The influence of particle oxidation catalyst (POC) mode on emissions reduction of a turbo-charging non-road diesel under wide operating conditions

Abstract

In the present study, the influence of particle oxidation catalyst (POC) on emissions reduction of a non-road diesel engine is experimentally investigated under wide operating conditions. First, the diesel engine with four POC-aftertreatments (other reactors are kept unchanged) is tested under eight operating conditions non-road steady cycle (NRSC). Then, the diesel engine emissions with best POC-aftertreatment combination and without aftertreatment are comparatively tested under universal conditions. The experiments show that under NRSC, POC-3 which has Pt catalysts with Al2O3 support, asymmetrical channels layout and closed outlet form structure has the best overall exhaust purification, especially for nitrogen oxides (NOx) and particulate matter (PM). The PM conversions efficiency of POC-1, POC-2, POC-3 and POC-4 is 15.3%, 51.7%, 60.9% and 58.8%, respectively under NRSC. The contribution rates of emissions analysis results under NRSC indicated that a single POC mode cannot cover the whole engine operating range. Under universal characteristic test, the brake specific fuel consumption (BSFC) of original engine is a little lower than that of POC-3 in the whole engine operating conditions due to higher exhaust back pressure of POC-3. The engine with POC-3 has very good exhaust conversion efficiencies, the average conversion efficiency of NOx, PM, carbon monoxide (CO), and hydrocarbons (HC) is 96.1%, 51.9%, 77.8%, and 95.6%, respectively. The PM capture efficiency of POC-3 at low load of whole speed range and all load of medium speed are more than 50% compared to other operating conditions. There is little effect on carbon dioxide (CO2) emissions by POC.