Compressed air generating device and method for operating same

Abstract

The invention relates to a compressed air generating device (2.9), with an open-loop and closed-loop control unit (28), with at least one open-loop and closed-loop controllable electric motor (24), with at least one air compressor (16; 18) which can be driven by the electric motor, with an air inlet (8), via which ambient air (L) can be sucked into the at least one air compressor, with at least one air cooler (20, 22) which is connected or can be connected to the outlet of the at least one air compressor, with an air dryer (40), the inlet of which is connected to the outlet of the at least one air cooler, with a coolant inlet opening (12), via which a liquid coolant can be fed to the at least one air cooler and to further components of the compressed air generating device, and with a coolant outlet opening (14), via which heated coolant can be discharged from the compressed air generating device. In order for the compressed air generating device to be of as compact and inexpensive configuration as possible in terms of production and of as variable configuration as possible with regard to cooling thereof, it is provided, inter alia, that that air cooler (22) which is arranged as the last air cooler upstream of the air dryer (40) in the flow direction of the compressed air can be flowed through by the coolant first, as viewed in the flow direction of the coolant. Moreover, three external cooling devices (82, 120, 122) which, depending on the cooling requirement, can be utilized alternatively or additively in order to cool the generated compressed air and the existing components can be connected to the compressed air generating device. The invention also relates to a method for operating this compressed air generating device.

Description

[0001] Compressed air generating device and method for operating the same

[0002] The invention relates to a compressed air generating device, comprising a control and regulating unit, at least one controllable and regulatable electric motor, at least one air compressor driven by the electric motor, an air inlet through which ambient air can be sucked into the at least one air compressor, at least one air cooler which is or can be connected to the outlet of the at least one air compressor, an air dryer whose inlet is connected to the outlet of the at least one air cooler, a coolant inlet opening through which a liquid coolant can be supplied to the at least one air cooler and other components of the compressed air generating device, and a coolant outlet opening through which heated coolant can be discharged from the compressed air generating device. The invention also relates to a method for operating such a compressed air generating device.

[0003] Electrically driven compressors for generating compressed air in vehicles are already known in various embodiments and are described, for example, in DE 10 2018 139 058 A1, DE 10 2013 003 513 A1 and EP 3 516 218 B1. EP 3 331 738 B1 discloses a compressed air generating device for a vehicle with a piston compressor and two compression stages. The cylinder chambers of the two compression stages are connected to one another by a connecting line through which the compressed air generated in the first compression stage can be fed to the second compression stage. During operation of the piston compressor, the ambient air pressure in the first compression stage is increased with the aid of a backpressure building up in the subsequent connecting line. An intercooler is arranged in the connecting line between the two compression stages and serves to cool the air heated during compression in the first compression stage.The pressure of the compressed air in the connecting line drops.

[0004] The intercooler thus increases the efficiency of the second compression stage. Furthermore, additional devices for processing the air used, such as additional cooling devices or air drying devices, can be arranged before or after the first compression stage. One disadvantage is that the described compressor is designed as a reciprocating piston compressor, which disadvantageously requires a lubricant. Furthermore, the design of the cooling system is not further described.

[0005] Furthermore, DE 10 2004 051 435 B3 discloses a system for generating dry compressed air, which comprises a cooled compressor for drawing in and compressing ambient air. A cooler is arranged downstream of the compressor in the direction of compressed air flow, which serves to cool the generated compressed air. The cooling effect of the cooler is achieved by means of a fan and water droplets directed onto the surface of the cooler, where they evaporate and thereby remove heat from the cooler and indirectly from the compressed air. An air dryer is arranged downstream of the cooler. This dryer contains a desiccant that removes air humidity from the compressed air, thereby lowering the dew point of this compressed air. The compressed air dried in this way has a humidity of less than 35% at the outlet of the air dryer, which should be sufficient to protect devices subsequently supplied with this compressed air from corrosion or freezing due to the formation of water ice.

[0006] Furthermore, DE 44 45 972 02 discloses a compressor system for generating dry compressed air. An air-cooled radiator serves to cool the compressed air generated by a compressor. A water separator is arranged downstream of the radiator, which removes water droplets from the compressed air that form through condensation during cooling. Since the compressed air is not yet sufficiently dry to prevent freezing at low temperatures when used in pressure medium consumers, an air dryer is arranged downstream of the water separator, in which the compressed air is further dried.

[0007] Furthermore, from the applicant's unpublished DE 10 2021 121 424.6, a compressed air generation device is known which has an electric motor that can drive two air compressors arranged in series. During operation of the compressed air generation device, ambient air is sucked in and compressed by the first air compressor. From there, the pre-compressed compressed air is fed to the second air compressor via a check valve, an intercooler, and a switching valve. In the second air compressor, the pre-compressed compressed air is further compressed and then passed on to compressed air consumers via an aftercooler or another switching valve. The intercooler and the aftercooler are cooled by a liquid coolant and serve to cool the compressed air generated by the air compressors.The liquid coolant originates, for example, from a vehicle's cooling circuit and, in the compressed air generation device, first supplies a cooling device of the electric motor, then the intercooler, and then a cooling device of the first air compressor. From there, the coolant flows to the aftercooler and then to a cooling device of the second air compressor before being returned to the vehicle's cooling circuit. An air dryer is neither shown nor described in this compressed air generation device.

[0008] Furthermore, US 2010 / 0 303 658 A1 discloses a water-cooled and oil-free two-stage air compressor, which has a water-cooled intercooler arranged between a first air compressor and a second air compressor with respect to the air flow. The air compressed by the first air compressor is cooled by the intercooler, and the air compressed by the second air compressor is cooled by an aftercooler, whose cooling water inlet is hydraulically connected to the cooling water outlet of the intercooler.

[0009] Finally, DE 11 2015 006 955 T5 discloses a compressed air supply system for locomotives and a method for operating the same. The air drawn in and compressed by a compressor is cooled in an air cooler and then fed to a first compressed air reservoir. From this first compressed air reservoir, the compressed air flows via a check valve closing in the return flow direction to a pre-filter, which has a drainage valve. After liquid and aerosolized water has been separated from the compressed air in the pre-filter, the compressed air flows to an air dryer. A temperature sensor located at the air flow inlet of the air dryer or in its immediate vicinity is connected to a control unit via a sensor line. The temperature sensor can measure the actual temperature of the compressed air flowing into the air dryer and provide this measured value to the control unit.Based on the saturation partial pressure of water vapor at the measured actual temperature of the compressed air, the control unit can calculate a suitable purge cycle time for the drain valve and control its operation to remove the water accumulated in the pre-filter.

[0010] The drying agent in the air dryer of such compressed air generation devices must also be repeatedly freed of the moisture that has accumulated there, because if the drying agent's moisture absorption capacity is saturated, it is no longer able to function properly. To remove this moisture from the air dryer, a known method is to recirculate the dry compressed air generated by the compressed air generation device and stored in a pressure fluid reservoir back through the air dryer in a so-called regeneration process. The dry compressed air absorbs moisture from the air dryer's drying agent and transports it out into the environment surrounding the compressed air generation device.Since these regeneration processes consume dried compressed air, which in a motor vehicle is actually required for operating brake actuators and / or air spring bellows, for example, additional compressor operating times are necessary to ensure sufficient compressed air is available for the regeneration processes. However, this entails additional energy consumption, which increases the operating costs of a motor vehicle, for example, and ultimately releases environmentally harmful CO2 into the atmosphere through the generation of electrical energy for the electric motor.

[0011] Against this background, the invention is based on the object of presenting a compressed air generation device comprising a compressor, a liquid cooling system, and an air dryer, which is compact and inexpensive to manufacture. Furthermore, this compressed air generation device should enable lower consumption of dried compressed air during regeneration of a drying agent of the air dryer than with known compressed air generation devices. Furthermore, the compressed air generation device should be coolable by more than one external cooling device. Finally, the necessary cooling requirement and the required regeneration compressed air volume should be determinable by a method, and the compressed air generation device should be controlled and / or regulated accordingly.

[0012] This object is achieved with a compressed air generating device having the features of claim 1. An independent method claim defines a method for operating such a compressed air generating device. Advantageous embodiments and further developments are recited in the respective dependent claims.

[0013] Accordingly, the invention initially relates to a compressed air generating device, with a control and regulating unit, with at least one controllable and regulatable electric motor, with at least one air compressor that can be driven by the electric motor, with an air inlet through which ambient air can be sucked into the at least one air compressor, with at least one air cooler that is or can be connected to the outlet of the at least one air compressor, with an air dryer whose inlet is connected to the outlet of the at least one air cooler, with a coolant inlet opening through which a liquid coolant can be supplied to the at least one air cooler and other components of the compressed air generating device, and with a coolant outlet opening through which heated coolant can be discharged from the compressed air generating device.

[0014] In order to solve the device-related problem with regard to the need for the smallest possible regeneration pressure volume for a regeneration process of the drying agent of the air dryer, it is provided that the air cooler which is arranged as the last air cooler in front of the air dryer in the flow direction of the compressed air is the first through which the coolant can flow, as seen in the flow direction of the coolant.

[0015] In a departure from previously known designs, the still relatively cold liquid coolant first flows through an aftercooler, which is located directly upstream of the air dryer in the direction of compressed air flow. This cools the compressed air as much as possible, so that some of the humidity contained in the compressed air precipitates in the form of small water droplets before it reaches the air dryer. This water is then removed from the compressed air, for example, by a water separator in the aftercooler before it reaches the air dryer.A small amount of condensed water droplets can also be carried along by the relatively cooled compressed air through a short compressed air line to the air dryer, where these water droplets collect in the inlet collection area and are removed during the next regeneration process with the regeneration compressed air flowing out of the air dryer. Because a relatively large amount of moisture is removed from the compressed air before it reaches the air dryer's desiccant, the air dryer is subsequently required less intensively to dry the compressed air. As a result, a regeneration process on the air dryer, which consumes dried compressed air, needs to be performed less frequently.

[0016] According to a more detailed development of the compressed air generation device just described and having the features of the invention, said device is equipped with the following: a control and regulating device, an electric motor, two air compressors that can be driven by the electric motor and operate one after the other, an air inlet through which ambient air can be sucked in by means of the first air compressor, a first air cooler designed and arranged as an intercooler and a second air cooler designed and arranged as an aftercooler, wherein the inlet of the intercooler is or can be connected pneumatically to the outlet of the first air compressor, wherein the outlet of the intercooler is or can be connected pneumatically to the inlet of the second air compressor, and wherein the outlet of the second air compressor is or can be connected pneumatically to the inlet of the aftercooler, an air dryer,whose inlet is pneumatically connected to the outlet of the aftercooler, and with a coolant inlet opening, through which a liquid coolant can be supplied to the intercooler, the aftercooler, and other components of the compressed air generation device, as well as with a coolant outlet opening, through which heated coolant can be discharged. This compressed air generation device is also characterized, to achieve the aforementioned advantages, in that the aftercooler, which is arranged as the last air cooler upstream of the air dryer in the direction of flow of the compressed air, is the first through which the coolant can flow, as seen in the direction of flow of the coolant. In order to further cool the compressed air to be dried in the air dryer before it enters the drying agent, according to another development of the coolant circuit,that a coolant inlet of the aftercooler is connected to the coolant inlet opening of the compressed air generation device, that a coolant outlet of the aftercooler is connected to a coolant inlet of the intercooler, that a coolant outlet of the intercooler is connected to a coolant inlet of a dryer module cooler, that a coolant outlet of the dryer module cooler is connected to a coolant inlet of the electric motor, that a coolant outlet of the electric motor is connected to a coolant inlet of the second air compressor, that a coolant outlet of the second air compressor is connected to a coolant inlet of an inverter, which serves to control and regulate the electric motor by means of the control and regulation device, that a coolant outlet of the inverter is connected to a coolant inlet of the first air compressor,and that a coolant outlet of the first air compressor is connected to the coolant outlet opening.,

[0017] The dryer module cooler is designed and arranged in such a way that at least components of the air dryer can be cooled. It can also be provided that a multi-circuit protection valve arranged close to the air cooler is structurally integrated into the dryer module cooler or can be cooled by it. The described design has the advantage that components of the air dryer, preferably its housing, are cooled, whereby the compressed air supplied to the air dryer can be further cooled even before it enters the desiccant. This allows humidity to condense out of the compressed air as water and be removed, so to speak, at the last possible device-related opportunity.

[0018] In order to further improve the use of the compressed air generating device having the features of the invention, it can be provided that the coolant inlet opening of the compressed air generating device is hydraulically connected to a first external cooling device, that a first cooling switching valve is arranged in a first coolant line running from the coolant inlet opening to the coolant inlet of the aftercooler, that the first cooling switching valve is designed as a 2 / 2-way solenoid switching valve which is connected to the control and regulating device for control purposes, and that the first coolant line can be shut off or opened by means of the first cooling switching valve depending on its switching position.

[0019] This makes it possible, for example, to not use the first external cooling device if its cooling fluid has a higher temperature than the temperature of at least one of the components of the compressed air generation device. Such a situation can arise, for example, if a water-air cooler assigned to an internal combustion engine is used as the first external cooling device, and its cooling water has a higher temperature than the temperature of the compressed air in the aftercooler. For this purpose, the temperature of the cooling fluid of the first external cooling device and the temperature of the compressed air at the inlet of the aftercooler are continuously measured during operation, and the measured values ​​are communicated to the control and regulating unit.If the temperature is too high, the control unit switches the first cooling switching valve to a position in which the fluid connection between the first external cooling device and the coolant inlet or the inlet of the aftercooler is closed. This prevents excessively hot cooling water from heating the compressed air instead of cooling it.

[0020] In order to further improve the cooling capacity of the compressed air generating device, it can additionally be provided that the output of the first air compressor can be connected to an input of a second external cooling device via a second cooling switching valve designed as a 3 / 2-way solenoid switching valve, that the second cooling switching valve is connected to the control and regulating device for control purposes, and that the output of the second external cooling device is connected to the input of the second air compressor (18).

[0021] This allows, with a corresponding switching position of the second cooling switching valve, the already warm compressed air generated by the first air compressor to be directed to the aforementioned second external cooling device and cooled there, bypassing the intercooler. This second external cooling device can be designed, for example, as an air-to-air cooler. Such an operating situation can arise if the cooling fluid coming from the first external cooling device and flowing into the compressed air generation device is warmer than the compressed air at the aftercooler, but is still cold enough to cool the other components of the compressed air generation device arranged downstream of the two air coolers in the cooling fluid flow.In this operating situation, the compressed air at the outlet of the first air compressor is cooled in the second external cooling device, and the aftercooler, the intercooler, the electric motor, the inverter and the two air compressors are cooled by the first external cooling device.

[0022] In order to further improve the cooling of this compressed air generating device, it can be provided, alternatively or in addition to the cooling measures mentioned, that the output of the second air compressor can be connected to an input of a third external cooling device via a third cooling switching valve designed as a 3 / 2-way solenoid switching valve, that the third cooling switching valve is connected to the control and regulating device for control purposes, and that the output of the third external cooling device is connected to the input of the air dryer.

[0023] This also allows the compressed air coming from the second air compressor to be cooled in the second external cooling device in operating situations where the cooling fluid of the first external cooling device is too warm to cool the compressed air in the intercooler and the aftercooler. The second external cooling device can also be designed as an air-to-air heat exchanger. The compressed air cooled in the third external cooling device is then returned to the compressed air generation device, where it reaches the air dryer, bypassing the intercooler and the aftercooler.

[0024] In a detailed development, such a compressed air generating device having the features of the invention is equipped with a control and regulating device, with an electric motor, with two air compressors that can be driven by the electric motor and operate one after the other, with an air inlet through which ambient air can be sucked in by means of the first air compressor, with a first air cooler designed and arranged as an intercooler and with a second air cooler designed and arranged as an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, wherein the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and wherein the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, with an air dryer, the inlet of which is pneumatically connected to the outlet of the aftercooler,and with a coolant inlet opening, via which a liquid coolant can be supplied to the intercooler and the aftercooler and other components of the compressed air generating device, as well as with a coolant outlet opening, via which heated coolant can be discharged.

