Development of EGR system for industrial diesel engine using CFD approach

In accordance with the rising concern about global environmental protection, exhaust emissions regulations for industrial diesel engines are also being strengthened worldwide in stages. In order to comply with the EPA Tier3 and interim Tier4 level, EGR (Exhaust Gas Recirculation) system is recognized as one of the most potential technologies to reduce Nitrogen Oxide (NOx), but there were concerns about durability deriving from the fuel quality and cost increase from additional parts like as EGR cooler, reed valve and EGR valve. To overcome these problems and to fulfill the market demands for industrial diesel engines, such as low cost, compactness, high output and high durability, most appropriate system should be chosen for each engine type. This paper describes two different techniques to optimize the different EGR systems for engines with different combustion systems, namely optimization process of internal EGR for In-Direct Injection system (IDI) by using one dimensional engine cycle simulation and distribution improvement of external EGR for Direct Injection system (DI) by using 1D-3D coupled computational fluid dynamic (CFD) simulation.