Experimental study of the active and passive regeneration procedures of a diesel particulate filter in a diesel methanol dual fuel engine

The diesel methanol dual fuel (DMDF) technology has been used in diesel engines to reduce the nitrogen oxides (NOX) and particulate matter (PM) emissions in past years. A combination of a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) is applied on DMDF engines to meet severer emission standards in this study. The DOC was modified to produce adequate nitrogen dioxide (NO2) in the presence of the high hydrocarbon and carbon monoxide emissions formed by DMDF mode. During tests, the effect of methanol substitution ratio (MSR) and DOC inlet temperature on DOC performance was studied. Moreover, the effect of MSR on the active and passive regeneration of DPF was investigated. Results show that at high DOC inlet temperatures (> 190 degrees C), the DMDF mode combined with DOC achieves the high DPF inlet temperatures and the high NO2/PM ratio, which is benefit for passive regeneration. During active regeneration, the initial regeneration temperature, the fuel penalty and the emissions of PM, particulate number (PN), NO2 and carbon dioxide (CO2) after the DPF at MSR40 are lower than those at MSR0. The emissions of methanol (CH3OH) and formaldehyde (HCHO) after the DPF at MSR40 are higher than those at MSR0. During passive regeneration, the regeneration rate at MSR40 is higher than that at MSR0, as well as the emissions of PN, CH3OH and HCHO after the DPF. While the NO2 and CO2 emissions after the DPF at MSR40 are lower than those at MSR0.