[0025] According to the development of the invention, this compressed air generation device is characterized in that the aftercooler, which is arranged as the last air cooler upstream of the air dryer in the flow direction of the compressed air, is the first through which the coolant can flow in the direction of flow of the coolant, that the coolant inlet opening can be connected to a coolant outlet of a first external cooling device, that an outlet of the first air compressor can be pneumatically connected to an inlet of the intermediate cooler via a first compressed air line DL1, that a ninth compressed air line DL1.1 is connected to this first compressed air line DL1, which ninth compressed air line DL1.1 is pneumatically connected to an inlet of a second external cooling device, that an outlet of the intermediate cooler is pneumatically connected to an inlet of the second air compressor via a second compressed air line DL2, that a tenth compressed air line DL2 is connected to this second compressed air line DL2.1, which is pneumatically connected to an outlet of the second external cooling device, that an inlet of the aftercooler is pneumatically connectable to an outlet of the second air compressor via a third compressed air line DL3, that the third compressed air line DL3 is connectable to an eleventh compressed air line DL3.1, that the eleventh compressed air line DL3.1 is pneumatically connected to the inlet of a third external cooling device, that the outlet of the third external cooling device is connected to a fourth compressed air line DL4 via a twelfth compressed air line DL4.1, and that this fourth compressed air line DL4 connects an outlet of the aftercooler to an inlet of the air dryer.Since it is important to know the temperature of the cooling fluid of the first external cooling device at the inlet of the compressed air generation device or at least at the inlet of the aftercooler in order to activate or deactivate the respective external cooling devices, the arrangement of at least one temperature sensor in this regard is useful.

[0026] Therefore, a compressed air generation device having the features of the invention is, according to a related development, equipped with a control and regulating device, with an electric motor, with two air compressors that can be driven by the electric motor and operate one after the other, with an air inlet through which ambient air can be sucked in by means of the first air compressor, with a first air cooler designed and arranged as an intercooler and with a second air cooler designed and arranged as an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, wherein the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and wherein the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, with an air dryer, the inlet of which is pneumatically connected to the outlet of the aftercooler,and with a coolant inlet opening, via which a liquid coolant can be supplied to the intercooler and the aftercooler and other components of the compressed air generating device, as well as with a coolant outlet opening, via which heated coolant can be discharged.

[0027] This advanced compressed air generation device provides at least one temperature sensor for measuring the coolant temperature, located upstream of the coolant inlet and / or downstream of the coolant outlet of the air cooler that is positioned as the last air cooler upstream of the air dryer in the direction of compressed air flow. This at least one temperature sensor is connected to the control and regulating unit via a data or sensor line. The data or sensor line can be a CAN bus line.

[0028] By installing such a temperature sensor, the control unit can calculate how much the compressed air coming from the air compressor cools in the air cooler, thus separating water from the compressed air before it reaches the air dryer. Using this information, an optimally low volume of dry compressed air can be passed through the air dryer during a regeneration process to dry the desiccant. This minimizes the consumption of dry compressed air and reduces the number and / or duration of regeneration processes on the air dryer to a minimum.

[0029] The design features proposed by the invention can be applied to compressed air generation devices of various configurations. Such a compressed air generation device can have only one or more compressor stages, which can be driven, for example, by a single electric motor or by separate electric motors. The design of the compression stages and the number of air coolers are also not specified with regard to the use of the invention.

[0030] According to another embodiment of the invention, a special feature of the control and regulating device is important. The compressed air generating device is equipped with a control and regulating device, an electric motor, two air compressors driven by the electric motor and operating sequentially, an air inlet through which ambient air can be drawn in by means of the first air compressor, a first air cooler designed and arranged as an intercooler, and a second air cooler designed and arranged as an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, and an air dryer, the inlet of which is pneumatically connected to the outlet of the aftercooler.and with a coolant inlet opening, via which a liquid coolant can be supplied to the intercooler and the aftercooler and other components of the compressed air generating device, as well as with a coolant outlet opening, via which heated coolant can be discharged.

[0031] According to the invention, it is provided that the aftercooler, which is arranged as the last air cooler upstream of the air dryer in the direction of flow of the compressed air, is the first through which the coolant can flow in the direction of flow of the coolant, that at least one temperature sensor is present which is connected to the control and regulating device via a data or sensor line, that the temperature sensor for measuring the coolant temperature is arranged upstream of the coolant inlet or downstream of the coolant outlet of the aftercooler, and that the control and regulating device is designed in such a way that, in addition to the operation of the electric motor, a drying operation and a regeneration operation of the air dryer as well as the operation of a multi-circuit protection valve can be controlled and regulated.

[0032] Because the control and regulating device according to the invention is designed and arranged in such a way that the operation of the electric motor, a drying operation and a regeneration operation of the air dryer, as well as the operation of a multi-circuit protection valve can be controlled and regulated, a separate control and regulating device for controlling and regulating the electric motor or a separate control and regulating device for at least indirectly controlling and regulating a multi-circuit protection valve is not necessary. This saves manufacturing costs and installation space.

[0033] With regard to a more specific arrangement of the at least one temperature sensor, it can be arranged upstream of the coolant inlet opening of the compressed air generation device to measure the coolant temperature. In this case, a temperature sensor that is already arranged on a first external cooling device of a motor vehicle can be used particularly cost-effectively to determine the coolant temperature at the outlet of this external cooling device and to communicate this temperature to the control and regulating unit of the motor vehicle.

[0034] However, if the line length for transporting the coolant from this external cooling device to the compressed air generation device is comparatively long, such an arrangement can be disadvantageous, as the coolant can cool or heat up uncontrollably on its way to the coolant inlet of the compressed air generation device. For this reason, the temperature sensor for measuring the coolant temperature can be arranged directly upstream of the coolant inlet of the aftercooler, which is the last air cooler upstream of the air dryer in the direction of compressed air flow. This provides particularly meaningful measurement values.

[0035] However, it can also be provided that the temperature sensor for measuring the coolant temperature is located as the next component downstream of the coolant outlet of the aftercooler, which is the last air cooler upstream of the air dryer in the direction of compressed air flow. This location for the temperature sensor can be directly at the coolant outlet of the aftercooler, or if the installation space there does not permit this, at the next possible location downstream of the coolant outlet of the aftercooler.

[0036] It can also be provided that a temperature sensor is arranged at both the coolant inlet and the coolant outlet of the aftercooler, which are signal-linked to the control and regulating unit. Using the temperature values ​​measured by these two temperature sensors, a temperature difference can be determined in the control and regulating unit, which is a measure of the cooling of the compressed air in the aftercooler. From this, it is at least possible to estimate how much water has condensed from the compressed air as it flowed through the aftercooler. If necessary, an additional temperature sensor is required for this purpose, with which the temperature of the compressed air at the compressed air inlet of the aftercooler can be measured.

[0037] According to another development of the subject matter of the invention, it can be provided that the at least one electric motor, an inverter influencing the operation of the electric motor, the two air compressors, the intercooler, the aftercooler, the air dryer, the multi-circuit protection valve, which pneumatically connects the outlet of the air dryer to at least one external compressed air reservoir and external compressed air consumers, as well as a silencer are arranged in cooperation but separately with respect to one another.

[0038] Alternatively, it can be provided that the at least one electric motor, an inverter influencing the operation of the electric motor, the two air compressors, the intercooler, the aftercooler, the air dryer, the multi-circuit protection valve, which pneumatically connects the outlet of the air dryer to at least one external compressed air reservoir and external compressed air consumers, as well as a silencer are arranged in or on a common housing.

[0039] In both described design variants, the aforementioned device components are suitably connected to one another via the aforementioned electrical, pneumatic, and hydraulic connecting lines, which may be arranged in the housing. This makes the compressed air generation device extremely compact, easy to assemble during manufacture, and easily attachable to a motor vehicle, for example, a commercial vehicle.

[0040] In this context, it can further be provided that the control and regulating device is arranged separately or in or on the housing, that the control and regulating device is connected via a first control line to the inverter for controlling and regulating the electric motor, that the control and regulating device is connected via a second control line to a regeneration switching valve designed as a first 3 / 2-way solenoid switching valve, which serves to open or close a regeneration line that pneumatically at least indirectly connects the compressed air reservoir and the air dryer, and that the control and regulating device is connected via a sensor line to the multi-circuit protection valve.

[0041] By additionally integrating the control and regulation unit, the first 3 / 2-way solenoid valve or regeneration valve, as well as the associated control lines and regeneration line, into the housing of the compressed air generation device, the device contains additional components associated with the compressed air generation device, making the overall system even easier to handle and connect to the motor vehicle. Therefore, in the event of a malfunction in one of its components, such a compressed air generation device can be easily removed from a commercial vehicle as a whole and taken to a repair shop, while a new compressed air generation device can be quickly and easily installed on the vehicle. Since a compressed air generation device is a vital operational device, especially in commercial vehicles, the procedure described avoids lengthy repairs and allows the commercial vehicle to be quickly put back into operation.

[0042] In order to further improve the repairability of the compressed air generating device and to enable quick repairs, according to another development of the compressed air generating device, it can be provided that it is constructed from several modules which, together with the associated pneumatic, hydraulic and electrical lines, are arranged in or on a common housing.

[0043] Accordingly, it can be provided that a compressor module, a compressed air cooling module, a dryer module and a silencer module together with associated pneumatic, hydraulic and electrical lines are arranged in or on the housing of the compressed air generation device, wherein the compressor module has the electric motor, the inverter, the two air compressors and the control and regulating device, wherein the compressed air cooling module has the intercooler and the aftercooler, wherein the dryer module has the air dryer and the multi-circuit protection valve, wherein the silencer module has the silencer with a sound-damping material, and wherein the silencer module has at least one regeneration air outlet opening for discharging regeneration compressed air into the environment.

[0044] The sound-damping material is designed to absorb water droplets separated by the air dryer and also direct spray water entering the silencer to a water outlet on the silencer module. In certain applications, the integration of a standalone silencer module may be unnecessary.

[0045] Another variant of the compressed air generating device having the features of the invention is equipped with at least one electric motor, with which at least one air compressor can be driven, and which has an air inlet through which ambient air can be drawn in by means of the air compressor. This compressed air generating device has at least one air cooler, in which the air compressed by the air compressor can be cooled. An air dryer is also provided, the inlet of which is pneumatically connected to the outlet of the at least one air cooler. Furthermore, a coolant inlet opening is formed, via which a liquid coolant can be supplied to the air cooler. Furthermore, a coolant outlet opening is provided, via which heated coolant can be discharged.

[0046] This compressed air generating device is characterized in that the silencer has at least one regeneration air outlet opening for discharging regeneration exhaust air guided through it into the environment, that this at least one regeneration air outlet opening serves as an air inlet for sucking in ambient air towards the at least one air compressor when no regeneration of the drying agent of the air dryer takes place, and that the ambient air sucked in through the silencer can be guided downstream behind the silencer through an intake air line to the at least one air compressor.

[0047] A further development of the compressed air generation device derived therefrom has the following: at least one electric motor, two air compressors which can be driven by the electric motor and act one after the other, an air inlet via which ambient air can be sucked in by means of the first air compressor, as well as an intercooler and an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, wherein the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and wherein the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, further comprising an air dryer whose inlet is connected to the outlet of the aftercooler, as well as a coolant inlet opening via which a liquid coolant can be supplied to the intercooler and the aftercooler, and a coolant outlet opening via which heated coolant can be discharged.

[0048] This further developed compressed air generating device is also characterized in that the silencer has at least one regeneration air outlet opening for discharging regeneration exhaust air guided through it into the environment, that the at least one regeneration air outlet opening serves as an air inlet for sucking in ambient air towards the first air compressor when no regeneration of the drying agent of the air dryer takes place, and that the ambient air sucked in through the silencer can be guided downstream behind the silencer through an intake air line to the first air compressor.

[0049] To prevent unwanted contamination or excessive splashing of the silencer via the combined inlet and outlet for the ambient air to be drawn in, as well as the removal of moisture-containing regeneration compressed air, another refinement of the compressed air generation device provides for a separator for separating water and particles to be arranged in front of or in the silencer. This separator is designed and arranged such that it can be used to free the ambient air drawn in through the at least one regeneration air outlet opening, which also serves as an air inlet, of entrained water droplets and particles. Such a separator can be designed, for example, as a cyclone separator, in which the drawn-in ambient air is directed in a circular or spiral motion.

[0050] Another compressed air generating device incorporating the features of the invention also has at least one electric motor, with which at least one air compressor can be driven. Furthermore, an air inlet is provided, through which ambient air can be drawn in by means of the air compressor. Furthermore, at least one air cooler is provided, in which the air compressed by the air compressor can be cooled. Furthermore, an air dryer is arranged, the inlet of which is pneumatically connected to the outlet of the at least one air cooler. Furthermore, a coolant inlet opening is formed on the compressed air generating device, via which a liquid coolant from a first external cooling device can be supplied to the air cooler. Heated coolant can be returned to the first external cooling device via a coolant outlet opening, which is also provided.In addition, a multi-circuit protection valve is provided, which pneumatically connects the air dryer outlet to at least one external compressed air reservoir and external compressed air consumers. A control and regulation unit is also provided, which is connected to the multi-circuit protection valve and the sensors located there via at least one sensor line.

[0051] In order to make this compressed air generation device independent of a specific, possibly vehicle-specific multi-circuit protection valve, according to a further development in question here, it is provided that the multi-circuit protection valve can be separated from the other components of the compressed air generation device and can be operated remotely from these components, that the control and regulating device and the multi-circuit protection valve have electrical connecting means which are detachably connected to one another via at least one flexible electrical line, and that the multi-circuit protection valve has pneumatic connecting means which are detachably connected at least indirectly to the outlet of the air dryer via at least one flexible pneumatic line.

[0052] The invention also relates to a more detailed further development of the variant of the compressed air generation device just described, with at least one electric motor, with two air compressors that can be driven by the electric motor and operate one after the other, with an air inlet through which ambient air can be sucked in by means of the first air compressor, with an intercooler and an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, wherein the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and wherein the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, with an air dryer, the inlet of which is connected to the outlet of the aftercooler, with a coolant inlet opening through which a liquid coolant can be supplied to the intercooler and the aftercooler, with a coolant outlet opening,via which heated coolant can be discharged, with a multi-circuit protection valve which pneumatically connects the outlet of the air dryer to at least one external compressed air reservoir and external compressed air consumers, as well as with a control and regulating device which is connected via at least one sensor line to the multi-circuit protection valve and sensors arranged there.

[0053] The invention also provides in this variant of the compressed air generation device that the multi-circuit protection valve can be separated from the other components of the compressed air generation device and can be operated remotely from these components, that the control and regulating device and the multi-circuit protection valve have electrical connecting means which are detachably connected to one another via at least one flexible electrical sensor line, and that the multi-circuit protection valve has pneumatic connecting means which are detachably connected at least indirectly to the outlet of the air dryer via at least one flexible pneumatic line.

[0054] In a further embodiment of the two compressed air generation devices just described, it is provided that a dryer module having the air dryer has at least one electrical plug socket and at least one pneumatic plug socket, that the electrical plug socket of the dryer module is connected to an electrical plug socket on the control and regulating device via the sensor line, that an electrical plug of an electrical connecting line can be releasably inserted into the electrical plug socket of the dryer module, that this electrical connecting line has a second plug which can be releasably inserted into an electrical plug socket of the multi-circuit protection valve, that the pneumatic plug socket of the dryer module is pneumatically connected to the fifth compressed air line through which dried compressed air coming from the air dryer can be conducted,that a plug of a pneumatic connecting line can be releasably inserted into this pneumatic plug socket of the dryer module, and that the pneumatic connecting line has a second plug which can be releasably inserted into a pneumatic plug socket of the multi-circuit protection valve.

