• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.3
• /
• pp.112-118
• /
• 2006

In this paper, we presented experimental data of the strength of the electro-magnetic waves in the engine room of automobiles. Measured frequency ranges are $145{\sim}380MHz$ and $844{\sim}1044MHz$. Experimental studies are conducted by measuring the radiated power of the frequency spectrum for above frequency bands. The $\lambda/2$ dipoles used for measurement are fabricated to comply with the COMMISSION DIRECTIVE 95/54EC. Experimental results confirm that the level of radiated power in the engine room at idling rpm is about 3dB higher than that of 1500rpm.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.9 no.1
• /
• pp.46-52
• /
• 2005

A propeller as a propulsion system has been redesigned to improve performance of a target drone. The vortex theory has been applied for the propeller design method. Design variables have been the chord length along the direction of blade radius, the change of blade radius, and the geometric angle of the blade. The existing propeller has been redesigned and modified considering engine RPM change to get the improved thrust at both low and high speeds.

• Proceedings of the KIPE Conference
• /
• 2015.07a
• /
• pp.143-144
• /
• 2015

전기추진선박은 디젤엔진과 프로펠러의 회전축이 기계적으로 연결된 기존의 선박과 달리 엔진의 기계적 에너지를 전기 에너지로 변환하여 전동기 회전을 통해 추진력을 얻는 선박으로서 시추선, 군함, OSV(Offshore Support Vessel)등 높은 조종성능이 요구되는 선종에 주로 적용되고 있다. 이러한 선종은 추진력을 얻는데 가장 큰 전력을 사용하므로 날씨에 따른 전력부하량의 변동이 크다. 본 논문에서는 슈퍼커패시터로 구성된 전력버퍼모듈을 이용하여 전기추진선박의 효율적인 전력 운용 전략을 제안한다. 추진전동기의 VFD(Variable Frequency Drive)의 직류단을 전력버퍼모듈로 통합하여 각 전동기의 보조전력으로 활용함으로써 부하변동에 빠르게 대응할 수 있으며, 주 전원의 느린 응답성을 보상하여 조종성능을 향상시킬 수 있다. 제안된 전력버퍼모듈은 시뮬레이션을 통해 그 유용성을 검증하였다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.1
• /
• pp.28-31
• /
• 2015

Electromotive forces (EMF) are generated by electrical equipment and engine shafting with a number of reasons. The shaft and bearing which is insulated by lubricating oil acts as a condenser, being able to store this EMFs. The electromotive force on the hull and shaft, with very few exceptions, has anode voltage on it. Electrical spark of the anode voltage on the shaft may lead to corrosion. Hence, in order to prevent ship's shaft and propeller corrosion, shaft grounding system are installed and operated. The shaft EMF voltage measurement methods was measured using 24bit 2 channels A/D converter of NI company and Labview software. 1 channel was propeller shaft's voltage and the other was M/E engine rpm gauge. In this paper, the generated electromotive force was analyzed and modeled with result of the analysis. As a result, the main shaft's electromotive force was in direct proportion to the main engine's revolution. However, over the specific R.P.M., it was reduced gradually. In addition, higher electromotive force on the shaft was identified during engine's ahead direction than the astern direction. The generated electromotive force is only minor compared to the shaft grounding system.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.39 no.1
• /
• pp.71-76
• /
• 2002

Because the driving time is increased under the low speed by rapidly increasing of vehicles, this paper is presented a new ignition control system for improvement the fuel economy, which only some of cylinders are using under the idle status or low speed and preserving the engine rpm. is applicable to effective in fuel economy. An actual hardware was made to prove this new control system. The developed variable cylinder engine concentrated the heat neat the cylinders in idle status or low speed, so there was a problem in re-ignition. It was the reason of a lot of exhaust gas, high fuel consumption and instability of engine revolution. In this paper, in order to solve above problem to show the improvement fuel economy using the new ignition control system and valve opening period at idle status of low speed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.6
• /
• pp.63-69
• /
• 2011

The Smart UAV must have the control characteristics of propulsion system necessary for both rotary aircraft and fixed wing aircraft though it equips turbo-shaft engine. To develop an electronic engine controller in the future, it is necessary to accumulate the experience of engine operation and data of tilt rotor aircraft. For this purpose, the computer programs which predict engine performance in the steady state and transient state can be utilized for the supplementation of flight test data. In this work, we developed a dynamic analysis program using engine performance data gathered during the flight tests. In addition the accuracy of the program was verified through comparison with flight test data and the results of steady-state performance analysis program.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1991.04a
• /
• pp.75-79
• /
• 1991

