Automatic choke valve apparatus in an internal combustion engine

Claim 1

An automatic choke valve apparatus for an internal combustion engine comprising a choke valve mounted in an intake passage of an internal combustion engine, an operation shaft connected to said choke valve, an external pulse motor including a drive shaft, an intermediate torsion spring connecting said operation shaft and said drive shaft, coupling means between said shafts for imparting drive from said drive shaft to said operation shaft only in regular direction of rotation of the drive shaft, and a driving pulse circuit means connected to said pulse motor for driving the same from a position for engine starting to a position when engine firing is completed, said driving pulse circuit means comprising an electrical circuit having a first input sensitive to closure of an ignition switch, a second input sensitive to the beginning of completed engine firing, variable resistor means sensitive to engine temperature, and control means coupled to said inputs and resistor means for producing pulses for driving said pulse motor to move the choke valve in one direction from the engine starting position to the position at which completed engine firing is obtained, said pulses being produced by said circuit at a frequency and for a time period in accordance with the variable resistance of the resistor means whereby the choke valve is driven at a rate of speed and for a time interval related to engine temperature.