[0055] In order to make a compressed air generating device having the features of the invention particularly compact, i.e. space-saving, it has at least one electric motor with which at least one air compressor can be driven. This at least one air compressor can draw in ambient air via an air inlet. Furthermore, at least one air cooler is provided, in which the air compressed by the at least one air compressor can be cooled. In addition, an air dryer is arranged, with which compressed air cooled by the air cooler can be dried. In addition, this compressed air generating device has a coolant inlet opening, via which a liquid coolant can be supplied to the air cooler. Heated coolant can be discharged via a likewise formed coolant outlet opening.

[0056] This compressed air generation device has now been further developed in such a way that the control and regulating unit is an integral component of the inverter. This allows for a very compact design of the aforementioned compressor module, in which the at least one electric motor, the inverter, the two air compressors, and the intercooler associated with these air compressors are located. The control and regulating unit is therefore structurally incorporated into a housing of the inverter or forms a structural unit with it, so that the control line from the control and regulating unit to the inverter's electronics is optimally short. Of course, the described design can also be implemented in a reversible manner, namely with the inverter being an integral component of the control and regulating unit.

[0057] In a further embodiment of this integration of the control and regulating device, the compressed air generation device can also be designed as follows: comprising at least one electric motor, two air compressors that can be driven by the electric motor and operate one after the other, an air inlet through which ambient air can be sucked in by means of the first air compressor, an intercooler and an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, wherein the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and wherein the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, and further comprising an air dryer, the inlet of which is connected to the outlet of the aftercooler, a coolant inlet opening through which a liquid coolant can be supplied to the intercooler and the aftercooler, a coolant outlet opening,through which heated coolant can be discharged, a multi-circuit protection valve that pneumatically connects the air dryer outlet to at least one external compressed air reservoir and external compressed air consumers, and a control and regulating device that is connected to the multi-circuit protection valve and sensors arranged there via at least one sensor line. In this development of the compressed air generation device, it is provided that the control and regulating device, with the aforementioned advantages, is also an integral component of the inverter.

[0058] The control and regulation device can also be integrated into the multi-circuit protection valve, or vice versa. According to this further development, we are dealing here with a compressed air generation device comprising at least one electric motor, two air compressors driven by the electric motor and operating sequentially, an air inlet through which ambient air can be drawn in by means of the first air compressor, an intercooler, and an aftercooler, wherein the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler, as well as an air dryer, the inlet of which is connected to the outlet of the aftercooler, and a coolant inlet opening through which a liquid coolant can be supplied to the intercooler and the aftercooler.a coolant outlet opening through which heated coolant can be discharged, a multi-circuit protection valve that pneumatically connects the air dryer outlet to at least one external compressed air reservoir and external compressed air consumers, and a control and regulating device that is connected to the multi-circuit protection valve and sensors arranged there via at least one sensor line. According to this development, the control and regulating device is an integral component of the multi-circuit protection valve.

[0059] Alternatively, in the compressed air generation device just described, the features of which will not be repeated here, the control and regulating unit can be an integral component of a, preferably central, vehicle control unit. This saves additional costs and installation space for the provision of the device's own control and regulating unit; however, sensor and control lines for operating the compressed air generation device must be provided from this control and regulating unit to the vehicle's central vehicle control unit.

[0060] The compressed air generation device with the features of the invention is designed in such a way that the air dryer can be optimally operated both for drying the compressed air and for regeneration, i.e., for dehumidifying its drying agent. For this purpose, as will be explained in detail with reference to an exemplary embodiment, it is preferably provided that the outlet of the air dryer is connected to a fifth compressed air line via a first check valve opening toward the air dryer; that this fifth compressed air line leads via the aforementioned multi-circuit protection valve to the at least one compressed air reservoir and to compressed air consumers; that a regeneration compressed air inlet of the air dryer is connected to the outlet of a first regeneration switching valve designed as a 3 / 2-way solenoid valve via a second check valve opening toward the regeneration compressed air inlet, an orifice plate, and a first line branch.that the inlet of this first 3 / 2-way solenoid valve is connected to the fifth compressed air line via a regeneration line, that when the first 3 / 2-way solenoid valve is actuated, dry compressed air can be supplied to the air dryer as regeneration compressed air via this 3 / 2-way solenoid valve, the first line branch, the orifice plate and the first check valve, and that, likewise when the first 3 / 2-way solenoid valve is actuated, regeneration compressed air can be supplied via a second line branch to the pneumatic control inlet of a pneumatically actuated 2 / 2-way switching valve, which is assigned to a regeneration air outlet of the air dryer.

[0061] A regeneration process in the air dryer is therefore initiated by the control and regulation unit and pneumatically controlled primarily by the first 3 / 2-way solenoid valve or regeneration switching valve. This first 3 / 2-way solenoid valve directs dry regeneration compressed air to the air dryer, while simultaneously supplying a pneumatic control pressure to a control pressure inlet of the pneumatic 2 / 2-way switching valve to open a regeneration air outlet of the air dryer. This control pressure is generated by a small portion of the regeneration compressed air, which, coming from the compressed air reservoir, is largely directed into the air dryer to dry the desiccant there.

[0062] Another development provides that the pressure-controlled 2 / 2-way switching valve is assigned to a collection area of ​​the air dryer, wherein the pneumatic control input of this 2 / 2-way switching valve is connected to the output of the first 3 / 2-way solenoid valve via a second line branch. This 2 / 2-way switching valve is designed such that it is closed when not actuated. The pressure-controlled 2 / 2-way switching valve can also be switched from its closed position to its open position by means of regeneration compressed air supplied to the air dryer and via the second line branch. When the pressure-controlled 2 / 2-way switching valve is open, dry regeneration compressed air can be passed through the drying agent of the air dryer in a regeneration compressed air stream.After flowing through the desiccant, the regeneration compressed air can be directed into the collection area of ​​the air dryer and can entrain any condensed water that has accumulated there and remove it from the air dryer via at least one regeneration air outlet.

[0063] In addition, the compressed air generation device preferably has an additional temperature sensor for measuring the ambient temperature. This additional temperature sensor is also connected to the control and regulation unit via a data or sensor line. If a data line is used, this can be a CAN bus line.

[0064] The invention also relates to a method for operating a compressed air generating device with the described features. According to the method, compressed air is cooled in at least one air cooler by means of the at least one air compressor. The cooled compressed air is subsequently fed to an air dryer and dried there, before being directed to compressed air consumers and / or at least one compressed air reservoir. During a regeneration operation of the compressed air generating device, dry compressed air is passed through the drying agent in the amount of a required regeneration compressed air volume to regenerate a drying agent arranged in the air dryer and is then discharged into the environment.

[0065] It is provided that the regeneration compressed air volume required for the regeneration of the drying agent is calculated at least as a function of the temperature which the coolant has before and / or after flowing through the air cooler which is arranged as the last air cooler in front of the air dryer, and that the regeneration compressed air volume of dry compressed air determined in this way is then passed through the air dryer.

[0066] Since the amount of water that the compressed air carries as air humidity after passing the last air cooler to the air dryer depends on the compressed air temperature there, it may initially seem disadvantageous not to determine the regeneration compressed air volume required for regeneration operation of the compressed air generation device on the basis of a direct measurement of the temperature of the compressed air flow upstream of the air dryer.

[0067] The method presented here, however, has the advantage that no additional temperature sensor is required to obtain information about the temperature of the compressed air before it reaches the air dryer and the water content in the form of humidity that this compressed air carries. As already explained above, in every motor vehicle with a liquid cooling system today, the coolant temperature after it leaves the radiator is measured using a temperature sensor, and the measured values ​​are made available in the vehicle for a variety of purposes, for example via a CAN data bus. By knowing the temperature of the coolant directly after it leaves the vehicle radiator or immediately before the aforementioned air cooler, the temperature of the compressed air after it leaves this air cooler can be indirectly determined without the need for a separate temperature sensor.

[0068] The operation of the compressed air generation device, and in particular the supply of coolant, is then regulated to maximize the cooling effect of the last air cooler before the air dryer. This maximizes the cooling effect of the compressed air before the air dryer, resulting in comparatively low levels of moisture that would burden the air dryer. As a result, the air dryer's desiccant needs to be regenerated less frequently or with a smaller regeneration compressed air volume.

[0069] In a further embodiment of the method, it is provided that the coolant temperature is measured upstream of the coolant inlet opening of the compressed air generating device by means of a first temperature sensor, and that the regeneration compressed air volume required for drying the drying agent in the air dryer is passed through the air dryer in a controlled and / or regulated manner depending on the measured coolant temperature during a later regeneration process.Alternatively, it can be provided that the coolant temperature is measured by means of a second temperature sensor in this list immediately upstream of the coolant inlet of the air cooler which is arranged as the last air cooler upstream of the air dryer in the direction of flow of the compressed air, and that the regeneration compressed air volume required for drying the drying agent in the air dryer is passed through the air dryer in a controlled and / or regulated manner depending on the measured coolant temperature during a later regeneration process.

[0070] Furthermore, it can be provided that the coolant temperature is measured by means of a third temperature sensor behind the coolant outlet of the air cooler which is arranged as the last air cooler in front of the air dryer in the direction of flow of the compressed air, and that the regeneration compressed air volume required for drying the drying agent in the air dryer is passed through the air dryer in a controlled and / or regulated manner depending on the measured coolant temperature during a later regeneration process.

[0071] According to a further specialization of the method, the following method steps can be provided: a) Suction of ambient air by means of the first air compressor, b) Pre-compression of the sucked in ambient air in the first air compressor to a first air pressure value, c) Cooling of an intercooler with a liquid coolant, d) Cooling of the pre-compressed compressed air in the intercooler, e) Further compression of the compressed air to a second, higher pressure value by means of a second air compressor, f) Cooling of an aftercooler with the liquid coolant, wherein the aftercooler is reached hydraulically by the coolant as the first air cooler, seen in the flow direction of the coolant, g) Cooling of the compressed air further compressed in the second air compressor in the aftercooler, h) Drying of the cooled compressed air in an air dryer, i) Forwarding of the cooled and dried compressed air to compressed air consumers and / or to at least one compressed air reservoir.These process steps make it clear that the compressed air that has left the second air compressor is cooled as it flows through the aftercooler to the extent that the freshly supplied liquid coolant allows. For this purpose, the liquid coolant is not first directed to a cooling device of the electric motor or to the intercooler in order to cool them during operation, as is the case with the compressed air generation device according to DE 10 2039 139 424.6. Instead, in the compressed air generation device presented here, the coolant is first directed to the aftercooler in order to cool this and, as a result, also the compressed air as much as possible. This makes it possible, according to the process, to cool the generated compressed air so much before it reaches the air dryer that as much moisture as possible is separated and removed from the compressed air.

[0072] In order to also cool other components of the compressed air generation device with the liquid coolant, the following further method steps are provided in addition to the method just mentioned: j) passing the liquid coolant from the aftercooler to the intercooler, k) passing the liquid coolant from the intercooler to a cooling device of the electric motor, l) passing the liquid coolant from the cooling device of the electric motor to a cooling device of the second air compressor, m) passing the liquid coolant from the cooling device of the second air compressor to a cooling device of the inverter, n) passing the liquid coolant from the cooling device of the inverter to a cooling device of the first air compressor, o) passing the liquid coolant from the cooling device of the first air compressor to an external cooling device.

[0073] In addition to guiding the coolant, particularly first to the aftercooler, and guiding the compressed air in the compressed air generation device, the regeneration of the drying agent in the air dryer is particularly important. During this regeneration, temporarily stored dry compressed air flows through the drying agent, which has removed moisture from the supplied compressed air during previous drying processes and has now greatly reduced its drying capacity, in the opposite direction. The compressed air absorbs water from the drying agent and, laden with it, flows out of the air dryer into the environment. The frequency with which such regeneration processes must be carried out and the volume of compressed air required for these regeneration processes influence the demand for compressed air generated by the compressed air generation device during vehicle operation.Since water is already separated from the compressed air in the aftercooler during the cooling of the compressed air described above, this water reaches the inlet area of ​​the air dryer as a water film or as small droplets with the compressed air fed to the air dryer, from where it is discharged into the environment before reaching the drying agent.

[0074] However, it may just as well be provided that the time interval between two regeneration processes for drying the desiccant of the air dryer is controlled and / or regulated as a function of the temperature of the coolant which the coolant has at the outlet of the external cooling device or at the inlet of the aftercooler.

[0075] Since the temperature of the coolant determines how much water has already condensed from the compressed air supplied to it at the aftercooler, a comparatively low coolant temperature results in a comparatively large amount of water being separated from the compressed air at the aftercooler, which is then discharged from there. As a result, the air dryer's desiccant is subjected to less stress, so the regeneration compressed air volume can be lower or, for example, the time interval between two regeneration processes can be longer than with a comparatively high coolant temperature.

[0076] The ambient temperature of a vehicle must also be taken into account when performing regeneration processes of the type described, because the compressed air stored in a compressed air reservoir gradually takes on the ambient temperature via the walls of the compressed air reservoir. Since the compressed air stored in this compressed air reservoir is also used to regenerate the desiccant in the air dryer, and the compressed air temperature also determines the water storage capacity of the regeneration compressed air, knowledge of the ambient temperature is important for determining the required regeneration compressed air volume.Therefore, in the method in which previously dried and temporarily stored compressed air is passed through the air dryer as regeneration compressed air in the opposite direction to regenerate a desiccant arranged in the air dryer, it can be provided that the time interval between two regeneration processes for drying the desiccant of the air dryer is controlled and / or regulated depending on the average ambient temperature during a subsequent regeneration process. The average ambient temperature can be determined over a predetermined period of time.

[0077] This method can also provide for the regeneration compressed air volume required for drying the desiccant to be controlled and / or regulated depending on the average ambient temperature during a subsequent regeneration process.

[0078] For example, if both the ambient temperature and the coolant temperature change rapidly due to the current driving situation and / or rapidly changing ambient conditions, it can be provided that the regeneration compressed air volume required for drying the desiccant or the duration and / or frequency of the regeneration processes is also controlled and regulated depending on the difference between the ambient temperature and the coolant temperature.

[0079] In the case of uncontrolled control of the regeneration of the drying agent of the air dryer, according to another development of the method for operating the compressed air generating device presented, it is provided that a maximum high temperature value of the coolant to be expected during operation of the compressed air generating device is determined, that this value of the coolant temperature serves as the basis for determining a maximum regeneration compressed air volume, and that a corresponding regeneration process for the drying agent is carried out with this maximum regeneration compressed air volume.In order to achieve maximum cooling of the compressed air before it is dried in the drying agent of the air dryer, it can be provided in a further development of the method presented above that the cooling liquid coming from the coolant outlet of the intercooler is not conveyed directly, but via a dryer module cooler to the coolant inlet of the electric motor, and that the dryer module cooler cools at least components of the air dryer.

[0080] Alternatively or in addition to the method variant just mentioned, it can be provided that the temperature of the coolant is measured at the outlet of the first external cooling device or at the inlet of the aftercooler. When the determined coolant temperature has reached or exceeded a previously defined high first limit value, the compressed air from the outlet of the first air compressor is no longer transported via the intercooler but via the aforementioned second external cooling device to the inlet of the second air compressor. The first limit value of the temperature can be, for example, 80° Celsius.

[0081] This process variant is used primarily when the temperature of the cooling liquid coming from the first external cooling device is higher than the temperature of the compressed air at the pneumatic inlet of the intercooler and / or at the pneumatic inlet of the aftercooler, because in this case the compressed air cannot be cooled using these air coolers. In this case the compressed air is directed from the outlet of the first air compressor to the inlet of the second external cooling device, where the compressed air is cooled. After flowing through the second external cooling device, the cooled compressed air is directed to the inlet of the second air compressor, where it is brought to an even higher air pressure. In the further course of the process the compressed air can then be directed via the aftercooler, which in this situation is switched to passive mode with regard to its cooling capacity, and from there to the air dryer in the usual way.

