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낮은 엔진 부하의 운전조건에서 흡기포트 내 물 분사에 따른 가솔린 직접분사 엔진의 연소 특성
전해강,이경환,최명식,박수한,Jeun, Haegwang,Lee, Kyung-Hwan,Choi, Myungsik,Park, Suhan 한국액체미립화학회 2018 한국액체미립화학회지 Vol.23 No.2
The purpose of this study is to investigate the effect of water injection on combustion characteristics of gasoline direct injection (GDI) engine with turbo-charger under low-load operating condition. The test engine used in this study has four-cylinder and 10.2 of compression ratio. In order to study the effect of water injection ratio on combustion characteristics, the water was injected into the intake port from 10% to 50%, based on fuel injection quantity. From the experiment, it revealed that the water injection induced the improvement of fuel economy because of the advance of spark-timing by the reduction of in-cylinder temperature. In addition, the water injection caused the prolong of extension of the ignition delay and slight increase of burn duration.
김대광(Daekwang Kim),이준용(Junyoung Lee),최명식(Myungsik Choi),김광연(Kwangyeon Kim),김성태(Sungtae Kim),이승표(Seungpyo Lee) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
A lot of research has been done on internal combustion engine to reduce fuel consumption and emission. One field is being researched today is to recuperate from kinetic energy to electric energy as a vehicle deceleration status. More energy recuperation can be reduced fuel consumption. To recuperate the more electric energy, this study was applied to the high power alternator and AGM battery device and optimized voltage control. This kind of system is new generation alternator management system. The result of fuel economy test for this system showed an about 0.8~4% improvement effect.
끝단지지 로커암형 2단 가변밸브 기구에서 기계식 밸브간극 조정장치의 적용성에 관한 연구
추병재(Byeongjae Chu),김도중(Dojoong Kim),최명식(Myungsik Choi) 한국자동차공학회 2017 한국 자동차공학회논문집 Vol.25 No.4
This paper is introducing a two-step variable valve actuation(VVA) system that adopts a mechanical lash adjuster(MLA), instead of a conventional hydraulic lash adjuster(HLA). To minimize the variation of the valve lash in the assembly process, it is necessary to measure the height of the MLA pivots and the valve tips, and to compensate for the valve lash variation with cap shims of appropriate thickness. In this study, the heights of the MLA pivots and valve tips were measured by using a three-dimensional scanning method, and an algorithm was also developed to compensate for the valve lash variation. A number of tests proved that the magnitude of the valve lash could be controlled with the proposed algorithm. A single cylinder, two-step VVA system with an MLA was installed in a motor-rig test bench, and valve motions were measured by using a laser displacement sensor. When the valve lash was properly compensated, there was no serious dynamic malfunction up to the speed of 5000 engine RPM.
가변 밸브 timing과 duration이 가솔린 엔진 연비 특성에 미치는 영향
김재헌(Jaeheun Kim),배충식(Choongsik Bae),최명식(Myungsik Choi) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
An experiment was conducted to study the effects of valve events on the engine performance. A prototype gasoline direct injection engine was used to realize the independent control of four valve event parameters, namely intake valve opening (IVO), intake valve closing (IVC), exhaust valve opening (EVO), and exhaust valve closing (EVC). The EVO timing contributed to the optimization of the blowdown during the end of the exhaust stroke and the exhaust pumping work. The retardation of IVC timing allowed the engine to operate with wider throttle angle at fixed load condition, which reduced the pumping work significantly. The valve overlap was controlled with IVO and EVC. The pumping work decreased when the valve overlap position laid at the vicinity of top dead center (TDC) with sufficient valve overlap duration. The IVC and EVO played a dominant role in optimizing the fuel consumption characteristics compared to IVO and EVC. The IVC and EVO should be optimized in prior to the optimization of IVO and EVC.
이철구(Chulgoo Lee),김종대(Jongdae Kim),임태순(Taesoon Im),최명식(Myungsik Choi),방승기(Seungki Pang),함흥돈(Heungdon Ham) 한국지열·수열에너지학회 2013 한국지열에너지학회논문집 Vol.9 No.2
It has become very important for unused energy to be used for building air conditioning. Economic evaluation on energy system by using river water as a heat source, which is one of the unused energy, was carried out. The floor area of the building and the distance between heat source equipment and river was assumed 50,000 ㎡ and 200 m. General heat source system using absorption chiller-heater was used for comparing to the energy saving system, and payback period method using initial cost and running cost of two system, was used to perform economic evaluation. According to development of high capacity of water source heat pump which is appropriate for using river water, initial cost for the system has been reduced. Payback period was about 3.2 years, and this period might be shortened if nation’s economic support enact.
유지용(Jiyong Yu),정민영(Minyoung Jung),이준용(Junyong Lee),최명식(Myungsik Choi),김광연(Kwangyeon Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
ISG(Idle Stop & Go) is a system for saving fuel during idle. The purpose of ISG system is fuel efficiency, Ecofriendly brand image and for meeting the federal regulations about emission. Especially ISG of auto-Transmission vehicle can save fuel consumption about 15% in traffic-jam mode. But system price is high to equip for small or diesel vehicle, so it is hard to be adopted many kind of vehicles. So the aim of this study is to introduce development stories of reducing system price. For these one, we made mule car and we can get feasibility test for development of system control logic.