Search Results

A voxel model, which consists of minute cubic cells called voxels to express the shape of an object, can now be generated automatically from CAD data. Moreover, advances in high-speed computational techniques have made it possible to perform a structural analysis using such a voxel model. This paper presents some high-speed computational techniques to realize the analysis in practice and a method to treat a contact condition on the jagged surface that characterizes a voxel model to further expand the scope of application.

A flow analysis method with quick turnaround time has been studied for application to flows in the engine compartment of vehicles. In this research, a rapid modeling method based on the Cartesian mesh system was developed to obtain flow field information quickly. With this modeling method, the original shape is approximated by many small cubic cells, allowing automatic mesh generation in significantly less time. Moreover, a hierarchical mesh system that reduces the total number of meshes has been introduced. This multi-level mesh system is also highly capable of representing shapes in detail. Another important issue in flow calculations in the engine bay is the treatment of the boundary conditions such as the radiator and cooling fan. With the proposed method, the fluid dynamics characteristics of such components are measured, and characteristics such as the pressure loss/gain and the rotational vector of the fan are reflected in the flow field as empirical models.

The use of higher output engines and more auxiliary units is resulting in greater heat generation in the engine compartment. At the same time, design trends and demands for improved aerodynamic performance are diminishing the cooling air flow rate. These two sets of factors are making the thermal environment in the engine compartment more severe. In this work, heat flow in the engine compartment was investigated by numerical analysis and flow visualization, and flow control devices were devised for optimizing the temperature distribution. This paper discusses the heat flow optimization techniques and presents the results obtained in experiments with an actual vehicle.

The higher output levels attained by recent automotive engines have been accompanied with an increase in the amount of heat generated by the engine. This higher heat release level, together with the styling trend toward a lower hood line, requires a method for accurately predicting heat release to the engine coolant. In this research, the heat flow path in the engine was separated into several components and equations were formulated for estimating the amount of heat released by each component. The whole heat release to the engine coolant was obtained by totaling the heat release of each component.

The engine cooling system is required to provide much higher performance today owing to the improved power output of engines and the trend toward a more compact engine compartment. For front engine/rear drive vehicles equipped with a fluid coupling drive fan, one of the main problems that must be dealt with is the rise in coolant temperature during idling. This paper presents a new method to simulate the engine coolant temperature under idling condition, and an improved engine cooling system that features a totally redesigned fan blade for maximum efficiency. This new system, consisting of a high performance cooling fan shroud and coupling, achieves a substantial noise reduction and contributes to fuel economy and power output improvements.