[0082] In addition, a third external cooling device can be used if the temperature of the liquid coolant of the first external cooling device is too high to cool the compressed air in the intercooler and the aftercooler, and the cooling capacity of the second external cooling device is not sufficient to achieve such a low temperature of the compressed air that a comparatively large proportion of the humidity in the compressed air condenses into transportable water droplets even before the air dryer.In order to achieve this in the described operating situation of the compressed air generation device, it is provided that the temperature of the cooling liquid is measured at the outlet of the first external cooling device or at the inlet of the aftercooler, and that when the temperature of the coolant has reached or exceeded a previously defined second limit value which is greater than the first limit value, the transport of compressed air coming from the outlet of the first air compressor does not take place via the intercooler but via the second external cooling device to the inlet of the second air compressor, and that then additionally the transport of compressed air coming from the outlet of the second air compressor is not directed via the aftercooler but via the third external cooling device to the outlet of the aftercooler or to the inlet of the air dryer.

[0083] With the last two procedures described, it must be ensured that the other components of the compressed air generation device to be cooled, i.e., the electric motor, the inverter, and the two air compressors, are cooled in another way by the liquid coolant of the first external cooling device, provided the temperature of the coolant is suitable. This means that even if no compressed air is passed through the intercooler and / or the aftercooler, the liquid coolant of the first external cooling device is passed through the cooling devices of the electric motor, the inverter, and the two air compressors.

[0084] This can be achieved by means of additional coolant lines and at least one additional, properly arranged switching valve.

[0085] For a better understanding of the invention, a drawing with several embodiments is attached to the description. In this drawing,

[0086] Fig. 1 is a schematic representation of an electrically driven compressed air generating device that can be cooled by an external cooling device, comprising two air compressors, an intercooler, an aftercooler, an air dryer, a multi-circuit protection valve, a dryer module cooler and a silencer. Fig. 2 is a compressed air generating device similar to that shown in Fig. 1, to which three external cooling devices can be connected by means of formed connections and internal piping.

[0087] Fig. 3 is a schematic detailed view of the internal piping and connections of the compressed air generating device according to Fig. 2,

[0088] Fig. 4 shows a compressed air generating device similar to that according to Fig. 1, in which ambient air can be sucked in by a first air compressor through the silencer,

[0089] Fig. 5 shows a compressed air generating device similar to that according to Fig. 4, but with a different arrangement of a coolant temperature sensor, and with a water and particle filter arranged in the silencer, through which sucked ambient air can be guided to the first air compressor, Fig. 6 shows a compressed air generating device similar to that according to Figures 1 to 5, in which a multi-circuit protection valve is arranged and operable outside a dryer module,

[0090] Fig. 7 shows a compressed air generating device similar to that according to Fig. 6, in which a multi-circuit protection valve is arranged outside the compressed air generating device and is connected to an electrical control and regulating device or to the dryer module via flexible electrical and flexible pneumatic lines, and Fig. 8 shows a compressed air generating device similar to that according to Fig. 5, in which, however, the ambient air for the first air compressor can be sucked in through an air inlet in the compressor module.

[0091] In this drawing, pneumatic lines carrying air or compressed air are shown with solid lines. Hydraulic lines carrying a liquid coolant are shown with dashed lines, and electrical lines are shown with dotted lines.

[0092] A basic structure of a compressed air generating device having the features of the invention is explained below with reference to Fig. 8.

[0093] The compressed air generating device 2.7 shown in Fig. 8 has, in this exemplary embodiment, a closed, but also openable, housing 6 in which components of the compressed air generating device 2.7 are combined into modules arranged one behind the other. Thus, the compressor 4, comprising an electric motor 24 with two drive shafts 30, 32, an inverter 26, a first air compressor 16, a second air compressor 18, and a control and regulating device 28, is arranged in a compressor module 90.

[0094] Furthermore, a compressed air cooling module 92 is arranged in the housing 6, which has an intercooler 20 and an aftercooler 22. These two air coolers 20, 22 serve to cool the compressed air generated by the compressor 4. For this purpose, the two air coolers 20, 22 use a liquid coolant supplied by a first external cooling device 82. In the example chosen here, this first external cooling device 82 is a cooling device of a commercial vehicle with a suitable heat exchanger (not shown here). The aftercooler 22 is arranged such that it is the first component to be supplied with cold liquid coolant by the external cooling device 82. Furthermore, this aftercooler 22 is the last air cooler arranged upstream of an air dryer 40 in the compressed air stream coming from the second air compressor 18.

[0095] To measure the coolant temperature, at least one temperature sensor is arranged, which is connected to the control and regulating unit 28 via a data or sensor line 59. The temperature sensor 73 can be arranged at the coolant outlet of the first external cooling device 82. Alternatively, the temperature sensor 73' can be arranged at the coolant inlet of the aftercooler 22, or the temperature sensor 73" can be arranged at the coolant outlet of the aftercooler 22. The most cost-effective arrangement of such a temperature sensor 73 is probably the arrangement at the coolant outlet of the external cooling device 82.

[0096] If a temperature sensor 73', 73" is arranged at the coolant inlet and at the coolant outlet of the aftercooler 22, the temperature reduction of the coolant as it flows through the aftercooler 22 can be determined by calculating the difference between the measured values ​​supplied by the two temperature sensors 73', 73", and thus the cooling effect on the compressed air to be cooled can be determined. The reduction in the compressed air temperature occurring at the aftercooler 22 due to the described energy transfer to the coolant can be determined, for example, if the temperature of the compressed air at the compressed air inlet of the aftercooler 22 and the second-by-second compressed air volume flow through the aftercooler 22 are also known. Based on the reduction in the compressed air temperature that can be determined in this way, it can be determined which dew point shift of the compressed air has occurred and how much water W is separated from the compressed air at the aftercooler 22 every second.

[0097] Next, a dryer module 94 is located in the housing 6, in which the aforementioned air dryer 40 and a multi-circuit protection valve 50 are arranged. The air dryer 40 contains a desiccant 41, with which humidity can be removed from the compressed air supplied to the air dryer 40. The desiccant 41 can release this moisture back into dry air, namely when dry compressed air is passed through the air dryer 40 in the opposite direction during a regeneration process.

[0098] As will be explained further, the multi-circuit protection valve 50 does not have to be a component of the dryer module 94, but its arrangement in the common housing 6 is advantageous. Using the multi-circuit protection valve 50, it is possible to selectively deliver compressed air delivered by the air dryer 40 via compressed air lines DL6, DL7 to different compressed air consumers 50, 51 and / or via a compressed air line DL8 to at least one compressed air reservoir 45. It should also be mentioned that the sixth compressed air line DL6 and the seventh compressed air line DL7 leading to the compressed air consumers 50, 51 can also be connected to other compressed air reservoirs along the way. Likewise, at least one further compressed air consumer (not shown) can be connected to the illustrated compressed air reservoir 45.A first 3 / 2-way solenoid valve 72 located in the dryer module 94 enables the air dryer 40 to be switched to either an air drying mode or a regeneration mode, in which case the desiccant 41 of the air dryer 40 can be dried. This will be discussed further below. The first 3 / 2-way solenoid valve 72 is also referred to as the regeneration switching valve.

[0099] Finally, the compressed air generation device 2.7 has a silencer module 96, which is designed here as a silencer 43 containing a sound-damping material 44, which is only partially shown in the figures for better visibility of other details. This sound-damping material 44 is capable of dampening sound emissions that arise during a regeneration process when moisture-laden regeneration exhaust air AL is discharged from the air dryer 40. The silencer module 96 has a plurality of regeneration air outlet openings, of which only one regeneration air outlet opening 34 is shown, through which regeneration exhaust air AL can be discharged into the environment.In addition, the silencer module 96 or the silencer 43 has at least one water outlet opening 36 at its lowest point, through which water droplets separated from the compressed air in the air dryer 40 during normal operation and / or spray water penetrated through the regeneration air outlet opening 34 can be removed via a water separation path 80 that forms. The silencer module 96, the silencer 43, or the sound-damping material 44 can be attached to the housing 6 in an easily replaceable manner.

[0100] The components of the four modules 90, 92, 94, 96 described are connected to each other via pneumatic, hydraulic and electrical lines as necessary, which will be discussed separately in the description of the method for operating the compressed air generation device 2.7.

[0101] The functionality and interaction of the components of the compressed air generation device 2.7 are as follows:

[0102] The operation of the compressor 4 is controlled and regulated by the aforementioned control and regulating device 28. The control and regulating device 28 is connected via a low-voltage line 57 to a low-voltage source (not shown in detail), to the aforementioned data or sensor line 59 of an on-board data communication system, such as a CAN bus, and to at least one control line 54. This control line 54 leads to an inverter 26. The inverter 26, which influences the operation of the electric motor 24, is connected via a high-voltage line 58 to an electrical voltage source (not shown separately). To start and operate the electric motor 24 of the compressor 4, it is controlled in the desired manner by means of the control and regulating device 28 and the inverter 26. This causes the two drive shafts 30, 32 of the electric motor 24 to rotate.The first drive shaft 30 is drivingly connected to the first air compressor 16, and the second drive shaft 32 is drivingly connected to the second air compressor 18. The two air compressors 16, 18 are known scroll compressors. The first air compressor 16 is connected to the ambient air L on the inlet side via an air inlet opening 8 in the housing 6. During operation of the first air compressor 16, it draws in ambient air L via an intake line DL and compresses it into compressed air with a first air pressure value.

[0103] The first air compressor 16 is pneumatically connected on the output side via a first compressed air line DL1, the intercooler 20, and then via a second compressed air line DL2 to the inlet of the second air compressor 18. The intercooler 20 cools the pre-compressed compressed air, condensing any water and removing it. In the second air compressor 18, the cooled compressed air is then further compressed to a desired second, higher air pressure value and subsequently fed to the aforementioned aftercooler 22 via a third compressed air line DL3. The compressed air is further cooled in the aftercooler 22. In the process, humidity condenses from the compressed air.

[0104] From the outlet of the aftercooler 22, the cooled and still residually moist compressed air reaches an inlet-side collection area 49 of the air dryer 40 via a fourth compressed air line DL4. The already condensed water also reaches this collection area 49 of the air dryer 40 in the form of entrained small droplets or as a water film. From there, the water W is expelled from the air dryer 40 during a later regeneration process via a regeneration air outlet 42. As a result, the condensed water did not reach the drying agent 41 of the air dryer 40, as is also schematically illustrated in Fig. 8 with small droplets. The compressed air, partially dehydrated in this way and still residually moist, arrives from the short fourth compressed air line DL4 into the drying agent 41 of the air dryer 40, flows through this drying agent 41 in a drying air stream 23, and is dried there.The desiccant 41 is capable of removing humidity from the supplied compressed air and releasing it back into dry air during a later regeneration process.

[0105] The dried compressed air then leaves the air dryer 40 via a spring-loaded first check valve 29 that blocks the air dryer 40, and then enters a fifth compressed air line DL5. This fifth compressed air line DL5 leads to the aforementioned multi-circuit protection valve 50, which is at least indirectly controlled by the control and regulating device 28. For this purpose, the multi-circuit protection valve 50 is connected to the control and regulating device 28 via a sensor line 56. Via the multi-circuit protection valve 50, the dried compressed air can be directed, for example, through the aforementioned sixth compressed air line DL6 and a compressed air outlet opening 10 in the housing 6 to the first compressed air consumer 51 and via the aforementioned seventh compressed air line DL7 to the second compressed air consumer 52. The multi-circuit protection valve 50 can direct dried compressed air to at least one compressed air reservoir 45 via the eighth compressed air line DL8.Other compressed air consumers and / or compressed air reservoirs (not shown) can also be supplied with compressed air as needed via the compressed air reservoir 45. The compressed air stored in the compressed air reservoir 45 can also be supplied to other compressed air consumers via the multi-circuit protection valve 50 if needed, or can be returned to the fifth compressed air line DL5 for regeneration of the desiccant 41 of the air dryer 40.

[0106] When a predetermined air pressure is set at the compressed air consumers 51, 52 and in the at least one compressed air reservoir 45, and the electric motor 24 of the compressor module 90 is switched off, the moisture-saturated desiccant 41 arranged in the air dryer 40 can be regenerated, i.e., freed from the water stored there. For this purpose, the compressed air generating device 2.7 has a regeneration line DL5a. This regeneration line DL5a is indirectly connected via the fifth compressed air line DL5 to at least the eighth compressed air line DL8 leading to the compressed air reservoir 45, as well as to the air dryer 40. The first 3 / 2-way solenoid valve 72 mentioned above is arranged in the regeneration line DL5a. This valve is connected to the control and regulating unit 28 via a control line 55 and can be controlled by it.When this first 3 / 2-way solenoid valve 72 is not actuated, the regeneration line DL5a is closed, as shown in Fig. 8, so that no compressed air can pass from the compressed air reservoir 45 to the air dryer 40 via the multi-circuit protection valve 50. To carry out regeneration operation of the air dryer 40, the first 3 / 2-way solenoid valve 72 is actuated, as a result of which the regeneration line DL5a is opened. As a result, a portion of the dried compressed air passes from the compressed air reservoir 45 through a first line branch DL5b of the regeneration line DL5a to an orifice 75. There, the dried compressed air is expanded, causing it to occupy a larger volume. The compressed air then passes through a second spring-loaded check valve 76, which opens toward the air dryer 40, and then enters the air dryer 40 via a regeneration compressed air inlet 70.The relaxed compressed air then flows through the air dryer 40 and the drying agent 41 arranged there in a regeneration compressed air flow 77, provided that a pressure-controlled 2 / 2-way switching valve 39 acting as a drain valve at the collection area 49 of the air dryer 40 is open.

[0107] To actuate this pressure-controlled 2 / 2-way switching valve 39, another portion of the dried compressed air is routed downstream of the outlet of the first 3 / 2-way solenoid switching valve 72 through a second line branch DL5c to this pressure-controlled 2 / 2-way switching valve 39. The pressure-controlled 2 / 2-way switching valve 39 is designed such that, in its unactuated switching position, it closes a connection from the collection area 49 of the air dryer 40 to the regeneration air outlet 42 of the air dryer 40, and opens it in the actuated switching state. Accordingly, the pressure-controlled 2 / 2-way switching valve 39 is open when the first 3 / 2-way solenoid switching valve 72 has also been switched to its open position.

[0108] According to an alternative embodiment, instead of the first 3 / 2-way solenoid valve 72, two 2 / 2-way solenoid valves controllable by the control and regulating unit 28 are provided. These two 2 / 2-way solenoid valves are not shown in the figures, but their arrangement will be easily understood by a person skilled in the art based on the following description. The first 2 / 2-way solenoid valve is arranged upstream of the orifice 75 in the first line branch DL5b in the flow direction of the regeneration compressed air, and the second 2 / 2-way solenoid valve is arranged upstream of the pressure-controlled 2 / 2-way solenoid valve 39 in the second line branch DL5c. In addition, the fifth compressed air line DL5 is connected in the flow direction of regeneration compressed air upstream of the two 2 / 2-way solenoid valves directly to the first line branch DL5b and directly to the second line branch DL5c.As soon as these two 2 / 2-way solenoid valves are switched to their open position, with the pressure-controlled 2 / 2-way switching valve 39 also opened, dry regeneration compressed air can be passed through the air dryer 40 into the silencer 43 in order to dry the drying agent 41.

[0109] By means of this construction, when the first 2 / 2-way solenoid valve is closed, the second 2 / 2-way solenoid valve is open and the pressure-controlled 2 / 2-way switching valve 39 is therefore open, the collecting area 49 of the air dryer 40 can be advantageously freed of water W accumulated there by means of compressed air supplied via the aftercooler 22.

