ディーゼル燃焼におけるすすと窒素酸化物のトレードオフに関する反応速度論的考察(熱工学,内燃機関,動力など)

抄録

As suggested by the equivalence ratio-temperature (φ-T) diagram, soot could be burnt off at 1800<T<2 200K where there is little formation of nitrogen oxides (NO_x). Accordingly, nonsooting and low NO_x combustion would be possible with moderate rates of exhaust gas recirculation (EGR), and without severe deterioration in combustion efficiency. However, complete burning-off of soot particles needs both sufficiently high temperatures and long residence times that would be favorable for NO_x formation. Therefore, a detailed examination of the kinetics of soot particle oxidation and NO_x formation processes would be useful. This study employs the detailed mechanisms from gas reactions to soot particle formation and oxidation, and a two-stage model is developed and used to investigate the trade-off between soot and nitrogen oxides emissions. The effects of the equivalence ratio, EGR, ambient pressure and temperature, and initial particle diameter are observed for various residence times. The results show that high rates of NO_x formation are unavoidable under conditions where high reduction rates of soot particles are obtained.