Effects of Air-Bleed Systems on Carburettor Performance

Abstract

This paper is concerned with a survey on the effect of air-bleed systems on the fuel-air ratio of the mixture which is made by a carburettor having a main system only. Calculations and experiments were made to investigate the influences of the location of the air-bleed hole relative to the fuel level in the float chamber, and diameters of air jet and nozzle upon the mixture strength. The results calculated using the equations have been found in good qualitative agreement with these obtained from the experiments. The following are noteworthy results : (1) The location of the air-bleed hole affects the mixture strength in a range of the smaller air flow through the venturi. (2) The diameter of the air jet affects the mixture strength in a range of the larger air flow through the venturi. (3) The increase of the nozzle diameter weakens these effects.