Compressed air supply system, pneumatic system, vehicle and operating procedures

Abstract

The invention relates to a compressed air supply system (100), comprising: - a compressor (101) with a first and second compressor stage (110, 120) for compressing compressed air (D) to two different pressure levels (D1, D2), - a compressed air supply system (201, 202, 203, 204, 205) with a main compressed air connection (1.1) connected to the compressor (101), a pneumatic main line (210) with an air dryer (220) for drying and conveying compressed air (D) from the main compressed air connection to a main compressed air supply connection (2.1), a supply line (251) for conveying compressed air (D) to a secondary compressed air supply connection (2.2) with a switchable pneumatic element (250) for enabling and disabling the supply line (251). The invention proposes that the main compressed air connection is connected to the second compressor stage (120) and that the compressed air supply system (201, 202, 203, 204, 205) has a secondary compressed air connection (1.2) connected to the first compressor stage (110), wherein the supply line (251) carries compressed air (D) from the secondary compressed air connection (1.2) to the secondary compressed air supply connection (2.2) and at least one secondary supply line (251.2) connected to the primary supply line (251.1) with a secondary pneumatic switching element (250.2) for connection to a compressed air source (Q) supplied by the main compressed air connection (1.1) for providing compressed air (D, D') at a third pressure level (D3) higher than the first pressure level, wherein the secondary pneumatic switching element (250.2) allows at least one unidirectional compressed air flow from the compressed air source (Q) into the primary supply line (251.1). The invention further relates to a pneumatic system, a vehicle, and an operating procedure.

Description

[0001] The invention relates to a compressed air supply system for a pneumatic system of a vehicle, in particular a commercial vehicle, which comprises a compressor, with a first compressor stage for compressing compressed air to a first pressure level and a second compressor stage for compressing the compressed air to a second pressure level, wherein the second pressure level is higher than the first pressure level.Furthermore, the compressed air supply system comprises a compressed air supply unit with a main compressed air connection for connection to the compressor, a main compressed air supply connection and a secondary compressed air supply connection for supplying compressed air, a pneumatic main line for conveying compressed air from the main compressed air connection to the main compressed air supply connection, an air dryer arranged in the pneumatic main line for drying the compressed air conveyed to the main compressed air supply connection, a supply line for conveying compressed air to the secondary compressed air supply connection, and a primary pneumatic switching element arranged in the supply line for selectively enabling and disabling the supply line. The main compressed air supply connection is configured for connecting a primary consumer, and the secondary compressed air supply connection is configured for connecting a secondary consumer.

[0002] The invention further relates to a pneumatic system with such a compressed air supply system, a vehicle with a corresponding pneumatic system, and a method for providing a compressed air supply for a vehicle, in particular a commercial vehicle.

[0003] In vehicles, compressed air supply systems serve to supply compressed air to compressed air consumers. For this purpose, compressed air is supplied to the compressed air supply system via the main compressed air connection by a compressor. In this description, compressor and compressor 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. The control of such a compressed air supply system is preferably carried out by an electronic control unit (ECU).

[0004] A compressed air supply system is used in all types of vehicles to supply compressed air to a consumer. The compressed air supply system, together with one or more consumers, forms a pneumatic system. Such consumers include, for example, air suspension systems, braking systems, sensor cleaning devices, horns, or tire inflation systems.

[0005] Air suspension systems can also include leveling devices that adjust the distance between the vehicle axle and the vehicle body. An air suspension system of the aforementioned pneumatic system comprises a number of air springs pneumatically connected to a common line (gallery). As the air pressure increases, these air springs raise the vehicle body, and as the air pressure decreases, they lower it. Lowering the vehicle body requires venting the system, whereby compressed air from the system, and in particular from the air springs, is released to the environment via a vent path in the compressed air supply system.Similarly, in a braking system, a braking force is applied by supplying compressed air via the compressed air supply system, and to release the brakes of such a braking system, venting of the consumer is necessary, whereby compressed air from the consumer is released to the environment via a vent line of the compressed air supply system.

[0006] Furthermore, there are consumers, such as sensor cleaning devices, that form an open compressed air supply with the corresponding compressed air supply systems. Compressed air is supplied to the consumer from the compressed air supply system, and the used compressed air is then released from the consumer into the environment. A sensor cleaning device can be used to clean surfaces on a vehicle, particularly sensor surfaces, using at least one cleaning fluid, such as compressed air. Regular cleaning of sensor surfaces on the vehicle can reduce sensor contamination and thus improve sensor reliability.Consumers, such as sensor cleaning equipment in particular, may also require compressed air at an increased pressure level on demand, for example to efficiently remove heavy soiling from sensors or to provide a high volume of air as needed - regulated down to the required system pressure.

[0007] To ensure the long-term operation of the compressed air supply system, a pneumatic main line of the system includes an air dryer to dry the compressed air. This provides the consumer with dry compressed air at the point of use and prevents moisture accumulation in the consumer's system. Moisture can lead to valve-damaging crystal formation and other undesirable defects, especially at relatively low temperatures. An air dryer contains a desiccant, typically desiccant granules, through which the compressed air flows, allowing the granules to adsorb any moisture present in the compressed air. An air dryer can also be designed as a regenerative air dryer.This can be achieved by passing compressed air from a reservoir or air springs through the drying granules – usually in counterflow, but sometimes also in parallel flow relative to the filling direction. The filling direction describes the conveying direction from the respective compressed air connection to the respective compressed air supply connection.

[0008] If the consumer and the compressed air supply system form a closed compressed air supply, the compressed air returned from the consumer is usually used for regeneration.

[0009] In compressed air supply systems for brake systems or sensor cleaning devices, the challenge lies in the fact that the compressed air supplied at the compressed air connection cannot be returned to the compressed air supply system, but is instead expelled to clean the sensors. Thus, unlike known compressed air supply systems, such as those shown in DE102017010772 A1, no compressed air already dried by the air dryer remains in the compressed air supply system or at the compressed air consumer. For this reason, consumers with open compressed air supplies, such as sensor cleaning devices or signal horns, are often supplied by compressed air supply systems without an air dryer.However, drying the compressed air supplied by the compressed air supply system for the sensor cleaning device or other consumers may be necessary due to weather conditions in order to prevent corrosion and frost-related damage and functional impairments to the lines of the compressed air supply system and the consumers at temperatures below freezing.

[0010] In compressed air supply systems that serve both open and closed-loop consumers, a challenge arises: when supplying consumers with open-loop systems, the saturation of the air dryer is accelerated significantly without any compressed air being returned for its regeneration. Consequently, the operating time of compressed air supply systems serving two or more consumers with both open and closed-loop systems is considerably reduced.

[0011] For example, WO0176898A1 shows a single-stage compressor with an attached air suspension system and a connected tire inflation system. When the tire inflation system is supplied with moist compressed air from the compressor, moist compressed air is also pumped to the air dryer, thus accelerating the saturation of the air dryer.

[0012] Furthermore, in sensor cleaning devices, for example, it may be desirable to temporarily provide compressed air at an increased pressure level due to heavy sensor contamination. However, a continuous supply of compressed air at this increased pressure level leads to undesirable oversizing or increased strain on the compressor.

[0013] This is where the invention comes in, the object of which is to provide a compressed air supply system that overcomes at least one of the disadvantages known from the prior art. In particular, the object of the present invention is to increase the operating time of compressed air supply systems for supplying two or more consumers that do not exclusively return compressed air to the compressed air supply system, while simultaneously ensuring reliable operation even with varying operating requirements of the consumers.

[0014] The problem is solved in a first aspect of the invention by a compressed air supply system according to claim 1. In particular, the invention proposes that the compressed air supply system further comprises an auxiliary compressed air connection which is connected to the first compressor stage, wherein the supply line is configured to carry compressed air from the auxiliary compressed air connection to the auxiliary compressed air supply connection, and the auxiliary compressed air supply connection is configured to provide compressed air at the first pressure level, and that the main compressed air connection is connected to the second compressor stage and the main compressed air supply connection is configured to provide compressed air at the second pressure level.The compressed air supply system has at least one secondary supply line branching off from the primary supply line with a secondary pneumatic switching element, wherein the secondary supply line is configured to connect to at least one compressed air source supplied via the main compressed air connection for providing compressed air at a third pressure level higher than the first pressure level, and wherein the secondary pneumatic switching element is configured to allow at least one unidirectional compressed air flow from the compressed air source into the primary supply line.

[0015] An air supply system according to the invention thus enables the supply of compressed air at the second pressure level to a main consumer via the main compressed air supply connection and, additionally, the supply of compressed air at a first, lower pressure level to an auxiliary consumer via the auxiliary compressed air supply connection. Thus, two independent compressed air supplies are enabled with only one compressor: one via the main compressed air connection and the main compressed air supply connection for supplying the main consumer, and the other via the auxiliary compressed air connection and the auxiliary compressed air supply connection for supplying the auxiliary consumer. Because the compressed air supplied to the auxiliary consumer has the first, lower pressure level, auxiliary consumers and main consumers with different pressure level requirements can be supplied according to their needs.Furthermore, supplying an auxiliary consumer with compressed air at the first, lower pressure level is advantageous if such an auxiliary consumer forms an open compressed air supply with the compressed air supply system. In this scenario, the compressed air supply system provides compressed air to the auxiliary consumer, who then releases the compressed air into the environment when operating the auxiliary actuators. The compressed air lost to the environment in this way cannot be returned to the compressed air supply system and therefore cannot be used for regenerating the air dryer. Because the compressed air supplied at the auxiliary compressed air connection is only at the first pressure level, the load on the compressor caused by the lost compressed air is reduced. This increases the efficiency of the compressed air supply system without impairing the function of the main consumer or the auxiliary consumer.

[0016] The term "switching valve" or "pneumatic switching element" refers to a pneumatic element that can switch between at least two switching states, either through controlled actuation—for example, electrical or pneumatic actuation—or automatically. Examples include 2 / 2-way valves, 3 / 2-way valves, and check valves. Check valves automatically switch from a closed position, in which bidirectional compressed air flow is impossible, to a release position, in which only unidirectional compressed air flow is possible, by applying an opening pressure. The opening pressure must be applied to the inlet side of the check valve, allowing compressed air to flow from the inlet side to the outlet side in the release position. Combinations of 2 / 2-way valves and check valves are also possible.

[0017] Furthermore, the secondary supply line allows compressed air at a third pressure level, higher than the first pressure level, to be fed into the primary supply line. This enables auxiliary consumers to be supplied with compressed air via the primary supply line and the secondary compressed air supply connection, with compressed air at either the first or the third pressure level. The compressed air supply system according to the invention thus allows for flexible responses to varying compressed air requirements from one or more auxiliary consumers.

