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A new test machine has been developed which can evaluate vibration due to stick-slip using an actual full-scale clutch pack. Using this machine, a static breakaway friction coefficient measurement test method and a stick-slip test method have been established. Both methods have been shown to provide results which correlate with the results from both a full-scale assembly test and a vehicle shudder evaluation test. The evaluation of the frictional properties of commercial oils using these test methods showed that the static breakaway friction coefficient and the stick-slip properties have generally contradictory performance to each other for automatic transmission. The study of the frictional properties for typical additives and an analysis of the surface of the steel plates with ESCA (Electron Spectroscopy for Chemical Analysis) showed that the frictional properties are significantly affected by the additives adsorbed on the clutch plate sliding surface.

The durability of an automatic transmission is greatly affected by its lubrication properties. However, it is difficult to estimate exactly the flow rate of lubricating oil at each part of the automatic transmission, because of its structural complexity under rotating conditions. This paper presents a simple model which can estimate the flow rate of lubricating oil in the automatic transmission. Using this method, we can obtain various information about the lubricating state at every part of the automatic transmission and can help our judgement of whether lubrication is sufficient. To test this model and its results, we tried some experiments and examined the lubricating state by measuring discharge rate of oil. The estimated data is in good agreement with the experimental data. This study should assist in the optimal design of the lubricating system in the automatic transmission.

In the field of automobile disk wheels, demands for aluminum wheels have been increasing for the reason of ride comfort and better appearance. And over 90 percent of luxurious passenger cars are equipped with aluminum wheels. This trend is spurred also by the demand for higher fuel efficiency for the cause of environmental protection, which calls for weight reduction of automobiles. This paper reports our research on manufacturing light-weight, high-quality aluminum cast wheels; covering the entire process from basic design to casting, and placing emphasis on the following three points. 1) Determination of optimum wheel configuration through computer simulation 2) Selection of optimum material composition 3) Optimization of the thin plate casting conditions Combination of the above technologies developed for the purpose of weight reduction resulted in the weight reduction of approximately 20% over the conventional aluminum wheels.

The purpose of this study is to analyze con-rod bearing lubrication under reduced oil supply rate conditions. An engine was modified to measure the oil supply rate to a con-rod big-end bearing. Then the effects of the oil supply rate on bearing temperatures and the contact between a journal and a bearing were investigated in order to analyze lubrication characteristics. The bearing temperatures increased in accordance with reduced oil supply rate. On the other hand, the contact frequency hardly changed under almost all conditions, but steeply increased near one-third of the standard oil supply rate at the highest speed of 5000 rpm in the experiments. The results show that the reduced oil supply rate decreases the cooling effect but the hydrodynamic lubrication was sufficiently achieved except the above-mentioned severe condition.

Various dies have been used for producing many internal and external parts of an automobile. This paper describes the method of ‘High Speed Die-sinking’ that is one of the key technologies for die-making. We analyzed the milling mechanism of a typical Ball End-Mill used for die-sinking and performed cutting tests. As a result, we have achieved high speed and fine quality die-sinking technology. Its feed speed is about four or five times as fast as before, and the irregularity of the milled surface is under one-fifth as compared with previous level. In addition, we will propose the new method for estimating finishing performance by ball end-mill.

Hybrid vehicles (HVs) are becoming more widely used. Since HVs supplement engine drive with motor power, the lubricant oil temperature remains at a lower level than in a conventional gasoline vehicle. This study analyzed the effect of cylinder bore temperature and lubricant oil temperature on engine friction. The results showed that, although the lubricant oil temperature was not relevant, the bore temperature had significant effect on piston friction. It was found that raising the temperature of the middle section of the cylinder bore was the most effective way of reducing piston friction.

Sintered silicon nitride, particularly in structural ceramics, has superior properties such as low weight, heat resistance, wear resistance, etc. It is already being applied to automobile engine parts such as the swirl chamber and the turbine rotor. In recent years, the strength of silicon nitride has shown to be above 1000MPa. This has been achieved through advances in manufacturing technology such as materials powder, forming, sintering and so on. But the silicon nitride is easily damaged during grinding because it has less fracture toughness than metal. Consequently, the inherent strength of the material is not demonstrated in the actual products presently produced. It is assumed that the main cause of strength reduction is microcrack. In ordinary grinding methods, the length of microcrack has been estimated at approximately twenty micrometers by fracture mechanics analysis.

