• Title/Summary/Keyword: Inertia effect

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Engine-CVT Integrated Control Algorithm Considering Power train Loss and CVT Response Lag (동력전달계 동력손실계 CVT 응답지연을 고려한 엔진-CVT 통합제어 알고리즘)

  • 김달철;김현수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.1
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    • pp.112-121
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    • 2001
  • In this paper, an engine-CVT integrated control algorithm is suggested by considering the powertrain loss, inertia torque and the CVT ratio response lag. The integrated control algorithm consists of (1) the optimal engine power calculation and (2) determining of the optimal throttle valve opening and the optimal CVT ratio. The optimal engine power is obtained by compensating the inertia torque due to the CVT ratio change and the powertrain loss that is calculated iteration procedure. In addition, an algorithm to compensate the effect of the CVT ratio response lag on the drive torque is suggested by the engine speed compensation causing the increased optimal CVT ratio. Simulation results show that the engine-CVT integrated control algorithm developed in this study makes it possible to obtain better engine operation on the optimal operating line, which results in the improved fuel economy while satisfying the driver's demand.

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An Experimental Study of Engine Mount Optimization to Improve Noise and Vibration Quality of F.R. Vehicle (후륜구동 차량의 소음 진동 성능향상을 위한 엔진마운트 최적설계에 관한 실험적 연구)

  • 이준용;김찬묵
    • Journal of KSNVE
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    • v.7 no.4
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    • pp.681-688
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    • 1997
  • The purpose of engine mount system is to reduce the noise and vibration caused by engine vibration, and to decouple the roll and bounce mode at idle. To reduce the noise and vibration level in a vehicle, it is important to make the design optimization of engine mount system that consider the moment of inertia and inclination of mount rubber. As a result, according to the definition of Torque Roll Axis (TRA), the vibration axis at idle must be on the TRA or very close to it. In this paper, we studied the effect of the design optimization of engine mount system. And we have achieved good improvements in noise and vibration quality of F.R. vehicle.

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Steady and Unsteady Rotating Flows between Concentric Cylinders (동심원 환내의 정상.비정상 회전 유동)

  • 심우건
    • Journal of KSNVE
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    • v.7 no.4
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    • pp.613-620
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    • 1997
  • Steady and unsteady flows between rotating cylinders are of interest on lubrication, convective heat transfer and flow-induced vibration in large rotating machinery. Steady rotating flow is generated by rotating cylinder with constant velocity while the unsteady rotating flow by oscillating cylinder with homogeneoysly oscillating velocity. An analytical method is developed based on the simple radial coordinate transformation for the steady and unsteady rotating flows in concentric annulus. The governing equations are simplified from Navier-Stokes equatins. Considering the skin friction based on the radial variation of circumferential flow velocity, the torques acting on the fixed and the rotating cylinder are evaluated in terms of added-inertia and added-damping torque coefficients. The coefficients are found to be influenced by the oscillatory Reynolds number and the radius ratio of two cylinders; however, the effect of the oscillatory Reynolds number on the coefficients is minor in case of relatively low radius ratio.

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Contouring Error of a Machine Tool at Inflection Points (변곡점에서 공작기계의 윤곽오차)

  • 안일혁;김성수;민경석;최우천;홍대희
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.11
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    • pp.166-170
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    • 2003
  • Contouring errors are important especially for high speed and precision machining. In this study, contouring errors along contours having inflection points are studied. When a table of a machine tool moves along a circular path, acceleration acts toward the center of the circle. Thus, at inflection points, acceleration as well as inertia force changes its direction abruptly. The effect of inertia force on the contouring error is investigated in this study. It is found that the contouring error at an inflection point is proportional to the acceleration. This result can be useful in determining contouring errors along general paths.

A Study on the Discharge Pressure Ripple Characteristics of Variable Displacement Vane Pump (가변용량형 유압 베인펌프의 토출압력맥동 특성 연구)

  • 장주섭;김경훈
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.106-114
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    • 2003
  • The pressure ripple in the delivery port is caused by flow ripple, which is induced by variation of pumping chamber volume. The other reason is the reverse flow from the outlet volume produced by pressure difference between pumping chamber and outlet volume, when the pumping chamber is connected with the outlet volume. In this study, a mathematical model is presented for analyzing discharge pressure ripple, which includes vane detachment, cam ring movement , and fluid inertia effects in V-groove in the side plate. From the analysis and experiment, it was found that V-groove on the side plate, coefficient of spring supporting the cam ring, and average discharge pressure are the main factors of discharge pressure ripple in variable displacement vane pump. The theoretical results, provided in this study, were well agreed with experimental results. The analytical model to estimate the magnitude of pressure ripple in this study is expected to be used f3r the optimal design of the variable displacement vane pump.

