Method for operating a compressed-air supply system, compressed-air supply system, and vehicle

Abstract

The invention relates to a method (1000) for operating a compressed-air supply system (DS), the method comprising the following steps: a) limiting (1100) at least one line volume (LV) connected to an outlet opening (216, 216.1, 216.2) of the at least one drying chamber (210, 210.1, 210.2) by means of a pneumatic switching arrangement (230) of a compressed-air supply installation (200); b) activating a compressor (100) for drawing in and compressing (1200) ambient air (LU) to an operating pressure (pB); c) providing (1300) the compressed air (DL) at a compressed-air connection (1), the compressed air (DL) having an operating temperature (TB); d) pressurising (1500) at least one drying chamber (210, 210.1, 210.2) with the compressed air (DL) provided at the compressed-air connection (1) until a target pressure (pZ) of the compressed air (DL) in the at least one drying chamber (210, 210.1, 210.2), which is higher than the operating pressure (pB), is reached and / or until a target temperature (TZ) of a desiccant granulate (212) located in the drying chamber, which is higher than the operating temperature (TB), is reached; e) venting (1600) the compressed air (DL) from the at least one drying chamber (210, 210.1, 210.2) to the environment (U) when the target pressure (pZ) and / or the target temperature (TZ) is reached. The invention also relates to a compressed-air supply system (DS) for carrying out the method (1000).

Description

[0001] Method for operating a compressed air supply system, compressed air supply system and vehicle

[0002] The invention relates to a method for operating a compressed air supply system, wherein the compressed air supply system comprises a compressor for providing compressed air at a compressed air connection and a compressed air supply system connected to the compressed air connection for supplying a pneumatic system connected to a compressed air supply connection, wherein the compressed air supply system comprises an air dryer unit with at least one drying chamber containing drying granules for drying compressed air guided through the drying chamber in a filling direction. The invention further relates to a compressed air supply system with which a corresponding method can be carried out and a vehicle with the same.

[0003] In vehicles, compressed air supply systems provide compressed air to pneumatic systems. For this purpose, compressed air is supplied to the compressed air supply system via the compressed air connection by a compressor. In this description, compressors are used synonymously and refer to units that compress air. Such a compressor, together with the compressed air supply system, forms a compressed air supply system. This compressed air supply system is preferably controlled by an electronic control device, for example, a control unit. A compressed air supply system, together with one or more pneumatic systems connected to it, forms a pneumatic system.

[0004] Pneumatic systems include, for example, sensor cleaning devices that use compressed air as a cleaning fluid, or air spring systems that use compressed air to inflate air springs. They all have in common that they feature multiple pneumatic switching valves to control the distribution or delivery of the compressed air supplied by the compressed air supply system. In vehicles, it is generally necessary to dry the compressed air supplied to the pneumatic system to prevent moisture in the system, thus preventing malfunctions of the pneumatic switching valves, particularly in freezing conditions.

[0005] For the provision of dried compressed air, air dryer devices are known with an air dryer unit comprising a drying granulate, which is designed to adsorb moisture from the compressed air flowing through the pneumatic main line.

[0006] The operating time of the air dryer is limited by the saturation of the drying granules within the air dryer unit. For this reason, air dryer units are usually designed as regenerative air dryer units. To regenerate such a regenerative air dryer unit, dried compressed air is passed through the unit and released to the environment via a vent line and a vent connection.

[0007] The air dryer unit has one or more drying chambers through which compressed air flows at least sequentially. A corresponding air dryer system with an air dryer unit is shown, for example, in EP 2794063 B1.

[0008] However, the availability of the air dryer unit for providing dried compressed air is limited. This poses a particular challenge in the field of autonomous driving, as the level of autonomy places increased demands on system availability and the response times of pneumatic systems, such as sensor cleaning devices. Nevertheless, sufficient drying of the compressed air, even under extreme weather conditions such as very high humidity and low temperatures, is regularly required, especially in the field of autonomous driving, to ensure vehicle safety.

[0009] The invention addresses this point, aiming to improve the efficiency of regenerating air dryer units with at least one drying chamber containing drying granules. The invention solves this problem in a first aspect by a method according to claim 1. The method comprises the following steps:

[0010] a) Limiting at least one conduit volume connected to an outlet opening of the at least one drying chamber by means of a pneumatic switching arrangement of the air dryer device,

[0011] b) Activating the compressor to draw in and compress ambient air to an operating pressure,

[0012] c) Providing the compressed air at the compressed air connection, wherein the compressed air has an operating temperature,

[0013] d) Pressurizing the at least one drying chamber with the compressed air supplied at the compressed air connection until a target pressure of the compressed air in the at least one drying chamber is reached, which is higher than the operating pressure, and / or until a target temperature is reached in the at least one drying chamber, which is higher than the operating temperature,

[0014] e) Venting the compressed air from the at least one drying chamber into the environment when the target pressure and / or target temperature is reached.

[0015] The inventors advantageously recognized that, as a result of supplying the at least one drying chamber with compressed air in conjunction with limiting the volume of the pipe connected to the drying chamber, a pressure increase occurs in the drying chamber.

[0016] By compressing the compressed air to the target pressure, which is higher than the operating pressure, the water content of the compressed air increases, and the dew point temperature rises. The dew point temperature is the temperature at which the moisture contained in a volume of air condenses. Simultaneously, the compression of the compressed air leads to an increase in the gas temperature within the air dryer unit. This temperature increase depends on the polytropic exponent and the compression ratio. The water absorption capacity of the compressed air increases significantly with the gas temperature, or conversely, its relative humidity decreases. Thus, by compressing the compressed air, both the dew point temperature rises and the gas temperature within the air dryer unit rises to the target temperature, thereby increasing the air's water absorption capacity.With the polytropic exponents applicable to typical compressors, the temperature-related increase in water absorption capacity due to the rising gas temperature in the air dryer unit exceeds the compression-related increase in absolute humidity in the compressed gas. It follows that the increase in gas temperature in the air dryer unit associated with the corresponding compression allows the compressed air to be suitable for regenerating the air dryer unit, despite the compression-related increase in absolute humidity. Typical values ​​for the polytropic exponents range from 1.15 to 1.25, with the polytropic exponent increasing as the compressor heats up. Because the compressed air in the air dryer unit is compressed to a target pressure higher than the operating pressure, this is accompanied, in particular, by a temperature increase to a target temperature.The water absorption capacity of the compressed air upon reaching the target temperature, resulting from the pressure increase to the target pressure, enables the regeneration of the drying granules in the drying chamber even without additional drying of the compressed air by the air dryer unit. This allows for the regeneration of the drying granules, particularly in open pneumatic systems such as compressed air supply systems with sensor cleaning devices. However, a similar effect can also be achieved simply by supplying the air dryer unit with compressed air until the target temperature is reached—that is, regardless of the target pressure. This can be accomplished, for example, by operating the compressor for a very long time.

[0017] A pneumatic switching arrangement according to the invention relates to one or more pneumatic switching elements that can be actuated electrically, pneumatically or automatically and are designed to control compressed air flows in pneumatic lines.

[0018] Further developments of the invention are specified in the dependent claims, which further develop the concept of the invention with regard to advantageous features within the scope of the problem statement and with regard to further advantages.

[0019] Preferably, an inlet opening of the drying chamber is supplied with compressed air, particularly directly via the compressed air connection, without prior drying of the compressed air. Preferably, the pneumatic switching arrangement includes at least one pressure limiting valve located between the outlet opening of the at least one drying chamber and the compressed air supply connection. Venting the compressed air from the at least one drying chamber preferably comprises the following step:

[0020] Opening of the pressure relief valve when an opening pressure is exceeded in at least one drying chamber.

[0021] A suitable pressure relief valve effectively prevents other pneumatic valves in the compressed air supply system or a connected pneumatic system from being unintentionally opened due to pressure increases in the line volume. This prevents damage to the compressed air supply system or the connected pneumatic system. The pressure relief valve is preferably a self-opening check valve that opens against spring force or an actively controlled valve. The target pressure in the drying chamber can be defined by the design of the pressure relief valve and, in particular, the associated opening pressure. Positioning the pressure relief valve between an outlet opening of the drying chamber and the compressed air supply connection ensures that no moist compressed air from the drying chamber enters the pneumatic system via the compressed air connection.

