• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1103-1106
• /
• 2005

The research and development for LPLI system to replace the conventional LPG fuel supply system has been processed with a view to enhancing the environmental status and the efficiency for LPG cars. Part of the small sized cars are under commercialization with the LPLI application already. And yet, most of the technologies are relied upon the advanced countries and as part of the application for large scaled engines, many researches are on the increase. This study shows the technology development to make use of LPLI system for those large engines and reviews the controllers, which were manipulated through experiments for their work, reliability and possibility for commercialization.

• 대한기계학회논문집B
• /
• 제22권11호
• /
• pp.1547-1554
• /
• 1998

The object of this study was to develop an economic assessment program for the optimal design of the cogeneration systems composed of combining engine, generator, waste heat recovery exchanger, absorption chiller, and boiler, etc. The energy demand categorized by electric power, heating, cooling and water supply was determined by statistical data of the existing cogeneration systems. An economic assessment was performed by comparing the total cost of cogeneration system with that of non-cogeneration system. The total cost was evaluated by adding initial investment to operational cost considering efficiency of equipment, cost of equipment, fuel and electricity. To confirm the validity of the developed program, a hotel building with an area of $127,960m^2$ was selected, and the simulated results were compared with the measured data. The difference between the simulated and the measured values for the selected hotel building was approximately 12% for annual electric consumption.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2012년도 춘계학술대회
• /
• pp.378-379
• /
• 2012

현재 에너지 소비가 증가하면서 환경적인 이슈로 전력 산업의 고도화 및 에너지 효율화에 대한 요구가 증가함에 따라 지능형 전력시스템과 같은 전력 IT 산업이 신 성장 동력으로 주목받고 있다. 지능형 전력 시스템을 통해 전력 수요에 따른 공급의 밸런스를 최적화하게 되면 에너지 수입 및 전력 인프라 건설, 운영에 소요되는 막대한 비용을 절감할 수 있고, 안정적으로 전력을 공급할 수 있게 된다. 하지만, 모든 설비 및 장비를 실시간 관리하기 위해서는 인력낭비가 발생할 뿐만 아니라, 응급 상황을 인지하지 못해 전력사고로 이어지는 문제가 발생할 수 있다. 따라서, 본 논문에서는 스마트폰 기반의 원격 제어 및 모니터링 기능을 구비한 지능형 수배전반 통합관리 시스템을 개발하였다. 기존의 수배전반 관리 시스템의 단점을 보완한 본 시스템은 저비용으로 효율성과 안정성을 대폭 향상 시킬 수 있어, 향후 전력 IT 산업의 발전에 크게 도모할 수 있을 것으로 판단된다.

• 한국항행학회논문지
• /
• 제17권6호
• /
• pp.609-615
• /
• 2013

어떤 선박에서도 마찬가지로 적정한 전력의 공급은 매우 중요하며, 육지와 거리가 먼 대양 운항 선박에서는 특히 더욱 중요하다. 이와 같이 운항 중인 선박의 전력 공급 시스템의 효율성과 경제성 측면의 문제를 해결하기 위해서 본 논문에서는 선박에서의 전력공급을 지능적으로 제어하는 전력관리 시스템을 제안한다. 본 설계에서의 전력관리 시스템은 부하전력 감지 시스템, 발전기 제어 시스템, 그리고 전력 모니터링 시스템으로 각각 구성된다. 부하전력 감지 시스템에서는 CT 및 PT 센서를 이용하여 전류와 전력량을 측정하며, 그리고 발전기 제어 시스템에서는 여러 가지 다양한 센서로 부터의 취합정보를 이용하여 주/부 발전기를 On/Off 하게 된다. 마지막으로 모니터링 시스템은 부하 전력 감지 시스템과 발전기 관리 시스템에서 수집된 정보를 사용자가 한눈에 알아볼 수 있게 상태 정보를 출력한다. 본 논문에서 구현된 전력관리 시스템은 실시간 실험을 통해서 설계된 바와 같이 잘 작동하는 것을 확인하였으며, 그리고 공인 인증기관으로부터 KSCIEC61892-1:2012 및 KSCIEC60950-1:2008 인증을 획득하였다.

• 한국자동차공학회논문집
• /
• 제18권1호
• /
• pp.23-30
• /
• 2010

Trends of the automotive market require the application of new engine technologies, which allows for the use of different types of fuel. Since ethanol is a renewable source of energy and it contributes to lower $CO_2$ emissions, ethanol produced from biomass is expected to increase in use as an alternative fuel. It is recognized that for spark ignition (SI) engines ethanol has advantages of high octane number and high combustion speed. In spite of the advantages of ethanol, fuel supply system might be affected by fuel blends with ethanol like a wear and corrosion of electric fuel pumps. So the on-board hydrogen production out of ethanol reforming can be considered as an alternative plan. This paper investigates the influence of ethanol fuel on SI engine performance, thermal efficiency and emissions. The results obtained from experiments have shown that specific fuel consumption has increased by increasing ethanol amount in the blend whereas decreased by the use of hydrogen-enriched gas. The combustion characteristics with hydrogen-enriched gaseous fuel from ethanol reforming are also examined.

