• 한국자동차공학회논문집
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• 제14권1호
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• pp.153-158
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• 2006

To optimize the combustion system in a HSDI diesel engine, a new analysis technology was developed. The in-cylinder 3-D combustion analysis was carried out by the modified KIVA-3V, and the spray characteristics for the high pressure injection system were analyzed by HYDSIM. The combustion design parameters were optimized by coupling the KIVA-3V and the iSIGHT. The optimization procedure consists of 3 steps. The $1^{st}$ step is the sampling method by the Design of Experiment(DOE), the $2^{nd}$ step is the approximation using the Neural Network method, and the $3^{rd}$ step is the optimization using the Genetic Algorithm. The developed procedures have been approved as very effective and reliable, and the computational results agree well with the experimental data. The analysis results show that the optimized combustion system in a HSDI diesel engine is capable of reducing NOx and Soot emissions simultaneously keeping a same level of the fuel consumption(BSFC).

• 한국자동차공학회논문집
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• 제14권1호
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• pp.138-143
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• 2006

Modification of injector, oil ring tension reduction and oil pump rotor re-matching with optimization of relevant engine control parameters could drive fuel consumption reduction of HSDI diesel engine. A 5 holes injector was replaced with a 6 holes with smaller nozzle hole diameter and 1.5 k factor, and evaluated in a view of fuel economy and emission trade-offs. With introducing smaller nozzle hole diameter injector, PM(Particulate Matter) was drastically decreased for low engine load and low engine rpm. Modification of oil pump and oil ring was to reduce mechanical friction and be proved to better fuel economy. Optimization of engine operating conditions was a great help for the low fuel consumption. Influence of the engine operating parameters· including pilot quantity, pilot interval, air mass and main injection timing on fuel economy, smoke and NOx has been evaluated with 14 points extracted from NEDC(New European Driving Cycle) cycle. The fuel consumption was proved to $7\%$ improvement on an engine bench and $3.7\%$ with a vehicle.

• 오토저널
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• 제23권1호
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• pp.43-53
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• 2001

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3300-3305
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• 2007

Ignition delay of second injection of HSDI diesel engine was usually much shorter than that of first injection. It is due to the interaction between radicals generated during the combustion process, and mixed gas of second injection. In this paper, To analyze combustion phenomena of multiple injection mode in HSDI diesel engine effectively, two-dimensional flamelet combustion model was modified. To reduce calculation time, two-dimensional flamelet equations were only applied near stoichiometric region. If this region was ignited, species and temperature of other region were changed to the steady-state solutions of one dimensional flamelet equations. By this method calculation time for solving flamelet equations was reduced to 20 percents, thought the results were almost same. Modified flamelet combustion model was coupled to commercial CFD code interactively using user subroutine.

• 에너지공학
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• 제10권3호
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• pp.177-182
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• 2001

본 연구는 경유승용차(HSDI 경유엔진) 도입에 대해 소비자 측면, 사회적 측면의 경제적 효과를 분석하고자 하였다. 먼저, 생애비용을 고려한 소비자 경제성분석 결과 승용차 수명 10년, 연간 평균 주행거리를 20.000km로 가정할 때 승용차 1대당 연료비 절감액은 13,836천원으로 추정된다. 사회적 편익은 평균 주행거리 20,000km 기준 경유승용차 관매 10% 증가 전제시 휘발유 승용차 대비 2002년부터 이익이 실현되기 시작하여 2010년에 1,541억원의 편익이 발생하는 것으로 추산된다. 사회적 누적편익은 판매량 10% 증가 가정시 20,000km 주행시 2010년까지 6,368억원의 편익이 발생할 것으로 보인다.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.40-57
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• 2004

The effects of triple (pilot, main and after) injection on combustion and emission characteristics in a HSDI (High-Speed Direct Injection) diesel engine were investigated using a single-cylinder optical diesel engine equipped with a common-rail injection system. The pilot injection affected the spray and combustion evolution of the following main injection. It was found that the pilot injection reduced the ignition delay, which led to lowered NOx (Nitric Oxides) level, and increased IMEP (Indicated Mean Effective Pressure) due to slow combustion pace during an expansion stroke. The after-injection was shown to be effective in reducing PM (Particulate Matter) even when a small amount of fuel was added. The results suggest that a proper combination of individual injection strategy could bring about a good synergetic effect on engine performance and emission.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2005년도 한국가시화정보학회 연소/내연기관 부문 학술강연회
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• pp.3-57
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• 2005

