Air dryer assembly, vehicle compressed air supply unit, and vehicle

Abstract

The invention relates to an air dryer assembly (10) for a vehicle compressed air supply unit (40), having an air dryer (11), which can be operated in a drying mode (T) and in a regeneration mode (R); an inlet connection (12), which is connected or can be connected to a compressor outlet line (42), for receiving compressed air (13) to be dried; an outlet connection (15), which is connected or can be connected to a compressed air providing line (43), for providing dried compressed air (13) to a vehicle compressed air system (51);a regeneration connection (16) for providing regeneration air (14), the regeneration connection (16) being formed by the outlet connection (15) or a regeneration connection (16) which is separate from the outlet connection (15), and a regeneration throttle (18) being provided in a regeneration line (17) between the regeneration connection (16) and the air dryer (11); a ventilation connection (19); and a ventilation valve (21), which provided in a ventilation line (20) downstream of the air dryer (11) between the air dryer (11) and the ventilation connection (19), for ventilating the air dryer (11) and / or the vehicle compressed air system (51) as required; and a throttle device (22), which can be actuated on the basis of pressure, for throttling a ventilation air stream (23) in the ventilation line (20) as required.

Description

[0001] Hanover, November 12, 2024

[0002] IP, Rabe, Reichenbach / Kw 303007-DE-NP EM 303007

[0003] AIR DRYER ARRANGEMENT, VEHICLE COMPRESSED AIR SUPPLY UNIT AND VEHICLE

[0004] The invention relates to an air dryer arrangement for a vehicle compressed air supply unit. The invention further relates to a vehicle compressed air supply unit with such an air dryer arrangement and to a vehicle with such a vehicle compressed air supply unit.

[0005] Vehicle compressed air supply units are used in vehicles 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 vehicle compressed air supply unit and the compressed air consumers, the supplied compressed air, which is generated, for example, by a compressor by compressing ambient air, is treated and, in particular, dehumidified by drying. For this purpose, vehicle compressed air supply systems can include an air dryer, which may, for example, be designed as an adsorption dryer.

[0006] DE 102012005303 B4 discloses a compressed air supply system for operating a pneumatic system, in particular an air suspension system of a vehicle, comprising a compressed air supply, a compressed air connection to the pneumatic system, a vent connection to the environment, a pneumatic main line between the compressed air supply and the compressed air connection, which includes an air dryer and a first throttle, and a vent line between the compressed air connection and the vent connection, which includes a second throttle. The nominal diameter of the first throttle and the nominal diameter of the second throttle are adjustable depending on the pressure.

[0007] EP 1 165333 B1 describes an air spring system for a motor vehicle comprising a compressor unit, a storage unit and switching valves, through which the individual air springs of the individual vehicle wheels are supplied with compressed air, wherein a vent line leading to the atmosphere, which can be shut off or opened by a shut-off valve, is provided in the area between the compressor unit and the switching valves and wherein a free flow cross-section of the vent line can be restricted by means of a throttling element.

[0008] When venting an air dryer in an air dryer assembly to reduce pressure, clearly audible venting noises can occur due to high pressure differences between the air dryer assembly and the surrounding area into which the air is being vented. This is particularly relevant after the vehicle's compressed air system has been temporarily filled, and venting the air dryer may be necessary, which, due to a relative pressure of, for example, up to 20 bar within the air dryer, can be accompanied by significant noise emissions. It has already been proposed to provide a pressure-dependent throttle device to throttle the venting airflow in a vent line of the air dryer as needed.Precise control of the throttle device for actuation at high relative pressures in the air dryer area, without impairing the effectiveness and speed of the venting process at lower relative pressures, proves to be not trivial in practice. In particular, fluid-mechanical effects in the piping system of the air dryer assembly, such as dynamic pressure fluctuations, temperature dependencies, or feedback effects when actuating the throttle device, can complicate accurate and demand-based actuation of the throttle device.

[0009] Against this background, the invention aims to provide an improved air dryer arrangement for a vehicle compressed air supply unit, with which the venting processes of the air dryer arrangement can be optimized. This is intended to enable precisely controlled throttling of a venting airflow when required, particularly to reduce noise emissions during venting, without significantly increasing the structural or circuit complexity of the air dryer arrangement. Furthermore, the invention aims to provide an improved vehicle compressed air supply unit and a vehicle with such an improved vehicle compressed air supply unit. This objective is achieved with an air dryer arrangement according to claim 1, a vehicle compressed air supply unit according to claim 9, and a vehicle according to claim 11.Advantageous embodiments are disclosed in the dependent claims, the description and the figures.

[0010] According to the features of independent claim 1, an air dryer arrangement for a vehicle compressed air supply unit is proposed, comprising:

[0011] - an air dryer that can be operated in a drying operation and in a regeneration operation,

[0012] - an input port that can be connected to or is connected to a compressor output line for receiving compressed air to be dried,

[0013] - an outlet connection that can be connected to or is connected to a compressed air supply line for the provision of dried compressed air for a vehicle compressed air system,

[0014] - a regeneration port for supplying regeneration air, wherein the regeneration port is formed by the outlet port or a regeneration port separate from the outlet port, and wherein a regeneration throttle is arranged in a regeneration line between the regeneration port and the air dryer, - a vent port and a vent valve arranged in a vent line downstream of the air dryer between the air dryer and the vent port for venting the air dryer and / or the vehicle compressed air system as required, and

[0015] - a pressure-dependent actuating throttling device for throttling a ventilation airflow in the ventilation line as required,

[0016] wherein the throttling device is designed to be actuated depending on a dryer pressure present in a dryer compressed air path through the air dryer between the regeneration throttle and the throttling device.

