Fundamental Investigation of NOx Formation in Diesel Combustion Under Supercharged and EGR Conditions
Aim of this study is to clarify the NOx formation mechanism in diesel combustion under high-supercharged condition. Effects of ambient conditions and fuel injection parameters on diesel combustion were investigated using a constant volume chamber. NOx formation process was investigated using a total gas-sampling device. The results indicate that by using the above experimental setup it is possible to realize entirely diffusion combustion like what seen in the highly supercharged condition. Increasing ambient pressure up to 8MPa with high injection pressure shortens the ignition delay and offers a heat release rate proportional to the fuel injection rate with a short combustion duration. Increasing ambient pressure gives a higher NOx formation rate and final NOx concentration. This is due to enhancement in the fuel-air mixing which promotes the heat release.