We are developing advanced combustion, aftertreatment, and controls technology for light-duty diesel engines for low emissions applications. Recent and current efforts have successfully achieved U.S. Tier II, Bin 5 compliance using alternative combustion, high levels of EGR, and advanced aftertreatment systems. The key to reaching these extremely stringent emissions regulations lies in the engine control system. SwRI has developed a family of control algorithms that orchestrate harmony among the fuel injection, boost, EGR, and aftertreatment systems during steady-state and transient conditions.