• 한국추진공학회지
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• 제19권3호
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• pp.89-95
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• 2015

7톤급 로켓엔진용 산화제펌프와 연료펌프에 대하여 물을 매질로 하는 성능시험을 수행하였다. 펌프는 전기모터로 구동되었고 설계 및 탈설계 유량비 조건에서 펌프의 수력성능과 흡입성능이 측정되었다. 양정-유량 곡선, 효율-유량 곡선, 양정-캐비테이션수 곡선을 얻었다. 개발된 펌프는 펌프 양정과 효율의 수력성능에 관한 설계요구조건을 만족시킬 수 있음을 확인하였다. 또한 흡입성능에 관한 설계요구조건을 만족시킨다.

• 한국유체기계학회 논문집
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• 제5권4호
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• pp.26-31
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• 2002

The heat produced by the fission in the fuel of HANARO, 30 MW of research reactor, was transferred from the primary cooling water to the secondary cooling water through heat exchangers. The secondary cooling water absorbing the heat was circulated by secondary cooling pumps and cooled through 33 MW of cooling tower. Each capacity of the three secondary cooling pumps was fifty percent ($50\%$) of full load. The two pumps were normally operated and the other pump was standby. One of the secondary cooling pumps has often made troubles by high vibration. To release these troubles the pump shaft has been re-aligned, the pump bearing has been replaced with new one, the shaft sleeve has been replaced with new one, the shaft and the impeller have been re-balanced representatively and/or the vibration of motor has been tested by disconnecting the shaft of pump. But the high vibration of pump cannot be cleared. We find out the weight balance trouble of the assembly in which the impeller is installed in the shaft. After clearing the trouble, the high vibration is relieved and the pump is operated smoothly. In this paper, the trouble solution shooting method of secondary cooling pump is described including the reason of high vibration

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.197-202
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• 2001

The heat produced by the fission in the fuel of HANARO, 30 MW of research reactor, was transferred from the primary cooling water to the secondary cooling water through heat exchangers. The secondary cooling water absorbed the heat was circulated by secondary cooling pumps and cooled through 33 MW of cooling tower. Each capacity of the three secondary cooling pumps was fifty percent ($50\%$) of full load. The two pumps were normally operated and the other pump was standby. One of the secondary cooling pumps has often get troubles by high vibration. To release these troubles the pump shaft has been re-aligned, the pump bearing has been replaced with new one, the shaft sleeve has been replaced with new one, the shaft and the impeller have been re-weight balanced representatively or the vibration of motor has been tested by disconnecting the shaft of pump. But the high vibration of pump cannot be cleared. We find out the weight balance trouble of the assembly that the impeller is installed in the shaft. After clearing the trouble, the high vibration is released and the pump is operated with smooth. In this paper the trouble solution of secondary cooling pump is described including the reason of high vibration.

• 대한기계학회논문집A
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• 제39권2호
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• pp.211-217
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• 2015

환경 문제 및 화석연료 고갈에 대한 관심으로 인하여 배기가스에 대한 규제는 나날이 엄격해지고 있으며 높은 연비에 대한 수요는 지속적으로 증가하고 있다. 이러한 시대적 요구를 뒷받침하기 위하여 저배기-고연비가 특징인 하이브리드 굴삭기가 현실적인 대안으로서 각광받고 있으며 지속적으로 연구되고 있다. 본 연구에서는 선회 구동 전동기, 엔진보조 전동기, 울트라 캐패시터, 전력변환장치를 중형 굴삭기에 탑재한 복합형 하이브리드 굴삭기를 개발하였으며, 일반적인 복합형 하이브리드 굴삭기의 연비개선요소(선회 구동 에너지 회생, 엔진 작동 속도 변경)외에 추가적으로 적용된 연비개선 방법론들에 대하여 다루고 있다. 본 방법론들을 적용함으로써 연비와 운전 조작성을 동시에 개선할 수 있었다.

