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Automobiles will have to be applied strict regulations such as Euro7 against PM, HC, CO. The generation of these components are related to fuel deposition to the wall surface of the combustion chamber. Therefore, the fuel injection model of engine combustion CFD requires accurate prediction about the deposition and vaporization of fuel on the combustion chamber. In this study, multiphase flow numerical analysis that simulates fuel behavior on the wall surface was conducted first. Then, two model formulae about the contact area and the heat flux of a liquid film was constructed based on the result of multiphase flow numerical analysis method. Finally, the new film heat transfer model was constructed from these model formulae. In addition, it was confirmed that new heat transfer model can predict the liquid film temperature obtained by multiphase flow numerical analysis method accurately.

As a technology to reduce the heat loss of engines, heat insulation coating to the surface of combustion chamber has been received a lot of attention. In order to maximize the thermal efficiency improvements by the technology, it is important to clarify the location where heat insulation coating can reduce heat loss more effectively, considering the impact on abnormal combustion etc. In this study, transient behavior of wall heat flux distribution on the piston was analyzed using 3D Computational Fluid Dynamics (CFD) for three combustion modes (spark ignition combustion (SI), homogenous charge compression Ignition (HCCI) and spark controlled compression ignition (SPCCI)).

It was important for predicting wall heat flux to apply wall heat transfer model by taking into account of the behavior of turbulent kinetic energy and density change in wall boundary layer. Although energy equation base wall heat transfer model satisfied above requirements, local physical amounts such as turbulent kinetic energy in near wall region should be applied. In this study, in order to predict wall heat transfer by zero dimensional analysis, how to express wall heat transfer by using mean physical amounts in engine combustion chamber was considered by experimental and numerical approaches.

When the strain is temporarily stopped during tensile testing of a metal, a stress relaxation phenomenon is known to occur whereby the stress diminishes with the passage of time. This phenomenon has been explained as the change of elastic strain into plastic strain. A technique was devised for deliberately causing strain dispersion to occur by applying the stress relaxation phenomenon during stamping. A new step motion that pause the die during forming was devised; it succeeded in modifying the deep-draw forming limit by a maximum of 40%. This new technique was verified through tensile and actual stamping tests. It was confirmed that the use of step motion causes the strain to disperse, thereby modifying the deep draw forming limit. The degree to which the forming limit is modified is dependent on the stop time and the temperature. Step motion technology increases the stampability of high-strength, forming-resistant materials and allows for expanded application of these materials.

This paper describes a new approach and specific design procedure for more lightweight automotive Body in White (BIW) design. For a BIW structure with a target value for static stiffness, joints with high stiffness sensitivity are selected and a lightweight BIW joint design chart is produced from calculations combining topology optimization and thickness optimization. Using this chart made it possible to theoretically assign an optimum spring value to the BIW structure for the purpose of lightweight design, enabling substantial weight reduction in the base model while maintaining the same stiffness performance.

Improvement of indicated thermal efficiency of internal combustion engines is required, and increasing the compression ratio is an effective solution. In this study, using a CAE analysis coupling a 0-dimensional combustion analysis and a 1-dimensional heat conduction analysis, the influence of compression ratio on indicated thermal efficiency and combustion was investigated. As a result, it was found that there was an optimal compression ratio that gave the best indicated thermal efficiency, because the increase of cooling loss caused by high compression was bigger than the increase of theoretical indicated thermal efficiency in some cases. Next, the influence of cooling loss reduction on the optimal compression ratio was investigated. It was found that indicated thermal efficiency improved by reducing cooling loss, because the compression ratio which made the best indicated thermal efficiency was shifted to higher compression ratio.

Concept of the spray guided direct Injection spark ignition (DISI) was studied to improve the performance of wall-guided DISI. Focusing the effect of multi-hole injector location either centrally-mounted or side-mounted, mixture distribution and ignitability was studied. Computational Fluid Dynamics (CFD) modeling was applied to investigate the history of mixture, ignitable mixture existence around the spark plug in light load condition and homogeneity in full load condition. CFD results showed that side-mounted injection has an advantage over centrally-mounted injection in terms of mixture stability around the spark plug, although the slight disadvantage in homogeneity in full load condition. Side-mounted injection was selected because of robust ignitability potential and further experimental investigation was conducted. Stable combustion window against injection and ignition timing was investigated in experimentally.

Door beams are attached inside car doors as one way to protect passengers from shock when the car is side impacted. Though door beams made of high tensile strength steel predominate now, the use of aluminum is growing rapidly to reduce weight. The effects of cross-section and types alloy on the performance of aluminum extrusions as door beams were investigated. As the result, aluminum door beams were developed which have bending proper2ties comparing favorably with those of door beams made of high tensile strength steel with a tensile strength of 1470 N/mm2. Since the shape of the cross-section of aluminum extrusions is versatile, non-symmetric cross-sections composed of regions with different wall thicknesses and lengths can be produced. On the basis of this technology, a technology to design door beams with required bending properties for any car model was developed. This technology is already been utilized in various automobiles.

The effect of cross-section and type of alloy on the performance of aluminum extrusions as door beams was investigated. As a result, aluminum door beams were developed which have bending properties comparing favorably with those of door beams made of high tensile strength steel with a tensile strength of 1470 N/mm2. Furthermore, a technology to design door beams with the required performance and bending properties dealing with various car models was developed by making the most of the versatility of aluminum extrusions produced in various types of cross-sections.