• Journal of Power System Engineering
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• v.12 no.2
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• pp.23-28
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• 2008

The primary objective of this study is to truly understand reaction force be due to engine exciting force. Exciting forces of the engine apply a source of the vehicle NVH(Noise, Vibration, Harshness). To understand reaction force was applied MSC.Nastran software. Analyzed frequency response analysis of powertrain mount system. First, engine exciting force was applied field function. Also nonlinear characteristics was applied field function : such as dynamic spring constant and loss factor. And nonlinear characteristics was applied CBUSH. Generally characteristics of rubber mount is constant frequency. But characteristics of hydraulic mount depend to frequency. Therefore nonlinear characteristics was applied. Powertrain mounting system be influenced by powertrain specification, mount position, mount angle and mount characteristics etc. In this study, we was analyzed effects of powertrain mounting system. And we was varied dynamics spring constant and loss factor of mounts.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.399-404
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• 2002

Analyzing acoustic-structural systems such as automobiles and aircraft the FRF-based substructuring method is one of the most powerful tools. In this paper, an optimization procedure far the engine mount system of passenger car has been presented using the design sensitivity analysis based on the multi-domain FRF-based substructuring formulation. The proposed method is applied to an optimization problem of the engine mount system, of which objective is to minimize the interior sound over the concerned rpm range. The design variables selected are the stiffnesses of the engine mounts and bushes. Plugging the gradient information calculated by the proposed method into nonlinear optimization software, we can obtain the optimal stiffnesses of the engine mounts and bushings through design iterations. The optimized interior noise in the passenger car shows that the proposed method is very useful in the realistic situation.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.1
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• pp.58-62
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• 1999

This paper shows that is possible to identify the system's input-output dynamics exactly in the presence of unknown periodic disturbances for the Active Engine Mount Control Application .The disturbance frequencies and waveforms can be completely unknown and arbitrary. Only measurements of a control excitation signal and the disturbance-contaminated response are used for identification. Examples are given to illustrate the method, including the identification and vibration control of active engine mount for automobile.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.274-279
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• 2000

Driving of the engine makes unbalance forces which induces vibration to the engine mount system. Active vibration control must be performed to reduce the vibration and the propagation of structure-born sound. In this study, the engine system is modeled as 3-dim. vibration system including flexible structures and an effective active noise control method is proposed. Also, appropriate actuator and sensor locations and types are selected. The miniature of the engine vibration system with multi-input multi-output is built and an active vibration control with multiple filtered-X LMS algorithm is applied to it. The applied control method was effective to reduce the transmitted vibration power through the rubber mount It showed the feasibility of the control of the engine vibration systems with flexible structures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1907-1911
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• 2000

In this paper, classical vibration theories are summarized to design engine mount system of passenger vehicles. The vibrational characteristics of powertrain system and its equation of motion are introduced. Based upon the equation, the concept of the center of gravity, the principle inertia axis, the elastic center, and the elastic axis are defined and some new concepts are suggested. The theory of mode decoupling and the relationship between TRA (Torque Roll Axis) and roll mode are also reexamined to support the design concept of engine mount systems.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.731-744
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• 2007

A method for dynamic analysis and design calculation of a Powertrain Mounting System(PMS) including Hydraulic Engine Mounts(HEM) is developed with the aim of controlling powertrain motion and reducing low-frequency vibration in pitch and bounce modes. Here the pitch mode of the powertrain is defined as the mode rotating around the crankshaft of an engine for a transversely mounted powertrain. The powertrain is modeled as a rigid body connected to rigid ground by rubber mounts and/or HEMs. A mount is simplified as a three-dimensional spring with damping elements in its Local Coordinate System(LCS). The relation between force and displacement of each mount in its LCS is usually nonlinear and is simplified as piecewise linear in five ranges in this paper. An equation for estimating displacements of the powertrain center of gravity(C.G.) under static or quasi-static load is developed using Newton's second law, and an iterative algorithm is presented to calculate the displacements. Also an equation for analyzing the dynamic response of the powertrain under ground and engine shake excitations is derived using Newton's second law. Formulae for calculating reaction forces and displacements at each mount are presented. A generic PMS with four rubber mounts or two rubber mounts and two HEMs are used to validate the dynamic analysis and design calculation methods. Calculated displacements of the powertrain C.G. under static or quasi-static loads show that a powertrain motion can meet the displacement limits by properly selecting the stiffness and coordinates of the tuning points of each mount in its LCS using the calculation methods developed in this paper. Simulation results of the dynamic responses of a powertrain C.G. and the reaction forces at mounts demonstrate that resonance peaks can be reduced effectively with HEMs designed on the basis of the proposed methods.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.237-244
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• 2002

Analyzing acoustic-structural systems such as automobiles and aircraft, the FRF-based substructuring (FBS) method is one of the most powerful tools. In this paper, a general procedure for the parametric sensitivity analysis of vibro-acoustic problems has been presented using the multi-domain FRF-based substructuring formulation. For an acoustic-structural system sub-structured by multiple domains, the substructuring formulation gives the reaction farces on the interface boundaries. The design sensitivity formula is obtained from the direct differentiation of the reaction force expression with respect to the design vector. As a practical application, the proposed design sensitivity formula is applied to an engine mount system of passenger car. An objective of the problem is to identify the most effective engine mounts and bushes in minimizing the interior noise over the concerned rpm range. The comparison of the sensitivity results with those of the finite difference method shows excellent agreement. In addition, stiffness modifications of the mounts and bushes identified through the design sensitivity analysis lead to a successful decrease of the interior noise. This results show usefulness of the present method very well.

• ICROS
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• v.2 no.6
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• pp.14-19
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• 1996

본 해석에서는 새로운 기법을 사용하여 차량의 엔진에 의한 가진력이 차체에 최소한으로 전달되도록 엔진마운트의 최적 위치와 마운트의 강성을 결정하였다. 차량은 엔진과 차체 및 Suspension이 고려되어 16 자유도계로 모델링하였으며 각각의 입력 자료에 의하여 계산된 응답에 의하여 구한 마운트의 위치와 마운트의 강성을 통하여 엔진으로부터 차체로 전달되는 전달력을 최소화하는 마운트의 위치 및 강성의 최적화를 수행하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.585-588
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• 2013

Electric motor with reduction gear systems are being adopted recently as main propulsion on the special-purposed ships. These specialized ships or offshore vessels require higher power rating generators for propulsion and accommodation power supply. This study investigated the cause of exciter components failure in the view of excessive vibration, force or abnormal ship motion in service. Countermeasures are proposed to address the exciter component failure. A 1.4 MW class dual-fuel engine generator using rigid foundation for a LNG carrier was used as research model.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.304-309
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• 1998

In recent truck industry, ride quality improvement as well as payload capacity is a very important subject. In order to achieve this goal, it is necessary to study several sub-systems (powertrain, suspension, engine mount, exhaust, etc) of truck which are major components of vehicle. In this research, torsional vibration reduction method of 4$\times$2 truck powertrain is demonstrated by using computer simulation and experiment. First, truck powertrain is modeled as a vibration system and validity of developed model is verified by comparing free vibration results with experiment results. Second, Most key parameters which influence torsional resonance are examined utilizing mode analysis. Finally, frequency responses of truck powertrain are obtained and reduction counterplans of torsional vibration are suggested.