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 NOx 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 H₂ 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.