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Engine starting vibration of hybrid vehicle with Toyota hybrid system has variations even in the same vehicle, and a large vibration that occurs rarely may cause stress to the passengers. The contribution analysis based on the vibration theory and statistical analysis has been done, but the primary factor of the rare large vibration has not been clarified because the number of factors is enormous. From this background, we apply machine learning that can reproduce multivariate and complicated relationships to analysis of variation factors of engine starting vibration. Variations in magnitude of the exciting force such as motor torque for starting the engine and in-cylinder pressure of the engine and timing of these forces are considered as factors of the variations. In addition, there are also nonlinear factors such as backlash of gears as a factor of variations.

The recent growth of available computational resources has enabled the automotive industry to utilize unsteady Computational Fluid Dynamics (CFD) for their product development on a regular basis. Over the past years, it has been confirmed that unsteady CFD can accurately simulate the transient flow field around complex geometries. Concerning the aerodynamic properties of road vehicles, the detailed analysis of the transient flow field can help to improve the driving stability. Until now, however, there haven’t been many investigations that successfully identified a specific transient phenomenon from a simulated flow field corresponding to driving stability. This is because the unsteady flow field around a vehicle consists of various time and length scales and is therefore too complex to be analyzed with the same strategies as for steady state results.

This paper describes the development of an innovative AWD system called Dynamic Torque Vectoring AWD for all-wheel drive (AWD) vehicles based on a front-wheel drive configuration. The Dynamic Torque Vectoring AWD system helps to achieve high levels of both dynamic performance and fuel efficiency. Significant fuel economy savings are achieved by using a new compact disconnection mechanism at the transfer and rear units, which prevents any unnecessary rotation of the propeller shaft. In addition, the system is also capable of independently distributing torque to the rear wheels by utilizing electronically controlled couplings on the left and right sides of the rear differential. This greatly enhances both on-road cornering performance and off-road driving performance.

A new method to measure in-cylinder flame propagation and mixture distribution has been developed. The distribution is derived from analyzing the temporal history of flame spectra of CH* and C2*, which are detected by a spark plug type sensor with multi-optical fibers. The validity of this method was confirmed by verifying that the measurement results corresponded with the results of high speed flame visualization and laser induced fluorescence (LIF) measurement. This method was also applied to analysis of cyclic combustion fluctuation on start-up in a direct injection spark ignition (DISI) engine, and its applicability was confirmed.

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 structure of HCCI (homogeneous charge compression ignition) combustion flames was quantitatively analyzed by measuring the two-dimensional gas temperature distribution using phosphor thermometry. It was found from the relation between a turbulent Reynolds number and Karlovitz number that, when compared with the flame propagation in an S.I. engine, HCCI combustion has a wider flame structure with respect to the turbulence scale. As a result of our experimentation for the influence of low temperature reaction (LTR) using two types of fuel, it was also confirmed that different types of fuel produce different histories of flame kernel structure.

Toyota Hybrid System (THS), that combines a gasoline engine and an electric motor was installed in the Prius, which was introduced in 1997 as the world's first mass-produced hybrid passenger car, and was vastly improved in 2003. The new Prius gained a status of highly innovative and practical vehicle. In 2005, combined with a V6 engine, THS had a further evolution as a Hybrid System for SUV, which was installed in the RX400h and Highlander Hybrid to be introduced into the world. This report will explain “new THS” which achieved both V8 engine power performance and compact class fuel economy, while securing the most stringent emission standard, SULEV.

Reducing disk brake squeal, especially low frequency disk brake squeal (1-5kHz), is an important technical issue in vehicles. The disk brake squeal mechanism has been shown in many papers (1), (2), (3), (4), (5), (6), (7), (8) and (9). Recently, the disk brake squeal comes to be simulated by Finite Element Analysis (FEA) for disk brake design (10), (11), (12), (13), (14), (15), (16), (17), (18) and (19). Though FEA is useful, it is sometimes difficult to modify in large when the prototype of disk brake system has been designed. First Order Analysis gives design concepts, which should be done before FEA. This paper shows First Order Analysis of low frequency disk brake squeal. The equation of motion is shown in 4 degrees of freedom model. In this equation the generalized force matrix is composed of the variations of pressure and friction force between each brake pad and brake disk. The generalized force matrix is arranged with a symmetric matrix and an anti-symmetric matrix.

The transfer efficiency for painting processes utilizing water-borne materials is low, and the residual paint is disposed of as waste. In this study, we focused on a recycling system to collect and dissolve the paint over-spray in the booth water, and to concentrate and regenerate it by means of an ultra filter (UF). Paint adaptable to the recycling system has been developed by providing compatibility between the high hydrophilicity of liquid paint and the high hydrophobicity of the paint film, in order to ensure the recyclability and the high anti-corrosion performance required of paint on automobile underbody parts. This recycling technology is used in an actual propeller shaft painting process and provides large waste reduction and a decrease in painting cost.

In the field of automotive gasoline engines, new products aiming at greater fuel economy and cleaner exhaust gases are under development with the aim of preventing environmental destruction. Severe ignition environments such as lean combustion, stronger charge motion, and large quantities of EGR require ever greater combustion stability. In an effort to meet these requirements, an iridium plug has been developed that achieves high ignitability and long service life through reduction of its diameter, using a highly wear-resistant iridium alloy as the center electrode.(1)(2) Recently, direct injection engines have attracted attention. In stratified combustion, a feature of the direct injection engine, the introduction of rich air-fuel mixtures in the vicinity of the plug ignition region tends to cause carbon fouling. This necessitates plug carbon fouling resistance.

