Study Of Diesel Particulate Filter Regeneration Control System

Diesel exhaust takes more and more proportions in the air particulate pollution, and has become a hot issue of concern. Poor emission characteristics of diesel engine have become a bottleneck of its widely used. Diesel particulate filter is known as the most effective particulate aftertreatment equipment, and used more and more widely in the diesel engine. Because of DPF’s work theory, after some time there will accumulate some particulate matter in the DPF which makes the through-flow area of DPF reduced. The reduced through-flow area increases the exhaust back pressure which seriously affects the performance of engine and fuel economy. Therefore we must take certain measures to remove the particulate matter, which is called DPF regeneration. DPF regeneration is the most important and difficult problem encountered in the application of DPF currently.Based on the analysis of the difficult issues, this thesis started with the regeneration timing judgement, and selected a method of modeling the primary exhaust particulate mass from the engine. Introduces the idea of average value modeling into the model simplifies the process of particulate emissions estimate.Based on the analysis of the trap mechanism and pressure drop characteristics, this thesis established the model of DPF collection efficiency and pressure drop and simulated in MATLAB/Simulink, the focus of the simulation is the relationship between the particle collection efficiency and particle size. The influence of the wall pore diameter on the collection efficiency is also the focus. In addition, this thesis set up and calibrated a one-dimensional DPF GT-POWER model, and analysed the collection efficiency and pressure drop characteristics of the DPF. This model is different from the collection efficiency model. It is studied from macroscopic view for the DPF trap collection efficiency.Finally, the diesel oxidation catalyst and DPF temperature characteristics were analyzed, and established DOC and DPF temperature models which started with the conservation of energy. These models simulated the temperature change of DOC and DPF during work which not only provide a theoretical basis for development of reasonable fuel injection strategy, but also could effectively reduce the secondary pollution and energy consumption caused by regeneration.Based on the above research, combined with the actual situation, this thesis developed a reasonable DPF fuel injection combustion regeneration control strategy which provides ideas for solving the problem of DPF regeneration.