Rapidly Pulsed Reductants in Diesel NOx Reduction with Lean NOx Traps

摘要

RPR performance is dependent on a large number of operating parameters. For the temperature range of interest in this study (T>450°C): 1. The NOx conversion of RPR using is very dependent on the type of HC reductant. Generally, the NOx conversion increases as the reactivity of reductant is increased. 2. The existence of an optimal pulsing frequency was observed which resulted in maximum NOx conversion at a given fuel penalty. This optimal frequency was a dependent on a number of operating conditions (e.g. temperature, space velocity, reductant type). 3. As the temperature was increased the optimum frequency increased. 4. It was needed to have rich flow during pulses to obtain high NOx conversion; however, the cycle averaged flow was always net lean. The amount of pulse amplitude (richness) required for each reductant was different. Future/ongoing work: Understanding of the limiting factors (kinetics, transport, storage capacity, etc.) at different operating regimes, in order to obtain a valid theoretical model for the process.