An exploratory investigation is proposed which seeks to establish the technical feasibility of a novel instrumentation approach for the continuous measurement of particle density in the exhaust of a compression ignition engine. The proposed instrument is required to satisfy the critical sensing function of a certain full-authority fuel injection and engine control system now under development for very-high-altitude, subsonic, unmanned aircraft propulsion. The proposed instrument is comprised of a single, self-contained, rugged unit that can be mounted remotely from the engine to provide a robust indication of the concentration of exhaust particulate matter. Such a system facilitates a facultative compression ignition engine that is capable of effectively utilizing highly variable amounts of air with a combination of two cylinder-injected fuels under computer control, one fuel of high energy content, the other highly oxygenated. By such means, fuel consumption can be minimized during the protracted climb phase anticipated for very high altitude vehicles thereby allowing greater cruise / loiter fuel reserves. The proposed investigation combines analytical studies with breadboard instrument testing to establish feasibility for the intended application. Correlations with established photopic and particulate methods will also be undertaken.Commercial Applications:A highly portable and easily operated "smokemeter" has wide-spread commercial potential. All diesel engines are prone to emit excessive particulate matter under prominent operating conditions. Virtually all such engines now manufactured are sold and operated subject to compliance with stringent state and federal particulate emission criteria. However, the emission regulations are not yet fully effective because there are no completely satisfactorily and valid particulate instruments available for field use. The proposed instrumentation technology offers such prospects.
