Vacuum controlled 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 eengine deceleration operating conditions, a throttle valve rotatably mounted across the passage and movable from a closed position to an engine idle speed position and beyond to a wide open throttle position, and return, for controlling flow through the passage, an idle fuel/air mixture passage connected to the induction passage around the throttle valve and having a discharge end connected to the induction passage at a location above the closed throttle valve position but adapted to be traversed by the throttle valve as it moves towards an open position so that the idle passage is subjected to manifold vacuum when the throttle valve is positioned beyond the closed position to provide normal idle and beyond normal idle speed mixture flow and subjected to ambient pressure level during closed throttle valve position to terminate idle mixture flow, and control means to move the throttle valve to and between its positions, the control means comprising power means having a first plunger operatively adapted to engage or be engaged by the throttle valve for moving the same or restricting the movement thereof, respectively, spring means acting on and biasing the first plunger to a first position urging the throttle valve to an open beyond engine idle speed position conditioning the engine for a hot start leaner fuel/air ratio, first engine intake manifold vacuum responsive servo means operatively acting on the first plunger in opposition to the spring means whereby the first plunger is retracted to an engine anti-dieseling second position permittIng rotation of the throttle valve to a throttle valve closed position terminating flow of fuel/air to the engine, and second plunger means movable in the path of movement in a throttle valve closing direction of the first plunger to alternately prevent movement of the first plunger beyond a third position permitting rotation of the throttle valve to a curb idle normal engine idle speed position providing a richer fuel/air ratio, or permit movement of the first plunger to the antidieseling second position, and second intake manifold vacuum responsive means for controlling movement of the second plunger to its various positions.