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Technical Paper

A Study on NVH Performance Improvement of TPE Air Intake Hose Based on Optimization of Design and Material

2019-06-05
2019-01-1491
Environmental regulations and fuel economy regulations on automobiles have been tightened recently. To counter this regulation, the global automobile industry is focusing its capabilities on weight reduction and continuously expanding and applying the fuel efficient turbo engine. However, with turbo-engine, turbulence occurs in the wheels of the turbochargers rotating at tens of thousands to hundreds of thousands of rpm, resulting in airflow noise. This noise is transmitted indoors through the air intake system, greatly weakening the vehicle's competitiveness. Therefore, in the case of turbo-engine, it is essential to ensure the high frequency noise reduction performance of the air intake system. The air intake system consists of an air cleaner, an air filter, an air intake hose and an air duct. The air flow noise of turbo-engine is mainly the emission noise emitted through the walls of the air intake system.
Technical Paper

Extensive Correlation Study of Acoustic Trim Packages in Trimmed Body Modeling of an Automotive Vehicle

2019-06-05
2019-01-1511
In the automotive sector, the structure borne noise generated by the engine and road-tire interactions is a major source of noise inside the passenger cavity. In order to increase the global acoustic comfort, predictive simulation models must be available in the design phase. The acoustic trims have a major impact on the noise level inside the car cavity. Although several publications for this kind of simulations can be found, an extensive correlation study with measurement is needed, in order to validate the modeling approaches. In this article, a detailed correlation study for a complete car is performed. The acoustic trim package of the measured car includes all acoustic trims, such as carpet, headliner, seats and firewall covers. The simulation methodology relies on the influence of the acoustic trim package on the car structure and acoustic cavities. The challenge lies in the definition of an efficient and accurate framework for acoustic trimmed bodies.
Technical Paper

A Study of Design Methodology to Develop Improved Door System of a Vehicle

2019-04-02
2019-01-0616
This research paper is about a systematic design methodology used to develop improved door system of a vehicle. With a variety of engineering analyses, a new structural design was derived and optimized. The previous door system required improvement of the following problems. First, the lower quality of a door system especially causes the performance degradation such as NVH. But it is difficult to have a robust structure because of the limitations of structural design and manufacturing technologies. Second, for a lightweight vehicle, it is necessary to construct a structure for saving weight while ensuring equal performance. Third, a structure for improving the openness and the visibility through the door is required for the convenience. An optimization structure capable of minimizing the door is needed. In order to solve these problems fundamentally, it was needed to design a new structure that considered all of these from the basic level in the following steps. Step1.
Technical Paper

Development of Ultra-Stable Cu-SCR Aftertreatment System for Advanced Lean NOx Control

2019-04-02
2019-01-0743
The integration of SCR catalyst into diesel-particulate filter (SDPF) may be one of most viable ways to meet upcoming stringent emission regulations with new test protocols such as Worldwide harmonized Light vehicles Test Cycles (WLTC) and Real Driving Emissions (RDE) requirements. The chabazite-structured SSZ-13-based catalysts enabled the wide implementation of urea-SCR technology for mobile applications due to their robust thermal stability up to 750℃ compared to the thermally unstable ZSM-5-based technologies. However, the thermally stable Cu-SSZ-13 catalyst starts collapsing its active unique structure at 850℃, where the SCR catalyst on SDPF can possibly be exposed during filter regeneration under a drop-to-idle (DTI) condition. Therefore, more durable SCR catalysts that survive under higher temperatures have been strongly desired in automotive industry. Recently, we found Cu-exchanged high silica LTA revealed an excellent hydrothermal stability.
Technical Paper

Effects of Bore-to-Stroke Ratio on the Efficiency and Knock Characteristics in a Single-cylinder GDI Engine

2019-04-02
2019-01-1138
As global regulations on fuel economy and CO2 emission are getting stringent, development of high-efficiency SI engine is now more urgent than ever before. Along with advanced techniques on friction reduction, automakers endeavor to decrease bore-to-stroke ratio (B/S) to reduce the heat loss and enhance the fuel conversion efficiency. In this study, the effect of B/S was investigated in aspects of efficiency and knock characteristics using a single-cylinder 0.5L LIVC (late intake valve closing) GDI engine. Three B/S ratio (0.68, 0.83 and 1.00) were tested under the same mechanical compression ratio of 12:1. The head tumble ratio was maintained at the same level to solely investigate the effect of geometrical change of B/S. In addition, as the engine was equipped with dual CVVT system, the optimization on valve timings was conducted to fully exploit the potential of each geometry.
Technical Paper