[0022] Preferably, the pneumatic switching arrangement comprises at least one venting valve, which is arranged between the outlet opening of the at least one drying chamber and a venting connection of the compressed air supply system. More preferably, the venting of the compressed air from the at least one drying chamber comprises the following step:

[0023] Controlling the vent valve to switch to a release position and release the line volume upon reaching the target pressure and / or target temperature, wherein the at least one vent valve is designed such that a pressure drop occurs when the compressed air is vented from the at least one drying chamber via the vent valve, in particular a pressure drop of at least 30%, most preferably at least -80%. In particular, the pressure drop occurs in < 2 seconds. A pressure drop of at least 80% is required to vent the compressed air, heated to the target temperature and saturated with water absorption.

[0024] The reduced water absorption capacity of the drying granules, due to the increased pressure in the drying chamber at elevated temperatures, leads to increased condensation of water, a process known as "sweating." This results in thermal regeneration of the drying granules as a consequence of the increased temperatures in the drying chamber. This regeneration is further supported by the compressed air circulated through the air dryer unit. The condensed water separated from the drying granules can be expelled from the drying chamber, particularly by a sudden pressure drop when the vent valve opens. The necessary pressure drop for this is at least 30%, especially within 2 seconds.

[0025] The target pressure is preferably lower than the opening pressure, in particular at least 2% lower, and most preferably at least 30% lower. Because the target pressure is lower than the opening pressure, no compressed air is released from the line volume via the compressed air relief valve. The sudden opening of the vent valve thus leads, due to the pressure drop of at least 30%, to a sudden expulsion of the condensed water from the drying chamber.

[0026] Alternatively, the target pressure preferably corresponds to at least the opening pressure, with the compressor remaining activated for a predefined period after the pressure relief valve opens. The pressure relief valve is designed such that when the compressed air is vented from the at least one drying chamber via the pressure relief valve, an initial pressure drop of a maximum of 5% occurs. Preferably, the target pressure in the drying chamber is monitored by a pressure sensor. In particular, the pressure in the drying chamber is measured directly for this purpose. Alternatively, the pressure in the drying chamber can be derived from the compressor's operating time. It should be understood that a pressure drop occurs after the target pressure is reached. When the air dryer unit is completely vented at the end of the regeneration process, the pressure drop is, in particular, at least 80%.The increasing internal pressure of the dryer, which rises until the target pressure is reached, causes the pressure relief valve to open at a certain point. This occurs when the opening pressure of the pressure relief valve is reached. The fact that only a very small pressure drop of a maximum of 5% occurs when the compressed air is vented from at least one drying chamber via the pressure relief valve is achieved by appropriately sized valves. The temperature of the compressed air in the drying chamber thus continues to rise due to the continuous operation of the compressor, even with a limited pipe volume. Therefore, even without a further pressure increase, the temperature of the compressed air in the drying chamber can be continuously increased, thereby increasing its water absorption capacity.

[0027] In preferred embodiments, the vent valve is switched to the release position only after the target temperature has been reached. The vent valve advantageously has a larger nominal diameter than the pressure relief valve. Thus, when the vent valve is switched to the release position, accumulated moisture is blown out of the air dryer unit with a pressure drop of preferably at least 80%. The process is advantageously such that the compressor initially operates against the pressure relief valve, thereby increasing the gas temperatures and enabling regeneration. As the temperature of the drying granules continues to rise, liquid water is released, which is then blown out via the vent valve in a final venting process.

[0028] Preferably, the compressor is a multi-stage compressor and has at least one low-pressure stage with a first stage inlet for drawing in and compressing compressed air from the environment and a high-pressure stage with a second stage inlet for supplying compressed compressed air at the operating pressure. The method preferably further comprises the following steps:

[0029] Returning the compressed air from the compressed air connection to the second stage inlet of the high-pressure stage of the compressor until a supply temperature of the compressed air supplied at the compressed air connection is reached and / or until a predefined lead time has elapsed,

[0030] The compressed air supplied at the compressed air connection is passed through at least one drying chamber at the supply temperature. By returning the already compressed compressed air to the stage inlet of the high-pressure stage, the temperature of the compressed air supplied at the compressed air connection is continuously increased. This pre-flow process, in which the compressed air is recirculated back to the inlet of the high-pressure stage, results in a steady temperature increase depending on the compressor's operating time. This temperature increase increases the water absorption capacity of the compressed air supplied for regenerating the air dryer unit. Alternatively or additionally, the compressed air can also be returned only after passing through the air dryer unit, i.e., from the outlet of the at least one drying chamber back to the second stage inlet of the high-pressure stage of the compressor.Thus, the drying granules are additionally heated by passing through the air dryer unit.

[0031] Preferably, ambient air is drawn in by the compressor until an initial fill level of an inlet line volume is reached upstream of the at least one drying chamber in the filling direction. Subsequently, only the recirculated compressed air is compressed by the compressor until the supply temperature is reached and / or until the predefined pre-run time has elapsed. The efficiency of the temperature increase is thus increased by recirculating the already compressed compressed air to the stage inlet of the high-pressure stage.

[0032] Preferably, the method further includes switching the vent valve to the release position after a predefined time period. Thus, after a corresponding temperature increase resulting from the continuous operation of the compressor for the predefined period, the compressed air can subsequently be vented to the environment via the vent valve. After the predefined time period has elapsed, it is therefore ensured that the compressed air, due to the temperature increase, has a sufficient water absorption capacity to regenerate the drying granules.

[0033] The method preferably further comprises monitoring the temperature of the drying granules in the at least one drying chamber. The temperature of the drying granules can preferably be monitored using a temperature sensor. The monitored temperature is compared with the target temperature. Alternatively or additionally, the target temperature is monitored by deriving it from the compressor runtime and the ambient temperature. The method further preferably comprises monitoring the supply temperature of the compressed air. This monitoring is preferably carried out using a temperature sensor or is derived from the compressor runtime and the ambient temperature.

[0034] Thus, depending on the monitored target temperature, the compressed air from at least one drying chamber can be vented into the environment.

[0035] Furthermore, the method preferably includes monitoring the pressure of the compressed air in the at least one drying chamber. The pressure is preferably monitored by a pressure sensor assigned to the at least one drying chamber. The monitored pressure is compared with the target pressure. Alternatively, the pressure in the drying chamber is derived from the compressor runtime and the line volume, and the achievement of the target pressure is thus determined.

[0036] Preferably, the method further comprises monitoring the saturation of the drying granules to identify the need for regeneration of the at least one drying chamber. Monitoring the saturation of the drying granules can preferably be carried out by modeling the amount of water stored in the drying granules, taking into account the compressor runtime and speed.

[0037] Preferably, the method further comprises monitoring the humidity of the ambient air. Steps a) to e) are performed when the saturation exceeds a maximum limit and the humidity is below a (first) humidity limit. Alternatively or additionally, steps a) to e) are performed when the saturation exceeds a minimum saturation limit and the humidity is below a second humidity limit, which is lower than the first. Steps a) to e) for increasing the efficiency of the drying granule regeneration are thus preferably performed in cases where the saturation of the air dryer necessitates the timely regeneration of the drying granules. This is the case when the saturation approaches the maximum saturation limit.As a further prerequisite for carrying out steps a) to e), the humidity of the ambient air is taken into account, since even if the ambient air is compressed to the target pressure and has the target temperature, it can only bind sufficient moisture from the drying granules if its humidity is below the (first) humidity limit. It should be understood that the saturation limit does not necessarily describe the theoretically possible maximum water absorption capacity of the drying granules, but rather a defined value below this maximum capacity. Therefore, a residual water absorption capacity always remains, even when the saturation limit is reached. Overall, a suitable saturation limit can preferably be selected depending on the humidity of the ambient air.This approach need not be limited to comparing two moisture contents, but can be extended to a linear saturation function. Considering absolute humidity (g / m³) is particularly advantageous. 3 ) of the ambient air. The less water is bound in the ambient air, the more can be removed from the dryer.

[0038] Alternatively or additionally, steps a) to e) are performed to increase the efficiency of regeneration if the saturation exceeds the minimum limit. This means that at least a minimum saturation of the drying granules exists, which can be eliminated by regeneration, and at the same time the humidity of the ambient air is particularly low, i.e., below the first humidity limit. Therefore, even if there is no immediate need to regenerate the drying granules, the air dryer can be regenerated using steps a) to e) in the case of very dry ambient air.

[0039] Preferably, the target temperature is at least 60 °C, in particular at least 90 °C. Alternatively or additionally, the target pressure is at least 18 bar, in particular at least 20 bar. Alternatively or additionally, the flow temperature is at least 60 °C, in particular at least 90 °C.

