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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 Hybrid FE-SEA method has been used to create fast/efficient model of structure-borne noise in a fully trimmed vehicle from 200Hz to 1kHz. A joint paper is presented which highlights the method and modelling process along with extensive validation results. This paper describes the use of the model to analyze structure borne noise in the full vehicle, design and evaluate the impact of counter-measures. One of the key attributes of the Hybrid FE-SEA method is the ability to predict noise transfer paths in the vehicle. First, results from a Noise Path Analysis are used to identify key contributors to interior noise in the 200Hz-1kHz frequency range. Next potential design strategies for reducing interior noise are introduced along with implications on the model. Finally, sample prediction results illustrating the impact of design changes on interior noise levels are shown along with preliminary experimental validation results.

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.

The new Nissan 1.7 liter 4 cylinder diesel engine has been developed to meet the social requirements for energy conservation. The main objective was to improve fuel economy without sacrificing driveability, and this has been achieved by minimizing engine weight, reducing mechanical friction loss and optimizing the combustion system. The CA series gasoline engine, which is known for its light weight, was chosen as the base engine for dieselization. The swirl chamber combustion system used for the LD28 engine was modified to satisfy the requirements for high power, good fuel economy and low noise. Engine noise has been reduced with the aid of several analytical methods such as laser holography. Special attention has been paid to the reduction of diesel knock which is most offensive to the ear. To install this engine in a small FWD vehicle transversely, much effort went into the minimizing of the engine length and width.

The suspension system of the Nissan Stanza was specifically designed for use on a front-wheel-drive car. It was developed with the idea that the new suspension should be compact and light, and afford a comfortable ride as well as good stability and controllability. Furthermore, it should have excellent noise and vibration characteristics. To achieve these objectives we adapted a strut suspension for both the front and rear, and careful consideration was given to the fundamental specifications. In addition, some new ideas were applied for the layout of the suspension.

This Paper Presents the world's first active noise system for production vehicle implementation. Adopted in the new middle size FF car model, this epoch-making system dramatically reduces the booming noise caused by the second-order harmonic of engine revolution. This is accomplished by using an adaptive control theory based on digital signal processing technology and a digital signal processor (DSP). The system basically employs a multiple error filtered-x LMS algorithm, to which an new algorithm was added to achieve the maximum noise reduction effect under a condition of stable control in a compact system for production vehicle application.

The DATSUN 28OZ has been widely known as a world-wide sports car. The NEW DATSUN 28OZX, as the succeeding model to 28OZ, has now appeared after being refined on both interior and exterior design. The Suspension and steering system of the new model are improved to get better handling performance and lower noise level. In this paper, the design concepts and techniques of the new suspension and steering system are described. The main themes are as follows the construction of new suspension and steering system handling performance directional stability vibration and noise level

New image processing procedures for speckle photography and holographic interferometry are described. The algorithm for speckle photography measures the displacement value and direction automatically within the accuracy of ±5% over a range of 10 µm to 150 µm. This algorithm has adopted the Maximum Entropy Method to measure fringe intervals with high accuracy. The algorithm for holographic interferometry detects the fringe line and determines the displacement distribution with an operator's assist. Through the experiments, it was shown that these procedures are effective and accurate for vibration and deformation analysis.

Based on experimental analysis, the generation mechanism of abnormal exhaust noise which is characterized by an intermittent high frequency aetallic sound, is clarified by bench testing of a FWD vehicle. The noise is caused by large amplitude pressure waves (finite amplitude waves) in the exhaust pipe. They are amplified due to interference between reflected waves and subsequent waves from the engine, and are finally transformed into shock waves in the propagation process along the exhaust pipe, resulting in abnormal exhaust noise. By theoretical analysis of finite amplitude waves, the wave profile in the propagation process and the transition distance to the shock wave can be solved analytically where the assumptions of mass, momentum, and energy conservation are valid, until the moment of shock wave formation. The transition distance is a key parameter in analyzing the growth and existence of shock waves.

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.

Achieving a multi-cylinder engine with excellent noise/vibration character sties and low friction at the main bearings requires an optimal design not only for the crankshaft construction but also for the bearing support system of the cylinder block. To accomplish that, it is necessary to understand crankshaft system behavior and the bearing load distribution for each of the main bearings. Crankshaft system behavior has traditionally been evaluated experimentally because of the difficulty in performing calculations to predict resonance behavior over the entire engine speed range. A coupled crankshaft-block analysis method has been developed to calculate crankshaft system behavior by treating vibration and lubrication in a systematic manner. This method has the feature that the coupled behavior of the crankshaft and the cylinder block is analyzed by means of main bearing lubrication calculations. This paper presents the results obtained with this method.