[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, the pneumatic main line comprises a wet main line section extending between the main compressed air connection and the air dryer, and a dry main line section extending between the air dryer and the main compressed air supply connection. In particular, the wet main line section extends between the main compressed air connection and an air dryer inlet. In particular, the dry main line section extends between an outlet of the air dryer and the main compressed air supply connection. It should be understood that, when compressed air is guided through the pneumatic main line in a filling direction, the air dryer inlet and outlet each form the inlet and outlet of the air dryer.The filling direction refers to the direction in which compressed air is conveyed from the main compressed air connection to the main compressed air supply connection, so that a consumer at the main compressed air supply connection can be supplied with compressed air.

[0020] Preferably, the dry main line section of the pneumatic main line forms the at least one compressed air source, with the third pressure level corresponding to the second pressure level. The compressed air supplied by the compressed air source, i.e., the dry main line section, thus has a third pressure level corresponding to the second pressure level. Preferably, the at least one secondary supply line is a dry high-pressure supply line branching off from the dry main line section for carrying dry compressed air at the third pressure level. A secondary supply line can thus also supply an auxiliary consumer with dry compressed air, which has a third pressure level corresponding to the second pressure level, via the auxiliary compressed air supply connection. This allows for adjustments to varying weather conditions and system requirements regarding the required pressure level.For example, a sensor cleaning device can thus be supplied as needed as a secondary consumer at temperatures below freezing and with heavily soiled sensors.

[0021] The secondary pneumatic switching element is preferably a dry switching valve arranged in the dry high-pressure supply line, which is configured to allow at least a unidirectional flow of dried compressed air at the third pressure level from the dry main line section into the primary supply line. A suitable dry switching valve allows the supply of dry compressed air from the dry main line section into the primary supply line to be controlled and thus limited as needed.

[0022] Alternatively or additionally, the wet main line section of the pneumatic main line forms the at least one compressed air source, with the third pressure level corresponding to the second pressure level. The at least one secondary supply line is preferably a wet high-pressure supply line branching off from the wet main line section for carrying wet compressed air at the third pressure level. Thus, compressed air at the third pressure level, which is higher than the first pressure level, can be fed into the primary supply line via the wet high-pressure supply line and made available at the secondary compressed air supply connection as needed. This makes it possible to respond to varying compressed air requirements of a secondary consumer and to provide compressed air at a higher pressure level as required.Since the wet high-pressure supply line branches off from the main pneumatic line before the air dryer, the compressed air fed into the primary supply line via the wet high-pressure supply line does not accelerate the saturation of the air dryer. This allows, for example, a sensor cleaning device as a secondary consumer when sensors are heavily soiled, or a tire inflation system when tires are very low, to be supplied with compressed air at a higher pressure level as needed.

[0023] It is further preferred that the secondary pneumatic switching element is a wet switching valve arranged in the wet high-pressure supply line, which is configured to allow at least a unidirectional flow of moist compressed air at the third pressure level from the moist main line section into the primary supply line. This allows the controlled supply of moist compressed air at the third pressure level into the primary supply line. The flow of compressed air via the pneumatic main line to the main compressed air supply connection is only affected by the flow of moist compressed air at the third pressure level to the secondary compressed air supply connection if the wet switching valve allows the unidirectional flow of moist compressed air at the third pressure level.

[0024] It is further preferred that the compressed air supply system includes a bypass restrictor arranged in the wet high-pressure supply line, which is designed to reduce the pressure of the humid compressed air at the third pressure level. By reducing the pressure of the compressed air carried from the humid main line section via the wet high-pressure supply line, its relative humidity is reduced. This takes into account that the compressed air compressed by the second compressor stage and supplied at the main compressed air connection has a very high relative humidity due to the high pressure level (the second pressure level) and the high temperatures associated with compression. Reducing the relative humidity by means of the bypass restrictor thus reduces the risk of malfunctions of the auxiliary equipment due to the moisture content of the supplied compressed air.

[0025] Alternatively or additionally, a reservoir connectable to the main compressed air supply connection constitutes the at least one compressed air source, wherein the third pressure level corresponds to the second pressure level provided at the main compressed air supply connection. Alternatively, the third pressure level corresponds to a venting pressure level of the dry compressed air returned from the main consumer towards the main compressed air supply connection. The reservoir is preferably assigned to the main consumer and configured to store the compressed air provided at the main compressed air supply connection by the compressed air supply system or the compressed air returned from the main consumer, in particular its actuators, during venting towards the main compressed air supply connection. The venting pressure level can differ from the second pressure level of the compressed air provided at the main compressed air supply connection.

[0026] It is preferred that the at least one secondary supply line is a reservoir line connectable to the reservoir for supplying dry compressed air at the third pressure level. Supplying dry compressed air at the third pressure level from the reservoir allows for the supply of auxiliary consumers via the secondary compressed air supply connection in parallel with the supply of the main consumer via the main compressed air supply connection. The achievable volume flow rate is preferably higher than the compressed air supplied by the compressor in normal operation, i.e., without boosting. Because the compressed air in the reservoir is dry and has a third pressure level that is higher than the first pressure level, it is possible to respond to varying weather conditions and system requirements regarding the pressure level for the auxiliary consumers.

[0027] Preferably, the secondary pneumatic switching element is a reservoir switching valve arranged in the reservoir line, which is configured to allow at least a unidirectional flow of dry compressed air at the third pressure level from the reservoir into the primary supply line. Thus, the supply of dry compressed air from the reservoir to the primary supply line can be controlled as needed via the reservoir switching valve.

[0028] Alternatively or additionally, a gallery of the main consumer, connectable to the main compressed air supply connection, forms the at least one compressed air source, wherein the third pressure level corresponds to the venting pressure level of the dry compressed air returned from the main consumer towards the compressed air supply connection. Preferably, the at least secondary supply line is a gallery return line connectable to the gallery for carrying dry compressed air at the third pressure level. Thus, the compressed air returned towards the main compressed air supply connection for venting the main consumer, in particular its actuators, can be used to be fed into the primary supply line and made available at the secondary compressed air supply connection.In pneumatic systems, the compressed air returned to the gallery by the actuators of the main consumer during venting is often recirculated into the main pneumatic line for regeneration of the air dryer. This allows at least a portion of this compressed air to simultaneously supply the secondary consumer. Furthermore, a suitable gallery return line, connected to the primary return line, also enables the return of compressed air to the compressor. This allows, for example, the second compressor stage to be additionally charged with compressed air.

[0029] It is preferred that the secondary pneumatic switching element is a return control valve arranged in the gallery return line, which is configured to allow at least a unidirectional flow of dry compressed air at the third pressure level from the gallery into the primary supply line. Thus, the compressed air at the third pressure level from the gallery is only routed to the primary supply line via the gallery return line as needed. If this dry compressed air is not required to supply the auxiliary consumer at the auxiliary compressed air supply connection or to charge the second compressor stage, the return control valve closes the gallery return line to the flow of dry compressed air, so that it can only be routed back into the main pneumatic line of the pneumatic system for use in regenerating the air dryer.

[0030] The gallery and the reservoir are external compressed air sources that can be connected to the compressed air supply system. The dry main line section and the wet main line section, on the other hand, are internal compressed air sources that are part of the compressed air supply system according to the first aspect of the invention. Alternatively, the reservoir can also be an internal compressed air source of the compressed air supply system that can only be connected to the main compressed air supply connection or the gallery of the main consumer.

[0031] According to a further preferred embodiment, the first compressor stage has a first inlet and a first outlet connected to an intake port, and the second compressor stage has a second outlet connected to the main pneumatic line and a second inlet connected to the first outlet via a section of pipe. This is thus a two-stage compressor in which compressed air passes sequentially through the first and second compressor stages. In the first compressor stage, compressed air is preferably pre-compressed to a first pressure level and then passes through the pipe section into the second compressor stage, where the compressed air is preferably compressed to a second pressure level, i.e., a target pressure level. Such compressors are also referred to as twin compressors.

[0032] In embodiments where the compressed air source is provided on the one hand by the dry main line section and on the other hand by the gallery of the main consumer, and thus a dry high-pressure supply line and a gallery return line are present, it is preferred that the dry high-pressure supply line connects to the primary supply line at a first connection point and the gallery return line at a second connection point. It is further preferred that the compressed air supply system has a switchable shut-off valve arranged in the primary supply line between the first and second connection points, which is configured to selectively shut off and release the primary supply line.Thus, in the event of pressure differences between the compressed air supplied via the dry high-pressure supply line and the gallery return line, the flow of dry compressed air from the dry high-pressure supply line into the gallery return line is prevented. Furthermore, by blocking the primary supply line with the shut-off valve, particularly in twin compressors, compressed air for charging the second compressor stage can be directed to the auxiliary compressed air connection and then to an inlet of the second compressor stage.

[0033] Preferably, the compressed air supply system further comprises a compressor switching valve designed to selectively block and release the section of pipe. This allows the first compressor stage to be isolated from the second compressor stage as needed. It is therefore possible to supply compressed air to an auxiliary consumer at the first outlet of the first compressor stage, while no compressed air from the first compressor stage is present in the second compressor stage. Accordingly, no compressed air at the second compressed air level can be supplied via the second outlet of the second compressor stage and fed into the main pneumatic line via the main compressed air connection. The first compressor stage can thus be operated independently of the second compressor stage and used to supply compressed air.

[0034] Preferably, the compressor switching valve is a 2 / 2-way compressor valve, which is preferably normally closed and electrically actuated, or which is pneumatically actuated. In the case of a pneumatically actuated 2 / 2-way compressor valve, it is preferably actuated by a control pressure taken from the outlet side of the first compressor stage, i.e., the control pressure taken from the first outlet of the first compressor stage.

[0035] Electrically actuated valves have the advantage of short response times. Pneumatically actuated 2 / 2-way or 3 / 2-way valves, on the other hand, have the advantage that greater actuation forces are exerted by the control pressure. If, due to moisture present upstream of the air dryer in the filling direction, crystals form in the pneumatic main line and the supply line at sub-zero temperatures, higher actuation forces ensure trouble-free operation.

