Electrostatic filtration is a process that has been studied for more than a century. One of the most recent applications is Diesel exhaust gas aftertreatment. More specifically, car manufacturers are very interested in using electrical discharge phenomena to remove the soot particles from exhaust gases. This process could be a feasible alternative to the Diesel particulate filter used at the present time. The aim of this paper is to investigate the effects of repetitive voltage impulses on the treatment efficiency on soot particles and to compare results with those achieved when a DC supply is used. The study was divided into two steps: in the first, a study of the modes of discharge which develop in an electrostatic precipitator allows us to optimize both the geometry of an ESP and a hybrid pulsed power/direct voltage supply. This study was performed without gas flow. In the second step, investigations concerning treatment efficiency were carried out under practical conditions using an engine test bench. Results show that the combination of direct voltage (-7 kV) and pulsed voltage (-14 kV, 3 kHz) provides treatment efficiency close to 75% using electrical power three times lower than that required using a DC supply. PACS. 52. Physics of plasmas and electric discharges-07.89.+b Environmental effects on instruments