Charge forming device

Claim 1

A charge forming device for an internal combustion engine including an induction passage, a choke valve in the passage, a temperature responsive element operatively connected to the choke valve and adapted to urge the valve to a closed position with a force inversely proportioned to the engine temperature, a vacuum responsive device operatively connected to the choke valve and adapted to move the same from a closed position to a variable partially open position at a controlled rate in response to a predetermined vacuum in the engine intake manifold obtained when the engine is operating above cranking speed, said vacuum responsive device including a casing, a flexible diaphragm dividing the casing into two main chambers, resilient means urging the diaphragm and operatively connected choke valve to a closed position, a rigid wall assembly separating one of the main chambers into first and second subchambers, at least one aperture in said rigid wall assembly, a valve member normally engaging said rigid assembly and closing said aperture against air flow from the first subchamber, bypass means permitting restricted fluid flow in either direction between said subchambers, a vacuum passage adapted to connect said second subchamber with a source subject to engine intake manifold vacuum, adjusting means for limiting the extent of movement of the diaphragm and coincident opening of the choke valve, said valve member being axially offset from the axial center of the device and said adjusting means comprising a stop member extending through said rigid wall into said one subchamber, said stop member also being axially offset from the axial center of the device on the opposite side from the flexible valve member.