[0036] The invention solves the aforementioned problem in a second aspect by means of a pneumatic system according to claim 9. In particular, the invention proposes that the pneumatic system comprises a compressed air supply system according to the first aspect of the invention, a main consumer connected to the main compressed air supply port, and an auxiliary consumer connected to the auxiliary compressed air supply port. Such a pneumatic system, through the existing compressed air supply system, benefits from the advantages described above with regard to the first aspect of the invention. Advantages and preferred embodiments according to the first aspect of the invention are thus also advantages and preferred embodiments according to the second aspect of the invention, and vice versa.

[0037] Preferably, the main consumer includes a reservoir connected to the main compressed air supply connection and the reservoir line via at least one reservoir line section. The main consumer further includes a reservoir shut-off valve configured to allow at least a unidirectional flow of dry compressed air from the main compressed air supply connection into the reservoir and to at least selectively block the reservoir line section from the flow of dry compressed air from the reservoir line and / or the reservoir. Thus, the reservoir can preferably be used exclusively as a compressed air source to supply the secondary consumer, and backflow of the compressed air in the reservoir towards the main compressed air supply connection can be prevented, at least as needed.

[0038] Preferably, the main consumer is configured to form a closed compressed air supply with the compressed air supply system, such that compressed air is supplied to the main consumer to actuate a number of main actuators and compressed air is returned to the compressed air supply system to vent the main actuators.

[0039] Because the main consumer is a closed-loop compressed air supply system, the compressed air dried by the air dryer is not lost but can be reused to regenerate the air dryer. A suitably designed pneumatic system thus enables an increased operating time for the air dryer.

[0040] Preferably, the auxiliary consumer is configured to provide an open compressed air supply to the compressed air supply system, such that compressed air is supplied to the auxiliary consumer to actuate a number of auxiliary actuators and is then discharged by the auxiliary consumer into the surrounding environment. This allows the pneumatic system to operate efficiently, as the auxiliary consumer does not receive dried compressed air that would otherwise be released into the environment. Consequently, the air dryer is not burdened by the supply of compressed air that would otherwise be lost through discharge into the environment, thus preventing its saturation from accelerating.

[0041] In preferred embodiments, the main consumer is an air suspension system or a braking system and / or the secondary consumer is a sensor cleaning device or a tire inflation system or a horn or a braking system.

[0042] The invention solves the aforementioned problem in a third aspect by means of a vehicle according to claim 11. The invention proposes that such a vehicle has a pneumatic system according to the second aspect of the invention.

[0043] Through a suitable pneumatic 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 preferred embodiments and advantages according to the third aspect of the invention.

[0044] The invention solves the aforementioned problem in a fourth aspect by means of a method according to claim 12. In particular, the invention proposes a method for operating a pneumatic system, especially a pneumatic system according to the second aspect of the invention, which comprises the steps: - Compressing compressed air to a first pressure level with a first compressor stage and to a second pressure level with a second compressor stage (120), wherein the second pressure level is higher than the first pressure level, - Providing moist compressed air at the first pressure level at a secondary compressed air connection, - Providing moist compressed air at the second pressure level at a main compressed air connection, - Guiding the moist compressed air supplied at the main compressed air connection at the second pressure level through a pneumatic main line, wherein the moist compressed air at the second pressure level is dried by an air dryer arranged in the pneumatic main line, - Selective operation of the pneumatic system in a main consumer mode, a primary auxiliary consumer mode and at least one secondary auxiliary consumer mode, wherein in the main consumer mode the moist compressed air supplied at the main compressed air connection is guided at the second pressure level via the main pneumatic line towards a main compressed air supply connection, dried by an air dryer arranged in the main pneumatic line and supplied as dried compressed air at the second pressure level, and wherein in the secondary consumer mode compressed air is supplied at a secondary compressed air supply connection, wherein in the primary-auxiliary consumer mode, the moist compressed air supplied at the auxiliary compressed air connection is routed via the primary supply line to an auxiliary compressed air supply connection at the first pressure level and supplied as moist compressed air at the first pressure level, and wherein in the secondary auxiliary consumer mode compressed air with a third pressure level that is higher than the first pressure level is supplied from a compressed air source via at least one secondary supply line connected to the primary supply line and a secondary pneumatic switching element arranged in the primary supply line and is provided at the auxiliary compressed air supply connection.

[0045] By at least selectively separating the air dryer from the compressed air supply line and by providing compressed air at a first pressure level in a primary auxiliary consumer mode and at a third pressure level in a secondary auxiliary consumer mode, the method incorporates the advantages described above with respect to the first aspect of the invention. Advantages and preferred embodiments described with respect to the first and second aspects of the invention are also preferred embodiments of the method according to the fourth aspect of the invention.

[0046] It is preferred that the at least one secondary auxiliary user mode includes several or all of the following: - a first secondary auxiliary consumer mode in which the moist compressed air supplied at the main compressed air port is guided at the second pressure level via the pneumatic main line towards a main compressed air supply port, is dried by an air dryer arranged in the pneumatic main line, wherein the compressed air source is a dry main line section of the pneumatic main line extending between an air dryer outlet of the air dryer and the main compressed air supply port, and the third pressure level corresponds to the second pressure level, and wherein the secondary supply line is a dry high-pressure supply line branching off from the dry main line section for carrying dry compressed air at the third pressure level, - a second secondary auxiliary consumer mode in which the moist compressed air supplied at the main compressed air port is routed at the second pressure level via the pneumatic main line towards a main compressed air supply port, wherein the compressed air source is a moist main line section of the pneumatic main line extending between the main compressed air port and an air dryer inlet of the air dryer, and the third pressure level corresponds to the second pressure level, and wherein the secondary supply line is a wet high-pressure supply line branching off from the moist main line section for routing dry compressed air at the third pressure level, - a third secondary auxiliary consumer mode, wherein the compressed air source is a reservoir connectable to the main compressed air supply port, and the dry compressed air supplied at the main compressed air supply port at the second pressure level and / or dry compressed air returned from a main consumer towards the main compressed air supply port at a venting pressure level is stored in the reservoir, wherein the third pressure level corresponds to the second pressure level supplied at the main compressed air supply port or the venting pressure level, and wherein the secondary supply line is a reservoir line connectable to the reservoir for carrying dry compressed air at the third pressure level, - a fourth secondary auxiliary consumer mode, wherein the compressed air source is a gallery of the main consumer connectable to the main compressed air supply port, and dry compressed air at a venting pressure level is fed into the gallery for venting the main consumer, the third pressure level being the venting pressure level, and the secondary supply line is a gallery return line connectable to the gallery for feeding dry compressed air at the third pressure level.

[0047] By operating in the first secondary auxiliary consumer mode, an auxiliary consumer can also be supplied with dry compressed air via the auxiliary compressed air supply connection, which has a third pressure level corresponding to the second pressure level. This allows for a response to varying weather conditions and system requirements regarding the required pressure level. For example, a sensor cleaning device can thus be supplied as needed as an auxiliary consumer at temperatures below freezing and with heavily soiled sensors.

[0048] By operating in the second secondary auxiliary consumer mode, compressed air at the third pressure level, which is higher than the first pressure level, can be fed into the primary supply line via the wet high-pressure supply line and made available at the auxiliary compressed air supply connection as needed. This makes it possible to respond to varying compressed air demands from an auxiliary consumer and to provide compressed air at a higher pressure level as required. Since the wet high-pressure supply line branches off from the main pneumatic line before the air dryer, the compressed air fed into the primary supply line via the wet high-pressure supply line does not accelerate the saturation of the air dryer.For example, a sensor cleaning device can be used as a secondary consumer when sensors are heavily soiled, or a tire inflation system can be supplied with compressed air at a higher pressure level as needed when tire pressure is very low.

[0049] Operating in the third secondary / auxiliary consumer mode allows for the supply of auxiliary consumers via the secondary compressed air supply connection in parallel with the supply of the main consumer via the main compressed air supply connection. Because the compressed air in the reservoir is dry and has a third pressure level, which is higher than the first pressure level, the system can respond to varying weather conditions and system requirements regarding the pressure level for the auxiliary consumers.

[0050] By operating in the fourth secondary auxiliary consumer mode, the compressed air returned to the main compressed air supply connection for venting the main consumer, particularly its actuators, can be used to be routed into the primary supply line and made available at the auxiliary compressed air supply connection. In pneumatic systems, the compressed air returned to the gallery by the main consumer's actuators during venting is often used to regenerate the air dryer and then returned to the main pneumatic line. Thus, at least a portion of this compressed air can be used simultaneously to supply the auxiliary consumer. Furthermore, a corresponding gallery return line connected to the primary return line also allows the compressed air to be returned to the compressor. This enables, for example, the second compressor stage to be additionally charged with compressed air.

[0051] Preferably, operating the compressed air supply system in primary-auxiliary consumer mode comprises controlling a primary pneumatic switching element arranged in the primary supply line to selectively release the primary supply line. Thus, operation in primary-auxiliary consumer mode can be enabled on demand by controlling the primary pneumatic switching element and releasing the primary supply line.

[0052] Preferably, operating the compressed air supply system in secondary auxiliary consumer mode includes controlling the secondary pneumatic switching element arranged in the secondary supply line to selectively release the secondary supply line. Thus, operating the pneumatic system in secondary auxiliary consumer mode is enabled on demand by controlling the pneumatic element, which then selectively releases the secondary supply line.

[0053] Controlling the primary pneumatic switching element or the secondary pneumatic switching element allows for quick and flexible variation of the required primary or secondary consumer modes.

[0054] It is further preferred that the control of the secondary pneumatic switching element arranged in the secondary supply line for the selective release of the secondary supply line comprises one, several or all of the following: - Actuating the secondary pneumatic switching element, which is designed as a dry switching valve arranged in the dry high-pressure supply line, to allow a unidirectional flow of dried compressed air at the third pressure level from the dry main line section into the primary supply line, - Actuation of the secondary pneumatic switching element, which is designed as a wet switching valve arranged in the wet high-pressure supply line, to allow a unidirectional flow of moist compressed air at the third pressure level from the moist main line section into the primary supply line, - Actuating the secondary pneumatic switching element, which is designed as a reservoir switching valve arranged in the reservoir line, to allow a unidirectional flow of dry compressed air at the third pressure level from the reservoir into the primary supply line, and - Controlling the secondary pneumatic switching element, which is a return switching valve arranged in the gallery return line, to allow a unidirectional flow of dry compressed air at the third pressure level from the gallery into the primary supply line.

[0055] By controlling the appropriately designed pneumatic switching elements, the method takes advantage of the benefits described in relation to the preferred embodiments of the first aspect of the invention.

