Optimal control design for lean NOx trap regeneration in diesel engines

In this paper, optimization problem of after treatment system is investigated for diesel engines with lean NOx trap (LNT). First, a control-oriented LNT model is developed based on energy and mass balancing rules. Then, the optimization problem is formulated as a dynamic programming (DP) problem under developed dynamical model constraint and a trade-off between fuel economy and NOx emission is considered in the cost function. To demonstrate the optimal control obtained by solving the proposed DP problem numerically, the parameters of LNT model are identified with a GT-power diesel engine simulator, and numerical simulation results with comparison to a conventional rule-based control strategy are shown by using the identified model.