• Design & Manufacturing
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• v.18 no.1
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• pp.39-45
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• 2024

The radiator grille has several air intakes. These holes cause the resin flows to divide and merge. As a result, weld lines occur. These weld lines and other problems appear in various forms depending on the grille pattern. To solve these problems, designers use injection molding analysis to proactively identify problems and determine optimal molding conditions. In this study, we conducted research on the effect and optimization of gates on injection molding of automobile radiator grille. The gates used in molding analysis are the side gate and the grape gate. We then compared the effects of each gate on weld line, injection pressure, clamping force, and deflection. As a result of the analysis applying the side gate, weld lines occurred in all major grilles. In contrast, in applying the grape gate, small weld lines occurred in the minor grille, but the weld line in the major grille could be prevented. The maximum injection pressure was reduced by 48.2% in applying the grape gate compared to applying the side gate. Additionally, the maximum clamping force was also reduced by 17.6%. To compare the amount of deformation, deflection values were measured at 20 identical locations. As a result, applying the grape gate showed a deformation improvement of at least 5.2% and up to 77.9%.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.659-666
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• 2007

In the present study, a numerical analysis of the three-dimensional heat transfer and fluid flow for a vehicle cooling system was developed. The flow field of the engine room between the grille and radiator was analyzed. The results show that, as the airflow inlet grille angle $\alpha$ is varied from $15^{\circ}$ to $-15^{\circ}$, the air flow rate compared with $\alpha=0^{\circ}$(horizontal) changes from -11.9% to +5.1%; while the heat flux from the radiator changes from -9.2% to +4.4%. When the airflow inlet bumper angle $\beta$ is varied from $-5^{\circ}$ to $+15^{\circ}$, the heat flux from the radiator compared with $\beta=0^{\circ}$(horizontal) increases up to +4.4%. When the airflow inlet grille angle $\alpha=-15^{\circ}$ and the bumper grill angle $\beta=+15^{\circ}$, the airflow rates and heat flux compared with($\alpha=0^{\circ}$, $\beta=0^{\circ}$) can be increased to +9.5% and +7.5%, respectively. The results indicate that the optimal angles for cooling efficiency are used.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.74-87
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• 2015

A numerical parametric study has been accomplished to figure out the effect of grille shape built in a small passenger car on the aerodynamic performance such as drag and mass flow rate through CRFM(Condenser Radiator Fan Module). Three grille opening parameters and three grille mesh parameters are selected and adopted to a simple shape passenger car model. This research will provide a design guideline for grille opening geometry and mesh shape in the grille. FLUENT, which is very well known commercial code, hires k-${\epsilon}$ turbulence model at the driving speed of 110km/h with moving wall boundary condition. A porous media condition is prepared to estimate the pressure drop amount through CRFM parts.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.10-15
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• 2005

This study was initiated to evaluate the cooling performance of CAC (charged air cooler) and radiator in the engine room of a mini bus. So we had firstly to predict the mass flow rate coming from radiator grille and front bum per opening using computational fluid dynamics (CFD) simulation based on 3D configuration. And simulations were carried out for different cooling module layout and bum per opening hole size on sam e vehicle operating condition. Simulation results show that CAC cooling performance at reverse protecting plate-applying model was much efficient than that of the bum per opening hole size-increasing model in IMTD point of view. Part of the CFD simulation results was com pared to with experimental data. It was confirm ed that the CFD approach using STAR-CD based on pursuing no-com promise solution could provide design engineers with useful design information in the early design stage of vehicle development.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.118-123
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• 1999

The recycle of the polycarbonate(PC)/acrylonitrile-butadiene-styrene(ABS) separated from the instrument panel (In-Panel) of the automotive was investigated. The small amount of polyurethane(PU) foam contained in the separated PC/ABS decreased the mechanical properties of the recycled PC/ABS. However, it is found that the PU foam formed the dispered phase of small particles at high temperature ($260^{\circ}C$) under high shear of the twin extruder, whereas it formed the big particles at low extrusion temperature ($220^{\circ}C$). The mechanical properties of the recycled PC/ABS extruded at high temperature was better than those at low temperature, which enabled the recycled PC/ABS seperated from In-Panel to be applied to the radiator grille without the addition of the compatibilizers or virgin PC/ABS. This was ascribed to the smaller particle sizes of the PU foam formed at high extrusion temperature under high shear.