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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 4, Issue 6 - Dec 1996
Volume 4, Issue 5 - Sep 1996
Volume 4, Issue 4 - Aug 1996
Volume 4, Issue 3 - May 1996
Volume 4, Issue 2 - Mar 1996
Volume 4, Issue 1 - Jan 1996
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Experimental Study for Ferrofluid Couette Flow between Two Coaxial Spheres
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 1~9
This study investigated torque characteristics for Couette flow experimentally under circumstaces that ferrofluids were between two coaxial spheres. Torque measurement was obtained for the situation where the inner sphere was rotating while the outer sphere was kept stationary. The magnetic field was imposed on the fluid, using a bar magnet which was inserted in the inner sphere. In the laminar flow region the torque increase when the magnetic field is applied and the critical Reynolds number is increased. However, in the transition regime, the effect of the magnetic field on the torque characteristics decrease as Reynolds number increases. The value of torque were the same as those of glycerine solution beyond the cirtical Reynolds number. We also made experimental equation which could obtain coefficient of torque within critical Reynolds number in terms of sphere spacing Reynolds number and magnetic properties of ferrofluid.
Performance Improvement of Clutch Actuating Hydraulic Control System at Semi-Automatic Transmission for Construction Vehicles
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 10~21
In this study, as a strategy to improve shift characteristics, the authors developed a new style pressure modulator which can reduce shock torque during power shift by modulating the pattern of pressure increase in the cylinder for actuating the clutch. The remarkable merits of this new pressure modulator lie in its structural simplicity and durability, because the modulator is only composed of a poppet type valve and a few orifices. The usefulness of the new pressure modulator is confirmed by experiments and numerical analyses on a clutch control hydraulic system simplified for easy test. Also, the excellency of the transmission with the new pressure modulator is verified by experiments on a test bench for simulating the running power train of an excavator.
An Experimental Study of In-Cylindeer Flow Characteristics of a High Speed Direct Injection Diesel Engine
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 22~30
In-cylinder flow of a purpose-built small HSDI Hydra Diesel engine was investigated by laser Doppler velocimetry(LDV) during induction and compression processes. The flow was quantified in terms of ensemble-averaged axial and swirl velocities, normalized by the mean piston speed, at a plane located 12mm from the cylinder head and corresponding to the mid-plane of the diametrically-opposed quartz windows at an enigne speed of 1000rpm. The formation of toroidal vortices during the intake process and the evolution and decay of swirl motion during the compression process were observed. Turbulence at around TDC of compression became homogeneous and isotropic.
Experimental Study on Drag Reduction of Ground Vehicle Using a Rear-Spoiler
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 31~39
The effect of rear-spoiler attached at rear end of automobile trunk on the aerodynamic characteristics of a MIRA reference car model was experimentally investigated. For different shapes and positions(G/H) of the rear-spoiler, the aerodynamic forces on the automobile were measured at various flow speed(ReL). The effect of rear-spoiler on the wake structure behind the automobile was also investigated using flow visualization and hot-wire anemometer. The rear-spoiler modifies the near wake structure and decreases aerodynamic drag and increases driving stability compared with those of the conventional automobile without rear-spoiler. From the experimental results, rear-spoiler of airfoil shape installed at the position of G/H=0.084 shows the best aerodynamic performance.
Identification of Transfer Characteristics of Engine Noise by Multi-Dimensional Spectral Analysis
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 40~49
With the advance of the standard of living, the demand on automobile goes beyond the simple transportion equipment, therefore the interior noise reduction has been the important factor for improvement of the ride quality. Idling noise is a major vehicle characteristic determining occupant comfort. In the present research two approaches for noise source identification based on theory for multi-input system have been investigated. The concept of the frequency response function and the multi-dimensional spectral analysis were used to estimated the spectra of the noise source.
Conceptional Design and Basic Experiment of the Burner for the Particulate Trap System
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 50~60
We designed and developed the burner which would be adapted on the burner type diesel particulate trap system. The burner type particulate trap system consists of burner system to regenerate to ceramic filter, ceramic filter canister, system controller and etc. Many design factors which affect the performance of the burner system were discussed. We also investigated burner characteristics according to the operating parameters. Burned gas temperature could be controlled better by the 2nd air flow rate than the 1st one. As the space velocity increases, the axial and radial temperature gradients in the filter decreases.
