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2단 연료 분사를 통한 DME 예혼합 압축착화 엔진 연소 개선
윤현숙(Hyeonsook YOON),배충식(Choongsik Bae) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41
Premixed charge compression ignition combustion with a two-stage fuel injection strategy using dimethyl-ether, a gaseous fuel and diesel, a liquid fuel, was investigated in a single cylinder direct-injection compression-ignition engine. The combustion performance and exhaust emissions were tested by varying the second injection timing for dimethyl-ether and diesel respectively. The experiments were carried out under low load and low speed conditions. The first injection was injected at the early stage of the compression stroke to gain enough time for premixed mixture formation. The injected fuel quantity of the first injection was varied corresponding to the fixed load. A small quantity of second injection was applied to control the premixed charge combustion with various timings near the top dead center. With the second injection near the top dead center, the combustion efficiencies improved for both dimethyl-ether and diesel. By the late second injection, the combustion phase was retarded and lengthened, and hydrocarbon and carbon monoxide emissions were reduced.
DME 직접분사식 압축착화 엔진에서 파일럿 분사의 영향
윤현숙(Hyeonsook Yoon),배충식(Chongsik Bae) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The dimethyl-ether (DME) combustion with pilot injection was investigated in a single cylinder direct injection diesel engine equipped with the common-rail injection system. Combustion performance and emissions were tested with dimethyl-ether. The main injection timing was at the top dead center, which were the best timings for maximum power output. The total injected fuel mass was fixed 22㎣ per cycle at 800 rpm. The fuel quantity and the injection timing of the pilot injection were varied from 8 to 20% of the total injected mass and from 50 to 10 crank angle degree before the main injection timing, respectively. The ignition delay decreased with the pilot injection. The indicated mean effective pressure increased when dimethyl-ether was pilot-injected at 20 crank angle degree before the main injection timing. DME showed reduction in emissions, such as particulate, hydrocarbon, carbon monoxide and nitric oxides. The hydrocarbon and the carbon monoxide emissions were increased when the pilot injection timing was advanced. The nitric oxide emission was increased by 14% with 8% of pilot injection. Bigger amount of DME pilot-injection decreased nitric oxide emission.
DME 예혼합 압축착화 엔진에서 질소와 이산화탄소의 영향
장진영(Jinyoung Jang),윤현숙(Hyeonsook Yoon),염기태(Kitae Yeom),배충식(Choongsik Bae) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The combustion and exhaust emission characteristics were investigated in an DME fueled HCCI engine. Carbon dioxide, nitrogen and mixed gas, which was composed of carbon dioxide and nitrogen, were used as control parameters of combustion and exhaust emission. As the oxygen concentration in induction air, which was occurred by Carbon dioxide, nitrogen and mixed gas, was reduced, the start of auto-ignition was retarded and the bum duration was extended due to obstruction of combustion and reduction of combustion temperature. Due to these fact, indicated mean effective pressure was increased and indicated combustion efficiency was decreased by Carbon dioxide, nitrogen and mixed gas. In case of exhaust emission, hydrocarbon and carbon monoxide was increased by reduction of oxygen concentration in induction air. Especially, partial burning was appeared at lower than about 18 % of oxygen concentration by supplying carbon dioxide. However it was overcome by intake air heating.