INVESTIGATION OF ODOROUS COMPONENTS IN THE EXHAUST OF DI DIESEL ENGINES

This study investigated the odorous components in the exhaust of DI diesel engines. The complete products of combustion are H2O and CO2 and they have no odor. Therefore, other products of incomplete combustion like unburned fuel components, partially burned components, cracked products from thermal cracking and others are thought to be responsible for exhaust odor. As the THC in the exhaust is the result of incomplete combustion, it is a logical guess that THC in the exhaust would correlate with exhaust odor. This study measured THC in the exhaust, and a good correlation was found between THC and exhaust odor at different engine conditions. In the next step, GC-analysis was used to detect individual HC component, and its effect on odor formation was investigated. It is found that the low boiling point hydrocarbon components, especially CH4 in diesel exhaust has a good correlation with exhaust odor.Aldehyde is one partially burned component which has very strong odor. This study used high performance liquid chromatography to measure aldehydes, and four aldehydes : formaldehyde, acetaldehyde, acrolein and propionaldehyde are found significant in exhaust gases. Each aldehyde correlates with exhaust odor very well and formaldehyde among all aldehydes is found the most important component for irritating odor.