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This paper presents a vehicle dynamic simulation using a finite element method for performing more accurate simulations under extreme operating conditions with large tire deformation. A new hourglass control scheme implemented in an explicit finite element analysis code LS-DYNA(1) is used to stabilize tire deformation. The tires and suspension systems are fully modeled using finite elements and are connected to a rigid body that represents the whole vehicle body as well as the engine, drive train system and all other interior parts. This model is used to perform cornering and braking behavior simulations and the results are compared with experimental data. In the cornering behavior simulation, the calculated lateral acceleration and yaw rate at the vehicle's center of gravity agree well with the experimental results. Their nonlinear behavior is also well expressed.

The SKY Project (Start ITS from Kanagawa, Yokohama) was launched in October 2004 in Yokohama, Japan in order to contribute to the local community by reducing traffic accidents and congestion. SKY is a private sector collaboration between Nissan Motor Co., Ltd., NTT DoCoMo, Inc., Panasonic Corporation, and Xanavi Informatics Corporation (now Clarion Ltd.). Support has also been provided from the public sector, namely the National Police Agency of Japan (NPA) and the Kanagawa Prefectural Police. Through the use of in-vehicle technology and an Intelligent Transportation Systems (ITS) that communicates with the infrastructure, information on nearby vehicles and the surrounding traffic environment can be utilized to reduce traffic accidents, shorten travel times, and increase fuel savings. These are the goals of the SKY project. This paper shows the results of early stage testing and the introduction of newly started trials.

This paper describes the development of a vehicle with four-wheel steering in which the rear wheels can be controlled electronically in addition to the conventional front-wheel steering system. In the method for steering the rear wheels, the side-slip angle at the vehicle's center of gravity is maintained at zero, which improves the basic dynamic properties of the vehicle. This approach allows greater maneuverability at low speed by means of counter-phase rear steering and improved stability at high speed through same-phase rear steering. However, the use of counter-phase rear steering to improve maneuverability gives rise to problems in regard to practicality. In addition, continuously controlled four-wheel steering, using counter-phase at low speed and same-phase at high speed, leads to many other problems regarding practicality because of the strong apparent understeer characteristics.

Nissan has developed a second generation ceramic turbocharger rotor which provides greater reliability and higher performance than a conventional ceramic rotor. The new rotor is made of silicon nitride, which has demonstrated sufficient strength in vehicle applications. The bonding technique for joining the ceramic rotor to the metal shaft has been confirmed through experimentation to have sufficient reliability. The second generation rotor is featured by the low stress design and higher dynamic strength, and two factors contribute to its higher reliability. The rotor shape was optimized on the basis of results obtained in two analyses of particle impact resistance and applied combined stress. Test results show that the reliability of the second generation rotor have been substantially improved over those of the conventional rotor now being used on production vehicles.

Electric Vehicle distinctive techniques in order to enhance the vehicle dynamic performance have been studied and applied to Nissan LEAF. From the viewpoint of performance design parameters, this paper introduces the application items focusing on effectuality for the vehicle behavior by means of the yawing motion and the rolling motion control of its vehicle. As the result, the effects of vehicle performance are shown in experimental data.

The energy crisis and rising gas price in the 2000s led to a growing popularity of hybrid vehicles. Hyundai-Kia Motors has been challenging to develop the new efficient eco-technology since introducing the mild type compact hybrid electric vehicle for domestic fleet in 2004 to meet the needs of the increasing automotive-related environmental issues. Now Hyundai has recently debuted a full HEV for global market, Sonata Hybrid. This system is cost effective solution and developed with the main purpose of improving fuel consumption and providing fun to drive. Presenter Seok Joon Kim, Hyundai Motor Company

This paper reports about a trial for miniaturization of an air-cooled inverter integrated with motor, which is realized by reduction of the total volume of smoothing capacitor. An integrated system prototype was constructed with a disk-shaped inverter positioned at the rear end of the motor. We examined the possibility of using a ceramic capacitor, which features a higher heat-resistance temperature, lower internal resistance and higher capacity density than a film capacitor. At the same level of capacitance, the volume of a ceramic capacitor is less than one-half that of a film capacitor, enabling the size of the smoothing capacitor to be reduced to approximately one-fifth that of the currently used device. A suitable circuit configuration and physical layout of distributed smoothing capacitors and corresponding power device modules are proposed and demonstrated.

