Strategies for emission control in diesel engine to meet Euro VI

Diesel engines are among the most effective engines in the world. Known as strong, economical and robust, they are also recognized for their traditional smoke and high level of nitrous oxides, NOx emissions. In the present study, a basic diesel engine that meets Euro III emissions standards with NOx concentration limited to 5.0 g/kW h and the particulate matter limited to 0.100 g/kW h was performed in order to evaluate its potential of attending Euro VI standards by developing Exhaust Gas Recirculation (EGR) technique. Euro VI will be used in the European community only in 2013 with NOx limited to 0.4 g/kW h and particulate matter to 0.01 g/kW h. The main idea is to achieve Euro VI emissions level, changing the EGR components and tuning the injection system. In order to reduce the investigation phase, statistics evaluation were used to define one specific speed and load that render the worst condition to create a high EGR volume at lower speed. The study was driven in two steps. Firstly, it was identified the components of EGR system which had more influence towards NOx reduction associated with fuel consumption and the particulate matter. Secondly, the components improved were implemented to analyze the engine potential. In total three different EGR configurations were performed and the best results obtained with the last version was NOx value equal 0.58 g/kW h, what means 8.6 times less than the start values and MIRA, one indicative of particulate matter, which reached 0.1 g/kW h, 62.96% smaller than 0.27 g/kW h at the beginning. Also, the specific fuel consumption achieved of 208 g/kW h was less than the value early defined as a goal which was of 210 g/kW h. After these results were obtained in the worst operational condition, it was assumed that the engine had potential to reach Euro VI. Thus, it was submitted to one integral test, the same as the one done during the certification process. The final test showed satisfactory results which means that the strategies used in the present study can be applied to get some insight into engines nowadays and in the future.