Air bleed control for carburetor idle system

Claim 1

In a carburetor for an internal combustion engine having a fuel bowl, an air and fuel mixture conduit, a throttle valve mounted within said conduit, an idle port in the mixture conduit adjacent the closed position of the throttle valve, an idle fuel passage between the idle port and the fuel bowl, an air bleed port in said carburetor in fluid communication with the idle fuel passage, and an air bleed valve member to control the amount of air flow through said air bleed port, the improvement of air bleed valve control means integral with said carburetor to control the movement of said valve member, said control means comprising a body having an air chamber therein, a diaphragm in said body having one side thereof facing the air chamber, a vacuum chamber adjacent the other side of said diaphragm in fluid communication with an intake manifold of the internal combustion engine, a check valve member between the vacuum chamber and the air chamber and having a restricted opening of a predetermined size to permit fluid communication between the vacuum and air chambers in a seated position of the check valve member, spring means urging the diaphragm in a direction toward the said air chamber, an operating stem operatively connected between the air bleed valve member and diaphragm and positioned within the vacuum chamber to move with the diaphragm, said diaphragm being responsive to manifold vacuum and upon rapid engine deceleration said diaphragm and operating stem in response to the relatively large pressure differential between the said vacuum chamber and the said air chamber to move said air bleed valve member in one direction to provide maximum air flow to said idle fuel passage, said pressure differential being reduced upon the flow of air through the restricted opening in said check valve member whereby after a predetermined time said air bleed valve member moves in an opposite direction to reduce the air flow to said idle fuel passage.