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Engine friction reduction is an effective means to improve fuel consumption. Fluid friction reduction of main bearing is examined for engine friction reduction in cold condition. As one of the examinations, it was focused on low temperature of lubricating oil in the early stage during engine cold start. In hydrodynamic lubrication, the oil film temperature is maintained by balance between heat generation and heat transfer. The heat generation is generated by shear of lubricating oil. The factors of the heat transfer, the following elements are considered as follows, A) The heat transfer to a crank shaft, B) The heat transfer to a bearing, C) The heat transfer by convection. If the heat generation is constant, oil film temperature is increased by reduction of heat transfer. It is considered that the reduction of oil leakage and reduction of the heat transfer by convection is equivalent.

This paper deals with friction under wet condition in the disk brake system of automobiles. In our previous study, the variation of friction coefficient μ was observed under wet condition. And it was experimentally found that μ becomes high when wear debris contains little moisture. Based on the result, in this paper, we propose a hypothesis that agglomerates composed of the wet wear debris induce the μ variation as the agglomerates are jammed in the gaps between the friction surfaces of a brake pad and a disk rotor. For supporting the hypothesis, firstly, we measure the friction property of the wet wear debris, and confirm that the capillary force under the pendular state is a factor contributing to the μ variation. After that, we simulate the wear debris behavior with or without the capillary force using the particle-based simulation. We prepare the simulation model for the friction surfaces which contribute to the friction force through the wear debris.

The effect of phosphorus concentration in gasoline engine oils on the valve train wear was experimentally investigated by using the JASO M328-91 3A valve train wear (3A-VTW) test method. The phosphorus concentration is determined proportionally to the amount of zinc dithiophosphate (ZDDP), which is formulated as both antiwear agent and antioxidant. Lower concentrations of ZDDP generally bring about larger wear in the valve train. However, it was found from the experiments that valve train wear remained low despite a decrease of phosphorus concentration when secondary ZDDPs with short alkyl chain together with appropriate ashless dispersants were selected. Since adsorptivity of secondary ZDDPs with short alkyl chain lengths onto rubbing metal surfaces is higher than that of primary types, the secondary types give excellent antiwear characteristics.

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.

The relative oxidation stability of two fully formulated engine oils was compared in three testing methods by following the increase in kinematic viscosity of the oil. The purpose of the study was to determine the cause of the completely opposite ranking of the oxidation stability of the two oils that was observed in the ASTM Sequence IIIE engine test and the JASO M333 93 engine test and to determine the degree of correlation the two engine tests had with the field. The study consisted of laboratory oxidation testing, engine testing and taxi field testing to cover the range of conditions from controlled oxidation to actual driving conditions.

Previous studies and recent practical aerodynamic evaluations have shown that aerodynamic drag of passenger vehicles with “ground simulation” with moving ground and rotating wheels may increase in some cases and decrease in other cases relative to the fixed ground and stationary wheel conditions. Accordingly, the effects of the ground simulation on the aerodynamic drag should be deeply understood for further drag reduction. Although the previous studies demonstrated what is changed by the ground simulation, the reason for the change has not been fully understood. In this article, the effects of wheels and wheel houses attachment and those by the ground simulation with ground movement and wheel rotation on the aerodynamic drag were investigated by quantification of the underfloor flow that plays a crucially important role on the formation of vortical structure around vehicles.

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.

To reduse crosswind sensitivity, the yaw moment should be decreased under both transient and steady conditions. The transient condition is when a vehicle comes out immediately from a tunnel into a crosswind while the steady condition is when driving straight along the coastline. After studying the pressure distribution and the flow pattern around the body, we have reached the ideal air flow at the front-side corner that reduces the yaw moment under both conditions. And we have devised an entirely new method to achieve this better air flow. The method uses an internal flow generated by a pressure difference in the flow feeld to create a jet effect and by using only a duct for internal flow to control the outside air flow. It is done without any change to the exterior styling, except at the flow exit. We call it “Aero Slit”. This “Aero Slit” is effective only under crosswind conditions, and does not increase aerodynamic drag when a crosswind is not blowing.

A new partial strengthening method, TIG (Tungsten Inert Gas) remelting process, for automobile aluminum alloy castings is described. The preferable operating variables to strengthen, and metallurgical-mechanical properties of remelted alloys formed under selected conditions have been investigated. As a result, the mechanical properties such as strength and toughness, and thermal crack resistance of the remelted alloys were improved markedly due to the effects of microstructure refining and cast defects decrement by remelting. So, the application studies for automobile parts to meet the characteristics of this process have been carried out. Consequently, TIG remelting process has been practically used as an available strengthening method for the portion between valve ports of high performance diesel engine cylinder head.

A camshaft for an automobile engine is generally made of chilled cast iron. But, because of increased demand for higher performance engines, a camshaft with many camshaft has been expected. The cam intervals were necessarily narrow. So it was difficult to manufacture the conventional chilled cast iron camshaft at a moderate price. In the case of a rocker-arm type valve mechanism, higher wear resistance was necessary. After due consideration to solve these problems, development of surface remelted chilled layer camshafts by Toyota's unique manufacturing method has been accomplished. In 1984 Toyota Motor Corporation started the mass-production of this camshaft, first for the new 1.0 liter 1E engine, and then for the 1.3 liter 2E engine. In this paper, the excellent wear resistance, the low manufacturing cost and the characteristic manufacturing method are described.

