Effect of DOC/CCRT Aging on Gaseous Emission Characteristics of an In-used Diesel Engine Bus

Abstract

Based on heavy chassis dynamometer, an experimental study was conducted in diesel bus with China Stage Ⅲ, which investigated the effects of gaseous emission characteristics under CCBC driving cycle, such as carbon monoxide (CO), total hydrocarbons (THC), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxides (NO<i>x</i>) and carbon dioxide (CO2) with the fresh/aged oxidized catalyst (DOC) and oxidation catalysts coupled catalyzed particulate trap (DOC+CDPF, referred CCRT). The results showed that using fresh and aged DOC/CCRT, the diesel bus could reduce CO, THC and NO emissions, meanwhile increase NO2 emissions, but NO<i>x</i> and CO2 emissions remained basically unchanged. In idle speed, acceleration, deceleration and constant speed of working conditions, the diesel bus using the fresh DOC had better oxidation efficiency of the CO and THC emissions than the bus using the aged DOC. The diesel bus using the fresh CCRT had higher oxidation efficiency of THC emissions, but lower oxidation efficiency of CO emissions than the bus using the aged CCRT. The diesel bus using the fresh DOC/CCRT had a higher rate of NO emissions reductions and NO2 emissions increments than the bus using the aged DOC/CCRT, but it did not basically affect the NO<i>x</i> emissions.