An adaptive control strategy for urea-SCR aftertreatment system

Hydrocarbons, carbon monoxide, and other polluting emissions produced by diesel engines are usually much lower than those from gasoline engines. However, higher combustion temperature in diesel engines cause substantially larger percentage of nitrogen oxides (NO_x) emissions. Selective catalyst reduction (SCR) is a well proven technology for reducing NO_x emissions from automotive sources and in particular, heavy-duty truck diesel engines. In this paper, we develop a linear parameter varying (LPV) control design method for the urea-SCR aftertreatment system to minimize the NO_x emissions and ammonia slippage downstream the catalyst. Performance of the closed-loop system obtained from the interconnection of the SCR system and the output feedback LPV control strategy is then compared with other control design methods including sliding mode, and observer-based static state feedback methods.