Jinwook Lee

Analysis of In-cylinder Flow in a Miller Cycle Engine with Variable IVC for HEV

For reduction of CO2 emission emitted from combustion engine, the developed nations have been focused on R&D of hybrid electric vehicle. Further more, many automobile companies are researching on various techniques related to engine used in HEV to enhance fuel economy. One of key techniques is miller cycle that control a valve timing to reduce compression stroke for saving energy and increase expansion stroke for high power. In this study, it was investigated the in-cylinder flow characteristics of miller cycle with variable intake valve timing by using the ANSYS simulation code. For simulation, the key analytic parameter defined as intake valve closing timing and cam profile. As main results, it was shown that LIVC cause a lower pressure inside cylinder and had better control turbulence intensity.

An Experimental Study on Spray Characteristics of Bio-diesel fuel in Three Injectors with Different Operating Mechanism for Common-rail System

Abstract Recently, exhaust gas regulation has been gradually strengthened due to depletion of fossil fuels and environmental prob-lem like a global warming. Due to this global problem, the demand for eco-friendly vehicle development is rapidly increas-ing. A clean diesel vehicle is considered as a realistic alternative. The common-rail fuel injection system, which is the keytechnology of the clean diesel vehicle, has adopted injection strategies such as high pressure injection, multiple injection forbetter atomization of the fuel. In addition, the emission regulations in the future is expected to be more stringent, which aconventional engine is difficult to deal with. One of the way for actively proceeding is the study of alternative fuels. Amongthem, the bio-diesel has been attracted as an alternative of diesel. So, in this study, spray characteristics of bio-diesel wasanalyzed in the common-rail fuel injection system with three injectors driven by different operating mechanism. 1. 서론

Hydraulic Modal Analysis of High-Pressure Common-rail Fuel Injection System for Passenger Vehicle

Abstract Recently, R&D demand for environmental friendly vehicle has rapidly increased due to its global environmental issuessuch as global warming, energy and economic crisis. Under this situation, the most realistic alternative way for environmentalfriendly vehicle is a clean diesel vehicle. The common-rail fuel injection system, as key technology of clean diesel vehicle,consists of a high pressure pump, common-rail, high pressure fuel line and electronic control injector. In common-rail high-pressure fuel injection system, high pressure wave of injection system and geometry of injector elements have a major effectson high-pressure fuel spray. Therefore, in this study, the numerical model was developed for analysis about the common-railfuel pressure pulsation by using AMESim code. We could secure stability of common-rail high-pressure fuel injection systemthrough optimal design of fuel line. 1. 서론 최근 세계적인 환경문제 및 에너지 안보에 따른 자동차기술 패러다임 변화에 따라 환경친화형 저연비 자동차의중요성이 점차 증대되고 있다. 특히, 유럽을 중심으로 세계 각국의 연비 및 배기규제가 강화되고 있으며 연료사용절감과 이산화탄소의 배출을 줄이기 위한 새로운 기술들이 등장하고 있다. 이에 가장 현실적인 대안으로 부각되고 있는 것이 친환경 클린디젤 자동차이다. 그 중에서 커먼레일 고압 연료 분사시스템은 클린디젤 자동차의 핵심기술로 고압으로 연료를 분사함으로써 연소성능의 개선과 배출가스 저감에 효과적인 기술로 알려져 있다