Device for regulating the pressure of a fluid supplied to an internal combustion engine from a fluid pressure source

In combination with an internal combustion engine and a source of fluid pressure connected to the internal combustion engine via an air intake line, a system for regulating fluid pressure in the air intake line, the system including a bypass conduit opening to the atmosphere, the system comprising:

• a valve having a valve stem and disposed for connecting the air intake line to the bypass conduit, a downstream port in the intake line downstream of the source of fluid pressure, a pressure controller connected to both the valve and the valve stem, the pressure controller including a housing and a pair of movable walls therein defining a chamber therebetween with first and second spring means for biasing the respective movable walls toward one another so as to vary the volume of the pressure chamber formed therebetween, means for connecting the valve stem to one of said movable walls wherein the valve is biased to the closed position by the first spring means, means for connecting the downstream port to a first calibrated aperture in the fluid pressure chamber wherein as the pressure in the air intake rises so does the pressure in the pressure chamber, an additional calibrated aperture carried by the other movable wall, the additional calibrated aperture forming a passageway which is movable between a first position wherein the aperture is open to the atmosphere and a second position wherein the aperture is blocked, the aperture being biased toward the first position by said second spring means, whereby when the pressure in the air intake increases to a level sufficient to overcome the bias of the spring means the second aperture is closed allowing the pressure in the fluid pressure chamber to open the valve and relieve pressure in the air intake of the engine.