Exploration on the emissions and catalytic reactors interactions of a non-road diesel engine through experiment and system level simulation

In this paper, the emission characteristics and catalytic reactors interactions of a non-road diesel engine are investigated under non-road transient cycle (NRTC) by experiment and system level simulation. The results showed that the overall emission conversion efficiency of hydrocarbon (HC), carbon monoxide (CO), nitrogen oxides (NOX) and particulate matter (PM) is 96.68 %, 91.45 %, 97.67 % and 93.33 %, respectively under NRTC in experiment. In addition, the interactions of each catalytic converter for emissions under NRTC have been obtained through simulation. When the diesel oxidation catalytic (DOC) temperature is higher than 600 K, CO and HC emissions basically achieve almost 0 through DOC purification. Furthermore, DOC can convert nitric oxide (NO) into nitrogen dioxide (NO2) which provides strong oxidation for the passive regeneration of diesel particulate filter (DPF). The NO reaction rate is closely related to DOC temperature. And the average conversion efficiency from NO to NO2 in DOC is 40.36 %. Moreover, the DOC inlet pressure has almost no effect on the conversion of HC and CO. When the temperature of selective catalytic reduction (SCR) is higher than 500 K, the averages NOx conversion efficiency of SCR is up to 98.74 %. And ammonia purification catalyst (ASC) can further reduce NO emissions while absorbing slip ammonia. When the inlet temperature of DPF is more than 520 K, it has almost no effect on the oxidation of PM. The PM conversion efficiency of aftertreatment system (ATS) is mainly affected by the PM collection efficiency of DPF. The average PM collection efficiency of DPF is 53.32 %, while the PM conversion efficiency of ATS is 91.54 % by simulation. Although DPF will convert PM to CO, these CO cannot be completely converted into carbon dioxide (CO2). So the CO conversion efficiency of ATS is lower than that of DOC.

Automated summary

In this paper, the emission characteristics and catalytic reactors interactions of a non-road diesel engine are studied under non-road transient cycle (NRTC) through experiment and simulation. The results show high emission conversion efficiencies for HC, CO, NOX, and PM. The interactions of each catalytic converter are obtained, revealing the effectiveness of DOC in reducing CO and HC emissions and converting NO to NO2. The SCR and ASC also contribute to NOx reduction, and the DPF plays a crucial role in PM collection and oxidation.