An Optical Sensor for Measuring Fuel Film Dynamics of a Port-Injected Engine

Increasingly stringent emissions regulations and customer demands for high efficiency and smooth performance demand highly accurate control of the air-fuel ratio of automotive spark-ignition engines. Electronic port fuel injection provides the necessary control by adding a precise quantity of fuel for a given amount of air drawn in by the engine. Ideally, the metered fuel will consist only of fine droplets and vapor. In reality, the fuel spray impinges upon the walls of the intake port, creating a liquid fuel film. The fundamentally different transport mechanisms of the liquid fuel compared to vapor or fine droplets greatly complicates; the analysis of the fuel delivery system. Past research has provided models of fuel film dynamics in intake ports of port-fuel-injected engines, yet to date no practical method of measuring fuel films has been presented. This research attempts to fill this gap with the design and development of a method of measuring port wall wetting in production, port-fuel-injected engines. This work describes the design and installation of multiple optical sensors [1] flush in the engine's intake port and engine test results for two of the installed sensors.