Air/fuel ratio control system for gaseous fueled engines

Abstract

The invention provides a system that controls the air intake pressure of a venturi mixer in an air/fuel ratio control system for gaseous fueled engines to match the fuel vaporizer/regulator output pressure (negative pressure) or to a desired set point of a fuel vaporizer/regulator connected to the fuel inlet of the venturi mixer. A differential pressure control valve in the air intake upstream of the venturi is used, which results in negative pressure vaporizer/regulators being compatible with the constant air/fuel ratio fluidic control principle of the venturi mixer. A differential pressure sensor or estimated differential pressure based on airflow and valve position is used in one embodiment to control the venturi intake air pressure to the desired set point. The set point may be zero or biased by an outer control loop of an engine controller.

Dependencies are inferred from the claim text.