• 한국자동차공학회논문집
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• 제17권5호
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• pp.31-38
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• 2009

Supercharging system was adopted to investigate the influence of boost pressure on operating range and exhaust emissions by using a supercharger at low temperature diesel combustion (LTC) condition in a 5-cylinder 2.7 L direct injection diesel engine. The experimental parameters such as injection quantity, injection timing, injection pressure and exhaust gas recirculation (EGR) rate were varied to find maximum operating range in LTC condition. As a result of adopting increased boost pressure in LTC, wider operating range was achieved compared with naturally aspirated condition due to increased mixing intensity. Increased boost pressure resulted in lower hydrocarbon (HC) and carbon monoxide (CO) emissions due to increased swirl rate and mixing intensity, which induced complete combustion. Moreover, increased boost pressure in LTC resulted in much lower soot emissions compared with high speed direct injection (HSDI) condition.

• 대한기계학회논문집B
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• 제33권4호
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• pp.248-254
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• 2009

The HCCI engine is a next generation engine, with high efficiency and low emissions. The engine may be an alternative to SI and DI engines; however, a pressure rise rate is a major limitation for high load range and power reduction. Recently, we were able to reduce the pressure rise rate using thermal stratification. Nevertheless, this was insufficient to produce high power. In this study, the reduction of the pressure rise rate using thermal stratification was confirmed and the HCCI engine power was increased using the boost pressure. The rate and engine power were produced by CHEMKIN and modified SENKIN. As a result of increasing the boost pressure, a higher IMEP was attained while the pressure rise rate increased only slightly in the HCCI with thermal stratification.

• 한국생산제조학회지
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• 제9권1호
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• pp.53-59
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• 2000

Recently air pollution is increased according to increase of vehicle. So many countries are studying about compressed natural gas engine. Research on the development of CNG dedicated engine that has important meaning both as a clean fuel and an alterna-tive energy to reduce the exhaust emission from diesel engine are actively going on these days. In this study the character-istics of CNG engine was investigated and the engine performance experimented by changing the parameters such as boost pressure. The CNG engine performance and exhaust emission were measured by engine performance mode at maximum load condition with increasing the rpm in the range of 1,000-2,200rpm. The exhaust emission was also measured at D-13 mode and compared to the emission regulation.

• 오토저널
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• 제11권2호
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• pp.41-54
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• 1989

In this study, steady state heat conduction problems of the cylinder block of turbocharged gasoline engine were solved by the boundary element method. Surface of the cylinder block was divided by the triangular cells with constant potential. Temperature distribution, effective heat transfer coefficient of the cylinder block were investigated with variation of equivalence ratio, engine speed and boost pressure. The results show that maximum temperature of cylinder block increase rapidly with increasing engine speed and boost pressure. The monolithic structure of cylinder block results in sever inhomogeneity of inner wall temperature at the high engine speed and boost pressure.

• 대한기계학회논문집B
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• 제38권6호
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• pp.451-464
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• 2014

본 연구에서는 HCCI엔진의 과급조건에서 EGR의 영향에 대하여 수치해석적인 방법으로 연구하였다. 수치해석은 CHEMKIN-PRO에 있는 single-zone model을 사용하였고 연료로는 N-heptnae, Iso-octane 그리고 PRF50을 사용하였다. 사용된 연료의 화학반응 매커니즘과 열역학적 변수들은 Lawrence Livermore National Laboratory(LLNL)의 모델을 사용하였다. 연소상의 변화는 열효율에 큰 영향을 미치게 되므로 이영향을 배제하기 위해 본 연구에서는 CA50을 $365^{\circ}CA$($5^{\circ}CA$ aTDC)로 일정하게 고정하였다. 연구결과 EGR의 영향으로 줄어든 산소의 영향에 의해 저온산화반응과 NTC, 고온산화반응이 모두 약화되고 열발생률이 감소하는 것을 확인할 수 있었다. 과급과 EGR을 함께 사용하게 되면 과급에 의해 증가한 산소량과 연료의 영향으로 인해 연소가 강화되어 저온산화반응, NTC, 고온산화반응이 강화되고 열 발생률이 증가하는 것을 확인할 수 있었다. EGR만을 사용하는 경우 IMEP가 감소하는 경향을 나타내지만 과급과 EGR을 함께 사용하는 경우 과급의 영향으로 인해 IMEP가 크게 증가하여 낮은 압력상승률과 높은 출력을 함께 얻을 수 있는 것을 확인하였다.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.65-72
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• 2002

