Continuous regeneration of an electrically heated diesel particulate trap

Abstract

A wall-flow type diesel particulate trap using electrostatic field (E-DPT) was proposed to remove soot particles exhausted from diesel engines. This device was capable of trapping soot particles by electrostatic effect by applying a direct current electric field between two electro-plates separated by 1.5 mm. Soot trapped on the plates formed bridges of soot clusters in a narrow space between the electro-plates and it was burned by Joule heating owing to the direct electrification through the bridges. When the applied voltage to the E-DPT was lower than the critical value ( Ep = 200 V), only the soot accumulation was observed. Its accumulation mechanism looked like a kind of electrostatic precipitator, and soot burning caused by the electrification through soot bridges was observed at higher applied voltages at 250-300 V. When soot accumulation and burning were balanced, a stable operation of E-DPT at 60-80 per cent removal efficiency was attained. An analysis of the experimental data on soot removal efficiency, power consumption, and heat balance during steady operation showed that the E-DPT developed is a potential system for practical application to actual diesel engines.