• 전기학회논문지
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• 제65권11호
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• pp.1900-1906
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• 2016

Recent energy efficiency policy of green growth for stable power supply is required. Urban transit vehicles is limited to reduce the use of power without reducing the number of runs. Accordingly, when urban rail vehicles is braking, the occurrence of regenerative power is systemically maximized for the purpose of saving energy. As a result when it is braking, the generated power efficiently is used and looking for a way to reduce the electrical energy. In this paper, the brake control system of the Subway Line 3 is analyzed the effect to meet the required regenerative braking produced electricity through minimizing air braking force of service braking.

• 대한전기학회논문지
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• 제39권2호
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• pp.149-156
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• 1990

In DC electric railway systems, the feeding currrnt is not permitted to flow backward in almost all the substations and the pantograph voltages at the regenerating cars rise extremely by the voltage drop of the resistance of the feeder line. In order to prevent the overrise of the pantograph voltage in power regenerating cars, the squeezing circuits for the regenerative current are equipped and this leads to double losses, which are an extra worn-out of the brake-shoes and an ineffective use of regenerative power. In this study, the insertion of resistors in the feeder line system is proposed as a possible method for the effective utilization of the regenerative power in the electric railways. Also it is investigated how the output voltages of substations affect the effective use of regenertive capability. The investigation results show that the energy savings and the reduction of the worn-out of the brake-shoe can be achieved at the same time by the insertion of resistors in the feeder line system.

• 한국소음진동공학회논문집
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• 제26권7호
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• pp.836-843
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• 2016

This study investigates the vibro-acoustic characteristics of an automotive brake drum given free boundaries using the hybrid approach combining numerically obtained structural properties with analytical solution for acoustic radiation. Structural vibrations of the drum are investigated with the finite element method, and modal displacements on the outer surfaces of the drum are idealized as simple mathematical expressions. Based on the expressions, modal sound radiations of the drum are calculated using the Rayleigh integral method. Structural and acoustic responses of the drum for a harmonic excitation are obtained from above results using the modal expansion technique. The results are confirmed with numerical analyses using the boundary element method. Based on these results, it can be concluded that the vibro-acoustic characteristics of a brake drum can be accurately investigated with the process used in this study. Also, many noise and vibration problems in drum brake can be addressed using the procedure proposed in this study.

• 드라이브 ㆍ 컨트롤
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• 제9권1호
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• pp.1-9
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• 2012

Nowadays, various researches about eco-friendly vehicles such as hybrid electric vehicle, fuel cell vehicle and electric vehicle have been actively carried out. Since most of these green cars have electric motors, the regenerative energy technology can be used to improve the fuel economy and the energy efficiency of vehicles. The regenerative brake is an energy recovery mechanism which slows a vehicle by converting its kinetic energy into electric energy, which can be either used immediately or stored until needed. This technology plays a significant role in achieving the high energy usage. However, there are some technical problems for controlling the regenerative braking and the electro-hydraulic brake during switching at transient region. In this paper, the performance simulator for fuel-cell vehicle is developed and transient response characteristics of the regenerative braking system are analyzed in the various driving situations. And the hardware-in-the-loop simulation of electro-hydraulic brake is performed to validate the transient characteristics of the regenerative braking system for fuel-cell electric vehicle.

• 조명전기설비학회논문지
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• 제29권11호
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• pp.82-88
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• 2015

In recent years, numerous studies have attempted to find and explore the auxiliary brake and the oil pressure type and electrical type are mainly used. However, the model proposed here is to self-excited eddy current brake. The advantage of this is it does not require an external power supply and can be produced to reduce the size than others. This self-eddy current brake consists of RLC circuit so resistance, inductance and capacitance value can be considered a fixed value. But, inductance and resistance value changes depending on the shape, temperature and magnetic alteration. Therefore, in this paper, the focal point is characteristic analysis according to the parameter variations. Also, using this result, this paper explains how to estimate the capacitance.

