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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.

An active suspension system controls a spring constant and an attenuater in real time using a power supply. Generally, the hydraulic pressures are used for transmitting the power. Therefore, a highly reliable and inexpensive control system has been required for a commercial use. This has been achieved by developing a mechanical fluid servo valve which comprises a simple combination of a solenoid valve and a spool valve. The technical problem of the valve vibrations has been solved through the numerical analyses, the fluid flow visualization tests and the vehicle tests.

In vehicle control systems such as ABS (anti-lock braking system) or active suspension control, sensors for detecting longitudinal and/or lateral acceleration of vehicles (acceleration of up to ± 9.8 m/s2, with frequency range of DC to 20 Hz) is necessary. The principle of acceleration detection for this sensor is as follows. A permanent magnet levitates steadily in magnetic fluid by the action of the magnetic field generated by the magnet itself. The magnet moves by the application of acceleration on the mass of the magnet. This change of position of the magnet is detected by the Hall element, and thus acceleration is measured as an electrical signal. This sensor consists of only magnetic fluid, a permanent magnet, housing, a pair of Hall elements and an electronic circuit.

In order to develop the valve rocker arm material for the new type engine, we investigated various materials whose chemical compositions were selected using 30% chromium cast iron, which had shown good results in screening evaluation tests, as the basis. High chromium cast irons are well known for their abrasive wear resistance, but it has been very difficult to apply them for use as rocker arm material because their machinability is very poor, and because it is difficult for them to have a regular microstructure. In this paper, both the manufacturing method for the rocker arm which decreases the disadvantages that high chromium cast iron have and the rocker arm material best suited for this method are described.

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.

Toyota has developed the world's first 8-speed automatic transmission (AA80E) for RWD automobiles. The transmission will first be used in the all-new Lexus LS460. In addition, a novel control system has been developed to maximize the predictability, response, efficiency, and initial quality of the powertrain while utilizing the high number of gear steps.

The torque converter clutch slip control system adopted in the Toyota A541E automatic transaxle engages the torque converter clutch by applying a steady slip speed to prevent the torque fluctuation of the engine to be transmitted to the drivetrain while enhancing the transmission efficiency of the torque converter. The feedback controller of the slip speed adopts the H∞ (H-Infinity) control theory which offers a high level of robust stability, and is the first of its kind in a mass produced component. As a result, a highly accurate and reliable system has been realized, contributing to large-scale fuel economy.

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.

This research developed a new measurement technology for thermal analysis of the heat radiation from a hybrid transaxle case surface to the air and improved the heat radiation performance. This heat flux measurement technology provides the method to measure heat flux without wiring of sensors. The method does not have effects of wiring on the temperature field and the flow field unlike the conventional methods. Therefore, multipoint measurement of heat flux on the case surface was enabled, and the distribution of heat flux was quantified. To measure heat flux, thermal resistances made of plastic plates were attached to the case surface and the infrared thermography was used for the temperature measurement. The preliminary examination was performed to confirm the accuracy of the thermal evaluation through heat flux measurement. The oil in the transaxle was heated and the amount of heat radiation from the case surface was measured.

One of the innovations for the Lexus LS400 is the development of a traction control system (TRAC system). The TRAC system suppresses the spinning of the driven wheels, which occurs easily on slippery roads during excessive acceleration, and it improves the acceleration performance and the stability of the car. The TRAC system controls the engine sub-throttle angle and the brake hydraulic pressure for the driven wheels in the same way as the traction control system for the 1987 Toyota Crown. But, acceleration performance and stability of Lexus LS400 is better than Crown as a result of good wheel spinning control by additional improvements of the throttle and brake control methods. Especially as the TRAC system controls the brake hydraulic pressure individually for left and right wheel, the car acceleration performance on split-μ surfaces is improved notably.