[0110] But now back to the embodiment shown in Fig. 8: With the pressure-controlled 2 / 2-way switching valve 39 open, the expanded compressed air flows through the desiccant 41 in the aforementioned regeneration compressed air stream 77 toward the silencer 43. In the process, moisture is removed from the desiccant 41. The compressed air thus enriched with moisture, as well as the previously condensed water collected in the collection area 49 of the air dryer 40, then leave the air dryer 40 via its regeneration air outlet 42 and thus enter the silencer 43.

[0111] The moist regeneration exhaust air AL then flows through the sound-damping material 44 arranged in the silencer 43 via an exhaust air path 78 to the at least one regeneration air outlet opening 34 of the silencer 43 of the compressed air generation device 2.7. Water droplets that may have formed in the regeneration compressed air flow or that form in the sound-damping material 44 of the silencer 43 as the regeneration compressed air flow flows through it, as well as the condensed water from the collection area 49 of the air dryer 40, flow in the silencer 43 via the aforementioned water separation path 80 to its at least one water outlet opening 36. The at least one water outlet opening 36 of the silencer 43 also serves to remove any spray water that may have penetrated into the silencer 43 via the at least one regeneration air outlet opening 34.

[0112] The regeneration process is terminated when a predetermined sufficiently large regeneration compressed air volume has flowed through the drying agent 41 of the air dryer 40 in order to be able to use it for a further air drying phase.

[0113] Of great importance for the inventive design of the compressed air generating device 2.7 is the flow path of the liquid coolant supplied by the first external cooling device 82. This coolant is cooled to a predetermined temperature in the first external cooling device 82 and supplied to the compressed air generating device 2.7 via a coolant supply line Kin. The cooling activity of the first external cooling device 82 is controlled and regulated by the control and regulating device 28. In a preferred control of the coolant temperature, the current actual temperature of the coolant is measured with a first temperature sensor 73 at the outlet of the first external cooling device 82, and then the coolant temperature is regulated to a predetermined setpoint value of the coolant temperature. For this purpose, the first temperature sensor 73 is connected to the control and regulating device 28 via the data and / or sensor line 59.

[0114] The coolant flows from the first external cooling device 82 through a coolant inlet opening 12 into the compressed air generation device 2.7 and into the compressed air cooling module 92. The coolant then flows through a first coolant line KL1 into the aftercooler 22, where it cools the compressed air generated by the compressor 4 as much as possible. Since the coolant is first fed into the aftercooler 22, the lowest temperature of the coolant within the compressed air generation device 2.7 can be utilized. As a result, the compressed air is comparatively cooled before it enters the air dryer 40, as a result of which some of the entrained air humidity condenses and is at least partially separated in the aftercooler 22. The condensed water is also fed into the collection area 49 of the air dryer 40 and from there discharged into the environment either directly or via the silencer 43.This process removes a lot of moisture from the compressed air before it reaches the air dryer 40. This is even more so the lower the temperature of the coolant.

[0115] As a result, the drying agent 41 of the air dryer 40 needs to be dried less frequently in regeneration processes compared to conventional compressed air generation devices, or such regeneration processes can be carried out with a smaller volume of regeneration compressed air than usual. As a result, more of the dry compressed air stored in the compressed air reservoir 45 is available for the compressed air consumers 51, 52, so that the electric motor 24 of the compressor 4 of the compressed air generation device 2.7 needs to be operated less frequently. As a result, when such a compressed air generation device 2.7 is arranged and operated in a vehicle, for example, the consumption of electrical energy is reduced, which reduces the vehicle's exhaust emissions and thus its CO emissions.

[0116] The frequency of the regeneration processes or the respectively required regeneration compressed air volume can therefore be lower the lower the coolant temperature at the inlet of the aftercooler 22. It is therefore advantageous if the control of the actuation frequency and / or the actuation duration of the regeneration switching valve, designed as the first 3 / 2-way solenoid valve 72, is also carried out by means of the control and regulating device 28 as a function of the coolant temperature. For this purpose, as already briefly mentioned, according to the exemplary embodiment shown in Fig. 8, a first temperature sensor 73 is arranged in the region of the outlet of the external cooling device 82 or in the region of the coolant inlet opening 12, by means of which the temperature of the liquid coolant can be measured.Typically, such a temperature sensor 73 is already part of the first external cooling device 82, so its use does not incur any additional manufacturing costs. The temperature measurements thus obtained can be transmitted to the control and regulating unit 28 via the aforementioned data and / or sensor line 59. The control and regulating unit 28 then controls and regulates the regeneration of the drying agent 41 of the air dryer 40, taking into account the current coolant temperature, directly via the actuation frequency and / or the actuation duration of the first 3 / 2-way solenoid valve 72 and indirectly via the pressure-controlled 2 / 2-way switching valve 39.

[0117] Fig. 8 also shows alternative solutions, according to which the temperature of the coolant can be measured at the coolant inlet of the aftercooler 22 by means of a second temperature sensor 73' and / or at the coolant outlet of the aftercooler 22 by means of a third temperature sensor 73". These temperature sensors 73', 73" are then also connected to the control and regulating device 28 via the data and / or sensor line 59. The data and / or sensor line 59, which is connected to the respective temperature sensor 73, 73', 73", can also, unlike as shown in Fig. 8, be arranged completely within the compressed air generation device 2.7.

[0118] With such a control system, it should also be noted that the temperature of the coolant can fluctuate during operation of the compressed air generation device 2.7. This can be caused by different load conditions of the vehicle and its systems and / or by rapidly changing ambient temperatures. Since the current temperature of the coolant is measured by the first temperature sensor 73 in most vehicles anyway for the control of the aforementioned first external cooling device 82, its current value is available to the control and regulating unit 28 via the aforementioned data and / or sensor line 59 of a CAN bus. Based on the current value of the coolant temperature, the control and regulating unit 28 can therefore quickly control and regulate the actuation duration of the 3 / 2-way solenoid valve 72 and thus the frequency and duration of a regeneration process on the dryer 40 at any time, depending on the temperature.

[0119] Since in most vehicles currently on the road the ambient temperature of the vehicle is also measured by means of an ambient temperature sensor 74 and displayed with a display element, the ambient temperature is also available to the control and regulating unit 28 via the data and / or sensor line 59 of the CAN bus for controlling and regulating the actuation duration of the first 3 / 2-way solenoid valve 72 and thus for controlling and regulating the frequency and duration of a regeneration process on the air dryer 40.

[0120] The ambient temperature of the vehicle is of particular importance for the control and regulation of the regeneration processes because, after being dried in the dryer 40, the compressed air cools further to the temperature of the compressed air reservoir 45 or the compressed air consumers 51, 52, which generally have the ambient temperature. During this further cooling process, the relative humidity in the compressed air increases again. To prevent corrosion processes or even water condensing and freezing into ice due to excessive humidity in the compressed air reservoirs and compressed air consumers at low ambient temperatures compared to the coolant temperature, the degree of dryness of the compressed air must ideally also take the current ambient temperature into account.

[0121] This degree of drying can be adjusted via the volume of regeneration compressed air used during a regeneration process and / or via the frequency of regeneration processes within a given period of time. If, for example, an actually too large volume of regeneration compressed air is used during a regeneration process, the drying agent 41 will be drier than required according to previously known practice. During a subsequent conveying process, the compressed air passed through the air dryer 40 will therefore lose more moisture than previously necessary, whereby the compressed air has a higher degree of drying when leaving the air dryer 40. During a subsequent further cooling of the compressed air in a compressed air tank or in a compressed air consumer, the degree of drying of the compressed air is then advantageously uncritically high, so that condensation and possible ice formation do not occur there during further cooling of the compressed air.

[0122] Thus, the control and regulating unit 28 controls and regulates the regeneration compressed air volume and / or the frequency of the regeneration processes at a constant ambient temperature depending on the coolant temperature, and also controls and regulates the regeneration processes at a constant coolant temperature depending on the ambient temperature. If both the ambient temperature and the coolant temperature change, the duration and / or frequency of the regeneration processes are controlled and regulated depending on the difference between the two temperatures.

[0123] If such a control is omitted, the volume of regeneration compressed air required for a regeneration process must also cover the worst-case scenario, i.e., take into account the highest coolant temperature expected during operation of the compressed air generation device 2.7. This would ensure that such a regeneration process for the desiccant 41 would always be carried out with a previously determined maximum regeneration compressed air volume.

[0124] The further use of the liquid coolant will now be described: After the liquid coolant has flowed through the aftercooler 22, it reaches the aforementioned intercooler 20 via a second coolant line KL2. There, it cools the compressed air pre-compressed by the first air compressor 16. After cooling the pre-compressed compressed air in the intercooler 20, the liquid coolant is fed via a third coolant line KL3 to a cooling device 25 of the electric motor 24. There, the coolant cools, for example, the stator of the electric motor 24.

[0125] The coolant then flows through a fourth coolant line KL4 to a cooling device 48 of the second air compressor 18 of the compressor 4, which is thereby cooled during its compression operation. The coolant then flows through a fifth coolant line KL5 to a cooling device 27 of the inverter 26 to cool the inverter 26 as well. The coolant is then conducted through a sixth coolant line KL6 to a cooling device 46 of the first air compressor 16 of the compressor 4 to cool the inverter. Finally, the heated coolant is conducted through a coolant outlet opening 14 from the compressor module 90 and from the housing 6 of the compressed air generation device 2.7 via a coolant discharge line Kout to the first external cooling device 82.Investigations have shown that the described, comparatively strong cooling of the compressed air in the aftercooler 22 has no negative impact on the operation of the compressed air generation device 2.7. Further advantages are even apparent. This will be explained using the following example:

[0126] In this case, a compressed air generating device 2.7 designed according to the invention is installed in a truck, and for cooling, it uses the liquid coolant from the cooling system that also cools the truck's internal combustion engine and serves as a heat source for an interior heater. During a cold start of the internal combustion engine, i.e., when it is started at a very low ambient temperature, it is advantageous with regard to the operating characteristics of a vehicle battery, low exhaust emissions from the truck, and the provision of warm air for an interior heater of the truck if the temperature of the cooling system of the internal combustion engine is quickly increased above the ambient temperature. This is because, during the cold start of the internal combustion engine, the electrically operated compressed air generating device 2.7 is put into operation for the operationally necessary generation of compressed air, this is cooled as far as possible by the liquid coolant. The waste heat thus extracted from the compressed air generation device 2.7, in particular the heat generated by the operation of the electric motor 24, the inverter 26 and the two air compressors 16, 18, then advantageously also indirectly serves to relieve the load on the vehicle battery by heating the liquid coolant. During the cold start period and a short warm-up phase of the truck, temperatures at which water ice can form can also be accepted at the aftercooler 22 and at the inlet of the air dryer 40. Since the warm-up phase is comparatively short, any water ice formed at the aftercooler 22 and at the inlet of the air dryer 40 will evaporate during the subsequent normal operating phase and be absorbed into the compressed air as air humidity.

[0127] The compressed air generating devices 2.3, 2.4, 2.5, 2.6, 2.8, 2.9 shown in Figures 1 to 7 also largely have the design features explained in connection with the compressed air generating device 2.7 according to Figure 8 and operate according to the described method. According to the invention, all of the compressed air generating devices 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 shown in Figures 1 to 8 are provided with the air cooler 22, which is arranged as the last air cooler upstream of the air dryer 40 in the direction of flow of the compressed air, being the first through which the coolant can flow, as seen in the direction of flow of the coolant.

[0128] All compressed air generating devices 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 shown in Figures 1 to 8 also have the further advantageous special feature that the control and regulating device 28 is designed and arranged in such a way that the operation of the electric motor 24, a drying operation and a regeneration operation of the air dryer 40, and the operation of a multi-circuit protection valve 50 can be controlled and regulated with it.

[0129] At this point, with reference to Figures 4 to 8, it is pointed out that the silencer 43 or the silencer module 96 is connected or connectable to the housing 6 of the respective compressed air generating device 2.3 to 2.7 and the lines there, but is not structurally integrated into this housing 6.

[0130] The embodiment of a compressed air generating device 2.3 having the features of the invention shown in Fig. 4, like the first embodiment of the compressed air generating device 2.7 according to Fig. 8 presented at the outset, has a separate compressed air cooling module 92 which is arranged between the compressor module 90 and the dryer module 94. In contrast to the compressed air generating devices 2.7, 2.8, 2.9 according to Figs. 1, 2 and 8, the compressed air generating devices 2.3 to 2.6 according to Figs. 4 to 7 have an air inlet 8* for sucking in ambient air L, which is not formed on the compressor module 90 but on the silencer 43 or on the silencer module 96. In order to save manufacturing costs, this air inlet 8* is identical to the at least one regeneration air outlet opening 34, which is only required by the respective compressed air generating device when it is operated in the regeneration module.For the remaining time, i.e. for most of the operating time, this at least one regeneration air outlet opening 34 serves as an air inlet 8*, through which ambient air L can be sucked into the first air compressor 16.

[0131] In these compressed air generating devices 2.3 to 2.6, as shown in Figures 4 to 7, the ambient air L flows from the alternately usable opening 8*, 34 in the silencer 43 or silencer module 96 via the sound-damping material 44 arranged there and the intake line DL to the inlet of the first air compressor 16, where it is compressed into compressed air in a first compression process. The compressed air then follows the flow path already explained in the description of the compressed air generating device 2.7 according to Figure 8.

[0132] The further development of the compressed air generation device 2.4 shown in Fig. 5 is largely identical to the compressed air generation device 2.3 according to Fig. 4. Since the suction and passage of ambient air L through the sound-damping material 44 of the silencer 43 could result in the latter being undesirably heavily contaminated with penetrating splash water, air humidity, and dirt particles, a water and particle separator 88 is arranged in or on the silencer 43 in the compressed air generation device 2.4. The water W filtered out of the sucked-in ambient air L by this water and particle separator 88 is guided, together with filtered-out dirt particles, to the water outlet opening 36 of the silencer 43, where it is discharged into the environment.

[0133] Fig. 6 shows a further variant of a compressed air generating device 2.5 incorporating the features of the invention. This differs from the compressed air generating device 2.3 shown in Fig. 4 only in that the multi-circuit protection valve 50 is not part of the dryer module 94. As Fig. 6 illustrates, the multi-circuit protection valve 50 can be arranged and operated remotely from the dryer module 94, on the compressed air generating device 2.5, or remotely from it. For this purpose, the multi-circuit protection valve 50 has pneumatic connecting means 62 on the inlet side, via which the multi-circuit protection valve 50 is detachably connected to the fifth compressed air line DL5 of the dryer module 94 described above. In addition, the multi-circuit protection valve 50 has pneumatic connecting means 66 on the output side, via which the multi-circuit protection valve 50 is detachably connected to the sixth, seventh and eighth compressed air lines DL6, DL7, DL8.As already described, these compressed air lines DL6, DL7, DL8 lead to compressed air consumers 51, 52 and to at least one compressed air reservoir 45. In addition, the multi-circuit protection valve 50 has electrical connecting means 64 by means of which the multi-circuit protection valve 50 is detachably connected to electrical connecting means 68 of the control and regulating device 28.

[0134] The pneumatic connecting means 62, 66 are preferably designed as compressed air connection sockets into which compressed air plugs can be removably inserted. These compressed air plugs are arranged at the ends of the compressed air lines DL5, DL6, DL7, DL8. These compressed air lines DL5, DL6, DL7, DL8 can be designed as flexible compressed air lines.

[0135] The electrical connection means 64 on the multi-circuit protection valve 50 is preferably designed as an electrical socket. An electrical plug of a sensor line 56 can be releasably inserted into this electrical socket. At its other end, the sensor line 56 has, for example, a second electrical plug, which can also be releasably inserted into an associated electrical connection means 68, designed as a socket, on the control and regulating device 28.

