(1.School of Automobile and Traffic Engineering, Jiangsu University,Zhenjiang 212013,China;2.School of traffic engineering ,Nanjing institute of industry technology,Nanjing 210046,China)
Fe-based additives (Fe-FBC) were added to China V diesel fuel according to the mass fraction of 100 mg/kg, 200 mg/kg and 300 mg/kg in order to prepare the blended fuels of Fe100, Fe200 and Fe300. On a self-made bipolar charge test bench, the effect of charge voltage on the charge characteristic of exhaust particles was analyzed. Engine exhaust particle size device and Malvern ZEN analyzer were used to further measure the particle size distribution, surface charge and DPF number concentration collection efficiency. The results show that the particle size of peak concentration becomes smaller with the increase of Fe content under the same engine operating condition. Electrical charge agglomeration(ECA)can aggregate the small and medium-sized particles to the larger particles in the exhaust of diesel engine. Fe-FBC can improve aggregation efficiency of particles and so the aggregation efficiency of Fe300 fuel particles is higher at the same charge voltage. Increasing the charge voltage can increase the Zeta potential and charge on the particle surface. The charge performance of exhaust particles improves significantly after adding Fe-FBC. The increase rate of Zeta potential and charge on the surface of Fe300 particles is the highest at the charge voltage of 15kV. ECA can increase the DPF collection efficiency at 6.04 ~ 12.4 nm. The DPF efficiency of diesel and Fe300 increases by 12.2% and 23.8% respectively at the charge voltage of 15 kV.