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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

Flow Noise Reduction upon Quick Opening the Throttle

With the advance in modularization of engine parts in recent years, there is increased use of plastic-made products in air intake systems. Plastic-made intake manifolds (Fig. 1) provide many advantages including reduced weight, reduced cost, and lower intake air temperatures. However, these manifolds have one disadvantage when compared with conventional aluminum-made intake manifolds, in that they transmit more noise because of their lower material density. For example, plastic intake manifolds of early development often generate flow noise when the throttle is opened quickly. With conventional aluminum intake manifolds, this flow noise had generated, but was not heard. This flow noise is presumed to be generated because of high-speed airflow generated when the throttle is opened quickly, but the mechanism of this noise generation has not been clarified.
Technical Paper

Modeling and Numerical Analysis of NOx Storage-Reduction Catalysts - On the Two Effects of Rich-Spike Duration

Two effects of rich-spike duration on NOx-storing have been analyzed. The first one, that NOx-storing speed decreases as rich-spike duration increases, is explained as the influence of NOx diffusion in wash-coat layer, which is quantified by a simple mathematical expression for NOx-storing rate. The second one, a peculiar behavior of NOx-storing in appearance of the outlet NOx concentration, is clarified: Heat produced directly or indirectly (via oxygen storage in ceria) by rich-spike warms up the downstream part, which releases excess NOx at the raised temperature. Contributions of the oxygen storage and the carbonate of NOx-storage material are also discussed.
Technical Paper

Plate Type Methanol Steam Reformer Using New Catalytic Combustion for a Fuel Cell

Methanol steam reforming, which is an endothermic reaction, needs some heating. Both methanol conversion ratio and carbon monoxide (CO) concentration increase when temperature is elevated. As CO poisons a typical polymer electrolyte of a fuel cell, the relationship between methanol conversion ratio and CO concentration is a trade-off one. It was found from preliminary researches that the reforming reaction speed is controlled by heat transfer rate at large methanol flow rate, where methanol conversion ratio becomes lower and CO concentration becomes higher. Therefore it is necessary to develop a new methanol reforming concept that provides stable combustion for heating and enhanced heat transfer for improving the trade-off relationship and making a compact reformer. Reforming catalyst using metal honeycomb support and a new catalytic combustion were applied to a new concept plate type methanol steam reformer, which is used in a fuel cell of 3 kW-class electric generation.
Technical Paper

Development of Multi-Layer Plastic Membrane (Bladder Membrane) for Vapor Reducing Fuel Tank

The Vapor Reducing Fuel Tank System (Bladder Tank System) using a flexible plastic membrane (Bladder Membrane) was newly developed in order to reduce the amount of vaporized gasoline in a steel fuel tank. This Bladder Membrane is flexible to expand in proportion to a fuel volume and prevents the permeation of the vaporized gasoline. As a result of our initial study for various materials, we decided to apply a multi-layer plastic material which could achieve both low fuel permeability and good flexibility. This multi-layer material consists of polyethylene(PE) for structural material and polyamide(PA) for low permeability. The modulus of the PE needs to achieve a sufficient flexibility in order to keep the movement of the membrane. While PA material must have not only low fuel permeability but also strong adhesion with the structural material of PE. We also clarify the membrane design to keep a good flexibility and to reduce a strain.
Technical Paper

Fuel Effects on Particulate Emissions from D.I. Engines - Precise Analyses and Evaluation of Diesel Fuel

Precise analytical methods for characterizing diesel fuel yielding the lowest particulate emissions were developed. The methods consist of preparative-scale high pressure liquid chromatography (HPLC), field ionization mass spectrometry (FIMS), analytical-scale HPLC, and carbon-13 nuclear magnetic resonance spectrometry (13C-NMR). A diesel fuel was first separated into an aliphatic fraction and an aromatic fraction by semipreparative-scale HPLC. Then, the aliphatic fraction was analyzed by FIMS and the spectrum was compared with that of the whole fuel. The aromatic fraction was analyzed by analytical-scale HPLC to obtain the chromatogram of the aromatic hydrocarbons with a high S/N. In addition to these analyses, the fuel was analyzed by 13C-NMR to obtain the concentration of the carbon atoms of the straight chain, branched chain and aromatic-ring in hydrocarbons.
Technical Paper

Trend toward weight reduction of automobile body in Japan

With society demanding automobiles that provide higher fuel efficiency, safety of occupants in collisions and that at the end of their service life can be recycled with low environmental impact, the steel industry is tackling the needs of the automobile industry by developing ever-higher performance steel materials and simulation technologies that can demonstrate the performance of steel materials at the development stage without the need for costly prototype testing. In this paper, weight reduction of automobile body in Japan will be discussed. The main items will be as follows: (1) Development of Automobile Steel Sheets, (2) Materials for Automobile Bodies, (3) Materials and Technologies (Tailored Blanks, Hydroforming and Locally Quenching) for Reducing the Weight of Panels and Reinforcing members, (4) Future Prospects.
Technical Paper