This paper presents the technologies incorporated in an electric vehicle (EV)/hybrid electric vehicle (HEV) inverter built with power semiconductors of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) instead of conventional silicon (Si) insulated gate bipolar transistors (IGBTs). A SiC inverter prototype of 2.9 L in size for driving an 80-kW motor was fabricated and evaluated on a motor test bench. The SiC inverter prototype attained average efficiency of 98.5% in the Worldwide harmonized Light-duty Test Cycle (WLTC) driving mode. The two main technologies achieved with this SiC inverter prototype are described. The first one is a new direct-cooled power module with a thick copper (Cu) heat spreader located under the semiconductors that improves thermal resistance by 34% compared with a conventional direct-cooled power module.

The durability test with road-load input is necessary for evaluating durability of body and chassis structure in automotive applications. This paper shows the method to analyze road-load input to a suspension system for development of a simple component level bench test. This method enables the extraction of the essential inputs to evaluate the durability of suspension parts using the transfer function (frequency response function) measured by Multi-axial Road Simulator and wheel force transducers. These extracted inputs contribute to development of a new realistic component bench test.

A new belt-drive continuously variable Transmission (B-CVT) was introduced into the Japanese market in September 1997 by Nissan Motor Co., Ltd. It transmits a maximum torque of 196 Nm and represents a major breakthrough of the torque limit transmitted by B-CVTs, thus opening a new epoch for the automatic transmission. The major features of the CVT are transmission of high torque between a steel belt and pulleys, electronic control of high hydraulic-pressure to pulleys and a torque converter with an electronically controlled lockup clutch engaging at low vehicle speeds. A CVT fluid formulated for this CVT was designed to optimize these features and this paper describes the performance of the CVT fluid in lab-scale tests and an endurance test of the CVT unit. In order to realize high torque transmission between a steel belt and pulleys, high friction between metal/metal contacts is required with normal wear.

The International Lubricant Standardization and Approval Committee (ILSAC) ATF subcommittee members have compared the two oxidation bench test methods, Aluminum Beaker Oxidation Test (ABOT) and Indiana Stirring Oxidation Stability Test (ISOT), using a number of factory-fill and service-fill ATFs obtained in Japan and in the US. In many cases, the ATFs were more severely oxidized after the ABOT procedure than after the same duration of the ISOT procedure. The relative severity of these two tests was influenced by the composition of the ATFs. The bench test oxidation data were compared with the transmission and the vehicle oxidation test data.

This paper describes the Nissan R01A model automatic transmission, focusing in particular on the basic design concept, control system and the various control techniques it incorporates. This 4-speed transmission, installed in Nissan's rear-wheel-drive vehicles, was designed from the ground up and significant construction and control mechanism improvements were made over the former conventional model. With a compact gear arrangement consisting of two sets of planetary gears, this transmission features a new electro-hydraulic control system which not only provides optimum shifting and lock-up points, but also modulates the hydraulic pressure electronically to achieve superior shift quality. Control over the transmission is integrated with engine control to deliver improved driveability and better fuel economy. Different transmission variations have been developed to create a versatile lineup for rear-wheel-drive vehicles.

A CVT variator chain system is superior in transmission efficiency to a belt system because of its lower internal friction. However, a chain produces more noise than a belt due to the long pitch length of contact between the pulleys and rocker pins. This study focuses on optimization of the pitch sequence for reducing chain noise. The previous pitch sequence was suitably combined of links of different lengths to improve noise dispersibility for reducing chain noise. First, the object function was defined as the reduction of the peak level of 1st-order chain noise combined with a well-balanced the levels on the low and high frequency sides. Interior background noise consisting of road noise and wind noise have the characteristic that they increase as the frequency decreases.