[0056] The method preferably further comprises, in the case where, in a pneumatic system to be operated, the first compressor stage has a first inlet and a first outlet connected to an intake port, and the second compressor stage has a second outlet connected to the main pneumatic line and a second inlet connected to the first outlet via a section of pipe, the actuation of a compressor switching valve to selectively block the section of pipe during operation of the pneumatic system in primary-auxiliary consumer mode. Thus, if only compressed air at the first pressure level is required for the auxiliary consumer at the secondary compressed air supply connection, the second compressor stage is blocked by actuating the compressor switching valve. Consequently, no compressed air at the second pressure level reaches the main compressed air connection via the second compressor stage and thus does not reach the air dryer via the main pneumatic line.The saturation of the air dryer is therefore not progressing.

[0057] The invention solves the aforementioned problem in a fifth aspect by means of a control unit according to claim 17. In particular, the invention proposes a control unit for controlling a pneumatic system of a vehicle, especially a passenger car, which solves the aforementioned problem in that the control unit is configured for selectively operating the pneumatic system in a main consumer mode, a primary auxiliary consumer mode and at least one secondary auxiliary consumer mode in a method according to the fourth aspect of the invention.

[0058] Because the control unit is configured to operate the pneumatic system in the various consumer modes, it benefits from the advantages described in relation to the method according to the fourth aspect of the invention. Advantages and preferred embodiments according to the fourth aspect of the invention are also preferred embodiments and advantages according to the fifth aspect of the invention, and vice versa.

[0059] Embodiments of the invention are now described below with reference to the drawings and comparison with 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 details regarding 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. Where specified dimensioning ranges are given, values ​​lying within the stated limits are also disclosed as limit values ​​and may be used and claimed as desired.

[0060] 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: Fig. 1a: a vehicle with a pneumatic system schematically in a first embodiment in a primary-auxiliary consumer mode; Fig. 1b: a vehicle with a pneumatic system schematically in a first embodiment in a first secondary auxiliary consumer mode; Fig. 1c: a vehicle with a pneumatic system schematically in a first embodiment in a main consumer mode; Fig. 2a: a vehicle with a pneumatic system schematically in a second embodiment in a primary-auxiliary consumer mode; Fig. 2b: a vehicle with a pneumatic system schematically in a second embodiment in a first secondary auxiliary consumer mode; Fig. 2c: a vehicle with a pneumatic system schematically in a second embodiment in a second secondary auxiliary consumer mode; Fig. 2d: a vehicle with a pneumatic system schematically in a second embodiment in a main consumer mode; Fig. 3a: a vehicle with a pneumatic system schematically in a third embodiment in a primary-auxiliary consumer mode; Fig. 3b: a vehicle with a pneumatic system schematically in a third embodiment in a first secondary auxiliary consumer mode; Fig. 3c: a vehicle with a pneumatic system schematically in a third embodiment in a third secondary auxiliary consumer mode; Fig. 3d: a vehicle with a pneumatic system schematically in a third embodiment in a main consumer mode; Fig. 4a: a vehicle with a pneumatic system schematically in a fourth embodiment in a primary-auxiliary consumer mode; Fig. 4b: a vehicle with a pneumatic system schematically in a fourth embodiment in a first secondary auxiliary consumer mode; Fig. 4c: a vehicle with a pneumatic system schematically in a fourth embodiment in a third secondary auxiliary consumer mode; Fig. 4d: a vehicle with a pneumatic system schematically in a fourth embodiment in a fourth secondary auxiliary consumer mode; Fig. 4e: a vehicle with a pneumatic system schematically in a fourth embodiment in a main consumer mode; Fig. 4f: a vehicle with a pneumatic system schematically in a fourth embodiment in a reflow operating mode; Fig. 5: a vehicle with a pneumatic system schematically in a fifth embodiment in a primary-auxiliary consumer mode; Fig. 6: a vehicle with a pneumatic system schematically in a sixth embodiment in a primary-auxiliary consumer mode; Fig. 7: a vehicle with a pneumatic system schematically in a seventh embodiment in a primary-auxiliary consumer mode; Fig. 8: a method for operating a pneumatic system according to the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. 7.

[0061] Fig. Figures 1a to 1c show a vehicle 1000, which may preferably be a passenger car 1100.

[0062] The vehicle 1000 comprises a pneumatic system 10 with a compressed air supply system 201 for providing compressed air D, D' and a main consumer 300 as well as at least one secondary consumer 400 for taking off the compressed air D, D'.

[0063] The compressed air supply system 201 includes a compressor 101 for compressing moist compressed air D and a compressed air supply system 201 for directing the compressed compressed air D, D' to the main consumer 300 and the auxiliary consumer 400.

[0064] The compressed air supply system 201 comprises a main compressed air connection 1.1 for connection to the compressor 101 and a main compressed air supply connection 2.1, which is configured for connecting the main consumer 300. Dried compressed air D' is supplied to the main consumer 300 at the main compressed air supply connection 2.1.

[0065] The compressed air supply system 201 also includes an auxiliary compressed air supply connection 2.2, which is configured for connecting the auxiliary consumer 400. The compressed air supply system 201 is configured to provide compressed, moist compressed air D at the auxiliary compressed air supply connection 2.2 for the auxiliary consumer 400.

[0066] Furthermore, the compressed air supply system 201 includes a combined intake and exhaust connection 0 / 3. It should be understood that the compressed air supply system 201 can alternatively also include two separate connections: one for venting the compressed air supply system (namely an exhaust connection) and one for drawing compressed air for the compressor (namely an intake connection). Such connections for compressed air supply systems are known.

[0067] The intake and exhaust port 0 / 3 is connected to the compressor 101 via an intake line 213 of the compressed air supply system 201. A first compressor stage 110 with a first inlet 111 for connection to the intake line 213 is provided. The first compressor stage 110 compresses the aspirated moist compressed air D preferably to a first pressure level D1 and makes this compressed air available at a first outlet 112. In the Fig. The compressor 101 shown in Figure 1 is a so-called twin compressor. This is a preferred embodiment, which is not to be understood as limiting. In the case of a twin compressor, the compressed air D, compressed to the first pressure level D1, is supplied from the first outlet 112 of the first compressor stage 110 to a second compressor stage 120. The second compressor stage 120 has a second inlet 121 and a second outlet 122. The first outlet 112 is connected to the second inlet 121 of the second compressor stage 120 via a pipe section 140. The second compressor stage 120 is configured to compress the moist compressed air D, compressed to the first pressure level D1, to a second pressure level D2 and make it available at the second outlet 122. The first compressor stage 110 and the second compressor stage 120 are preferably driven by a motor 130.The moist compressed air D, compressed to the second pressure level D2, is supplied to the compressed air supply system 201 at the main compressed air connection 1.1.

[0068] The compressed air supply system 201 comprises a pneumatic main line 210 for conveying the compressed air D supplied at the main compressed air connection 1.1 to the main compressed air supply connection 2.1. The compressed air supply system 201 also includes an air dryer 220 arranged in the pneumatic main line 210, which is configured to dry the moist compressed air D supplied from the main compressed air connection 1.1 to the air dryer 220, so that dry compressed air D' is supplied at the main compressed air supply connection 2.1. Through compression by means of the second compressor stage 120, the dry compressed air D' supplied at the main compressed air supply connection 2.1 has the second compressed air level D2. The compressed air D, D' is conveyed in a filling direction B from the main compressed air connection 1.1 to the main compressed air supply connection 2.1. The pneumatic main line 210 is subdivided into a wet main line section 210.1, which is designed downstream of the air dryer in the filling direction B, and a dry main line section 210.2, which is designed upstream of the air dryer 220 in the filling direction B.

[0069] In the filling direction B downstream of the air dryer 220, a throttle 230 is also arranged, which is designed to reduce the relative humidity of the compressed air by expanding it.

[0070] The compressed air supply system 201 further comprises a primary supply line 251.1, which is designed to carry compressed air D from the secondary compressed air connection 1.2 to the secondary compressed air supply connection 2.2. A primary pneumatic switching element 250.1 is arranged in the primary supply line 251.1. The primary pneumatic switching element 250.1 is designed to selectively block and release the primary supply line 251.1.

[0071] The auxiliary compressed air connection 1.2 is connected to the first compressor stage 110 and, in particular, to a first outlet 112 of the first compressor stage 110. Compressed air D with the first pressure level D1 is thus conveyed from the first compressor stage 110 to the compressed air supply connection 2.2 via the auxiliary compressed air connection 1.2 and the primary supply line 251.1. The auxiliary consumer 400 is thus supplied with moist compressed air D, which has a first pressure level D1 that is lower than the second pressure level D2 provided by the second compressor stage 120 at the main compressed air connection 1.1.

[0072] The primary supply line 251.1 can also be a boost line, to which a reservoir (not shown) for charging the second compressor stage 120 can also be connected. To charge the second compressor stage 120 via such a boost line, compressed air D is supplied to the second inlet 121 of the second compressor stage 120 via the boost line and the pipe section 140.

[0073] The compressed air supply system 201 further comprises at least one secondary supply line 251.2 connected to the primary supply line 251.1. The at least one secondary supply line 251.2 is configured for connection to a compressed air source Q. In this case, the compressed air source Q is the dry main line section 210.2, which is connected to the secondary supply line 251.2. A secondary pneumatic switching element 250.2 is arranged in the secondary supply line 251.2. The secondary pneumatic switching element 250.2 is configured to allow at least a unidirectional flow from the compressed air source Q, in this case the dry main line section 210.2, into the primary supply line 251.1. The secondary supply line 251.2 is thus configured to supply dry compressed air D' with a third pressure level D3, which is higher than the first pressure level D1, into the primary supply line 251.1. Since the compressed air source Q is provided by the dry main line section 210.2, the third pressure level D3 corresponds to the second pressure level D2. The supply of dry compressed air D' with the third pressure level D3 to the secondary compressed air supply connection 2.2 via the secondary supply line 251.2 and the primary supply line 251.1 is therefore possible if the secondary pneumatic switching element 250.2 allows at least the unidirectional flow of dry compressed air D' towards the secondary compressed air supply connection 2.2.

[0074] The compressed air supply system 201 further comprises a venting valve arrangement 260, which is designed to allow venting of the main consumer 300 and the compressed air supply system 201, in particular the pneumatic main line 210, via the combined intake and venting connection 0 / 3.

