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LP EGR 적용을 위한 승용 디젤 엔진 보정 기법에 관한 연구
정동영(Dongyoung Jeong),정재우(Jaewoo Chung),김남호(Namho Kim),강정호(Chungho Kang),김태진(Taejin Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Diesel engine technology is developing to satisfy strong exhaust gas regulations and lower fuel economy. In the event of study, the HP EGR system which is to reduce NOx generation of the engine emission is changed to LP EGR system which investigate in NOx and BSFC respects. In structural alterations to the LP EGR, the pressure drop should be minimized in EGR gas path. And Applying the LP EGR is of benefit to reduce the NOx generation above 40% in same BSFC level, in this case, the vane control of variable geometry turbocharger is controlled in maximum compressor efficiency area, and the LP EGR valve is operated the wipe open state, the back pressure valve is controlled to consider limit A/F and reduced BSFC. And the equation of the mass flow through the nozzle is modified for EGR valve and back pressure valve. In using modified equation predicts the pressure of before back pressure valve and accompanying pressure is used to predict EGR rate. And that the predicted EGR rate is verified to compare with engine test data.
LP loop EGR 디젤 엔진의 EGR cooler 적용 특성
정재우(Jaewoo Chung),정동영(Dongyoung Jeong),김남호(Namho Kim),강정호(Chungho Kang),서영호(Youngho Seo),김병수(Byoungsu Kim),김태진(Taejin Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
In this study, an EGR system of EURO4 engine was modified to LP loop EGR system considering the minimize the pressure drop and LP EGR cooler application characteristics was investigated using various EGR cooler applications. As the investigation , LP EGR cooler fouling test was performed during 50 hr at LP loop EGR engine driving condition and as the fouling test result, EGR cooler fouling phenomena did not happened. Also, EGR gas cooling performance and pressure drop through EGR cooler was measured at engine test. From LP loop EGR engine tests, Engine fuel economy performance was improved about 4%∼7% compared with the base EURO 4 engine value at similar NOx emission level, And it is found that intake manifold temperature is effected by EGR cooler, EGR/ fresh air mixing and intercooler cooling capacity. On the other hand, EGR cooler has some effects on cooling the EGR gas upstream of EGR valve and compressor, EGR cooler restrict the gas temperature in LP EGR system and protect the LP EGR components. So high EGR rate could be realized by application of a LP EGR cooler. In Hybrid EGR system, monitoring of LP EGR fraction has been point out as a technical problem, so, in this study, a LP EGR mass flow rate measurement method using EGR cooler was made to attempt.