[0017] In simplified terms, it is proposed to use the dryer pressure of the air dryer as a control pressure for the pneumatic control of the pressure-dependent throttling device to throttle the venting flow as needed. This is intended to reduce the otherwise clearly audible venting flow at the aforementioned high pressure differences between the air dryer and the environment, while ensuring sufficient venting with less throttled or unthrottled venting flows at lower pressure differences, such as those that can occur during the air dryer's regeneration process. In other words, high air dryer pressures, which cause audibly noticeable venting processes, are directly used as a control criterion for actuating the throttling device.Furthermore, by using the dryer pressure as a control pressure, early activation of the throttling device can be ensured depending on the selected tap position, whereby the venting path can be limited not only at the start of venting, but for example already during a compressor run with regard to the flow rate of the venting stream.

[0018] The dryer pressure used as control pressure can be tapped at a point in the dryer compressed air path where the dryer pressure is static or quasi-static. This could be, for example, in an interior space of the air dryer where, due to low flow velocities, a static component of the dryer pressure predominates over a dynamic component. This allows for precise control of the throttling device relative to a given relative pressure. At the same time, the precisely adjustable control pressure enables a simpler and more accurate design of the throttling device.A static or quasi-static pressure must be distinguished from a dynamic pressure, or a total pressure composed of both dynamic and static pressure, in the compressed air lines of the air dryer assembly. These dynamic and quasi-static pressures can be subject to fluid-mechanical effects such as dynamic pressure fluctuations or temperature dependencies, and therefore may be associated with reduced control accuracy when used as a control pressure compared to a static or quasi-static pressure. Furthermore, even the expansion of the regeneration air as it flows through the regeneration throttle can reduce the flow velocity of the regeneration air. Therefore, it is conceivable to tap into a quasi-static dryer pressure in a dryer air pressure path between the regeneration throttle and the air dryer.The dryer pressure can also be tapped at selected points upstream of the throttling device in the vent line, under flow-optimized conditions, and used to control the throttling device. The pressure-dependent throttling device can, for example, be a switchable or variably adjustable device to allow for either unrestricted or restricted flow and / or different intermediate throttling levels.

[0019] The air dryer of the air dryer assembly can be designed, in particular, as an adsorption dryer. The drying process in adsorption drying is based on a sorption principle. The air dryer can have a dryer hopper in which a desiccant is placed. The desiccant contained in the dryer hopper can be a sorbent made of a hygroscopic material, for example, a zeolite, which removes moisture from the compressed air flowing through the air dryer. Since the desiccant becomes increasingly saturated, it must be regenerated regularly, i.e., the moisture absorbed by the desiccant must be released again. For this purpose, the air dryer is permeable to regeneration air, which removes moisture from the desiccant and can be discharged into the surrounding area of ​​the air dryer.The air dryer can be operated in drying mode for drying compressed air flowing through it in a first direction, and in regeneration mode for regenerating the desiccant of the air dryer by regeneration air flowing through it in a second direction. The regeneration air can be supplied, for example, by a partial flow of the dried compressed air and / or from an intermediate storage tank. The regeneration air can be supplied, in particular, at the outlet connection of the air dryer assembly, or alternatively or additionally at a separate regeneration connection. Depending on the specific embodiment, the regeneration line can simultaneously form an outlet line of the air dryer assembly or be present as a separate regeneration line within the air dryer assembly.A separate regeneration connection can be either external or internal to the air dryer assembly. An external regeneration connection can, for example, be used to connect an external regeneration air source, such as a branch line of a compressed air supply line or an intermediate storage tank. An internal regeneration connection can, for example, be a branch of a branch line of the outlet line. The branch line forming the regeneration line can, for example, be a bypass line to circumvent an outlet check valve of the air dryer assembly.

[0020] The regeneration throttle located in the regeneration line serves to reduce the pressure of the regeneration air supplied to the air dryer, thereby increasing its water absorption capacity. The regeneration throttle can be located, for example, in an outlet line between the air dryer and the outlet connection. Alternatively, the regeneration throttle can be located in a separate regeneration line, such as a bypass line to circumvent an outlet check valve. Depending on the design, the regeneration throttle can be configured to permanently restrict the compressed air flow through it, or, particularly when the outlet line is designed as a regeneration line, it can be switchable so that the regeneration throttle is only effective during the air dryer's regeneration cycle.

[0021] In principle, an air dryer can have a single dryer container according to a single-container principle or several dryer containers according to a multi-container principle. Multiple dryer containers can, for example, be operated alternately, particularly complementarily, in a drying mode where an adsorption process dries the compressed air, and in a regeneration mode where a desorption process dehumidifies the desiccant. Depending on the intended operating environment of the air dryer system, and especially on the type of vehicle intended to house the air dryer system, the dryer container can be a permanently installed unit or a replaceable desiccant cartridge.

[0022] The air dryer assembly can be configured to form a vehicle compressed air supply unit by connecting it to a compressor. The air dryer assembly can be implemented in a vehicle or designed for implementation in a vehicle, for example, having dimensions suitable for vehicles and including an output connection that can be connected to a vehicle compressed air system. The output connection can, for example, be configured as a gallery connection. The air dryer assembly can include a valve arrangement for controlling at least one component of the air dryer assembly.For example, the air dryer assembly can include a changeover valve assembly for switching the air dryer between drying and regeneration modes. This changeover valve assembly can, for example, comprise a combination of a control valve, which can be electrically actuated, and a changeover valve that can be pneumatically actuated by the control valve. The air dryer assembly and / or a vehicle compressed air supply unit comprising the air dryer assembly can include an electronic control unit that can be used to control, for example, a compressor connected to the air dryer assembly and / or the changeover valve assembly described above.