[0040] According to a preferred embodiment, the drying chamber is a primary drying chamber, and the air dryer unit further comprises a secondary drying chamber. At least steps a) to e) are selectively performed for the partial regeneration of only the primary drying chamber and / or only the secondary drying chamber, and for the simultaneous regeneration of both the primary and secondary drying chambers. By providing two drying chambers, which can be operated both serially and—at least with respect to the primary drying chamber—individually, the dryer bed can be extended as needed by sequentially passing through both drying chambers. In cases where a lower drying capacity is sufficient, only one of the drying chambers can be operated in individual flow mode.Similarly, only one of the drying chambers can be regenerated by including steps a) to e), or simultaneous regeneration can be achieved by a serial flow through both drying chambers.

[0041] Preferably, the compressed air supply system further comprises a reservoir connected to the compressed air supply connection, which is designed to store dried compressed air at the operating pressure for filling a pneumatic system. The method preferably includes the following steps:

[0042] Filling the reservoir with dried compressed air at a second target pressure that is higher than the operating pressure,

[0043] Guiding the compressed air at the second target pressure against the filling direction through at least one drying chamber.

[0044] By filling the reservoir with compressed air at a second target pressure, which is above the operating pressure—that is, the filling pressure required to fill the pneumatic system—a larger quantity of compressed air is stored in the reservoir. Furthermore, the stored compressed air has a higher temperature due to compression. Simultaneously, the increased compressor runtime resulting from the higher pressure applied to the reservoir also leads to a temperature increase in the compressed air and the dryer assembly. During the regeneration of the air dryer unit, the compressed air with its elevated gas temperature can thus adsorb a greater amount of moisture from the drying granules, further increasing the efficiency of the air dryer unit's regeneration process.Because the reservoir contains a higher volume of compressed air when filled with compressed air that has been compressed to the second target pressure, its operational readiness is ensured even after regeneration. Preferably, only the excess volume of compressed air stored in the reservoir, compared to the volume when filled to operating pressure, is used to regenerate the air dryer unit. The invention solves the aforementioned problem in a second aspect by providing a compressed air supply system for a vehicle, in particular a passenger car, according to claim 13. The compressed air supply system comprises a compressed air supply unit for providing compressed air.

[0045] a compressed air connection for connection to a compressor,

[0046] a compressed air supply connection for connecting a pneumatic system, a pneumatic main line for conveying compressed air from the compressed air connection to the compressed air supply connection in one filling direction,

[0047] an air dryer unit arranged in the pneumatic main line for drying the compressed air guided in the filling direction,

[0048] a throttle arranged in the pneumatic main line downstream of the air dryer unit in the filling direction, and

[0049] The compressed air supply system comprises a vent line branching off from the pneumatic main line between the air dryer unit and the compressed air connection, leading to a vent connection. Furthermore, the system includes a compressor for providing compressed air to the compressed air supply system at the compressed air connection and a control device connected to the compressed air supply system and the compressor via a signal conductor. According to the second aspect, the invention proposes a pneumatic switching arrangement to solve the aforementioned problem. This arrangement is configured to limit at least one line volume connected to an outlet opening of the at least one drying chamber, and the control device is configured to carry out a method according to the first aspect of the invention.

[0050] Through a suitable pneumatic switching arrangement and the control device configured to carry out the method according to the first aspect of the invention, the compressed air supply system benefits from the advantages mentioned in relation to the first aspect of the invention. Advantages and preferred embodiments according to the first aspect of the invention are likewise advantages and preferred embodiments according to the second aspect of the invention, and vice versa.

[0051] Preferably, the pressure relief valve is designed to release compressed air from the air dryer unit without a pressure drop greater than 5% when the compressor is activated. More preferably, the compressor is a multi-stage compressor and has at least one low-pressure stage with a first stage inlet for drawing compressed air from the environment and a high-pressure stage with a second stage inlet for supplying compressed air at the operating pressure. The compressed air supply system further comprises a return line connecting the compressed air connection to the second stage inlet and a return switching valve arranged in the return line, which is configured to selectively close and open the return line.Thus, by means of a suitable return line and a return switching valve located within it, the compressed air can be recirculated in a pre-run operation back to the second stage inlet, so that the compressed air is continuously heated. Alternatively or additionally, the return line connects an outlet opening of at least one drying chamber to the second stage inlet of the high-pressure stage of the compressor. In this case, the compressed air is only returned after passing through the air dryer unit, i.e., from the outlet opening of at least one drying chamber to the second stage inlet of the high-pressure stage of the compressor. Thus, the drying granules are additionally heated by passing through the air dryer unit.

[0052] Preferably, the drying chamber is a primary drying chamber and the air dryer unit further comprises a secondary drying chamber. In this case, the control device is configured to selectively carry out the method according to the first aspect of the invention only for regenerating the primary drying chamber or the secondary drying chamber, and also for simultaneously regenerating the primary drying chamber and the secondary drying chamber.

[0053] The compressed air supply system preferably further comprises a bypass line which branches off from the main pneumatic line upstream of the air dryer unit in the filling direction and reconnects to the main pneumatic line downstream of the air dryer unit and is connected to the vent line.

[0054] To solve the aforementioned problem, the invention proposes, in a third aspect, a vehicle, in particular a passenger car, comprising a compressed air supply system according to the second aspect of the invention and a pneumatic system connected to the compressed air supply port of the compressed air supply system for receiving dried compressed air. By means of such a compressed air supply system, the vehicle benefits from the advantages described in relation to the first and second aspects of the invention. Advantages and preferred embodiments according to the first and second aspects of the invention are therefore also advantages and preferred embodiments according to the third aspect of the invention, and vice versa.

[0055] Embodiments of the invention are now described below with reference to the drawings and to the prior art, some of which is also shown. These drawings are not necessarily to scale; rather, where explanatory, they are presented in a schematic and / or slightly distorted form. For further information on the teachings directly apparent from the drawings, reference is made to the relevant prior art. It should be noted that numerous modifications and changes concerning the form and details of an embodiment can be made without deviating from the general idea of ​​the invention. The features of the invention disclosed in the description, the drawings, and the claims can be essential for the further development of the invention, both individually and in any combination.Furthermore, the invention encompasses all combinations of at least two of the features disclosed in the description, the drawing, and / or the claims. The general idea of ​​the invention is not limited to the exact shape or detail of the preferred embodiment shown and described below, nor is it limited to an object that would be restricted compared to the object claimed in the claims. For specified dimensioning ranges, values ​​lying within the stated limits are also disclosed as limit values ​​and may be used and claimed as desired.

[0056] Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

[0057] FIG. 1 : a vehicle with a pneumatic system according to a preferred embodiment;

[0058] FIG. 2: a pneumatic system with a compressed air supply system according to a preferred embodiment; FIG. 3: a compressed air supply system in a first preferred embodiment for a pneumatic system according to FIG. 2;

[0059] FIG. 4a: a compressed air supply system according to a second preferred embodiment for a pneumatic system according to FIG. 2 in a first switching position;

[0060] FIG. 4b: the compressed air supply system according to FIG. 4a in a second switching position;

[0061] FIG. 5: a compressed air supply system according to a third preferred embodiment for a pneumatic system according to FIG. 2;

[0062] FIG. 6: a compressed air supply system according to a fourth preferred embodiment for a pneumatic system according to FIG. 2;

[0063] FIG. 7: an air dryer device of a compressed air supply system according to FIG. 3 to FIG. 6; and

[0064] FIG: 8: a method for operating a pneumatic system according to FIG. 3 to FIG. 6.

[0065] FIG. 1 shows a schematic representation of a vehicle FZ. The vehicle FZ is, in particular, a passenger car P, which includes a pneumatic system PS and a control unit ECU. The control unit ECU is configured to control the pneumatic system PS.

[0066] FIG. 2 shows an exemplary pneumatic system PS with a compressed air supply system DS comprising a compressor 100 and a compressed air supply system 200, and with a pneumatic system 300 connected to the compressed air supply system DS.

[0067] The compressor 100 is equipped with an intake port 0 for drawing compressed air DL from the environment via an intake line 10 in which an air filter 0.1 is arranged. The compressor 100 comprises a reciprocating piston unit 110 and an electric motor 120 for driving the reciprocating piston unit. The compressor 100 is configured to supply the compressed air DL, compressed by the reciprocating piston unit 110, to a compressed air connection 1. The compressed air supply system 200 is connected to the compressed air connection 1 to receive the compressed compressed air DL.