• International Journal of Automotive Technology
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• 제8권6호
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• pp.791-798
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• 2007

The hydraulic hybrid vehicle(HHV) is an application of hydrostatic transmission technology to improve vehicle fuel economy and emissions. A relatively lower energy density of hydraulic accumulator and complicated coordinating operations between two power sources require a special energy management strategy to maximize the fuel saving potential. This paper presents a new type of configuration for parallel HHV to minimize the disadvantages of the hydraulic accumulator, as well as a methodology for developing an energy management strategy tailored specially for PHHV. Based on an analysis of the optimal energy distribution between two power sources over a representative urban driving cycle with a Dynamic Programming(DP) algorithm, a fuzzy-based optimal torque management strategy is designed and developed to control the torque distribution. Simulation results demonstrates that the optimal torque management strategy maximizes the advantages of this hybrid type of configuration, and the high power density characteristics of hydraulic technology effectively improve the robustness of the energy management strategy and fuel economy of the PHHV.

• 한국자동차공학회논문집
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• 제24권4호
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• pp.401-407
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• 2016

For high fuel economy, many kinds of unit in vehicle have been developed. In steering system, as a result, HPS(Hydraulic Power Steering) system has been replaced as EHPS and EPS system. But the structures of these systems are totally different, and that causes the uncertainty of fuel economy evaluation. Therefore we undertake to research to find results and tendency of fuel economy and energy in steering system. For accurate evaluation, we modeled different types of steering systems on same vehicle model. The simulation came into action on various driving cycle. The driving condition is designed to show standby power of pump. Results show differences of fuel efficiency and energy consumption.

• Tribology and Lubricants
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• 제28권4호
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• pp.167-172
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• 2012

The turbo pump of a liquid rocket engine is composed of three main parts: the oxidizer pump, fuel pump, and turbine. Liquid oxygen ($LO_X$) is the working fluid in the cryogenic environment in the oxidizer pump, but tests are usually performed using liquid nitrogen ($LN_2$), which has a boiling point similar to that of $LO_X$ but is comparatively safer and easier to use for the test. In this study, a bearing test rig is developed and its performance is evaluated using a cryogenic ball bearing with $LN_2$ as the working fluid. Verifying the performance of the bearing test rig is crucial for ensuring correct working of the turbo pump unit in the liquid rocket engine. A stable test rig for the bearing in a cryogenic environment makes the bearing technology enhance its reliability. The test results show that the system operates stably and the requirement of performance time of 500 s is met. The test results of temperature, motor speed, and torque are discussed. The developed cryogenic bearing test rig is expected to help in widening knowledge and expanding research on ball bearings in the future.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.268-270
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• 2009

This paper proposes a simple starting method to arrange the rotor position of the blushless DC motor (BLDC) without additional sensors and any information of motor parameters. Both the stator current and time period for arranging the rotor position can be easily adjusted by modulating a pulse width of switching devices. Using the proposed method, it is demonstrated experimentally that the BLDC starts up very smoothly.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.166-174
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• 2002

Power steering systems far automobile are becoming ever more popular because they reduce steering efforts of the drivers, especially during parking lot maneuver. In this paper, the controller of the motor driven hydraulic power steering(MDHPS) has been designed and developed. This system uses a power source of DC motor instead of engine power source for power steering drive oil pump. The developed MDHPS system is accomplished a highly sensitive power steering resulted from electronic control under variable driving condition. Furthermore, this system is more improvement than type of engine driving far fuel economy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1366-1370
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• 2005

As the development of microprocessor technology, electric power steering (EPS) system which uses an electric motor came to use a few years ago. It can solve the problems associated with hydraulic power steering. The motor only operates when steering assistance is needed, so it can save fuel and can reduce weight and cost by eliminating hydraulic pump and piping. As one of performance criteria of EPS systems, the transmissibility from road wheel load to steering wheel torque is considered in the paper. The transmissibility can be studied by fixing the steering wheel and calculating the torque needed to hold the steering wheel from road wheel load. A proportion-plus-derivative control is needed for EPS systems to generate desired static torque boost and avoid transmissibility of fluctuation. A pure proportion control can't satisfy both requirements.