• 한국자동차공학회논문집
• /
• 제25권3호
• /
• pp.380-388
• /
• 2017

Wood pyrolysis oil(WPO) has been regarded as an alternative fuel for diesel engines. However, WPO is not feasible for use directly in diesel engines due to its poor fuel quality such as low energy density, high acidity, high viscosity and low cetane number. The most widely used approach to improve WPO fuel quality is to blend WPO with other hydrocarbon fuels that have a higher cetane number. However, WPO and fossil fuels are not usually blended because of their different polarity. Also, clogging and polymerization problems in the fuel supply system can occur when the engine is operated with WPO. Polymerization can be prevented by diluting WPO with other alcohol fuels. However, WPO-alcohol blended fuel does not produce self-ignition. Therefore, additional cetane enhancement to the blended fuel is required to enhance auto-ignitability. In this study, WPO was blended with n-butanol and two cetane enhancements(PEG 400 and 2-EHN) for application to a diesel generator. Experimental results showed that the WPO-butanol blended fuel achieved a very stable engine operation under maximum WPO content of 20 wt%.

• Tribology and Lubricants
• /
• 제33권1호
• /
• pp.23-30
• /
• 2017

The electric controlled marine diesel engine has fuel pump generating the high pressurized fuel for fuel injection to combustion chamber via a common rail. Fuel pump consists of a cam-roller system. Journal bearing installed between a roller and a cam-roller pin is subjected to fluctuating heavy and instant loads by cam lift. First, Kinematic analysis is carried out to predict bearing loads during one cycle acting on the journal bearing. Second, flexible multi-body dynamic analysis and transient elasto-hydrodynamic(EHD) lubrication analysis for journal bearing considering elastic deformation of cam-roller pin, roller and bearing are conducted using AVL EXCITE/PU software to predict lubrication performance. The clearance ratio and journal groove shape providing lubrication oil are important parameter in bearing design having good performance and can be changed easier than other design parameters such as diameter, width, oil supply pressure and bearing material grade. Generally, journal bearing performance is represented by the minimum oil film thickness(MOFT) and peak oil film pressure(POFP). As well as the traditional design parameters(MOFT, POFP), in this study, temperature rise of lubrication oil is also evaluated through the side leakage flow of supplied oil. By the evaluating MOFT, POFP and temperature rise, the optimum bearing clearance ratio is decided.

• 한국추진공학회지
• /
• 제25권3호
• /
• pp.89-100
• /
• 2021

본 논문에서는 메탄엔진 연소시험을 위한 연소시험설비 구축과 예비 시험들을 다루었다. 먼저 액체산소/기체메탄을 추진제로 사용하는 1 kN급 연소기 연소시험설비를 설계 및 구축하였다. 연소시험 전 각 추진제 라인의 수류시험 및 토치 점화기/애프터버너의 점화시험을 통해 연소시험설비의 추진제 공급 안정성, 제어 및 계측시스템 작동, 성공적인 점화를 검증하였다. 마지막으로 예비 연소시험을 수행하여 연소기 시제품의 연소 효율, 열유속, 연소 안정성을 측정하였다. 구축된 연소시험설비는 메탄엔진 연소기 기초연구 및 개발에 유용하게 활용될 예정이다.

• 농업과학연구
• /
• 제49권4호
• /
• pp.845-855
• /
• 2022

The purpose of this study is to develop a self-propelled underground crop harvester and its performance was evaluated by measuring the load during actual potato harvesting operations. This study was conducted at a constant working speed of 1 km·h^-1. A load measurement system was installed to measure the actual load and the required working power was analyzed. A hydraulic pressure sensor was also installed to measure the hydraulic pressure. The required hydraulic power was calculated using the hydraulic pressure and flow rate. The results showed that the engine speed, torque, and power during harvesting operation were in the range of 845 - 1,423 rpm, 95 - 228 Nm, and 9 - 31 kW, respectively. Traction power, excluding the hydraulic pump of the tractor and power take-off (PTO) output, was in the range of 9 - 28 kW, and it was confirmed that it occupies a ratio of 16.2 to 50% of the engine rated output. The engine can supply the minimum required traction power to move the vehicle. This means that the engine used in this study could be down-sized to be suitable for an underground crop harvester. In this study, the gear stages of the tractor were not considered. This research thus shows the possibility of developing a self-propelled underground crop harvester.

• 한국가스학회지
• /
• 제13권4호
• /
• pp.1-7
• /
• 2009

최근 연료경제성 및 강화되는 배출가스 규제를 만족하기 위하여 대체연료의 하나인 LPG에 대한 수요가 증가하고 있다. 현재 LPG 차량에 적용되고 있는 제3세대 LPG 연료공급방식인 LPLi(Liquid Phase LPG Injection) 시스템은 가솔린 차량과 비교하여 배출가스는 적게 배출하면서 동등한 출력을 낼 수 있게 하는 핵심 기술이다. LPG 연료를 고압의 액상 상태로 공급하기 위해서는 LPG 펌프가 필요하다. 연료펌프의 성능을 저하 시킬 수 있는 연료 내 불순물을 제거하기 위하여 연료펌프에는 연료필터가 장착되어 있으며 장착되는 연료필터의 종류에 따라서 연료펌프의 성능도 변하게 된다. 본 연구에서는 임펠라 방식을 채택한 LPG 연료펌프에서 극세사, 이중메쉬, 외장형 필터의 세 가지 필터에서 부하별 토출성능 및 효율을 파악하였으며 온도 변화에 따른 펌프유량 변화를 측정하였다.