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.