Effects of the Internal Shape of EGR Cooler on Heat Exchanger Efficiencies

An important goal in diesel engine research is the development of the means to reduce the emissions of nitrogen oxides (NOx) and particulate matter (PM). The use of a cooled exhaust gas recirculation (EGR) system is one of the most effective techniques currently available for reducing nitrogen oxides (NOx). However, a trade-off exists between the amount of NOx and PM emissions, especially at high engine loads. In the present study, we performed engine dynamometer experiments and numerical analyses to investigate how the internal shape of EGR coolers affects the heat exchange efficiency. Heat exchange efficiencies were examined for plain and spiral EGR coolers. The temperature and pressure distributions inside the EGR cooler were simulated in three dimensions using the commercial program FLUENT.