• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.55-58
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• 2008

Hydroforming is a forming technology in which a steel tube is set in a die and formed to fit a specified shape by applying hydraulic pressure from inside the tube while also applying force in the tube axial direction (axial feed). In present study, the entire design process chain for an automotive cross-member was simulated and developed using hydroforming technology on high-strength steel. The part design stage required a feasibility study. The process was designed using computer-aided design techniques to confirm the actual hydroformability of the part in detail. The possibility of using hydroformable cross-member parts was examined using cross-sectional analyses, which were essential to ensure the formability of the tube material for each forming step, including pre-bending and hydroforming. The die design stage included all the components of a prototyping tool. Press interference was investigated in terms of geometry and thinning.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.162-168
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• 2009

The real-time multibody vehicle model based on the subsystem synthesis method has been developed. Suspension, anti roll bar, steering, and tire subsystem models have been developed for vehicle dynamics. The compliance effect from bush element has been considered using a quasi-static method to achieve the real time requirement. To validate the developed vehicle model, a quarter car and a full vehicle simulations have been carried out comparing simulation results with those from the ADAMS vehicle model. Real time capability has been also validated by measuring CPU time of the simulation results.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.169-175
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• 2009

Real-time multibody vehicle dynamics software has been developed for virtual handling tests. The software can be utilized for HILS(Hardware In the Loop Simulations) and consists of three modules such as a graphical vehicle modeling preprocessor, a real time dynamics solver, and a virtual reality graphic postprocessor for virtual handling tests. In the graphical vehicle modeling preprocessor, vehicle hard point data for a suspension model are automatically converted into multibody vehicle model. In the real time dynamics solver, the efficient subsystem synthesis method is used to create multibody equations of motion for a subsystem by a subsystem. In the virtual reality graphic postprocessor, an animator has been also developed by using Matlab Virtual Reality Toolbox for virtual handling tests.

• 한국기계가공학회지
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• 제15권2호
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• pp.1-8
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• 2016

Generally, electrical circuits are fabricated as Printed Circuit Boards (PCBs) and mounted on the casing of the product. Additionally, this requires many other parts and some labor for assembly. Recently, molding technology has increasingly been applied to embed simple circuits in plastic casing. The technology is called a Molded Interconnected Device (MID). By using this technology, PCB fabrication can be replaced by molding, and much of the corresponding assembly process for PCBs can be eliminated if the circuit is simple enough for molding. Furthermore, as the improvement of conductive materials and printing technologies of simple electric circuits can be printed directly on the casing part, this also reduces the complexity of the product design and production cost. Therefore, this paper introduces a new MID fabrication process using direct 3D printing technology. Additionally, it is applied to an automotive part of a cruise control switch. The methodology and design are shown.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.140-143
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• 2003

The drawbead is an important part in sheet metal forming for automotive part and its effect is affected by various process parameters. Therefore in this study, drawbead friction test was performed at various process parameters - panels (cold rolled and galvanized sheet steel), lubricants (having three different viscosities), bead materials(steel, iron) and surface treatment of bead (Cr plating). Circular shape bead has been used for the test. The results show that friction and drawing characteristics were mainly influenced by the nature of zinc coating, viscosity of lubricants, surface treatment of a bead and hardness of coated layer.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.56-61
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• 2010

This paper presents dynamic clearance verification considering engine movement for vehicle engine room package and validates through physical vehicle test. Traditionally, static clearance guide has been used for engine room package, but it's only 2-dimension criteria that results in requiring unnecessary space and it's not possible to conduct engine movement with real driving conditions. Thus, the dynamic DMU considers engine movement based on 28 load cases that are Roll Data analyzed by CAE for maximum engine movement and visualizes part-to-part dynamic clearance into virtual space. The dynamic DMU enables to develop compact engine room package without unnecessary space. The result of comparison between simulation and physical test has 0.892 correlation coefficient.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.23-29
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• 2001

This paper is the second of companion papers, which investigate port-masking effects on emission and fuel economy. Port-masking was applied to commercial SOHC 3-valve engine by inserting masking plates between manifold and port. To induce various conditions of stratification, six types of masking plates were applied. In this paper, main interest is focused on the influence of injection timing on emission and fuel economy. Various injection timing was applied to the six cases, under the stoichiometric and lean-limit air-fuel ratio. Under the stoichiometric condition, an explanation about the reason of the change in emission level due to injection timing change is given. It is observed that NOx emission under the LML condition varies significantly when the injection timing changes.

• 한국자동차공학회논문집
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• 제4권5호
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• pp.187-196
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• 1996

In this study, 3-dimensional finite element model of a diesel engine cylinder head was made to accomplish heat transfer analysis and also thermal stress and deformation analysis. Heat release analysis and Nusselt-Reynolds correlations were applied to determine the convective boundary conditions which are required for heat transfer analysis to calculate temperature distribution. Thermal stress distribution was also investigated from heat transfer analysis results. Steady state temperature and heat flux were measured by using K-type thermocouples and then compared with numerical results to give a guarantee for the propriety of numerical analyses.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.90-105
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• 1996

A real tine simulator of running power train for a construction vehicle was developed. The simulator mainly consists of following two parts; (1) running power train part and (2) running load generation part. An optimal servo control algorithm was adopted for designing the multi-variable digital control system of the simulator. By experiments investigating response characteristics under step-wise variation or pre-determined scenario of target vehicle velocity and target load torque, it was verified that the simulator could reproduce physical situations at and actual vehicle with excellent similarity.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.9-17
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• 2001

This paper is the second of 3 companion papers which investigate axial stratification process. In-cylinder fuel behavior has been investigated in the port injected Sl engine by visualizing for the purpose of understanding stratification. Planar laser light sheet from an Nd:YAG laser has been illuminated through the transparent quartz cylinder of the single cylinder optical engine and the Mie scattered light has been captured through the quartz window in the piston head with an ICCD camera. Fuel has been replaced with an air-ethanol mixture to utilize atomized fuel spray fur the visualization purposes. This results have been compared with steady flow concentration measurement. For low/medium swirl port, the early injection makes such a fuel distribution state that is upper-rich, middle-lean and lower-rich along the combustion chamber and cylinder by tumbling motion. On the other hand, the late injection induces upper-rich, middle-lean and lower-rich state due to the short fuel penetration.