• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.213-219
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• 2000

In this work, it has been predicted the thermal performance of the engine cooling system in cases of stationary mode, constant speed mode, city-drive mode, and hill-climb mode by theoretical modeling of each component and numerical analysis. The modelling components are engine, radiator, heater, thermostat, water-pump, and cooling-fan. And also it has been developed the simulation program that can be used in case of design and system configuration changes. The comparison has not been made to verify the results of this work with experimental data, but the overall tendencies were agreed well with those of actual situation in four modes.

• 한국자동차공학회논문집
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• 제23권2호
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• pp.153-160
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• 2015

Hybrid Electric Vehicles(HEVs) have seriously come into prevalence recently as car manufacturers and consumers have become more aware of the environmental and economic problems of conventional vehicles. For the alternative power-train and battery cooling systems in HEVs, an effective thermal management system is required, and many automakers are interested in using Brushless DC(BLDC) motors for cooling fans for the overall traction unit's performance and energy saving capability. This paper presents the development status of BLDC motors as major parts of the power-train, i.e. the engine cooling and battery cooling fans of HEVs. A design that uses BLDC motors for the power-train and each battery cooling fan, is successfully implemented through using electro-magnetic analysis, and prototype BLDC motors are examined. As experimental results, the BLDC motors achieved an efficiency of 85% as engine cooling fans and 72% as a battery thermal management fan motor. The electric cogging noise is significantly reduced by changing the skew of the slot pitch angle and optimizing the magnetic shape.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.10-17
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• 2001

The performance of a radiator is generally determined using a wind tunnel, in which the air velocity is uniform. However, when it is installed in a car, the distribution of the air velocity becomes nonuniform due to front-end openings, cross members, and horns etc., resulting in lower performance. In this study, several underhood flow simulations have been first performed to get flow rates and velocity distributions over the radiator. Secondly heat release rates are calculated by both a performance curve and a radiator model. Finally, using an engine cooling system simulator, radiator-top-tank temperature is predicted and the variations of heat release rate and radiator-top-tank temperature with nonuniformity of air velocity distributions are analyzed. The results show that the current engine cooling model successfully accounts for the nonuniformity effects that should be considered for higher accuracy in predicting engine cooling performance.

• 한국기계가공학회지
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• 제10권5호
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• pp.79-84
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• 2011

Air pollutants from a small marine diesel engine are increasing and the IMO(International Marine Organization) regulation asked for its reduction. In this study, NOx reduction technologies such as improvement of various cooling systems are applied to the small marine diesel engine. The various cooling systems are a intercooler, a heat exchanger for engine coolant, and an exhaust manifold by water cooling. These systems are tested on an engine dynamometer and a exhaust gas analyzer by a marine diesel engine test regulation. Test results are shows that the small marine engine are satisfied the IMO NOx regulations; Tire II.

• 한국기계가공학회지
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• 제11권6호
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• pp.201-207
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• 2012

This study was carried out to improve the design of heat exchanger for small marine diesel engine. As air pollutants emitted from small marine diesel engine become international problem, IMO(International Marine Organization) tried to establish severe regulations for NOx reduction. The formation of NOx is affected by cooling system, for instance, such as intercooler, heat exchanger, exhaust manifold, and therefore cooling systems are one of essential parts for design of small marine diesel engine. In this study, heat exchanger for small marine diesel engine was modeled and simulated using CATIA V5R19 and ANSYS FLUENT V.13. Thermal flow simulation for heat exchanger was performed to find the optimal design. As the results, maximum velocity of engine coolant in shell inside was 9.1m/s and it was confirmed that outlet temperature and temperature drop for engine coolant could be calculated by simulating proportional relations of temperature between engine coolant and sea water.

