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To get a better understanding of the characteristics of the high pressure gasoline sprays impinging on a wall, a fundamental study was conducted in a high-temperature high-pressure constant volume vessel under the simulated engine conditions of in-cylinder pressures, temperatures, and wall temperatures. The injection pressure was varied from 20 to 120 MPa. The spray tip penetration, vapor mass distribution, and vaporization rate were quantitatively measured with the laser absorption-scattering (LAS) technique. The velocity fields of the wall-impinging sprays under vaporizing conditions were measured with the particle image velocimetry (PIV) technique using silicone oil droplets as tracers. The effects of injection pressure and spray/wall interactions on spray characteristics were investigated. The results showed that the increased injection pressure improved penetration, vaporization, and turbulence of the sprays.

On-road turbulences caused by sources such as atmospheric wind and other vehicles influence the flow field and increases the drag in a vehicle. In this study, we focused on a scenario involving a passing vehicle and investigated its effect on the physical mechanism of the drag increase in order to establish a technique for reducing this drag. Firstly, we conducted on-road measurements of two sedan-type vehicles passed by a truck. Their aerodynamic drag estimated from the base pressure measurements showed different increment when passed by the truck. This result raised the possibility of reducing the drag increase by a modification of the local geometry. Then, we conducted wind tunnel measurements of a simplified one-fifth scale vehicle model in quasi-steady state, in order to understand the flow mechanism of the drag increase systematically.

A road vehicle’s cornering motion is known to be a compound motion composed mainly of forward, sideslip and yaw motions. But little is known about the aerodynamics of cornering because little study has been conducted in this field. By clarifying and understanding a vehicle’s aerodynamic characteristics during cornering, a vehicle’s maneuvering stability during high-speed driving can be aerodynamically improved. Therefore, in this study, the aerodynamic characteristics of a vehicle’s cornering motion, i.e. the compound motion of forward, sideslip and yaw motions, were investigated. We also considered proposing an aerodynamics evaluation method for vehicles in dynamic maneuvering. Firstly, we decomposed cornering motion into yaw and sideslip motions. Then, we assumed that the aerodynamic side force and yaw moment of a cornering motion could be expressed by superposing linear expressions of yaw motion parameters and those of sideslip motion parameters, respectively.

A mixed time-scale subgrid large eddy simulation was used to simulate mixture formation, combustion and soot formation under the influence of turbulence during diesel engine combustion. To account for the effects of engine wall heat transfer on combustion, the KIVA code's standard wall model was replaced to accommodate more realistic boundary conditions. This were carried out by implementing the non-isothermal wall model of Angelberger et al. with modifications and incorporating the log law from Pope's method to account for the wall surface roughness. Soot and NOx emissions predicted with the new model are compared to experimental data acquired under various EGR conditions.

Combustion behavior in Rotary Engine (RE) is quite different from that in conventional reciprocating engines. Therefore, it is important to observe the combustion in RE. In the previous studies, an optical RE was developed, which enabled the observation of the flame propagation in the rotor rotating direction (side view). In the present study, modification was made to the optical RE so that the observation of the flame propagation in the rotor width direction (bottom view) became possible. By using two high-speed cameras, the combustion in RE was observed by bottom view and side view simultaneously. Consequently, it was found that the flame propagation in the rotor width direction is also important for better engine performance as well as that in the rotor rotating direction.

The present study investigated the aerodynamic pitching stability of sedan-type vehicles under the influence of A- and C-pillar geometrical configurations. The numerical method used for the investigation is based on the Large Eddy Simulation (LES) method. Whilst, the Arbitrary Lagrangian-Eulerian (ALE) method was employed to realize the prescribed pitching oscillation of vehicles during dynamic pitching and fluid flow coupled simulations. The trailing vortices that shed from the A-pillar and C-pillar edges produced the opposite tendencies on how they affect the aerodynamic pitching stability of vehicles. In particular, the vortex shed from the A-pillar edge tended to enhance the pitching oscillation of vehicle, while the vortex shed from the C-pillar edge tended to suppress it. Hence, the vehicle with rounded A-pillar and angular C-pillar exhibited a higher aerodynamic damping than the vehicle with the opposite A- and C-pillars configurations.

The purpose of this study is to define requirements for technological and business success in the world's first implementation of Reverse-Supply-Chain, in which bumper materials of end-of-life vehicles (ELV) are recycled for use as ingredients in new bumper materials. In Japan, ELVs are recovered following to the government regulation. About 20% (700,000 ton) of such collected ELVs are automotive shredder residues (ASR), most of which are burnt as fuel or used as landfill trash. ASRs are mainly plastics, which are largely used as materials of bumpers. The reverse-supply-chain was started as a small business by a collaboration between the car manufacture (Mazda), dismantler, and resource-recycling business operator, and enhanced by the development of easy-to-recycle bumpers, technologies of paint removal from crushed bumpers and sorting-out, a material quality control method, and improvement in transportation efficiency.