A development of the model based torque feedback control with disturbance observer for electric power steering system

2019-04-02
2019-01-1233
Electric Power Steering (EPS) control algorithm needs to meet both functional requirements and stability, because a driver interacts with the vehicle using steering system. First, it should make natural steering feeling. Second, it should ensure stability against deterioration of hardware. In order to meet these requirements, conventional control algorithms are designed with a stabilizing compensator and an assist torque map which is a one-to-one map between driver torque and assist motor torque. However, It is hard to tune parameters for satisfy both steering feel and stability because these things interact with each other. So, this paper supposes a torque feedback control algorithm to get independence between steering feel and stability. This paper presents a torque feedback control algorithm to improve steering feel and robustness against deterioration of hardware for EPS system.
Technical Paper

Improvement of Steering Performance using Steering Rack Force Control

2019-04-02
2019-01-1234
In recent years, steering performance has been improved considerably. Yet there are still complaints about steering feel, especially feedback performance on the road. The existing logic is not focused on steering performance. Therefore, it has a limitation in improving the steering performance. In addition, the steering system has friction and inertia due to the operating structure. this is felt to the driver by friction feeling and inertia feeling. As a result, the steering feedback performance deteriorates. In this study, the following steps are developed to develop new logic. First, The analysis of the steering system determines the key factors that affect the steering fell of the driver and defines the ideal steering system. To implement this ideal steering system, a rack-based feedback control is proposed. Secondly, The observer of rack force was designed to estimate the rack force. In general, the rack force estimator is estimated using the driver's torque, assist torque, etc.
Technical Paper

The Development of a NOx Reduction System during the Fuel Cut Period for Gasoline Vehicles

2019-04-02
2019-01-1292
In general, vehicles do not need to make power from engines in deceleration periods. Therefore, fuel cut-off mode can be applied in these periods to improve fuel efficiency. However, during the fuel cut-off periods, a large amount of fresh air flows from the engine into the catalytic converter equipped with the car because there is no combustion. So, the catalytic materials in the converters are changed into oxidized atmosphere. Eventually the efficiency for the NOx purification of catalytic converter rapidly deteriorates and catalytic converters cannot purify the NOx emitted immediately after the fuel cut-off. So, the conditions of fuel-cut off entries have no choice but to be strict for the cars which should meet stringent regulations such as SULEV 30. This strategy is not good for fuel efficiency. In this study, NOx emission process at this period was analyzed microscopically. Additionally, in order to reduce it, new concept of catalyst had been developed.
Technical Paper

Development of an Automated Seat Dimension Evaluation System

2019-04-02
2019-01-0401
The dimensions of an automobile seat are important factors affecting a driver’s seating comfort, fit, and satisfaction. In this regard, seat engineers put forth tremendous efforts to evaluate the dimensions of a product seat until the dimensions are consistent with the design reference in a computer aided design (CAD). However, the existing evaluation process is heavily reliant on seat engineers’ manual tasks which are highly repetitive, labor intensive, and time-demanding tasks. The objective of this study is to develop an automated system that can efficiently and accurately evaluate seat products by comparing estimated seat dimensions from a CAD model or a 3D scan model. By using the developed system, the evaluation time for comparing 18 seat dimensions on CAD and scan models has been substantially reduced to less than one minute, which is 99% time saving compared to two hours in the manual process.
Technical Paper

Measuring the Displacement of a Vehicle Body with an Optical Measuring System (Motion Capture)

