• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.99-103
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• 2013

In this paper, research on the thermal analysis method is reported for the characterization of heat generation while operating an Interior Permanent Magnet Synchronous Motor (IPMSM) for railway vehicles. Efficient cooling of the heat generated in the IPMSM is important because the excessive heat generated from the winding, core and permanent magnets increases the difficulty of continuously operating an IPMSM over long time periods. Therefore, in this study, in order to analyze the heat generation characteristics of the IPMSM for advanced research in the application of IPMSMs to cooling devices, the heat transfer coefficients for each component of the IPMSM were derived and the thermal equivalent circuit was configured to perform thermal analyses. Finally, the validation of the suggested thermal analysis method was performed through comparison with the heat experimental data of an IPMSM prototype.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.150-157
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• 2008

The main objective of this paper is to investigate the performance characteristics of a $CO_2$ air conditioning system for fuel cell electric vehicles (FCEV). The present air conditioning system for FCEV uses the electrically driven compressor and electrically controlled expansion valve for $CO_2$ as a working fluid. The experimental work has been done with various operating conditions, which are quite matching the actual vehicle's driving conditions such as different compressor speed and high pressure to identify the characteristics of the system. Experimental results show that the cooling capacity and coefficient of performance (COP) were up to 6.3kW and 2.5, respectively. This paper also deals with the development of optimum high pressure control algorithm for the transcritical $CO_2$ cycle to achieve the maximum COP.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.231-235
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• 2015

Bimodal Tram developed by KRRI is driven by a series Hybrid propulsion system which has both the CNG engine, generator and LPB(Lithium Polymer Battery) pack. It has three driving modes; Hybrid mode, Engine mode and Battery mode. Even in case of Battery mode, LPB pack to get enough power to drive the vehicle only by itself onsists of 168 LPB cells(80Ah per lcell), 650V. It is important thing to manage LPB pack in a right way, which will extend the lifetime of LPB cells and operate in the hybrid mode effectively. This paper has shown the development of battery management system(12 BMS, 1 BMS per 14cells) to manage LPB pack which is connected with CAN(Controller Area Network) each other and measure the voltage, current, temperature and also control the cooling fan inside of LPB pack. Using the measured data, BMS can show the SOC(State of Charge), SOH(State of Health) and other status of LPB pack including of the cell balancing.

• Tribology and Lubricants
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• v.32 no.6
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• pp.183-188
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• 2016

Engine oil plays an important role in the mechanical lubrication and cooling of a vehicle engine. Recently, engine development has focused on the adoption of gasoline direct injection (GDI) and turbocharging methodology to achieve high-power and high-speed performance. However, oil dilution is a problem for GDI engines. Oil dilution occurs owing to high-pressure fuel injection into the combustion chamber when the engine is cold. The chemical components of engine oil are currently developed to accommodate gasoline fuel; however, bio-alcohol mixtures have become a recent trend in fuel development. Bio-alcohol fuels are alternatives to fossil fuels that can reduce vehicle emissions levels and greenhouse gas pollution. Therefore, the chemical components of engine oil should be improved to accommodate bio-alcohol fuels. This study employs a 2.0 L turbo-gas direct injection (T-GDI) engine in an experiment that dilutes oil with fuel. The experiment utilizes a variety of fuels, including sub-octane gasoline fuel (E0) and a bio-alcohol fuel mixture (Ethanol E3~E7). The results show that the lowest amount of oil dilution occurs when using E3 fuel. Analyzing the diluted engine oil by measuring density and moisture with respect to kinematic viscosity shows that the lowest values of these parameters occur when testing E3 fuel. The reason is confirmed to influence the vapor pressure of the low concentration bio-alcohol-fuel mixture.

• Journal of Hydrogen and New Energy
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• v.34 no.5
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• pp.447-455
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• 2023

SAE J2601, hydrogen fueling protocols, proposes two charging methods. The first is the table-based fueling protocol, and the second is the MC formula-based fueling protocol. Among them, MC formula-based fueling protocol calculates and supplies the target pressure and pressure ramp rate (PRR) using the pre-cooling temperature of the hydrogen and the physical parameters of the tank in the vehicle. The coefficient of the MC formula for deriving MC varies depending on the physical parameters of the tank in the vehicle. However, most studies use the MC coefficient derived from SAE J2601 as it is, despite the difference in the physical parameters of the tank applied to the study and the tank used to derive the MC coefficient from SAE J2601. In this study, the MC coefficient was derived by applying the hydrogen tank currently used, and the difference with the fueling performance using the MC coefficient proposed in SAE J2601 was verified. In addition, the difference was confirmed by comparing and analyzing the fueling performance of the table-based method currently used in hydrogen fueling stations and the MC formula-based method using MC coefficient derived in this study.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.750-755
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• 2011

The ignition characteristics of liquid rocket engine thrust chambers which have been developed by domestic technology were analyzed. Analysis results showed that low frequency fluctuation appeared in a partial ignition range according to different temperature profiles and vaporous state in the oxidizer manifold with startup sequences. This low frequency fluctuation wasn't developed as a malfunction factor, but this fluctuation is thought to be taken a continuous concern considering interfaces with engine system and launch vehicle.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.72-79
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• 1996

The recent trend of higher output engines with more auxiliary parts is resulting in greater heat generation in the engine compartment. In order to maximize the heat dissipation and eliminate the inefficient flow in the engine compartment, it is necessary to understand the flow field under the hood. In this respect, experimental study as well as numerical analysis should be conducted. The automated measuring system was constructed to obtain three dimensional mean flow data with high accuracy. The measurements have been made on a vehicle with a steady incoming air flow. The result shows that there exists a high degree of non-uniformity in the mean flow velocity at the front of radiator.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.375-378
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• 2010

Hot and high speed plume exhausted during KSLV-I flight test is cooled down by an amount of water ejected from 'gas deflector cooling system' of launch complex to reduce the effects on the launch vehicle and launch complex. In this study, simplified axisymmetric computational calculation with 2-phase is carried out to analysis the water injection effects on flow field.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.235-240
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• 2020

This study evaluated the improvements for circuits of a combat vehicle distribution box to reduce the noise generated in electromagnetic compatibility (EMC) testing. An analysis of the distribution boxes that failed the standard revealed the conducted noise generated from the converter and semiconductor switching elements on the circuit board. The distribution box transfers power from the generator and battery to the cooling system of a combat vehicle to keep turning the air conditioner on and off. Two methods were proposed to overcome this problem: a passive filter was added to the circuit board for the first method, and the converter and switching elements were replaced with the relays for the second method. Both methods were effective in reducing noise, but a greater improvement was obtained from the second method. The second method was applied to a combat vehicle system and was found to be suitable according to the EMC standards.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.29-34
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• 2012

Nowadays, the problem of ETCS terminal in becoming popular gradually is that there is no services except for ETC. Therefore, we need new system that provide many type of additional services at one-terminal. In this paper, we study the additory function of ETCS terminal to afford many type of the vehicle administration beside collection and provider of traffic information. We descrived the method of Eco-driving function beside to save fuel signing instant and mean fuel-efficiency, measurement of section fuel-efficiency on OLED and then brings out the best driving habit in people and to prevent dangerous at the wheel as diagnosing engine oil, cooling water, fan belt, the point of changing consumables, diagnoses to an overheated engine, charges on generator through ECU. The multi-services terminal consist of the vehicle diagnosis module base on OBD-II and ETCS terminal.