• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.3
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• pp.243-250
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• 2009

The clutch with torsional damper is installed on a passenger car with manual transmission, which not only transmits the power generated by engine to the transmission but also absorbs the shock and vibration from the engine. The torsional damper in the clutch dissipates the torsional vibration energy and eliminates the resonance in the driveline but high damping in the damper causes the increase of the vibration level which is against the comfort and durability. In this study, a dynamic model for the passenger car driveline with manual transmission was developed to investigate the vibration and the effects of characteristics of the driveline. With the dynamic model, the vibration characteristics of driveline were examined by the mode analysis and driving simulation, and the effects of hysteresis torque and spring constant were investigated. The vehicle tests with prototype torsional dampers were preformed and the test results showed good agreements with the simulation.

• International Journal of Automotive Technology
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• v.3 no.2
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• pp.63-70
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• 2002

Future on-board vehicle control systems can be further improved through new types of mechatronic systems. In particular, these systems' capacities for interaction enhance safety, comfort and economic viability. The Automotive Engineering Department (fzd) of darmstadt University of Technology is engaged in research of the mechatronic vehicle corner, which consists of three subsystems: sensor tire, electrically actuated wheel brake and smart suspension. By intercommunication of these three systems, the brake controller receives direct, fast and permanent information about dynamic events in the tire contact area provided by the tire sensor as valuable control input. This allows to control operation conditions of each wheel brake. The information provided by the tire sensor for example help to distinguish between staightline driving and cornering as well as to determine $\mu$-split conditions. In conjunction with current information of dynamic wheel loads, tire pressures and friction tyre/road, the ideal brake force distribution can be achieved. Alike through integration of adaptive suspension bushings, elastokinematic behaviour and wheel positions can be adapted to manoeuver-oriented requirements.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.7
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• pp.614-621
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• 2001

The controllers for a full car 7-DOF model with 4 active or semi-active suspension units are designed and evaluated in this research. The control algorithms for suspension systems, such as full state feedback active, full state feedback semi-active, sky-hook active, sky-hook semi-actvie, and on-off suspension systems, are analyzed and evaluated with respect to ride comfort. The vehicle dynamic performances are expressed by response curves to a bump input, performance indices for asphalt road input, and frequency characteristic curves. Heaving, rolling, and pitching inputs are applied to the vehicle dynamic system to evaluate frequency characteristics. The simulation results show that the ride quality of the sky-hook controller approaches that the full state feedback controller more closely in semi-active suspension system than in active suspension system. For the implementation of a vehicle with sky-hook suspension control systems in this paper, 7 velocity sensors are required to measure the states.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.251-256
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• 2012

Hanging sleepers are frequently observed in the ballasted track with the rail of high rigidity. These hanging sleepers at the high speed line could cause such large dynamic force compared to those at the conventional line. This dynamic force would, in turn, deteriorate train running stability as well as riding comfort, and accelerate irregularity of track and failure of track materials, leading to a sharp increase in track maintenance cost. When the wheel-rail contact spring exhibits nonlinear behavior and some components of the system like hanging sleeper exhibit bi-linear behaviors, an effective analytical method is proposed for train-track interactions. The verification of the present method is carried out comparing numerical results by the present method and those by Ono's method of RTRI.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3446-3451
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• 2007

The thermal behavior of a building in response to heat input from an active solar space heating system is analysed to determine the effect of the variable storage tank temperature on the cycling rate, on and off temperature of a heating cycle and on the comfort characteristics of room air temperature. A computer simulation of the system behavior has been performed and verified by comparisons with various parameters. Especially, this study is focused on the effect of the system's performance when subjected to dynamic cooling loads. The heat input to the absorption system is provided by an array of solar collectors that coupled to a thermal storage tank.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2838-2843
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• 2011

Recently, the floating slab track that can effectively mitigate the vibration and structure-borne noise is being discussed to be adopted. The floating slab track which is a track system isolated from the sub-structure by vibration isolators. Unsimilarly to conventional track and the slab deflection is large. Therefore, the running safety and ride comfort should be investigated. Especially at slab joint since the load cannot be transferred, the possibility that the dynamic behavior of track and train became unstable is high. Thus, in general dowel bar are often installed at slab joints. To determine the appropriate dowel ratio the load transfer characteristics should be investigated. In this study, dowel bar joint is modeled by equivalent shear spring and this model is verified by comparison with experimental results. Using the proven model, the load transfer efficiency and deflection at slab joint according to dowel ratio, and stiffness and spacing of vibration isolator were examined.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1856-1861
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• 2011

As a secondary suspension, the air spring has not good lateral stiffness characteristics. In order to make up for this weak point, lateral damper is used between bogie and carbody. The lateral vibration of carbody can be reduced by the lateral damper. When the damping force of lateral damper becomes worse, the running stability and ride comfort of the railway vehicle go down. Simultaneously the lateral motion of carbody is increased. In this study, the lateral displacement of carbody was studied by the multibody dynamic analysis in accordance with lateral damping force to find the cause of abnormal noise(impact noise) when the vehicle is running. The suitable lateral damping force was reviewed in order not to generate abnormal noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.10
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• pp.902-908
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• 2013

The input torque ripple induced by combustion engines is a significant source of NVH(noise, vibration and harshness) problem in automotive transmissions. Because this torque fluctuation is primarily transmitted to the input shaft of automotive powertrains(e.g., automatic transmissions) when the lock-up clutches are closed, a torsional damper with helical springs is generally inserted between engine and transmissions to isolate the input vibratory energy, which is essential for the passenger comfort. The torsional vibration isolator exhibits frequency ranges in which there is low vibration transmissibility. However, the isolation performance is currently evaluated through the static torsional spring characteristics. In this study, the transmissibility of torsional spring dampers, essential dynamic performance index for vibration isolator, is first experimentally evaluated.

• International Journal of Automotive Technology
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• v.1 no.1
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• pp.56-60
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• 2000

The customers demand of a good vehicle agility consists of a quick reaction of the vehicle with the actuation of the throttle pedal on one hand and a high comfort level of vibration and noise within the vehicle on the other hand, which means the reduction of disturbing side effects. In order to achieve a satisfactory compromise it is necessary to gain a deeper understanding of the complex, high dynamic vibrations system "vehicle / drive train". For several years the ika has been carrying out such detailed vehicle investigations and test bench measurements in addition to comprehensive CAE analysis for various research projects in partnership with different vehicle manufacturers.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.122-127
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• 2005

The styling of automobile wheels and their effect on vehicle appearance has increased in importance in recent years. The wheel designer has been given the task of insuring that a wheel design meets its engineering objectives without affecting the styling theme. The wheel and tire system is considered as a vehicle component whose dynamic modal information of the tire/wheel system are employed in the modal synthesis model of the vehicle. The vibration characteristics of a automobile wheel play an important role to judge a ride comfort and quality for a automobile. In this paper, the vibration characteristics of a Al-alloy and steel wheel for automobile are studied. Natural frequency, damping and mode shape are determined experimentally by frequency response function method. Results show that wheel material property, size and design are parameter for shift of natural frequency and damping.