[0136] Due to the described structure of the compressed air generating device 2.5, the multi-circuit protection valve 50 can also be arranged remotely from the compressed air generating device 2.5, so that in the event of damage to the compressed air generating device 2.5, it does not have to be removed from the compressed air system of a vehicle for repair purposes.

[0137] At this point, it should be mentioned that the control and regulating device 28 is designed and connected to the other components of the compressed air generation device 2.5 via sensor lines and control lines in such a way that the control and regulating device 28 can control and regulate the operation of the inverter 26 and thus the operation of the electric motor 24, as well as the dryer operation and the regeneration operation of the air dryer 40. In addition, the control and regulating device 28 at least indirectly controls and regulates the operation of the multi-circuit protection valve 50.

[0138] The control and regulating unit 28 can be structurally integrated, for example, into the inverter 26 or into the multi-circuit protection valve 50. This prevents the control and regulating unit 28 from remaining on the vehicle in the repair case described.

[0139] Furthermore, Fig. 7 shows a further embodiment of a compressed air generation device 2.6 having the features of the invention. As in the embodiment shown in Fig. 5, it is also provided here that the multi-circuit protection valve 50 can be separated from the other components of the compressed air generation device 2.6 and can be operated remotely from these components. For this purpose, the control and regulating device 28 and the multi-circuit protection valve 50 have electrical connecting means 64, 68, which are at least indirectly detachably connected to one another via at least one flexible electrical line 56, 102. Furthermore, the multi-circuit protection valve 50 has pneumatic connecting means 62, which are at least indirectly detachably connected to the outlet of the air dryer 40 via at least one flexible pneumatic line 106.

[0140] Accordingly, the compressed air generating device 2.6 comprises an electric motor 24 and two air compressors 16, 18 that can be driven by the electric motor 24 and operate sequentially. The compressed air generating device 2.6 also has an air inlet 8* through which ambient air L can be drawn in by means of the first air compressor 16. Furthermore, an intercooler 20 and an aftercooler 22 are provided, the inlet of the intercooler 20 being pneumatically connected to the outlet of the first air compressor 16, the outlet of the intercooler 20 being pneumatically connected to the inlet of the second air compressor 18, and the outlet of the second air compressor 18 being pneumatically connected to the inlet of the aftercooler 22. An air dryer 40 is also provided, the inlet of which is pneumatically connected to the outlet of the aftercooler 22.For supplying a coolant, a coolant inlet opening 12 is provided, through which a liquid coolant can be supplied to the intercooler 20 and the aftercooler 22 from a first external cooling device 82. Heated coolant can be discharged to the first external cooling device 82 via a coolant outlet opening 14 and a coolant discharge line Kout.

[0141] The compressed air generation device 2.6 according to Fig. 7 supplies compressed air to the multi-circuit protection valve 50, via which the outlet of the air dryer 40 is pneumatically connected to at least one external compressed air reservoir 45 and external compressed air consumers 51, 52. Furthermore, a control and regulating device 28 is provided, which is connected to the multi-circuit protection valve 50 and sensors arranged there via at least one sensor line 56.

[0142] In this compressed air generation device 2.6 according to Fig. 7, it is provided that a dryer module 94* comprising the air dryer 40 has at least one electrical socket 100 and at least one pneumatic socket 104. The electrical socket 100 of the dryer module 94* is connected on the output side to the electrical socket 68 on the control and regulating device 28 via the aforementioned sensor line 56. An electrical plug of an electrical connecting line 102 is removably inserted into the electrical socket 100 of the dryer module 94 on the input side. This electrical connecting line 102 has a second plug, which is removably inserted into the electrical socket 64 of the multi-circuit protection valve 50.

[0143] The pneumatic connector socket 104 of the dryer module 94* is pneumatically connected to the fifth compressed air line DL5, through which dry compressed air coming from the air dryer 40 can be conducted to the compressed air consumers 51, 52 and to the compressed air reservoir 45. A plug of a pneumatic connecting line 106 is removably inserted into this pneumatic connector socket 104 of the dryer module 94*. This pneumatic connecting line 106 has a second plug, which is removably inserted into the pneumatic connector socket 62 of the multi-circuit protection valve 50.

[0144] In the compressed air generating device 2.6 according to Fig. 7, the

[0145] Multi-circuit protection valve 50 is comparatively far from the other components of the

[0146] A compressed air generating device 2.6 can be arranged. The feasible distance is determined in particular by the maximum practical length of the electrical connecting line 102 and the pneumatic connecting line 106. Such a compressed air generating device 2.6 is used, for example, in a vehicle combination consisting of a towing vehicle and several trailer vehicles, in which the multi-circuit protection valve 50 is arranged on one of the trailer vehicles, but the core components of the compressed air generating device 2.6 are located on the towing vehicle.

[0147] This makes it possible, in particular, to keep the compressed air lines DL6, DL7, DL8 leading from the multi-circuit protection valve 50 to the compressed air consumers 51, 52 and the at least one compressed air reservoir 45 comparatively short. This reduces manufacturing costs and the risk of line damage due to the reduced overall line length. Furthermore, the air dryer module 94* can be designed to be narrower, which can be advantageous in confined spaces on a vehicle.

[0148] As indicated in Fig. 7, according to an alternative embodiment, the multi-circuit protection valve 50, with all of its sensors and electromagnetic switching valves arranged therein, can be connected to a central control unit 110 of the vehicle via a single electrical line 108. In this variant, the central control unit 110 would then also be electrically connected to the first 3 / 2-way solenoid switching valve 72 or to the two 2 / 2-way solenoid switching valves used for it via at least one control line 112. Such a central control unit 110 of the vehicle would then also assume all other tasks of the described control and regulating unit 28.

[0149] The variant of a compressed air generating device 2.8 having the features of the invention shown in Fig. 1 does not show all the details of the air dryer 40 and the control means arranged there for realizing a drying operation and a regeneration operation, since these are not important for the description of this device variant and would only disturb the clarity of the illustration.

[0150] Accordingly, the compressed air generation device 2.8 comprises a control and regulating device 28, an electric motor 24, two air compressors 16, 18 which can be driven by the electric motor 24 and operate one after the other, an air inlet 8 through which ambient air L can be sucked in by means of the first air compressor 16, a first air cooler designed and arranged as an intercooler 20, and a second air cooler designed and arranged as an aftercooler 22, wherein the inlet of the intercooler 20 is pneumatically connected to the outlet of the first air compressor 16, wherein the outlet of the intercooler 20 is pneumatically connected to the inlet of the second air compressor 18, and wherein the outlet of the second air compressor 18 is pneumatically connected to the inlet of the aftercooler 22, as well as an air dryer 40, whose inlet is pneumatically connected to the outlet of the aftercooler 22, and having a coolant inlet opening 12,via which a liquid coolant can be supplied to the intercooler 20, the aftercooler 22, and other components of the compressed air generation device, as well as a coolant outlet opening 14, through which heated coolant can be discharged. And in this compressed air generation device 2.8, the invention also provides that the aftercooler 22, which is arranged as the last air cooler upstream of the air dryer 40 in the direction of flow of the compressed air, is the first through which the coolant can flow, as seen in the direction of flow of the coolant.

[0151] In the compressed air generation device 2.8 according to Fig. 1, as a further development of the subject matter of the invention, it is provided that the coolant inlet of the aftercooler 22 is connected to the coolant inlet opening 12 via a first coolant line KL1, that the coolant outlet of the aftercooler 22 is connected to a coolant inlet of the intercooler 20 via a second coolant line KL2, that the coolant outlet of the intercooler 20 is connected to a coolant inlet of a dryer module cooler 40.1 via a seventh coolant line KL7, that a coolant outlet of the dryer module cooler 40.1 is connected to the coolant inlet of the electric motor 24 via an eighth coolant line KL8, that the coolant outlet of the electric motor 24 is connected to the coolant inlet of the second air compressor 18 via a fourth coolant line KL4, that the coolant outlet of the second air compressor 18 is connected via a fifth coolant line KL5 to the coolant inlet of an inverter 26, which serves to control and regulate the electric motor 24 by means of the control and regulating device 28, that the coolant outlet of the inverter 26 is connected to the coolant inlet of the first air compressor 16 via a sixth coolant line KL6, and that the coolant outlet of the first air compressor 16 is connected to the coolant outlet opening 14 of the compressed air generating device 2.8 via a coolant discharge line Kout.The coolant inlet opening 12 and the coolant outlet opening 14 are hydraulically connected to the aforementioned first external cooling device 82. Furthermore, a first temperature sensor 73 is arranged at the outlet of the first external cooling device 82. This first temperature sensor 73 is connected to the control and regulating unit 28 via a data line and / or sensor line 59, and by means of which the temperature of the coolant at the outlet of the first external cooling device 82 can be measured.

[0152] A particularly advantageous feature of this embodiment of the compressed air generation device 2.8 is that the air dryer 40, or components thereof, can also be actively cooled by means of the liquid coolant via the dryer module cooler 40.1. For example, the housing of the air dryer 40 can be cooled, forcing the compressed air reaching the air dryer 40 to release humidity through condensation even before flowing through the drying agent 41. The condensed water W then preferably reaches the collection area 49 of the air dryer 40, which is shown in Figures 4 to 8, and is ultimately discharged to the outside environment.

[0153] The last variant of a compressed air generation device 2.9 presented here, incorporating the features of the invention, is schematically illustrated in Figures 2 and 3. Figure 3 shows, in a simplified enlarged detail of the compressed air generation device 2.9, three external cooling devices 82, 120, 122, the intercooler 20, the aftercooler 22, and the associated lines carrying the liquid coolant and the compressed air. The three cooling devices 82, 120, 122 can be used alternatively or additionally, as needed, to cool the compressed air and the components of the compressed air generation device 2.9.

[0154] The compressed air generation device 2.9 comprises the basic components mentioned several times, without needing to describe them again here. However, what is important about the compressed air generation device 2.9 is that the three external cooling devices 82, 120, 122 can be connected to it, which can be used as needed under the control of the control and regulating unit 28.

[0155] Thus, in a first operating mode, the compressed air generating device 2.9 according to Figures 2 and 3 can only use the first external cooling device 82 to cool its components and the compressed air, namely when the temperature of the liquid coolant is lower than the temperature of the compressed air generated by the two air compressors 16, 18.

[0156] For this purpose, it is provided that the coolant inlet opening 12 is hydraulically connected to the first external cooling device 82, that a first cooling switching valve 130 is arranged in a first coolant line KL1 running from the coolant inlet opening 12 to the coolant inlet of the aftercooler 22, that the first cooling switching valve 130 is designed as a 2 / 2-way solenoid switching valve which is connected for control purposes to the control and regulating device 28, and that by means of the first cooling switching valve 130, depending on its switching position, the first coolant line KL1 can be shut off or opened at a low coolant temperature as described.

[0157] However, it is also possible that if the temperature of the liquid coolant is higher than the temperature of the compressed air, the coolant is not used to cool the compressed air in the aftercooler 22 and intercooler 20, but is used to cool the electric motor 24, the inverter 26 and the two air compressors 16, 18.

[0158] The control for utilizing the coolant of the first external cooling device is carried out by means of the control and regulating unit 28, which uses the measured values ​​of the first temperature sensor 73 for this purpose and can control an associated electromagnetic solenoid valve (not shown in the figures) arranged in a separate coolant line to bypass the aftercooler 22 and the intercooler 20. This separate coolant line connects the coolant inlet opening 12 to the inlet of the cooling device 25 of the electric motor 24. The separate solenoid valve is designed, for example, as a 2 / 2-way solenoid valve.When the first cooling switching valve 130 is closed, it is opened when the temperature of the coolant of the first external cooling device 82 is higher than the temperature of the compressed air in the aftercooler 22, but lower than the temperature of the cooling device 25 of the electric motor 24, the cooling device 27 of the inverter 26 and / or the cooling device 46, 48 of the first air compressor 48 and / or the second air compressor 18. This ensures that the electric motor 24, the inverter 26 and the two air compressors 16, 18 are supplied with the liquid coolant for cooling them by the first external cooling device 82 even when the coolant temperature is higher than the temperature of the compressed air at the aftercooler 22.

[0159] If the temperature of the coolant at the outlet of the first external cooling device 82 and / or at the inlet of the aftercooler 22 is too high to cool the compressed air in the aftercooler 22, it is provided that the outlet of the first air compressor 16 can be connected to an inlet of a second external cooling device 120 via a second cooling switching valve 132 designed as a 3 / 2-way solenoid valve, that the second cooling switching valve 132 is connected for control purposes to the control and regulating unit 28, and that the outlet of the second external cooling device 120 is pneumatically connected to the inlet of the second air compressor 18. The compressed air then passes from the outlet of the second air compressor 18 to the aftercooler 22 and from there to the air dryer 40. Since the aftercooler 22 is passive with regard to compressed air cooling in this operating situation, its flow through it does not increase the temperature of the compressed air.

[0160] In the event that the cooling capacity of the second external cooling device 120 is insufficient to cool the compressed air to the desired extent, a third external cooling device can be activated as an alternative. A further embodiment provides that the output of the second air compressor 18 can be connected to an inlet of a third external cooling device 122 via a third cooling switching valve 134 designed as a 3 / 2-way solenoid valve, that the third cooling switching valve 134 is connected for control purposes to the control and regulating unit 28, and that the output of the third external cooling device 122 is connected to the inlet of the air dryer 40.It is evident that when using the second external cooling device 120 and the third external cooling device 122, the temperature of the compressed air can be adjusted to a desired value, thereby achieving a very extensive condensation of humidity in the compressed air even before it reaches the air dryer 40 or its drying material 41. The second external cooling device 120 and the third external cooling device 122 can be designed as air-to-air heat exchangers. As Fig. 3 illustrates in the area of ​​the marking area A there, the compressed air is guided in opposite directions in the lines leading to these two external cooling devices 120, 122.

[0161] A method for using the compressed air generating device 2.8 according to Fig. 1 provides that the cooling liquid coming from the coolant outlet of the intercooler 20 is not conveyed directly, but via a dryer module cooler 40.1 to the coolant inlet of the electric motor 24, and that the dryer module cooler 40.1 cools at least components of the air dryer 40, such as its housing.

[0162] A method for using the compressed air generating device 2.9 according to Fig. 2 and Fig. 3 provides that the temperature of the cooling liquid is measured at the outlet of the first external cooling device 82 or at the inlet of the aftercooler 22, and that when the determined temperature of the coolant has reached or exceeded a previously defined high first limit value, the transport of compressed air from the outlet of the first air compressor 16 no longer takes place via the intercooler 20 but via a second external cooling device 120 to the inlet of the second air compressor 18.

[0163] Furthermore, according to the method, it can be provided that the temperature of the cooling liquid is measured at the outlet of the first external cooling device 82 or at the inlet of the aftercooler 22, and that when the temperature of the coolant has reached or exceeded a previously defined second limit value which is greater than the first limit value, the transport of compressed air coming from the outlet of the first air compressor 16 does not take place via the intercooler 20 but rather via the second external cooling device 120 to the inlet of the second air compressor 18, and that then additionally the transport of compressed air coming from the outlet of the second air compressor 18 is not conducted via the aftercooler 22 but rather via a third external cooling device 122 to the outlet of the aftercooler 22 or to the inlet of the air dryer 40.

[0164] Accordingly, the first external cooling device 82 is not used to cool the compressed air, but the two other external cooling devices 120, 122 are. Furthermore, in addition to the intercooler 20, the aftercooler 22 is also bypassed by the compressed air.

[0165] Finally, according to the method, as indicated, it can be provided that even if no compressed air is passed through the intercooler 20 and / or the aftercooler 22, the liquid coolant of the first external cooling device 82 is passed through the cooling devices 25, 27, 46, 48 of the electric motor 24, the inverter 26 and the two air compressors 16, 18.

