Compressed-air supply unit, compressed-air supply system, vehicle and operating method

A compressed-air supply system for a sensor cleaning device of a vehicle, the compressed-air supply system comprising:

• a compressed-air supply unit having a compressed-air port;
• a compressed-air generator for supplying compressed air at said compressed-air port;
• said compressed-air supply unit being connected to said compressed-air generator via said compressed-air port, said compressed-air supply unit being for supplying compressed air for the sensor cleaning device;
• said compressed-air supply unit further having a compressed-air supply port for connecting the sensor cleaning device and a pneumatic main line for conducting the compressed air from said compressed-air port to said compressed-air supply port in a filling direction;
• said compressed-air supply unit including an air dryer arranged in said pneumatic main line for drying the compressed air conducted in the filling direction;
• said compressed-air supply unit further including a throttle associated with said air dryer and a water separator arranged in said pneumatic main line between said compressed-air port and said air dryer;
• said compressed-air supply unit further including a branch line departing from said pneumatic main line between said water separator and said air dryer and reconnecting between said air dryer and said compressed-air supply port;
• said branch line having a pneumatic branch-line switching valve configured, in a first operating mode, to open said branch line in a direction of said compressed-air supply port so that air can flow through said branch line pneumatically;
• and,
• said compressed-air supply unit being configured, in said first operating mode, to allow return of the compressed air from said branch line through said throttle counter to the filling direction.

A vehicle comprising:

• a compressed-air consumer connected to a compressed-air supply port;
• a compressed-air supply system for providing compressed air at said compressed-air supply port;
• said compressed-air supply system including a compressed-air supply unit having a compressed-air port and a compressed-air generator for supplying the compressed air at said compressed-air port;
• said compressed-air supply unit being connected to said compressed-air generator via said compressed-air port, said compressed-air supply unit being for supplying the compressed air for the compressed-air consumer;
• said compressed-air supply unit further having a compressed-air supply port for connecting the compressed-air consumer and a pneumatic main line for conducting the compressed air from said compressed-air port to said compressed-air supply port in a filling direction;
• said compressed-air supply unit including an air dryer arranged in said pneumatic main line for drying the compressed air conducted in the filling direction;
• said compressed-air supply unit further including a throttle associated with said air dryer and a water separator arranged in said pneumatic main line between said compressed-air port and said air dryer;
• said compressed-air supply unit further including a branch line departing from said pneumatic main line between said water separator and said air dryer and reconnecting between said air dryer and said compressed-air supply port;
• said branch line having a pneumatic branch-line switching valve configured, in a first operating mode, to open said branch line in a direction of said compressed-air supply port so that air can flow through said branch line pneumatically;
• said compressed-air supply unit being configured, in said first operating mode, to allow return of the compressed air from said branch line through said throttle counter to the filling direction;
• an electronic control unit for controlling said compressed-air supply system;
• and,
• wherein said electronic control unit is connected by control technology at least to said pneumatic branch-line switching valve.

A method for operating a compressed-air supply system, the method comprising:

• supplying compressed air at a compressed-air port which is connected to a compressed-air supply port via a pneumatic main line;
• separating condensate from moist compressed air, supplied at the compressed-air port, for supplying dehumidified compressed air;
• drying the dehumidified compressed air conducted to the compressed-air supply port in a filling direction with an air dryer arranged in the pneumatic main line in a basic operating mode;
• supplying the compressed air from the pneumatic main line at the compressed-air supply port in the basic operating mode;
• opening a branch line so that air can flow through the branch line pneumatically in a direction of the compressed-air supply port, via a pneumatic branch-line switching valve in a first operating mode;
• and,
• returning the dehumidified compressed air from the branch line through the pneumatic main line counter to the filling direction in the first operating mode.