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Technical Paper

32 Development of Silent Chain Drive System for Motorcycles

Examining the noise reduction of a motorcycle, the requirement of an effective method of reducing a drive chain noise has been a pending issue similarly to noise originating from an engine or exhaust system, etc. Through this study, it became clear that the mechanism of chain noise could be classified into two; low frequency noise originated from cordal action according to the degree of chain engagement and high frequency noise generated by impact when a chain roller hits sprocket bottom. An improvement of urethane resin damper shape, mounted on a drive side sprocket, was effective for noise reduction of the former while our development of a chain drive that combined an additional urethane resin roller with an iron roller worked well for the latter. The new chain system that combined this new idea has been proven to be capable of reducing the chain noise to half compared with a conventional system.
Technical Paper

3D-PIV Measurement and Visualization of Streamlines Around a Standard SAE Vehicle Model

In CFD (Computational Fluid Dynamics) verification of vehicle aerodynamics, detailed velocity measurements are required. The conventional 2D-PIV (Two Dimensional Particle Image Velocimetry) needs at least twice the number of operations to measure the three components of velocity ( u,v,w ), thus it is difficult to set up precise measurement positions. Furthermore, there are some areas where measurements are rendered impossible due to the relative position of the object and the optical system. That is why the acquisition of detailed velocity data around a vehicle has not yet been attained. In this study, a detailed velocity measurement was conducted using a 3D-PIV measurement system. The measurement target was a quarter scale SAE standard vehicle model. The wind tunnel system which was also designed for a quarter scale car model was utilized. It consisted of a moving belt and a boundary suction system.
Technical Paper

47 Development of a Titanium Material by Utilizing Off-Grade Titanium Sponge

Titanium alloy for forging and pure titanium material for exhaust systems have been developed. The forging alloy will be applied to production of lightweight motorcycle frames and the pure titanium will be applied to improve engine performance. The materials have been made inexpensive by the use of off-grade sponge that includes many impurities for production of titanium ingot. Stable characteristics have been obtained by controlling oxygen equivalent after setting the volume of tolerable impurities by considering mechanical properties and production engineering. In spite of low-cost, the material provides the same design strength compared to conventional material, and enables parts production with existing equipment. A review of manufacturing and surface treatment processes indicated a reduction in the price of titanium parts produced with this new material.
Technical Paper

A Study of Compatibility Test Procedure in Frontal Impact

The purpose of this study is to examine compatibility test procedures proposed in the IHRA Vehicle Compatibility Working Group. Various crash tests were conducted with different vehicle weights and stiffness in our previous study, and each of the compatibility problems, namely mass; stiffness and geometric incompatibility were identified in these tests. In order to improve the compatibility, it is necessary to evaluate and control relevant vehicle characteristics of compatibility in test procedures. According to the IHRA study, relevant aspects for compatibility in frontal impact are: Good structural interaction; Frontal stiffness matching; Maintaining passenger compartment integrity; Control the deceleration time histories of impacting cars.
Technical Paper

A Study of Forces Acting on Rings for Metal Pushing V-Belt Type CVT

Four forces act in rings for a metal pushing V-belt. These forces are: two kinds of intercepting forces which prevent blocks from going outside of pulleys (one caused by pulley thrust, the other caused by centrifugal force), frictional force acting between the rings and the blocks, and bending force in longitudinal direction. In the previous paper (1)(2)(3)(5), distribution of three forces, excluding centrifugal force, were presented at low belt speed. We successfully measured all four kinds of forces including centrifugal force continuously at practical operation conditions for layered rings. In this paper, distribution of these four forces on the innermost ring is described at steady states.
Technical Paper

A Study of a Metal Pushing V-Belt Type CVT-Part 2: Compression Force Between Metal Blocks and Ring Tension

In this study, distributions of block compression force on the driving and driven pulleys were measured using a tiny load-cell inserted between two blocks and a telemeter system, under several constant speed ratios. Ring tension distributions were also measured using a specially devised block. From the experimental results, the following conclusions were drawn: (1) Block compression force distribution on the driving pulley is significantly different from that on the driven pulley. (2) Ring tension takes different value at each side of strings. It is considered that this phenomenon is caused by difference of saddle surface speed between two pulleys.
Technical Paper

Acceleration of Iterative Vibration Analysis for Form Changes in Large Degrees-of-Freedom Engine Model

Operational analysis of automotive engines using flexible multi-body dynamics is increasingly important from the viewpoint of multi-objective optimization as it can predict not only vibration, but also stress and friction at the same time. Still, the finite element (FE) models used in this analysis have large degrees-of-freedom, so iterative calculation takes a lot of time when there is form change. This research therefore describes a technique that applies a modal differential substructure method (a technique that reduces the degrees of freedom in a FE model) that can simulate form changes in FE models by changing modal mass and modal stiffness in reduced models. By using this method, non-parametric form change in FE model can be parametrically simulated, so it is possible to speed up repeated vibration calculations. In the proposed method, FE model is finely divided for each form change design area, and a reduced model of that divided structure is created.
Journal Article