We have developed the world's first 8-speed automatic transmission for transverse FWD/4WD vehicles. The aim of this new automatic transmission was to achieve world-class fuel economy while offering both smooth gear shift and sporty shift feeling suitable for luxury cars. This has been accomplished using wide spread gear ratio, outstanding low drag components and highly efficient hydraulic control system. In addition, we have achieved the compactness similar to current 6-speed automatic transmission by adopting new gear train and compact clutch layout. In this paper, the detail of this automatic transmission is introduced.

Vehicles have been more required to save energy against the background of the tendency of ecology. As the result of improving efficiency of internal combustion engines and adoption of electric power train, heat loss from engine coolant, which is used to heat the cabin, decreases and consequently additional energy may be consumed to maintain thermal comfort in the passenger compartment in winter. This paper is concerned with the humidity control system that realizes reduction of ventilation heat loss by controlling recirculation rate of the HVAC system by using highly accurate humidity sensor to evaluate risk of fogging on the windshield. As the results of the control, fuel consumption of hybrid vehicles decreases and maximum range of electric vehicles increases.

This paper describes the preliminary development of an on-board integration network for vehicle dynamics. The underlying philosophy is explained and the basic requirements are set forth. A design conforming to these requirements is presented and the experiments conducted to optimise the physical layer are described. An original token passing protocol is proposed for the access method and evaluated in comparison with the contention method by means of a specially devised simulation system.

Roadway departure mitigation systems for helping to avoid and/or mitigate roadway departure collisions have been introduced by several vehicle manufactures in recent years. To support the development and performance evaluation of the roadway departure mitigation systems, a set of commonly seen roadside surrogate objects need to be developed. These objects include grass, curbs, metal guardrail, concrete divider, and traffic barrel/cones. This paper describes how to determine the representative color of these roadside surrogates. 24,762 locations with Google street view images were selected for the color determination of roadside objects. To mitigate the effect of the brightness to the color determination, the images not in good weather, not in bright daylight and under shade were manually eliminated. Then, the RGB values of the roadside objects in the remaining images were extracted.

A new automotive interior component material, TSOP-5 has been developed by refining the technology utilized to develop TSOP-1, the high modulus and high flow material for bumper covers. This new interior component material has excellent molding capability (MI=30dg/min.) yet still maintains high impact resistance which enables the material to be used in areas such as the dash board as well as trim covers requiring to meet the FMVSS 214, the new side impact regulation or the FMVSS 201, the new soft upper trim regulation.

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.

The change of the fuel flow rate in an injector with mileage accumulation causes poor drivability and exhaust emission deterioration in Otto-type methanol fueled vehicles with a multi-point fuel injection system. This is one of the serious problems which needs to be solved for the practical use of methanol fueled vehicles. The investigation results reveal that the wear of contact surfaces between a valve needle and a valve body increases the resistance force for valve needle movement and causes the change of dynamic fuel flow rate in the injector. The effects of several countermeasures to solve this problem are evaluated.

As the demand for improved fuel economy increases and new CO2 regulations have been issued, aerodynamic drag reduction has become more critical. One of the important factors to consider is cooling drag. One way to reduce cooling drag is to decrease the air flow volume through the front grille, but this has an undesirable impact on cooling performance as well as component heat load in the under-hood area. For this reason, cooling drag reduction methods while keeping reliability, cooling performance and component heat management were investigated in this study. At first, air flow volume reduction at high speed was studied, where aerodynamic drag has the greatest influence. For vehicles sold in the USA, cooling specification tends to be determined based on low speed, while towing or driving up mountain roads, and therefore, there may be extra cooling capacity under high speed conditions.

One-box type vehicles are especially liable to a loss of stability when entering a region of cross-wind. The reasons for this instability were investigated using scale models and by means of a mathematical simulation. Results indicated that yawing moment attains a peak at a precise position of the vehicle relative to the cross-wind. Visualization of the air flow and measurement of the pressure distributions established the cause of the phenomenon. Furthermore a study was conducted into the effects of body shape on stability and the efficacy of various modifications was assessed.

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.