[0068] The compressed air supply system 200 has, in addition to compressed air connection 1, a compressed air supply connection 2, to which the pneumatic system 300 is connected for receiving compressed air DL. A pneumatic main line 21 extends between compressed air connection 1 and compressed air supply connection 2, through which compressed air DL is guided in a filling direction B to the compressed air supply connection 2. An air dryer unit LT with an air dryer unit LE is arranged in the pneumatic main line 21, which is configured to dry the compressed air DL guided through the pneumatic main line 21.

[0069] Furthermore, the compressed air supply system 200 preferably includes a vent connection 3 through which compressed air DL can be released to the environment U. A vent line 13 branches off from the pneumatic main line 21 between the compressed air connection 1 and the air dryer unit LT and extends to the vent connection 3. A throttle D is also arranged between the air dryer unit LT and the compressed air supply connection 2.

[0070] The compressed air supply system 200 also includes a venting valve arrangement EV, which is designed for the selective release of the venting line 13.

[0071] The venting valve assembly EV comprises a venting valve EV1, which is designed here as a pneumatically actuated 2 / 2-way valve and is arranged in the venting line 13. Furthermore, the venting valve assembly EV comprises a pilot valve SEV2, to which a pilot pressure line 14 is assigned, which connects to the pneumatic main line 21 between the throttle D and the compressed air supply connection 2. The pilot valve EV2 is configured to apply a pilot pressure pS to the venting valve EV1 by supplying compressed air DL from the pneumatic main line 21, in order to move it from the switching position shown in FIG. 2 to a release position in which the venting line 13 can be pneumatically traversed in a venting direction E, so that compressed air DL can be discharged to the environment U via the venting port 3.Furthermore, the pilot valve SEV2 is assigned a valve vent line 15, through which compressed air DL with the control pressure pS, which was used to actuate the vent valve EV1, can be vented into the environment U.

[0072] To vent the pneumatic system 300, compressed air DL is directed in a venting direction E, i.e., counterflow G against the filling direction B, from the compressed air supply connection 2 into the pneumatic main line 21 and first flows through the throttle D. The throttle D expands the compressed air DL flowing in venting direction E and thus reduces its relative humidity before the compressed air DL flows into the air dryer unit LT. In the air dryer unit LT, the dry compressed air DL flowing in venting direction E absorbs some of the moisture bound in a drying granulate (see FIG. 3 and FIG. 4).

[0073] The compressed air DL returned in the venting direction E is then released to the environment U via the venting line 13.

[0074] The pneumatic system 300 is preferably a sensor cleaning unit 301 or a level control device 302. In the case of a sensor cleaning device 301, compressed air DL for regenerating the air dryer unit LE does not flow back from the actuators of the sensor cleaning device 301 itself, but can, for example, be supplied by a separately filled reservoir. Furthermore, separate piping arrangements of the compressed air supply system 200 or the pneumatic system 300 are possible for returning dried compressed air DL to the main pneumatic line 21 in counterflow G. Corresponding arrangements are shown, for example, in the German patent applications with the application numbers 102023 119 856.4, 102023 119858.0, 102023 119855.6, 102023 119857.2 and 102023 119 859.9.

[0075] In a level control system 302, dried compressed air DL is returned to the compressed air supply system 200 in the venting direction E for, for example, air spring bellows (not shown). A reservoir 500 is preferably connected to the compressed air supply connection 2. The reservoir 500 is preferably connected to the compressed air supply connection 2 via a common gallery line with the pneumatic system 300 as the pneumatic consumer. The reservoir 500 is configured to be filled with dried compressed air DL via the compressed air supply connection 2 from the compressed air supply system 200. Furthermore, the reservoir 500 is configured to provide dried compressed air DL for regenerating the air dryer unit LE, which is passed through the air dryer unit LE in counterflow G and can be discharged to the environment U via the vent connection 3.

[0076] FIG. 3 shows a preferred embodiment of the compressed air supply system DS. The compressed air supply system DS comprises a compressor 100 and a compressed air supply unit 200 connected to the compressor 100, including an air dryer unit LT. Identical or similar components have identical reference numerals in FIG. 2 and FIG. 3, and reference is made to the description of the compressed air supply system DS according to FIG. 2.

[0077] The air dryer device LT comprises an air dryer unit LE with at least one drying chamber 210, which is filled with drying granules 212 (see FIG. 7). A section of the pneumatic main line 21 flowing upwards from the drying chamber 210 in the filling direction B forms an inlet line volume LVE.

[0078] As shown in FIG. 3, the drying chamber 210 preferably has an inlet opening 215 and an outlet opening 216.

[0079] The air dryer unit LT further comprises a compressor connection 1.1 for connection to the compressor 100 or the compressed air connection 1, a supply connection 2.1 for connection to the pneumatic main line 21 and for supplying compressed air DL to the compressed air supply connection 2, and a vent connection 3.1. The vent connection 3.1 is designed for connection to the vent line 13 (see FIG. 2). Compressed air DL from the compressor 100 is thus received via the compressor connection 1.1 for filling a pneumatic system 300 (see FIG. 2). This compressed air DL is passed through at least the primary drying chamber 210 for drying and is made available at the supply connection 2.1 for supplying the pneumatic system 300 via the compressed air supply connection 2. For regeneration of the air dryer unit LE, dry compressed air DL can be supplied to supply connection 2.1 provided and guided in counterflow G through the drying chamber 210 and directed in venting direction E (see FIG. 2) via the venting line connection 3.1 into the venting line 13 (see FIG. 2) and discharged to the environment U via the venting connection 3.

[0080] Furthermore, the compressed air supply system DS, in particular the compressed air supply system 200, includes a pneumatic switching arrangement 230, which is designed to limit at least one line volume LV connected with an outlet opening 216 of the at least one drying chamber 210.

[0081] The pneumatic switching arrangement 230 comprises a pressure relief valve 251, which is arranged between the outlet opening 216 of the at least one drying chamber 210 and the compressed air supply connection 2, in particular a supply connection 2.1 of the air dryer unit LT. The pressure relief valve 251 is configured to open when an opening pressure pO in the at least one drying chamber 210 is exceeded and to release compressed air DL from the drying chamber 210.

[0082] Furthermore, the compressed air supply system DS, in particular the compressed air supply system 200, includes a bypass line 22, which is designed to connect the compressor connection 1.1 to a supply connection 2.1 of the air dryer unit LT, bypassing the air dryer unit LE.

[0083] The bypass line 22 branches off from the pneumatic main line 21 at a second branch point Z between the compressor connection 1.1 and a drying chamber 210 of the air dryer unit LE and connects to the pneumatic main line 21 at a connection point AN between the drying chamber 210 and the supply connection 2.1.

[0084] It is further preferred that the air dryer LT comprises sensors 240 for detecting operating parameters S. These operating parameters S are preferably provided to the control unit ECU (see FIG. 1) and include, for example, a temperature ST, a pressure SP, a humidity SH, or a dew point Sp of either the compressed air DL within the compressed air supply system 200 or the ambient air LU. The control unit ECU is then configured to provide control signals Sv for controlling the compressed air supply system 200 based on the detected operating parameters S. The exact control functions and the processing of the operating parameters S are explained in connection with the method according to FIG. 8.

[0085] Preferably, a throttle valve 30 is arranged between the supply port 2.1 and the compressed air supply port 2, which is designed to throttle the compressed air DL provided at the compressed air port 2 according to the requirements of a connected pneumatic system 300 (see FIG. 2).

[0086] FIGS. 4a and 4b show another preferred embodiment of the compressed air supply system DS. Identical or similar components have identical reference numerals in FIGS. 3 and 4, and reference is made to the description of the previous embodiment according to FIG. 3, with only differences being discussed.

[0087] The compressor 100 is a multi-stage compressor and, in the illustrated embodiment, has a low-pressure stage 110.1 and a high-pressure stage 110.2. The compressor 100 draws compressed air DL from the environment U via the intake port 0 through a first stage inlet 110.1a of the low-pressure stage 110.1. In the low-pressure stage 110.1, the compressed air DL is pre-compressed and supplied to the high-pressure stage 110.2 via a second stage inlet 110.2a. The high-pressure stage 110.2 compresses the compressed air DL to the operating pressure pB.

