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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Automotive Engineers
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Journal DOI :
The Korean Society of Automotive Engineers
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Volume & Issues
Volume 2, Issue 4 - Jul 1994
Volume 2, Issue 3 - May 1994
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The Effect of The Initial Phase Angles of The Large-Scale Coherent Structures in a Spatially Developing Viscous Shear Layer
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 1~8
The Effect of Oil Rheology on Film Thickness in Engine Journal Bearing
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 9~17
Effect of Newtonian and non-Newtonian oils on minimum ol film thickness in engine journal bearing were investigated at various oil viscosities. The influence of oil viscosity and engine operating conditions on minimum oil film thickness of main bearing and con-rod bearing was examined. Minimum oil film thickness for Newtonian oils increased uniformly with kinematic viscosity. But the correlation between kinematic viscosity and minimum oil film thickness was very poor for non-Newtonian oils. According to the straight-line regression analysis for non-Newtonian oils, high temperature high shear viscosity at 1
increase the coefficient of determination from 0.41 to 0.77. Con-rod bearing showed better correlation between minimum oil film thickness and engine operating conditions than main bearing.
Local Buckling Characteristics of a column with I section
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 18~26
The buckling characteristics of I - shaped columns which are composed of thin web and equal upper/lower flange plates are generally classified into the local and global modes. In this paper, its local buckling problem has been formulated on the basis of the assumed buckling modes using the finite element method for beams and plates. The effects of local bucklings are studied for various size rations and end conditions of I-shaped columns. The calculated results are comparatively well consistent with values obtained from the existing studies. The global buckling characteristics calculated by the present method are in good agreement with the classical rigid web solution
Deduction of a Simplified Model for the Hydraulic Actuator for a Low-band Type Suspension System
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 27~38
In this paper, a simplified model of a hydraulic actuator system for a low-band type active suspension system is derived. To reduce the order of model, time constants of each chamber in hydraulic system are neglected except that of an accumulator. And the dynamics of a spool in the pressure control valve is regarded as a first-order system. The step response and the frequency response of the simplified second-order simulation model exhibit a good agreement with those of the actual system as well as those of the tenth-order simulation model. It is possible to simplify the tenth-order model to the second-order one. The low-band type active suspension model is built up by combining of a quarter car model test rig to testify the validity of the simplified model. The experimental results of suspension characteristics show that the simplified second-order hydraulic actuator model is reasonable to describe the dynamics of the actual hydraulic actuator system for a low-band type active suspension system.
Wall Impingement Behavior and Droplet Size Measurement in Diesel Spray
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 39~49
An experimental investigation was undertaken in a diesel spray to evaluate wall impingement behavior and droplet size distribution. Emphasis is placed on the possibility of the application for new combustion type which is based on OSKA-D type. Visualization were employed using optical scheme which was a spark shadowgraphy to observe the behavior of wall impingement caused by diesel spray vertically injected at the center of the combustion chamber. Droplet size measurements using Malvern system were made to quantify the visual observations with surface diameter of impingement. The effects of the surface dia. variation on the droplet size during injection with the wall impingement spray are discussed. It was found that for the wall impingement spray the droplet size becomes greatly small rather than the spray without the wall impingement and the droplet deposition rate of the injection fuel is decreased as the surface area of impingement becomes small.
Analysis of stamping for the Lower control arm using Explicit code
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 50~58
To examine the residual stress field resulting from stamping process for the lower control arm of a car, the explicit finite element analysis is performed for the stamping process by way of the ABAQUS Explicit. The residual stress is obtained in terms of the Von Mises stress and other parameters such as equivalent plastic strain, the change of blank thickness, the final configuration of the blank and the spring back effect are also considered. Moreover, discussed is the convergence of the explicit FEM versus the punch sped and the element discretization
A Multi-Polynomial Synthesis Method for DRRD Cam Profile Optimizations and Effects of Shape Factors on the Cam Lobe Area
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 59~71
A multi-polynomial method is proposed to synthesize DRRD cam profiles. A cam lift duration s divided into 10 sections, each of them is expressed by a polynomial equation. 12 design variables are extracted from the cam profile displacement, velocity, and acceleration curves. Because all the design variables have physical meanings which are familiar to most cam designers, it is easy to imagine a profile shape from the design variables. The design envelope of the method is wide enough to be used in DRRD automotive cam designs. Polydyne cams, widely used in automotive engines, are included into the envelope. Unlike Polydyne cams, the method provides capability of wide velocity factor variations, which gives much flexibility in flat-faced tappet design. Area factor of profiles designed by the method can be increased 5-10% compared to those of Polydyne cams without increasing acceleration factor. The method is especially useful for cam profile optimizations.
