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Technical Paper

A Study on the Modeling Technique of Airbag Cushion Fabric

The decision of linear elastic Young's Modulus and other properties of airbag cushion fabric are difficult mainly due to the non-linearity of stress-strain curve of cushion fabric. Especially for the tensile test of cushion fabric, the different test methods add complexity in determining proper linear elastic modulus. Poisson's ratio has been generally assumed as a mean value of steel's one and rubber's one in the modeling of airbag cushion in previous researches (1). In this study, airbag droptower test and simulation were performed for example to find the proper material properties of airbag cushion fabric such as Young's Modulus, Poisson Ratio, Permeability and Shear Modulus.
Technical Paper

A Study on the Modelling Technique for the Passenger Out-Of-Position Simulation

There was a regulation to reduce injuries caused by airbags for OOP (Out-Of-Position) impact loading conditions. Also, many tests are needed to meet the regulation regarding design variation. And the main effect of airbag design variable has not been well known. Therefore, numerical simulation modelling method and technique were required to reduce the test numbers and recommend the airbag design guideline for OOP condition. To establish modelling procedure for OOP situations in this paper, simulation model was built and correlated with test. Also, the body block test for airbag cushion correlation, a pendulum test for opening stiffness correlation of airbag door and low risk deployment static test using 3-year-old dummy for OOP simulation correlation were performed. And, airbag door and folding condition were evaluated using full factorial DOE (Design of Experimental) technique.
Technical Paper

A Study on the Muffling Method Using New Materials

Since the engine noise of a small portable single cylinder 2 or 4 cycle gasoline engine exceeds 100 dB (A), making the reduction of noise levels is very important. Conventional noise reduction measures have been to expend the pulse flow energy of the exhaust gas even at some sacrifice of engine performance, that is, resistance is introduced to lower the flow rate. Recently, we have developed a carbon fiber felt from coal tar pitch, which shows high resistance to oxidation and physically and chemically stable properties, and used it in the exhaust muffler and in the bottom of the engine crankcase, enabling the reduction of noise emitted from the engine package by approximately 3 dB (A). Compared with rock wool and glass wool, this carbon felt has the superior characteristics of (a) lower mass and (b) larger surface area per unit weight (1)*.
Technical Paper

A Study on the NOx Reduction of Urea-Selective Catalytic Reduction(SCR) System in a Heavy-Duty Diesel Engine

The selective catalytic reduction system has been known well so far in the reduction of NOx emission in diesel vehicles. This research focused to evaluate the performance of urea-SCR system in a heavy-duty diesel engine and was proceed in four steps. First, optimal urea injection conditions for system were developed. Second, optimal geometric conditions for a urea injection system were investigated by a numerical simulation technique. The simulation results contribute to determine the layout of engine test. Before performing engine test, SCR reactor was used to observe basic performance on SCR. This observation was made on effective NOx reduction according to gas temperatures, SVs (space velocity) and ARs (aspect ratio). Finally, the engine test is carried out based on results of above experiments.
Technical Paper

A Study on the NVH Problems Caused by the Additional Excitation Force of Propeller Shaft

The NVH performance is one of the most important concerns in vehicle development. For all-wheel drive (AWD) vehicles and rear-wheel (RWD) drive vehicles, prop shaft is a major transmission component which may cause various NVH problems. This paper focuses on the vehicle NVH problems caused by the second order excitation force of prop shaft. In order to control the NVH performance of the prop shaft efficiently and fundamentally, this work first studied the rotation kinematical characteristics of prop shaft. Then a rigid-elastic coupling model of vehicle driveline was built with the theory of multi-body dynamics. With this model, the sensitive factors that may affect the second order excitation force were investigated. This paper also describes a case study to verify the conclusions which are revealed from the theoretical calculation and the simulation.
Technical Paper

A Study on the Noise Generating Mechanism of a Fuel Injection Pump

This paper has clarified the noise generating mechanism on the BOSCH AD type fuel injection pump by using numerical and experimental analysis methods. The calculated vibration of each part has been verified to coincide well with the measured acceleration data. Based on the detailed analysis, the major noise source of the injection pump was found to originate from the tappet vibration caused by the steep pressure drop at the end of injection. After performing some parameter studies by using the simulation model, it turned out that some specifications of the injection pump influenced its sound power.
Technical Paper

A Study on the Noise Separation Method of Fuel Pump Using AI Model

It is very important to secure the purity of the sound source to improve the degree of development of the noise problem, which is one of the important factors in vehicle development. So far, to acquire only the noise of the component, which is a problem element in vehicle driving noise, the component is removed and driven to acquire the noise, or the method of denoising the noise of other parts has been used. However, the method of removing part takes a lot of time to remove the part, and when the noise of the removed part is acquired, it has a disadvantage in that it differs from the characteristics of the noise measured in the mounting state of the vehicle. In addition, the method of denoising may cause data loss due to the deformation of the sound source of the noise.
Technical Paper

A Study on the Optimal Design of Automobile Interior Plastic Parts (A-Pillar Trim) Considering Heat-Resistant and Mechanical Characteristics

