Measurement of the Treatment Efficiency on Soot Particles Flowing into a Wire/Cylinder Filter Energized by a Repetitive Impulse Voltage Generator

The electrostatic filtration is a process that has been studied for more than one century. Its applications are very various : one of the most recent applications is the Diesel exhaust gas after treatment. In a more specific way, car manufacturers are very interested in using corona discharges to remove the soot particles from the exhaust gas. 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. Experiments have been performed on a motor test bench where temperature and flow velocity of the exhaust gas are perfectly controlled. Several configurations of power supply have been tested at four engine revolution speeds. This study showed that the combination of direct voltage (- 7 kV) and pulsed voltage (-14 kV, 3 kHz) yields very interesting results. The voltage generator that has been used to provide these voltage waveforms is a thyristors-based switch.