Effects of particulate oxidation catalyst on emissions characteristic of diesel engines

Gaseous and PM emissions emitted from a heavy-duty diesel engine equipped with a Particulate Oxidation Catalyst (POC) converter were investigated on a test bench. The gaseous emissions were obtained by an exhaust analyzer and the particulate matter (PM) was collected by a Teflon membrane, while the exhaust composition was analyzed respectively before and after the POC converter. The results show that the POC exhibits a good performance on the emission control of HC, CO and PM. Within the engine operating range, the HC average reduction efficiency of 54% and the CO reduction efficiency of more than 85% under most conditions are achieved. The POC has no effect on the NO_x emission, while the effect of POC on the ratio of NO₂ to NO is significant and the specific emission of NO₂ is increased by 3 times. With the POC converter, the specific emissions of PM, soot and SOF are reduced by 45.2%~89.0%, 41.7%~93.3%, and 7.8%~97.7% respectively.