[0023] The vehicle's compressed air system can, for example, include at least one compressed air consumer and / or at least one compressed air reservoir. The vehicle's compressed air system, or a compressed air consumer within the vehicle's compressed air system, can be designed, for example, as an air suspension system, a pneumatic braking system, or a sensor cleaning system.

[0024] The vent line can, for example, branch off from an inlet line of the air dryer assembly that runs between the inlet connection and the air dryer. A vent valve is located downstream of the air dryer in the vent line, between the air dryer and the vent connection. The term "downstream" can refer to the direction of flow of a vent stream from the air dryer to the vent connection. The vent valve can be used to block or open the vent line as needed. The vent valve can be, in particular, a pneumatically or electrically actuated vent valve, whereby, in the case of pneumatic actuation, the vent valve can be connected to an electrically actuated control valve via a signal system.The vent valve can have additional functions related to the air dryer system, for example, serving as a changeover valve for switching between drying and regeneration modes and / or as a safety valve for overpressure limitation in the vent line. Depending on the intended valve functions and the specific design of the air dryer system's piping, the vent valve can be configured, for example, as a 2 / 2-way valve or a 4 / 2-way valve.

[0025] The air dryer, the vent valve, an optional control valve for actuating the vent valve, and other optional components of the air dryer assembly, such as filters, check valves (like an outlet check valve), or safety valves, can be arranged in a common dryer housing. The compressed air and regeneration lines of the air dryer assembly can, for example, be designed as compressed air ducts integrated into the dryer housing. The inlet connection, the outlet connection, an optional separate regeneration connection, and the vent connection can be externally accessible on the dryer housing. Designs are also conceivable in which the air dryer assembly and a compressor of the vehicle's compressed air supply unit are arranged in a common compressed air supply housing.

[0026] According to one embodiment, the throttling device can be configured to be actuated depending on the dryer pressure present in the air dryer and / or the dryer pressure present in the vent line between the air dryer and the throttling device. In these sections of the dryer compressed air path, the dryer pressure can be conveniently tapped as a control pressure for the pressure-dependent throttling device. In particular, the dryer pressure can be tapped directly in the air dryer with a high approximation of a static dryer pressure and minimal flow-mechanical disturbances, thus enabling precise control of the throttling device. Tapping the dryer pressure as a control pressure for the throttling device in the dryer compressed air path between the air dryer and the throttling device can be a particularly practical and simple implementation.

[0027] According to one embodiment, a control input of the throttling device can be directly connected to the air dryer, the regeneration line, or the vent line of the air dryer assembly via a pneumatic control line. This enables direct pressure-dependent actuation of the throttling device. Furthermore, such a control solution is characterized by a simple design, fast response, reliable operation, and reduced electrical circuitry compared to, for example, electrical control methods. The throttling device can therefore be actuated pneumatically, in particular, depending on the dryer pressure.However, it is fundamentally possible to implement pressure-dependent actuation of the throttle device via a pressure sensor in the dryer's compressed air path, combined with electrical control of the throttle device, for example, directly or via an electropneumatic control valve. If the throttle device's control input is connected to the air dryer's vent line, the connection point can be located, for example, in a section of pipe between the air dryer and the throttle device. If the throttle device's control input is connected to the air dryer's regeneration line, the connection point can be located, for example, in a section of pipe between the regeneration throttle and the air dryer.

[0028] According to one embodiment, the throttling device can be designed as a pressure-dependent, switchable throttle valve. This enables a simple design of the throttling device with fast response times and reliable operation. Furthermore, the switchability, which can specifically mean switching between an activated and a deactivated state of the throttling device, allows for either a throttled or unthrottled venting airflow. This allows for the simple and efficient avoidance of noisy venting at high dryer pressures and ensures sufficient and rapid venting at lower dryer pressures. The pressure-dependent, switchable throttle valve can, in particular, be pneumatically actuated. The pressure-dependent, switchable throttle valve can, in particular, be a throttle relay valve.Depending on the specific design, the pressure-dependent switchable throttle valve can be designed, for example, as a 2 / 2-way valve or as a 3 / 2-way valve.

[0029] According to one embodiment, the throttling device can be designed as a pressure-dependent, adjustable proportional valve. This provides a throttling device that is, in particular, continuously adjustable, enabling flexible and continuous adaptation of the throttling device's opening cross-section to the prevailing dryer pressure. The pressure-dependent, adjustable proportional valve can be configured to decrease and increase the opening cross-section of the valve, particularly continuously, depending on the dryer pressure. The pressure-dependent, adjustable proportional valve can, for example, be designed as a medium-controlled proportional valve.

[0030] According to one embodiment, the throttling device can be arranged in the vent line downstream of the air dryer, between the air dryer and the vent valve. In other words, the air dryer can be located upstream of the throttling device in the direction of venting flow, while the vent valve is located downstream of the throttling device. This allows the throttling device to be positioned in a location protected from environmental influences, resulting in a simpler design and more reliable operation. The throttling device can be positioned closer to the vent valve than to the air dryer, allowing a smaller volume of air to escape unthrottled during the initial venting process before the throttling by the dryer pressure-based control takes effect.The throttling device can be positioned closer to the air dryer than to the vent valve, thereby reducing any backflow effects in the vent line caused by actuation of the throttling device.

