• The Journal of the Acoustical Society of Korea
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• v.21 no.1E
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• pp.42-48
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• 2002

In this paper, a computer simulation method is presented far the dynamic analysis of a hydraulic engine mount system. The hydraulic engine mount system controls the damping characteristics using the viscosity of fluid flow. The complex stiffnesses of the main rubber for the hydraulic engine mount system are computed using a finite element analysis. The equations of motion considering the parameters of the hydraulic engine mount system are derived. To investigate the effects of the hydraulic engine mount system, the computer simulation running over a typical rough road is carried out using a vehicle dynamic model. These results are compared with those of the conventional rubber mount system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.3
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• pp.269-278
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• 2011

The details of engine manufacturer's engine simulations are generally kept secret and only those parameters that are used for control purposes are accessible to users. Hence, there is often only a limited amount of data accessible for creating a performance model of the engine. The performance modeling of a low bypass turbofan engine for supersonic aircraft is described herein. The Pratt and Whitney F100-PW-229 engine has been employed for low bypass turbofan engine performance modeling. Published data from the open literature are used as initial data for building the F100-PW-229 engine performance model. The unknown components' characteristics were estimated by optimization of parameters using by adaptive random search method and sensitivity analysis with respect to design variables. The engine performance model was evaluated to be properly constructed through the comparison of result of engine performance analysis and engine deck data.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.805-813
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• 2011

The dynamic stress of the diesel engine block is analyzed by using flexible-body dynamic analysis. Multiple loadings including the pressure load due to gas combustion, thermal load, and dynamic load are considered. Thermal load is assumed constant, however, pressure load and dynamic load are treated as time dependent. The present work is focused on the dynamic stress analysis, especially on finding critical points of the engine block. The analysis model includes four parts - engine block, generator, bed, and mounts. On the other hand, crank shaft, pistons, and main bearings are excluded from the model. However, their dynamic effects are applied by dynamic forces, obtained in the separate analysis. Dynamic stress is found by using flexible body dynamic analysis, and compared to the measured data.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.79-88
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• 2010

This paper dealt with the performance modeling of a low bypass turbofan engine for supersonic aircraft. The Pratt and Whitney F100-PW-229 engine has been employed for low bypass turbofan engine performance modeling. Generally, the complete commercially-classified informations concerning the engine are unknown. The components' generic characteristics and assumptions made in order to build the F100-PW-229 engine performance model using by the published data from the open literature as basic data are described. Through the comparison of engine performance model's analysis data using Gasturb11 with engine deck data showed that the engine performance model was evaluated to be properly constructed.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.61-66
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• 2015

Homogeneous charge compression ignition (HCCI) engine combines the combustion characteristics of a compression ignition engine and a spark ignition engine. HCCI engines take advantage of the high compression ratio and heat release rate and thus exhibit high efficiency found in compression ignition engines. In modern research, simulation has be come a powerful tool as it saves time and also economical when compared to experimental study. Engine simulation has been developed to predict the performance of a homogeneous charge compression ignition engine. The effects of compression ratio, cylinder pressure, rate of pressure rise, flame temperature, rate of heat release, and mass fraction burned were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion characteristics model for a homogeneous charge compression ignition engine running with isooctane as a fuel and effect of compression ratio.

• Journal of Mechanical Science and Technology
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• v.16 no.7
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• pp.975-985
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• 2002

This paper deals with theoretical model developed for analyzing the heat transfer of automotive cooling systems. The model has a modular structure which links various cooling system submodels. From the model, heat transfer rate of automotive cooling systems can be predicted, providing useful information at the early stages of the design and development. The aim of the study is to develop a simulation program for automotive cooling system analysis and a performance analysis program for analyzing heat exchanger. Heat release rate from combustion gas to coolant through the cylinder wall in engine cylinder was analysed by using an engine cycle simulation program. In this paper, details of each submodel are described together with the overall structure of the vehicle model.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.158-165
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• 1996

The knowledge of air flow in an engine room has become more and more important in recent car design. The fluid flow in the engine compartment was investigated by numerical analysis. Due to the complex geometry of the engine compartment, mesh generation is a time-consuming job. In this research, the "ICEM" code was used to generate meshes by the Cartesian mesh model. The Reynolds-averaged Navier Stokes equations, together with the porous flow model for radiator and condenser, were solved. Computation was performed for the steady, incompressible, and high speed viscous flow, adopting the standard K-ε turbulence model. The "STAR-CD" code was used as a solver. The effect of car front openning area on the flow in engine room was also investigated.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.10-17
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• 2001

The performance of a radiator is generally determined using a wind tunnel, in which the air velocity is uniform. However, when it is installed in a car, the distribution of the air velocity becomes nonuniform due to front-end openings, cross members, and horns etc., resulting in lower performance. In this study, several underhood flow simulations have been first performed to get flow rates and velocity distributions over the radiator. Secondly heat release rates are calculated by both a performance curve and a radiator model. Finally, using an engine cooling system simulator, radiator-top-tank temperature is predicted and the variations of heat release rate and radiator-top-tank temperature with nonuniformity of air velocity distributions are analyzed. The results show that the current engine cooling model successfully accounts for the nonuniformity effects that should be considered for higher accuracy in predicting engine cooling performance.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.131-137
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• 1996

The existing digital governors are in the beginning stage. Placing the focus on the marine site, most of the digital governors developed are still using the simple PID algorithm. But, the performance of a diesel engine is widely changed according to the parameters of the PID controller. So, this article describes a new method to adjust the parameters of the PID controller in a marine digital governor. In this paper, the diesel engine is considered as a nonoscillatory second order system. A new method to adjust the parameters of the PID controller for speed control of a diesel engine is proposed by means of the model matching method. Also, the simulations by numerical methods are carried out in cases of the exact understanding or out of the parameters of a diesel engine respectively. And this paper confirms that the proposed new method here is superior to Ziegler & Nichols's method through the comparisons and analysis of the characteristics of indicial responses.

• Journal of Power System Engineering
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• v.2 no.2
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• pp.20-26
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• 1998

Heat release data were obtained by analysis of cylinder diagrams from a test engine, naturally-aspirated small-size four-stroke DI diesel engine. These data were used to decide empirical coefficients of Whitehouse-Way's model, single zone combustion model. Finally, the comparison of calculated with experimental results was performed, and the accuracy of calculated versus experimental data of the model in predicting engine heat release and cylinder pressure was demonstrated.