Search Results

During the vehicle lifecycle, customers are able to directly perceive the outer panel stiffness of vehicles in various environmental conditions. The outer panel stiffness is an important factor for customers to perceive the robustness of the vehicle. In the real test of outer panel stiffness after prototype production, evaluators manually press the outer panel in advance to identify vulnerable areas to be tested and evaluate the performance only in those area. However, when developing the outer panel stiffness performance using FEA (Finite Element Analysis) before releasing the drawing, it is not possible to filter out these areas, so the entire outer panel must be evaluated. This requires a significant amount of computing resources and manpower. In this study, an approach utilizing artificial intelligence was proposed to streamline the outer panel stiffness analysis and improve development reliability.

With the trend of electrification and connectivity, more electrified parts and more integrated chips are being applied. Consequently, potential problems based on electro-magnetic could occur more easily, and interest on EMC performance has been rising according to the degree of electrification. In this paper, one of the most severe systems, cooling fan motor in terms of EMI, is analyzed and improvement methods are suggested for each type of cooling fan. Additionally, an optimized configuration of improvement method for EMC has been derived through analysis and study. Finally, verification and validation are implemented at the system and vehicle levels.

Recently, regulations on automobile emission have been significantly strengthened to address climate change. The automobile industry is responding to these regulations by developing electric vehicles that use batteries and fuel-cells. Automobile emissions are environmentally harmful, especially in the case of vehicles equipped with high-temperature and high-pressure diesel engines using compression-ignition, the proportion of nitrogen oxides (NOx) emissions reaches as high as 85%. Additionally, air pollution caused by particulate matter (PM) is six to ten times higher compared to gasoline engines. Therefore, the electrification of commercial vehicles using diesel engines could potentially yield even greater environmental benefits. For commercial vehicles battery electric vehicles (BEVs) require a large number of batteries to secure a long driving range, which reduces their maximum payload capacity.

The existing FCEV have been developed with only a few vehicle models. With the diversification of both passenger and commercial FCEV lineups, as well as the increasing demand for vehicle trailer towing, there is a growing need for high-capacity fuel cell stacks to be applied in vehicles. However, at the current level, there are limitations and issues that arise, such as insufficient power output and reduced driving speed. As a results, the importance of thermal energy management has been increasing along with the increase in required power. Traditional cooling performance enhancement methods have mainly focused on developing increased hardware specifications, but even this approach has reached its limitation due to package, cost and weight problem. Therefore, it is essential to develop a new cooling system to solve the increases in heat dissipation.

In order to align with net-zero CO2 ambitions, automotive OEMs have been developing increasingly sophisticated strategies to minimise the impact that combustion engines have on the environment. Intelligent thermal management systems to actively control coolant flow around the engine have a positive impact on friction generated in the power cylinder by improving the warmup rate of cylinder liners and heads. This increase in temperature results in an improved frictional performance and cycle averaged fuel consumption, but also increases the piston to liner clearances due to rapid warm up of the upper part of the cylinder head. These increased clearances can introduce piston slap noise and substantially degrade the NVH quality to unacceptable levels, particularly during warmup after soak at low ambient temperatures. Using analytical techniques, it is possible to model the thermo-structural and NVH response of the power cylinder with different warm up strategies.

Generally, the HVAC system of a vehicle is composed of Blower unit assembly and Heater unit assembly, and is located on the driver’s side of the dash panel. However, electric vehicles have far fewer parts than conventional internal combustion engine vehicles, so electric vehicles have large space in the engine room. This allows HVAC, which occupies large volume in the interior side, to be pushed in the direction of the engine room altogether, or by placing a part inside the engine room to make a slim cockpit and expand the interior space. However, this new structure, called the Split HVAC System, is mounted through the dash, allowing noise to pass through relatively easily. Since this adversely affects the NVH of an electric vehicle, it needs to be developed in terms of noise transmission. Therefore, in this paper, a study was conducted to predict the sound transmission loss of Split HVAC through an analytical method.

