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Technical Paper

Wear Mechanisms of Methanol Fueled Engine

The wear mechanisms of the methanol engine were studied using dynamometer tests. Formic acid from methanol combustion mixes with the lubricant oil and attacks the metal surfaces. The iso tacho prorissis method was successfully applied to analyze the formic acid content of the used oil. A large amount of condensed water is also formed by methanol combustion and accelerates the wear. Wear can be effectively reduced by shortening lubricant oil change intervals, by using a special oil and by durable surface treatment of engine parts.
Technical Paper

Using the Modal Response of Window Vibrations to Validate SEA Wind Noise Models

The SEA model of wind noise requires the quantification of both the acoustic as well as the turbulent flow contributions to the exterior pressure. The acoustic pressure is difficult to measure because it is usually much lower in amplitude than the turbulent pressure. However, the coupling of the acoustic pressure to the surface vibration is usually much stronger than the turbulent pressure, especially in the acoustic coincidence frequency range. The coupling is determined by the spatial matching between the pressure and the vibration which can be described by the wavenumber spectra. This paper uses measured vibration modes of a vehicle window to determine the coupling to both acoustic and turbulent pressure fields and compares these to the results from an SEA model. The interior acoustic intensity radiating from the window during road tests is also used to validate the results.
Technical Paper

Thin wall and lightweight cylinder block production technology

The automobile industry currently faces many challenges which may greatly impact on its foundry operations. One of these challenges, consumers'' demand for greater fuel efficiency, can be met by reducing the weight of castings used in automobiles, and minimizing engineering tolerances. In answer to this particular demand, engine foundries have begun to either produce cylinder blocks or other castings with aluminum rather than cast iron. However, if a reduction in weight (thin wall and near-net shaping) can be realized with cast iron, there would be numerous merits from the perspective of cost and compactness and there would be much more flexibility in automotive parts design.
Technical Paper

Study on Combustion Chamber Deposit Formation Mechanism -Influence of Fuel Components and Gasoline Detergents-

The combustion chamber deposit (CCD) forming tendency of gasoline components and detergents were investigated with laboratory tests ad engine dynamometer tests. In the dynamometer tests, the driving conditions under which fuels and detergents influence CCD formation were specified, and the effects of different gasoline components and detergent blends on CCD formation were examined. In the laboratory tests, the CCD forming process was investigated thoroughly [10]. The CCD forming tendency of aromatic compounds in gasoline were dependent not only on physical properties such as molecular weight, but also chemical structure (number or position of the alkyl substituents of aromatic molecules). As for oxygenates, engine dynamometer tests with MTBE blended gasoline yielded less CCD than the test without MTBE. The CCD forming tendency of detergents correlated with the thermal decompositon tendency of the detergent package and the concentration of the main agents.
Technical Paper

Silicon Nitride Swirl Lower-Chamber for High Power Turbocharged Diesel Engines

This paper describes application of sintered silicon nitride to the swirl lower-chamber in order to improve performance of turbocharged diesel engines. Various stress analyses by finite element method and stress measurements have been applied to determine the design specifications for the component, which compromise brittleness of ceramic materials. Material development was conducted to evaluate strength, fracture toughness, and thermal properties for the sintered bodies. Ceramic injection molding has been employed to fabricate components with large quantities in the present work. Quality assurance for the components can be made by reliability evaluation methods as well as non-destructive and stress loading inspections. It is found that the engine performance with ceramic component has been increased in the power out put of 9PS as compared to that of conventional engines.
Technical Paper

Recycling Technology of Surface Material for Interior Trims

Two-layered surface materials composed of a thermoplastic olefin elastomer (TPO) skin and a cross-linked polypropylene (PP)foam are increasingly replacing the conventional PVC skin/PVC foam for interior trims. In the past, recycled material obtained by melt-blending TPO skin and PP foam could not be re-used for TPO skin because of its appearance. A new recycling technology using the reaction biaxial extruder with a reaction agent can decompose the network structure of PP foam. As a result, PP foam is dispersed into TPO uniformly and the recycled material has properties and an appearance similar to virgin TPO. These new properties may allow the application of the recycled material as a surface material.
Technical Paper

Recent Developments in Vehicle Interior Noise Reduction

In order to reduce the interior noise of a vehicle with a four-cylinder engine, investigations were made using finite element and vector methods, acoustic intensity testing and holography technique. The investigation resulted in inclination of the engine mounting, design changes to the front suspension member, a shock absorber engine mounting, structural modifications to reduce body panel vibration and a new engine mounting to insulate high frequency engine vibration.
Technical Paper

Prediction of the Life of CVJ Boot in Design Stage and Establishment of an Optimal Design Method with FEA

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.
Technical Paper

Prediction of the Airflow Through Automotive Radiators Using 3-Dimensional Analysis

Air flow around a car front end configuration and through the radiator and condenser was computed simultaneously. Although the engine compartment was simplified to reduce computational cost, comparison of experimental data with the analysis showed excellent prediction of the air flow through the radiator and condenser.
Technical Paper

Plasma Treatment for Painting of Polypropylene Bumper

The colour painting of polypropylene bumpers has required development of a new polypropylene surface treatment which provides improved adhesion of the paint film to polypropylene. According to the results of various improvement studies on the application of plasma treatment, it has been discovered that surface treatment by means of plasma of an oxygen and nitrogen gas mixture activated by microwave (2,450 MHz) provides a remarkable improvement in adhesion. Furthermore, establishing a technique to diffuse plasma effectively within the treatment chamber has enabled a uniform surface treatment of several polypropylene bumpers formed in large and complicated shapes.
Technical Paper

