Unregulated emissions from a diesel engine equipped with vanadium-based urea-SCR catalyst.

The present work is aimed at the study of number-size distribution of particles, volatile organic compounds (VOCs), and carbonyl compounds (CC) or carbonyls emitted from a 4-cylinder turbocharged diesel engine equipped with a vanadium-based urea selective catalytic reduction catalyst. The engine was run on an electric dynamometer in accordance with the European steady-state cycle. Pollutants were analyzed using an electric low pressure impactor, a gas chromatograph/mass spectrometer, and a high performance liquid chromatography system for the number-size distribution of particles, VOCs, and CC emissions, respectively. Experimental results revealed that total number of particles were decreased, and their number-size distributions were moved from smaller sizes to larger sizes in the presence of the catalyst. The VOCs were greatly reduced downstream of the catalyst. There was a strong correlation between the conversion of styrene and ethyl benzene. The conversion rate of benzene increased with increase of catalyst temperature. Formaldehyde, acetaldehyde, acrolein and acetone were significantly reduced, resulting in a remarkable abatement in carbonyls with the use of the vanadium-based urea-SCR system.