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The focus of this work was the physical characterization of exhaust aerosol from the University of Minnesota Formula SAE team's engine. This was done using two competition fuels, 100 octane race fuel and E85. Three engine conditions were evaluated: 6000 RPM 75% throttle, 8000 RPM 50% throttle, and 8000 RPM 100% throttle. Dilute emissions were characterized using a Scanning Mobility Particle Sizer (SMPS) and a Condensation Particle Counter (CPC). E85 fuel produced more power and had lower particulate matter emissions at all test conditions, but more fuel was consumed.

A one-stage dilution tunnel has been developed to sample and dilute diesel exhaust. The tunnel has the capability of simulating many aspects of the atmospheric dilution process. The dilution rate and overall dilution ratio, temperature, relative humidity, and residence time in the tunnel, as well as residence time and temperature in the transfer line between the tunnel and exhaust sampling point may be varied. In this work we studied the influence of the exhaust transfer line, tunnel residence time, and dilution air temperature on the exhaust particle size distribution. The influences of fuel sulfur content on the size distribution and on the sensitivity of the size distribution to dilution and sampling conditions were also examined. We do not suggest an optimum dilution scheme, but do identify critical variables.

This paper quantifies typical United States in-vehicle cowl area particulate filter parameters such as temperature, humidity and environmental conditions. Secondly, United States and Germany particulate filter fleet results will be included to help quantify the effect of loading on electret nonwoven particulate filter fractional efficiency and demonstrate the amount and types of particulate matter captured. Finally the paper will address the low submicron fractional filter efficiency of a simulated production “wet and dry” plate-fin automotive evaporator core.

Particle size distribution and number concentration measurements have been made in the diluted exhaust of a medium-duty, turbocharged, aftercooled, direct-injection Diesel engine using a unique variable residence time micro-dilution system that allows systematic variation of dilution and sampling conditions, and a scanning mobility particle sizer (SMPS). The measurements show that the number concentrations in the nanoparticle (Dp < 50 nm) and the ultrafine (Dp < 100 nm) ranges are very sensitive to dilution conditions and fuel sulfur content. Changes in concentration of up to two orders of magnitude have been observed when conditions are varied over the range that might be encountered in typical laboratory dilution systems. For example, at a dilution ratio of 12, dilution temperature of 32 °C, and a residence time of 1000 ms, the number concentrations reach 6 × 108 part.

The most recent goal of our research program was to identify the optimal features of each of three garments to maintain core temperature and comfort under intensive physical exertion. Four males and 2 females between the ages of 22 and 46 participated in this study. The garments evaluated were the MACS-Delphi, Russian Orlan, and NASA LCVG. Subjects were tested on different days in 2 different environmental chamber temperature/humidity conditions (24°C/H∼28%; 35°C/H∼20%). Each session consisted of stages of treadmill walking/running (250W to 700W at different stages) and rest. In general, the findings showed few consistent differences among the garments. The MACS-Delphi was better able to maintain subjects within a skin and core temperature comfort zone than was evident in the other garments as indicated by a lesser fluctuation in temperatures across physical exertion levels.