Pollution duality in turbocharged heavy duty diesel engine

Diesel engine designers are faced with increasingly stringent social demands to reduce emissions while maintaining high performance. Several strategies are considered, such as the advanced fuel system, the cooled exhaust gas recirculation (EGR), the particulate filter, the NOx after-treatment, the oxidation catalyst, the advanced control techniques and the alternative combustion. These strategies have been tuned to achieve the lowest engine exhaust gas emissions. The major problem of diesel engine pollution is the NOx and soot formation. Their antagonistic evolution according to the air/fuel ratio is well-known, and requires a good compromise. In this article, a numerical investigation was carried out using the KIVA-3v code. The aim deals with the influence of some engine parameters on the performances and the pollutant (NOx-soot) formation of a turbocharged heavy duty direct injection diesel engine. The numerical simulations were achieved to capture independently the effects of engine operating parameters such as the fuel injection timing, the fuel injection duration, the piston bowl diameter and the EGR rate. The obtained results are discussed and some conclusions are developed.