Recently, single action draw with cushion replaces draw with double action presses. In the single action draw, binding fluctuation problem occurs by its structure. We applied an NC cushion to prevent the problem. We compared the cushion force wave with and without an NC cushion. The NC cushion showed effective damping. We studied the binding force control of a side member outer panel. The panel didn't have the formable range of binding. This means the lowest binding force to avoid wrinkling, still had crack problems. We introduce four patterns of binding force control with the NC cushion. As a result, we found the suitable pattern to suppress the surface distortion. Controlling the binding force shows effectiveness as a means of suppressing surface distortions.

A study of diesel fuel as a lubricant for diesel engines was conducted with the aim of dramatically reducing engine friction and eliminating the need to change the lubricating oil. A prototype single-cylinder engine modified for diesel fuel lubrication was made, and it was confirmed that firing operation is possible. Piston friction during the firing operation was reduced by modifying the shape of the cylinder liner surface to improve the retention of the lubricating oil. The study produced valid findings concerning engine lubrication, not only with diesel fuel, but also with ultra-low viscosity oil.

Piston ring moving zone in the cylinder is one of the most critical lubrication regimes in diesel engines. This area is susceptible to combustion substances. In particular, abnormal wear is occasionally detected due to Exhaust Gas Recirculation (EGR) system equipment. In Japan, NOx emission requirements for passenger car diesels have become more stringent effective October 1, 1986. OEMs tend to apply EGR systems to reduce NOx in exhaust gas. In order to identify the phenomenon of abnormal cylinder wear of EGR equipped engine, engine bench tests were conducted under varied conditions in EGR equipment, cooling water temperature and fuel sulfur content. The test results suggest that wear caused at low temperature is mainly corrosive wear attributable to sulfuric acid formed by reaction with fuel sulfur and condensed water.

The fluorescent magnetic particle inspection is widely used as a visual inspection method for checking cracks generated in hardening and grinding of induction-hardened parts. However, automation of this inspection process has strongly been demanded, due to poor environmental conditions and production line speed. To satisfy such a demand, we have developed a method for picking up images of automotive parts with higher S/N ratio and an original algorithm for image processing which helps measure cracks accurately without being affected by the illuminance and magnetic particle solution concentration. Then we selected the front axle shaft as the object to study practical use and have solved various technical problems in actual use, thereby succeeding in actual application to our production lines.

1G engine series consists of four types of 2-liter, in-line, 6-cylinder gasoline engines for passenger cars, with different performance characteristics to meet diversified market demands. These engines are already put into mass production. The original engine - 1G-EU - is a compact and light weight 2-valve OHC engine with the maximum power 77 kW/5200 rpm. The 1G-GEU is a 4-valve DOHC engine developed on the basis of the 1G-EU engine, with a higher performance and a higher power of 103 kW/6200 rpm. The 1G-GZEU is a mechanical supercharging type engine based on the 1G-GEU, with a remarkably improved performance in the low and medium engine speed ranges, and the highest power of 110 kW/6000 rpm. The 1G-GTEI! is a turbocharging type engine also based on the 1G-GEU, with a markedly improved performance in the medium and high speed ranges, and the high power of 136 kW/6200 rpm. A number of new technologies were introduced on development of these engines.

To more effectively improve the work on a vehicle assembly line, it is desirable to have a method by which the degree of work load on each person can be evaluated quantitatively; enables us to decide the priority order of improvement; and calculates the improvement effect. We developed a quantitative evaluation method of work load by introducing a concept of physiological stress generated regardless of the type of muscles involved. Applying the burden borne by the body to the load evaluation of various assembly operations involved the problem of complex load measuring methods. We solved this problem by categorizing the load conditions for various assembly operations and converting each to a standard state of loads evaluated by experiments.

