• New & Renewable Energy
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• v.9 no.4
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• pp.32-39
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• 2013

A 2-loop waste heat recovery system with Rankine steam cycles for the improvement of fuel efficiency of gasoline vehicles has been investigated. A high temperature loop is used to recover waste heat from exhaust gas and a low temperature loop is used to recover waste heat from cold engine coolant. This paper has dealt with a layout of low temperature loop system, the review of the velocity contours through numerical analysis. According to the result of analysis, the designed heat exchanger. And comparing with flow analysis results, LT Boiler is safe to operation.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.78-84
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• 2012

The purpose of this study is to investigate the performance characteristics of new exhaust heat recovery device for the engine's fast warm-up. In this study, two different interior area designed for prototyping and on the exhaust heat recovery device to evaluate the performance compare the performance characteristics were chosen a better product. A company's product and selected prototype-2 were evaluated and compared the performance. This experiment was conducted under the same conditions. The time from starting to warm-up of engine was measured. As a result, the performance characteristics of the prototype-2 was not higher than that of the A company's product. However, in comparison with base system, prototype-2 of the exhaust heat recovery device discover that the warm-up time was shortened.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.10
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• pp.879-887
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• 2003

Buildings with heating and cooling systems have been increased, since the requirement of thermal comfort for residents is grown. Heating and cooling systems, have been changed from two separate systems to one multi-function system which includes both heating and cooling. Especially, heat pump heating and cooling system has been adopted for general classrooms in schools since education environment improvement project has been launched. This research suggests the best option for the heat pump heating and cooling system in educational buildings through economic assessments for four alternative systems based on electric heat pump (EHP) and gas engine driven heat pump (GHP), which are most widely used for elementary, middle and high schools. The model buildings are in the Y high school which has 24 classes of new construction building, which will be built soon. Annual energy consumption for alternative systems uses BECS 3.10, which can be used for system simulation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.8
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• pp.556-561
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• 2011

In this study, the theoretical maximum power of a heat engine was investigated by sequential Carnot cycle model, for a low-grade heat source of about $100^{\circ}C$. In contrast to conventional approaches, the pattern search algorithm was employed to optimize the two design variables to maximize power. Variations of the maximum power and the optimum values of design variables were investigated for a wide range of UA(overall heat transfer conductance) change. The results show that maximizing heat source utilization does not always maximize power.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.144-152
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• 1996

In the sequential MPI system with one injection for each cycle, engine performance is influenced by the mixture conditions. It can be said that engine performance is improved by being better identical mixture formation conditions for all cylinders. As the fuel injection timing to the intake port effects on the mixture formation conditions and the engine performance, injection timing must be better adjusted to engine requirements. Engine behavior was clearly different depending on the injection time during intake storke. Therefore it was studied that injection timing of fuel effects on the engine performance I. e. combustion stability, COV(imep), A/F excursion, CO,HC emission concentration and fuel consumption. It was found that late intake-synchronous injection was deteriorated the combustion characteristics and performance characteristics, while early intake-synchronous infection resulted in favorable engine behavior.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.55-60
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• 2015

Recent engine development has focused mainly on the improvement of engine efficiency and output emissions. The improvements in efficiency are being made by friction reduction, combustion improvement and thermodynamic cycle modification. Computer simulation has been developed to predict the performance of a spark ignition engine. The effects of various cylinder pressure, heat release, flame temperature, unburned gas temperature, flame properties, laminar burning velocity, turbulence burning velocity, etc. were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion model for a spark ignition engine running with isooctane as a fuel and predicting its behavior.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.92-97
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• 2009

The performance of cooling fan is affected by many peripheral parts, such as radiator, condenser, engine block and etc. Higher power has been requested in more confined automobile engine room. Thus, cooling performance becomes very important to remove the heat generated from the automobile engine more efficiently. In this paper, the performance of cooling fan including effects of engine block is investigated by using a fan tester based on the ASHRAE and the AMCA standards. A flow rate - gap distance curves and a flow rate - engine block constant curves are obtained from this study.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.125-131
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• 2013

This study was carried out to develop a diesel engine for marine propulsion. This marine diesel engine was developed based on a 500Ps vehicle diesel engine. Many main parts, such as the intercooler, radiator, and engine controller were designed for the marine diesel engine. The intercooler was designed to be of sea water cooling type; inlet air is cooled by sea water. Engine coolant is cooled by sea water in the radiator too. The water cooling heat exchanger has high cooling performance. In the cooling system, consists of the intercooler and the radiator, the sea water passes through the intercooler and then the radiator, in sequence. This process is very effective compared to the reverse method in which sea water passes through the radiator and then the intercooler, in sequence. The control performance of the engine controller and the fuel injection rate were improved using an engine speed controller. This system was tested on an engine dynamometer and an exhaust gas analyzer using the marine diesel engine test method. Test results show that the 500Ps marine diesel engine satisfied the IMO NOx regulations; Tier II.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.11
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• pp.915-924
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• 2014

In an aero gas-turbine engine, a surface air-oil heat exchanger (SAOHE) is used to cool the oil system for the gearboxes and electric generators. The SAOHE is installed inside the fan casing of the engine in order to dissipate the heat from the oil system into the bypass duct stream. The purpose of this study was to develop an effective numerical method for designing an SAOHE for an aero gas-turbine engine. A two-dimensional model using a porous medium was developed to evaluate the aero-thermal performance of the fins of the heat exchanger, and a one-dimensional flow and thermal network program was developed to save time and cost in the evaluation of the heat exchanger performance. Using this network program, the pressure drop and heat transfer performance of the heat exchanger were predicted, and the results were compared with two-dimensional computational fluid dynamics results and experiment data for validation.

• THE INDUSTRY AND TECHNOLOGY OF GAS
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• v.5 no.1 s.6
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• pp.28-30
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• 2002