[0031] According to one embodiment, the throttling device can be arranged in the vent line downstream of the air dryer, between the vent valve and the vent connection. In other words, the air dryer and the vent valve can be arranged upstream of the throttling device when viewed in the direction of venting flow. This ensures that no pressurized volume of air in the line between the throttling device and the vent valve can escape unchecked when venting begins.

[0032] According to one embodiment, the throttling device can be configured to be activated when a predefined air dryer threshold pressure is exceeded. This allows for a reduction in the otherwise clearly audible escaping venting flow at high pressure differentials between the air dryer and the environment, while simultaneously ensuring sufficient venting with less throttled or unthrottled venting flows at lower pressure differentials, such as those that may occur during the air dryer's regeneration cycle. The throttling device can, for example, be designed to activate when the predefined air dryer threshold pressure is exceeded. Additionally, the throttling device can be configured to remain deactivated or be deactivated when the predefined air dryer threshold pressure is undershot.If the pressure-dependent throttling device is configured, for example, as a pressure-dependent switching throttle valve, it can be set to switch to a throttling position when a design-adjustable air dryer threshold pressure is exceeded, in which the exhaust airflow through the throttle valve is throttled. The pressure-dependent switching throttle valve can also be set to switch to an enabling position when the design-adjustable air dryer threshold pressure is undershot, in which a maximum opening cross-section is set and the exhaust airflow can pass through the throttle valve essentially unrestricted. According to a non-restrictive numerical example, a suitable air dryer threshold pressure could, for example, correspond to a relative pressure between 8 and 12 bar, in particular around 10 bar.Suitable air dryer threshold pressures can generally be determined individually depending on other parameters, particularly acoustic parameters. Such acoustic parameters can relate, for example, to a silencer provided at the vent connection or the positioning of the air dryer assembly within the vehicle. The positioning of the air dryer assembly within the vehicle can take into account proximity to vehicle occupants, vibration excitation of surrounding components, or a flow path of the supplied compressed air determined by the positioning of the air dryer assembly.

[0033] According to one embodiment, the predefined air dryer threshold pressure can deviate from a safety threshold of an overpressure limiter in the dryer's compressed air path and / or in the vent line. In other words, the control of the throttling device using the dryer pressure as a control pressure can be independent of an overpressure limiter in the air dryer assembly. For example, a pneumatic control input of the vent valve can be connected to the vent line via a safety control line and, if the safety threshold (which can be set on the vent valve, for example) is exceeded, actuate the vent valve to vent the vent line. The aforementioned air dryer threshold pressure can, however, be advantageously designed specifically to reduce noise emissions without having to consider safety pressure values ​​with regard to an overpressure limiter.

[0034] The vent connection allows the vent line for venting the air dryer assembly to be connected to the environment of the air dryer assembly, for example for venting the air dryer as needed after a temporarily completed filling of the vehicle compressed air system, during the regeneration operation of the air dryer or in the event of a desired or necessary pressure reduction in the vehicle compressed air system, for example in the event of vehicle lowering by means of a vehicle compressed air system designed as an air suspension system.

[0035] According to one embodiment, the predefined air dryer threshold pressure can be designed such that the throttling device is actuated when the air dryer is vented after the vehicle's compressed air system has been temporarily filled. In particular, the predefined air dryer threshold pressure can be designed such that the throttling device remains inactive during regeneration and / or when the pressure in the vehicle's compressed air system drops. This allows throttled venting to be limited to the specific case of a venting system restricted to the air dryer, where a high dryer pressure is present, increasing the risk of noisy venting.During regeneration, the regeneration airflow is already throttled by the regeneration throttle, thus eliminating the need for further pressure reduction. A controlled pressure drop in the vehicle's compressed air system can be managed in such a way as to avoid acoustically significant venting flows. In these cases, unrestricted and rapid venting can therefore be ensured. The invention also relates to a vehicle compressed air supply unit with a compressor and an air dryer arrangement according to one of the features described above. The proposed vehicle compressed air supply unit also provides the advantages described above of precisely controlled throttling of a venting airflow when required, particularly for reducing noise emissions during venting, without significantly increasing the design or circuit complexity of the air dryer arrangement.The vehicle compressed air supply unit is therefore characterized by reduced noise levels during venting processes, but has a simple design, is inexpensive to manufacture and easy to install in a vehicle.

[0036] By providing a compressor in conjunction with an air dryer assembly according to the aforementioned specifications, a practical vehicle compressed air supply unit can be obtained with an optimally matched design of the compressor and air dryer assembly. Furthermore, the vehicle compressed air supply unit can, for example, include a control unit for managing the compressor and air dryer assembly to enable coordinated and efficient control of both. The compressor can, for example, be designed as a two-stage compressor to provide high compression capacity. The compressor can be connected to the inlet port of the air dryer assembly via a compressor outlet line.According to one possible design, the vent connection of the air dryer assembly can also serve as the intake connection for the compressor, and the compressor and the air dryer assembly can share a combined intake and vent line. This allows for a shared venting and exhaust path in sections of the vehicle's compressed air supply unit. This enables the provision of a compact vehicle compressed air supply unit with a simple design. For example, the aforementioned control unit can be used to coordinate compressor operation and the venting processes of the air dryer assembly.

