Technical Paper
“A Study of Factors Affecting Carburetor Performance at Low Air Flows”
1969-02-01
690137
Carburetor repeatability at idle was investigated both on the carburetor precision flow stand and on a chassis dynamometer equipped with exhaust emission test equipment. It was determined that some factors which significantly affect idle fuel flow repeatability on the carburetor test stand are: 1 Surface roughness of mating parts in the fuel bowl inlet system. 2 Inlet valve eccentricity. 3 Hydraulic shock in the fuel supply circuit. In addition, vehicle testing had demonstrated that carbon monoxide changes at idle may occur with constant fuel-air ratio due to changes in fuel temperature. Cycle tests have also shown a relationship between fuel temperature and carbon monoxide levels.