According to the principle of pH measurement, an on-board type engine oil deterioration sensor has been developed. The developed sensor is composed of a Pb and oxidized stainless steel electrodes. The sensor signal shows a good linear relationship to the quasi-pH value of the oil. Especially in the region where the oil deterioration proceeds, the remaining basic additives in the oil is easily estimated from the sensor signal.

This paper describes the development of alloy cast iron that can be used for the cutting edges of the trimming die of a press die. Usually, a block of tool steel or steel casting is inserted at the cutting edge of the trimming die of a press die. However, we unified the structure part and the cutting-edge part of a press die with alloy cast iron. As it can''t bear as the cutting edge in this state, the cutting edge is processed by flame-hardening. After the flame- hardening, we developed the alloy cast iron so that enough hardness may be obtained by natural air cooling. Thereby, the machining of the installation seat of the cutting edge decreased and the expense of dies has been reduced.

In Toyota, a robot off-line programming system was developed five years ago for the use at spot welding processes. And it has been effective to reduce and level off the engineering time. This time we have developed the new robot simulation system. It has three newly features so that the system becomes capable of simulating and programming robots from various manufacturers with different functions. As a result, the new system can be applied to a variety of processes in automobile manufacturing. First, a universal robot programming language was developed which includes a variety of commands such as definitions of motion attributes, signals of inputs/outputs, control of program flow, special functions proper to each process, and so on. And the language can be translated to and from any particular programming language using pre / post processor, so the simulation system needs to deal with only one language.

Since the first robot: was introduced into our factory in 1971, about 1250 playback robots have been operated. But processes in which these robots were installed were limited to particular ones such as spot welding, are welding and painting. In many other processes robots have not been installed. Investing the reasons there is a main factor as follows, As to the application of robot, it is hard to evade the diversity of robot type because robots must be different from each other, if the most suitable robots are chosen in setting space, operating area, load capacity, speed and accurary against applied process and work pieces. If standard robots in the market are fitted to various conditions of processes or work pieces, the types of robots increase and many problems are produced on operation and maintenance.

The EMT (Elastomer Modified Thermoplastics) currently used in passenger car bumper fascia are limited in retaining low CLTE (Coefficient of Linear Thermal Expansion) and impact resistance, although they are highly rigid, which allows a reduction in weight, and also have high flowability during injection molding. We have developed a new bumper material called “Super Olefin Polymer” using a unique theory based upon a reversal of the current concept. The current polymer design concept of the EMT material is to compound and disperse the EPR (Ethylene Propylene Rubber) into the resin matrix such as polypropylene. We reversed the domain and the matrix, and treated the resin phase as the filler and the elastomer phase as the matrix.

In a two-loudspeaker stereophonic reproduction system of a passenger car, the geometrical configuration of the right and left loudspeakers has the disadvantage of being asymmetrical to the listener. For this system, we have made both theoretical and experimental verifications of the effects of strongly reflected sounds on the sound pressure level difference and phase difference between two ears which determine the location of sound image in a small compartment of a passenger car. On the basis of these verifications, we have developed a new sound localization control system. With this system, acoustical effects such as sound expansion and ambience have been greatly improved in a passenger car. In this system, input signals to the loudspeakers are controlled so that the sound image produced by the loudspeaker nearer to the listeners may acoustically move so as to position itself symmetrically with the other loudspeaker with regard to the listeners.

We developed a fastening method to reduce noise levels and fastening work loads. The development was based on research into improved tools and fasteners. This was done in preparation for an increase in elderly worker and female worker population in the Automobile Assembly Shop. The principle of this method is to form female threads inside a straight sleeve by clinching the sleeve around a threaded bolt. We achieved improvements in component material clinching force and a durability for loosening torque compared to conventional bolt and nut methods.

The camshaft for an automobile engine is generally made of chilled cast iron. Due to increasing demand for higher performance, lawer maintenance and better fuel economy, it is difficult to make the cast iron camshaft lighter and/or more durable. In order to overcome these problems, development of an integral camshaft comprised of a sintered alloy cam piece for better wear resistance and steel tube for weight saving has been accomplished. In 1981 Toyota Motor Corporation successively started the mass-production of the sintered intergral camshaft for the new 1.8 liter ls engine. The significant advantages are as follows; (1) Weight saving (2) Excellent wear resistance (3) Improvement of lubrication system (4) Saving machining cost

The transfer efficiency for painting processes utilizing water-borne materials is low, and the residual paint is disposed of as waste. In this study, we focused on a recycling system to collect and dissolve the paint over-spray in the booth water, and to concentrate and regenerate it by means of an ultra filter (UF). Paint adaptable to the recycling system has been developed by providing compatibility between the high hydrophilicity of liquid paint and the high hydrophobicity of the paint film, in order to ensure the recyclability and the high anti-corrosion performance required of paint on automobile underbody parts. This recycling technology is used in an actual propeller shaft painting process and provides large waste reduction and a decrease in painting cost.

One of the key elements of vehicle safety requires a constantly uninterrupted visible view especially during unexpected weather conditions. Our present development of a light reflection type rain sensor is a key device of our automatic windshield wiper system. The design concept of the sensor is based on the quantification on both detected rainfalls and wiping modes in order to match the wiping mode in an operator's mind by optimizing the optical sensing system and establishing an algorithm for controlling wiping. In addition, auto-initialization of the system has been achieved first in the world.