• Journal of the korean Society of Automotive Engineers
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• v.2 no.1
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• pp.9-20
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• 1980

디이젤기관의 냉시동성이 가솔린기관에 비하여 떨어지는 것은 이미 우리가 알고 있는 사실이다. 근년에는 소형트럭, 승용차, 소형건설기계 등의 분야에 있어서도 고속디이젤기관을 널리 사용하게 되었고 앞으로 디이젤연료의 중질화 및 세탄가 저하의 영향 등을 고려할 경우 시동성의 확보는 더욱 중요한 문제로 된다. 시동성에 영향을 미치는 인자 혹은 시동성개선의 방책으로서는 분 무의 착화에 직접 관련되는 것 외에 축전지의 저온특성 혹은 기관의 마찰토오크 등 여러가지에 걸쳐 있으나 이들 중에서 특히 분무의 착화에 직접 관련되는 방책에 관해서는 그것이 시동성에 미치는 영향에만 그치는 것이 아니고 시동개시직후에 있어서 배출가스, 혹은 출력성능 등에 미 치는 영향에 대해서도 함께 고려를 하여야 할 경우가 있다. 본고에 있어서는 냉시동시의 분무의 착화에 대하여 직접 관련하거나 그것을 촉진시킨다고 생각되는 몇개의 인자와 구체적인 방책을 취급하므로써 그것들이 시동성 및 시동직후의 청백연 혹은 출력성능 등에 대하여 미치는 영향에 대해서 기술하며 아래에서 취급되는 시동시의 착화를 촉진하기 위한 실제적인 인자 및 방책은 어느 것이나 기본적으로는 하나의 개념에 집약된다. 즉 그것은 연표와 효소로부터 이루어지는 연소계에 있어서 착화조건을 갖추어야함을 말할 것도 없다.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.144-153
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• 2015

At low temperature, Wax build-up and settling can affect adversely the cold weather performance of the diesel vehicle. In this study, we test the cold properties of diesel by blending ratio of biodiesel, kerosene and WAFI. Also, we test the cold weather performance for diesel vehicle by fuel cold properties. Cold properties of diesel are improved by adding the WAFI, kerosene and get worse by adding the biodiesel. WAFI is effective to improve a cold filter plugging point(CFPP) and Kerosene is effective to improve a cloud point(CP). CFPP and pour point(PP) are related to cold weather performance of diesel vehicle but CP is unrelated. CFPP indicate a limit temperature of vehicle driving possibility.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.165-166
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• 2017

본 논문에서는, 극저온($-32^{\circ}C$)에서 항공기의 초기 시동 및 이의 효율성을 높이기 위한 배터리관리시스템(BMS)의 사전 전기적 특성실험 및 이의 체계적 분석을 실시하였다. 항공기 초기 시동에 사용되는 리튬계열 배터리로서 원통형(cylindrical) 셀을 선택하되, 초기 시동을 위한 순간의 고출력이 가능한 6개의 셀을 수집하였다. 각 셀의 배터리팩(2S2P 및 4S4P) 형태로 구축하고 $-32^{\circ}C$)에서의 저온 방전 실험을 통해 항공기의 초기 시동용 배터리팩에 사용되는 원통형 셀의 선택 및 이의 강인함을 확인할 수 있다. 추가적으로 배터리팩의 설계 및 이의 배터리관리시스템을 위한 초기 정보로서 중요하리라 판단된다.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.144-148
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• 2023

Aircraft battery is the core equipment of an aircraft that supplies engine starting power and emergency power, and it must be charged to ensure sufficient capacity at all times and maintain high reliability to ensure stable power supply. The battery of the T-50 series aircraft is designed to enable the engine to start up to two times in temperatures as low as -18℃ and above. However, intermittent failures in engine starting have been observed during winter. In this paper, we analyze the failure phenomena occurring during low-temperature charging of the battery and improve the charging algorithm based on the analysis and test. Additionally, the results of start simulation tests show that the battery charging defects at low temperatures are resolved, and an improvement in the charging performance is confirmed; thus, validating the effectiveness of the new algorithm.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.7-13
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• 2014

As the interest on the air pollution is gradually rising up at home and abroad, automotive and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward various main issues : whether PM emissions should be regulated for diesel and gasoline vehicles and whether gasoline and LPG powered vehicles can be further neglected from PM emission inventories. Finally, the greenhouse gas ($CO_2$, $CH_4$, $N_2O$) regulation has been discussed including automotive emission regulation. The greenhouse gas and emissions (PM) particle of automotive had many problem that cause of ambient pollution, health effects. This paper discussed the influence of LPG fuel on automotive cold startability and exhaust emissions gas. Also, this paper assessed emission characteristics due to the test temperature. These test temperature were performed by dividing the temperature of the test mode and the lowest local temperature in winter. Through this study, the correlation of cold startability, exhaust emission and greenhouse gas emission was analyzed.