Effect of Non-Uniform Mixture on the 4 Cylinder S.I.Engine Performance
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 72~79
In an automotive spark ignition, it is important to form the proper mixture(air/fuel) on each driving condition for developing the stabilizing combustion and exhaust characteristics. Since most of supply fuel is attached on the inside wall of the intake manifold for unadequate atomization by fuel injection system, it brings a bad effect on combustion and exhaust caused by nonuniformity of fuel distribution to each cylinder and mixture variation. Also it affects engine performance variation and causes noises and vibration. In this study, we verified the effect of the mixture variation which is caused by fuel liquid film in an intake manifold on combustion characteristics and engine performance.
A Gemetric Kinematic Analysis of Constrained Multibody System
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 80~90
Basic constraint equations derived from orthogonality conditions between a pair of body-fixed vectors and a body-fixed vector or a vector between two bodies are reformulated by using relative coordinate kinematics between two adjacent reference frames. Arithmetic numbers of operations required to compute derivatives of the constraint equations are drastically reduced. A mixed formulation of relative and cartesian coordinates is developed to further simplify derivatives of the constraints. Advantages and disadvantages of the new formulation are discussed. Possible singularity problem of para llelism constraints is resolved by introducing an extra generalized coordinate. Kinematic analysis of a McPherson strut suspension system are carried out to illustrate use and efficiency of the new formulation.
and OH Density Measurement Using Tunable KrF Excimer Laser Light a Combustion Bomb via Planar Laser Induced Predissociative Fluorescence and Laser Rayleigh Scattering
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 91~99
Tunable KrF Excimer Laser is used here for measuring OH and
density distribustion in an open
/air premixed flame and in a combustion bomb. Laser Rayleigh Scattering(LRS) and Planar Laser Induced Predissociative Fluorescence(PLIPF) methods are used to obtain two-dimensional images of total and specific densities. Laser Excitation wavelengths are calibrated via flame images and combustion bomb images show good qualitative a greement with theoretical calculation. Furthermore images in a combustion bomb can be developed to study real Spark-Ignition engine combustions. Our experimental images show that there are no more collisional quenching problem at high pressure environment(including atmospheric pressure) using predissociative fluorescence technique. Further development to obtain two-dimensional temperature dustribution is ready to use eventhough it is not reported in this paper.
Observations on the Near-Nozzle Behavior of an Unsteady Fuel Spray
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 100~111
Observations on the near-nozzle behavior of an unsteady fuel spray through single cylindrical hole nozzle were made by phase Doopler anemometer and microphotographs. At the edge of the spray, droplet velocity peaked during needle opening and closing. Droplet sizes tended to be small on the edge of spray. The near-nozzle spray angle taken from the microphotographs was time-dependent, even though it increased with gas-to-liquid density ratio as expected. The near-nozzle spray angle was the greatest on the initial stage and decreased to a relatively constant value after about one third of the total injection duration regardless of the ambient gas conditions, even in the near-vaccum condition. The wider near-nozzle spray angle in the early stage is due to the flow characteristics inside the nozzle rather than aerodynamic interactions. However, once the spray was established, aerodynamic interactions are essential in the near-nozzle atomization.
A Study on the Gas Exchange Characteristics of Intake and Exhaust Systems in the Gasoline Engine
Transactions of the Korean Society of Automotive Engineers, volume 2, issue 4, 1994, Pages 112~119
This study is investigated into the dynamic effect of the manifold configuration during the gas exchange processes using both simulation and experiment, In theoretical study on the flow analysis, the characteristic method is applied to solve the compressible unsteady flow equation, involving the several steady flow boundary conditions. In order to excute the engine experiment efficiently, a data acquisition system is configured by using A/D converter and PC. Good results which coincided experimental data with simulation output were obtained, and it shows that this simulation method can be applied to obtain the optimal design parameters in the intake and exhaust systems.