• 한국분무공학회지
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• 제23권1호
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• pp.1-8
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• 2018

In this study, the effects of variation in cam phasing and valve lift of exhaust valves by using Cam-in-Cam system on combustion and emission characteristics for diesel engine were investigated under GT-POWER simulation environment. This paper showed analytic result of combustion characteristics and diesel exhaust valve's control with GT-Power 1-D detail model. As a result, it was found that volumetric efficiency and IMEP were decreased as the exhaust valve opening and closing timing is advanced due to its internal EGR effects. Also, it was found that NOx emission were decreased as EVC timing was retarded. These show that the retarding the exhaust valve closing and opening while keeping the duration at constant can be effective for controlling AFR and mixing rate in diffusion combustion of diesel engine.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.177-181
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• 1996

A fundamental study for the production of an internal combustion engine piston by forging is performed through UBET(Upper Bound Elemental Technique) analysis and experiments. In UBET analysis, an optimal preform of the aluminum piston is predicted and the results are compared with the experimental results. The internal flow pattern and and the forging loads according to the different friction condition are investigated.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.380-386
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• 2020

This paper represents an analysis of the economic impact of firing natural gas/diesel and natural gas/by-product oil mixtures in diesel engine power plants. The objects of analysis is a power plant with electricity generation capacity (300 kW). Using performance data of original diesel engines, the fuel consumption characteristics of the duel fuel engines were simulated. Then, economic assessment was carried out using the performance data and the net present value method. A special focus was given to the evaluation of fuel cost saving when firing natural gas/diesel and natural gas/by-product oil mixtures instead of the pure diesel firing case. Analyses were performed by assuming fuel price changes in the market as well as by using current prices. The analysis results showed that co-firing of natural gas/diesel and natural gas/by-product oil would provide considerable fuel cost saving, leading to meaningful economic benefits.

• 한국자동차공학회논문집
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• 제21권3호
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• pp.105-112
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• 2013

In this paper, EV (Electric Vehicle) and ICE (Internal Combustion Engine) vehicle simulators are developed to compare maximum driving range of EV and ICE vehicle according to different driving patterns. And, simulations are performed for fourteen constant velocity cases (20, 30, 40, ${\ldots}$, 150 km/h) and four different driving cycles. From the simulation results of constant velocity, it is found that the decreasing rate of maximum driving range for EV is larger than the one for ICE as both the vehicle velocity and the driving power increase. It is because the battery efficiency of EV decreases as both the velocity and the driving power increase, whereas the engine and transmission efficiencies of ICE vehicle increase. From the results of four driving cycle simulation, the maximum driving range of EV is shown to decrease by 50% if the average driving power of driving cycle increases from 10 to 20kW. It is because the battery efficiency decreases as the driving power increases. In contrast, the maximum driving range of ICE vehicle also increases as the average driving power of driving cycle increases. It is because the engine and transmission efficiencies also increase as the driving power increases.

• 한국가스학회지
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• 제25권5호
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• pp.52-56
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• 2021

친환경적인 환경과 자동차산업의 발달로 내연기관자동차에서 완전연소를 통해 열효율을 높이고 배기가스를 점감하기 위한 연구를 활발하게 진행하고 있다. 특히 휘발유의 휘발성과 연소특성에 대한 이해로 엔진의 부하와 출력을 높이기 위한 연구가 진행되고, 경유 연료의 증류 및 연소특성을 토대로 매연이나 유해가스 저감과 최적의 효율을 구현하기 위한 연구가 진행 중이다. 따라서 본 연구에서는 한국 산업규격의 석유제품 증류시험방법에 대한 KS M ISO 3045의 내용을 토대로 국내에서 시판되고 사용되는 정유사 4사의 휘발유와 경유를 기반으로 증류실험을 진행하였다. 증류실험으로 증류량에 따른 증류온도와의 상관관계를 확인하고 증류된 연료의 비교를 통해 증류특성에 대한 분석을 실시하여 시험기준에 부합하는지에 대한 적합성을 확인하였다.