[0088] The compressed air supply system DS, in particular the compressed air supply unit 200, further comprises a return line 24, which branches off from the pneumatic main line 21 between the compressed air connection 1 and the at least one drying chamber 210 and connects to the stage inlet 110.2a of the high-pressure stage 110.2. Alternatively, the return line can also branch off between the at least one drying chamber and the supply connection 2.1 (not shown in Fig. 4a). This arrangement allows the drying granules 212 to be heated during recirculation. The compressed air supply unit 200 also comprises a pneumatic return switching arrangement 225, which is configured, in a first switching position ST1 as shown in Fig. 4a, to connect the compressed air connection 1 to the second stage inlet 110.2A of the high-pressure stage 110.2 via the return line 24.The compressed air DL supplied at the compressed air connection 1 is thus returned to the high-pressure stage 110.2 of the compressor 100 via the return line 24 before passing through the drying chamber 210. Due to the continuous operation of the compressor 100 and the return of the compressed and thus heated compressed air DL to the second stage inlet 110.2a of the high-pressure stage 110.2, the compressed air DL is continuously heated. The return switching arrangement 224 includes a return switching valve 225 for this purpose, which is shown here in the first switching position ST1. Furthermore, a return check valve 226 is arranged in the return line 24, which is also associated with the return switching arrangement 225. The return check valve 226 prevents compressed air DL from flowing back from the return line 24 into the pneumatic main line 21.

[0089] In the second switching position ST2 shown in FIG. 4b, the return switching arrangement 224, and in particular the return switching valve 225, is configured to connect the compressed air connection 1 to the drying chamber 210, and especially to its inlet opening 215. The return switching arrangement 224 switches to the second switching position ST2, in particular after a predefined pre-run time TV has elapsed or when the compressed air DL supplied at the compressed air connection 1 has reached a pre-run temperature. The compressed air DL, heated to the pre-run temperature, then flows through the drying chamber 210 and, due to the increased temperature, can bind a greater amount of moisture, thus optimizing the regeneration of the drying granules 212 (see FIG. 7) in the drying chamber 210.

[0090] FIG. 5 shows another preferred embodiment of the compressed air supply system DS. Identical or similar components have identical reference numerals, and reference is made to the detailed description of the embodiment according to FIG. 3 and FIG. 4, where only the differences between the two embodiments are discussed.

[0091] The air dryer unit LE comprises a plurality of drying chambers 210 filled with a drying granulate filling 212 (see FIG. 7). A primary drying chamber 210.1 and a secondary drying chamber 210.2 are shown here. Further drying chambers may be present.

[0092] As shown in FIG. 5, the primary drying chamber 210.1 preferably has a primary outlet opening 216.1 and a primary inlet opening 215.1. The secondary drying chamber 210.2 has a secondary outlet opening 216.2 and a secondary inlet opening 215.2.

[0093] The primary drying chamber 210.1 can be individually supplied with compressed air DL, with the primary inlet opening 215.1 being connected to the compressor connection 1.1 via a primary inlet path 211.1. Furthermore, the secondary drying chamber 210.2 can preferably also be individually supplied with compressed air DL, and the secondary inlet opening 215.2 is connected to the compressor connection 1.1 via a secondary inlet path 211.2.

[0094] The primary drying chamber 210.1 is connected to the vent connection 3 and, in particular, the vent line 13 (see FIG. 2) via a primary vent path 13.1 and a first vent line connection 3.1. The secondary drying chamber 210.2 is connected to the vent connection 3 and, in particular, the vent line 13 (see FIG. 2) via a secondary vent path 13.2 and a second vent line connection 3.2. However, in order for the secondary drying chamber 210.2 to be regenerated individually, a further switching valve would have to be provided in the second main line section 21 B to selectively shut off the pneumatic main line 21 in this area.

[0095] Furthermore, a bypass line 22 and a bypass connection line 22B, as well as a bypass throttle D2 in the bypass connection line 22B, are provided. The bypass line 22 is designed to connect the compressor connection 1.1 to the supply connection 2.1, bypassing the primary drying chamber 210.1 and the secondary drying chamber 210.2. The bypass connection line 22B connects the pneumatic main line 21 and the bypass line 22, with the bypass connection line 22B branching off from the pneumatic main line 21 between the primary drying chamber 210.1 and the secondary drying chamber 210.2 at a first branch point Z1 and connecting to the bypass line 22 at a first connection point A1. The bypass line 22 branches off at a second branch point Z2 between the compressor connection 1.1 and the primary drying chamber 210.1 from the pneumatic main line 21 and connects to the pneumatic main line 21 at a second connection point A2 between the secondary drying chamber 210.2 and the supply connection 2.1.

[0096] The primary inlet path 211.1 is preferably assigned at least the first pneumatic main line section 21 A. The first pneumatic main line section 21 A extends from the compressor connection 1.1 to the first inlet opening 215.1.

[0097] The secondary inlet path 211.2 preferably includes a portion of the bypass line 22, namely a first bypass section 22A extending between the second branch point Z2 and the first connection point A1, as well as the bypass connection line 22B. Furthermore, the secondary inlet path includes a third pneumatic main line section 21C extending between the first branch point Z1 and the secondary inlet opening 215.2 of the secondary drying chamber 210.2. The bypass line 22 also comprises a second bypass section 22C extending from the first connection point A1 to the supply connection 2.1.

[0098] The pneumatic switching arrangement 230 is furthermore designed to control the distribution of compressed air DL and the pressurization of the individual drying chambers 210.1, 210.2 or multiple drying chambers.

[0099] The pneumatic switching arrangement 230, not shown in Fig. 5, preferably comprises a first bypass switching valve 232, a second bypass switching valve 237, a primary air dryer protection valve 238, and a secondary air dryer protection valve 231. In particular, the second bypass switching valve 237 is required for the distribution of compressed air DL.

[0100] The bypass switching valve 232 is configured to selectively connect the secondary inlet path 211.2 to the bypass line 22B. The secondary air dryer protection valve 231 is configured to selectively block and release the secondary inlet path 211.2. Furthermore, the bypass switching valve 232 is configured to selectively connect the primary drying chamber 210.1 to the supply port 2.1.

[0101] The primary drying chamber 210.1 is associated with the primary air dryer protection valve 238, which is designed to selectively block and release the primary inlet path 211.1. The primary air dryer protection valve 238 is located in the first pneumatic main line section 21 A between the compressor connection 1.1 and the primary drying chamber 210.1.

[0102] The secondary air dryer protection valve 231 is configured analogously to the selective blocking and releasing of the secondary inlet path 211.2 and is arranged between the compressor connection 1.1 and the secondary drying chamber 210.2. The secondary air dryer protection valve 231 is specifically located in the third pneumatic main line section 21 C, i.e., between the first branch point Z1 and the secondary drying chamber 210.2.

[0103] The secondary air dryer protection valve 231 is preferably designed as a 2 / 2-way valve 235.

[0104] The bypass switching valve 232 is a first bypass switching valve 232, and the pneumatic switching arrangement 230 further comprises a second bypass switching valve 237, which is arranged in the bypass line 22, in particular in the first bypass section 22A. The second bypass switching valve 237 is configured for selectively blocking and releasing the bypass line 22, such that, if required, undried compressed air DL can be routed from the compressor connection 1.1 to the supply connection 2.1 via the bypass line 22.

[0105] FIG. 6 shows another embodiment of the compressed air supply system DS, and FIG. 7 shows a detailed section of the compressed air supply system DS according to FIG. 6. Identical or similar components have identical reference numerals, and reference is made to the detailed description of the compressed air supply system DS according to FIG. 5, where only the differences between the two embodiments are discussed. The bypass switching valve 232 is designed as a 2 / 3-way valve 236 in FIG. 6. In this case, the secondary air dryer protection valve 231, which connects the primary drying chamber 210.1 and the secondary drying chamber 210.2 as needed, can be omitted.

[0106] As shown in FIG. 7, the primary drying chamber 210.1 preferably has the primary outlet opening 216.1 on a first end face 213 and the primary inlet opening 215.1 on a second end face 214. The secondary drying chamber 210.2 has the secondary inlet opening 215.2 on the first end face 213 and the secondary outlet opening 216.2 on the second end face 214.

[0107] The primary drying chamber 210.1 can be individually supplied with compressed air DL, with the primary inlet opening 215.1 being connected to the compressor connection 1.1 via a primary inlet path 211.1. Furthermore, the secondary drying chamber 210.2 is preferably also supplied with compressed air DL, and the secondary inlet opening 215.2 is connected to the compressor connection 1.1 via a secondary inlet path 211.2.

[0108] Preferably, a secondary non-return valve 233 is optionally provided between the secondary drying chamber 210.2 and the supply connection 2.1.