Nylon 6-Clay Hybrid - Synthesis, Properties and Application to Automotive Timing Belt Cover

ϵ-caprolactam was polymerized in the interlayer space of montmorillonite, the clay mineral yielding a nylon-clay hybrid (NCH). X-ray and TEM measurements revealed that each template of the silicate, which was 1 nm thick, was dispersed in the nylon 6 matrix, and that the interlayer distance of clay increased continuously from 1.2 nm for the unintercalated material to 21.4 nm for the intercalated material. Thus, NCH is a polymer-based molecular composite or a nano-composite. NCH contains 1-15 vol% of monolayer clay. Injection-molded NCH showed excellent mechanical properties compared with nylon 6 in terms of tensile strength, tensile modulus and heat resistance. The tensile modulus of NCH was twice that of Nylon 6, and the heat distortion temperature increased from 65°C for nylon 6 to 145°C for the NCH containing only 1.6 vol% of a clay mineral. It was found that such excellent properties of an NCH system was due to the strong ionic interaction between nylon 6 and the silicate layer.
Technical Paper

New Plastic Coloring and Forming System

This paper describes a new plastic coloring and forming system. The system greatly reduces the time and amount of raw materials necessary for color changes, and eliminates the need for manual cleaning during a color change. This system is well-suited for small-lot production with frequent color changes, as well as for automated production systems. The system is being used by auto parts makers, and is practical in a variety of other fields involved with the coloring and forming of plastics.
Technical Paper

Method of Fatigue Life Estimation for Spot-Welded Structures

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.
Technical Paper

Measuring System of Transient Temperature Distribution on the Brake Disc Rotor

A system to measure transient temperature distribution on the brake disc rotor at high speed braking has been developed and its measuring principle and configuration were discussed in this paper. This system consists of two revolution sensors and two sets of optical fiber array, photoelectric elements, and microprocessor, which fiber array is so arranged that it faces the brake disc rotor. This new system has the following features: (1) Measuring is made using a visible radiation wavelength range for red hot temperatures higher than 550°C.
Technical Paper

Life Cycle Inventory Study of Automotive Fuel Tank

As a means of effectively incorporating the concept of “life cycle” for reducing the environmental impact of the automobile, we carried out a life cycle inventory study on a part-by-part basis. The targets of our study are the fuel tanks that are made of different materials and manufacturing processes. One is made of steel, and the other is made of plastic, both perform identical functions. Our evaluation study encompasses the period from the manufacturing of the main materials until the disposal of the tanks. The evaluation items consist of the amount of energy consumed and the emissions (of CO2, NOx, SOx, and PM) that are released into the atmosphere. The results show that the plastic tank poses a greater burden in terms of the amount of energy consumed and the CO2 and NOx emitted.
Technical Paper

Lateral Shake Analysis of Open Top Cars

This paper analyzes the vibration of open-top cars known as lateral shake. The characteristics of the phenomenon were identified by means of road tests and a test method called the shake test was devised to reproduce these characteristics in order that the respective roles of the suspension, body and engine could be determined. On the basis of the analysis findings, a simple but practical simulation model was realized and used to investigate various methods of reducing lateral shake. The simulations indicated that although changing the natural frequency of the suspension has little effect, increasing the natural torsional frequency of the body and/or utilizing the engine as a dynamic damper results in a significant improvement. Further experiments conclusively demonstrated that by optimizing the body structure in accordance with FEM analysis results and optimizing the spring constant of the engine mounts, the level of lateral shake can be halved.
Technical Paper

International Technical Transfer of Automobile Manufacturing

Automobile production technology has been transferred in the order of "automobile assembly technology", "automotive parts manufacturing technology" and "production preparation technology". Transfer of our "automobile assembly technology" has already been nearly 100% completed and, as the manufacture of local parts is promoted and our experiences to undergo model changes are widened, the transfer of "automotive parts manufacturing technology" and "production preparation technology" is making a steady progress. The most critical point that makes the technical transfer difficult is the small automobile markets in developing countries where it is impossible to acquire a sufficient production volume which permits satisfactorily low cost. Various measures to secure a sufficient production volume such as exports and complementation within regions have been taken so far, but any remarkable effect has not been achieved.
Technical Paper

Highly Functional Engine Testing Technology Using an Electric Motor Drive

In contrast to the sensory inspection conventionally performed on the firing bench during final assembly, a technology in which quality inspections are distributed throughout the engine assembly line by using an electric motor to drive the engine, has been developed. Through this process, combustion conditions can be quantitatively tested by component, and leak test conditions can be optimized. Consequently, defects can be detected and their causes identified at an early stage of assembly, thus accelerating the feedback of information to the appropriate process. The result, a level of product quality that is higher than through the conventional means.
Technical Paper

Finite Element Simulation of Stamping a Laser-Welded Blank

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.
Technical Paper

Effect of Dimensional Factors on the Life of Rzeppa Universal Joint

Certain dimensional factors and a method for evaluating dimensional errors have been developed to improve the service life of the Rzeppa universal joint. The Rzeppa joint Spalling life is extended by disposition of the balls on a constant velocity plane under loading conditions which include proper determination of the offsets of the ball grooves and the windows of the cage. The ball center containment ranges, which consist of the grooves of both inner and outer races, can be affected by dimensional miscalculation of components. Moreover, the extent of scatter in the ball center containment ranges has a remarkable effect on the Rzeppa joint service life.