| In recent years, most of the cities and regions in our country are plagued by serious smog, and the air pollution is more and more serious, therefore, as a big source of the air pollution, the motor vehicle exhaust pollutant emission problems are closely watched by the government and the people in the society. The PM( Particulate Matter) in China has become one of the major air pollutants, however, as an important source of the PM emissions, the problem of diesel engine emission control has received much attention. In order to control the vehicle emissions effectively, the motor vehicle emission regulations, at home and abroad, arised at the historic moment, and they all show the tendency of more and more stricter. In 2014, the European Emissions Standards ? has begun to implement in Europe; in our country, the Diesel Emissions Standards ? has also began in July 2013, and the Diesel Emissions Standards ? will commence in 2017. In order to meet the latest national emission standards, and control the diesel particulate emission problems, the development and the application of diesel exhaust aftertreatment system has received much attention from all walks of life.As the effective means to reduce the diesel particulate emission, the Diesel Particulate Filter is accepted. Relatively speaking, the development degree of filter material in DPF has been relatively mature, however, the DPF regeneration technology has become the current technical difficulties of whether the DPF can work normally. Hence, in view of the DPF regeneration technology difficult problem, this paper puts forward a method which adopts fixed exhaust back pressure valve value that according to the working condition of zoning as the trigger condition of the DPF regeneration system. Through the Secondary Fuel Injection of the active regenerative way, with the Diesel Oxidation Catalyst is auxiliary, this paper has carried on the design research and the simulation analysis of regeneration control system of DOC+DPF. In this paper, the main contents and results are as follows:(1) The design of the control system of regeneration of DOC+DPF. The content mainly includes the determination of initial carbon loading, the judgment of the trigger condition and timing of the regeneration system, the design of the system regeneration strategies, the choice of the measures to raise the temperature in the process of the regeneration, the design of the fault diagnosis system and the whole working process instruction of the regeneration system and so on.(2) Set the aftertreatment models by AVL Boost. The content mainly includes to build the aftertreatment models of DOC and DPF, based on simulation and the result analysis. According to the simulation results, the conclusion is as follows: 1) The inlet temperature of DOC has a great influence on exhaust temperature rise and the hydrocarbon conversion, when the range from 220? to 330?, the exhaust gas temperature and the hydrocarbons conversion rate are significantly increasing, the temperature amplitude and the hydrocarbons conversion rate changes quickly; 2)If the requirement for system control accuracy is not high, the influence of the pressure drop in DOC is negligible, because the influence of DOC pressure drop is merely around 1/20 to 1/35 compared with the DPF pressure drop; 3) The pressure drop increases with the increase of the exhaust mass flow, the rise of the exhaust temperature and the increase of the carbon loading, and its growth trend is a linear relation.(3) The configure parameters for the regeneration control system of DOC+DPF. The content mainly includes the characteristic analysis of the aftertreatment models of DOC and DPF, and the analysis of the results of the simulation research, finally to choose the reasonable control parameters. The control parameters include T0(the lowest inlet temperature of DOC), CO2(the exhaust oxygen content through the DPF), TDPF(the combustion temperature of DPF in the process of regeneration) and t DPF(the scheduled time of TDPF in the process of regeneration), TCAU(the high temperature warning thresholds in the process of regeneration), TMAX(the peak temperature limit in the process of regeneration), the exhaust back pressure valve value and the fuel injection quantity under the different working areas in the process of regeneration.(4) The application architecture diagram of the regeneration control system. The content mainly includes the trigger of the regeneration system, the choice of the regeneration measures and a detailed description of the part of the fault diagnosis system architecture.(5) To simulate the regeneration control system by using AVL Boost, and through the simulation results to verify the feasibility of regeneration control system. |
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