[0075] The main consumer 300, together with the compressed air supply system 201, forms a closed compressed air supply G. To vent the main consumer 300, compressed air is returned to the main pneumatic line 210 and conveyed to the air dryer 220 against the filling direction B. The compressed air returned against the filling direction B is first depressurized by the throttle 230, thus reducing its relative humidity. As this depressurized compressed air is returned through the air dryer 220, moisture from a drying granulate in the air dryer 220 is bound, thereby regenerating the air dryer 220. Upstream of the air dryer 220 in the filling direction B, a vent line 216 branches off from the main pneumatic line 210, specifically from the moist section of the main line 210.The pneumatic main line 210 branches off and is configured to direct the compressed air returned by the air dryer 220 against the filling direction B via the venting valve assembly 260 towards the combined intake and venting port 0 / 3. The venting line 216 connects to the intake line 213. The venting valve assembly 260 includes a relay valve 261, which is configured to selectively block and release the venting line 216. The relay valve 261 is actuated via a venting pilot valve 262. Such venting valve assemblies 260 are known and are not described in detail here. The function of the relay valve is, in particular, to prevent dry air from flowing back into the air dryer 220, for example, when measuring the pressure of the air springs 321, 322, 323, 324. This prevents the air dryer 220 from filling up (“parasitic” volume) and reduces the amount of air lost.This prevents the vehicle from unintentionally "sagging" and needing to be leveled again.

[0076] The main consumer 300 is preferably an air spring system 301. The air spring system 301 comprises a gallery 313 connected to the main compressed air supply connection 2.1, to which a number of main actuators 320 are connected. The main actuators 320 are preferably air spring bellows 321, 322, 323, 324, which are connected to the gallery 313 via a main consumer valve arrangement 330. The main consumer valve arrangement 330 comprises a number of main consumer switching valves 331, 332, 333, 334, wherein each main consumer switching valve 331, 332, 333, 334 is assigned to a corresponding air spring bellows 321, 322, 323, 324. The main consumer switching valves 331, 332, 333, 334 shown are designed as 2 / 2-way valves and configured to operate in the Fig. 1a and Fig. The first switching position S1 shown in 1b blocks the flow of compressed air between gallery 313 and the main actuators 320. In a Fig. In the second switching position S2 shown in 1c, the main consumer switching valves 331, 332, 333, 334 are configured to allow a bidirectional compressed air flow between the gallery 313 and the main actuators 320.

[0077] Furthermore, the main consumer 300 includes a pressure sensor 360 connected to the gallery 313, which is configured to detect a gallery pressure DG. This gallery pressure DG can preferably be used as a control signal for controlling the gallery valve 350 or the main consumer valve arrangement 330.

[0078] The auxiliary consumer 400 preferably forms an open compressed air supply O with the compressed air supply system 201. Compressed air D is conveyed from the main compressed air connection 1.1 via the primary supply line 251.1 to the auxiliary consumer 400, which, however, releases the compressed air D into the environment A via auxiliary consumer switching valves 420, 430 when the auxiliary actuators (not shown) are operating. The auxiliary consumer switching valves 420, 430 are connected to the auxiliary compressed air supply connection 2.2 via a common supply line 410.

[0079] The auxiliary actuators are preferably cleaning nozzles of a sensor cleaning device 401. The auxiliary consumer switching valves 420, 430 are in this case in Fig. 1c is shown in a locked position SP, in which the supply line 410 is blocked. The auxiliary consumer switching valves 420, 430 are further shown in Fig. 1a and Fig. 1b is shown in a release position FP, releasing the supply line 410 and the compressed air D provided at the auxiliary compressed air supply connection 2.2 is supplied to the cleaning nozzles (not shown) of the sensor cleaning device 401 and discharged via these to the environment A. It should be understood that both the air spring system 301 and the sensor cleaning device 401 are merely examples of main consumer 300 and auxiliary consumer 400, which are not to be interpreted restrictively.

[0080] The vehicle 1000 also includes a control unit 20, which is designed to control the pneumatic system 10 for operation in different operating modes.

[0081] The Fig. Figures 1a to 1c show the pneumatic system 10 and in particular the compressed air supply system 100 in operation in different operating modes SM1, SM2, M1.

[0082] Fig. Figure 1a shows operation in a primary-auxiliary consumer mode SM1. In primary-auxiliary consumer mode SM1, the moist compressed air D supplied at the auxiliary compressed air port 1.2, with the first pressure level D1, is routed via the primary supply line 251.1 to the auxiliary compressed air supply port 2.2 and supplied as moist compressed air D with the first pressure level D1. The primary pneumatic switching element 250.1 is controlled by the control unit 20 such that the primary supply line 251.1 is selectively enabled. The primary pneumatic switching element 250.1 is preferably a 2 / 2-way valve, which, in the second switching position S2 shown, allows bidirectional flow of moist compressed air D through the primary supply line 251.1.Furthermore, in primary auxiliary consumer mode SM1, the control unit 10 preferentially controls the compressor switching valve 290 so that it separates the second compressor stage 120 from the outlet 112 of the first compressor stage 110.

[0083] Fig. Figure 1b shows the pneumatic system 10 and, in particular, the compressed air supply system 100 in a secondary auxiliary consumer mode SM2. In the first variant AM1 of auxiliary consumer mode SM2 shown, dried compressed air D' with a third pressure level D3, which is higher than the first pressure level D1, is supplied from the compressed air source Q via the at least one secondary supply line 251.2 connected to the primary supply line 251.1 and the secondary pneumatic switching element 250.2 and is made available at the auxiliary compressed air supply connection 2.2.

[0084] In the illustrated embodiment of the compressed air supply system 100, in the first variant AM1 of the secondary auxiliary consumer mode SM2, the moist compressed air D supplied at the main compressed air connection 1.1 is thus guided at the second pressure level D2 via the pneumatic main line 210 towards the main compressed air supply connection 2.1 and dried by the air dryer 220. The compressed air source Q is provided by the dry main line section 210.2, and the secondary supply line 251.2, designed as a dry high-pressure supply line 271, carries the dry compressed air D' from the dry main line section 210.2 via the secondary pneumatic switching element 250.2, designed as a dry switching valve 270, into the primary supply line 251.1. The dry compressed air then flows via the dry high-pressure supply line 271 to the auxiliary compressed air supply connection 2.1.2 guided dry compressed air D' has the third pressure level D3, which in this case corresponds to the second pressure level D2.

[0085] Fig. Figure 1c shows the operation of the pneumatic system 10 and, in particular, the compressed air supply system 100 in main consumer mode M1. The moist compressed air D supplied at the main compressed air connection 1.1 is conveyed at the second pressure level D2 via the pneumatic main line 210 towards the main compressed air supply connection 2.1 and is dried by the air dryer 220 along this route. The compressed air supplied at the main compressed air supply connection 2.1 is thus dried compressed air D'.

[0086] Fig. 2a to Fig. Figure 2d shows a second embodiment of the vehicle 1000 and, in particular, of the compressed air supply system 202. Identical or similar components have identical reference numerals, and differences are noted only with regard to the compressed air supply system 201 according to Fig. 1a to Fig. 1c and the compressed air supply system 202 according to Fig. 2a to Fig. Received in 2d.

[0087] The second embodiment differs from the first embodiment according to Fig. 1a to Fig. 1c by the fact that the compressed air supply system 202 has a total of two secondary supply lines 251.2. These include, in addition to the dry high-pressure supply line 271 with the dry switching valve 270, as in Fig. Figures 1a to 1c show a wet high-pressure supply line 281 in which a wet switching valve 280 is arranged.

[0088] Furthermore, the compressed air supply system 202 comprises a total of two compressed air sources Q, in addition to the dry main line section 210.2 serving as compressed air source Q according to Fig. 1a to Fig. 1c The wet main line section 210.1 also forms a compressed air source Q. The wet high-pressure supply line 281 branches off from the wet main line section 210.1 and connects to the primary supply line 251.1.

[0089] The wet switching valve 280 is configured to selectively open the wet high-pressure supply line 281, at least for the unidirectional flow of moist compressed air D into the primary supply line 251.1. A secondary throttle 282 is preferably also arranged in the wet high-pressure supply line 281, which is configured to reduce the pressure of the moist compressed air D flowing through the wet high-pressure supply line 281 and thus lower its relative humidity.

[0090] Fig. Figure 2a shows the pneumatic system 10 in a primary-auxiliary consumer mode SM1, which corresponds to the primary-auxiliary consumer mode according to Fig. 1a corresponds.

[0091] Fig. Figure 2b shows the pneumatic system 10 in the secondary auxiliary consumer mode SM2, where a first variant AM1 of the secondary auxiliary consumer mode SM1 is shown. This corresponds to the one in Fig. 1b shows the first variant AM1 of the secondary auxiliary consumer mode SM2.

[0092] Fig. Figure 2c shows a second variant AM2 of the secondary auxiliary consumer mode SM2, which is made possible by the additional secondary supply line 251.2, namely the wet high-pressure supply line 281. In the second variant AM2 of the secondary auxiliary consumer mode SM2, the moist compressed air D supplied at the main compressed air supply port 1.1 is fed at the second pressure level D2 into the moist main line section 210.1 and from there through the secondary supply line 251.2, designed as a wet high-pressure supply line 281, into the primary supply line 251.1. The wet switching valve 280 is controlled by the control unit 20 such that it allows at least a unidirectional flow of the moist compressed air D from the moist main line section 210.1 into the primary supply line 251.1. The auxiliary compressed air supply port 2.The compressed air provided is therefore moist compressed air D with a third pressure level D3, which corresponds to the second pressure level D2.

[0093] Fig. Figure 2d shows the operation of pneumatic system 10 in main consumer mode M1. This corresponds to the one in Fig. Main consumer mode M1 shown in 1c.

[0094] Fig. 3a to Fig. Figure 3d shows a third embodiment of the vehicle 1000 and, in particular, of the compressed air supply system 203. Identical or similar components have identical reference numerals, and differences are noted only with regard to the compressed air supply system 201 according to Fig. 1a to Fig. 1c and the compressed air supply system 203 according to Fig. 3a to Fig. 3D received.

[0095] The in Fig. 3a to Fig. The third embodiment of the compressed air supply system 203 shown in 3d differs from the one in Fig. 1a to Fig. The first embodiment shown in Figure 1c is distinguished by the fact that, in addition to the dry high-pressure supply line 271, a second primary supply line 251.2, namely a reservoir line 341, is provided. The reservoir line 341 connects to the primary supply line 251.1, preferably between a (second) connection point AV2 of the dry high-pressure supply line 271 and the secondary compressed air supply connection 2.2. A pneumatic element 250.2 in the form of a reservoir switching valve 340 is arranged in the reservoir line 341. The reservoir line 341 is connected to a reservoir 343 as an additional compressed air source Q. In the event that a reservoir shut-off valve 342 releases a reservoir line section 344 between the reservoir 343 and the reservoir line 341, dry compressed air D' from the reservoir 343 can flow via the reservoir line 341 and the reservoir switching valve 340 into the primary supply line 251.1 and thus to the auxiliary compressed air supply connection 2.2 for supplying the auxiliary consumer 400. In this case, reservoir 343 is connected to gallery 313 via reservoir pipe section 344.

