Analysis and Experiments on Carburetor Metering at the Transition Region to the Main System

A series of analyses and experiments has been carried out on the problem of poor air/fuel ratio characteristics at the transition region from the idle system to the main system. The fuel supply characteristic of the idle system, as well as that of the main system, has been treated as a function of intake air-flow rate.

It has been shown theoretically that the behavior of the fuel in the transition region results from the fuel passage construction of the conventional type of carburetor, and that a uniform air/fuel ratio can never be supplied in the transition region without a main air-bleed system. The effects of the main air-bleed system on fuel supply characteristics at the transition region have been investigated quantitatively. The mechanism of fuel supply at the transition region has been confirmed through experiments made on actual parts.