왕복동 내연기관에서의 연소 및 배기가스 생성은 복잡한 3차원 영역 내에서 난류 유동, 분무, 화학반응, 열전달, 경계층 현상이 상호 연계되어 있는 매우 복합적인 과정이다. 특히 난류 연소 현상은 기관의 효율을 결정하는 연소 속도와 pollutant의 배출 농도를 결정하는 핵심 요소로서 관련 모델과 수치 해법에 대해 학술적, 공학적 측면에서 세계적으로 활발한 연구가 이루어지고 있다. 이를 위해 수행되는 다양한 실험 측정과 수치 해법을 통해 얻어지는 3차원 과도 상태의 방대한 스칼라량과 벡터량에 대한 정보를 효율적으로 처리하기 위해서는 적절한 가시화 과정이 필수적이다. 여기서는 최근 다양한 엔진 타입들에 대한 응용 사례와 함께 난류 연소 모델링을 위한 새로운 접근법으로서 조건평균법(conditional averaging)에 대해 간략히 소개하고자 한다. 난류예혼합연소에서의 난류화염속도에 대한 DNS와 영역조건평균에 기초한 예측식의 검증, 천연가스 jet의 자발화 지연기간, n-heptane jet의 자발화 진행 과정, HSDI 엔진, HCCI 엔진, CNG 엔진, LPG 분무 및 엔진, GDI 엔진 등에 대한 연구 결과들은 정보 가시화의 한 사례가 될 수 있을 것으로 생각된다.

• 대한기계학회논문집B
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• 제25권2호
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• pp.187-194
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• 2001

Spray impingement and fuel film formation models were developed and incorporated into the computational fluid dynamics code. STAR-CD. The spray/wall interaction process was modeled by considering the change of behaviour with surface temperature conditions and the fuel film formation. We divided the behaviour of fuel droplets after impingement into rebound, spread and splash using the Weber number and the parameter K. The Spray impingement model accounts for mass conservation, energy conservation and heat transfer to the impinging droplets. The fuel film formation model was developed by integrating the continuity, Navier-Stokes and energy equations along the direction of fuel film thickness. Validation of the models was conducted using previous diesel spray experimental data and the present experimental results for the gasoline spray impingement. In all the cases, the prediction compared reasonably well with the experimental results. The spray impingement and fuel film formation models have been applied to the spray/wall impingement in high speed direct injection diesel engines.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2003년도 하계 학술대회 논문집
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• pp.407-412
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• 2003

지구환경보존이 세계적인 과제로 되어있는 오늘날 디젤엔진으로부터 배출되는 배기배출물에 대한 문제가 대두되고 있으며, 미국의 캘리포니아주(CARB)에 있어서는 세계최초로 농업기계용 엔진을 포함한 운송용 엔진에 대하여 엄한 배기가스 규제법안을 세워 시행중에 있다. 또한 전미, 유럽 및 일본에 동일한 검사가 이루어지고 있는 실정이다. 따라서, 디젤엔진으로서 문제가 되고 있는 배기성분인 NOx와 파라큘레이트(PM)에 대한 저감대책으로 최근 고압분사(HSDI), EGR 및 후처리(De-NOx) 촉매등의 연구가 시행되고 있으며, 전망이 기대되어지고 있다. 그러나 경제성, 내구성, 제품의 크기, 차량의 중량증가 등이 과제로 남겨지고 있다(유강택 외 1997). (중략)

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1704-1709
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• 2004

New reduced chemical kinetic mechanism for prediction of autoignition process of HSDI diesel engine was investigated. For precise prediction of the ignition characteristics of diesel fuel, mechanism coefficients were fitted by the experimental results of ignition delay of diesel spray in a constant volume vessel. Ignition delay of diesel engine on various operation condition was calculated based on the new reduced chemical mechanism. The calculation results agreed well with experimental data.