[0096] Fig. Figure 3a shows the pneumatic system 10 in primary-auxiliary consumer mode M1, Fig. Figure 3b shows the pneumatic system 10 in the first variant AM1 of the secondary auxiliary consumer mode SM2 and Fig. 3D shows the pneumatic system 10 in main consumer mode M1. This corresponds to the in Fig. 1a to Fig. 1c as well Fig. 2a, Fig. 2b and Fig. 2d shown operating modes, so reference is made to the above description.

[0097] Fig. Figure 3c shows the pneumatic system 10 in a third variant AM3 of the secondary auxiliary consumer mode SM2. The dry compressed air D' stored in reservoir 343 can be the dry compressed air D' supplied at the main compressed air supply port 2.1 with the second pressure level D2 and / or dry compressed air D' returned by the main consumer 300, and in particular the main actuators 320, during venting towards the main compressed air supply port 2.1, which has a venting pressure level D4. This venting pressure level D4 is generally below the second pressure level D2.

[0098] In the third variant AM3 of the secondary auxiliary consumer mode SM2, the dry compressed air D' from reservoir 343 is routed via reservoir line 341, which is connected to reservoir 343, into the primary supply line 251.1 and from there to the auxiliary compressed air supply connection 2.2 to supply the auxiliary consumer 400. The control unit 20 preferably controls the reservoir shut-off valve 242 and the reservoir switching valve 340 in reservoir line 341 such that they allow at least a unidirectional flow of compressed air from reservoir 343 via reservoir line 341 into the primary supply line 251.1.

[0099] Fig. 4a to Fig. Figures 4f show a fourth embodiment of the compressed air supply system 204. Identical or similar components have identical reference numerals, and differences are only noted with regard to the compressed air supply system 203 according to... Fig. 3a to Fig. 3d and the compressed air supply system 204 according to Fig. 4a to Fig. 4e received.

[0100] The fourth embodiment differs from the one in Fig. 3a to Fig. The third embodiment shown in Figure 3d is distinguished by the provision of a total of three compressed air sources Q and a total of three secondary supply lines 251.2. In addition to the dry high-pressure supply line 271 and the reservoir line 341, the secondary supply lines 251.1 also include a gallery return line 311, in which a return switching valve 310 is arranged as a secondary pneumatic switching element 250.2. Alternatively, the pneumatic switching element 250.2 can also be a check valve, as shown in Figure 3d. Fig. 5 shown, act.

[0101] The gallery return line 311 connects to the gallery 313 of the main consumer 300 as the compressed air source Q. The gallery return line 311 connects to the primary supply line 251.1 at a first connection point AV1, and the dry high-pressure supply line 271 connects to the primary supply line 251.1 at a second connection point AV2. A protective valve 240 is preferably arranged between the first connection point AV1 and the second connection point AV2. This valve is configured to prevent backflow of dry compressed air D' from the dry high-pressure supply line 271 into the gallery return line 311 by selectively blocking the primary supply line 251.1. The protective valve 240 can also replace the primary pneumatic switching element 250.1.

[0102] Furthermore, the main consumer 300 includes a switchable gallery valve 350 arranged between the gallery 313 and the main compressed air supply connection 2.1, which is designed as a 2 / 2-way valve and is configured to operate in the Fig. 4a, Fig. 4b, Fig. 4c, Fig. The first switching position S1 shown in 4d blocks the compressed air flow between gallery 313 and the main compressed air supply connection 2.1 and in the Fig. 4e shows the second switching position S2 to allow a bidirectional compressed air flow between gallery 313 and the main compressed air supply connection 2.1.

[0103] The in Fig. 4a, Fig. 4b, Fig. 4c and Fig. The operating modes shown in section 4e correspond to those described in the Fig. The operating modes shown in sections 3a to 3d are described above, and reference is made to their descriptions above. Furthermore, it shows Fig. 4f has an additional reflow operating mode RM.

[0104] Fig. Figure 4d shows the pneumatic system 10 in a fourth variant AM4 of the secondary auxiliary consumer mode SM2. In this case, dry compressed air D' from gallery 313 is used as a compressed air source Q, which is fed into gallery 313 when venting the main consumer 300 and especially the main actuators 320 and which has the venting pressure level D4, via the gallery return line 311 and the return switching valve 310 into the primary supply line 251.1. In the fourth variant AM4 of the secondary auxiliary consumer mode SM2, the control unit 20 controls not only the return switching valve 310 but also the protective valve 240, so that this releases the primary supply line 251.1 and enables the routing of the dry compressed air D' with the third pressure level D3, which corresponds to the venting pressure level D4, to the auxiliary compressed air supply connection 2.2 for supplying the auxiliary consumer 400.Thus, in the event that the pneumatic system 500, in particular the air springs 321, 322, 323, 324, needs to be vented and the auxiliary consumer needs to be supplied with dry compressed air D', compressed air can also be fed from the gallery return line 311 into the primary supply line 251.1 via the return switching valve 310.

[0105] Fig. Figure 4e shows the pneumatic system 10 in main consumer mode M1, as in relation to Fig. Explained in 3D.

[0106] Fig. Figure 4f shows another operating mode, the so-called reflow operating mode RM. In this mode, the pneumatic system 10 and the compressed air supply system 204, according to the fourth embodiment, also enable the charging of the second compressor stage 120 with dry compressed air D' at the venting pressure level D4. The protective valve 240 blocks the primary supply line 251.1, so that the compressed air D' can flow via the gallery return line 311, which is released by the return valve 310, exclusively into the primary supply line 251.1 towards the secondary compressed air connection 1.2 or the pipe section 140. To charge the second compressor stage 120, the control unit 20 controls the primary pneumatic switching element 250.1 to release the primary supply line 251.1 and furthermore the compressor switching valve 290 to release the pipe section 140, so that the dry compressed air D' with the venting pressure level D4 can flow from gallery 313 to the second inlet 121 of the second compressor stage 120. Fig. Figure 5 shows a fifth embodiment of the compressed air supply system 205. Identical or similar components have identical reference numerals, and differences are only noted with regard to the compressed air supply system 201 according to... Fig. 1a to Fig. 1c and the compressed air supply system 205 according to Fig. 5 received.

[0107] In the fifth embodiment, the secondary pneumatic switching element 250.2 is designed as a dry switching valve in the form of a check valve 270'. The dry check valve 270' allows, upon exceeding an opening pressure, an exclusively unidirectional flow of dry compressed air D' from the dry main line section 210.2 into the primary supply line 251.1 via the dry high-pressure supply line 271. The pneumatic system 10 according to the fifth embodiment can be used in all of the configurations described above. Fig. 1a to Fig. The operating modes shown in 1c can be used.

[0108] Fig. Figure 6 shows a second embodiment of the pneumatic system 11 and, in particular, of the main consumer. Identical or similar components have identical reference numerals, and differences are noted only with regard to the pneumatic system 10 according to... Fig. 3a to Fig. 3d and the pneumatic system 11 according to Fig. 6 received.

[0109] The reservoir shut-off valve is located in the Fig. In the embodiment shown in Figure 6, the reservoir is designed as a check valve 342'. Thus, the reservoir 343 is exclusively designed to be filled with dry compressed air D' via the gallery 313.

[0110] Fig. Figure 7 shows a seventh embodiment of the pneumatic system 12. Identical or similar components have identical reference numerals, and differences are only noted with regard to the pneumatic system 10 according to Fig. 1a to Fig. 1c and of the pneumatic system 12 according to Fig. 7 received.

[0111] The seventh embodiment differs from the first embodiment according to Fig. 1a to Fig. 1c by the fact that the main consumer 300 is designed as a brake system 302 and furthermore by the fact that the auxiliary consumer 400 is designed as a signal horn 402 or tire inflation system 403.

[0112] Fig. Figure 8 shows a method 2000 for controlling a compressed air distribution in a pneumatic system 10, as it Fig. 1a to Fig. Show 7.

[0113] In a first step 2100, the process 2000 comprises the compression of compressed air D to a first pressure level D1 with a first compressor stage 110 and to a second pressure level D2 with a second compressor stage 120. The second pressure level D2 is higher than the first pressure level D1.

[0114] In a second step 2200, the process 2000 includes the provision of moist compressed air D with the second pressure level D2 at a main compressed air connection 1.1.

[0115] In a third step 2300, the method 2000 further comprises guiding the moist compressed air D provided at the main compressed air connection 1.1 with the second pressure level D2 via a pneumatic main line 210, wherein the moist compressed air D with the second pressure level D2 is dried by an air dryer 220 arranged in the pneumatic main line 210.

[0116] In a fourth step 2400, moist compressed air D is supplied at the first pressure level D1 at a secondary compressed air connection 1.2.

[0117] Furthermore, in a fifth step 2500, the method 2000 comprises the selective operation of the pneumatic system 10 in different consumer modes. The fifth step comprises, in a first sub-step 2510, the selective operation of the pneumatic system 10 in a main consumer mode M1, in a second sub-step 2520, the selective operation of the pneumatic system 10 in a primary secondary consumer mode SM1, and in a third sub-step 2530, the selective operation of the pneumatic system 10 in at least one secondary secondary consumer mode SM2. The corresponding consumer modes are described in detail with regard to the Fig. 1a to 4e described. The third sub-step 2530, namely the selective operation of the pneumatic system 10 in at least one secondary auxiliary consumer mode SM2, preferably comprises various variants which can be carried out alternatively or cumulatively. These variants relate to the first variant AM1 to the fourth variant AM4 of the secondary auxiliary consumer mode SM2, which, with respect to the Fig. 1a to 4e are described in detail. Preferably, the method further includes operation in reflow mode, as described in Fig. 4f shown.

[0118] The method 2000 preferably includes, within the second sub-step 2520, i.e., the operation of the pneumatic system 10 in primary-auxiliary consumer mode SM1, the control 2521 of a primary pneumatic switching element 250.1 arranged in the primary supply line 251.1 for the selective release of the primary supply line 251.1.

[0119] Furthermore, the second sub-step 2520, i.e., the operation of the pneumatic system in primary-auxiliary consumer mode SM1, includes the actuation 2522 of a compressor switching valve 290 to selectively block the line section 140 between the first compressor stage and the second compressor stage.