[0037] According to one embodiment, the compressor can have a compressor housing, wherein the regeneration line of the air dryer assembly is designed as a bypass line to circumvent an outlet check valve of the air dryer assembly, and wherein the regeneration line has a heat transfer section located within the compressor housing. This allows the regeneration air flowing through the regeneration line to be heated by waste heat from compressor components of the compressor, thereby increasing the water absorption capacity of the regeneration air and thus improving the efficiency of the regeneration process. By utilizing the waste heat from the air compressor, a heat source already present in the vehicle's compressed air supply unit can be advantageously used to temper the regeneration air.As a result, the expansion of the regeneration air by the regeneration throttle and the heating of the regeneration air by compressor waste heat, in combination, enable particularly efficient regeneration by significantly increasing the regeneration air's water absorption capacity. This optimized regeneration allows, for example, a faster switch from regeneration to drying mode and a reduction in the overall cycle time for both drying and regeneration.If a shortened cycle time necessitates more frequent venting of the air dryer assembly, this can be achieved, if necessary, by means of the proposed throttling device, which is actuated depending on the dryer pressure, with throttled venting flows such that the noise exposure for vehicle occupants of a vehicle equipped with the vehicle's compressed air supply unit, or for other road users, is significantly reduced over a defined period. The regeneration line, designed as a bypass line, can, for example, be connected to an outlet line of the air dryer assembly at a first position between the air dryer and the outlet check valve, and at a second position between the outlet check valve and the outlet port of the air dryer assembly.

[0038] The invention also relates to a vehicle with a vehicle compressed air supply unit according to one of the features described above and a vehicle compressed air system. The proposed vehicle can also achieve the advantages described above of reduced noise pollution through precise differentiation between exhaust flows that need to be throttled and acoustically less relevant exhaust flows that can escape as freely as possible. Such optimization of venting processes can be particularly advantageous in vehicles with high compressed air consumption and high system pressures, as is the case, for example, with commercial vehicles such as trucks or buses. The vehicle can therefore be designed, for example, as a commercial vehicle. It is also conceivable that the vehicle could be designed as a passenger car.For example, the vehicle's compressed air system or a compressed air consumer within the vehicle's compressed air system can be configured as a sensor cleaning system, an air suspension system, or a pneumatic braking system. The vehicle's compressed air system can be connected, for instance, to the outlet of the air dryer assembly of the vehicle's compressed air supply unit via a compressed air supply line. The vehicle's compressed air system can include an intermediate storage tank for dried compressed air. If the air dryer assembly has a separate regeneration connection, this can be supplied with regeneration air as needed, for example, via a branch line of the compressed air supply line or from the intermediate storage tank.

[0039] 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”.

[0040] 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:

[0041] Fig. 1 shows a schematic representation of a vehicle compressed air supply unit with an air dryer arrangement according to a first embodiment; Fig. 2 shows a schematic representation of a vehicle compressed air supply unit with an air dryer arrangement according to a second embodiment; Fig. 3 shows a schematic representation of a vehicle compressed air supply unit with an air dryer arrangement according to a third embodiment; Fig. 4 shows a schematic representation of a vehicle compressed air supply unit with an air dryer arrangement according to a fourth embodiment; Fig. 5 shows a schematic representation of a vehicle compressed air supply unit with an air dryer arrangement according to a fifth embodiment; Fig. 6 shows a schematic representation of a vehicle designed as a passenger car with a vehicle compressed air supply unit; and

[0042] Fig. 7 shows a schematic representation of a vehicle designed as a truck with a vehicle compressed air supply unit.

[0043] Fig. 1 shows a schematic diagram of a vehicle compressed air supply unit 40 according to a first embodiment. The vehicle compressed air supply unit 40 comprises a compressor 41 and an air dryer assembly 10. The air dryer assembly 10 serves to condition and dry the compressed air 13 supplied by the compressor 41. The compressed air dried by the air dryer assembly 10 can be supplied to a vehicle compressed air system 51 of a vehicle 50, illustrated, for example, in Figs. 6 and 7.

[0044] The air dryer assembly 10 comprises an air dryer 11, which is designed as an adsorption dryer and may include a dryer hopper containing a desiccant. The air dryer 11 can be operated in a drying mode T, in which the compressed air 13 supplied by the compressor 41 is dried, and in a regeneration mode R, in which the desiccant of the air dryer 11 can be regenerated by flowing regeneration air 14 through it. The air dryer assembly 10 has an inlet port 12 connected to a compressor outlet line 42 for receiving the compressed air 13 to be dried and an outlet port 15 connected to a compressed air supply line 43 for supplying the dried compressed air 13 to the vehicle compressed air system 51.

[0045] According to the embodiment shown in Fig. 1, the outlet port 15 is also designed as a regeneration port 16 for supplying regeneration air 14. An outlet line 31 between the air dryer 11 and the outlet port 15 is also designed as a regeneration line 17, which connects the regeneration port 16 to the air dryer 11. Regeneration air 14 can, for example, be supplied to the regeneration port 16 from a branch line of the compressed air supply line 43. A regeneration throttle 18 is arranged in the regeneration line 17 between the regeneration port 16 and the air dryer 11. The air dryer assembly 10 also has a vent port 19.According to the illustrated embodiment, the vent port 19 of the air dryer assembly 10 is also designed as the intake port of the compressor 41 in order to provide a compact vehicle compressed air supply unit 40 with a simple design. The vent port 19 is connected to the air dryer 10 via a vent line 20. A vent valve 21 is arranged in the vent line 20 for venting the air dryer 11 and / or the vehicle compressed air system 51 as needed. The vent valve 21 is also designed as a changeover valve 27 for switching the air dryer 11 between drying mode T and regeneration mode R and can be pneumatically actuated by an electrically actuated control valve 30. According to the illustrated embodiment, the vent valve 21 is designed as a 4 / 2-way valve.The vent valve 21 can be switched between a drying operating position and a regeneration operating position, the regeneration operating position corresponding to a release position for releasing the vent line 20 in the direction of the vent connection 19.

