Analysis and Digital Simulation of Carburetor Metering

This paper reports a comprehensive analysis of carburetor metering, employing the fundamentals of fluid mechanics, thermodynamics, and numerical analysis, to develop a simulation program. This includes the interactions between individual systems as well as the relationships of the fuel, ambient air, engine, and vehicle variables to carburetor metering. Mathematical models for the individual systems of an air-bled, double-venturi carburetor are established, and a logical iteration procedure is developed to solve the resulting simultaneous relationships utilizing a digital computer. Basic data on air-bleed flow rates, pressure losses for two-phase flow, and fuel-property effects, are presented and discussed. Applications of the simulation are illustrated, and experimental data from both on-engine carburetor tests and fuel-channel model tests are utilized to evaluate the predictions.