• Composites Research
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• v.16 no.4
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• pp.22-28
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• 2003

This article deals with the manufacture and test results of asbestos-free friction material for Aluminium at toy disk. In order to obtain optimum formulation, various formulations of fibres, matrix, modifiers, fillers, etc were designed and evaluated. The constant friction and brake dynamometer tests were performed to know weak and strong point for each friction material. The C21 formulation of various tested formulations exhibited superior friction constant(0.38∼38), fade rate (18%) by JASO C406 test mode and maximum wear 1.6 mm. disc wear 0.08 mm by JASO C427 test mode. The surface morphology of AL alloy disk(before and after test) was observed by Scanning Electron Microscope(SEM) and Image Analyzer.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1401-1407
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• 2002

This paper represents an investigation of the vehicle-to-vehicle distance control system using Hardware-in-the-Loop Simulation(HiLS). Control logic is primarily developed and tested with a specially equipped test vehicle. Establishment of an efficient and low cost development tool is a very important issue, and test vehicle approach is costly and time consuming. HiLS method is useful in the investigation of driver assistance and active safety systems. The HiLS system consists of a stepper motor for throttle control, a hydraulic brake system with an electronic vacuum booster, an electronic controller unit, a data logging computer which are used to save vehicle states and signals of actuator through a CAN and a simulation computer using mathematical vehicle model. Adaptation of a CAN instead of RS-232 Serial Interface for communication is a trend in the automotive industry. Since this environment is the same as a test vehicle, a control logic verified in laboratory can be easily transferred to a test vehicle.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.154-162
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• 2004

In this study, a mathematical model for analyzing the shifting transients of the passenger car with an automatic transmission is proposed. The proposed model comprises a power transmission system and a vehicle system, which are coupled. In order to extract the modeling parameters, on-road car test is carried out. The model is composed of a detailed powertrain, an engine/AT housing, a simplified suspension system, tires and a vehicle body model. On the test, the vehicle accelerations and pitch ratio are measured by using accelerometers and a gyro sensor. The speeds, the brake signal, and the throttle position are taken from sensors which already exist in the vehicle. Considering natural ftequencies, which is calculated from the measured accelerations, and the characteristic equation, vehicle model parameters are identified. Dynamic behaviors during upshift or downshift are simulated using the proposed vehicle model. By comparing and analyzing the simulation result and on-road car test data, the vibration of the Engine/AT housing influences the shifting transients. The effect of model parameters are also studied. Among model parameters, the location of engine mountings influences the vibration of the vehicle body.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.1
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• pp.10-16
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• 2009

Automatic power transmission systems consisted of a torque converter and several planetary gear sets, clutches and brakes are controlled by a hydraulic shift control circuit and an electronic transmission control unit. The hydraulic circuit serves for the operation of the torque converter and lubrication oil supply of the transmission system as well as for the actuation of clutches for the automatic gear shift. The complicated hydraulic control circuit constructed by many spools, solenoids, orifices and flow passages are integrated into one small valve block and it is powered by one hydraulic pump. In this paper, a test equipment was developed to measure the oil consumption of each component at various wide operating conditions. Test data about 730 sets acquired from five test items are analyzed and discussed on the oil capacity of the circuit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.483-488
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• 2013

The psychoacoustic quality of ABS is now considered more important than before as the focus of recent ABS function is expanded to basic function from typical emergency function. Thus, the automotive parts manufacturing companies are actively working to improve NVH (Noise, Vibration, and Harshness) in ABS module. In terms of time, test place, and cost, however, it is very inefficient to have all the operating noise validation test in real vehicle configuration especially for partially improved ABS module. To contribute to reducing the development period and to grasping the improvements faster, this research presents the study of a correlation to predict ABS operating noise inside vehicle via HILS rig test. The regression equation in this paper was statistically drawn from using Minitab S/W, and based on that equation, the noise spectrum of vehicle interior was analogized.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.541-549
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• 2018