[0046] The air dryer assembly 10 has a pressure-dependent actuating throttle device 22 for throttled a venting flow 23 in the vent line 20 as required. The throttle device 22 is designed to be actuated depending on the dryer pressure PT present in a dryer compressed air path 24 leading through the air dryer 11 between the regeneration throttle 18 and the throttle device 22. By using the dryer pressure PT as the control pressure for actuating the throttle device 22, high air dryer pressures, which are the cause of acoustically noticeable venting processes, can be used as a control criterion, and undesirable noise emissions from the air dryer assembly 10 can be reduced by throttling correspondingly pronounced venting flows 23.At the same time, at lower pressure values, for example during the regeneration cycle R of the air dryer 11, sufficient venting can be achieved with less throttled or unthrottled venting flows 23. By tapping the dryer pressure PT in the dryer compressed air path 24, a precise controllability of the throttling device 22 is ensured due to the static or quasi-static dryer pressure PT present in this area. As can be seen in Fig. 1, the throttling device 22 is designed to be actuated depending on the dryer pressure PT present in the vent line 20 between the air dryer 11 and the throttling device 22, thus providing a simple and practical implementation.For this purpose, a control input 22a of the throttling device 22 is directly connected to the vent line 20 of the air dryer assembly 10 via a pneumatic control line 22b, thus enabling a simple design of the pressure-dependent actuated throttling device 22 with reliable operation. The throttling device 22 is designed as a pressure-dependent switchable throttle valve 22' and, according to the embodiment shown in Fig. 1, is configured as a 2 / 2-way valve. This results in a simple design of the throttling device 22 with well-defined switching states with respect to activated or deactivated throttling. As can also be seen in Fig. 1, the throttling device 22 is arranged in the vent line 20 between the air dryer 11 and the vent valve 21, thereby achieving a positioning of the throttling device 22 protected from environmental influences.

[0047] Figure 1 schematically illustrates that the throttling device 22 is configured to be actuated when a predefined air dryer threshold pressure ps is exceeded. In the state shown in Figure 1, the dryer pressure PT is lower than the air dryer threshold pressure ps, so the throttling device 22 is in a first switching state in which a maximum opening width of the throttling device 22 is set and the venting flow 23 can flow through the throttling device 22 essentially unthrottled. The throttling device 22 can be designed such that, as soon as a control pressure corresponding to the air dryer threshold pressure ps, represented by the dryer pressure PT, is present at the control input 22a, it is switched to a second switching state in which the venting flow 23 is throttled.

[0048] Figure 1 also shows that an overpressure limiter 25 is implemented at the vent valve 21 by providing, in addition to a control input for controlling the vent valve 21 via the control valve 30, a further control input on the vent valve 21, which is connected to the vent line 20 by a pneumatic control line. If a control pressure representing the pressure in the vent line 20 exceeds a safety threshold pu, the vent valve 21 automatically switches to a release position to open the vent line 20 towards the vent port 19, thus implementing the overpressure limiter 25. This prevents impermissible overpressure in the piping system of the air dryer assembly 10. The predefined air dryer threshold pressure ps, above which the throttle device 22 is actuated, differs in particular from the safety threshold pci.The control of the throttling device 22 is therefore designed independently of the overpressure limiter 25 and serves in particular to reduce acoustically clearly perceptible venting flows 23 and not to prevent overpressure in the vent line 20 of the air dryer assembly 10. The predefined air dryer threshold pressure ps can in particular be designed such that the throttling device 22 is actuated when the air dryer 11 is vented after a temporary completion of filling the vehicle compressed air system 51, so that venting in connection with regeneration of the air dryer 11 or with a pressure drop in the vehicle compressed air system 51 is not associated with a throttling of the respective venting flow 23.

[0049] Fig. 2 shows a schematic diagram of a vehicle compressed air supply unit 40 according to a second embodiment. The vehicle compressed air supply unit 40 according to the second embodiment is comparable to the vehicle compressed air supply unit 40 according to the first embodiment with regard to its basic structure and basic function. In contrast to the vehicle compressed air supply unit 40 according to the first embodiment, the pressure-dependent switching throttle device 22 is designed as a 3 / 2-way valve. This also enables a simple design of the pressure-dependent switching throttle device 22* with fast response times and reliable operation, whereby the pressure-dependent switching throttle valve 22' allows switching from an unthrottled venting flow 23 to a throttled venting flow 23 as needed.

[0050] Fig. 3 shows a schematic diagram of a vehicle compressed air supply unit 40 according to a third embodiment. The vehicle compressed air supply unit 40 according to the third embodiment is comparable to the vehicle compressed air supply unit 40 according to the first embodiment with regard to its basic structure and basic function. In contrast to the vehicle compressed air supply unit 40 according to the first embodiment, the throttling device 22 is designed here as a pressure-dependent adjustable continuous valve 22", which allows stepless adjustment of the opening cross-section of the throttling device 22 to a given dryer pressure PT. A design of the throttling device 22 as a pressure-dependent adjustable continuous valve 22" can also be implemented in principle in the other described embodiments.

[0051] As can be seen in Fig. 3, the throttling device 22 is also designed to be actuated depending on the dryer pressure PT present in the air dryer 11. Due to the low flow-mechanical disturbances and low flow velocities in the air dryer 11, it is possible to tap the nearly static dryer pressure PT as a control pressure. For this purpose, a control input 22a of the throttling device 22 is directly connected to the air dryer 11 via a pneumatic control line 22b. Actuating the throttling device 22 depending on the dryer pressure PT present in the air dryer 11 can also be implemented in the other described embodiments.

