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Collection of diesel exhaust using the Tapered Element Oscillating Microbalance (TEOM) instrument was investigated as an alternative to the traditional method of filter weighing for particulate matter mass determination. Such an approach, if successful, would eliminate considerable manual labor involved in weighing, as well as the delay of hours or days before final results were known. To avoid known artifacts in the second-by-second mode of operation, the TEOM was used in a phase-by-phase mode and was equilibrated with air of constant temperature and humidity before each measurement. Electrically operated valves were used to automate the equilibration and measurement process. The study also included a comparison between two types of TEOM filter - an older type and a new one designed by the TEOM manufacturer for more uniform flow and less flexing. Best results were obtained with the TEOM using the new filter under no-flow conditions.

A high-speed/high-resolution imaging technique and analysis were applied to study fuel injector spray timed evolution in ambient air and in a motored single-cylinder engine. Alcohol fuel was injected from a mid-pressure injection system into the engine cylinder at shaft speed of 1,000 rpm. The fuel injection system with various nozzles was designed for use in the EPA/NVFEL program to develop clean and efficient engines that use alternative fuels. A 15W copper vapor laser with a fiber optic delivery system synchronized with a high-speed drum streak camera was utilized to expose films at 5,000 frames per second (fps). The spray characteristics were investigated at 15.0 MPa injection pressure and injection duration range of 3-5 ms. A sequence of successive frames was selected from the films to examine the influence of the injector parameters and the valve lift on the atomization process. The spray penetration was quantified by analyzing the high-speed films.