Evaluation of exhaust odor in a direct injection diesel engine

Abstract

Exhaust odor is one of the demerits in a direct injection diesel engine. Usually, the evaluation of exhaust odor involves sensory assessment by nose panel and it is difficult to evaluate the odor level using a chemical analyzer, because there are many kinds of odor components in the exhaust gas. In this study, pH measurement of an aqueous solution of a condensed component of exhaust gas, formaldehyde measurement with the reduction FID and sensory assessment using an eye irritant are investigated. It was found that the pH method using a gas sampling bag is simpler and more exact than the cold trap method; however, the correlation between the pH value and the sensory assessment varies with operation conditions. On the other hand, the formaldehyde concentration shows a correlation with the degree of eye irritant.