[0052] Fig. 4 shows a schematic diagram of a vehicle compressed air supply unit 40 according to a fourth embodiment. The vehicle compressed air supply unit 40 according to the fourth embodiment is comparable to the vehicle compressed air supply unit 40 according to the first embodiment with regard to its basic structure and basic function. In contrast to the vehicle compressed air supply unit 40 according to the first embodiment, the throttling device 22 is arranged in the vent line 20 between the vent valve 21 and the vent connection 19. This prevents a portion of the vent flow 23 from escaping unthrottled before the throttling device 22 is activated at the beginning of a venting process. Such an arrangement of the throttling device 22 can also be implemented in the other described embodiments.Figure 5 shows a schematic diagram of a vehicle compressed air supply unit 40 according to a fifth embodiment. The vehicle compressed air supply unit 40 comprises a compressor 41 and an air dryer assembly 10. The air dryer assembly 10 includes an air dryer 11, which can be operated in a drying mode T and in a regeneration mode R. The air dryer assembly 10 has an inlet port 12, connectable to a compressor outlet line 42, for receiving compressed air 13 to be dried, and an outlet port 15, connectable to a compressed air supply line 43, for supplying the dried compressed air 13 to a vehicle compressed air system 51.

[0053] The air dryer assembly 10 has an internal regeneration port 16, separate from the outlet port 15, which is formed by a branch of a branch line of the outlet line 31. The branch line forms a regeneration line 17 of the air dryer assembly 10 and is designed as a bypass line 17' to bypass an outlet check valve 26 of the air dryer assembly 10. The bypass line 17' is connected to the outlet line 31 of the air dryer assembly 10 at a first position between the air dryer 11 and the outlet check valve 26, and at a second position between the outlet check valve 26 and the outlet port 15 of the air dryer assembly 10. A regeneration throttle 18 is arranged in the regeneration line 17 between the regeneration port 16 and the air dryer 11.Furthermore, an electrically controlled regeneration valve 28 and a regeneration check valve 29 are arranged in the regeneration line 17. The regeneration valve 28 allows the regeneration line 17 to be opened for the flow of regeneration air 14 during regeneration mode R of the air dryer 11. The regeneration check valve 29 prevents the outflow of dried compressed air 13 into the regeneration line 17 during drying mode T of the air dryer 11.

[0054] The air dryer assembly 10 further comprises a vent connection 19 and a vent valve 21 arranged in a vent line 20 between the air dryer 11 and the vent connection 19 for venting the air dryer 11 and / or the vehicle compressed air system 51 as needed. According to the illustrated embodiment, the vent connection 19 of the air dryer assembly 10 is also designed as the intake connection of the compressor 41 in order to provide a compact vehicle compressed air supply unit 40 with a simple design. In addition, a pressure-dependent actuating throttle device 22 is arranged in the vent line 20 for throttling a vent air flow 23 as needed and is configured to be actuated depending on the dryer pressure PT present in a dryer compressed air path 24 leading through the air dryer 11 between the regeneration throttle 18 and the throttle device 22. This also applies to such a configuration as shown in Fig.In the air dryer arrangement 10 illustrated in Figure 5, the aforementioned advantages of reduced noise levels can be achieved by precisely differentiating between exhaust flows 23 that require throttling and those that are less acoustically relevant. According to the illustrated embodiment, the throttling device 22 is designed as a pressure-dependent, switchable throttle valve 22' and is arranged in the vent line 20 between the air dryer 11 and the vent valve 21. The throttling device 22 is configured to be actuated when a predefined air dryer threshold pressure ps is exceeded.

[0055] Figure 5 schematically illustrates that the compressor 41 has a compressor housing 44. The regeneration line 17 has a heat transfer section 17a located inside the compressor housing 44. This allows the regeneration air 14 flowing through the regeneration line 17 to be advantageously heated in the heat transfer section 17a by waste heat from compressor components of the compressor 41, thereby increasing the water absorption capacity of the regeneration air 14.

[0056] Fig. 6 shows a schematic diagram of a vehicle 50, designed as a passenger car 50a, with a vehicle compressed air supply unit 40 and a vehicle compressed air system 51. The vehicle compressed air supply unit 40 has a compressor 41 and an air dryer assembly 10, which is configured according to one of the features described above. The compressor 41 is connected to the air dryer assembly 10 via a compressor outlet line 42 to provide compressed air 13 to be dried. The air dryer assembly 10 is connected to the vehicle compressed air system 51 via a compressed air supply line 43 to provide dried compressed air 13 to the vehicle compressed air system 51. According to the illustrated embodiment, the vehicle compressed air system 51 is configured as a sensor cleaning system for an optical sensor in the front area of ​​the vehicle 50.The vehicle 50 is characterized by a reduced noise load due to ventilation flows 23 of the vehicle compressed air supply unit 40.

[0057] Fig. 7 shows a schematic diagram of a vehicle 50 designed as a truck 50b with a vehicle compressed air supply unit 40 and a vehicle compressed air system 51. The vehicle compressed air supply unit 40 has a compressor 41 and an air dryer assembly 10, which is configured according to one of the features described above. The compressor 41 is connected to the air dryer assembly 10 via a compressor outlet line 42 to provide compressed air 13 to be dried. The air dryer assembly 10 is connected to the vehicle compressed air system 51 via a compressed air supply line 43 to provide dried compressed air 13 to the vehicle compressed air system 51. According to the illustrated embodiment, the vehicle compressed air system 51 is configured as a pneumatic braking system for the vehicle 50.Vehicle 50 is characterized by reduced noise levels due to ventilation flows 23 from the vehicle's compressed air supply unit 40. Reference symbol (part of the description).