[0109] As further shown in FIG. 7, a plurality of drying chambers 210 is preferably configured as a plurality of tubes 217 with at least a first tube 217a and a second tube 217b. The plurality of drying chambers 210 extends in the axial direction A, and the primary drying chamber 210.1 and the secondary drying chamber 210.2 shown here are arranged adjacent to each other in the radial direction R.

[0110] FIG. 8 shows a method 1000 for operating a compressed air supply system DS as shown in FIG. 2 to FIG. 6. Reference is made to the compressed air supply systems DS according to FIG. 2 to FIG. 6.

[0111] Method 1000 comprises, in a first step 1100, limiting at least the line volume LV connected to the outlet opening 216, 216.1, 216.2 of the at least one drying chamber 210, 210.1, 210.2 by means of the pneumatic switching arrangement 230. In a second step 1200, method 1000 comprises activating the compressor 100 to draw in air from the environment U and compress the air to an operating pressure pB. In a third step 1300, method 1000 comprises supplying the compressed compressed air DL at the compressed air connection 1, wherein the compressed air DL has an operating temperature TB. In a fifth step 1500, at least one drying chamber 210, 210.1, 210.2 is pressurized with the compressed air DL supplied at the compressed air connection 1 until a target pressure pZ of the compressed air DL is reached in the at least one drying chamber 210, 210.1, 210.2. The target pressure pZ is preferably higher than the operating pressure pB.Alternatively or additionally, the drying chamber 210, 210.1, 210.2 is pressurized until a target temperature TZ of the drying granules 212 is reached in the at least one drying chamber 210, 210.1, 210.2 and / or the compressed air DL in the drying chamber 210, 210.1, 210.2 is reached. The target temperature TZ is higher than the operating temperature TB. In a sixth step 1600, the process 1000 comprises venting the compressed air DL from the at least one drying chamber 210, 210.1, 210.2 into the environment U when the target pressure pZ and / or the target temperature TZ is reached.

[0112] Depending on the design of the compressed air supply system DS, either only one drying chamber 210, both drying chambers 210.1, 210.2 or selectively either the primary drying chamber 210.1 or the secondary drying chamber 210.2 is supplied with compressed air DL.

[0113] In a preferred embodiment of method 1000, it is provided that the venting of the compressed air DL from the at least one drying chamber 210, 210.1, 210.2 in step 1600 comprises, as sub-step 1610, the opening of the pressure limiting valve 251 when an opening pressure pO is exceeded in the at least one drying chamber 210, 210.1, 210.2.

[0114] The target pressure pZ preferably corresponds to at least the opening pressure pO, whereby the compressor remains activated for a predefined time period t in sub-step 1610 when the pressure relief valve 251 opens. The pressure relief valve 251 is designed such that when the compressed air DL is vented in step 1600 from at least one drying chamber 210, 210.1, 210.2 via the pressure relief valve 251, only a minimal pressure drop Ap occurs and preferably the pressure in the tracking chamber is kept essentially constant. The nominal diameter N of the pressure relief valve 251 is designed such that the volume flow V delivered through the pressure relief valve 251 corresponds to the volume flow V supplied by the compressor 100 at the compressed air connection 1. The nominal diameter N of the pressure relief valve 251 must be taken into account in addition to the volume flow rate V and the operating pressure pB as well as the pipe length.In this case, the continuous operation of compressor 100 at a constant pressure in the drying chamber 210, 210.1, 210.2, which essentially corresponds to the opening pressure pO, leads to a continuous heating of the compressed air DL conveyed. The temperature increase is preferably driven forward until a target temperature TZ is reached.

[0115] The pressure relief valve 251 can preferably be a self-opening pneumatic element or alternatively a pneumatic switching element which can be electrically or pneumatically controlled via a control device depending on provided sensor data.

[0116] Alternatively or additionally, the sixth step 1600, as sub-step 1620, comprises controlling the at least one vent valve EV1, EV2 to release the line volume LV upon reaching the target pressure pZ and / or the target temperature TZ. It is preferred that the vent valves EV1, EV2 are designed such that a pressure drop Ap of at least 30% occurs during venting, which causes condensate in the at least one drying chamber 210, 210.1, 210.2 to be expelled. Due to the increased pressure in the drying chamber and the associated temperature increase, the moisture bound in the drying granules evaporates and subsequently condenses. This condensate is then expelled by the sudden opening of the vent valve EV1, EV2.The target pressure pZ is preferably smaller than the opening pressure pO, so that the pressure relief valve 251 does not open when the target pressure pZ is reached.

[0117] Alternatively, sub-steps 1610 and 1620 can also be performed sequentially. In addition to opening the pressure relief valve 251 in sub-step 1610, the vent valve EV1, EV2 is then switched in sub-step 1620. In this case, the pressure in the drying chamber 210, 210.1, 210.2 is initially kept constant by the pressure relief valve 251 while the compressor 100 continues to operate, so that the compressed air DL heats up until the target temperature is reached or until a predefined time interval t has elapsed. Subsequently, the vent valve EV1, EV2 is activated in sub-step 1620 to release the line volume LV.

[0118] The provision of compressed compressed air DL at the compressed air connection 1 in the third process step 1300 preferably comprises as sub-step 1310 the return of compressed air DL from the pneumatic main line 21 to the high-pressure stage 110.2 of the compressor 100 (see FIG. 4a and FIG. 4b) until a supply temperature TV is reached in the drying granules 212 of the at least one drying chamber 210 and / or until a predefined supply time tV has elapsed.

[0119] After the drying chamber has been vented by the pressure relief valve 251 or one of the venting valves EV1, EV2, in a seventh step 1700 preferably the compressor 100 is deactivated when the target pressure pZ and / or the target temperature TZ is reached or after a predefined time period t has elapsed.

[0120] Preferably, the process 1000 comprises, in an eighth step 1800, filling the reservoir 500 with dried compressed air DL at a second target pressure pZ2, which is higher than the operating pressure pB, and in a subsequent ninth step 1900, passing the compressed air DL at the second target pressure pZ, in particular in countercurrent flow G (see FIG. 2), through the at least one drying chamber. The eighth and ninth process steps 1800 and 1900 can be carried out independently of the other process steps whenever a need for regeneration is detected and the reservoir is filled.

[0121] Preferably, the method 1000 further comprises one or more monitoring steps 1410, 1420, 1430, 1440. In a first sub-step 1410, the method 1000 comprises monitoring the temperature ST of the drying granules 212 or of the compressed air DL located in the drying chamber 210, 210.1, 210.2. Preferably, the temperature ST is monitored by at least one sensor 240, in particular a temperature sensor. The monitored temperature ST is compared with the target temperature TZ, and when the target temperature TZ is reached, the next process step is initiated. In a second sub-step 1420, the method comprises monitoring the supply temperature TV of the supplied compressed air DL. The supply temperature is also preferably monitored by a sensor 240, in particular a temperature sensor.

[0122] In a third step 1430, the process 1000 comprises monitoring the pressure SP of the compressed air DL in the at least one drying chamber. The pressure SP can preferably be monitored via a sensor 240, in particular a pressure sensor U / P, or derived from the runtime L of the compressor 100 and the volume flow V and / or the compressor speed v. The monitored pressure SP is compared with the target pressure pZ, and when the target pressure pZ is reached, the next process step is initiated.

[0123] In a fourth step 1440, the method 1000 preferably comprises monitoring the saturation SA (see FIG. 8) of the drying granules 212 to identify a regeneration requirement RB of the at least one drying chamber 210, 210.1, 210.2. The monitoring of the saturation SA is carried out in particular by modeling the amount of water stored in the drying chamber 210, 210.1, 210.2 using the runtime L of the compressor 100 and the compressor speed v.

[0124] In a fifth sub-step 1450, the method 1000 preferably comprises monitoring a moisture content SH of the ambient air LU (see FIG. 2).

[0125] Process steps 1100, 1200, 1300, 1500, and 1600 are preferably carried out if the saturation SA exceeds a maximum saturation limit SAG1 and the humidity SH of the ambient air LU is below a first humidity limit GH1. Alternatively or additionally, the steps are carried out if the saturation SA exceeds a minimum saturation limit SAG2 and the humidity SH is below a second humidity limit GH2, which is lower than the first humidity limit GH1.