Interior parts that are composed of plastic usually deform under various temperature conditions. It is necessary to obtain the material properties for an analysis of the thermal deformation under the heat cycle test. Specifically, creep data of plastic material was introduced for studying the time-dependent deformational behavior of the pillar trim in the heat cycle test. The time-hardening version of the power-law creep model was applied to account for the permanent deformation following the heat cycle test, which was verified through a comparison of the test results with the result of finite-element analysis for a simple model. In this study, a methodology was developed for the optimal design of the A-pillar trim in terms of the positions of the mounts. The analyzed results were used to approximate a function that was constructed by the response-surface method. Design procedures were repeated to minimize the thermal deformation at the areas of interest.
Technical Paper

A Study on the Optimal Design of IP Module Considering Performance of LRD A/BAG Deployment

The current advanced airbag regulation (FMVSS208) requires passenger cars and MPV either to have an automatic suppression system or to meet the LRD requirement on the passenger side. Recently, the car makers are choosing LRD requirement option and developing new LRD passenger airbag system. This paper presents a new methodology for improvement of airbag deployment using experimental and analytical research. The significant parameters were determined from statistical analysis of the experiment data. Basically, to deploy airbag normally, the ultra sonic knife or laser is used to cut the skin layer inside along with the gate line partially, so that deploying airbag can tear gate on instrument panel surface easily. As a result of the number of tests conducted at different conditions, this study was able to determine the range of relevant parameters.
Technical Paper

A Study on the Optimization of Body Structure for Rattle Noise by Exciting Woofer Speakers

With the recent development of technologies for interpreting vibration and noise of vehicles, it has become possible for carmakers to reduce idle vibration and driving noise in the phase of preceding development. Thus, the issue of noise generation is drawing keen attention from production of prototype car through mass-production development. J. D. Power has surveyed the levels of customer satisfaction with all vehicles sold in the U.S. market and released the Initial Quality Study (IQS) index. As a growing number of emotional quality-related items are added to the IQS evaluation index, it is necessary to secure a sufficiently high quality level of low-frequency speaker sound against rattle noise. It is required to make a preceding review on the package tray panel, which is located at the bottom of the rear glass where the woofer speakers of a passenger sedan are installed, the door module panel in which the door speakers are built.
Technical Paper

A Study on the Optimum Design of a Stiffening Plate for the Vibration Reduction of an Engine Block

The tests on running engines reveal that the vibration levels of an engine block are higher at the lower portion than the upper portion. The objective of this paper is to reduce the vibration levels of an engine block by the stiffening plates with minimum weight increase. The analytical modal analyses of an engine block and the stiffening plates made of aluminum and steel are performed by the Finite Element Method (FEM). The experimental modal analyses are also conducted and two results are correlated. In these validated modal model, an engine block and the stiffening plates are combined by the spring elements. The Component Mode Synthesis is used to obtain the natural frequencies and modes of the combined blocks. The iterative analyses are performed with varying thickness of the stiffening plates in order to design the optimum one which reduces the vibration levels of an engine block effectively with minimum weight increase.
Technical Paper

A Study on the Optimum Reduction of Required Brake Fluid Level for Improvement of the High Speed Continuous Brake Distance

The high speed continuous braking distance assessment is the worst condition for thermal fades. This study was conducted to investigate the relationship between fade characteristic and friction materials & brake fluid amount for improving braking distance. So, we used the dynamometer to measure the friction coefficient, braking distance and required brake fluid amount. Through the measurements, the research was carried out as follows. First of all, we studied the influence of friction coefficient about different shapes (chamfer shape, area of the friction material, number of slots) on the same friction material. Secondly, we knew the effects of braking distance by the shape of the friction material. Through these two studies, the shape of the friction material favorable to the fade characteristics was derived. Finally, we measured the amount of required brake fluid in caliper after 10 consecutive braking cycles through Dynamometer.
Technical Paper

A Study on the Performance Deterioration of SCR for Heavy-Duty Diesel Vehicles

In this study, a six litres displacement, commercial vehicle engine that meets the EURO-5 regulation was used to evaluate the durability and performance deterioration of the SCR system mounted on a heavy-duty diesel vehicle. ESC and ETC modes were used for emission test. Characteristics of emissions by SCR catalyst deterioration were investigated using mileage vehicles of 0 km, 120,000 km, and 360,000 km. EDS (Energy Dispersive X-Ray Spectroscopy) analysis on PM filters and CT scan to catalyst substrate were carried out in order to investigate the status of catalyst by each mileage. As a result, it was found that NOX, slipped NH3 as well as PM due to unreacted ammonia and urea increased as the mileage of the catalyst increased.
Technical Paper

A Study on the Performance and Emissions of HCCI Oxy-Fuel Combustion in a CFR Engine with Recirculated Carbon Dioxide