A method of fatigue life estimation for the spot-welds of vehicle body structures by means of Finite Element Analysis (FEA) was studied. 6 general forces applied to a nugget of spot-weld under multiaxial loads were determined and the Nominal Structural Stress (σns) was calculated from them. It was confirmed that fatigue strength of the spot-welds under various multiaxial loads could be estimated universally by using σns. Based on the theory of elasticity of plates, stress of spot-weld nugget was analyzed. The theoretical equations for determining the principal stress at the nugget edge from6 general forces acting on a nugget were derived. And the principal stress was defined as the σns. The value of σns was determined by FEM that used a solid model and compared with the theoretical calculation value. They agreed quite well. Fatigue tests of DC specimens under various multiaxial loads (shear plus cross tension and tensile shear plus torsion) were conducted.

TOYOTA has designed a new family of automatic transaxles named the “Super ECT”. These are the next generation of automatic transaxles (AT), for FWD passenger cars. The aim of this development was compactness, lightness, and improvements in fuel economy and shift quality. There are several kinds of transaxles included in this group to match each of the FWD passenger cars and engines. The “U340E,” a four-speed automatic transaxle, has been developed as one member of this family. This is one of the most compact and light AT in its class, and has greatly contributed to the fuel economy of vehicles. This paper will give an overview of the “Super ECT” and the major features and performance of the U340E.

In a stage of designing a CVJ boot, analytic conditions of FEA method are established so that values calculated with the FEA method coincide with the actually measured values. This has made it possible to predict the life of the boot under bench testing. Furthermore, the boot field life can also be predicted by the minor rule based on the joint-angle frequencies of a vehicle. As a result, it has become possible to determine an optimal configuration in the design stage and to decrease the number of test cycles, resulting in reduced development lead time.

One of the main types of window regulators that are in current use is the X-arm type window regulator, which utilizes a linkage mechanism to raise and lower the window glass. One of the evaluation items that are necessary in analyzing the performance of a window regulator is the operating force that is required to operate the handle for moving up the window glass. It is difficult to estimate this force during the design stage. We have to take into consideration factors such as the influences of the various types of contacts and the elastic deformation of linkage arm. Therefore, we used the LS-DYNA, which is dynamic and kinematic nonlinear finite element analysis code, to develop a technique for analyzing the handle operating force. Then, we used this technique to conduct parameter studies to identify the factors that are believed to exert a greater influence on the operating force.

A practical shape optimization technique is presented. We employed the basis vector method to parameterize the shape of the structural domain that is usually discretized by the finite element method. VMA/GENESIS software, the optimization system with finite element analysis, sensitivity analysis, and numerical optimization capabilities, was used for this study. Various design problems such as body, chassis, and engine parts design are solved to demonstrate the effectiveness and the robustness of the present approach for automotive applications.

An experimental simulation method has been developed for predicting the noise and vibration characteristics of a complete vehicle when body frame stiffness is changed. This method was developed by means of an improved transfer function synthesis method. Advantages over numerical simulation methods, such as finite element analysis include dramatic reductions in computation time. This experimental method is also very easy to carry out with a few measurement data. By applying this method to investigate the effects of stiffness changes of different vehicle components on low frequency road noise, effective ways of reducing road noise were proposed in the first stage of vehicle development.

Sintered silicon nitride, particularly in structural ceramics, has superior properties such as low weight, heat resistance, wear resistance, etc. It is already being applied to automobile engine parts such as the swirl chamber and the turbine rotor. In recent years, the strength of silicon nitride has shown to be above 1000MPa. This has been achieved through advances in manufacturing technology such as materials powder, forming, sintering and so on. But the silicon nitride is easily damaged during grinding because it has less fracture toughness than metal. Consequently, the inherent strength of the material is not demonstrated in the actual products presently produced. It is assumed that the main cause of strength reduction is microcrack. In ordinary grinding methods, the length of microcrack has been estimated at approximately twenty micrometers by fracture mechanics analysis.

Toyota Motor Corporation has mass-produced turbochager with sillicon nitride ceramic rotors. A moment of inertia was reduced by 60% using ceramic rotor which improved turbochager response. The ceramic rotor was joined to metal shaft by new method which compensated problems in both shrink fitting and active brazing methods. They are generals for mechanical and chemical techniques, respectively. There still exist the following disadvantages. It is quite severe to controll the clearance of shrink fitting to obtain the reliability of the joint. The shaft may be loosened at high temperature with a small shrink-fit interference. The large shrink-fit interference could result in a failure of ceramic shaft due to large stress. Those may require a machinig accuracy with micron meter order of surface roughness which, leads to high cost.

In order to achieve higher assembly accuracy for automotive body, increased body rigidity, and decreased stamping and assembly costs in car body manufacturing, a new method of sheet metal stamping has been developed, in which several blanks of different strength and thickness are integrated using CO2 laser-welding. The stamping formability of the laser-welded blank is limited compared with that of the conventional single blank. It is very difficult to predict the exact decrease in formability for different positions of the weld line and for different matching of materials. Because experimental estimations were indispensable for stamping die designers to evaluate formability at the stage of planning dies, many man-hours were spent conducting actual experiments.

The muffler layout in the exhaust system has been optimized for the attenuation of exhaust noise which has not been studied much to this date. As a result, “Exhaust Manifold Muffler” has been developed. This unit is capable of efficiently muffling the primary and secondary componemts of the engine explosion stroke noise. Such task is achieved without deterioration of engine performance by allocating the volume at the junction of the exhaust manifold branch pipes. Acoustic characteristics of “Exhaust Manifold Muffler” have been analyzed by FEM and experimental methods, which have shown that not only does the volume placed at the junction of the exhaust manifold branch pipes work as a conventional muffler, but also prevents the exhaust manifold branch pipes from amplifying exhaust noise. This is the reason why “Exhaust Manifold Muffler” can muffle more efficiently than the conventional muffler.