For making metal touch feeling and lighting simultaneously, selective electroplating is widely applied in button, panel and etc. in interior/exterior parts of automotive. In this paper, new selective electroplating with printing are suggested as an alternative manufacturing process of two shot molding, PC (Polycarbonate) and ABS (Acrylonitrile-Butadiene-Styrene). Manufacturing process of selective electroplating with printing is as follows: For preventing to plate metal layer in area of letter or symbol, masking ink is printed on parts, button, panel, etc., with electroplatable PC+ABS. After conventional electroplating process, the part has electroplated metal layer except for the printed area. It had been studied the composition of ink and PC+ABS for obtaining skip plating and light transmittance on printed area.

The woofer in a car should be large to cover the low frequencies, so it is heavy and needs an ample space to be installed in a passenger car. The geometry of the woofer should conform to the limited available space and layout in general. In many cases, the passengers feel that the low-frequency contents are not satisfactory although the speaker specification covers the low frequencies. In this work, a thin panel is installed between the roof liner and the roof panel, and it is used as the woofer. The vibration field is controlled by many small actuators to create the speaker and baffle zones to avoid the sound distortion due to the modal interaction. The generation of speaker and baffle zones follows the inverse vibro-acoustic rendering technique. In the actual implementation, a thin acrylic plate of 0.53x0.2 m2 is used as the radiator panel, and the control actuator array is composed of 16 moving-coil actuators.

Environmental and fuel economy regulations (Eu 6d and WLTP RDE) on automobiles have been tightened recently. To counter this regulation, the global automobile industry is focusing on weight reduction, fuel efficient turbo charger, cooled EGR, thermal management, low friction and so on. However, the high-speed turbocharger makes turbulence, and resulting in airflow noise. This noise is transmitted indoor through the air intake system, which adversely affects the vehicle's competitiveness. Therefore, for turbo engine, it is essential to reduce the noise of the air intake system. The air intake system consists of air cleaner, air filter, air intake hose and air duct. The air flow noise of turbo-engine is mainly the emission noise emitted from the walls of air intake system. And the transfer path of turbo noise is in order of air intake hose, air cleaner and air duct. Therefore, it is effective to reduce the noise of the air intake hose located at the beginning of noise transfer path.

A signal lamp performs a function to inform the position and behavior of the vehicle. And it represents a specific design identity of the vehicle or brand identity. Recently it implements the unique three-dimensional effect while using a LED. However, a number of LEDs and complex form of the lens shape have to be applied, so results in the size, weight, cost increase. In this study, the hologram technology that is an exemplary technique for implementing the described three-dimensional image is applied. With a hologram, it is possible to reproduce a complex shape three-dimensional image by using a hologram film. Therefore the number of parts can be reduced. And it is possible to copy the film has a mass production benefits.

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.

In case of cooling module rotated by belt, many sources (vehicle’s vibration, belt’s tension and thrust force by rotated fan) are acting on it. Because it is not easy to analyze them individually, there were no rig test modes for pre-validation while developing a new vehicle. In this study, we correlated the strain gauges signal to belt’s tension and fan’s thrust force, and measured acceleration of a vehicle and cooling module by driving a vehicle on the several test roads. In that case of measured acceleration data, we could analyze it by using PDF and construct the representative rig test modes considering vibrational fatigue characteristics by using the FDS. These modes can be utilized while developing a new vehicle without measuring anymore. Also, we could understand each load’s characteristics. It is confirmed that the factors affecting the fatigue were not only the vehicle’s vibration but also the belt’s installation tension.

This paper presents the direct liquid-cooled power module with the circular pin fin which is the inverter parallel cooling system for high output EV/FCEV. The direct cooling system of a conventional inverter is designed to supply coolant along the direction in which the heating element such as Si-chip is disposed and discharge coolant to the opposite side. In case of the inverter, the higher the output is, the larger temperature difference between inlet and outlet becomes due to the heat exchange of the heat generation element, so that temperature difference depends on the position of Si-chip. Since lifetime is judged on the basis of maximum temperature of Si-chip, the inverter itself must be replaced or discarded due to durability of the inverter even though Si-chip can drive further. The simple way to solve this problem is to increase cooling flow rate, but this leads to excessive increase in pressure loss due to circular pin fin.

