Simulation Study Of Exhaust Gas Recirculation On Low Speed Two Stroke Diesel Engine

Tier III emission regulation focusing on marine diesel engine is going to take effect in 2021, which requires a large scale of reduction on NOx emission. In order to study the effect of EGR technique on marine diesel engine and the feasibility of using the technique to meet Tier III, this research studied low speed diesel engine 6S35 manufactured by Shanghai Hudong Heavy Industry, with reference of experiment data, using simulation method to compare different kinds of EGR systems and study the influence of EGR on low speed engine.During one dimensional simulation, this research studied different EGR systems on low speed engine, figured out that High pressure loop EGR system with sequential turbocharge system can cover both high EGR rate working situation and regular working situation. Also, EGR rate controlling method is acquired. Meanwhile, the research found out the EGR influence on low speed engine on quasi dimensional combustion model. Some of the original designs of engine are no longer fit the engine under EGR mode, therefore injection timing, cam timing and EGR system are optimized so that BSFC is lowered and NOx emission is not higher.More accurate EGR rate fitting Tier III regulation must be acquired. This research used 3dimensional calculation to have deep insight of working process of low speed engine and the influence of EGR. This gave guidance to EGR rate controlling of low speed engine.