Patent ID: 8801111

Claim:
A vehicle air braking system comprising: a source of fluid under pressure, an air dryer downstream of said source, an air consumer circuit downstream of the air dryer, control means to suspend the source on demand to permit backflow of air under pressure from the air consumer circuit through the air dryer to a drain valve, the control means comprising a regeneration valve, a command valve comprising an inlet connected to the air consumer circuit, a supply outlet operably connected to the drain valve, a compressor unloader the source being suspendable via said compressor unloader, the compressor unloader being operable via an unloader valve, said unloader valve comprising an inlet connected to the air consumer circuit and an outlet connected to the compressor unloader, and an electrical actuator operably connected to the unloader valve, wherein the regeneration valve is operable to permit regeneration backflow in response to connection of the inlet and supply outlets of the command valve, wherein the regeneration valve is connected to the command valve by a pilot pressure line, wherein the regeneration valve is openable in response to connection of the inlet and supply outlets of the command valve, and wherein the system is configured so that when an unloader signal is generated by electrical actuation of the unloader valve, the drain valve remains closed, and air under pressure between the source of fluid under pressure and the air dryer is not exhausted.