Soot Load Sensing in a Diesel Particulate Filter via Electrical Capacitance Tomography

Diesel engines are widely used in heavy duty trucks and off road vehicles due to their fuel efficiency and high power outputs. Environmental regulatory agencies have pushed ever stringent regulations on all internal combustion engines, including Diesel engines on gaseous as well as particulates (soot) emissions. In order to meet today’s and tomorrow’s stringent emission requirements, modern diesel engines are equipped with diesel particulate filters (DPF’s), as well as on-board technologies to evaluate the status of DPF. In course of time, particulate matter (soot) will be deposited inside the DPFs which tend to clog the filter and hence generate a back pressure in the exhaust system, negatively impacting the fuel efficiency. To remove the soot build-up, regeneration (active or passive) of the DPF must be done as an engine exhaust after treatment process at pre-determined time intervals. Since the regeneration process consume fuel, a robust and efficient operation based on accurate knowledge of the particulate matter deposit (or soot load) becomes essential in order to keep the fuel consumption at a minimum. In this paper, we propose a sensing method for a DPF that can accurately measure in-situ soot load using Electrical Capacitance Tomography (ECT). Simulation results show that the proposed method offers an effective way to accurately estimate the soot load in DPF. The proposed method is expected to have a profound impact in improving overall PM filtering efficiency (and thereby fuel efficiency), and durability of a Diesel Particulate Filter (DPF) through appropriate closed loop regeneration operation.