• 농업과학연구
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• 제19권1호
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• pp.91-96
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• 1992

동력경운기(動力耕耘機) 탑재용(搭載用) 디젤 기관(機關)은 정격출력(定格出力) 범위내(範圍內)에서는 작업시(作業時)에도 냉각수(冷却水) 용량(容量)이 부족(不足)하여 과열(過熱)되고 있다. 따라서, 기관(機關)의 적정(適定)한 냉각수(冷却水) 용량(容量)을 구명(究明)하기 위하여 기존의 기관(機關)에 순경(循璟) 펌프를 설치(設置)하여 냉각수(冷却水) 증가시(增加時)의 성능변화(性能變化)에 대한 실험(實驗)을 실시(實施)하였는데, 그 결과(結果)는 다음과 같다. 1. 동력경운기(動力耕耘機) 탑재용(搭載用) 디젤 기관(機關)의 냉각수(冷却水) 용량(容量)은 정격출력(定格出力) 내(內)에서도 부족(不足)하였다. 2. 기관(機關)에 냉각수(冷却水) 순경(循璟)펌프를 설치(設置)할 경우에 $12{\ell}/min$로 순경(循璟)시키는 것이 적합(適合)하였다. 3. $12{\ell}/min$ 순경시(循璟時) 최고온도(最高溫度)는 $91^{\circ}C$이었으며, 이는 SAE Standard인 $88{\pm}5^{\circ}C$ 이내(以內)였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.196-201
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• 2003

Axial fans are widely used for automotive engine cooling device due to their ability to produce high flow rate to keep engine cool. At the same time, the noise generated by these fans causes one of the most serious problems. Especially, engine cooling fan noise in idle condition of a car is noticeable. Therefore, the high efficient and low-noise fan is seriously needed. When a new fan system is designed, system resistance and non-uniform inflow are the key factors to get the high performance and low noise fan system. In this study, experimental study on the fan and system was carried out and brought a successful result of performance and noise from a designed fan. And through the modification of the fan system, the fan produced more flow rate and became less noisy.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.407-408
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• 2002

This paper presents a split cooling system for a new inline 4-cylinder automotive engine. The split cooling system circulates coolant to the cylinder head and cylinder block separately. The coolant flow in the cylinder block is controlled by a $2^{nd}$ Thermostat installed at the outlet of cylinder block. The $2^{nd}$ thermostat closes when the coolant temperature is low. And this makes the coolant flow in cylinder block nearly stagnant, thereby reducing the coolant-side heat transfer coefficient and raising cylinder bore temperature. The $2^{nd}$ thermostat starts to open when the coolant temperature reaches a specified temperature. The test results on engine dynamometer show improved fuel economy and lower exhaust emission which result from the decrease in friction works and cooling loss. Also, several vehicle tests, with application of the new engine have been performed. Fuel economy improvement of 0.5{\sim}2.0%$ yields from different test modes and details are discussed in this paper.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.83-88
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• 2003

케로신과 액체 산소를 추진제로 하며, 10톤을 설계 추력으로 하는 우주 발사체의 2단용 액 체로켓엔진의 재생 냉각 특성 에 대한 해석적 연구를 수행하였다. 또한 보조적인 냉각 방법으로서 노즐 확장부에는 대기로의 복사 방열에 의한 냉각을 적용하였다. 본 연구를 통해, 케로신을 연료로 하는 10톤 추력의 2단용 액체로켓 엔진에서 재생 냉각과 복사 냉각에 의한 냉각 기구만으로는 냉각 방법으로 적합하지는 않다는 것을 확인하였다. 따라서 새로운 냉각 방법으로서 막냉각 기법이 도입되었으며, 액체로켓엔진의 열적 불안정성을 제거하는데 효과적인 냉각방법임을 알 수 있었다.

• 전기학회논문지
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• 제61권12호
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• pp.1774-1781
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• 2012

There are some efforts to improve the performance of electrical heat pump(EHP) and replace it with an alternative cooling equipment such as gas engine-driven heat pump(GHP), a gas cooling equipment, in order to solve the problem of summer electricity supply through reducing the summer electricity peak. This paper analyzes cost-benefit in accordance with replacement of electrical cooling system by gas cooling system using california standard test and sensitivity analysis of some scenarios.