Since interior noise has a strong effect on vehicle salability, it is particularly important to be able to estimate noise levels accurately by means of simulation at the design stage. The use of sensitivity analysis makes it easy to determine how the analytical model should be modified or the structure optimized for the purpose of reducting vibration and noise of the structural-acoustic systems. The present work focused on a structural-acoustic coupling problem. As the coefficient matrices of a coupled structural-acoustic system are not symmetrical, the conventional orthogonality conditions obtained in structural dynamics generally do not hold true for the coupled system. To overcome this problem, the orthogonality and normalization conditions of a coupled system were derived by us. In this paper, our sensitivity analysis methods are applied to an interior noise problem of a cabin model.

Increased attention has been directed toward noise and vibration characteristics of vehicles in recent years and the performance requirements in this area continue to become more rigorous every year. The acceleration noise in a frequency range of 250 ∼ 800Hz caused by powerplant vibration is important, and there is a need to reduce this noise level. In addition to reducing noise and vibration, however, there is also a growing need to achieve further weight reductions. Consequently, it is essential to reduce the weight of a powerplant without increasing its vibration levels. This make it necessary to predict powerplant vibration characteristics accurately at the planning and design stage so that suitable specifications can be determined. Specifications for reducing powerplant vibration have traditionally been found by experimentation. However, in powerplant excitation tests it has not been possible to take into consideration the effect of the crankshaft system on powerplant vibration.

One of advanced requirements in current high output power engine design, as is seen in a four valve engine, is to reduce the exhaust noise without a reduction in engine performance. In order to examine the relationship between output and exhaust noise level, a gas dynamics simulation model was extended so as to predict the exhaust generated noise. The gas dynamics model used in this study is developed based on a finite difference method in which unsteady compressible flow is solved by two-step Lax-Wendroff method. Using this simulation model, timing changes were found to be effective in reducing the exhaust noise level without showing any trade-off on engine performance. These results were validated by the experiment.

Road Noise is generated by the change of random displacement input inside the tire contact patch. Since the existing 3 or 6 directional electromagnetic shakers have a flat surface at the tire contact patch, these shakers cannot excite the vehicle in a manner representative of actual on-road road noise input. Therefore, this paper proposes a new experimental method to measure the road noise vehicle transfer function. This method is based on the reciprocity between the tire contact patch and the driver's ear location. The reaction force sensor of the tire contact patch is newly developed for the reciprocal loud speaker excitation at the passenger ear location. In addition, with this equipment, it is possible to extract the dominant structural mode shapes creating high sound pressure in the automotive interior acoustic field. This method is referred to as experimental structure mode participation to the noise of the acoustic field in the vibro-acoustic coupling analysis.

The front exhaust pipe and the heat-shield plate of the catalytic converter are excited by the engine vibration. Noise radiation occurs on their surface. Concerning vehicle exterior noise, noise radiated from the exhaust system is often one of major sources as well as engine and exhaust noise. This paper describes the longitudinal vibration model-as a beam-is applied to the high frequency vibration that causes the noise radiated from the exhaust system. It describes also some methods of reducing such noise radiation by isolating the vibration from the front exhaust pipe. These methods are: adding mass to the front pipe, changing the material of the front pipe to a smaller Young's modulus one, installing flexible pipe composed by two sections, and so on.

Design optimisation with respect to interior noise is currently a topic of great concern for the automotive industry. An essential element in this process is to obtain a correct understanding of the various noise sources which are present, and the ways in which these sources propagate to the critical receiver. An experimental source-transfer-receiver methodology is presented, that allows quantifying the structure borne and airborne source strength of the intake system components and its contribution to the interior noise. The method allows interior noise optimisation after identification of the dominant contributors. The methodology is applied to identify the noise contribution of the air intake system to the interior noise of an 8-cylinder upper class vehicle. Correlation of the Structure Borne Transfer Path Analysis and Airborne Source Quantification models with physical decoupling experiments demonstrates a high correspondence.

A seat vibration prediction technique using a substructure synthesis method was developed for use in ride comfort evaluations. The human body was modeled as a vibration transfer matrix using the mean apparent mass of human subjects, based on data measured in advance. Seat vibration characteristics were measured with rigid masses on the seat. The measured data and vibration transfer matrix of the human body were synthesized using a substructure synthesis method, to predict vibration of the seat cushion and backrest in an occupant-loaded condition without actually using human subjects. Results showed that seat vibration predicted with this method was very similar to, and more repeatable than, that obtained experimentally with human subjects.

In order to enhance product attraction, it is important to reduce the impact noise when a vehicle go over bumps such as bridge joints. Vehicle performance to transitional noise phenomena is not yet analyzed well. In this paper, a prediction method is established by vector composition and inverse Fourier transform with the combination of Multibody Dynamics (MBD) and FEM. Also, a root cause analysis method is established with the following three mechanism analysis methods; transfer path analysis, mode contribution analysis, and panel contribution analysis.