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This paper proposes a novel method of verifying comprehensive driver model used for the evaluation of driving safety systems, which is achieved by coupling the traffic simulation and the driving simulator (DS). The method consists of three-step procedure. In the first step, an actual driver operates a DS vehicle in the traffic flow controlled by the traffic simulation. Then in the next step, the actual driver is replaced by a driver model and the surrounding vehicle maneuvers are replayed using the recorded data from the first step. Then, the maneuver by the driver model is compared directly with the actual driver's maneuver along the simulation time steps.

Grip feeling is an important facet in vehicle dynamics evaluation from a driver satisfaction and enjoyment standpoint. To improve grip feeling, we analyzed the subjective comments from test driver's about grip feeling and an evaluated human sensitivity to lateral motion. As a result, we found that drivers evaluate transient grip feeling according to the magnitude of lateral jerk. Next, we analyzed what vehicle parameters affect lateral jerk by using theoretical equations. As a result, we found that cornering power is an important parameter, especially the cornering power of rear tires as they can be create larger lateral jerk than can front tires.

Diffuse axonal injury (DAI) is the most frequent type of closed head injury involved in vehicular accidents, and is characterized by structural and functional damage of nerve fibers in the white matter that may be caused by their overstretch. Because nerve fibers in the white matter have an undulated network-like structure embedded in the neuroglia and extracellular matrix, and are expected to be much stiffer than other components, the strain in the nerve fiber is not necessarily equal to that in the white matter. In this study, the authors have measured strain of the nerve fibers running in various directions in porcine brain tissue subjected to uniaxial stretch and compared them with global strain (tissue strain). The nerve fiber strain had a close correlation with their direction, and was smaller than surrounding global strain.

This paper presents a design method for continuous fiber composites in three-dimensional space with locally varying orientation distribution and their fabrication method. The design method is formulated based on topology optimization by augmented tensor field design variables. The fabrication method is based on Tailored Fiber Placement technology, whereby a CNC embroidery machine prepares the preform. The fiber path is generated from an optimized orientation distribution field. The preform is formed with vacuum-assisted resin transfer molding. The fabricated prototype weighs 120 g, a 70% weight reduction, achieving 3.5× mass-specific stiffness improvement.

A series calculation methodology from the injector nozzle internal flow to the in-cylinder fuel spray and mixture formation in a diesel engine was developed. The present method was applied to a valve covered orifice (VCO) nozzle with the recent common rail injector system. The nozzle internal flow calculation using an Eulerian three-fluid model and a cavitation model was performed. The needle valve movement during the injection period was taken into account in this calculation. Inside the nozzle hole, cavitation appears at the nozzle hole inlet edge, and the cavitation region separates into two regions due to a secondary flow in the cross section, and it is distributed to the nozzle exit. Unsteady change of the secondary flow caused by needle movement affects the cavitation distribution in the nozzle hole, and the spread angle of the velocity vector at the nozzle exit.

Dynamic wind-tunnel tests of a simplified passenger car model were conducted using a two-degree-of-freedom model shaker. Time-resolved aerodynamic loads were derived from a built-in six-component balance and other sensors while the model underwent sinusoidal heaving and pitching motions at frequencies up to 8 Hz. The experimental results showed that frequency-dependent gains and phase differences between the model height/angle and the aerodynamic loads are in close agreement with those predicted by large-eddy simulation (LES) using an arbitrary Lagrangian-Eulerian (ALE) method. Based on these findings, transient aerodynamic loads associated with lateral motions were also estimated by LES analysis. Based on the above results, a full-unsteady aerodynamic load model was then derived in the form of a linear transfer function. The force and moment fluctuations associated with the vertical and lateral motions are well described by the full-unsteady aerodynamic load model.

The aim of this research is to develop the diesel combustion simulation (UniDES: Universal Diesel Engine Simulator) that incorporates multiple-injection strategies and in-cylinder composition changes due to exhaust gas recirculation (EGR), and that is capable of high speed calculation. The model is based on a zero-dimensional (0D) cycle simulation, and represents a multiple-injection strategy using a multi-zone model and inhomogeneity using a probability density function (PDF) model. Therefore, the 0D cycle simulation also enables both high accuracy and high speed. This research considers application to actual development. To expand the applicability of the simulation, a model that accurately estimates nozzle sac pressure with various injection quantities and common rail pressures, a model that accounts for the effects of adjacent spray interaction, and a model that considers the NOx reduction phenomenon under high load conditions were added.