• 한국추진공학회지
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• 제19권5호
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• pp.22-30
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• 2015

개방형 사이클의 액체로켓엔진에서는 추진제 중 일부를 연소시켜 터빈 구동용 가스를 생성시키는 가스발생기가 사용되며, 개방형 사이클 액체로켓엔진의 주요 구성품으로서 가스발생기 자체의 연소성능 및 특성을 파악하기 위한 연소시험이 요구된다. 하지만, 가스발생기에서 생성된 연소가스는 터빈 매니폴드의 터빈 노즐에서 질식이 이루어지기 때문에 가스발생기뿐만 아니라 터빈 매니폴드 내부 부피를 고려해야만 가스발생기의 연소 성능 및 특성, 그리고 음향 특성을 정확히 파악할 수 있다. 따라서, 본 논문에서는 터빈 매니폴드 모사장치를 이용한 가스발생기 연소시험 결과를 기술하고 가스발생기 단독 연소시험 결과를 이용한 특성 예측을 설명한다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.232-239
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• 1999

Generally quantity of supply oil for piston ring lubrication in an internal combustion engine may be insufficient to fill the entire volume formed in the clearance between piston ring and cylinder liner. Thus oil starvation condition should be considered for the analysis of piston ring lubrication. In order to reasonably estimate amount of oil left on the cylinder liner, adequate boundary condition should be adapted for the analysis of ring pack lubrication. In this analysis of ring pack lubrication of an internal combustion engine, oil starvation and open-end boundary conditions are considered at inlet and outlet of piston rings. It is revealed that piston rings are operated under oil starvation in most operating cycle and the result with these conditions are quite different from that with fully-flooded assumption.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.114-120
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• 2000

EHL analysis of connecting rod bearing is proposed which includes effects of temperature variation in lubrication film. Lubrication film temperature is treated as a time-dependent, two-dimensional variable which is averaged over the film thickness, while connecting rod big end temperature is assumed to be time-independent and three-dimensional. It is assumed that a portion of the heat generated by viscous dissipation in the lubrication Him is absorbed by the film itself, and the remainder flows into the bearing surface. Mass-conserving cavitation algorithm is applied and the effect of variable viscosity is included to solve the Reynolds equation. Simulation results of the connecting rod bearing of internal combustion engine are presented. It is shown that the temperature variation has remarkable effects on the bearing performance. It is concluded that the EHL analysis considering effects of the temperature variation is strongly recommended to predict the bearing performance of connecting rod big end On internal combustion engine.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.491-502
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• 1997

This paper describes a theoretical and exprimental investigation of the pressure - time histories of some basic internal combustion engine exhaust systems. The program package is utilized the method of characteristics to solve the general equations of one - dimensional unsteady gas flow. This analysis is then combined with boundary models, based on quasi - steady flow approach, to give a complete treatment of the flow behavior in the exhaust system. Using a rotary valve exhaust simulator, experimental pressure - time histories were obtained. The predictions are com¬pared with measured results and show a high degree of correlation in amplitude and phasing.

• Tribology and Lubricants
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• 제15권3호
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• pp.233-239
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• 1999

Generally quantity of supply oil for piston ring lubrication in an internal combustion engine may be insufficient to fill the entire volume formed in the clearance between piston ring and cylinder liner. Thus oil starvation condition should be considered for the analysis of piston ring lubrication. In order to reasonably estimate amount of oil left on the cylinder liner, adequate boundary condition should be adapted for the analysis of ring pack lubrication. In this analysis of ring pack lubrication of an internal combustion engine, oil starvation and open-end boundary conditions are considered at inlet and outlet of piston rings. It is revealed that piston rings are operated under oil starvation in most operating cycle and the result with these conditions are quite different from that with fully-flooded assumption.