In the present study, numerical simulation coupling convection and radiation in vehicle was done to analyze the formation of the temperature field under the non-uniform thermal condition. The scaled cabin model of simplified compact car was used and the thermal condition was determined. The fore floor, the top side of the inst. panel, the front window and the ceiling were heat source. The lateral side walls were cooled by the outdoor air and the other surfaces were adiabatic. It is same with the experimental condition presented in Part 5. In order to analyze the individual influence of each heat source, Contribution Ratio of Indoor climate (CRI) index was used. CRI is defined as the ratio of the temperature rise at a point from one individual heat source to the temperature rise under the perfect mixing conditions for the same heat source.

In the present study, two kinds of simplified vehicle models, which can reproduce flow structures around the two sedan-type vehicles in the previous study, are constructed for the object and the unsteady flow structures are extracted using Large-Eddy Simulation technique. The numerical results are validated in a stationary condition by comparing the results with a wind-tunnel experiment and details of steady and unsteady flow characteristics around the models, especially above the trunk deck, are investigated. In quasi- and non- stationary manner with regard to vehicle pitch motion, unsteady flow characteristics are also investigated and their relations to an aerodynamic stability are discussed.

This study shows an example in which the conventional aerodynamic evaluation method that focuses on “steady” aerodynamic lift coefficient is not necessarily sufficient to evaluate vehicle's straight-ahead stability at high speed, and proposes a new aerodynamic evaluation method for vehicle stability. In vehicle development, it is generally said that vehicle with lower aerodynamic lift coefficient has better straight-ahead stability at high speed. However, in some cases, straight-ahead stability differs between two vehicles with similar low aerodynamic lift coefficient. It is natural to think that this variation is caused by the difference of suspension characteristics or vehicle body rigidity. But from our experiences, different straight-ahead stability was observed between two vehicles having same suspension characteristics, same vehicle body rigidity and almost similar aerodynamic lift coefficient, but different vehicle configurations.

Experiment and CFD have been performed to clarify the distribution of wind noise sources and its generation mechanism for a production vehicle. Three noise source identification techniques were applied to measure the wind noise sources from the outside and inside of vehicle. The relation between these noise sources and the interior noise was investigated by modifying the specification of underbody and front-pillar. In addition, CFD was preformed to predict the noise sources and clarify its generation mechanism. The noise sources obtained by simulation show good agreement with experiment in the region of side window and underbody.

The quest to simulate noise problems has led to the building of larger and more detailed finite element models in order to perform vibration solutions to higher frequencies. This leads to the building of solid finite element models of complex geometries, such as castings, which might previously have contained less detail or even been built with shell elements. Unfortunately, detailed geometric representations used to build models do not always agree with as built parts and lead to discrepancies between analysis results and test data. This paper presents an approach that reduces the time and cost necessary to identify these differences.

We have developed injection molding technologies consist of a new high-strength long-glass fiber reinforced polypropylene (PPLGF). They are key technologies of new modular design for substantial reductions of weight and cost, offering integrated functionality. The strength of injection molded parts are three times stronger than that of the conventional material. This technology makes it possible to replace parts from steel stamping and press molded glass-mat reinforced polypropylene. The front end and door modules of Atenza / Mazda6, Demio / Mazda2, RX-8 employs the module carriers using this material, resulting in dramatic weight and cost savings. (Fig. 1)

We have developed injection molding technologies consist of a new high-strength long-glass fiber reinforced polypropylene (PPLGF). They are key technologies of new modular design for substantial reductions of weight and cost, offering integrated functionality. The strength of injection molded parts are three times stronger than that of the conventional material. This technology makes it possible to replace parts from steel stamping and press molded glass-mat reinforced polypropylene. The front end and door modules of Mazda 6 employ the module carriers using this material, resulting in dramatic weight and cost savings.

Aerodynamic noise generated in production vehicle has been evaluated using experiment and numerical simulation. Finite difference method (FDM) and finite element method (FEM) are applied to analyze the flow field, and Lighthill's analogy is employed to conduct acoustic analysis. The flow fields around front-pillar obtained by numerical simulations agree with those by experiment for two cases with different front-pillar shape. Moreover, the distribution of acoustic source predicted by FEM is consistent with that obtained by experiment. Present study ascertained the feasibility and applicability of FEM with SGS model towards prediction of aerodynamic noise generated in production vehicle.

Thixomolding® produces net-shape parts from Magnesium alloys in a single step process involving high speed injection molding of semi-solid thixotropic alloys. A description of the process and status of commercial developments will be presented.. The mechanical properties and microstructures of Thixomolded® AZ-91D magnesium materials will be presented. Tensile strengths of semi-solid AZ-91D at both room temperature and elevated temperatures ( 373K, 423K) are compared with die cast AZ-91D. Data on enhanced creep properties of Thixomolded® AZ91-D alloy relative to die cast AZ-91D will be examined with respect to relative changes in microstructural features. Controlling the percent solids in the semi-solid state prior to injection molding can lead to improved creep performance for use in net-shape automotive components.