[0120] Further preferably, the third sub-step 2530, i.e., operating the pneumatic system in at least one secondary auxiliary consumer mode SM2, comprises controlling 2531 the secondary pneumatic switching element 250.2 arranged in the secondary supply line 251.2 for selectively releasing the secondary supply line 251.2. The secondary pneumatic switching element 250.2 controlled according to the method can be one, several, or all of the elements related to the Fig. 1a to 7 illustrate secondary pneumatic switching elements 250.2.

[0121] In summary, the invention relates to a compressed air supply system 100, which comprises: - a compressor 101 with a first and second compressor stage 110, 120 for compressing compressed air D to two different pressure levels D1, D2, - a compressed air supply system 201, 202, 203, 204, 205 with a main compressed air connection 1.1 connected to the compressor 101, a pneumatic main line 210 with an air dryer 220 for drying and conveying compressed air D from the main compressed air connection to a main compressed air supply connection 2.1, a supply line 251 for conveying compressed air D to a secondary compressed air supply connection 2.2 with a switchable pneumatic element 250 for enabling and disabling the supply line 251. The invention proposes that the main compressed air connection is connected to the second compressor stage 120 and that the compressed air supply system 201, 202, 203, 204, 205 has a secondary compressed air connection 1.2 connected to the first compressor stage 110, wherein the supply line 251 conveys compressed air D from the Auxiliary compressed air connection 1.2 leads to the auxiliary compressed air supply connection 2.2, and at least one to the primary supply line 251.1. A subsequent secondary supply line 251.2 with a secondary pneumatic switching element 250.2 for connection to a compressed air source Q supplied by the main compressed air connection 1.1 for providing compressed air D, D' with a third pressure level D3 that is higher than the first pressure level, wherein the secondary pneumatic switching element 250.2 allows at least one unidirectional compressed air flow from the compressed air source Q into the primary supply line 251.1. The invention further relates to a pneumatic system 10, 11, 12, a vehicle 1000 and an operating method 2000.

[0122] Within the scope of the invention, for the first time, multiple, and in particular all, compressed air consumer systems can be modularly interconnected and thus connected to a single, central compressed air supply system in a demand-oriented and energy-efficient manner. This compressed air supply system enables the alternative availability of various functions, such as pressure, humidity, air volume, and the like. All functions of known open and closed pneumatic systems, such as air spring systems, are covered, including reservoir filling, overflow filling from the reservoir into air spring bellows, boost and reflow functions, etc.

[0123] The basic idea of ​​the invention is therefore to enable the already known functions of a pneumatic system for a vehicle, such as the compressed air preparation for the pneumatic system, for example for the air springs 321, 322, 323, 324, the intermediate storage of compressed air in a reservoir, the reflow operation and the charging of the compressor in a known manner, and at the same time to enable the demand-based supply of compressed air to an auxiliary consumer having different pressure levels and moisture contents.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] Any reference numerals in the claims are not to be understood as limiting the scope of application. Reference symbol list (part of the description) 1.1 Main compressed air connection 1.2 Auxiliary compressed air connection 2.1 Main compressed air supply connection 2.2 (first) secondary compressed air supply connection 2.3 Second auxiliary compressed air supply connection 0 / 3 combined intake and exhaust port 10, 11, 12 pneumatic system 100 compressed air supply system 101 compressors 110 first compressor stage 111 first admission 112 first outlet 120 second compressor stage 121 second entrance 122 second outlet 130 engine 140 cable section 201-206 Compressed air supply system 210 Pneumatic main line 210.1 damp main line section 210.2 dry main line section 213 Intake pipe 216 Vent line 220 air dryers 221 Air dryer inlet 230 throttle 240 protective valve 250 pneumatic elements 250.1 primary pneumatic switching element 250.2 secondary pneumatic switching element 251.1 primary supply line 251.2 secondary supply line 254 second supply line 255 second switchable pneumatic element 260 Vent valve arrangement 261 Relay valve 262 Venting compressor pilot valve 270, 270' Dry switching valve 271 Dry high-pressure supply line 280 Wet switching valve 281 Wet high-pressure supply line 282 Subthrottle 290 Compressor switching valve 291 Electrically operated 2 / 2-way compressor valve 292 pneumatically actuated 2 / 2-way compressor valve 293 Compressor-compressor pilot valve 294 Supply line 295 Valve vent line 296 Actuating line 300 main consumers 301 Air suspension system 302 Brake system 310 Return switching valve 311 Gallery Return Line 313 Gallery 320 main actuators 321-324 Air springs 330 Main consumer valve arrangement 331-334 Main consumer switching valves 340 Reservoir switching valve 341 Reservoir line 342, 342' reservoir check valve 343 Reservoir 344 Reservoir pipeline section 350 gallery valve 360 pressure sensor, 400 auxiliary consumers 401 Sensor cleaning device 410 Supply line 420 auxiliary actuators 430 auxiliary actuators 500 secondary consumers 501 Tire inflation system 502 Signal horn 1000 vehicles 1100 passenger cars 2000 procedures 2100 Compressing compressed air 2200 Supplying compressed air at the main compressed air connection 2300 Routing the compressed air from the main compressed air connection to the main compressed air supply connection 2400 Supply of compressed air at the secondary compressed air connection 2500 selective operation of the pneumatic system 2510 in a main consumer mode 2520 in a primary-secondary user mode 2521 Controlling a primary pneumatic switching element 2522 Controlling a compressor switching valve 2530 in a secondary auxiliary user mode 2531 Controlling the secondary pneumatic switching element A surroundings D moist compressed air D' dry compressed air D1 first pressure level D2 second pressure level D3 third pressure level DS control pressure DG Gallery Print Q Compressed air source G closed compressed air supply O open compressed air supply E Venting branch Z Junction ZB Boost junction AV1 first junction AV2 second junction B Filling direction S1 first switching position S2 first switching position SP Locking Position FP Release Position M1 Main Consumer Mode SM1 Primary-Auxiliary User Mode SM2 Secondary Auxiliary User Mode AM1 first secondary auxiliary consumer mode AM2 second secondary auxiliary consumer mode AM3 third secondary auxiliary consumer mode AM4 fourth secondary auxiliary consumer mode RM Reflow operating mode QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102017010772 A1

[0009] WO 0176898A1

[0011]