2019-04-02
2019-01-0393
The 3D measurement of a body displacement on a moving vehicle is a quite challenging process. Well-known displacement measuring device such as a dial gauge and strain gauge can measure the displacement in only limited areas. An accelerometer also can estimate body motion but it has an accumulated error and a bias issue for an acquisition of displacements. However, an optical measuring (Motion Capture) method which uses markers and multiple cameras can read 3D coordinates directly and carry out those measurements well. In this paper, first, we determined how to extract a body displacement from global motion. Then we suggested a combining measurement methodology which uses a motion capture and an accelerometer simultaneously. Though it has failed to compensate each result and exact displacement, we showed an accuracy comparison between a motion capture and an accelerometer to measure a displacement along this process.
Technical Paper

A Development of the Holographic Lighting

2019-04-02
2019-01-0846
Automotive lighting perform a function to inform the position and behavior of the vehicle. It also represents a specific design identity of the vehicle or brand identity. Recently it implements the unique three-dimensional effect while using LED. However, a number of LEDs and complex form of the lens shape have to be applied, resulting in the size, weight and cost increase. In this study, holographic technology is applied as another method to realize 3D effect. The hologram uses the coherence of light and records the interference fringe generated by the object beam reflected by the object and the reference beam on the hologram film. At the time of reconstructing, the film is irradiated with only the reference beam to realize a three-dimensional image. The optical system using a hologram was consists of hologram film, a light source and optical components (reflection surfaces) for irradiating the reference beam at an angle to the film.
Technical Paper

The Development of Gear Tooth Micro Geometry Analysis Method for the Transmission Gear Noise Robustness

2019-03-25
2019-01-1414
Transmission error has been well known as the main source of excitation about transmission gear whine noise. To minimize transmission error in the gear system, various analysis methods have been studied and applied for long time. Many researchers were focused on gear micro geometry to achieve the low level of transmission error. But, if the gear is misaligned by several factors such as clearance and manufacturing tolerance error, then the gear noise can rapidly and unexpectedly be increased. To overcome this problem, this new analysis method has been developed and introduced. A transmission system simulation model was constructed, which considers various factors of transmission components such as clearance, stiffness and so on. The deformation and vibration characteristics of finite element models were validated by making comparison with frequency response function experiment.
Technical Paper

A Development of the Prediction and Optimization Tool for Wiper High Speed Performance

2019-03-25
2019-01-1417
In this paper, we focused on the robust wiping performance of high speed driven condition as an important situation for vehicle safety. Frist, we selected appropriate wiper performance parameter to accurately predict its ability not only systematic point but also vehicle point. Second, we obtained parameter sensitivity of wiper high-speed performance using DFSS technique. Third, we developed prediction and optimization tool using commercial program; Excel and Visual Basic. Finally, we improved our tool to compare vehicle test and then modified prediction coefficient for the accuracy of tool. Thus, we proposed a systematic tool to predict wiping performance in high speed vehicle, and successfully obtained efficiency when we developed the new project’s wiper performance.
Technical Paper

A Study of the Half Order Modulation Control for Diesel Combustion Noise by Using Model Based Controller Design

2019-03-25
2019-01-1416
This model based investigation is carried out in order to control the half order modulation for diesel engines using by virtual calibration approach and proposes a feedback control strategy to mitigate cylinder to cylinder imbalance from asymmetric cylinders torque production. Combustion heat release analysis is performed on test data to understand the root cause of observed cylinder to cylinder pressure variations. The injected fuel variations are shown to cause the observed pressure variations between cylinders. A feedback control strategy based on measured crank shaft position is devised to control the half order modulation to balance the combustion pressure profile between cylinders. This control strategy is implemented in Simulink and is tested in closed-loop with the diesel engine model in AMESim. The closed-loop performance indicates that the half order modulation is considerably improved while having minimal impact on the fuel consumption.
Technical Paper

Target Setting for the Stiffness of Local Mounting Area in the Vehicle Body for NVH and R&H

2019-03-25
2019-01-1418
Performance criterion of local stiffness in BIW(Body in White) for NVH(Noise, Vibration, and Harshness) and R&H (Ride and Handling) are presented in this study. A process to develop the local stiffness of the vehicle body has been established for the performances. For handling performance, not only suspension bush stiffness but local stiffness in BIW structure is important. However, there is no good standard to describe handling performance using BIW local stiffness. In this paper, a new evaluation standard for local stiffness in BIW is developed and verified considering actual vehicle driving condition for handling performance. Also, new evaluation process regarding local stiffness in BIW for vibration transmissibility is presented. The new process is developed considering optimal relation between connecting bush stiffness and BIW local stiffness. It is shown that the interior noise of the vehicle is reduced by applying the evaluation process, which is verified through several cases.
Technical Paper