Advanced Transient Simulation on Hybrid Vehicle Using Rankine Cycle System

A hybrid simulation model in the transient bench was developed to realize the characteristics of the transient behavior and the fuel economy equivalent to that of a real vehicle. The motors and the batteries that were main components of the hybrid vehicle system were simulated as constructive modules, the functions of which have the integrated control and the input/output (I/O) function with real components. This model enabled us to accommodate a variety of auxiliary (AUX) I/O flexibly. The accuracy of the model was verified by the transient characteristics of the engine and the fuel economy result through correlation with a mass-produced vehicle. Furthermore, the flexibility of the model to a variety of AUX I/O was examined from the simulation test of the vehicle equipped with the waste heat recovery (WHR) system.
Technical Paper

Aerodynamic Development of the New Honda FIT/JAZZ

This paper discusses the characteristic flow field of the new Honda FIT/Jazz as determined from the aerodynamic development process, and introduces the technique that reduced aerodynamic drag in a full model change. The new FIT was the first model to take full advantage of the Flow Analysis Simulation tool (FAST), our in-house CFD system, in its development. The FAST system performs aerodynamic simulation by automatically linking the exterior surface design with a predefined platform layout. This allows engineers to run calculations efficiently, and the results can be shared among vehicle stylists and aerodynamicists. Optimization of the exterior design gives the new FIT a moderate pressure peak at the front bumper corner as compared to the previous model, resulting in a smaller pressure difference between the side and underbody.
Technical Paper

Aerodynamic Performance Evaluation System at the Early Concept Stage of Automotive Styling Development Based on CFD

An aerodynamic styling evaluation system employed at an early automotive development stage was constructed. The system based on CFD consists of exterior model morphing, computational mesh generation, flow calculation and result analysis, and the process is automatically and successively executed by process automation software. Response surfaces and a parallel coordinates chart output by the system allow users to find a well-balanced exterior form, in terms of aerodynamics and exterior styling, in a wide design space which are often arduous to be obtained by a conventional CAE manner and scale model wind tunnel testing. The system was designed so that 5-parameter study is completed within approximately two days, and consequently, has been widely applied to actual exterior styling development. An application for a hatchback vehicle is also introduced as an actual example.
Technical Paper

Analysis for Influence of Inhomogeneity of Air-Fuel Mixture to Super-Knock Caused by Pre-ignition in Supercharged Direct-Injected SI Engine Based on Numerical Calculation

Nowadays, highly super charging is required corresponded to downsizing concept for improving thermal efficiency in direct-injected spark ignition (DISI) engine. However, highly super charging increases the possibility of super-knock caused by pre-ignition. Recently, in many studies, the reason of pre-ignition has been investigated but the reason why pre-ignition leads such strong knocking called super-knock has not been investigated. In DISI engine, it is estimated that there is more inhomogeneity of equivalence ratio and temperature of air-fuel mixture than it in port injection SI engine. In this study, factors which decide self-ignition timing was reviewed and the influence of inhomogeneity of air-fuel mixture to super-knock was investigated based on numerical calculation.
Technical Paper

Analysis of FM Multipath Distortion using Two-Stage and MUSIC Methods

Traditionally, the suitability of wireless terminals for automotive use has been evaluated by conducting repeated driving tests in actual environments. However, this method of evaluation has long presented issues, and the implementation of the method itself is today becoming increasingly challenging. A method of evaluating the suitability of terminals for onboard use by generating virtual radio wave environments on a PC has therefore been developed by applying a two-stage method to multiple-input multiple-output (MIMO)-over-the-air(OTA) evaluation. The radio wave propagation characteristics necessary for the generation of these virtual radio wave environments are set using the multiple signal classification method incorporating an RF recorder. The research discussed in this paper used these methods to analyze the effect of the multipath distortion rate on sound quality in the reception of FM broadcasts.
Technical Paper

Analysis of Stress Distribution of Timing Belts by FEM

A model of a timing belt analyzed by FEM (a general non-linear finite element program:ABAQUS) successfully confirmed the mechanism that generates belt cord stress. Analysis revealed a good correlation between the experimental and computed results of stress distribution of the belt cord. Through calculation, it was discovered that belts broke near the tooth root, which is the point of maximum stress of the cord.
Technical Paper

Analysis of the Pressure Drop Increase Mechanism by Ash Accumulated of Coated GPF

