Analysis of temperature and pressure characteristics in catalyzed diesel particulate filter operation for heavy-duty diesel engine

Abstract

• Pressure characteristics of the soot loading process in CDPF is clarified. • Temperature characteristics of active regeneration process in CDPF is proposed. • The effect of the flow parameters on pressure and temperature are studied. • A self-defined transient cycle is used to reflect the actual road conditions. • The soot oxidation process is divided into stages I and II. Catalyzed Diesel Particulate Filter (CDPF) provides an efficient method for removing particulate matter emissions to meet stringent soot emission legislation for diesel engines. In order to clarify the temperature and pressure characteristics of CDPF during the soot loading and regeneration process, in this study, a self-defined transient cycle is used for the soot loading test and combined with 1D simulations to reveal the pressure field. In addition, the effect mechanism of initial soot loading and inlet parameters on temperature and soot characteristics was investigated through the results of regeneration experiments and 3D simulations. The results show that the initial soot loading amount and exhaust flow rate affected the pressure drop of CDPF more than that of the engine. The total pressure drop of the CDPF varied linearly with the increasing exhaust flow rate and soot loading. Among the four pressure drops, the soot layer pressure drop had the highest proportion and the most significant change. During the active regeneration of CDPF, the temperature near the CDPF outlet was the highest (TS3), and TS1 was the lowest, in the axial direction, TS4 and TS5 in the radial direction were the highest. In addition, the soot combustion process can be divided into stages I and II based on the soot oxidation speed. The larger initial soot loading, the higher inlet temperature, the faster exhaust flow rate, and greater O 2 concentration all resulted in the shorter stage I, the larger soot oxidation speed, the faster temperature rise, the larger region of high temperature in CDPF. And the inlet temperature had the greatest impact on the regeneration process, followed by initial soot loading and O 2 concentration, and the exhaust flow rate had the least impact. There is a reversed change in the propagation direction during the oxidation of soot.