• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3315-3325
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• 1994

To study the variation of charging efficiency in the engine intake, the method to change the natural frequency of intake system using the intake control valve was studied and it has been used in actual engine to increase the intake air. In this paper, the method of characteristics was used to analyze the non-steady state and compared with the experimental data of the 6-cylinder diesel engine showing the effectiveness of the method theoretically.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.62-74
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• 2001

In this study, the prediction of performances and emissions of the gasoline engine of a light passenger car has been accomplished. The method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyze the flow in the intake and exhaust systems. For in-cylinder calculation, the single-zone model was adopted for the periods of the intake, exhaust, compression and the expansion of the burnt gas and the 2-zone expansion model was applied to the period of combustion process. The simulation program was verified by comparison with the experimental values both for the naturally aspirated engine and the turbocharged engine showing good agreements. Using the simulation program, multi-valve system and turbocharging were examined as a means of increasing engine Performances.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.26-36
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• 2010

This paper provides a description of the combustion model to obtain an accurate dynamic engine phenomena that satisfies real-time simulation for model-based engine control. The combustion chamber is modeled as a storage device for mass and energy. The combustion process is modeled in terms of a two-zone model for the burned and unburned gas fractions. The mass fraction burnt is modeled in terms of a Wiebe function. The instantaneous net engine torque is calculated from the engine speed and the instantaneous piston work. The modeling accuracy has been tested with a cylinder pressure data on a test bench and also the ability of real-time simulation has been checked. The results show that combustion model yields sufficiently good performance for the model-based control logic design. However the influence factors effected on model accuracy are some room for improvement.

• Journal of KSNVE
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• v.9 no.1
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• pp.42-48
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• 1999

In this paper, a computer simulation method for dynamic analysis of the hydraulic engine mount system is proposed. The hydraulic engine mount system controls the damping characteristics using the viscosity of fluid flow The complex stiffness of the main rubber of the hydraulic engine mount system is computed by finite element analysis for the viscoelastic materials and hydro-static elements. A numerical analysis method is presented to solve nonlinear equations of the hydraulic engine mount system. which is composed of an engine mass, fluid in inertia track and a vertical inertia force of reciprocating mass in the engine. Also. dynamic properties of the hydraulic engine mount system are analyzed in the frequency domain. Effects of the hydraulic engine mount system running over the rough road are investigated using a vehicle dynamic model. These results are compared with those of the rubber mount system.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.101-107
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• 2005

In this paper, optimized operating parameters were found using multi-dimensional engine simulation software (KIVA-3V) and micro-genetic algorithm for heavy duty diesel engine. The engine operating condition considered was at 1,737 rev/min and 57 % load. Engine simulation model was validated using an engine equipped with a high pressure electronic unit injector (HEUI) system. Three important parameters were used for the optimization - boost pressure, EGR rate and start of injection timing. Numerical optimization identified HCCI-like combustion characteristics showing significant improvements for the soot and $NO_X$ emissions. The optimized soot and $NO_X$ emissions were reduced to 0.005 g/kW-hr and 1.33 g/kW-hr, respectively. Moreover, the optimum results met EPA 2007 mandates at the operating point considered.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.751-767
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• 1994

Recent developments of S.I. engine, aiming to higher power, better fuel economy, lower air pollution and better driveability, have much focused on the importance of the role of computer simulation in engine research and development. In this point of view, improving engine performance requires finding some means to improve volumetric efficiency. Up to now there have been several attempts to optimize the intake and exhaust system of internal system of S.I. engine by computer simulation. There appear to be few studies available, however, of such simulation & experimental studies applied to the optimization of exhaust manifold configuration. In this study, gas exchange & power process of 4 cylinder S.I. Engine was studies numerically & experimentally, and governing equation of a one-dimensional unsteady compressible flow and combustion process were respectively solved by a characteristics method and 2-zone model. The aim of this study is to predict and investigate the influence of pressure wave interaction at the exhaust systems on engine performance with widely differing exhaust manifold configuration.

• Journal of ILASS-Korea
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• v.26 no.2
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• pp.81-87
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• 2021

This study was performed to calculate the swirl ratio of a diesel engine intake port by a 1D computer simulation under actual engine operating conditions. The swirl ratio of the intake port was simulated according to the change of the engine speed during the operation of the motoring without fuel injection. The swirl ratio of the intake port was simulated according to changes in the crank angle during the four-cycle operation of intake, compression, expansion and exhaust. The swirl ratio represented by the three regions of the piston, center and squish was simulated. Among the three regions, the piston-region swirl ratio is important for effective air-fuel mixing in the engine cylinder. In particular, it was confirmed during the simulation that the piston swirl ratio before and after the compression top dead center (TDC) point when fuel is injected in the DI diesel engine can have a significant effect on the mixing of air and fuel. It was desirable to set the average piston swirl ratio over a crank angle section before and after compression TDC as the representative swirl ratio of the cylinder head intake port according to the change of the engine speed.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.30-38
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• 2003

The measurement on the working gas flow in the closed cycle diesel engine is insufficient to Identify its operating condition because of lack of sensors available. For this reason, the determination of optimum operating condition and controller parameters requires heavy experimental efforts. A simulation program is developed to minimize the experimental efforts. For the development of the simulation program, mathematical models are derived based on the physical laws and linear regression. The validity of the simulation program is demonstrated using the measured data of the closed cycle diesel engine.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.51-62
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• 2010

Modeling and Simulation techniques are useful to construct executable battlefields and forces on computers, and have been utilized to analyze effectiveness of weapon systems in the computerized war environment. However, most weapon simulations so far have exhibited low reusability and extensibility, since they have been developed for specific simulation objectives with different structures and simulation engines. In this paper, we identify requirements for defense modeling and simulation activities and propose a simulation engine to support the identified requirements. We define the software architecture of the proposed engine, in a way to efficiently provide usability, component-based reusability, interoperability, and reuse-based development.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.51-58
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• 2002

A simulation model has been developed to predict the performance of 5-valve gasoline engine by gas exchange process with combustion model. In this study, we simulated the intake flow characteristics and performance of 5-valve engine with entwine speed and we compared the 5-valve engine performance with that of 4-valve engine. As a result. the calculated value was in consistency with the measured value relatively. The performance of 5-valve engine was higher than that of 4-valve engine in high engine speed region.