Understand the functional difference between a ‘Choke Valve Assembly’ and a ‘Throttle Valve Assembly’.
Answer: For example, a chokevalve assembly for the air intake passage of an internal combustion engine employs a shaft mounted off-center with respect to the passage, an actuator connected to turn the shaft in a direction to close the choke valve, a vacuum operated device for turning the shaft in a direction to open the choke valve when the engine starts, and a limiter member connected to limit the extent of opening movement of the choke valve in accordance with the position of the actuator. A spring is operatively interposed between the actuator and the choke valve so that the force of the spring increases as the actuator is moved beyond the position corresponding to the closed position of the choke valve. A cam track on the actuator is engaged by a follower on the limiter member. In a throttle valve assembly, for example, fora carburetor having a carburetor body with an intake passage therein; a slidable throttle valve guide tube connected to said carburetor body and guidably supporting said slidable throttle valve, said carburetor body having guide grooves for guiding said slidable throttle valve, said guide grooves being respectively provided in said body at opposite sides of said intake passage so as to be continuous with said throttle valve guide tube, the improvement wherein said throttle valve and said guide grooves are so shaped that said throttle valve and said guide grooves come into contact with each other respectively along lines extending in the sliding direction of said slidable throttle valve at downstream portions of said throttle valve, said throttle valve and guide grooves having a slight difference in curvature of respective surfaces adjacent their lines of contact during operation.