Claims

[1] Compressed air supply system (100) for a pneumatic system (10, 11, 12) of a vehicle (1000), in particular according to one of the preceding claims, comprising: comprehensive: - a compressor (100) with a first compressor stage (110) for compressing compressed air (D) to a first pressure level (D1) and a second compressor stage (120) for compressing the compressed air (D) to a second pressure level (D2), wherein the second pressure level (D2) is higher than the first pressure level (D1), - a compressed air supply system (201, 202, 203, 204, 205) with a main compressed air connection (1.1) for connection to the compressor (100), a main compressed air supply connection (2.1) and a secondary compressed air supply connection (2.2) for supplying compressed air (D), a pneumatic main line (210) for conveying compressed air (D) from the main compressed air connection (1.1) to the main compressed air supply connection (2.1), an air dryer (220) arranged in the pneumatic main line (210) for drying the compressed air conveyed to the main compressed air supply connection (2.1), a primary supply line (251.1) for conveying compressed air (D) to the secondary compressed air supply connection (2.2) and a primary pneumatic switching element (250.1) arranged in the primary supply line (251.1) for Selective enabling and disabling of the primary supply line (251.1), wherein the main compressed air supply connection (2.1) is set up for connecting a main consumer (300) and the secondary compressed air supply connection (2.2) is set up for connecting a secondary consumer (400), characterized by , that the compressed air supply system (201, 202, 203, 204, 205) has an auxiliary compressed air connection (1.2) connected to the first compressor stage (110), and the primary supply line (251.1) is designed to carry compressed air (D) from the auxiliary compressed air connection (1.2) to the auxiliary compressed air supply connection (2.2), and the auxiliary compressed air supply connection (2.2) is designed to provide compressed air (D) at the first pressure level (D1), and wherein the main compressed air connection (1.1) is connected to the second compressor stage (120) and the main compressed air supply connection (2.1) is set up to provide compressed air (D) at the second pressure level (D2), and that the compressed air supply system (201, 202, 203, 204, 205) has at least one secondary supply line (251.2) connected to the primary supply line (251.1), which is configured to connect to a compressed air source (Q) supplied via the main compressed air connection (1.1) for the provision of compressed air (D, D') at a third pressure level (D3) higher than the first pressure level, and wherein the secondary supply line (251.2) has a pneumatic switching element (250.2) configured to allow at least one unidirectional compressed air flow from the compressed air source (Q) into the primary supply line (251.1). [2] Compressed air supply system (100) according to claim 1, wherein the compressed air source (Q) is a dry main line section (210.2) of the pneumatic main line (210) extending between an air dryer outlet (220.2) of the air dryer (220) and the main compressed air supply port (2.1), and the third pressure level (D3) corresponds to the second pressure level (D2), wherein the secondary supply line (271) is a dry high-pressure supply line (271) branching off from the dry main line section (210.2) for carrying dry compressed air (D') at the third pressure level (D3). [3] Compressed air supply system (100) according to any one of the preceding claims, wherein the compressed air source (Q) is a moist main line section (210.1) of the pneumatic main line (210) extending between the main compressed air connection (1.1) and an air dryer inlet (220.1) of the air dryer (220), and the third pressure level (D3) corresponds to the second pressure level (D2), wherein the secondary supply line (251.2) is a wet high-pressure supply line (281) branching off from the wet main line section (210.2) for carrying moist compressed air (D) at the third pressure level (D3). [4] Compressed air supply system (100) according to claim 3, wherein the compressed air supply system (201) has a secondary throttle (282) arranged in the wet high-pressure supply line (281) which is configured to expand the moist compressed air (D) with the third pressure level (D3). [5] Compressed air supply system (100) according to any one of the preceding claims, wherein the compressed air source (Q) is a reservoir (343) connectable to the main compressed air supply port (2.1), and the third pressure level (D3) corresponds to the second pressure level (D2) provided at the main compressed air supply port (2.1) or a venting pressure level (D4) of the dry compressed air (D') returned from the main consumer (300) towards the main compressed air supply port (2.1), wherein the secondary supply line (251.2) is a reservoir line (341) connectable to the reservoir (343) for carrying dry compressed air (D') to the third pressure level (D3). [6] Compressed air supply system (100) according to any one of the preceding claims, wherein the compressed air source (Q) is a gallery (313) of the main consumer (30) connectable to the main compressed air supply port (2.1), and the third pressure level (D3) corresponds to a venting pressure level (D4) of the dry compressed air (D') returned from the main consumer (300) towards the compressed air supply port (2.2), wherein the secondary supply line (251.2) is a gallery return line (311) connectable to the gallery (313) for carrying dry compressed air (D') at the third pressure level (D3). [7] Compressed air supply system (100) according to at least one of claims 2 to 6, wherein the secondary pneumatic switching element (250.2) comprises at least one of the following: - a dry switching valve (270, 270') arranged in the dry high-pressure supply line (271), which is configured to allow at least a unidirectional flow of dried compressed air (D') at the third pressure level (D3) from the dry main line section (210.2) into the primary supply line (251.1), - a wet switching valve (280) arranged in the wet high-pressure supply line (271), which is configured to allow at least a unidirectional flow of moist compressed air (D) at the third pressure level (D3) from the moist main line section (210.1) into the primary supply line (251.1), - a reservoir switching valve (340) arranged in the reservoir line (341), which is configured to allow at least a unidirectional flow of dry compressed air (D') at the third pressure level (D3) from the reservoir (343) into the primary supply line (251.1), - a return switching valve (310) arranged in the gallery return line (311) which is configured to allow at least a unidirectional flow of dry compressed air (D') at the third pressure level (D3) from the gallery (313) into the primary supply line (251.1). [8] Compressed air supply system (100) according to any one of the preceding claims, wherein the first compressor stage (110) has a first inlet (111) and a first outlet (112) connected to an intake port (0 / 3) and the second compressor stage (120) has a second outlet (122) connected to the main pneumatic line (210) and a second inlet (121) connected to the first outlet (112) via a line section (140), wherein the compressed air supply system (201) further comprises a compressor switching valve (290) for selectively enabling and disabling the pipe section (140). [9] Pneumatic system (10, 11, 12) for a vehicle (1000), in particular a passenger car (1100), comprising: - a compressed air supply system (100) according to any one of claims 1 to 8, - a main consumer (300) connected to the main compressed air supply connection (2.1), and - an auxiliary consumer (400) connected to the auxiliary compressed air supply connection (2.2). [10] Pneumatic system (11) according to claim 9, wherein the main consumer (300) comprises the reservoir (343) which is connected to the main compressed air supply port (2.1) and the reservoir line (341) by at least one reservoir line section (344), wherein the main consumer (300) further comprises a reservoir shut-off valve (342, 342') which is configured to allow at least a unidirectional flow of dried compressed air (D') from the main compressed air supply port (2.1) into the reservoir (343) and to at least selectively shut off the reservoir line section (344) for a flow of dry compressed air (D') from the reservoir line (341) and / or the reservoir (343). [11] Vehicle (1000), in particular passenger car (1100), with a pneumatic system (10) according to one of claims 9 or 10. [12] Method (2000) for controlling a compressed air distribution in a pneumatic system (10), in particular in a pneumatic system (10) according to one of claims 9 or 10, comprising the steps: - Compression (2100) of compressed air (D) to a first pressure level (D1) with a first compressor stage (110) and to a second pressure level (D2) with a second compressor stage (120), wherein the second pressure level (D2) is higher than the first pressure level (D1), - Providing (2200) moist compressed air (D) at the second pressure level (D2) at a main compressed air connection (1.1), - Guiding (2300) the moist compressed air (D) supplied at the main compressed air connection (1.1) with the second pressure level (D2) via a pneumatic main line (210), wherein the moist compressed air (D) with the second pressure level (D2) is dried by an air dryer (220) arranged in the pneumatic main line (210), - Providing (2400) moist compressed air (D) at the first pressure level (D1) at a secondary compressed air connection (1.2), - Selective operation (2500, 2510, 2520, 2530) of the pneumatic system (10) in a main consumer mode (M1), a primary auxiliary consumer mode (SM1) and at least one secondary auxiliary consumer mode (SM2), wherein in the main consumer mode (M1) the moist compressed air (D) supplied at the main compressed air connection (1.1) with the second pressure level (D2) is guided via the main pneumatic line (210) towards a main compressed air supply connection (2.1), is dried by an air dryer (220) arranged in the main pneumatic line (210) and is supplied as dried compressed air (D') with the second pressure level (D2) and in the secondary auxiliary consumption mode (SM2) compressed air (D) is supplied at an auxiliary compressed air supply connection (2.2), wherein in the primary auxiliary consumer mode (SM1) the moist compressed air (D) supplied at the auxiliary compressed air connection (1.2) with the first pressure level (D2) is routed via the primary supply line (251.1) to an auxiliary compressed air supply connection (2.2) and supplied as moist compressed air (D) with the first pressure level (D1), and wherein in the secondary auxiliary consumer mode (SM2) compressed air (D, D') with a third pressure level (D3) which is higher than the first pressure level (D1) is supplied from a compressed air source (Q) via at least one secondary supply line (251.2) connected to the primary supply line (251.1) and a secondary pneumatic switching element (250.2) arranged in the primary supply line (251.1) and is provided at the auxiliary compressed air supply connection (2.2). [13] Method (2000) according to claim 12, wherein the at least one secondary auxiliary consumer mode (SM2) comprises one, several or all of the following: - a first secondary auxiliary consumer mode (AM1) in which the moist compressed air (D) supplied at the main compressed air port (1.1) at the second pressure level (D2) is guided via the pneumatic main line (210) towards a main compressed air supply port (2.1), is dried by an air dryer (220) arranged in the pneumatic main line (210), wherein the compressed air source (Q) is a dry main line section (210.2) of the pneumatic main line (210) extending between an air dryer outlet (220.2) of the air dryer (220) and the main compressed air supply port (2.1), and the third pressure level (D3) corresponds to the second pressure level (D2), and wherein the secondary supply line (271) is a dry high-pressure supply line (271) branching off from the dry main line section (210.2) for carrying dry compressed air (D') with the third pressure level (D3) is, - a second secondary auxiliary consumer mode (AM2) in which the moist compressed air (D) supplied at the main compressed air port (1.1) at the second pressure level (D2) is routed via the pneumatic main line (210) towards a main compressed air supply port (2.1), wherein the compressed air source (Q) is a moist main line section (210.1) of the pneumatic main line (210) extending between the main compressed air port (1.1) and an air dryer inlet (220.1) of the air dryer (220), and the third pressure level (D3) corresponds to the second pressure level (D2), and wherein the secondary supply line (251.2) is a wet high-pressure supply line (281) branching off from the moist main line section (210.2) for carrying dry compressed air (D') at the third pressure level (D3), - a third secondary auxiliary consumer mode (AM3), wherein the compressed air source (Q) is a reservoir (343) connectable to the main compressed air supply port (2.1), and the dry compressed air (D') supplied at the main compressed air supply port (2.1) at the second pressure level (D2) and / or dry compressed air (D') returned from a main consumer (300) towards the main compressed air supply port (2.1) at a venting pressure level (D4) is stored in the reservoir (343), wherein the third pressure level (D3) corresponds to the second pressure level (D2) supplied at the main compressed air supply port (2.1) or the venting pressure level (D4), and wherein the secondary supply line (251.2) is a reservoir line (341) connectable to the reservoir (343) for supplying dry compressed air (D') at the third pressure level (D3), - a fourth secondary auxiliary consumer mode (AM4), wherein the compressed air source (Q) is a gallery (313) of the main consumer (30) connectable to the main compressed air supply port (2.1), and dry compressed air (D') with a venting pressure level (D4) is fed into the gallery (313) for venting the main consumer (300), the third pressure level (D3) corresponding to the venting pressure level (D4), and the secondary supply line (251.2) is a gallery return line (311) connectable to the gallery (313) for feeding dry compressed air (D') with the third pressure level (D3). [14] Method (2000) according to claim 12 or 13, wherein the operation (2520) of the pneumatic system (10) in primary auxiliary mode (SM1) comprises actuating (2521) a primary pneumatic switching element (250.1) arranged in the primary supply line (251.1) for selective release of the primary supply line (251.1), and / or wherein the operation (2530) of the pneumatic system (10) in secondary auxiliary mode (SM2) comprises actuating (2531) the secondary pneumatic switching element (250.2) arranged in the secondary supply line (251.2) for selective release of the secondary supply line (251.2). [15] Method (2000) according to claim 14, wherein the actuation (2531) of the secondary pneumatic switching element (250.2) arranged in the secondary supply line (251.2) for selectively releasing the secondary supply line (251.2) comprises one, several or all of the following: - Actuating the secondary pneumatic switching element (250.2), which is designed as a dry switching valve (270, 270') arranged in the dry high-pressure supply line (271), to allow a unidirectional flow of dried compressed air (D') at the third pressure level (D3) from the dry main line section (210.2) into the primary supply line (251.1), - Controlling the secondary pneumatic switching element (250.2), which is designed as a wet switching valve (280) arranged in the wet high-pressure supply line (271), to allow a unidirectional flow of moist compressed air (D) at the third pressure level (D3) from the moist main line section (210.1) into the primary supply line (251.1), - Actuating the secondary pneumatic switching element (250.2), which is designed as a reservoir switching valve (340) arranged in the reservoir line (341), to allow a unidirectional flow of dry compressed air (D') at the third pressure level (D3) from the reservoir (343) into the primary supply line (251.1), and - Controlling the secondary pneumatic switching element (250.2), which is a return switching valve (310) arranged in the gallery return line (311), to allow a unidirectional flow of dry compressed air (D') at the third pressure level (D3) from the gallery (313) into the primary supply line (251.1). [16] Method (2000) according to claim one of claims 13 to 15, wherein the first compressor stage (110) has a first inlet (111) and a first outlet (112) connected to an intake port (0 / 3) and the second compressor stage (120) has a second outlet (122) connected to the main pneumatic line (210) and a second inlet (121) connected to the first outlet (112) via a line section (140), and wherein the operation (2520) of the pneumatic system (10) in primary auxiliary consumer mode (SM1) includes the actuation (2522) of a compressor switching valve (290) to selectively block the pipe section (140). [17] Control unit (20) for controlling a pneumatic system (10) of a vehicle (1000), in particular a passenger car (1100), characterized by, that the control unit (20) is configured for selective operation (2400, 2410, 2420, 2430) of the pneumatic system (10, 11, 12) in a main consumer mode (M1), a primary auxiliary consumer mode (SM1) and at least one secondary auxiliary consumer mode (SM2) in a method according to one of claims 13 to 16.

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