[0166] List of reference symbols (part of the description)

[0167] 2.3 Compressed air generation device (first embodiment)

[0168] 2.4 Compressed air generation device (second embodiment)

[0169] 2.5 Compressed air generation device (third embodiment)

[0170] 2.6 Compressed air generation device (fourth embodiment)

[0171] 2.7 Compressed air generation device (fifth embodiment)

[0172] 2.8 Compressed air generation device (sixth embodiment)

[0173] 2.9 Compressed air generation device (seventh embodiment)

[0174] 4 Compressor

[0175] 6 Housing of the compressed air generation device

[0176] 8 Air inlet (first embodiment)

[0177] 8* Air inlet (second embodiment), opening in the silencer

[0178] 10 Compressed air outlet opening

[0179] 12 Coolant inlet opening

[0180] 14 Coolant outlet

[0181] 16 First air compressor

[0182] 18 Second air compressor

[0183] 20 intercoolers, air coolers

[0184] 22 aftercoolers, air coolers

[0185] 23 Drying air flow in the air dryer

[0186] 24 electric motor

[0187] 25 Cooling device of the electric motor

[0188] 26 inverters

[0189] 27 Inverter cooling device

[0190] 28 Control and regulating device

[0191] 29 First check valve

[0192] 30 First drive shaft

[0193] 32 Second drive shaft

[0194] 34 Regeneration air outlet opening, opening in the silencer

[0195] 36 Water outlet opening of the silencer

[0196] 39 Pressure-controlled 2 / 2-way switching valve, drain valve on the air dryer

[0197] 40 air dryers .1 dryer module cooler

[0198] Desiccant in the air dryer

[0199] Regeneration air outlet of the air dryer

[0200] silencer

[0201] Sound-absorbing material

[0202] Compressed air storage

[0203] Cooling device of the first air compressor

[0204] Cooling device of the second air compressor

[0205] Air dryer water collection area

[0206] Multi-circuit protection valve

[0207] First compressed air consumer

[0208] Second compressed air consumer

[0209] Control line

[0210] Control cable from the control unit to the 3 / 2-way switching valve 72 Sensor cable from the control unit to the multi-circuit protection valve Low-voltage cable

[0211] high-voltage line

[0212] Data line and / or sensor line, CAN bus

[0213] Inlet-side pneumatic connecting devices on the multi-circuit protection valve

[0214] Electrical connection elements on the multi-circuit protection valve

[0215] Output-side pneumatic connecting devices on the multi-circuit protection valve

[0216] Electrical connection means on the control and regulation unit regeneration compressed air inlet of the air dryer

[0217] Regeneration switching valve, first 3 / 2-way solenoid valve

[0218] First temperature sensor (measuring coolant temperature) ' Second temperature sensor (measuring coolant temperature) “ Third temperature sensor (measuring coolant temperature)

[0219] Fourth temperature sensor, (measures ambient temperature)

[0220] aperture

[0221] Second check valve

[0222] Regeneration compressed air flow in the air dryer

[0223] Exhaust air path in the silencer

[0224] Water separation path in the silencer

[0225] External cooling device 88 separators, water and particle separators

[0226] 90 compressor module

[0227] 92 Compressed air cooling module

[0228] 94 Dryer module

[0229] 96 silencer module

[0230] 100 Electrical connector socket on the dryer module

[0231] 102 Electrical connecting cable

[0232] 104 Pneumatic connector socket on the dryer module

[0233] 106 Pneumatic connecting line

[0234] 108 Electrical cable from the multi-circuit protection valve to the control unit 110

[0235] 110 Central control unit of a vehicle

[0236] 112 Control line from control unit 110 to solenoid valve 72

[0237] 120 Second external cooling device

[0238] 122 Third external cooling device

[0239] 130 First cooling switching valve, 2 / 2-way solenoid valve

[0240] 132 Second cooling switching valve, second 3 / 2-way solenoid switching valve

[0241] 134 Third cooling switching valve, third 3 / 2-way solenoid switching valve

[0242] 136 control lines from the control and regulation unit to the cooling switching valves

[0243] A Marking area

[0244] AL regeneration exhaust air

[0245] DL intake line for ambient air

[0246] DL1 First compressed air line

[0247] DL2 Second compressed air line

[0248] DL3 Third compressed air line

[0249] DL4 Fourth compressed air line

[0250] DL5 Fifth compressed air line

[0251] DL5a regeneration line

[0252] DL5b First line branch

[0253] DL5c Second line branch

[0254] DL6 Sixth compressed air line

[0255] DL7 Seventh compressed air line

[0256] DL8 Eighth compressed air line

[0257] DL1.1 Ninth compressed air line

[0258] DL2.1 Tenth compressed air line DL3.1 Eleventh compressed air line

[0259] DL4.1 Twelfth compressed air line

[0260] KL1 First coolant line

[0261] KL2 Second coolant line

[0262] KL3 Third coolant line

[0263] KL4 Fourth coolant line

[0264] KL5 Fifth coolant line

[0265] KL6 Sixth coolant line

[0266] KL7 Seventh coolant line

[0267] KL8 Eighth coolant line

[0268] Kin coolant supply line

[0269] Kout coolant discharge line

[0270] L Ambient air

[0271] W Water

Claims

Patent claims 1. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9), comprising a control and regulating device (28), at least one controllable and regulating electric motor (24), at least one air compressor (16, 18) driven by the electric motor (24), an air inlet (8, 8*) through which ambient air (L) can be drawn into the at least one air compressor (16, 18), at least one air cooler (20, 22) which is connected or connectable to the outlet of the at least one air compressor (16, 18), an air dryer (40) whose inlet is connected to the outlet of the at least one air cooler (20, 22), and a coolant inlet opening (12) through which a liquid coolant is supplied to the at least one air cooler (20, 22) and other components of the compressed air generating device. is supplied, and with a coolant outlet opening (14) through which heated coolant can be discharged from the compressed air generating device, characterized in thatthat the air cooler (22), which is arranged as the last air cooler before the air dryer (40) in the direction of flow of the compressed air, is the first to be able to flow through the coolant in the direction of flow of the coolant.

2. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9), with a control and regulating device (28), with an electric motor (24), with two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, with an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), with a first air cooler designed and arranged as an intercooler (20) and with a second air cooler designed and arranged as an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected or connectable to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22) is pneumatically connected or connectable to an air dryer (40),whose inlet is pneumatically connected to the outlet of the aftercooler (22), and with a coolant inlet opening (12) through which a liquid coolant can be supplied to the intercooler (20) as well as to the aftercooler (22) and other components of the compressed air generation device, and with a, Coolant outlet opening (14), through which heated coolant can be discharged, characterized in that the aftercooler (22), which is arranged as the last air cooler upstream of the air dryer (40) in the direction of flow of the compressed air, is the first part through which the coolant can flow in the direction of flow of the coolant.

3. Compressed air generating device (2.8) according to claim 2, characterized in that a coolant inlet of the aftercooler (22) is connected to the coolant inlet opening (12), that a coolant outlet of the aftercooler (22) is connected to a coolant inlet of the intercooler (20), that a coolant outlet of the intercooler (20) is connected to a coolant inlet of a dryer module cooler (40.1), that a coolant outlet of the dryer module cooler (40.1) is connected to a coolant inlet of the electric motor (24), that a coolant outlet of the electric motor (24) is connected to a coolant inlet of the second air compressor (18), that a coolant outlet of the second air compressor (18) is connected to a coolant inlet of an inverter (26), which serves to control and regulate the electric motor (24) by means of the control and regulating device (28), that a coolant outlet of the inverter (26) is connected to a coolant inlet of the first air compressor (16), and that a coolant outlet of the first air compressor (16) is connected to the coolant outlet opening (14).

4. Compressed air generation device (2.8) according to claim 3, characterized in that the dryer module cooler (40.1 ) is designed and arranged such that at least components of the air dryer (40) can be cooled with it.

5. Compressed air generating device (2.9) according to claim 1 or 2, characterized in that the coolant inlet opening (12) is hydraulically connected to a first external cooling device (82), that a first cooling switching valve (130) is arranged in a first coolant line (KL1) running from the coolant inlet opening (12) to the coolant inlet of the aftercooler (22), that the first cooling switching valve (130) is designed as a 2 / 2-way solenoid switching valve which is connected to the control and regulating device (28) for control purposes, and that The first coolant line (KL1) can be shut off or opened by means of the first cooling switching valve (130) depending on its switching position.

6. Compressed air generating device (2.9) according to one of claims 1 to 5, characterized in that the output of the first air compressor (16) can be connected to an input of a second external cooling device (120) via a second cooling switching valve (132) designed as a 3 / 2-way solenoid switching valve, that the second cooling switching valve (132) is connected to the control and regulating device (28) for control purposes, and that the output of the second external cooling device (120) is connected to the input of the second air compressor (18).

7. Compressed air generating device (2.9) according to one of claims 1 to 6, characterized in that the output of the second air compressor (18) can be connected to an input of a third external cooling device (122) via a third cooling switching valve (134) designed as a 3 / 2-way solenoid switching valve, that the third cooling switching valve (134) is connected to the control and regulating device (28) for control purposes, and that the output of the third external cooling device (122) is connected to the input of the air dryer (40).

8. Compressed air generating device (2.9), comprising a control and regulating device (28), an electric motor (24), two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, an air inlet (8) through which ambient air (L) can be drawn in by means of the first air compressor (16), a first air cooler designed and arranged as an intercooler (20), and a second air cooler designed and arranged as an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), and an air dryer (40) whose inlet is pneumatically connected to the outlet of the aftercooler (22). is, and with a coolant inlet opening (12),via which a liquid coolant is supplied to the intercooler (20), the aftercooler (22) and other components of the compressed air generation device, is supplyable, and with a coolant outlet opening (14) through which heated coolant can be discharged, characterized in that the aftercooler (22), which is arranged as the last air cooler upstream of the air dryer (40) in the direction of flow of the compressed air, is the first to be permeated by the coolant in the direction of flow of the coolant, that the coolant inlet opening (12) can be connected to a coolant outlet of a first external cooling device (82), that an outlet of the first air compressor (16) can be pneumatically connected to an inlet of the intermediate cooling (20) via a first compressed air line (DL1), and that a ninth compressed air line (DL1) is connected to this first compressed air line (DL1).1) is connected, which is pneumatically connectable to an inlet of a second external cooling device (120), that an outlet of the intercooler (20) is pneumatically connected via a second compressed air line (DL2) to an inlet of the second air compressor (18), that a tenth compressed air line (DL2.1) is connected to this second compressed air line (DL2), which is pneumatically connected to an outlet of the second external cooling device (120), that an inlet of the aftercooler (22) is pneumatically connectable via a third compressed air line (DL3) to an outlet of the second air compressor (18), that the third compressed air line (DL3) is connectable to an eleventh compressed air line (DL3.1), that the eleventh compressed air line (DL3.1) is pneumatically connected to the inlet of a third external cooling device (122), that the outlet of the third external cooling device (122) is pneumatically connected via a twelfth compressed air line (D4.1) is connected to a fourth compressed air line (DL4), and that this fourth compressed air line (DL4) connects an outlet of the aftercooler (22) to an inlet of the air dryer (40).

9. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8), with a control and regulating device (28), with an electric motor (24), with two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, with an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), with a first air cooler designed and arranged as an intercooler (20) and with a second air cooler designed and arranged as an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18). is connected, and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), to an air dryer (40) whose inlet is pneumatically connected to the outlet of the aftercooler (22), and to a coolant inlet opening (12) through which a liquid coolant can be supplied to the intermediate cooler (20) as well as to the aftercooler (22) and other components of the compressed air generation device, and to a coolant outlet opening (14) through which heated coolant can be discharged, characterized in that at least one temperature sensor (73, 73', 73") is provided, which is arranged for measuring the coolant temperature upstream of the coolant inlet and / or downstream of the coolant outlet of the air cooler (22) which is placed as the last air cooler upstream of the air dryer (40) in the direction of compressed air flow, and that this has at least one temperature sensor (73, 73',73") is connected to the control and regulating unit (28) via a data or sensor line (59).

10. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8), comprising a control and regulating device (28), an electric motor (24), two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), a first air cooler designed and arranged as an intercooler (20), and a second air cooler designed and arranged as an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22). pneumatically connected to an air dryer (40), the inlet of which is pneumatically connected to the outlet of the aftercooler (22),and with a coolant inlet opening (12) through which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22) and other components of the compressed air generation device, and with a coolant outlet opening (14) through which heated coolant can be discharged, characterized in that the aftercooler (22), which is arranged as the last air cooler upstream of the air dryer (40) in the direction of flow of the compressed air, is the first part through which the coolant can flow in the direction of flow of the coolant, and that at least one temperature sensor (73, 73', 73"), is present, which is connected to the control and regulating device (28) via a data or sensor line (59), that the temperature sensor (73, 73', 73") for measuring the coolant temperature is arranged before the coolant inlet or after the coolant outlet of the aftercooler (22), and that the control and regulating device (28) is designed in such a way that, in addition to the operation of the electric motor (24), a drying operation and a regeneration operation of the air dryer (40) as well as the operation of a multi-circuit protection valve (50) can be controlled and regulated with it.

11. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.9) according to one of the preceding claims, characterized in that a temperature sensor (73) for measuring the coolant temperature is arranged in front of the coolant inlet opening (12) of the compressed air generating device.

12. Compressed air generation device (2.4, 2.7) according to one of claims 9 or 10, characterized in that the temperature sensor (73') for measuring the coolant temperature is arranged directly in front of the coolant inlet of the aftercooler (22), which is arranged in the direction of flow of the compressed air as the last air cooler in front of the air dryer (40).

13. Compressed air generation device (2.4, 2.7) according to one of claims 9 or 10, characterized in that the temperature sensor (73") for measuring the coolant temperature is arranged as the next component downstream of the coolant outlet of the aftercooler (22), which is arranged as the last air cooler upstream of the air dryer (40) in the direction of flow of the compressed air.

14. Compressed air generation device (2.4, 2.7) according to one of claims 9 or 10, characterized in that a temperature sensor (73', 73") is arranged at both the coolant inlet and the coolant outlet of the aftercooler (22), which are connected to the control and regulating device (28) via signal technology.

15. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9) according to one of claims 1 to 14, characterized in that the at least one electric motor (24), the inverter (26), the two air compressors (16, 18), the intercooler (20), the aftercooler (22), the air dryer (40), the multi-circuit protection valve (50), which pneumatically connects the outlet of the air dryer (40) with at least one external compressed air storage tank (45) and external compressed air consumers (51, 52), and a silencer (43) are arranged in a cooperating manner, but separately in relation to each other.

16. Compressed air generating device (2.8, 2.9) according to one of claims 1 to 14, characterized in that the at least one electric motor (24), the inverter (26), the two air compressors (16, 18), the intercooler (20), the aftercooler (22), the air dryer (40), the multi-circuit protection valve (50), which pneumatically connects the outlet of the air dryer (40) with at least one external compressed air storage tank (45) and external compressed air consumers (51, 52), and a silencer (43) are arranged in or on a common housing (6).

17. Compressed air generation device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9) according to one of claims 1 to 16, characterized in that the control and regulating device (28, 110) is arranged separately or in or on the housing (6), that the control and regulating device (28) is connected to the inverter (26) for controlling and regulating the electric motor (24) via a first control line (54), that the control and regulating device (28) is connected to a 3 / 2-way solenoid valve (72) via a second control line (55), which serves to open or close a regeneration line (DL5a) that pneumatically connects the compressed air storage tank (45) and the air dryer (40) at least indirectly, and that the control and regulating device (28) is connected to the multi-circuit protection valve (50) via a sensor line (56).

18. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9) according to any one of claims 1 to 17, characterized in that a compressor module (90), a compressed air cooling module (92), a dryer module (94) and a silencer module (96) together with associated pneumatic, hydraulic and electrical lines are arranged in or on the housing (6), wherein the compressor module (90) connects the electrical motor (24), inverter (26), two air compressors (16, 18) and control and regulating device (28), wherein the compressed air cooling module (92) comprises the intercooler (20) and the aftercooler (22), wherein the dryer module (94) comprises the air dryer (40) and the multi-circuit protection valve (50), wherein the silencer module (96) comprises the silencer (43) with a sound-absorbing material (44), and wherein the silencer module (96) has at least one regeneration air outlet opening (34) for discharging regeneration compressed air into the environment.

19. Compressed air generating device (2.3, 2.4, 2.5, 2.6), with at least one electric motor (24), with at least one air compressor (16, 18) driven by the electric motor (24), with an air inlet (8*) through which ambient air (L) can be drawn in by means of the air compressor (16, 18), with at least one air cooler (20, 22) in which the air compressed by the air compressor (16, 18) can be cooled, with an air dryer (40) whose inlet is connected to the outlet of the at least one air cooler (20;22) is connected to a coolant inlet opening (12) through which a liquid coolant can be supplied to the air cooler (20, 22), and to a coolant outlet opening (14) through which heated coolant can be discharged, characterized in that the silencer (43) has at least one regeneration air outlet opening (34) for discharging regeneration exhaust air (AL) passed through it into the environment, that the at least one regeneration air outlet opening (34) serves as an air inlet (8*) for drawing in ambient air (L) to the at least one air compressor (16, 18) when no regeneration of the desiccant (41) of the air dryer (40) takes place, and that the ambient air (L) drawn in through the silencer (43) can be directed downstream behind the silencer (43) through an intake air line (DL) to the at least one air compressor (16, 18). is.; 20. Compressed air generating device (2.3, 2.4, 2.5, 2.6), comprising at least one electric motor (24), comprising two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, comprising an air inlet (8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), comprising an intercooler (20) and an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the The outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), to an air dryer (40) whose inlet is connected to the outlet of the aftercooler (22), and to a coolant inlet opening (12) through which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), and to a coolant outlet opening (14) through which heated coolant can be discharged, characterized in that the silencer (43) has at least one regeneration air outlet opening (34) for discharging regeneration exhaust air (AL) passed through it into the environment, and that the at least one regeneration air outlet opening (34) is closed when no regeneration of the desiccant (41) of the air dryer (40) takes place.as an air inlet (8*) for drawing in ambient air (L) towards the first air compressor (18), and that the ambient air (L) drawn in through the silencer (43) can be directed downstream behind the silencer (43) through an intake air line (DL) to the first air compressor (16).

21. Compressed air generating device (2.4) according to one of the preceding claims, characterized in that a separator (88) for separating water and particles is arranged in front of or in the silencer (43), which is designed and arranged in such a way that ambient air (L) drawn in through the at least one regeneration air outlet opening (34) serving as an air inlet (8*) can be freed from entrained water droplets and particles.

22. Compressed air generating device (2.5, 2.6), comprising at least one electric motor (24), at least one air compressor (16, 18) driven by the electric motor (24), an air inlet (8*) through which ambient air (L) can be drawn in by means of the air compressor (16, 18), at least one air cooler (20, 22) in which the air compressed by the air compressor (16, 18) can be cooled, an air dryer (40) whose inlet is connected to the outlet of the at least one air cooler (20, 22), a coolant inlet opening (12) through which a liquid coolant can be supplied to the air cooler (20, 22), a coolant outlet opening (14) through which heated coolant can be discharged, and a multi-circuit protection valve (50) which connects the outlet of the air dryer (40) to at least one external pneumatically connects compressed air storage (45) and external compressed air consumers (51, 52), as well as a control and regulating device (28), which is connected via at least one sensor line (56) to the multi-circuit protection valve (50) and sensors arranged therein, characterized in that the multi-circuit protection valve (50) is separable from the other components of the compressed air generation device and can be operated remotely from these components, that the control and regulating device (28) and the multi-circuit protection valve (50) have electrical connecting means (64, 68) which are detachably connected to each other via at least one flexible electrical line (56), and that the multi-circuit protection valve (50) has pneumatic connecting means (62) which are detachably connected at least indirectly to the outlet of the air dryer (40) via at least one flexible pneumatic line (DL5, 106).

23. Compressed air generating device (2.5, 2.6), comprising at least one electric motor (24), two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, an air inlet (8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), an intercooler (20) and an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), an air dryer (40) whose inlet is connected to the outlet of the aftercooler (22), and a coolant inlet opening (12) through which coolant is supplied to the intercooler (20) and the aftercooler. (22) a liquid coolant can be supplied, with a coolant outlet opening (14),through which heated coolant can be discharged, with a multi-circuit protection valve (50) which pneumatically connects the outlet of the air dryer (40) to at least one external compressed air reservoir (45) and external compressed air consumers (51, 52), and with a control and regulating device (28) which is connected to the multi-circuit protection valve (50) and sensors arranged therein via at least one sensor line (56), characterized in that the multi-circuit protection valve (50) can be separated from the other components of the compressed air generation device and can be operated remotely from these components, that the control and regulating device (28) and the multi-circuit protection valve, (50) have electrical connecting means (64, 68) which are detachably connected to each other via the at least one flexible electrical sensor line (56), and that the multi-circuit protection valve (50) has pneumatic connecting means (62) which are detachably connected at least indirectly to the outlet of the air dryer (40) via at least one flexible pneumatic line (DL5, 106).

24. Compressed air generating device (2.6) according to claim 22 or 23, characterized in that a dryer module (94) comprising the air dryer (40) has at least one electrical connector socket (100) and at least one pneumatic connector socket (104), that the electrical connector socket (100) of the dryer module (94) is connected to an electrical connector socket (68) on the control and regulating device (28) via the sensor line (56), that an electrical plug of an electrical connecting line (102) can be detachably inserted into the electrical connector socket (100) of the dryer module (94), that this electrical connecting line (102) has a second plug which can be detachably inserted into an electrical connector socket (64) of the multi-circuit protection valve (50), that the pneumatic connector socket (104) of the dryer module (94) is pneumatically connected to the fifth compressed air line (DL5),through which dried compressed air coming from the air dryer (40) can be directed, that a plug of a pneumatic connecting line (106) can be detachably inserted into this pneumatic plug socket (104) of the dryer module (94), and that the pneumatic connecting line (106) has a second plug which can be detachably inserted into a pneumatic plug socket (62) of the multi-circuit protection valve (50).

25. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9), with a control and regulating device (28), with at least one electric motor (24), with at least one air compressor (16, 18) driven by the electric motor (24), with an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the air compressor (16, 18), with at least one air cooler (20, 22) in which the air compressed by the air compressor (16, 18) can be cooled, with an air dryer (40) with which compressed air can be dried, with a coolant inlet opening (12) through which a liquid coolant can be supplied to the air cooler (20, 22), and with a coolant outlet opening- nung (14), through which heated coolant can be discharged, characterized in that the control and regulating device (28) is an integral part of the inverter (26).

26. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9), with at least one electric motor (24), with two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, with an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), with an intercooler (20) and an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), and with an air dryer (40), the inlet of which is connected to the outlet of the aftercooler ( 22) is connected, as well as with a coolant inlet opening (12) through which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22),with a coolant outlet opening (14) through which heated coolant can be discharged, with a multi-circuit protection valve (50) which pneumatically connects the outlet of the air dryer (40) to at least one external compressed air reservoir (45) and to external compressed air consumers (51, 52), and with a control and regulating device (28) which is connected to the multi-circuit protection valve (50) and to sensors arranged therein via at least one sensor line (56), characterized in that the control and regulating device (28) is an integral part of the inverter (26).

27. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9), with at least one electric motor (24), with two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, with an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), with an intercooler (20) and an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), and with an air dryer (40) whose inlet is connected to the outlet of the aftercooler (22), as well as with a coolant inlet opening (12) through which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), and with a coolant outlet opening (14) through which heated coolant can be discharged, with a multi-circuit protection valve (50) which pneumatically connects the outlet of the air dryer (40) to at least one external compressed air reservoir (45) and external compressed air consumers (51, 52), and with a control and regulating device (28) which is connected to the multi-circuit protection valve (50) and sensors arranged therein via at least one sensor line (56), characterized in that the control and regulating device (28) is an integral part of the multi-circuit protection valve (50).

28. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9), comprising a control and regulating device (28), at least one electric motor (24), two air compressors (16, 18) driven by the electric motor (24) and acting sequentially, an air inlet (8, 8*) through which ambient air (L) can be drawn in by means of the first air compressor (16), an intercooler (20) and an aftercooler (22), wherein the inlet of the intercooler (20) is pneumatically connected to the outlet of the first air compressor (16), wherein the outlet of the intercooler (20) is pneumatically connected to the inlet of the second air compressor (18), and wherein the outlet of the second air compressor (18) is pneumatically connected to the inlet of the aftercooler (22), and an air dryer (40), whose inlet is connected to the outlet of the aftercooler (22), as well as to a coolant inlet opening (12),via which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), and with a coolant outlet opening (14) via which heated coolant can be discharged, with a multi-circuit protection valve (50) which pneumatically connects the outlet of the air dryer (40) to at least one external compressed air reservoir (45) and external compressed air consumers (51, 52), and with a control and regulating device (28) which is connected via at least one sensor line (56) to the multi-circuit protection valve (50) and sensors arranged therein, characterized in that the control and regulating device (28) is an integral component of a central vehicle control unit (110).

29. Method for operating a compressed air generation device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9) with the features of at least one of the device claims, wherein compressed air by means of the at least one air compressor (16, 18) is cooled in at least one air cooler (20, 22), wherein this cooled compressed air is supplied to an air dryer (40) and dried there, wherein the dried compressed air is supplied to compressed air consumers (51, 52) and / or at least one compressed air storage tank (45), and wherein, for the purpose of regenerating a desiccant (41) arranged in the air dryer (40), dry compressed air in the volume of a regeneration compressed air volume is passed through it and subsequently discharged into the environment, characterized in that the regeneration compressed air volume necessary for the regeneration of the desiccant (41) is calculated at least as a function of the temperature,which has the coolant before and / or after flowing through the air cooler (22) which is arranged as the last air cooler (22) before the air dryer (40), and that the regeneration compressed air volume determined in this way is then passed through the air dryer (40).

30. Method according to claim 29, characterized in that the coolant temperature is measured by means of a first temperature sensor (73) in front of the coolant inlet opening (12) of the compressed air generating device (2), and that the regeneration compressed air volume required for drying the desiccant (41) in the air dryer (40) is controlled and / or regulated through the air dryer (40) as a function of the measured coolant temperature during a subsequent regeneration process.

31. Method according to claim 29, characterized in that the coolant temperature is measured by means of a second temperature sensor (73') immediately before the coolant inlet of the air cooler (22) which is arranged as the last air cooler before the air dryer (40) in the direction of flow of the compressed air, and that the regeneration compressed air volume required for drying the desiccant (41) in the air dryer (40) is controlled and / or regulated through the air dryer (40) depending on the measured coolant temperature during a subsequent regeneration process.

32. Method according to claim 29, characterized in that the coolant temperature is measured by means of a third temperature sensor (73") downstream of the coolant outlet of the air cooler (22) which is arranged as the last air cooler upstream of the air dryer (40) in the direction of flow of the compressed air, and that the regeneration compressed air volume required for drying the desiccant (41) in the air dryer (40) is controlled and / or regulated through the air dryer (40) depending on the measured coolant temperature during a subsequent regeneration process.

33. Method for operating a compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9) with the features of at least one of the device claims and with the features of at least one of the method claims 29 to 32, characterized by the following method steps: a) drawing in ambient air by means of the first air compressor (16), b) pre-compressing the drawn-in ambient air in the first air compressor (16) to a first air pressure value, c) cooling an intercooler (20) with a liquid coolant, d) cooling the pre-compressed compressed air in the intercooler (20), e) further compressing the compressed air to a second, higher pressure value by means of a second air compressor (18), f) cooling an aftercooler (22) with the liquid coolant, wherein the aftercooler (22), viewed in the direction of flow of the coolant, is considered the first air cooler by the coolant is achieved hydraulically,g) Cooling the compressed air, which is further compressed in the second air compressor (18), in the aftercooler (22), h) Drying the cooled compressed air in an air dryer (40), i) Forwarding the cooled and dried compressed air to compressed air consumers (51, 52) and / or to at least one compressed air storage tank (45), j) Forwarding the liquid coolant from the aftercooler (22) to the intercooler (20), k) Forwarding the liquid coolant from the intercooler (20) to a cooling device (25) of the electric motor (24), l) Forwarding the liquid coolant from the cooling device (25) of the electric motor, tors (24) to a cooling device (48) of the second air compressor (18), m) Transferring the liquid coolant from the cooling device (48) of the second air compressor (18) to a cooling device (27) of the inverter (26), n) Transferring the liquid coolant from the cooling device (27) of the inverter (26) to a cooling device (46) of the first air compressor (18), o) Transferring the liquid coolant from the cooling device (46) of the first air compressor (18) to an external cooling device (82).

34. Method according to one of claims 29 to 33, characterized in that the time interval between two regeneration processes for drying the desiccant (41) of the air dryer (40) is controlled and / or regulated depending on the temperature of the coolant which the coolant has at the outlet of the external cooling device (82) or at the inlet of the aftercooler (22).

35. Method according to one of claims 29 to 34, characterized in that the time interval between two regeneration processes for drying the desiccant (41) of the air dryer (40) is controlled and / or regulated depending on the average ambient temperature during a subsequent regeneration process.

36. Method according to one of claims 29 to 34, characterized in that the regeneration compressed air volume required for drying the desiccant (41) is controlled and / or regulated as a function of the ambient temperature during a subsequent regeneration process.

37. Method according to one of claims 29 to 36, characterized in that the regeneration compressed air volume required for drying the desiccant (41) or the duration and / or frequency of the regeneration processes is controlled and / or regulated as a function of the difference between the ambient temperature and the coolant temperature.

38. Method according to one of claims 29 to 37, characterized in that in the case of an unregulated control of the regeneration of the desiccant (41) of the The air dryer (40) determines the maximum high temperature value of the coolant expected during the operation of the compressed air generation device (2.3, 2.4, 2.5, 26, 2.7), that this value of the coolant temperature serves as the basis for determining a maximum regeneration compressed air volume, and that a corresponding regeneration process for the desiccant (41) is carried out with this maximum regeneration compressed air volume.

39. Method according to one of claims 29 to 38, characterized in that the coolant from the coolant outlet of the intercooler (20) is not conveyed directly, but via a dryer module cooler (40.1 ) to the coolant inlet of the electric motor (24), and that the dryer module cooler (40.1 ) cools at least components of the air dryer (40).

40. Method according to one of claims 29 to 38, characterized in that the temperature of the coolant is measured at the outlet of the first external cooling device (82) or at the inlet of the aftercooler (22), and that when the determined temperature of the coolant reaches or exceeds a previously defined high limit, the transport of compressed air from the outlet of the first air compressor (16) no longer takes place via the intercooler (20) but via the second external cooling device (120) to the inlet of the second air compressor (18).

41. Method according to one of claims 29 to 38, characterized in that the temperature of the coolant is measured at the outlet of the first external cooling device or at the inlet of the aftercooler (22), and that when the temperature of the coolant reaches or exceeds a previously defined second limit value which is greater than the first limit value, the transport of compressed air from the outlet of the first air compressor (16) no longer takes place via the intercooler (20) but via the second external cooling device (120) to the inlet of the second air compressor (18), and that then additionally the transport of compressed air from the outlet of the second air compressor (18) is no longer directed via the aftercooler (22) but via the third external cooling device (122) to the outlet of the aftercooler (22) or to the inlet of the air dryer (40).

42. Method according to one of claims 29 to 38, characterized in that even when no compressed air is passed through the intercooler (20) and / or the aftercooler (22), the liquid coolant of the first external cooling device (82) is passed through the cooling devices (25, 27, 46, 48) of the electric motor (24), the inverter (26) and the two air compressors (16, 18).

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