Slip-controlled lock-up clutch systems are very efficient and greatly improve fuel economy. On the other hand, these systems can cause unstable vibrations including those known as “shudder vibrations”. In this study, the authors made a theoretical analysis of these unstable vibrations to clarify the fundamental frictional properties of automatic transmission fluids (ATFs) required for slip-controlled lock-up clutch systems. Based on this analysis, we established lubricant technology having a sufficient anti-shudder property and high torque capacity. Further, we developed a new test apparatus to evaluate the anti-shudder durability for lubricant development.

An unprecedented phenomenon that achieves high NOx conversion was found over an NSR catalyst. This phenomenon occurs when continuous short cycle injections of hydrocarbons (HCs) are supplied at a predetermined concentration in lean conditions. Furthermore, this phenomenon has a wider range of applicability for different catalyst temperatures (up to 800 degrees Celsius) and SVs, and for extending thermal and sulfur durability than a conventional NOx storage and reduction system. This paper analyzes the reaction mechanism and concludes it to be highly active HC-deNOx by intermediates generated from adsorbed NOx over the base catalysts and HCs partially oxidized by oscillated HC injection. Subsequently, a high performance deNOx system named Di-Air (diesel NOx aftertreatment by adsorbed intermediate reductants) was demonstrated that applies this concept to high speed driving cycles.

New ductile cast iron flywheel integrated with gear and its manufacturing process were developed to reduce the manufacturing steps and cost compared with conventional flywheel around which a steel ring gear is fit. In this process, the ring gear teeth around a cast iron flywheel are formed directly in net shape and free from any defect by the hot form-rolling method, followed by the thermomechanical treatment in a short time. The gear is superior to that made by the conventional hobbing and heat treatment in accuracy, strength and anti-wear property.

This paper presents an improvement in the accuracy of NOx sensors at high NOx concentration regions by optimizing the manufacturing process, sensor electrode materials and structure, in order to suppress the deterioration mechanism of sensor electrodes. Though NOx sensors generally consist of Pt/Au alloy based oxygen pump electrodes and Pt/Rh alloy based sensor electrodes, detailed experimental analysis of aged NOx sensors showed changes in the surface composition and morphology of the sensor electrode. The surface of the sensor electrode was covered with Au, which is not originally contained in the electrode, resulting in a diminished active site for NOx detection on the sensor electrode and a decrease in sensor output. Theoretical analysis using CAE with molecular dynamics supported that Au tends to be concentrated on the surface of the sensor electrode.

We have developed a new torsional damper spring which lowers the torsional rigidity of the clutch disc while retaining its conventional size. The following two items have been adopted in the newly developed spring: 1) A new steel wire which suppresses any core-softening of the element wire through nitriding. 2) A dual-stage shot peening method which uses harder steel shots (rather than conventional shots) in order to obtain an optimal residual stress profile. As a result of evaluating the fatigue characteristics of this spring, it was discovered that its fatigue strength is approximately 35% higher than that of the conventional spring. A clutch disc using this spring was able to absorb rattling noises which conventional clutch discs could not.

In conventional gasoline engine vehicles, three-way catalysts are used to simultaneously remove HC, CO and NOx from the exhaust gas. The effectiveness of the catalyst to remove these harmful species depends strongly on the oxygen concentration in the exhaust gas. Deterioration of three-way catalyst results in a reduction in its purification activity and OSC (oxygen storage capacity). In this investigation, additive elements were used to enhance the durability and OSC of the catalyst support material. An optimized formulation of a CeO2-ZrO2 and a ZrO2 material was developed to have excellent durability, improved OSC, enhanced interaction between precious metals and support materials, and increase thermal stability. Using these newly developed support materials, catalysts with increased performance was designed.

A high strength and high toughness new bainitic steel has been developed which shows comparable mechanical properties, fatigue property, and machinability to those of quenched and tempered SAE 5140. The heat treatment of the bainitic steel is aging after hot forging in order to improve ratio of 0.2% proof stress and tensile strength (i.e. yield ratio) and to avoid warpage associated with quenching. The new bainitic steel has been applied to the slender and lightweight lower arms for automotive suspension. As a result, the total production costs in the lower arms have been reduced by nearly 15 percent.