Study On CDPF Passive Regeneration For Heavy-duty Diesel Engine

With the increasingly stringent requirements for heavy duty diesel engine emission regulation,Catalytic Diesel Particulate Filter?CDPF?has become an indispensable part of heavy duty diesel engine aftertreatment system.Passive regeneration is an important way to achieve regeneration process.In this paper,passive regeneration is study using that three method of engine bench test,one-dimensional passive regeneration model based on AVL BOOST and zero-dimensional passive regeneration model based on Arrhenius equation.The influence factors and regeneration process of passive regeneration are studied by the experiment of engine bench and ash fast loading device,and the simulation based on BOOST model.The results show that with the increase of initial soot loading,bed temperature and NO₂ concentration,soot oxidation rate of passive regeneration increase;ash content and the exhaust gas flow has no effect on soot oxidation rate of passive regeneration.In the process of passive regeneration,the difference of pressure drop is divided into three stages:fast descent,rapid descent and slow descent.The presence of ash can occupy the soot position of deep filtration,which leads to the decrease of pressure drop,and the difference between the three stages is weakened or even disappeared.Based on the Arrhenius equation model method,the passive regenerative balance curve is established,and it is found that when the initial soot loading of CDPF is certain,the relationship between the ratio of NO_x and soot emission and CDPF bed temperature is the trade-off relationship in the balance state;When the initial soot loading increases,the balance curve will move to the CDPF bed temperature reduction and the ratio of NO_x and soot emission reduction.The part of suitable operating mode for passive regeneration of engine is determined.A simple conception of passive regeneration control strategy based on soot load prediction model,engine passive regeneration MAP and engine exhaust management is proposed.The study of CDPF passive regeneration can provide some guidance for the development of control strategy and European VI aftertreatment system.