Effect of High and Low Pressure EGR on Diesel Engine Matched with Mechanical Turbo-compound

Abstract

The mode of exhaust gas recirculation (EGR) and the flow of recirculated exhaust greatly impact the exhaust heat recovery of the mechanical turbo-compound. A matching mechanical turbo-compound of the diesel engine is established with GT-power software to study the effect of EGR mode and EGR rate on it, and the effect of EGR rate on the working performance of diesel engine and the mechanical turbo-compound under high-pressure EGR mode and low-pressure EGR mode is also studied. The results show that compared with the original engine, the effective thermal efficiency of the diesel engine matched with mechanical turbo-compound has been improved. Under the two EGR modes, as the EGR rate increase, the effective thermal efficiencies of diesel engine matched with mechanical turbo-compound and the original engine are decreasing. Under the maximum torque condition, the fuel economy of mechanical compound turbine diesel engine matched with low-pressure EGR system is better than with high-pressure EGR system; while underrated power condition, the fuel economy difference of mechanical compound turbine diesel engine matched with high-pressure EGR system and low-pressure EGR system is small.