A Study on the Turbocharger Operating Characteristics of a Diesel Engine according to EGR Loop Types

In recently, various researches on technical method for reduction of PM and NOx from Diesel engine have been performed. Especially, it is considered that adoption of VGT and EGR system is essential technical method to reduce the PM and NOx emissions. And, to reduce NOx emissions, many attempt to adopt of special EGR loop systems including low pressure EGR loop are ongoing now. But, EGR system is composed with turbocharger system, so characteristics of EGR system are related with or restricted by turbocharger or boost system. In this study, it is investigated on the turbocharger operating characteristics and EGR loop characteristics in 2 types of EGR loop systems (High pressure loop EGR system and Low pressure loop EGR systems) to support basic information on the optimal EGR and VGT systems for PM and NOx reduction in Diesel engine. From theses test, it is understood that LP loop EGR systems has more safe characteristics on compressor surge limit and higher EGR rate at same A/F conditions compared with HP loop EGR system.