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정경석,C.Arcoumanis,J.H.Whitelaw 한국자동차공학회 1992 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1992 No.11
The flow in the cylinder of purpose-built Hydra optical engine, based on the Ford 1. 8L HSDI diesel, was investigated using laser Doppler velocimetry (LDV) during induction and compression. The flow was quantified in terms of ensemble-averaged axial and swirl velocities, normalized by the mean piston speed(Vp= 2. 733m/sec), at a plane located l2mm from the cylinder head and corresponding to the mid-plane of the diametrically-opposed quartz windows at an engine speed of 1000rpm
[가솔린엔진부문] 직접 분사 CNG 엔진의 연소 및 배출가스 특성
김종우(Jongwoo Kim),C.Arcoumanis 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Natural gas has been considered as one of the most promising alternative fuels for transportation due to its ability to reduce regulated pollutants and its abundance. However, since its combustion and emission characteristics are quite different from conventional liquid fuels such as gasoline and diesel, further investigation is required. The objective of this work was to examine the characteristics of combustion and the reduction of exhaust emissions from direct injection of compressed natural gas (CNG) in a purpose-built, multi-cylinder spark-ignition engine equipped with a four-valve cylinder head and offering optical access through an extended piston and windows in the liner. In addition, CNG jet development was examined in a constant-volume chamber using Schlieren photography in terms of jet cone angle and tip penetration. Baseline testing was performed with manifold injection of CNG, using direct imaging of the propagating flame with simultaneous measurement of in-cylinder pressure and exhaust emissions. For investigation of the effect of charge stratification induced through direct in-cylinder injection of CNG, a<br/> sampling probe was incorporated into the spark plug for measuring the local hydrocarbon levels at the time of ignition. Overall, the results revealed that direct injection of CNG increases the volumetric efficiency of the engine relative to manifold injection and allows enhanced in-cylinder flow motion and charge stratification at the time of ignition. The resulting faster flame propagation and reduced cycle-to-cycle variations makes the CNG engine comparable in combustion performance with conventional gasoline-fuelled engines, while at the same time offering the potential for reduced NOx emissions as a result of the engine's leaner operating limit<br/>
EFFECTS OF INTAKE FLOW ON THE SPRAY STRUCTURE OF A MULTI-HOLE INJECTOR IN A DISI ENGINE
김성수,J. M. NOURI,Y. YAN,C. ARCOUMANIS 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.3
The spray characteristics of a 6-hole injector were examined in a single cylinder optical direct injection spark ignition engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure, and coolant temperature were investigated using the 2-dimensional Mie scattering technique. It was confirmed that the in-cylinder charge motion played a major role in the fuel spray distribution during the induction stroke while injection timing had to be carefully considered at high injection pressures during the compression stroke to prevent spray impingement on the piston.
Eulerian-Lagrangian 다상 유동해석법에 의한 피에조 인젝터의 노즐 내부 비정상 캐비테이션 유동해석
이진욱 ( Jin Wook Lee ),민경덕 ( Kyung Duk Min ),강건용 ( Kern Yong Kang ),( M. Gavaises ),( C. Arcoumanis ) 한국분무공학회 2004 한국액체미립화학회지 Vol.9 No.4
N/A This study describes the analysis results of unsteady cavitating flows behavior inside nozzle of the prototype piezo-driven injector. This piezo-driven injector has been recognised as one of the next generation diesel injector due to a higher driven efficiency than the conventional solenoid-driven injector. The three dimensional geometry model along the central cross-section regarding of one injection hole has been used to simulate the cavitating flows for injection time by at fully transient simulation with cavitation model. The cavitation model incorporates many of the fundamental physical processes assumed to take place in cavitating flows. The simulations performed were both fully transient and `pseudo` steady state, even if under steady state boundary conditions. We could analyze the effect the pressure drop to the sudden acceleration of fuel, which is due to the fastest response of needle, on the degree of cavitation existed in piezo-driven injector nozzle