• 에너지공학
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• 제25권2호
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• pp.29-36
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• 2016

도시지역에서는 발전용 디젤엔진의 운영비를 절약하기 위해 천연가스와 디젤을 섞어서 쓰려는 노력을 하고 있다. 본 연구에서는 디젤 연료의 일부를 천연가스로 대체 하였을 때 엔진특성과 천연가스로 대체되는 양에 따라 최적의 밸브 타이밍을 찾아보았다. 1-D 엔진 해석프로그램을 사용하여 19.7리터 발전용 디젤 엔진을 대상으로 모델링하여 연구를 진행하였다. 연구 결과 엔진연료에서 천연가스 비율이 증가할수록 연료소비율(Brake Specific Fuel Consumption, BSFC)는 증가하였고 질소산화물(Brake Specific NOx)는 감소하였다. 추가적으로 흡기밸브 타이밍을 조절할 경우 BSFC가 최대 1%감소하였고 BSNOx의 경우 최대 36%감소하는 효과가 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제16권5호
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• pp.97-110
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• 1992

Rape-seed oil has high viscosity and high rubber content like other vegetable oils. When crude rape-seed oil obtained by a general oil extraction process is used in a diesel engine, automization condition during injection is not good and a large amount of combustion product is doposited in a combustion chamber. The improvement of a diesel engine is required to use rape-seed oil as a diesel engine fuel. In this study, the physical and chemical properties and combustion characteristics of rape-seed oil were investigated. The auxiliary aid was developed to improve automization condition and the effect of the auxiliary injection aid on the performance of a diesel engine was determined. The results are as follows. 1) Oil content of rape-seed is 45%. The exraction rate is 33%. The resuls show higher values compared to those of other vegetable oils. 2) The viscosity of rape-seed oil is 50.8 cSt and nearly 14 times of diesel oil viscosity. 3) The heating value and flash point of rape-seed oil are 9720kcal/Kg and 318$^{\circ}C$, respectively. 4) In case rape-seed oil is used as fuel, brake horse power, specific fuel consumption and brake thermal efficiency are compared to those of diesel oil. The results of rape-seed oil show 3.6%, 12.7% and 3.1% higher values. 5) Particle size of injection fuel with the auxiliary injection aid on the performance of a diesel engine was determined. The results are as follows. 1) Oil content of rape-seed is 45%. The extraction rate is 33%. The results show higher values compared to those of other vegetable oils. 2) The viscosity of rape-seed oil is 50.8 cSt and nearly 14 times of diesel oil viscosity. 3) The heating value and flash point of rape-seed oil are 9720kcal/Kg and 318.deg.C, respectively. 4) In case rape-seed oil is used as fuel, brake horse power, specific fuel consumption and brake thermal efficiency are compared to theose of diesel oil. The results of rape-seed oil show 3.6%, 12.7% and 3.1% higher values. 5) Particle size of injection fuel with the auxiliary injection aids is 100.mu.m smaller than that od injection fuel without the aid. 6) Brake horse power and brake thermal efficiency with the auxiliary injection aid increase 5.07% and 6.07%, respectively. However, specific fuel consumption decreases 3.85% with the auxiliary injection aid.

• 한국항행학회논문지
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• 제17권5호
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• pp.524-544
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• 2013

본 연구에서는 영구 자석형 동기전동기(PMSM)를 축소형의 견인시스템으로 각 전동기를 개별로 제어하는 1C1M방식으로 구축하였다. 전동기를 제동할 때 발생한 회생전력은 모두 활용하고 있으며 전기제동의 사용영역 확대에 발생한 회생전력을 모두 흡수할 수 있는 능력을 가진 가선이라고 가정한다. 영구 자석형 동기전동기(PMSM)의 제동력 확보를 위해 벡터제어 방법과 제어기와 속도 센서를 마미크로프로세서에 제어기를 적용 하였고, 전동기 에너지의 효율적 이용 등 회생 제동에 의한 제동력 확보와 전기 제동으로 정지하는 알고리즘을 적용하여 전동기 관성부하에 대한 시뮬레이션 및 실험결과를 제안하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.776-780
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• 1989

A constant torque dynamometer with associated instrumentation and control functions for the development of friction materials for automotive-type disc brakes, has been developed. Full scale disc pads are subject to a series of intermittent brake applications at a constant rotational speed of the brake disc and constant braking power. This paper gives a description of the dynamometer and an example of results obtained.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.172-181
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• 1999

The brakes employed on commercial vehicles must be able to withstand three types of demanding services which are use-emergency stops from high speed, many repeated stops as in a delivery or bus route, and speed control in mountain descents. Two type of friction brakes are in use ; drum breaks and disc brakes. Drum brakes are of the internally expanding type in which two shoes fitted externally with friction material are forced outward against the inside of a rotating drum on the wheel unit. In this case, the Braking power is produced by the friction force between a drum and a lining, and is converted into heat. In this research an unsteady state heat transfer analysis for drum brake system of heavy truck has been performed by ABAQUS/standard code in the case of single-braking and the repeated braking condition. The temperature histories obtained by the finite Element analysis have been compared with the result calculated by the simplified formulation and the result obtained by the experiment of real vehicle conditions.