[0126] In summary, the invention relates to a method for operating a compressed air supply system, comprising the steps of: a) limiting at least one conduit volume connected to an outlet opening of the at least one drying chamber by means of a pneumatic switching arrangement of a compressed air supply system,

[0127] b) Activating a compressor to draw in and compress ambient air to an operating pressure,

[0128] c) Providing the compressed air at a compressed air connection, wherein the compressed air has an operating temperature,

[0129] d) Pressurizing at least one drying chamber with the compressed air supplied at the compressed air connection until a target pressure of the compressed air in the at least one drying chamber is reached, which is higher than the operating pressure, and / or until a target temperature of a drying granulate located in the drying chamber is reached, which is higher than the operating temperature,

[0130] e) Venting the compressed air from the at least one drying chamber into the environment upon reaching the target pressure and / or target temperature. The invention further relates to a compressed air supply system for carrying out the process.

[0131] Other variations of the disclosed embodiments can be understood and carried out by a person skilled in the art when carrying out the claimed invention with reference to the drawings, the disclosure and the accompanying claims.

[0132] In the claims, the word "comprehensive" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0133] A single unit or device can perform the functions of several elements listed in the claims. The fact that certain measures are listed in different interdependent claims does not mean that a combination of these measures cannot be advantageous.

[0134] Any reference numerals in the claims are not to be understood as limiting the scope of application. Reference numeral list (part of the description)

[0135] 0 Intake port

[0136] 0.1 Air filter

[0137] 1 compressed air connection

[0138] 1.1 Compressor connection

[0139] 2 compressed air supply connections

[0140] 2.1 Supply connection

[0141] 3 vent connection

[0142] 3.1, 3.2 Vent pipe connections

[0143] 10 Intake pipe

[0144] 13 Vent line

[0145] 13.1 Primary venting path

[0146] 13.2 secondary venting path

[0147] 14 Control pressure line

[0148] 15 Valve vent line

[0149] 21 pneumatic main line

[0150] 21 A First pneumatic main line section 21 B Second pneumatic main line section 21 C Third pneumatic main line section 21 D Fourth pneumatic main line section 22 Bypass line

[0151] 22A first bypass section

[0152] 22B Bypass connection cable

[0153] 22C second bypass section

[0154] 24 Return line

[0155] 30 Throttle valve

[0156] 50 Air cooling

[0157] 100 compressors

[0158] 110 piston units

[0159] 110.1 Low-pressure stage

[0160] 110.1 A first step entrance

[0161] 110.2 High pressure stage

[0162] 110.2A second stage intake

[0163] 120 Electric motor 00 Compressed air supply system

[0164] 10. Multiple drying chambers 10.1 Primary drying chamber

[0165] 10.2 Secondary drying chamber 11.1 Primary inlet path

[0166] 11.2 secondary inlet path

[0167] 12 drying granule filling

[0168] 13 first front

[0169] 14 second front

[0170] 15.1 Primary inlet opening

[0171] 15.2 Secondary inlet opening

[0172] 16.1 Primary outlet opening

[0173] 16.2 secondary outlet opening

[0174] 17 Plural of pipes

[0175] 17a first pipe

[0176] 17b second pipe

[0177] 23 cases

[0178] 24 Feedback switching arrangement

[0179] 25 Return switching valve

[0180] 26 Return check valve

[0181] 30 pneumatic switching arrangement

[0182] 31 Secondary air dryer protection valve 32 (First) bypass switching valve

[0183] 33 secondary non-return valve 35 2 / 2-way valve

[0184] 36 2 / 3-way valve

[0185] 37 second bypass switching valve

[0186] 238 primary air dryer protection valve 240 sensors

[0187] 251 Pressure relief valve

[0188] 300 pneumatic systems

[0189] 301 Sensor cleaning device

[0190] 302 Level control device

[0191] 500 reservoir

[0192] PS pneumatic system ECU control unit

[0193] Vehicle

[0194] P Passenger cars

[0195] LT Air Dryer Unit

[0196] LE Air Dryer Unit

[0197] LU Air

[0198] EV vent valve assembly EV1, EV2 vent valves

[0199] SEV2 pilot valve

[0200] D throttle

[0201] D2 Bypass Throttle

[0202] Z1 Junction

[0203] Z2 junction

[0204] E Venting direction

[0205] G Countercurrent

[0206] B Filling direction

[0207] R radial direction

[0208] A axial direction

[0209] DL compressed air

[0210] GH1 first moisture content limit GH2 second moisture content limit RB regeneration requirement

[0211] S operating parameters

[0212] SA saturation

[0213] SAG1 maximum saturation limit SAG2 minimum saturation limit SH moisture content

[0214] SP Print

[0215] ST temperature

[0216] SV control signals

[0217] ST1 first switching position

[0218] ST2 second shift position

[0219] H moisture content

[0220] L runtime

[0221] TB operating temperature STP dew point

[0222] TV lead time

[0223] TV flow temperature

[0224] TZ target temperature

[0225] U surroundings

[0226] V Volume flow

[0227] N Nominal diameter

[0228] Ap pressure drop

[0229] pB Operating pressure

[0230] TB operating temperature

[0231] pZ (first) target pressure

[0232] pZ2 second target pressure

[0233] pO opening pressure

[0234] t time span

[0235] v compressor speed

[0236] Ap pressure drop

[0237] LVE inlet line volume 1000 process

[0238] DS compressed air supply system

Claims

Patent claims 1. Method (1000) for operating a compressed air supply system (DS), wherein the compressed air supply system (DS) comprises a compressor (100) for providing compressed air (DL) at a compressed air connection (1) and a compressed air supply system (200) connected to the compressed air connection (1) for supplying a pneumatic system (300) connected to a compressed air supply connection (2), wherein the compressed air supply system (200) comprises an air dryer unit (LE) with at least one drying chamber (210, 210.1, 210.2) containing drying granules (212) for drying compressed air (DL) guided through the drying chamber (210, 210.1, 210.2) in a filling direction (B), where the procedure (1000) comprises the following steps: a) Limit (1100) at least one conduit volume (LV) connected to an outlet opening (216, 216.1, 216.2) of the at least one drying chamber (210, 210.1, 210.2) by a pneumatic switching arrangement (230) of the compressed air supply system (200), b) Activating the compressor (100) to draw in and compress (1200) ambient air (LU) to an operating pressure (pB), c) Providing (1300) the compressed compressed air (DL) at the compressed air connection (1), wherein the compressed air (DL) has an operating temperature (TB), d) Pressurizing (1500) the at least one drying chamber (210, 210.1, 210.2) with the compressed air (DL) supplied at the compressed air connection (1) until a target pressure (pZ) of the compressed air (DL) is reached in the at least one drying chamber (210, 210.1, 210.2) which is higher than the operating pressure (pB), and / or until a target temperature (TZ) of the drying granules (212) is reached in the at least one drying chamber (210, 210.1, 210.2) which is higher than the operating temperature (TB), e) Venting (1600) the compressed air (DL) from the at least one drying chamber (210, 210.1, 210.2) into the environment (U) when the target pressure (pZ) and / or the target temperature (TZ) is reached.

2. Method (1000) according to claim 1 , wherein the pneumatic switching arrangement (230) has at least one pressure limiting valve (251) which is located between the outlet opening (216, 216.1, 216.2) (216, 216.2, 216.2) which is arranged in at least one drying chamber (210, 210.1 , 210.2) and the compressed air supply connection (2), wherein the venting (1600) of the compressed air (DL) from the at least one drying chamber (210, 210.1, 210.2) comprises the following sub-step: - Opening (1610) of the pressure relief valve (251) when an opening pressure (pO) is exceeded in the at least one drying chamber (210, 210.1 , 210.2).

3. Method (1000) according to claim 1 or 2, wherein the pneumatic switching arrangement (230) has at least one venting valve (EV1, EV2) which is arranged between the outlet opening (216, 216.1, 216.2) of the at least one drying chamber (210, 210.1, 210.2) and a venting connection (3), and the venting (1600) of the compressed air (DL) from the at least one drying chamber (210, 210.1, 210.2) comprises the following sub-step: Controlling (1620) the vent valve (EV1 , EV2) to release the line volume (LV) when the target pressure (pZ) and / or the target temperature (TZ) is reached, wherein the at least one vent valve (EV1, EV2) is designed such that when the compressed air (DL) is vented from the at least one drying chamber (210, 210.1, 210.2) via the vent valve (EV1, EV2) a pressure drop (Ap) occurs, in particular a pressure drop (Ap) of at least 30%, preferably at least 80%.

4. Method (1000) according to claims 2 and 3, where the target pressure (pZ) is smaller than the opening pressure (pO), in particular at least 2% smaller than the opening pressure (pO).