This paper presents typical flow structures around a 60%-scale wind-tunnel model of a Formula One (F1) car, using planar particle image velocimetry (PIV). The customized PIV system is permanently installed in a wind tunnel to help aerodynamicists in the development loop. The PIV results enhance the understanding of the mean velocity field in the two-dimensional plane in some important areas of the car, such as the front-wheel wake and the underfloor flow. These real phenomena obtained in the wind tunnel also help maintain the accuracy of simulations using computational fluid dynamics (CFD) by allowing regular checking of the correlation with the real-world counterpart. This paper first surveys recent literature on unique flow structures around the rotating exposed wheel, mostly that on the isolated wheel, and then gives the background to F1 aerodynamics in the late 2000s.

More than twenty years have passed since we invented polymer-clay nanocomposites (PCN), in which only a few wt.-% of silicate is randomly and homogeneously dispersed in the polymer matrix. When molded, these nanocomposites show superior properties compared to pristine polymers such as tensile strength, tensile modulus, heat distortion temperature, gas barrier property, and so on. The number of papers on PCN has increased rapidly in recent years, reaching over 500 only in 2005. As the pioneers of the new technology, we will review its history highlighting our works. Epoch-making events of PCN are as follows: In 1985, The first PCN, nylon 6-clay hybrid (NCH), was invented. In 1987, NCH was first presented at the ACS Fall Meetings. In 1989, NCH was presented at the MRS Fall Meetings, firing PCN. In 1989, Toyota launched cars equipped with a NCH part. In 1996, Clay was found to cause a memory effect in liquid crystals.

Estimating distant road structure will be an important factor in determining the extent of danger of detected obstacles. There are some methods to estimate the road structure by an image from an onboard camera. However, the results are not sufficient due to the vertical curvature of roads and the limitation of image resolution. In this paper, a new method is proposed to estimate the 3-D road structure by fusion of a 2-D digital road map and an image from a camera. The effect of this method is confirmed by using synthesized data and actual data.

Recently, there has been many practical applications of fuzzy control. Applications of fuzzy control to vehicles are more effective. However, they require more input and output channels as well as higher speed inference ability than typical applications require. We have developed a tool for developing a fuzzy control system available on a vehicle. The tool consists of a fuzzy inference board and a laptop personal computer with a color display executing a user interface software. The fuzzy inference board can be directly connected with an electronic control unit for vehicle control, and has 10 input channels, 5 output channels and 256 rules. The user interface software mainly provides two functions: 1) The screen editor for membership functions and rules. 2) The real-time monitor for input, output, and grade values when fuzzy inference is executed.

Temperature distributions on the surface of a connecting rod big end bearing were measured to understand the margin to the allowable limiting temperature. The results show that the temperature difference between the bearing surface and the feed oil is independent of the engine load but quadratically increased with the engine speed, and that the bearing surface temperature on the rod side is higher than those on the cap side, and that the high temperature regions appeared near the edges on the rod side of the bearing under high speed operations. The results were analyzed by the observation of rubbing traces on the bearing surface and the EHD lubrication theory.

The purpose of this study is to construct a method to predict vehicle cabin VOC (volatile organic compounds) concentration. Several methods have been used previously to evaluate VOC emission from interior parts and materials (e.g., sampling bag method, 1 m3 chamber method). However, measurement conditions vary depending on the method used, making it difficult to predict vehicle cabin VOC concentration from the VOC values evaluated for component parts. In this paper, we focused on measurement of toluene concentration using the bag method and investigated the relationship between VOC emissions and measurement conditions. We assumed that the amount of VOC contained in the parts (RA) and the adsorptive capacity of the parts (K) can describe the VOC amount obtained (RG) when the VOC concentration in the bag reaches equilibrium. We developed a novel method incorporating a labeled compound to predict RA and K.

