Automatic choke apparatus and method

An automatic choke apparatus for use in starting an internal combustion engine comprising:

• a carburetor having an air inlet, a fuel inlet, and an air and fuel mixture outlet;
• a choke plate mounted for variable rotation in an interior of the carburetor adjacent the air inlet between a closed position wherein a flow of air entering the carburetor through the inlet is substantially obstructed and an open position wherein the flow of air entering the carburetor is substantially unobstructed, the choke plate being rotatable toward the open position after starting, the choke plate having a choke shaft arm rotatably moving the choke plate;
• and
• a throttle plate downstream from the choke plate and the fuel inlet mounted for variable rotation in the interior of the carburetor between an open position wherein a flow of mixed air and fuel exiting the carburetor through the outlet is at a maximum and a closed position wherein the flow of mixed air and fuel exiting the carburetor is at a minimum, the throttle plate being rotatable toward the closed position after starting, the throttle plate having a throttle lever rotatably moving the throttle plate, the throttle lever being engageable with the choke shaft arm during rotational movement of the throttle plate to rotatably move the choke plate.

An internal combustion engine having an automatic choke comprising:

• a carburetor including:
• a choke plate having a choke shaft, the choke plate mounted in an interior of the carburetor for variable rotation about an axis defined by the choke shaft, and a choke shaft arm connected to the choke shaft and rotatably moving the choke shaft and choke plate;
• means for supplying air to the carburetor;
• means for supplying fuel to the carburetor to be mixed with the air in the carburetor;
• a throttle plate having a throttle shaft, the throttle plate positioned in the interior of the carburetor downstream of the choke plate and the means for supplying fuel and mounted for variable rotation about an axis defined by the throttle shaft, and a throttle lever connected to the throttle shaft and rotatably moving the throttle shaft and throttle plate, the throttle lever being engageable with the choke shaft arm as the throttle lever rotatably moves the throttle plate;
• and
• means for supplying a mixture of fuel and air from the carburetor to a combustion means;
• temperature responsive means for positioning the choke plate in an open position as the engine temperature sensed increases;
• the temperature responsive means positioning the choke plate in a closed position as engine temperature sensed decreases;
• combustion means for converting the air and fuel mixture to rotational movement of an engine output shaft;
• an engine output shaft;
• and
• governor means for moving the throttle lever for positioning the throttle plate to limit the maximum rotational speed of the engine output shaft, the governor means urging the throttle plate from an open position toward a closed position after the engine is started such that the throttle lever rotatably moves the choke shaft arm which rotatably moves choke plate toward the open position before the temperature responsive means activates to sufficiently open the choke plate.