Dual fuel feed system carburetor

Abstract

A carburetor dual fuel feed system has a primary passage for flowing fuel into a venturi of a fuel-and-air mixing passage, and a supplemental channel flowing fuel into a mixing passage upstream region. Sizing of the primary passage and channel with respect to pressure dynamics of each region disassociates low from high power engine fuel calibration. This disassociation ultimately achieves a leaner fuel-and-air mixture flow during low power conditions which reduces carbon monoxide emissions, and achieves a richer mixture flow during high engine power conditions which reduces NOx emissions. During low engine power conditions, substantially all of the fuel which mixes with clean air flowing through the venturi of the mixing passage flows from the primary passage. During high engine power conditions, supplemental fuel flow into the mixing passage is induced by a vacuum created about a nozzle of the channel.