The closed cycle diesel system is operated in closed circuit system where there is non air breathing with working fluid consists of combination of oxygen, argon and recycled exhaust gas far obtaining underwater or underground power sources. Experimental apparatus using the MTU8V183SE92 high pressurized engine adapted for closed cycle running, capable of operating at the system pressure of maximum 5 bar is constructed with ACAP as data acquisition system in order to operate equally in the open cycle in surface or the closed cycle in submerged conditions. The general features and the characteristics of combustion of HP(high pressure) diesel engine, specially designed and manufactured only for CCDE, are investigated. The test results of performance of HP diesel engine in closed cycle system are presented with respect to power and boost pressure and compared with those of low pressure diesel engine. The oxygen concentration and specific heat ratio are investigated with its deviation

• 한국자동차공학회논문집
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• 제23권3호
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• pp.299-306
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• 2015

Turbocharged gasoline direct injection engine is one of promising technologies in the automotive industry. However, reduction in turbo-lag under transient operation is one of important challenging points to improve drivability. Engine transient performance was investigated in a 4-cylinder 2.0 L turbo-gasoline direct injection (T-GDI) engine using Inconel and TiAl (Titanium Aluminide alloy) turbine wheel turbochargers. The TiAl turbocharger performed superior transient boost pressure and torque rises under various engine transient operation conditions. These were mainly due to lower turbine rotational inertia of TiAl turbocharger. The Maximum boost pressure and torque build up were founded in 1500 rpm and 2000 rpm, instant load change from 20% to 100% of pedal position.

• 전력전자학회논문지
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• 제14권1호
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• pp.72-81
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• 2009

본 논문에서는 대기압 플라즈마 발생용 정현파펄스형 교류 전원 장치에 대한 연구를 진행하였다. 정현파펄스형 전원장치는 기존의 LC공진을 이용한 교류 전원장치보다 높은 dv/dt를 갖게 되므로 안정적인 플라즈마 공급이 가능하며 펄스형에 비해 고조파 노이즈가 적고, 정전류 턴온-영전압 턴오프 형태로 동작하므로 매우 높은 효율을 갖는다. 또한 플라즈마 점화 기능을 강화하고 안정적인 전압제어를 위해 3상 부스트형 컨버터를 입력단에 사용하여 입력 역률이 매우 높은 시스템을 구성할 수 있다. 실험실 수준의 10kW부하시설을 사용하여 본 연구의 결과를 입증하였다.

• 대한기계학회논문집B
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• 제34권6호
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• pp.615-622
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• 2010

본 연구에서는 중형 직분식 선박용 엔진의 성능 및 NOx 배출물 예측을 위한 0-D multi-zone 분무 연소 모델이 개발되었다. 모델은 상용 1-D 사이클 해석 프로그램 (Boost)와 연동할 수 있도록 개발되었으며, 흡배기 시스템을 포함한 엔진 전체에 대한 동시 해석이 가능하였다. 연소 모델은 Fortran90 으로 개발되었으며, AVL 에서 제공된 'user defined high pressure cycle (UDHPC) interface'를 통해 Boost 와 연동되었다. 두 가지의 인젝터(8 홀, 10 홀)에 대해 두 가지 부하에서 해석을 수행하였으며, 해석 결과는 실제 엔진의 성능 실험 결과를 잘 추종하였다.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.8-14
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• 2004

본 논문에서는 승압형 컨버터를 사용한 400(W) 고압나트륨 램프용 전자식 안정기 역률 보상회로를 설계하였다. 제안된 승압형 컨버터 회로에서 역률 보상 소자의 값을 이론적으로 계산하고 IsSPICE를 이용하여 시뮬레이션을 수행하였으며, 시뮬레이션 결과를 검증하기 위해 설계방법에 따라 전자식 안정기를 제작하여 실험하였다. 실험에 의한 역률 보상회로의 제반특성은 시뮬레이션 결과와 거의 일치하였다. 실험결과 출력 400(W)에서 역률 99.3(%)의 성과를 나타내었다.