Study on Basic Principles of Operation Noise of Wiper System on Vehicle

2019-03-25
2019-01-1421
The wiper system consists of a motor, linkage, arm, and blade, which provides a clear front view to the driver by removing rain, snow, and foreign matter from the windshield glass. It is a system component that requires a robust design to meet system rigidity, scrubbing performance, and operating noise to any external conditions to provide the driver with a front view. In recent years, however, customer complaints about wiper noise have increased as automobile engine and noise levels have decreased. Based on the analysis of wiper noise, this paper presents quantitative judgment criteria for various wiper noises. In addition, we predict the change of wiper noise to environmental factors through the sound field analysis and propose the solution.
Technical Paper

The Study of Optimization of Sliding Door Effect

2019-03-25
2019-01-1425
A sliding door system is one of the vehicle door types, which is generally applied to the MPVs. The Sliding door is contains three rails (an upper, a center, and lower rail), which are mounted on body structure, and three rollers (the upper roller, the center roller, Lower roller), which are mounted on the sliding door side. The system is different from a swing door, rotated by hinge axis. To set up sliding door layout for better performance, predict operating force is one of the main factors, But The door moving trace is on three-dimension, hard to calculate and predict. So in this study, it is an object to analyze the impact between the main factors affecting the performance of the closing and open performance and the sliding door through the study formula and a layout scheme for ensuring the best operating performance of the sliding doors.
Technical Paper

Smart Engine Control Strategy for the Fuel Efficiency Improvement via Understanding the Unique Behavior of TWC

2019-03-25
2019-01-1406
The worldwide fuel economy compliance level has been tightening, at the same time, LEV-III/Euro-6d/China-6/BS-6 regulations for NMOG and NOx emissions are being introduced or already effective. Therefore, intensive research effort has been conducted in order to improve the fuel efficiency of passenger cars and reduce exhaust emission. In response to these demands, turbocharged gasoline direct injection (TGDI) engine is being introduced for gasoline vehicles in consideration of fuel efficiency improvement, high output and driving performance compared to naturally aspirated (NA) engine. However, due to its larger thermal mass from the turbo hardware in the exhaust, it suffers from the cold-start emission. The main hazardous gases emitted from gasoline vehicles are CO, HC and NOx, and a three-way catalyst (TWC) is installed for the purification of these harmful emissions.
Technical Paper

A Study on Automated Tuning of the Head Gasket Coolant Passage Hole of the Gasoline Engine Cooling System Using Optimization Technology

2019-03-25
2019-01-1411
Tuning the size and position of the cooling water holes in the head gasket during engine cooling system development is generally positioned at the final stage of the cooling system hardware design. Until now, the gasket hole tuning operation was dependent on the case study through repetitive CFD analysis. In this process, there was a difference in the optimization level by know-how and expertise of the person in charge. In this study, a gasket hole tuning technique was developed using optimization algorithms to improve the level of optimization. First, select factors and perform screening using the DOE(Design Of Experiments) method, and then find the optimal gasket hole size and arrangement through the optimal design process based on the results of the CFD analysis planned by DOE.
Technical Paper

Development of Surfactant-Free Anti-Fogging Coating for Automotive Headlamps

2019-03-25
2019-01-1439
Recently, the design of automotive headlamps has become diversified and complicated according to customer needs. Hence, structural complexity of the headlamps has also increased. Complex structure of the headlamps inevitably causes a disturbance in air circulation. For this reason, inadvertent micro-sized water droplets, called fogging, are condensed on the inner surface of headlamp lens due to temperature difference between the inner and outer lens surfaces. To circumvent fogging inside of the headlamp lens, an anti-fogging coating is indispensable. Conventionally, diverse surfactants have been adopted as substantial material for the anti-fogging coating. However, the usage of the surfactants causes undesirable side effect such as water mark arising from vapor condensation, which is an important issue that must be fully resolved. In this study, we developed an innovative anti-fogging coating material without using conventional surfactant.
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