A prototype navigation system with cellular phone access to an information service center was constructed and evaluated. Center personnel can also operate the system remotely, in addition to providing traffic information and information for more enjoyable travel. Real-time conversation with a center operator is also possible. The system was rated positively by most of the subjects, especially the real-time voice service. This paper describes the car navigation market and cellular phone market in Japan, the system configuration, evaluation results and possible solutions to problems in the system. It also touches on the outlook for future car navigation systems and information services.

This paper discusses the influence of variations in the vehicle deceleration curve on dummy injury criteria for a passive seat belt-restrained dummy using MVMA-2D crash victim simulation and sled tests for frontal crash analysis. The MVMA-2D simulation and sled tests verified that the vehicle deceleration curve exhibiting the higher Residual Deformation (RD) produces smaller dummy injury criteria. Also, using MVMA-2D simulation, the peak levels of the first and second waves were changed as parameters to ensure accurate evaluation of the influence of the deceleration curve on dummy injury criteria. Moreover, this paper also discusses Nissan's use of both occupant kinematic simulation and vehicle structural sisulation for frontal crash in the development of its vehicles.

This paper describes a control method to improve straight-line stability without sacrificing natural steering feel, utilizing a newly developed steering system controlling the steering force and the wheel angle independently. It cancels drifting by a road cant and suppresses the yaw angle induced by road surface irregularities or a side wind. Therefore drivers can keep the car straight with such a little steering input adjustment, thus reducing the driver's workload greatly. In this control method, a camera mounted behind the windshield recognizes the forward lane and calculate the discrepancy between the vehicle direction and the driving lane. This method has been applied to the test car, and the reduction of the driver's workload was confirmed. This paper presents an outline of the method and describes its advantages.

This paper describes the improvement made to the high rigidity power-roller support structure in a dual-cavity half-toroidal CVT to further increase torque capacity. As a result of re-analyzing the function and parts composition of the previous structure, a high rigidity power-roller support structure, which permits power roller movement only in the horizontal direction, has been adopted. This structure enables the thrust and radial stiffness of the power-roller support to be substantially improved over the previous structure.

The influence on vehicle dynamics of braking force distribution to four wheels has been analyzed by computer simulation and experimentation. The analytical results indicate that a suitable braking force distribution control method can improve handling and stability during braking. A new braking force distribution cintrol strategy,using a steering wheel angle feedforward function and a yaw velocity feedback function,is shown to improve vehicle dynamic behavior.

Reducing vehicle fuel consumption has become one of the most important issues in recent years in connection with environmental concerns such as global warming. Therefore, in the vehicle development process, attention has been focused on reducing aerodynamic drag as a way of improving fuel economy. When considering environmental issues, the development of vehicle aerodynamics must take into account real-world driving conditions. A crosswind is one of the representative conditions. It is well known that drag changes in a crosswind compared with a condition without a crosswind, and that the change depends on the vehicle shape. It is generally considered that the influence of a crosswind is relatively small since drag accounts for a small proportion of the total running resistance. However, for electric vehicles, the energy loss of the drive train is smaller than that of an internal combustion engine (ICE) vehicle.

The application of both high strength gear steels and shot peening technology has succeeded in strengthening automotive transmission gears. This technology, though, improves mainly the fatigue strength at the tooth root, but not the pitting property at the tooth face. Therefore, demand has moved to the development of new gear steels with good pitting resistance. In order to improve pitting resistance, the authors studied super carburizing which is characterized by carbide dispersion in the case, especially processed with a plasma carburizing furnace. Firstly, the influence of the carburizing temperature and carburizing period on the carbide morphology was investigated and the optimum carburizing conditions were determined. Secondly, the fatigue strength and pitting resistance was evaluated using carbide dispersed specimens.