Abstract
The authors inject NO into a diesel engine intake and investigate the reduction of NOx generation at the combustion chamber at first. The result shows that 20 - 30% of the injected NO (0.225 ∼ 0.72 slm) is reduced. Discussion through the calculation of the extended Zeldovich mechanism suggests that the reduction is mainly attributed to the region where equivalence ratio ranges in 1.1 - 1.5 and that the reaction between NO and hydrocarbon species slightly contributes to the NO reduction. Moreover, another experimental result shows that the injection of NO slightly improves specific fuel consumption, e.g. 0.4% at NO injection of 0.72 slm for intake airflow of 285 slm. Calculation of reaction enthalpy of NO reduction and CO oxidation considerably meets the experimental results on the change in fuel consumption.
