waste heat generated by the air compressor 12 is increased by a predefined control profile of the air compressor 12. Drying mode 19 and regeneration mode 20 can be repeated continuously, with an optional standby phase (not shown) being interposed. For example, when the compressed air supply unit 10 shuts down, process 100 can be completed with process end 105.

[0054] With the compressed air supply unit 10, the vehicle 50, and the method 100 for operating the compressed air supply unit 10, as described in the preceding embodiments, efficient and highly effective regeneration of a desiccant in a dryer unit 18 of the compressed air supply unit 10 is possible, thus favorably influencing the drying quality and the effectively usable drying time of the dryer unit 18. This allows for the provision of an improved compressed air supply unit 10 for a vehicle 50, an improved vehicle 50 with such a compressed air supply unit 10, and an improved method 100 for operating the compressed air supply unit 10.

[0055] Reference symbol (part of the description)

[0056] 10 Compressed air supply unit

[0057] 11 Air supply

[0058] 12 air compressors

[0059] 13 Compressed air

[0060] 14 Regeneration air

[0061] 15 Compressed air supply connection

[0062] 16 air compressor housings

[0063] 16a Motor housing

[0064] 16b Crankcase

[0065] 17 Compressed air supply line

[0066] 18 T dryer unit

[0067] 19 T drying operation

[0068] 20 Regeneration operation

[0069] 21 Compressed air supply line

[0070] 22 Compressed air supply connection

[0071] 23 Regeneration air duct

[0072] 23' Branch line

[0073] 23" Junction

[0074] 23a first section of the line

[0075] 23b second line section

[0076] 24 Vent line

[0077] 25 Ventilation

[0078] 26 Heat transfer section

[0079] 27 Throttle device

[0080] 28 controllable valve assembly

[0081] 29 first direction-dependent actuated valve device

[0082] 30 Regeneration relay valve

[0083] 31 Vent relay valve

[0084] 32 Control relay valve

[0085] 33 second direction-dependent valve device

[0086] 34 Surroundings access

[0087] 35 Control unit first flow direction second flow direction Vehicle a Commercial vehicle Compressed air consumer Tractor unit Trailer Compressed air supply system Compressed air line Compressed air reservoir 0 Process 1 Process start 2 Preheating step 3 Drying operation 3' Temperature control step 4 Regeneration operation 5 Process end

Claims

Patent claims 1. Compressed air supply unit (10) for a vehicle (50), comprising: - an air compressor (12) connectable or connected to an air supply (11) for the provision of compressed air (13) at a compressed air supply connection (15), wherein the air compressor (12) has an air compressor housing (16); - a dryer device (18) which can be connected or is connected to the compressed air supply connection (15) via a compressed air supply line (17) for drying the compressed air (13) supplied at the compressed air supply connection (15), wherein the dryer device (18) can be operated in a drying mode (19) and in a regeneration mode (20); - a compressed air supply connection (22) that can be connected or is connected to the dryer unit (18) via a compressed air supply line (21) for the provision of dried compressed air (13) at the compressed air supply connection (22) during drying operation (19) of the dryer unit (18); - a regeneration air line (23) for connecting the compressed air supply connection (22) or a regeneration air connection to the dryer unit (18) for dehumidifying the dryer unit (18) with regeneration air (14) supplied at the compressed air supply connection (22) or at the regeneration air connection during regeneration operation (20) of the dryer unit (18); and - a vent line (24) for connecting the dryer device (18) to a vent (25) for discharging the regeneration air (14); characterized in that the dryer device (18) is arranged outside the air compressor housing (16) and that the regeneration air line (23) has a heat transfer section (26) which is arranged inside the air compressor housing (16).

2. Compressed air supply unit (10) according to claim 1 , characterized in that a throttling device (27) is arranged in the regeneration air line (23) between the compressed air supply connection (22) or regeneration air connection and the heat transfer section (26) and / or in the heat transfer section (26).

3. Compressed air supply unit (10) according to claim 1 or 2, characterized in that the heat transfer section (26) is guided through a motor housing (16a) and / or through a crankcase (16b) of the air compressor (12).

4. Compressed air supply unit (10) according to one of the preceding claims, characterized in that the regeneration air line (23) is designed as a parallel branch line (23a) of the compressed air supply line (21), wherein the regeneration air line (23) has a first line section (23a) upstream of the heat transfer section (26) and a second line section (23b) downstream of the heat transfer section (26).

5. Compressed air supply unit (10) according to claim 4, characterized in that a controllable valve device (28) for controllable release and shut-off of the regeneration air line (23) is arranged in the first line section (23a) of the regeneration air line (23).

6. Compressed air supply unit (10) according to claim 4 or 5, characterized in that a first directionally actuable valve device (29) for directionally dependent release of the second line section (23b) is arranged in the second line section (23b) of the regeneration air line (23).

7. Compressed air supply unit (10) according to one of claims 4 to 6, characterized in that a regeneration relay valve (30) is arranged in the second line section (23b) of the regeneration air line (23) for releasing the second line section (23b) of the regeneration air line (23) when the first line section (23a) of the regeneration air line (23) is supplied with regeneration air (14).

8. Compressed air supply unit (10) according to one of claims 4 to 7, characterized in that a vent relay valve (31) is arranged in the vent line (24) for releasing the vent line (24) when the first line section (23a) of the regeneration air line (23) is supplied with regeneration air (14).

9. Compressed air supply unit (10) according to one of claims 4 to 8, characterized in that a common control relay valve (32) is arranged in the vent line (24) and in the regeneration air line (23), which is designed to release the vent line (24) and the second line section (23b) of the regeneration air line (23) when the first line section (23a) of the regeneration air line (23) is supplied with regeneration air (14).

10. Compressed air supply unit (10) according to one of claims 4 to 9, characterized in that a second directionally actuable valve device (33) is arranged in the compressed air supply line (21) between branch points (23") of the regeneration air line (23) from the compressed air supply line (21).

11. Compressed air supply unit (10) according to one of the preceding claims, characterized in that the air supply (11) and the vent (25) are designed as a common environmental access (34) of the compressed air supply unit (10).

12. Compressed air supply unit (10) according to one of claims 1 to 10, characterized in that the air supply (11) and the vent (25) are designed as separate environmental access points (34) of the compressed air supply unit (10).

13. Vehicle (50), in particular commercial vehicle (50a), with a compressed air supply unit (10) according to one of the preceding claims and a compressed air consumer (51).

14. Method (100) for operating a compressed air supply unit (10) according to one of claims 1 to 12, wherein the dryer device (18) of the compressed air supply unit (10) is operated alternately in a drying mode (19) and in a regeneration mode (20) (103, 104), wherein compressed air (13) provided in the drying mode (19) is passed through the dryer device (18) in a first flow direction (36), wherein regeneration air (14) provided in the regeneration mode (20) is passed through the dryer device (18) in a second flow direction (37). the dryer device (18) is directed, wherein the regeneration air (14) in the regeneration operation (20) is directed to the dryer device (18) via a regeneration air line (23), characterized in that the regeneration air (14) is heated in the heat transfer section (26) of the regeneration air line (23) by waste heat from the air compressor (12) before it is directed through the dryer device (18).

15. Method (100) according to claim 14, characterized in that the method (100) comprises a preheating step (102) in which, upon start-up of the compressed air supply unit (10) by activation of the air compressor (12), the compressed air supply unit (10) is preheated, and / or comprises a temperature control step (103') in which waste heat generated by the air compressor (12) is increased by a predetermined control profile of the air compressor (12).

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