5. Method (1000) at least according to claim 2, wherein the target pressure (pZ) is at least equal to the opening pressure (pO) and the compressor (100) remains activated for a predefined time period (t) when the pressure relief valve (251) is opened (1610), wherein the pressure relief valve (251) is designed such that when the compressed air (DL) is vented (1600) from the at least one drying chamber (210, 210.1, 210.2) via the pressure relief valve (251), a pressure drop (Ap) of a maximum of 5% occurs, in particular the pressure (S P ) in at least one drying chamber (210, 210.1, 210.2) is kept constant.

6. Method (1000) according to at least one of the preceding claims, wherein the compressor (100) is a multi-stage compressor (100) and comprises at least one low-pressure compressor stage (110.1) for drawing in and compressing compressed air (DL) from the environment (U) and one high-pressure stage (110.2) for providing compressed compressed air (DL) at the operating pressure (pB), furthermore, the sub-step encompasses: Return (1310) of the compressed air (DL) from the pneumatic main line (21 ) to the high-pressure stage (110.2) of the compressor (100) until a pre-flow temperature (TV) is reached in the drying granules (212) of the at least one drying chamber (210, 210.1, 210.2), and / or until a predefined pre-flow time (tV) has elapsed.

7. Method (1000) at least according to claim 6, wherein the intake (1200) of ambient air (LU) by the compressor (100) is carried out until an initial filling of an inlet line volume (LVE) in a filling direction (B) upstream of the at least one drying chamber (210, 210.1 , 210.2) is carried out and subsequently only the recirculated compressed air (DL) is compressed by the compressor (100) until the supply temperature (TV) is reached and / or until the predefined supply time (tV) has elapsed.

8. Method (1000) according to at least one of the preceding claims, further comprising at least one of the following steps: Activation (1620) of the vent valve (EV1 , EV2) after the predefined time interval (t) has elapsed, Deactivation (1700) of the compressor (100) upon reaching the target pressure (pZ) and / or the target temperature (TZ) and / or after a predefined time period (t), Monitoring (1410) the target temperature of the drying granules (212) in the at least one drying chamber (210, 210.1, 210.2), Monitoring (1420) the supply temperature (TV) of the supplied compressed air (DL), Monitoring (1430) of the target pressure (pZ) of the compressed air (DL) in the at least one drying chamber (210, 210.1 , 210.2).

9. Method (1000) according to at least one of the preceding claims, further comprising at least one of the following steps: Monitoring (1440) of a saturation (SA) of the drying granules (212) to identify a regeneration requirement (RB) of the at least one drying chamber (210, 210.1, 210.2), Monitoring (1450) of a humidity level (SH) of the ambient air (LU), wherein steps a) to e) are carried out in the event that the saturation (SA) exceeds a maximum saturation limit (SAG1) and the humidity (SH) of the ambient air (LU) is below a (first) humidity limit (GH1), and / or the saturation (SA) exceeds a minimum saturation limit (SAG2) and the moisture content (SH) is below a second moisture content limit (GH2) that is smaller than the first moisture content limit (GH1).

10. Method (1000) at least according to one of the preceding claims, wherein the target temperature (TT) is at least 60 °C, in particular at least 90 °C, and / or wherein the target pressure (pZ) is at least 18 bar, in particular at least 20 bar, and / or where the flow temperature (TV) is at least 60 °C, in particular at least 90 °C.

11. Method (1000) according to at least one of the preceding claims, wherein the drying chamber (210, 210.1, 210.2) is a primary drying chamber (210.1) and the air dryer unit (LE) comprises a secondary drying chamber (210.2), and wherein at least steps a) to e) are carried out selectively for partial regeneration of only the primary drying chamber (210.1) and / or only the secondary drying chamber (210.2) and for simultaneous regeneration of the primary drying chamber (210.1) and the secondary drying chamber (210.2).

12. Method (2000) at least according to one of the preceding claims, wherein the compressed air supply system (DS) further comprises a reservoir (500) connected to the compressed air supply connection (2) which is configured to store dried compressed air (DL) at the operating pressure (pB) for filling a pneumatic system (300), and wherein the procedure (1000) further comprises the steps: Filling (1800) the reservoir (500) with dried compressed air (DL) at a second target pressure (pZ2) that is higher than the operating pressure (pB), Guiding (1900) the compressed air (DL) with the second target pressure (pZ2) through at least one drying chamber (210, 210.1, 210.2).

13. Compressed air supply system (CS) for a vehicle (CS), in particular a passenger car (1100), comprising: a compressed air supply system (200) for providing compressed air (DL), with a compressed air connection (1) for connection to a compressor (100), a compressed air supply connection (2) for connecting a pneumatic system (300), a pneumatic main line (21) for conveying compressed air (DL) from the compressed air connection (1) to the compressed air supply connection (2) in a filling direction (B), an air dryer unit (LE) arranged in the pneumatic main line (21) for drying the compressed air (DL) guided in the filling direction (B), a throttle (D) arranged in the pneumatic main line in the filling direction (B) downstream of the air dryer unit (LE), and a vent line (13) branching off from the pneumatic main line (21) between the air dryer unit (LE) and the compressed air connection (1) to a vent connection (3), a compressor (100) for supplying compressed air (DL) for the compressed air supply system (200) at the compressed air connection (1), and a control unit (ECU) connected to the compressed air supply system (200) and the compressor (100) via a signal transmission characterized by a pneumatic switching arrangement (230) which is equipped to limit at least one conduit volume (LV) connected to an outlet opening (216, 216.1, 216.2) of the at least one drying chamber (210, 210.1, 210.2), wherein the control unit (ECU) is configured to execute a method according to any one of claims 1 to 12.

14. Compressed air supply system (CS) according to claim 13, wherein the pneumatic switching arrangement (230) has at least one pressure limiting valve (251) which is located between the outlet opening (216, 216.1, 216.2) of the at least a drying chamber (210, 210.1, 210.2) and the compressed air supply connection (2).

15. Compressed air supply system (CS) according to claim 14, wherein the pressure relief valve (251) is designed to release the compressed air (DL) from the air dryer unit (LE) without a pressure drop (Ap) > 5% when the compressor (100) is activated.

16. Compressed air supply system (DS) according to one of claims 13 to 15, wherein the pneumatic switching arrangement (230) has at least one vent valve (EV1, EV2) which is arranged between the outlet opening (216, 216.1, 216.2) of the at least one drying chamber (210, 210.1, 210.2) and the vent connection (3), and the at least one vent valve (EV1, EV2) is designed such that when the compressed air (DL) is vented from the at least one drying chamber (210, 210.1, 210.2) via the vent valve (EV1, EV2) a pressure drop (Ap) occurs, in particular a pressure drop (Ap) of at least 30%.

17. Compressed air supply system (DS) according to any one of claims 13 to 16, wherein the compressor (100) is a multi-stage compressor (100) and comprises at least one low-pressure compressor stage (110.1) for drawing in and compressing compressed air (DL) from the environment (U) and one high-pressure stage (110.2) for providing compressed compressed air (DL) at the operating pressure (pB), and the compressed air supply system (200) further comprises: a return line (24) which branches off from the pneumatic main line (21) between the compressed air connection (1) and at least one drying chamber (210, 210.1, 210.2) and connects to the second stage inlet (110.2A) of the high-pressure stage (110.2), and a pneumatic return switching arrangement (225) which is configured to connect the compressed air connection (1) to the at least one drying chamber (210, 210.1 , 210.2) in a first switching position (ST1) and to connect the compressed air connection (1) to the return line (24) in a second switching position (ST2).

18. Compressed air supply system (DS) according to any one of claims 13 to 17, wherein the drying chamber (210, 210.1, 210.2) is a primary drying chamber (210.1) and the air dryer unit (LE) has a secondary drying chamber (210.2), and wherein the control unit (ECU) is configured to selectively perform the method (1000) according to any one of claims 1 to 12 only for regenerating the primary drying chamber (210.1) or for regenerating the secondary drying chamber (210.2) or for simultaneously regenerating the primary drying chamber (210.1) and the secondary drying chamber (210.2).

19. Compressed air supply system (CS) according to any one of claims 13 to 18, further comprising: a bypass line (22) which branches off from the pneumatic main line (21) upstream of the air dryer unit (LE) in the filling direction (B) and reconnects to the pneumatic main line (21) downstream of the air dryer unit (LE) and is connected to the vent line (13).

20. Vehicle (FN), in particular passenger cars (P), with with a compressed air supply system (DS) according to one of claims 13 to 19, a pneumatic system (300) connected to the compressed air supply port (2) of the compressed air supply system (DS) for receiving dried compressed air (DL).

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