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

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 NOx 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 NOx 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. Copyright # 2004 John Wiley & Sons, Ltd.