Stringent emission regulations and the anticipated climate change call for a paradigm shift in the design of the conventional internal combustion engines. One way to combat this problem is oxy-fuel combustion in which the combustion products are mainly water vapor and carbon dioxide. Water vapor can be easily separated by condensation and carbon dioxide is then easily captured and stored. However, many technical challenges are associated with this mode of combustion. There are many challenges facing oxy-fuel combustion before it find its way to commercial production especially for internal combustion engines. One such challenge is the relatively high temperature of the oxy-fuel combustion. A solution to this problem is the recirculation of the generated CO2 to moderate the in-cylinder temperature. Therefore, careful study of the effect of recirculating the CO2 back to combustion chamber is needed before the implementation of such a concept.
Technical Paper

A Study on the Performance of Air Suspension for Different Kinds of Rubber and Cord Materials Used in Rubber Tube

Recently, to enhance passenger comfort, air suspension systems with rubber tube have been replacing conventional coiled spring type suspension in automobile suspension systems. In this study, the optimum design of rubber and cord materials in rubber tube, aimed at improving the performance of the air suspension system, has been studied. To determine the optimum design, the study altered the fillers and antioxidants in CR (chloroprene rubber) compounds with good ozone-resistance properties, and changed the angles and thickness of the nylon cord. The study produced rubber tubes using cord-reinforced rubber composite materials, then analyzed and measured the resultant physical properties, microstructure, and dimensions. It also evaluated the load capacity, static and dynamic spring characteristics, outer diameter changes, and pressure changes in the loading, and determined the burst pressure of air suspension.
Technical Paper

A Study on the Performance of Guideway Bus Steering Control System

In this paper a computer simulation study on the effects of steering parameters on lateral dynamics of the guideway bus to contribute to a development practice of designing optimum steering control system are dealt with. A stability limit of vehicle lateral motion is analyzed and an emphasis is laid on the effects of moment of inertia of a conventional steering wheel and lateral elasticity of the guide rail which have proven to reduce the critical vehicle speed. It is pointed out conclusively that a normal bus equipped with additional simple guidance equipments can be guided smoothly on a simple guideway at adequately high vehicle speed.
Technical Paper

A Study on the Performance of Lubricating Greases for Electric and Hybrid Vehicle Applications

The automotive sector has always been closely connected with the lubricants industry, with the latter continuously developing new technologies, specs and products in order to address the evolution in this segment. Electrification represents a significant change in the major powertrains and, thus, it will inevitably affect the selection, development and market share of several types of lubricants, such as lubricating greases. The evolution of the EV/HV segment will increase the demand and the importance of lubricating greases for electric motors. New challenges for grease formulation may arise from the neighboring electric currents and electromagnetic fields and higher energy efficiency requirements. In this paper, the perspectives and the projected evolution of automotive e-mobility is reported and the subsequent influence on the main grease performance requirements are analyzed. Moreover, the alteration in the applications are examined.
Technical Paper

A Study on the Performance of the New Bumper System with Gas Tube

The car crash at low speed occurs most frequently and results in the highest rate of repairing cost. Especially, statistics shows that for full repair items of damaged vehicles there are the front bumper repair rate and rear bumper repair rate in 2000 year. Thus, many auto-parts manufacturers are paying keen attention to the safety of the passengers and currently developing the various types of bumper systems by applying the gas tube to the conventional bumper system (CBS) in order to improve the damageability in a low speed crash. On this study, in order to check the capability, damageability and repair ability of gas tube bumper system (GBS), RCAR (Research Council for Automobile Repairs) 15km/h 40% offset frontal crash test was adopted in low speed. As a result of study, GBS might need one more process production and assembling the gas tube. The total crash time and acceleration improved. 3 rooms 1 row GBS can improve the damageability and repair ability.
Technical Paper

A Study on the Possibility of Estimation of In-Cylinder Pressure by Means of Measurement of Spark Gap Breakdown Voltage

In-cylinder pressure of an IC engine is considered to be a major source of information about combustion process. It is a generally accepted method to obtain an in-cylinder pressure signal using a pressure sensor (transducer). In this paper, a different approach is presented. Information about the in-cylinder pressure can be obtained by measuring breakdown voltage across the spark-plug gap. A simple means for measurement of such voltage is developed. The breakdown voltage threshold depends on the density of the gas in the combustion chamber. A strong correlation between the measured breakdown voltages and in-cylinder pressure has been established.
Technical Paper

A Study on the Practicability of a Secondary Air Injection for Emission Reduction

In this study, feasibility tests of secondary air injection technology and lean A/F control technology were performed for LEV program using the FTP75 test on a 2.0 DOHC A/T vehicle. Second-by-second emissions and temperatures were evaluated. The temperatures of exhaust gas were measured at exhaust manifold, front of warm up, and the center of warm up converter. At first, amount of secondary air injection was determined with a bench aged warm up converter and a fresh UCC. And then, the performances of secondary air injection and lean A/F control strategy were compared with 80,000km vehicle aged converters(warm up converter, UCC). Both secondary air injection and lean A/F control technologies satisfied the ULEV regulation. This study shows that the lean A/F control strategy can be one of the potential technologies to meet the LEV/ULEV regulations without an active system that need a cost up.