Dynamic optimization of lean burn engine aftertreatment

The competition to deliver fuel efficient and environmentally friendly vehi cles is driving the automotive industry to consider even more complex power train systems. Adequate performance of these new highly interactive systems can no longer be obtained through traditional approaches, which are intens ive in hardware use and final control software calibration. This paper expl ores the use of Dynamic Programming to make model-based design decisions fo r a lean burn, direct injection spark ignition engine, in combination with a three way catalyst and an additional three-way catalyst, often referred t o as a lean NOx trap. The primary contribution is the development of a very rapid method to evaluate the tradeoffs in fuel economy and emissions for t his novel powertrain system, as a function of design parameters and control ler structure, over a standard emission test cycle.