The dynamic response of a prototype steel floor using velocity-source type of excitation

  • Magalhaes, Max D.C.
    • Structural Engineering and Mechanics
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    • v.46 no.3
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    • pp.371-385
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    • 2013
  • Vibration isolators and anti-vibration mounts are ideal, for example, in creating floating floors for gymnasiums, or performance spaces. However, it is well-known that there are great difficulties on isolating vibration transmission in structural steel components, especially steel floors. Besides, the selection of inertia blocks, which are usually used by engineers as an effective vibration control measure, is usually based on crude methods or the experience of the engineers. Thus, no simple method or indices have been available for assessing the effect of inertia blocks on vibration isolation or stability of vibratory systems. Thus, the aims of this research are to provide further background description using a FE model and present and implement a modal approach, that was validated experimentally, the latter assisting in providing improved understanding of the vibration transmission phenomenon in steel buildings excited by a velocity-source type of excitation. A better visualization of the mean-square velocity distribution in the frequency domain is presented using the concept of modal expansion. Finally, the variation of the mean-square velocity with frequency, whilst varying mass and/or stiffness of the coupled system, is presented.

Control of a Balance-Beam with Unknown Loads Using the Restoration Angle of a Gimbal

  • Yi Keon-Young;Kim Yong-Jun;Chung Sam-Yong;Han Song-Soo;Lee Sang-Heon
    • International Journal of Control, Automation, and Systems
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    • v.4 no.4
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    • pp.524-528
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    • 2006
  • A controller built with the gyro effect for a balance-beam can freely control the attitude of an unstructured object by changing the position of an inner gimbal. In this paper, we propose a new balance-beam controller that can detect the inertia of the load to limit the velocity of the load commanded by a user. We found that when there was smaller load inertia, a larger restoration displacement occurred. Therefore, the load can be identified by issuing a predefined command to measure the restoration displacement, which enables us to construct a controller that can limit the angular velocity of the load by planning the motion. Experimental results show the performance of the controller with different loads.

Free Vibration Analysis of Circular Arches with Rectangular Hollow Section (구형 중공단면을 갖는 원호아치의 자유진동 해석)

  • Lee, Tae-Eun;Lee, Byoung-Koo;Park, Kwang-Kyou;Yoon, Hee-Min
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.50-53
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    • 2008
  • The differential equations governing free vibrations of the elastic arches with rectangular hollow section are derived in polar coordinates, in which the effect of rotatory inertia is included. Natural frequencies is computed numerically for circular arches with both clamped ends and both hinged ends. The lowest four natural frequency parameters are reported, with the rotatory inertia, as functions of three non-dimensional system parameters: the breadth ratio, the thickness ratio and the shape ratio.

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A REAL TIME CFD SIMULATION OF THE VERTICAL-AXIAL WIND TURBINE (전산해석을 이용한 수직축 풍력터빈의 실시간 공력해석)

  • Lee, M.S.;Han, B.Y.;Park, H.K.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.147-154
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    • 2010
  • The world is gradually running short of fossil fuel. Currently, the role of wind turbine is attracting great attention from all over the world. The objective of this study is to investigate blades of Vertical-axial wind turbine (VAWT) for optimum design using the CFD from the aerodynamics point of view. Because one of the performance of wind turbine depends on shape of blades, the study of comparing one gyro mill type blade and a modified one was carried out. Using the results of computation, we calculated and compared RPM for both models at same wind velocity. And we calculated angular acceleration and moment of inertia to find torque in every time-step. And the pressure contour and velocity profile around the blade were analyzed Also, this study is performed to calculate the wake effect.

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Free Vibrations of Arches in Rectangular Coordinates (직교좌표계에 의한 아치의 자유진동 해석)

  • Lee, Tae-Eun;Ahn, Bae-Soon;Kim, Young-Il;Lee, Byoung-Koo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.394.2-394
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    • 2002
  • The differential equations governing free vibrations of the elastic arches with unsymmetric axis are derived in the rectangular coordinates rather than in polar coordinates, in which the effect of rotatory inertia is included. Frequencies and mode shapes are computed numerically for parabolic arches with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. (omitted)

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