The Japan Automobile Manufacturers Association (JAMA) has recommended the voluntary regulation of the levels of volatile organic compound (VOC) emissions from vehicles. However, initiatives to reduce these emissions further are being implemented in Japan to create a healthier and more comfortable environment within vehicles. In this study, it was attempted to estimate the observable amounts of VOC emitted from products used in vehicles based on the actual emission of VOC from the products components. The VOC we focused on was toluene. The amounts of toluene volatilizing from the components of a disassembled vehicular product were measured and tested whether a simple sum of these values could be used to predict the amount of toluene emitted from the whole product. However, it was found this predicted value deviated significantly from the actual amount of toluene emitted from the product.

In recent years, problems such as global warming, the depletion of natural resources, and air pollution caused by emissions are emerging on a global scale. These problems call for efforts directed toward the development of fuel-efficient engines and exhaust gas reduction measures. As a solution to these issues, performance improvements should be achieved on the oil that lubricates the sliding sections of engines. This report points to features required of future engine oil-such as contribution to fuel consumption, minimized adverse effects on the exhaust gas aftertreatment system, and improved reliability achieved by sludge reduction-and discusses the significance of these features. For engine oil to contribution of engine oil to lower fuel consumption, we examined the effects of reduced oil viscosity on friction using gasoline and diesel engines.

In the studies of disc brake squeal, the vibration modes on squealing were measured, and calculated [1, 2 and 3]. By those results to the disk rotor, it is clear that the specific type of the modes affect the squeal generation. It is not clear whether mounting bracket mode shapes contribute to squeal, because the mounting bracket mode shapes cannot be classified in the same way as the rotor mode shapes. In this paper, by using FEM modal analysis the vibration modes of the mounting bracket are classified systematically. And by adopting this classification to the vibration mode of mounting on squealing, it is confirmed that the specific type of modes of mounting affect the squeal generation.

Engine running tests and excitation tests were performed to reveal the vibration behavior in a turbocharger-exhaust system related to the turbocharger's operating sound. The operating sound was caused by the resonant vibration excited by the unbalanced inertia force of the rotor. The turbocharger-exhaust system had six resonant frequencies in the operating speed range of the rotor. At resonant speeds, the whole turbocharger was translating or rotating due to bending and torsional deflection of the exhaust manifold. Based on the test results, the vibration behavior could be well simulated by a rigid body-spring model with six degree of freedom. Furthermore, the model was used to analyze the relation between the stiffness of the exhaust manifold and the vibration level. Increasing the stiffness of the exhaust manifold was effective in sufficiently reducing the vibration and sound.

The finite element method (FEM) is effective for analyzing brake squeal phenomena. Although FEM analysis can be used to easily obtain squeal frequencies and complex vibration modes, it is difficult to identify how to modify brake structure design or contact conditions between components. Therefore, this study deals with a practical design method using sensitivity analysis to reduce brake squeal, which is capable of optimizing both the structure of components and contact conditions. A series of analysis processes that consist of modal reduction, complex eigenvalue analysis, sensitivity analysis and optimization analysis is shown and some application results are described using disk brake systems.

The stratification feature of DI gasoline combustion was studied by using a constant volume combustion vessel. An index of stratification degree, defined as volumetric burning velocity, has been proposed based on the thermodynamic analysis of the indicated pressure data. The burning feature analysis using this stratification degree and the fuel vapor concentration measurement using He-Ne laser ray absorption method were carried out for the swirl nozzle spray with 90° cone angle and the slit nozzle spray with 60° fan angle. Ambient pressure and ambient temperature were changed from atmospheric condition to 0.5∼0.6 MPa and 465 K, respectively. Air Swirl with swirl ratio of 0∼1.0 were added for the 90° swirl nozzle spray. Single component fuels with different volatility and self-ignitability from each other were used besides gasoline fuel. The major findings are as follows. High ambient temperature improves stratification degree due to the enhanced fuel vaporization and vapor diffusion.

In this paper, we will introduce a stereo vision system developed as a sensor for a vehicle's front monitor. This system consists of three parts; namely, a stereo camera that collects video images of the forward view of the vehicle, a stereo ECU that processes its output image, and a near-infrared floodlight for illuminating the front at night. We were able to develop an obstacle detection function for the Pre-Crash Safety System and also a traffic lane detection function for a Lane-Keeping Assist System. Especially in regard to the obstacle detection function, we were able to achieve real-time processing of the disparity image calculations that had formerly required long processing times by using two types of recently developed LSIs.