Control of Nitrogen Oxides by Exhaust Recirculation - A Preliminary Theoretical Study

The control of nitrogen oxides by exhaust recirculation has been evaluated theoretically by digital computer simulation of the engine cycle. Nitric oxide emission, power output, and fuel consumption have been considered. Preliminary results indicate that effectiveness of the recirculation method of nitric oxide control can be accounted for by the attendant shift in the peak temperature chemical equilibrium species distribution. The analysis reveals that nitric oxide reduction is highly dependent on fuel-air ratio, and somewhat less dependent on the temperature of recycled exhaust gases.