Carburetor throttle valve positioner

Claim 1

A carburetor throttle valve positioner comprising, in combination, an engine carburetor having an induction passage open to atmospheric pressure at one end and adapted to be connected to an engine intake manifold at the opposite end so as to be subject to engine vacuum varying in level from ambient atmospheric pressure at engine shutdown to a maximum subatmospheric pressure level during engine deceleration operating conditions, a throttle valve rotatably mounted across said passage and movable from a first position essentially closing the induction passage to an engine idle speed position and beyond to a wide open throttle position, and return, for controlling flow through said passage, the carburetor including an idle fuel/air mixture passage connected to the induction passage around the throttle valve and having transfer port means straddling at times the edge of the throttle valve and having a discharge end connected to the induction passage below the first closed throttle position so as to always provide an idle air/fuel mixture so long as the engine is running regardless of the position of the throttle valve whereby the idle passage is subjected to the engine to a manifold vacuum signal at one level when the throttle is at its idle speed position and a lower level vacuum signal when the throttle valve is in the first closed position and control means to move said throttle valve to said positions, said control means including first means operatively biasing said throttle valve to an open throttle position, and power means responsive to engine shutdown operation for effecting initially a movement of said throttle valve to its first closed throtle position to reduce the flow of a fuel/air mixture through said passage, and subsequently a movement of said throttle valve to an open position for an engine starting operation.