• Proceedings of the KSME Conference
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• 2000.04b
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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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.

• Korean Journal of Agricultural Science
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• v.19 no.1
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• pp.91-96
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• 1992

Diesel engine being used on power tiller has over heating problem while running at the rated power range, The reason for overheating the engine is mainly owing to so small capacity of cooling system. This study was conducted to determine relatively optimum capacity of cooling system for the diesel engine. The results obtained are summarized as follows. 1. The capacity of cooling system for the diesel engine being used in the rural area was not sufficient to cool the engine at the rated power. 2. It is desirable that the cooling water flow rate was $12{\ell}/min$ if we used supplementary pump for increasing the cooling efficiency. 3. As cooling water was circuited $12{\ell}/min$, highest temperature of cooling water was $91^{\circ}C$. This value is within $88^{\circ}C{\pm}5^{\circ}C$ of SAE Standard criterion.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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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.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.83-88
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• 2003

An analytical study was carried out to evaluate the regenerative cooling characteristics in the liquid rocket engine of a 10tf-thrust level using kerosene as a fuel. As a supplementary cooling method, a radiative cooling was applied to the nozzle extension. It was found out from this work that the cooling system with the regenerative and radiation cooling only is not adaptable as a cooling method for the liquid rocket engine of a 10tf-thrust level using kerosene as a fuel for the 2nd stage of the space launch vehicle. So, additional cooling method, curtain cooling was introduced and analyzed. Curtain cooling was very effective to reduce the thermal and thermo-structural instability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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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.