With accelerating exhaust gas regulations in recent years, not only CO / HC / NOx but also PN regulation represented by Euro 6 d, China 6 are getting stricter. PN reduction by engine combustion technology development also progresses, but considering RDE, PN reduction by after treatment technology is also indispensable. To reduce PN exhausted from the gasoline engine, it is effective to equip GPF with a filter structure. Considering the installation of GPF in limited space, we developed a system that so far replaces the second TWC with GPF for the TWC 2 bed system. In order to replace the second TWC with GPF, we chose the coated GPF with filtering and TWC functions. Since the initial pressure drop and the catalyst amount (purification performance) of coated GPF have a conflicting relationship, we developed the coated GPF that can achieve both the low initial pressure drop and high purification performance.
Technical Paper

Analysis on In-Cylinder Flow by Means of LDA, PIV and Numerical Simulation under Steady State Flow Condition

This paper describes the evaluation of flow characteristics inside a model engine cylinder using particle image velocimetry (PIV), laser Doppler anemometry (LDA), and numerical simulation by Partial Cells in Cartesian coordinate (PCC) method. The main goal of the study is to clarify the differences in the velocity characteristics obtained by these methods. The model engine head has a four-valve system. Single- and dual- valve opening conditions of the model engine head were tested by a steady flow test rig. The flow structures were completely different for these valve opening conditions. The mean velocities and their distributions obtained by the three methods show satisfactory agreement. However, there were differences in the turbulence intensities under several conditions and measuring positions. Taylor's hypothesis in the integral length scale of turbulence was also compared with single LDA and PIV measurements.
Technical Paper

Anti-Shudder Property of Automatic Transmission Fluids - A Study by the International Lubricants Standardization and Approval Committee (ILSAC) ATF Subcommittee

In recent years, the slip lock-up mechanism has been adopted widely, because of its fuel efficiency and its ability to improve NVH. This necessitates that the automatic transmission fluid (ATF) used in automatic transmissions with slip lock-up clutches requires anti-shudder performance characteristics. The test methods used to evaluate the anti-shudder performance of an ATF can be classified roughly into two types. One is specified to measure whether a μ-V slope of the ATF is positive or negative, the other is the evaluation of the shudder occurrence in the practical vehicle. The former are μ-V property tests from MERCON® V, ATF+4®, and JASO M349-98, the latter is the vehicle test from DEXRON®-III. Additionally, in the evaluation of the μ-V property, there are two tests using the modified SAE No.2 friction machine and the modified low velocity friction apparatus (LVFA).
Technical Paper

Application of HIL Simulations for the Development of Vehicle Stability Assist System

The Vehicle Stability Assist (VSA) system can generate sufficient forces to rapidly change the vehicle's motion. We can use this capability to effectively control the vehicle's behavior, but we must pay careful attention to ensure its reliability. The VSA system should be precisely tuned for each vehicle's characteristics in order to satisfactorily control performance without any unnecessary intervention or any excessive warnings. Usually extensive field tests are necessary to precisely tune the VSA system. This paper presents a practical method to tune the VSA system with Hardware-In-the-Loop (HIL) simulations in the final stage of its development. Due to the application of this procedure, both high control capabilities and reliability of the VSA system can be achieved.
Technical Paper

Application of Load Path Index U* for Evaluation of Sheet Steel Joint with Spot Welds

An attempt was made to apply the index U* in detail analysis of load paths in structural joints under static load, using as examples coupling structures of two joined frames with hat-shaped sections, and T-beam joint structures each including spot welds, both of which are widely used in automotive body structures. U* is a load path analysis index that expresses the strength of connection between load points and arbitrary points on a structure. It was possible to identify areas making up load paths by means of the magnitude of U* values, and to clarify the areas that should be coupled in order to achieve effective load transfer to contiguous members. In addition, because it is possible to determine whether or not each section of a structure possesses the potential for load transfer using U* analysis, the research also demonstrated that U* could be used as an indicator of joint structures providing efficient load transfer.
Technical Paper

Application of Road Load Prediction Technique for Suspension Durability Input Condition

The aim discussed in this paper is to show a technique to predict loads input to the wheels, essential to determining input conditions for evaluation of suspension durability, by means of full vehicle simulations using multi body analysis software Adams/Car. In this process, model environments were built to enable reproduction of driving modes, and a method of reproducing the set-up conditions of a durability test vehicle was developed. As the result of verification of the accuracy of the simulations in the target driving modes, good correlation for waveforms can be confirmed. And also confirm a good correlation in relation to changes of input load due to changes in suspension specifications.
Technical Paper

Computer simulation process for pedestrian protection structures

Research into pedestrian protection has been carried out since the 1960s, in recent years there have been proposals in Europe to legislate requirements in this area and therefore the research is becoming more focused. In the draft regulation, impactor tests have been proposed as a method for evaluating the impact caused by vehicles'' body for pedestrians. This paper introduces impactor model and actual vehicle analysis as a means for simulating impactor testing. Three types of impactors for vehicle tests are presented. It is necessary that the models are first matched with the results of the calibration tests, then matched with the results of the tests on actual vehicles.