Integration of Reformer Model-Based Estimation, Control, and Diagnostics for Diesel LNT-Based Aftertreatment Systems

摘要

Future government emission regulations have lead to the development and implementation of advanced aftertreatment systems to meet stringent emission standards for both on-road and off-road vehicles. These aftertreatment systems require sophisticated control and diagnostic strategies to ensure proper system functionality while minimizing tailpipe NO_x and PM emissions across all engine operating conditions. In this paper, an integrated algorithm design approach with controls and diagnostics for an aftertreatment system consisting of a fuel doser, fuel reformer, LNT, DPF, and SCR is discussed. From a high level advanced algorithm design perspective, the aftertreatment strategies are categorized into four areas: 1) model-based temperature controls with fuel reformer H_2 and CO yield consideration, 2) estimation of non-immediately available signals, 3) evaluation of system performance for long-term and short-term compensation, and 4) diagnostics for the purpose of safety and tolerant controls. Advanced methodologies, such as optimal cascade control, Kalman filtering, nonlinear system identification and (sliding-mode) observer design are integrated to optimize and enhance the overall system performance and reliability. Vehicle and engine testing as well as simulation results are shown.