Particulate Regeneration Characteristics Of Diesel Particulate Filter For Heavy-duty Diesel Engines

In order to meet the more stringent vehicle emission regulations for ParticulateMatter (PM), the use of aftertreatment devices to reduce particulate emissions ofheavy-duty diesel engines will be an inevitable choice. Study of Diesel Particulate Filter(DPF) application in heavy-duty diesel engines for PM emission control is one of theleading and hot topics, and DPF regeneration technology is one of the key technologies.Firstly, this thesis ultilizes the Synthesis Gas Test Bench (SGB) and heavy dutydiesel engine test bench to study the DOC conversion efficiencyof THC, CO, andanalyze the NO oxidation ability under the different temperatures. The test resutls showthat the optimum temperature range for DOC to convert NO into NO2is from320℃to330℃, but when the temperature is less than250℃or higher than400℃, the formationof NO2will be drastically reduced. The performance of the DOC exposed to700℃orabove will be deteriorated rapidly.Secondly, the SGB was used to test the fresh and aged DOC+DPF coupledsystem by injecting HC into DOC inlet gas flow under different conditions. The testresults show that the HC injection can heat up gas temperature220°C to300°C, and theHC slip can be effectively controlled by DOC+DPF coupling system. If the inlet airtemperature is lower than270°C, the aged DOC will cause more HC slipping. Inaddition, the engine bench was used to study the temperature characteristic duringactive regeneration in DPF application. The tests results show the injection before DOCsignificantly can warm up exhaust gas flow, and the inlet temperature of DOC willaffect amount of HC slip.Finally, the flow of DOC+DPF system was modeled by AVL BOOST. The benchtest result was verified by the modeling of the effect of DOC on the optimumtemperature to generate NO2in passive regeneration and the effect of space velocity onthe HC slip inactive regeneration. The DPF system optimization suggestion on backpressure was given.