Aftertreatment control and adaptation for automotive lean burn engines with HEGO sensors

Abstract

Control of aftertreatment systems for lean burn technology engines represents a big challenge, due to the lack of on-board emission measurements and the sensitivity of the hardware components to ageing and sulphur poisoning. In this paper, we consider the control and adaptation of aftertreatment systems involving lean NO x trap (LNT). A phenomenological LNT model is presented to facilitate the model-based control and adaptation. A control strategy based on the LNT model and HEGO (heated exhaust gas oxygen) sensor feedback is discussed. A linear parametric model, which is derived by exploiting the physical properties of the LNT is used for adaptation of trap capacity and feedgas NO x emission models. The conditions under which parameter convergence will be achieved are derived for the proposed adaptive scheme. Simulation results for different scenarios are included to demonstrate the effectiveness of control and adaptation.

Automotive Powertrain Control - A Survey

“…In an effort to relax the computational intensity associated with the nonlinear parametric model used in [57], a new purge model [48] is exploited by the authors of [58] to develop an adaptive control strategy that is more feasible for real-time implementation in a computationally resource-constrained environment. By incorporating the physical properties of the system and properly choosing the structure for the LNT model and parameterization for the uncertainties, a linear parametric model is developed in [58] for on-line adaptation.…”

“…By incorporating the physical properties of the system and properly choosing the structure for the LNT model and parameterization for the uncertainties, a linear parametric model is developed in [58] for on-line adaptation. Results show that, when integrated with model-based LNT control, the adaptation improves the aftertreatment control robustness by maintaining the desired tradeoffs between fuel economy and emissions.…”

Control oriented model of a lean NOx trap for the catalyst regeneration in a 2.2 L direct injection diesel engine

“…For the precise control of the LNT regeneration, a control oriented LNT model should be developed by estimating the stored NO x amount or the NO x storage fraction in the catalyst (Canova et al, 2010;Larsson et al, 1999;Midlam-Mohler, 2005;Nauta, 2010;Kim et al, 2003;Sun et al, 2004;Lee et al, 2013;Lee and Han, 2014). The control oriented LNT model would let the ECU (Engine Control Unit) designer determine when the regeneration of the catalyst should be initiated and ended to satisfy both minimal fuel consumption and higher NO x conversion efficiency.…”

An optimization method of LNT aftertreatment system based on discrete approximation

“…LNT 1 x = 0.9 LNT (Chen and Wang, 2014, Han and Lee, 2015, Wang et al, 1999, Sun et al, 2004, Graff, 2006)…”

“…(NOx) (Johnson, 2015) LNT(Lean NOx Trap) SCR(Selective Catalytic Reduction) (Sun et al, 2004, Graff, 2006, Wu, 2011, Xu and McCabe, 2012 NOx Wang, 2009, Hsieh et al, 2010) NOx (Bellman, 1954, Kirk, 2004) (Kang et al, 2001) LNT Fig. 2 Target diesel engine system with LNT aftertreatment system.…”