고도로 산업화가 진행됨에 따라 회전기계는 더욱 중요시되고 있으며 이의 성능 향상에 부단한 노력이 경주되고 있다. 특히 우주 시대의 개막과 더불어 우주선 및 인공위성에 사용하기 위해 초소형이며 초고속의 고성능회전모타 를 개발하기에 이르렀다. 한 예로서 미국립항공우주국(NASA)의 스페이스셔 틀에 사용되는 주엔진 터보펌프를 들 수 있는데 이 터보펌프는 접시만한 크 기로써 71000마력을 생성해 낸다. 이러한 가공할 만한 에너지 밀도와 유량을 감당해 내려면 종래의 회전기계보다는 훨씬 더 높은 회전속도를 가져야 한 다. 이러한 회전체는 큰 관성부하와 진 동 및 동안정성의 문제등을 내포하고 있다. 고성능 회전기계의 또다른 예로서 초정밀 가공용 공작기계를 들 수 있 다. 선반 혹은 밀링머신으로 초정밀가공을 행하기 위해서는 회전축의 진동이 극히 작아야 한다. 이와 같이 오늘날 갈수록 초고성능 초정밀도를 추구함에 있어서 회전축의 진동을 현장에서 모니터링하고 이 진동데이터를 분석하여 회전축을 제어하는 것이 강력히 요구되어진다. 따라서 in-situ 측정이 중요성 을 띠게 되었는데 이는 제어기술의 바탕이 되는 자료를 현장에서 제공할 수 있기 때문이다. 회전축 진동측정의 대상이 되는 것들은 모타, 발전기, 엔진 및 터빈등을 대표적으로 들 수가 있다. 여기서 소형회전기계의 축표면과 같 이 비교적 곡면을 이루고 있는 부분의 진동변위 측정에 신중한 고려가 요구 되어 진다. 이는 축의 곡면도에 따라 감도가 변화하기 때문이다. 따라서 평 판에 대한 calibration 챠트를 회전기계축진동 변위환상에 이용하면 곡률에 따라서 오차가 생기게 된다. 본 연구에서는 비접촉 축진동측정시 발생되는 오차에 대하여 검토하고자 한다. from the studies, the origin of ${\alpha}$$_1$peak was attributed to the detrapping process form trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of carriers from the shallow trap with 0.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.6
• /
• pp.104-110
• /
• 2018

Operating mode analysis of a liquid propellant rocket engine(LRE) is a crucial tool through the development of an engine. The operating mode analysis of an engine based on a collection of the acceptance tests of components shows discrepancies when compared to the test results. We propose a correction method for performance parameters to develop an engine analysis model for the gas generator cycle of an LRE. In order to simulate engine behavior, the performance parameters for the analysis model are tuned based on the test results of the 75tf engine of KSLV-II.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.25 no.5
• /
• pp.1-9
• /
• 2021

As part of the commercialization research of small gas turbine engines, starting and normal operation control logic research of small gas turbine engine was conducted. It was investigated how the igniter, starting motor and fuel pump/valve are controlled during the ignition and normal operation process and it was applied to the prototype engine control unit(ECU) of the small gas turbine engine for commercialization research. Based on the ground test results, an ECU for flight test is being developed, and after completion of the development, an altitude test will be performed through an altitude test facility of Korea Aerospace Research Institute.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.9
• /
• pp.3184-3189
• /
• 2010

To develop gasoline engine fuel pump, it is needed to measure the rotational speed of the pump. In general, because gasoline fuel pump is submerged in the fuel tank, it is difficult to measure the rotational speed directly. Currently, there are two popular methods measuring the rotational speed. One of them is using a piezoelectric accelerometer, and the other is using a current sensor. Originally, a piezoelectric accelerometer had been applied to measure the frequency of the motor vibration. A current sensor is measuring current frequency of the commutator slot. In this study, both the piezoelectric accelerometer and the current sensor have been applied on the fuel pump to calculate the rotational speed at the same time. As a result, the current sensor delivered highly accurate rotational speed information compared with that of the piezoelectric accelerometer. Especially, low rotational speed region, the current sensor shows very robust measuring characteristics. To measure the rotational speed within 1% error, the piezoelectric accelerometer needs to be set with less then 0.5Hz datum storage interval, and the current sensor needs to be set with less then 2.0Hz datum storage interval.