An Estimation of Comfort on the Automobile Driver Seat Korean Anthropometric Experiment
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 61~72
In this paper, the driver seat comfort of eight automobiles was studied. The joint angles and anthropometric data of eleven subjects sitting on the seating buck were investigated using the instrument devices such as scale, goniometer, vernier calipers, protractor, Martin set. The joint angles of the most comfort posture were found by experiment and compared with previous studies. The anthropometric data of Korean(1992 year surveys) and American(1970∼1974 year) were applied to evaluate the driver seat layout of Korean automobile. The joint angles of the most comfort posture for eleven subjects were obtained with experimental results. The joint angles were agreed with reference angles. The driver seat layout was not suited to seat length and acceleratorseatpan forward distance in 5 percentiles female, pedal separation and seatpan-roof height in 95 percentiles male. Korean automobiles were not suited to seatpan length and steering wheelseatpan clearance, floor-roof height for American 95 percentiles male. The driver anthropometric dimensions were more suitable to middle size than small size automobiles.
Vehicle Tracing Method Using Adaptive High Order Correlation Analysis
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 73~82
Vehicle movement detection by high order correlation analysis of optical sensor array signals is introduced. The optical sensors observe the road which is assumed to be a non-uniform speckle-like texture. The measurement system is applicable to general robotic movement detection because : 1) It employs a non-contact measurement method, 2) The system can be made very compact, and 3) It enables approximation of the movement trace with a sequence of arcs instead of the conventional connection of simple line segments. In this work, we have looked into estimation of running trace of an autonomous vehicle by observing the ground pattern.
The Energy Absorption Characteristics of Thin-walled Rectangular Tubes
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 83~91
This paper investigates the energy absorption characteristics of thin-walled rectangular tubes. In the compact mode, the crushing process of a thin-walled tube is analyzed into 3 parts by the ratio of outward to inward fold length. The mean crush load and the half-wave folding length are determined by using minimum energy principle. The effective crush distance can be determined when half-wave folding length is known, and the number of folds is derived when crush distance is given. Thus when the crush distance is given, energy absorption capacity can be estimated with mean crush load and number of folds. And the theoretical value is proven experimentally.
Characteristics of the Air Flow Variation by Throttle Step Change in a Gasoline Engine
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 92~101
In a gasoline engine, the characteristics of air flow is very important not only for the design of the intake system geometry bout also for the accurate measurement of the induction air mass. In this study, an air flow rate measurement of the induction air mass. In this study, an air flow rate measurement was conducted by using the hot wire flow meter at the upstream of the intake port and the throttle. At the upstream of the throttle, the overshoot phenomena of the air flow rate by fast throttle opening were analyzed with choked flow. At the upstream of the intake port, the cylinder variation of the air flow rate and the difference between fast throttle opening and closing were showed during the unsteady state by the throttle step change. The results of this study can be used for the design of the throttle valve geometry and cylinder by cylinder control.
Modulated Fuel Feedback Control of a Fuel Injection SI Engine
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 102~111
For the air-fuel ratio control in a fuel injection SI engine, the Jump-Ramp control algorithm has been widely adopted by using the on/off type oxygen sensor. But the Jump-Ramp control method has limitation on treating the frequency and amplitude of the air-fuel ratio oscillation. This study suggests another feedback control logic named modulated fuel feedback control, which has a concept of pre-tuned air-fuel ratio oscillation. In the modulation method, the oxygen sensor output is not treated as on/off signal but as analog signal for feedback. By using the modulation method, the frequency and the amplitude of air-fuel ratio oscillation can be adjustable to some extent for improving the conversion efficiency of the Three-Way Catalyst. The result shows that the performance of the modulation method is better than that Jump-Ramp control method in reducing the amplitude of the air-fuel ratio oscillation as well as in increasing the frequency of the air-fuel ratio oscillation.
Prediction of Propagation Path for the Interface Crack in Bonded Dissimilar Materials
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 112~121
Applications of bonded dissimilar materials such as metal/ceramics and resin/metal joints, are very increasing in various industry fields. It is required to find crack propagation direction and path applying to the fracture mechanics on the bonded joint of dissimilar meterials. In this paper, crack propagation direction and path were simulated numerically by using boundary element method. Crack propagation angle is able to easily determine based on the maximum stress concept. Fracture tests of Al/Epoxy dissimilar materials with an interface crack are carried out under various mixed mode conditions by using the specimens of bonded scarf joints. It is found that the experimental results are well coincide with the analysis results of boundary element method.