Impact resistance of plastic underbody parts was studied using simulated injection-molded specimen which can be tested according to different types of material used, injection molding variants like position and number of injection molding gates, and features of ribs. Material applied was glass fiber reinforced polyamide which can be used in underbody parts. Test was performed using several combinations of injection molding gates and rib types. From the test result, optimal design guide for plastic underbody parts was determined. Also, new high impact resistant plastic material made of glass fiber reinforced polyamide 66 (PA66) and polyamide 6 (PA6) alloy was developed and the material properties useful for CAE were determined. As a case study, oil pan and muffler housing were designed following the optimal design guide and CAE. And the reliability of the sample muffler housing designed was verified.

This study has been conducted to analyze microbial diversity and its community by using a method of NGS(Next generation sequencing) technique that is not rely on cultivation for microbial community in an core evaporator causing odor of car air conditioner. The NGS without any cultivation method of cultivation, has been developed recently and widely. This method is able to research a microorganism that has not been cultivated. Differently with others, it can get a result that is closer to fact, also can acquire more base sequence with larger volume in relatively shorter time. According to bacteria population analysis of 23 samples, It can be known limited number of bacteria can inhabit in Evaporator core, due to small exposure between bacteria and evaporate, as well as its environmental characteristics. With the population analysis, only certain group of it is forming biofilm in proportion.

In order to reduce the cost and weight of the soft-foamed instrument-panel (IP), we developed the new IP which is made by the 2 kinds of injection methods. One is the compression-injection with back-foamed foil inserted, and the other is two-shot injection with the passenger-side airbag (PAB) door. We named it ‘IMX-IP’ which means that all components (‘X’) of the IP with different resins are made In a Mold. The development procedure of this technology was introduced (1) Design of the new injection mold through TRIZ application, (2) Optimization of the injection conditions and back foamed-foil for minimizing the foam loss and thickness deviation, (3) Development of CAE method for two-shot injection compression, (4) Reliability performance test and application to the mass production. The reduction of the processes through the two-shot molding with back foamed-foil inserted made it possible to enhance soft feeling on IP and reduce the cost and weight simultaneously.

The focus of this paper is to develop an innovative vehicle layout and optimize vehicle body structure with the latest lightweight steel technologies, such as hydro-forming and hot stamping. Our BIW structure achieved a mass savings of 28 kg (−10%) compared to the mass of baseline BIW structure. (Base BIW : MD_Elantra)

A fractional recirculation of cabin air was proposed and studied to improve cabin air quality by reducing cabin particle concentrations. Vehicle tests were run with differing number of passengers (1, 2, 3, and 4), four fan speed settings and at 20, 40, and 70 mph. A manual control was installed for the recirculation flap door so different ratios of fresh air to recirculated air could be used. Full recirculation is the most efficient setting in terms of thermal management and particle concentration reduction, but this causes elevated CO₂ levels in the cabin. The study demonstrated cabin CO₂ concentrations could be controlled below a target level of 2000 ppm at various driving conditions and fan speeds with more than 85% of recirculation. The proposed fractional air recirculation method is a simple yet innovative way of improving cabin air quality. Some energy saving is also expected, especially with the air conditioning system.

Systematic numerical simulations were performed for the improvement of fuel efficiency and thermal performance of a compact size passenger vehicle. Both aerodynamic and thermal aspects were considered concurrently. For the sake of systematic evaluation, our study was conducted employing various design changes in multiple steps: 1) analysis of the baseline design; 2) elimination of the engine room components; 3) modification of the engine room component layout; 4) modification of the aerodynamic components (such as under body cover and cooling ducts). The vehicle performance characteristics corresponding to different design options were analyzed in terms of aerodynamic coefficient, engine coolant temperature, and surface temperatures of thermally critical components such as battery and exhaust manifold. Finally optimal design modification solutions for better vehicle performance were proposed.

The reduction of intake noise is a very important factor in controlling the interior noise levels of vehicles, particularly at low and major engine operating speeds. A vehicle intake system generally consists of air cleaner box, hose, duct, and filter element. Also, resonators and porous duct are included, being used to reduce intake noise. For more accurate estimation of the transmission loss (TL), it seems important to develop a CAE model that accurately describes this system. In this paper, simple methods, which can consider the effects of filter element and vibro-acoustic coupling, are suggested which could remarkably improve estimation accuracy of the TL. The filter element is assumed as equivalent semi-rigid porous materials characterized by the flow resistivity defined by the pressure drop, velocity, and thickness.