Control-oriented modeling of diesel oxidation catalyst

Abstract

Diesel oxidation catalyst outlet temperature control is crucial for heat management to realize diesel particulate filter active regenerative control. In order to control the temperature of the active regeneration process in the filter, the temperature response process of the semi-physical oxidation catalyst model structure is proposed as a multi-stage inertia plus delay, and the equivalent inlet temperature step of the fuel oxidation reaction of the exhaust pipe. Combined with the test test, the control oriented oxidation catalyst model is established.A control-oriented oxidation catalyst model was constructed. By analysed the oxidation catalyst working process, the main chemical reactions, heat and mass transfer processes occurring inside the carrier were analyzed. Three-dimensional CFD model and one-dimensional chemical reaction kinetics model were established respectively. The radial and axial temperature distribution of the carrier was analyzed by model simulation. Based on the analysis of the system characteristics, the multi-step inertia plus delay semi-physical model structure was proposed. Combined with the test, the control oriented oxidation catalyst model is established. Select the appropriate working conditions to identify and verify the model parameters. The results show that the third order model can well indicate the temperature response characteristics of the oxidation catalyst outlet temperature. Considering the complexity of the system, the first-order and third-order model are selected as the basis of the control system design.