Development of Non-Lead-Added Free-Cutting Steel for Automobile Parts

A new, free-cutting steel, hereafter referred to as “non-lead-added free-cutting steel”, has been developed with the intention of replacing currently applied lead containing free cutting steel. The ultimate goal of this project is to provide a new lead-free steel grade that will contribute to the removal of environmentally harmful substances from automobile parts. In this project, we have targeted the development of a material that would demonstrate levels of machinability and other mechanical properties equivalent to those of the conventional free-cutting steel to which sulfur (S), lead (Pb) and calcium (Ca) or combinations, thereof have been added. The fine dispersion of sulfide, modified by adding Mg and Ca, is most effective in enhancing the chip breakability that would otherwise deteriorate due to the absence of lead. The practical application of the non-lead-added free-cutting steel has rendered the goal of total removal of lead from special steel products highly obtainable.
Technical Paper

Evaluation of the Corrosion Durability of Steel Systems for Automobile Fuel Tanks.

The Strategic Alliance for Steel Fuel Tanks (SASFT), an international group of steel producers and manufacturing companies, recently completed a major corrosion study of various steel ‘systems’ for automobile fuel tanks. The ten steel systems included low carbon steels (either pre-painted or post-painted with protective coatings) and stainless steels. The 2-year corrosion test program included testing in salt solutions to simulate road environments for the exterior of a fuel tank. Special test specimens were designed to represent a manufactured tank. The external tests used were the Neutral Salt Spray test (ASTM B117) with exposures up to 2000 hours and the Cyclic Corrosion test (SAE J2334) with exposures up to 120 and 160 cycles to represent vehicle lives of 15 years and 20 years, respectively. Additionally, the resistance to an aggressive ethanol-containing fuel (internal tank corrosion) was assessed by using uniquely designed drawn cups of the various steel systems.
Technical Paper

Comparison between Experiments and FEM Simulation of High Velocity Tensile Test Methods to Clarify Test Method's Influence of High Strength Steel

In order to examine the compatibility of improvement of crashworthiness with weight-saving of automobiles by using high strength steel, a combination analysis of Finite Element Method and Dynamic Mechanical Properties has been established. The material properties used in this analysis have been measured by “one bar method” high velocity tensile tests, which can examine the deformation behaviour of materials at an actual crash speed range (∼55km/h). As for the accuracy of this system, comparison between experiments and FEM simulation both of this test machine and other high-velocity-tensile-test machines have clarified the feature of one bar method and the metallurgical features of high velocity deformation. It was confirmed that the stress-strain curve measured by the one bar method agreed with that measured by the modified Split Hopkinson pressure bar method.
Technical Paper

Crashworthiness Improvement of the Side Crash by the Work Hardening Effect of Pre-Strained High Strength Steel

In order to examine the compatibility of improvement of crashworthiness with weight saving of automobiles by using high strength steel, a combination analysis of Finite Element Method and Dynamic Mechanical Properties has been established. Material properties used in this analysis have been measured by “one bar method” high velocity tensile tests, which can examine the deformation behavior of materials at a bend crush speed range (∼55km/h). It was confirmed that the strength of steel measured by one bar method was raised remarkably after press and hydro forming of high strength steels. It was also confirmed by FEM analysis and load drop test that absorbed energy of bend crush was improved by pre-strain effect. Further, we proved that absorbed energy of bend crush was also improved by appropriate design of thickness and the ratio of bend span and plate length. These effects are applicable to respective high strength steels.
Technical Paper

Development of Vapor Reducing Fuel Tank System

In succession to the world-first introduction of a mass production gasoline hybrid passenger car into the Japanese market in 1997, Toyota also has introduced an enhanced version of the above to the US and European markets in 2000. Upon introduction of Toyota Hybrid System (THS) into the US market, a drastic reduction of gasoline vapor evaporation from the fuel tank was necessary, in order to meet the most stringent exhaust emission (SULEV) and evaporative emission standards in the world. In order to meet this requirement, a fuel tank system named “Vapor Reducing Fuel Tank System” was developed. This is the first commercial application in the world to use a variable tank volume to drastically reduce gasoline vapor generation.
Technical Paper

Mechanism of the Smokeless Rich Diesel Combustion by Reducing Temperature

Recently, the smokeless rich diesel combustion had been demonstrated [1]. This can realize smokeless and NOx-less combustion by using a large amount of cooled EGR under a near stoichiometric and even in a rich operating condition. We focus on the effects of reducing diesel combustion temperature on soot reduction.
Technical Paper

