Design And Research Of DPF Regenerative Injection System Of Diesel Engine

Diesel Particulate Filter(DPF,Diesel Particulate Filter)is currently recognized as the most effective device to reduce particulate matter(PM,Particulate Matter)emissions from diesel engine.When diesel exhaust passes through DPF,PM in exhaust will be deposited and adsorbed by filters in DPF,but when the PM trapped in the DPF reaches a certain amount,it needs to be removed,that is,DPF regeneration.Summarized the advantages and disadvantages of various existing regeneration methods,propounded a new regeneration technology.In this technology,diesel is injected into diesel engine prior to the upstream exhaust pipe of Diesel Oxidation Catalyst(DOC),the PM in DPF is removed by using heat released from oxidation reaction of diesel with catalyst.The injection system is the most important part of DPF regeneration system.Its measurement accuracy and atomization quality will directly affect the regeneration effect of DPF.At present,there are few studies on DPF regenerative injection system in China,and only part of them can be designed independently.In order to solve these problems,in this paper,the design and research of DPF regenerative injection system are carried out.The main tasks completed are as follows:(1)Develop a simple structure and high precision compressed air-assisted DPF regenerative injection system independently.In order to meet the requirement of measurement and atomization,a new electromagnetic metering pump and pressure swirl nozzle were designed.The selection and design of other parts of the system are also carried out.(2)By using AMESim simulation software,the DPF regenerative injection system was modeled and simulated.The simulation results show that when the stiffness of the reset spring is4N/mm and the turn number of the electromagnetic coil is 400,the performance of the electromagnetic metering pump is better;The output flow of electromagnetic metering pump has good linear characteristics at low frequency,and when the frequency is 40 Hz,the flow rate of electromagnetic metering pump can meet the design requirements;The pressure fluctuation in the injection system pipeline is small and the injection quantity of nozzle is relatively stable.The simulation results show that the system has good fuel injection control ability.(3)The DPF regenerative injection system performance test bench was established.Pressure control unit characteristic test ? diesel fuel injection metering function test and swirl nozzle atomization characteristic test were carried out respectively.The test results show: a.The pressure regulator designed can reduce the pressure fluctuation of injection system;b.The flow consistency of the injection system is very good,between the range of 5 Hz to 40 Hz,the output flow of the system has a good linear relationship with the pulse frequency;c.The spray penetration distance and the spray cone angle of the swirling nozzle increase with the increase ofthe injection rate,and the spray penetration distance and spray cone angle can meet the design requirements of this paper.In addition,engine bench tests were carried out,and the results showed that: The designed DPF regenerative injection system is reliable and can effectively improve DOC's aftertemperature,it is also can ensure the smooth progress of DPF regeneration process.