Study On Compound Regeneration Technology Of Diesel Particulate Filter Based On Thermal Power In Cylinder

Emission regulations have increasingly strict control over particulate emissions.Diesel particulate filter(abbreviated as DPF)is widely used as one of the most effective after-treatment devices for reducing diesel particulate emissions.In order to effectively control the regeneration process of DPF and ensure its safety and integrity,based on summarizing the existing regeneration methods,the DPF composite regeneration method based on the temperature rise of diesel engine thermal energy is proposed.The regeneration control strategy based on the combined use of the attached post injection(abbreviated as PoI2)and the late post injection(abbreviated as PoI1)to assist combustion has important academic value and practical significance for promoting the development of the regeneration technology of the DPF.First of all,a SQR481 A diesel engine with an in-line four-cylinder common-rail fuel injection system was set up as an experimental stand for an after-treatment system consisting of diesel oxidation catalysts(abbreviated as DOC)and DPF.On this basis,the raw particle emissions,pressure drop characteristics of DPF and DPF particle burning rate were tested,and the data of DPF soot mass,required temperature and oxygen content for safe and efficient regeneration of DPF were obtained.In order to accurately determine whether the DPF soot mass satisfies the regeneration requirements,a two-way DPF-based automatic soot mass monitoring method was proposed to determine the DPF soot mass.After that,the exhaust temperature of the engine in different load regions was analyzed,and using the thermal energy in the cylinder to increase the temperature of the exhaust gas were analyzed.The combustion control strategy of active compound regeneration with main injection delay,PoI1,and PoI2 to assist combustion under different operating conditions was proposed.For the process control of diesel DPF compound regeneration,a double closed-loop PI controller was used to control the regeneration temperature.The upstream temperature of the DOC was controlled by the inner-loop PoI2 and the intake air amount,and the upstream temperature of the DPF was controlled by PoI1 of the outer ring.Then,the composite regeneration strategy was tested by the actual vehicle,and the oxygen content and exhaust temperature data of the exhaust gas in the regenerative mode were obtained to verify the feasibility of the control strategy and method of the composite regeneration.