A Study on the Adaptive Control of Spark Timing Using Cylinder Pressure in SI Engine
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 122~129
The spark timing is one of major parameters to the engine performance and emissions. The ECU controls the spark timing based on preset values, which are functions of load and speed, in most of today's automotive SI engine. In this system, the preset spark timing can be different from optimum value due to the deviations from mass production, aging effects and so on. In the present study, a control logic is investigated for real time adaptation of spark timing to optimal value. It has been found that crank angle of miximum cylinder pressure is one of the appropriate parameters to estimate the optimum spark timing throught experiment. It has also been observed for spark timing convergence by variation of engineering model factors. The simulation program including engineering model for cycle by cycle variation of combustion is developed for surveying spark timing control logic. It is also shown that simulation results reflect experiment outputs and reasonableness of spark timing control logic for crank angle of maximum cylinder pressure.
Numerical Simulation of Unsteady Flow Field behind Widely-Spaced Co-axial Jet using Random Vortex Method
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 130~138
The transient incompressible flow behind the widely-spaced co-axial jet is numerically simulated using the random vortex method(RVM). This numerical approach is based on the Lagrangian approach for the vorticity formulation of the unsteady Navier-Stokes equations, utilizing vortex elements to account for the convection and diffusion processes. The effects of the mass flow rate of an annular air jet and a central fuel jet on the co-axial jet flow dynamics is investigated. To validate the present procedure, the numerical results are compared with the available experimental data the present procedure, the numerical results are compared with the available experimental data in terms of the centerline and off-centerline profiles of the mean axial velocity. Discrepancies between the RVM results and the measurements are discussed in detail.
Numerical Computations of Turbulent Flow in a
Curved Duct Using a Modified Extended
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 139~146
tuebulence model modified by considering the streamline curvature effect and standard
turbulence model have been applied for three dimensional analysis of turbulece flow in a
curved duct. By comparision of the results with the experimental data, the modified extended
model gave closer agreement with experimental data than the results from standard
model owing to an extra time scale of the production rate and parameter describing effects of streamline curvature included in the dissipation rate equation.
A Study on the Chamical and Physical Characteristics of Ultrasonic-Energy-Added Diesel Fuel
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 147~155
This study investigated the characteristics of ultrasonic-energy-added diesel fuel. We compared the characteristics used H-NMR spectrum, FT-IR spectrum, viscosity and surface tension between conventional diesel fuel and ultrasonic-energy-added diesel fuel. The result are obtained as follow : We knew that ultrasonic energy result to reduce BI and weaken viscosity and surface tension. Also, the ultrasonic energy caused to reduce aromatics Ha and increase Alkanes Hγ. The effect of ultrasonic-energy-added dieselfuel was principally caused by change of chemical structures and a physical characteristics.
Combustion Characteristics of Methane-Hydrogen-Air Premixture(II)
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 156~167
The present work is a continuation of our previous study to investigate the effects of parameters such as equivalence ratio, hydrogen supplement rate and initial pressure on combustion characteristics in a disk-shaped constant volume combustion chamber. The main results obtained from the study can be summarized as follows. The flames in near stoichiometric mixture of methane-air are propagated with a spherical shape, but in excess rich or lean mixtures are propagated with a elliptical shape. And, they are changed to an unstable elliptical shape flame with very regular cells by increasing the hydrogen supplement rate. Also, flame is sluggishly propagated at increased initial pressure in combustion chamber. Volume fraction of burned gas and flame radius as the combustion characteristics are increased by increasing the hydrogen supplement rate, especially at the combustion middle period, but then are slowly increased by increasing the initial pressure.
A Study on the 4WS Control Method with the Effect of Steering Wheel Angular Velocity
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 168~175
Except the collision avoidance performance related to the rapid lane change, the 4WS vehicle has better dynamic stability and handling performance than the conventional 2WS vehicle which has close relation with the driver's safety, a 4WS conrol method with the effect of steering wheel angular velocity is proposed based on the fact that the driver steers abruptly the steering wheel to avoid the collision. And the effects of the proposed 4WS control method are investigated on the dynamic stability and handling performance by using the ISO lane change test code.
A Study on the Characteristics of Flow with Polymer Additives
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 176~186
The phenomena of drag reduction using small quantities of a liner macromolecules has attracted the attention of many experimental investigations. On the other hand drag reduction in two phase flow can be applied to the transport of crude oil, phase change system such as chemical reactor, pool and boiling flow, and to flow with cavitation which occurs pump impellers. But the research on dragreduction in two phase flow is not sufficient. The purpose of the present work is to evaluate the drag reduction by measuring pressure drop, void fraction, mean liquid velocity and turbulent intensity whether polymer additives a horizontal single and two phase system or not. Flow pattern of air-water two phase flow was classified by electrical conductivity probe signal. Velocities and turbulent intensities of signal were measured simultaneously with a Hot-film anemometer.