[0058] 10 Air dryer arrangement

[0059] 11 air dryers

[0060] 12 Input connection

[0061] 13 Compressed air

[0062] 14 Regeneration air

[0063] 15 Output port

[0064] 16 Regeneration connection

[0065] 17 Regeneration line

[0066] 17a Heat transfer section

[0067] 17* Bypass line

[0068] 18 Regeneration throttle

[0069] 19 Vent connection

[0070] 20 Vent line

[0071] 21 Vent valve

[0072] 22 Throttle device

[0073] 22a Control input throttle device

[0074] 22b pneumatic control line

[0075] 22* Pressure-dependent switchable throttle valve 22" Pressure-dependent adjustable continuous valve 23 Venting airflow

[0076] 24 Dryer compressed air path

[0077] 25 Overpressure limitation

[0078] 26 Outlet check valve

[0079] 27 Diverter valve

[0080] 28 Regeneration valve

[0081] 29 Regeneration check valve

[0082] 30 Control valve

[0083] 31 Output line

[0084] 40 Vehicle compressed air supply unit 41 Compressor

[0085] 42 Compressor outlet line

[0086] 43 Compressed air supply line 44 Compressor housing

[0087] 50 vehicles

[0088] 50a Passenger cars 50b Trucks

[0089] 51 Vehicle compressed air system ps Air dryer threshold pressure PT Dryer pressure

[0090] pü Safety threshold R Regeneration operation

[0091] T drying operation

Claims

Patent claims 1. Air dryer arrangement (10) for a vehicle compressed air supply unit (40), comprising: - an air dryer (11) that can be operated in a drying mode (T) and in a regeneration mode (R), - an inlet port (12) that can be connected to or is connected to a compressor outlet line (42) for receiving compressed air (13) to be dried, - an outlet port (15) that can be connected to or is connected to a compressed air supply line (43) for supplying dried compressed air (13) to a vehicle compressed air system (51), - a regeneration connection (16) for providing regeneration air (14), wherein the regeneration connection (16) is formed by the outlet connection (15) or a regeneration connection (16) separate from the outlet connection (15), and wherein a regeneration throttle (18) is arranged in a regeneration line (17) between the regeneration connection (16) and the air dryer (11), - a vent connection (19) and a vent valve (21) arranged in a vent line (20) downstream of the air dryer (11) between the air dryer (11) and the vent connection (19) for venting the air dryer (11) and / or the vehicle compressed air system (51) as required, and - a pressure-dependent actuating throttle device (22) for throttled a venting air flow (23) in the venting line (20) as required, characterized in that the throttle device (22) is designed to be actuated depending on a dryer pressure (PT) present in a dryer compressed air path (24) leading through the air dryer (11) between the regeneration throttle (18) and the throttle device (22).

2. Air dryer arrangement (10) according to claim 1, characterized in that the throttling device (22) is configured to be actuated depending on a dryer pressure (PT) present in the air dryer (11) and / or a dryer pressure (PT) present in the vent line (20) between the air dryer (11) and the throttling device (22).

3. Air dryer arrangement (10) according to claim 2, characterized in that a control input (22a) of the throttling device (22) is directly connected to the air dryer (11), to the regeneration line (17) or to the vent line (20) of the air dryer arrangement (10) via a pneumatic control line (22b).

4. Air dryer arrangement (10) according to one of the preceding claims, characterized in that the throttling device (22) is designed as a pressure-dependent switchable throttle valve (22').

5. Air dryer arrangement (10) according to one of claims 1 to 3, characterized in that the throttling device (22) is designed as a pressure-dependent adjustable continuous valve (22").

6. Air dryer arrangement (10) according to one of the preceding claims, characterized in that the throttling device (22) is arranged in the vent line (20) downstream of the air dryer (11) between the air dryer (11) and the vent valve (21).

7. Air dryer arrangement (10) according to one of claims 1 to 5, characterized in that the throttling device (22) is arranged in the vent line (20) downstream of the air dryer (11) between the vent valve (21) and the vent connection (19).

8. Air dryer arrangement (10) according to one of the preceding claims, characterized in that the throttling device (22) is configured to be actuated when a predefined air dryer threshold pressure (ps) is exceeded.

9. Air dryer arrangement (10) according to claim 8, characterized in that the predefined air dryer threshold pressure (ps) deviates from a safety threshold (pu) of an overpressure limit (25) in the dryer compressed air path (24) and / or in the vent line (20).

10. Air dryer arrangement (10) according to claim 8 or 9, characterized in that the predefined air dryer threshold pressure (ps) is designed such that the Throttle device (22) is actuated during venting of the air dryer (11) after a temporarily completed filling of the vehicle compressed air system (51).

11. Vehicle compressed air supply unit (40) comprising a compressor (41) and an air dryer arrangement (10) according to one of the preceding claims.

12. Vehicle compressed air supply unit (40) according to claim 11, characterized in that the compressor (41) has a compressor housing (44), that the regeneration line (17) of the air dryer arrangement (10) is designed as a bypass line (17') to bypass an outlet check valve (26) of the air dryer arrangement (10), and that the regeneration line (17) has a heat transfer section (17a) which is arranged inside the compressor housing (44).

13. Vehicle (50) comprising a vehicle compressed air supply unit (40) according to one of claims 11 or 12 and a vehicle compressed air system (51).

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