Study On After-Treatment Technology Of Diesel Vehicle Particulate Based On Fuel Injection Assisted-Regeneration Of DPF

Since the emission regulations are becoming more and more rigorous throughout the world, after-treatment technology has been paid more attentions from the viewpoint of controlling diesel vehicle emission. And diesel particulate filter (DPF) has been recognized one of the most effective ways in particulate matter (PM) emission control. But the problem of removing PM deposited in DPF, which is called regeneration process, is still not solved very well nowadays. Aiming at reducing the complexity and energy consumption of the regeneration system, this Thesis presents the research results achieved by the author on the issue of fuel injection assisted-regeneration of particulate trap for diesel vehicles.Firstly, a diesel particulate filter (DPF) system based on fuel injection assisted-regeneration is designed. In the system, the exhaust gas temperature will be enhanced by two ways:if the temperature is not heated up to regeneration temperature by a burner designed in this thesis, additional diesel fuel is sprayed before a diesel oxidation catalyst (DOC) to enhance exhaust temperature further by HC's oxygen process. The scheme of the after-treatment system is helpful for energy efficiency. And auxiliary air used by the burner and the after-treatment system is supplied from the boosted engine intake.Secondly, two kinds of burners have been designed aiming at heating the exhaust gas. And the performance of each burner is evaluated by experiment. One of the burners, which called vaporizing-type burner, can work at the entire engine MAP. In the condition of no auxiliary air will be supplied from the turbocharger, combustion can be completed relying on the exhaust gas. In order to safely regenerate the DPF, the uniformity of temperature before DPF is improved; the factors which influence the peak temperature in DPF is investigated by simulation and experiments methods, such as:DPF material, particulate matter characteristic, exhaust gas characteristic. HC and CO emission is also controlled in the regeneration process.Thirdly, a three-dimensional MAP of engine speed, exhaust temperature, exhaust backpressure is designed aiming at estimating the mass of particulate matter retained in the DPF. The engine map is divided into several areas based on the characteristic of the after-treatment system for the sake of predigesting the control strategy. At each area, the fuel and air supply of the after-treatment system is fixed. The results of the regeneration tests show that the exhaust gas temperature can be raised to 600 deg. C in different areas of the engine map.At last, the characteristic of the DPF resistance and energy management of the burner type after-treatment system are studied. The entire system is integrated on a light duty diesel vehicle, which can meet Chinese III before. And it can meet Chineseâ…£emission regulation after equipped with the DPF system.