Numerical Analysis on the Performance for Automobile Heat Storage System Using Phase Change Materical
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 187~198
In this study, the performance of an automobile heat storage system using PCM is numerically simulated. For the analysis of system performance. The phase-change of the PCM and the transient forced convective heat transfer for the HTF are considered simultaneously as a conjugate problem. The phase-change behavior is effectively analyzed using a concept of thermal resistance. From the correlations of phase change rate and heat transfer due to the variations of flow rate of HTF around PCM, the automobile heat storage system performance is predicted. The present results amy be used as the fundamental information for the design of automobile heat storage system.
Characteristics of the Internal Flow in the Scaled-Up Fuel Nozzle
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 199~210
The measurements of velocities of internal flow in a scaled-up nozzle were made by laser Doppler velocimetry in order to clarify the effect of internal flow on the characteristics of fuel spray. The investigated length to diameter ratio(L/d) of the orifice were 1, 3, 4, 5 and 8, and inlet radius to diameter ratio(r0/d) were 0 and 0.5. Mean and fluctuating velocities and discharge coefficients were obtained at various Reynolds number ranging between 15,000 and 28,000, and L/d ranging between 1 and 8 in sharp and round inlet nozzle. The turbulent intensity and turbulent kinetic energy at exit in a sharp inlet nozzle were higher than that in a round inlet nozzle. For sharp inlet nozzle, fluctuating velocities near exit were decreased with increasing L/d.
The Behavior of Impinging Spray by Piston Cavity Geometry
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 211~219
In a small high-speed D. I. diesel engine, the injected fuel spray into the atmosphere of the high temperature is burnt by go through the process of break up, atomization, evaporation and process of ignition. These process are important to decide the emission control and the rate of fuel consumption and out put of power. Especially, in the case of injected fuel spray impinging on the wall of piston cavity, the geometry of piston cavity gives great influence the ignitability of injected fuel and the flame structure. Ordinary, the combustion chamber of driving engine have unsteady turbulent flow be attendant on such as the change of temperature, velocity and pressure. So the analysis of spray behavior is difficult. In this study, the spray was impinged on the wall of 3 types of piston cavity such as Dish, Toroidal, Re-entrant type, in order to analyze the combustion process of impinging spray precisely and systematically. And hot wire probe was used for analyze non-steady flow characteristics of impinging spray, and to investigate the behavior of spray, the aspects of concentration c(t), standard deviation σ(t) and variation factor(vf) was measured with the lapse of time.
Effects on Combustion Characteristics Induced by Ignition Timing and Shape of Passagehole in a IDI Type Constant Volume Combustion Chamber
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 220~231
In this research, we use IDI type constant volume combustion chamber which may make up stratified combustion to construct the design back data of lean-burn engine. Some experiments are conducted by the passagehole angle in the adapter of main chamber and sub-chamber. The effects on the combustion characteristics according to the ignition timing are investigated. The used fuel is methanol prospective for alternative fuel. Fuel is injected under 10.78MPa using solenoid and accumulator. As the results of the experiment, combustion characteristics reveals that ignition timing, passagehole angle and shape greatly effects on. Lean inflammability limit is extended to 0.45 in equivalence ratio.
A Study on the Improvement of Volumetric Efficiency by the Resonators for the 4-Cylinder SI Engines.
Transactions of the Korean Society of Automotive Engineers, volume 4, issue 3, 1996, Pages 232~242
In this study, the simulation program for the prediction of volumetric efficiency of the internal combustion engine by the resonator has been developed, when the resonator is mounted on the intake system of 4-cycle SI engines for the improvement of volumetric efficiency. The experimental work has also been carried out for the verification of the program, and it is found that the result of calculation by the simulation program fits qualitatively well with that of experiment. To get the optimal mounting position of resonator on the intake system, the influence of the variation of dimensions of resonator such as neck length, volume and neck diameter were examined by the numerical calculation of the program in advance and the results were compared with the experiments. It is found that the position which is departed 150cm from plenum chamber is better than any other positions, and the average amount of the increase of volumetric efficiency is about 2∼3%