• Journal of IKEEE
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• v.17 no.1
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• pp.63-70
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• 2013

In this paper, we have implemented the performance evaluation system of the unified fuel heater for CRDI diesel engine. If the diesel engine be cold by low temperature in winter, then that makes the waxing materials like a paraffin and is the source of poor engine starting. The unified fuel heater is the barrow meter that estimate the start performance of diesel engine, and be tested by test chamber. The chamber perform the normal temperature, an extremely low temperature, an operating performance in an extremely high temperature, the resistance operation delay time and current operation delay time in setting up test resistance, the bimetal delay time test in temperature variation, the current and resistor test of the composited heater, a heating operation test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2375-2380
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• 2013

In this paper, we have implemented the unified fuel heater and performance evaluation system for diesel cars. In order to strengthen an engine starting of diesel car, we need to assembly the fuel filter and heater. Especially, this assembly fuel heater is very important in winter, it is necessary for heating to operate the diesel engine. The heater for unifying the sensor and heater body can advance the performance of car and reduce the production cost. Finally, the performance test chamber is needed to evaluate the performance of heater.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.1
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• pp.8-18
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• 2012

This paper presents a three-dimensional, transient cold-start polymer electrolyte fuel cell (PEFC) model to numerically evaluate the effects of membrane electrode assembly (MEA) design and cell location in a PEFC stack on PEFC cold start behaviors. The cold-start simulations show that the end cell experiences significant heat loss to the sub-freezing ambient and thus finally cold-start failure due to considerable ice filling in the cathode catalyst layer. On the other hand, the middle cells in the stack successfully start from $-30^{\circ}C$ sub-freezing temperature due to rapid cell temperature rise owing to the efficient use of waste heat generated during the cold-start. In addition, the simulation results clearly indicate that the cathode catalyst layer (CL) composition and thickness have an substantial influence on PEFC cold-start behaviors while membrane thickness has limited effect mainly due to inefficient water absorption and transport capability at subzero temperatures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.711-717
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• 2017

Startability and harmful emissions are the main issues in diesel engine development under cold conditions. The characteristics of combustion with multiple injection were investigated under cold start conditions. For quantitative analysis, the in-chamber pressure profile was measured and combustion visualization using direct imaging was accomplished. With multiple injection, the peak in-chamber pressure and heat release rate were increased compared to single injection. In addition, the period of flame luminosity detection was shortened using multiple injection. Combustion by main injection was improved with an increase in heat released by pilot combustion when the pilot injection quantity was increased. Finally, an increase in injection pressure also showed the possibility of combustion improvement. On the other hand, an increase of in the pilot injection quantity and injection pressure can cause an increase in harmful emissions, such as HC and CO due to wall wetting. Therefore, more sensitive calibration will be needed when applying a multiple injection strategy under cold start conditions.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.9-19
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• 1982

The aim of this study was to improve the startability of the diesel engine at low temperature. The specific objective was to determine the optimum type of precombustion chamber. The eight different types of precombustion chamber and two different types of the cylinder head were designed and tested by $2^7$ factorial experiments with four replications. The lowest starting temperature for first operation, the maximum output, and the specific fuel consumption at full load and overload were checked and analyzed. The results of the study are summarized as follows; 1. The lowest starting temperature was lowered as much as $2.4^{\circ}C$ and the maximum output was increased as much as 0.3 ps with respect to the difference in the relative angle of the main passageway against the piston head from 20 degree to 18 degree. 2. The lowest starting temperature and the maximum out-put were lowered as much as $3.3^{\circ}C$ and 0.3 ps respectively with respect to the difference in the angle of the cylinder head groove from 20 degree to 18 degree. 3. The lowest starting temperature and the maximum out put were lowered as much as $2^{\circ}C$ and 0.2 ps respectively with respect to the difference in the length of the precombustion chamber from 17.5 mm to 15.5mm. 4. There was no significant difference in the startability but the maximum output was increased as much as 0.2 ps with respect to the difference in the diameter of the main passageway from 4.8mm to 4.5mm. 5. The lowest starting temperature was obtained under the condition at 47 degree in the angle of the main passageway and at 18 degree in the angle of the cylinder head groove. The maximum output and the minimum specific fuel consumption was obtained under the condition at 4.5mm in the diameter of the main passageway and at 17.5mm in the length of the precombustion chamber. 6. The angle of the cylinder head groove and the main passageway appeared to the major factors affecting the startability significantly. The interaction between the diameter of the main pass ageway and the length of the precombustion chamber had an significant influence on the maximum output. So it would be recommended to study further on the interaction between two factors mentioned above by expanding their levels. 7. The optimum condition suggested by this study could lower the starting temperature by $6^{\circ}C$ compared to the conventional precombustion chambers.