This paper deals with the braking dynamic behavior of diesel electric locomotive pulling domestic cargo and passenger vehicles. Friction coefficient, pneumatic pressure, and running resistance affecting the braking system were tested. For the friction coefficient, the Dynamo test was performed with reference to UIC 541-4. The results are analyzed by multivariate regression and the relationship between braking force and ititial velocity is presented. The pneumatic pressure were classified into service braking and emergency braking. In order to reflect the characteristics of the brake valve and piping, the pressure rising over time was measured in the vehicle. In order to reflect the external force acting on the vehicle, we carried out the test of EN 14067-4 and presented the second order polynomial formula on a running resistance. The running resistance test results were compared with other countries. The dynamic behavior of a diesel electric locomotive running on a straight flat track based on vehicle resources, friction coefficient, braking pressure, and running resistance is simulated using the time integration presented in EN 14531-1. The simulation results were compared and verified with the vehicle braking test results. The results of this study can be used to analyze the dynamic braking behavior of a train. Also, it is expected that various parameters affecting braking in vehicle design can be analyzed and used as basic data for braking performance improvement.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.103-109
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• 2014

This paper represents the s-cam manufacturing process with the high-carbon steel like S45C using laser welding system. Laser welding of the high-carbon steel is generally difficult because of hardening of the weld zone. Also, existing s-cam manufacturing process, electric resistance welding system, have some problems like increase of production and development cost. To solve those problems, we are introduced the laser welding system with the pre-heating system for precision welding of s-cam with separated shaft and cam part. S-cam manufactured with optimum laser welding conditions is verified the performance like tensile strength, torsional strength and fatigue test. Strength and fatigue test results are described.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.962-967
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• 2004

A bogie is the device that connects a car body and wheel sets of a rail vehicle. It is the critical component that determine:; the running safety, The bogie consists of a frame, suspensions, brakes and wheel sets. Various analyses including a numerical simulation using a finite element method, a static load test, a fatigue test, ai)d r running test should be carried out to design the bogie. However cracks have been found at some end beams of the bogies mounted on the freight cars running with the high speed. The cracks of the end beam results in deterioration of the brake performance an the running safety, A new design has been suggested to solve this problem by ROTEM company and it's performance has been tested in this paper. Numerical simulations and dynamic tests are carried out to figure out the causes of cracks in the conventional bogie, and the vibrational characteristics of the improved bogie are compared with those of the conventional one.

• Journal of ILASS-Korea
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• v.27 no.3
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• pp.155-160
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• 2022

Recently, major developed countries have strengthened automobile fuel efficiency regulations and carbon dioxide emission allowance standards to curb climate change caused by global warming worldwide. Accordingly, research and manufacturing on electric vehicles that do not emit pollutants during actual driving on the road are being conducted. Several automobile companies are producing and testing electric vehicles to commercialize them, but it takes a lot of manpower and time to test and evaluate mass-produced electric vehicles with driving mileage of more than 300km on a per-charge. Therefore, in order to reduce this, a simulation model was developed in this study. This study used vehicle information and MCT speed profile of small electric vehicle as basic data. It was developed by applying Simulink, which models the system in a block diagram method using MATLAB software. Based on the vehicle dynamics, the simulation model consisted of major components of electric vehicles such as motor, battery, wheel/tire, brake, and acceleration. Through the development model, the amount of change in battery SOC and the mileage during driving were calculated. For verification, battery SOC data and vehicle speed data were compared and analyzed using CAN communication during the chassis dynamometer test. In addition, the reliability of the simulation model was confirmed through an analysis of the correlation between the result data and the data acquired through CAN communication.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.788-794
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• 2019

Recently, global climate change caused by greenhouse gases has emerged as a significant air-environmental problem. Technical innovation in response to this phenomenon is ongoing, with an emphasis on the environmental impacts of unusually high temperatures and unexpected heavy rainfall. In this study, we investigated the effects of temperature change on air pollution for a concomitant rapid temperature increase. The test conditions include loading from 0 % to 100 % at 1400 rpm, 1600 rpm, and 1800 rpm for a change in the intake air temperature of a marine diesel engine from 20 ℃ to 50 ℃. The experimental results revealed that CO and HC decreased slightly, whereas the brake specific fuel consumption, NOx, and PM increased slightly when the intake air temperature changed. In addition, it was determined that the combustion temperature did not change significantly.