Comparison of diesel engine exhaust using chromatographic profiling techniques

An analytical method, developed for examining changes in the intensity and number of chemical compounds in the odorous fraction of diesel exhaust, has been applied to a variety of diesel engine systems. Comparisons were made using the chromatographic computer profiles of samples collected with the Diesel Odor Analysis System (DOAS) and dilution tunnel sampling systems. The different engine systems showed several areas of common peak patterns, but with distinctly different overall patterns. The benzaldehyde-odor correlation developed in a previous study worked for the engine systems tested. The differences in the overall patterns are attributed to the specific diesel fuels used and to the specific engine configurations. Samples obtained from raw and diluted (with a dilution tunnel) exhaust were compared. Diluted exhaust sample profiles were shown to contain a greater number of peaks, probably due to postcombustion reactions occurring in the dilution tunnel.