Advancing the Regeneration of Diesel Particulate Filters through the Utilization of Ozone Generated by Non-Thermal Plasma: An Experimental Investigation

Particulate matter (PM2.5) from diesel engines poses significant environmental and health risks. Diesel Particulate Filters (DPF) mitigate emissions but suffer from soot accumulation, which increases back pressure and requires regeneration, often impractical at low urban driving temperatures. This study investigated Non-Thermal Plasma (NTP)-generated ozone and hydrogen for DPF regeneration, assessing their impact on particulate matter, pressure drop, and DPF lifespan. Experiments utilized a 4-stroke diesel engine, with ozone produced from pure oxygen or air through NTP at 20 VPP, 50-1000 Hz, and 5-10 L/min, and introduced into a soot-filled DPF at 200°C. Regeneration was monitored by differential pressure. Findings showed ozone effectively reduced DPF pressure drop, with pure oxygen at 1,000 Hz and 5 L/m yielding the best regeneration above 5,000 ppm ozone. Lower flow rates increased ozone concentration. Hydrogen addition of 3-6% did not significantly improve efficiency and caused system anomalies, possibly due to the formation of water. In conclusion, ozone is a promising, low-energy DPF regeneration solution, effective at temperatures ranging from 200-300°C to 600°C, which is ideal for urban conditions. Optimizing ozone generation is crucial, while hydrogen addition may not be beneficial.