Development of the Automotive Exhaust Hydrocarbon Adsorbent

The hydrocarbon adsorption volume character of zeolite was studied. Specifically, the relationship between aluminum content and zeolite hydrocarbon adsorption was investigated, as a potential hydrocarbon adsorbent for exhaust gas. The study also analyzed the relationship between hole diameter and zeolite hydrocarbon adsorption. It was found that hydrocarbon adsorption increased with decreasing aluminum content. Zeolite with a pore size approximately 0.1nm greater than the diameter of hydrocarbon molecules showed the best performance. Zeolites with two different pore sizes were mixed, and succeeded in adsorbing hydrocarbons of carbon number 3 and above. Silver (Ag) ion exchanged zeolite was also used to increase the adsorption of exhaust gas hydrocarbons, including those of carbon number 2.
Technical Paper

Simultaneous Measurements of the Components of VOCs and PAHs in Diesel Exhaust Gas using a Laser Ionization Method

A simple real-time measurement system for the components of volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs) in automobile exhaust gas using a laser ionization method was developed. This method was used to detect VOCs and PAHs in the exhaust gas of a diesel truck while idling, at 60 km/h, and in the Japanese driving mode JE05. As a result, various VOCs and PAHs, such as xylene and naphthalene, were simultaneously detected, and real-time changes in their concentration were obtained at 1 s intervals.
Technical Paper

A Study on Friction Materials for Brake Squeal Reduction by Nanotechnology

Brake squeal is caused by dynamic instability, which is influenced by its dynamic unstable structure and small disturbance of friction force variation. Recently, FE Analysis of brake squeal is applied for brake design refinements, which is based on dynamic instability theory. As same as the refinement of brake structure is required for brake squeal reduction, the refinement of pad materials is also required for brake effectiveness and brake squeal reduction. It is well known that friction film, which is composed of polymers like phenol formaldehyde resin and so on, influences for friction coefficient. Therefore it is expected that the refinement of polymers in pad materials enable higher brake effectiveness and less brake squeal. In this paper, Molecular Dynamics is applied for the friction force variation of polymers in pad materials. The MD simulation results suggest the reduction method of friction force variation of polymers.
Technical Paper

Development of High-Strength Aluminum Piston Material

Mass reduction of parts is growing in importance as a means for reducing CO2 emissions from vehicles.The aim of the present research was to contribute to further mass reduction of pistons by developing a new aluminum casting material with highest level of fatigue strength. This goal was achieved using a development concept of creating a homogeneous structure in which Ti was added to create a fine structure and appropriate quantities of Fe and Mn were added to form a compound that is stable at high temperatures. Stand-alone tests of prototype pistons fabricated using the developed material show that the material is 14% stronger than the conventional material, thereby enabling increases in power and mass reduction.
Technical Paper

Development of New Hybrid System for Compact Class Vehicles

Toyota has been evolving a hybrid system since introducing the first mass-production hybrid vehicle in 1997 in response to the increasing automotive-related issues of CO2 emissions, energy security, and urban air pollution. This paper describes a newly developed hybrid system design and its performance. This system was developed with the main purpose to improve fuel consumption, especially for better real world fuel consumption; and to enhance its compatibility with multiple vehicle adoption by downsizing and reducing the weight of its components. At the same time, the hybrid system achieved improved power performance while satisfying stringent emission regulations in the world.
Technical Paper

Improvement of NOx Storage-Reduction Catalyst

In order to further improve the performance of NOx storage-reduction catalysts (NSR catalysts), focus was placed on their high temperature performance deterioration via sulfur poisoning and heat deterioration. The reactions between the basicity or acidity of supports and the storage element, potassium, were analyzed. It was determined that the high temperature performance of NSR catalysts is enhanced by the interaction between potassium and zirconia, which is a basic metal oxide. Also, a new zirconia-titania complex metal oxides was developed to improve high temperature performance and to promote the desorption of sulfur from the supports after aging.
Technical Paper

Highly Efficient Hybrid Minivan with Super Low Emissions

This paper introduces a minivan with a newly developed hybrid system known as THS-C (The Hybrid System - CVT). This hybrid system employs a highly efficient engine, a high performance exhaust emission control system, a high efficiency metal belt CVT, and a super efficient motor. System control of the engine, motor and CVT optimizes the operation of both the motor and the engine. With these improvements, this new vehicle achieves over 80% better fuel economy than a comparable conventional vehicle. Exhaust emissions are dramatically reduced using precision control during the engine starts and stops.