Twin chamber air dryer and pneumatic system

A twin chamber air dryer for a pneumatic system of a commercial vehicle, said twin chamber air dryer comprising:

• a supply inlet port to be connected to a compressor, a supply outlet for supplying dried compressed air to a pneumatic consumer system, a compressor control outlet for delivering a pneumatic unloader signal, an exhaust outlet,
• a first desiccant cartridge and a second desiccant cartridge, to be operated alternately,
• a toggling valve assembly for switching between said first desiccant cartridge and said second desiccant cartridge,
• a pneumatically controlled purge valve switchable between a blocking basic position and an activated position for connecting said supply inlet port to said exhaust outlet, and
• a solenoid valve assembly, said solenoid valve assembly comprising:
• a directional control solenoid valve for receiving an electrical direction control signal and controlling said toggling valve assembly,
• a regeneration solenoid valve for receiving an electrical regeneration control signal and providing pressurized air in regeneration phases of said first and second desiccant cartridges, and
• a governor solenoid valve for receiving an electrical governor control signal, controlling said purge valve, and outputting said pneumatic unloader signal,
• wherein each of said direction control solenoid valve, said regeneration solenoid valve, and said governor solenoid valve can be operated independently by said electrical direction control signal, said electrical regeneration control signal, and said electrical governor control signal.