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By developing a mechanical-firing sensor using rotational inertia effect, we have completed miniaturization of the sensor and have developed a new-type mechanical-firing airbag system. This airbag system has been confirmed to have superior occupant protection performance after conducting a variety of vehicle crash tests and sled tests.

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.

Airflow effect is one of the important functions demanded of a rear spoiler. It helps prevent mud or dust from swirling up behind the running vehicle, or in the case of driving in the rain or snow, helps prevent rain or snow from adhering to the rear window. During the design process, we often decide on the shape of a spoiler in a relatively short time, focusing primarily on its appearance. Therefore, we established a design method using the recently developed computational fluid dynamics (CFD) to determine the central cross sectional shape of a spoiler that produces a desired airflow effect. We verified its effectiveness through testing.

Countries and regions around the world are tightening emissions regulations in reaction to the increasing awareness of environmental conservation. At the same time, growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. This catalyst incorporates rhodium (Rh) clusters with a particle size of several nanometers, and stabilized CeO2-ZrO2 solid-solution (CZ) with a pyrochlore crystal structure as a high-volume oxygen storage capacity (OSC) material with a slow O2 storage rate.

Diesel engines with relatively good fuel economy are known as an effective means of reducing CO₂ emissions. It is expected that diesel engines will continue to expand as efforts to slow global warming are intensified. Diesel particulate and NOx reduction system (DPNR), which was first developed in 2003 for introduction in the Japanese and European markets, shows high purification performance which can meet more stringent regulations in the future. However, it is poisoned by sulfur components in exhaust gas derived from fuel and lubricant. We then developed the sulfur trap DPNR with a sulfur trap catalyst that traps sulfur components in the exhaust gas. High purification performance could be achieved with a small amount of platinum group metal (PGM) due to prevention of sulfur poisoning and thermal deterioration.

These days, a variety of navigation systems have been developed to provide the driver with necessary information such as vehicle location, direction and destination. An electronic compass is being widely used as a component for such navigation systems (1), (2) and (3). Compared with a conventional magnetic compass, an electronic compass has the following advantages: 1. High vibration durability and quick response. 2. Easy to calibrate and reliable. 3. Sensor and display units can be separated. The electronic compass, however, is accompanied by two serious subjects: the development of a sensitive geomagnetic sensor, and calibration of direction error due to an unexpectedly magnetized vehicle body. First, we developed a new geomagnetic sensor utilizing magnetoresistive elements (MRE) and magnetic lenses. Next, we clarified the magnetic disturbances and defined the mechanism of vehicle magnetization, thereby establishing a simple calibration technique for such magnetization.

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.

New 2A/F systems different from usual A/F-O2 systems are being developed to cope with strict regulation of exhaust gas. In the 2A/F systems, 2A/F sensors are equipped in front and rear of a three-way catalyst. The A/F-O2 systems are ideas which use a rear O2 to detect exhaust gas leaked from three-way catalyst early and feed back. On the other hand, the 2A/F systems are ideas which use a rear A/F sensor to detect nearly stoichiometric gas discharged from the three-way catalyst accurately, and to prevent leakage of exhaust gas from the three-way catalyst. Therefore, accurate detection of nearly stoichiometric gas by the rear A/F sensor is the most importrant for the 2A/F systems. In general, the A/F sensors can be classified into two types, so called, one-cell type and two-cell type. Because the one-cell type A/F sensors don’t have hysteresis, they have potential for higher accuracy.

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 new method to measure in-cylinder flame propagation and mixture distribution has been developed. The distribution is derived from analyzing the temporal history of flame spectra of CH* and C2*, which are detected by a spark plug type sensor with multi-optical fibers. The validity of this method was confirmed by verifying that the measurement results corresponded with the results of high speed flame visualization and laser induced fluorescence (LIF) measurement. This method was also applied to analysis of cyclic combustion fluctuation on start-up in a direct injection spark ignition (DISI) engine, and its applicability was confirmed.

The development of the Lexus LFA focused on the pursuit of a passionate driving experience suitable for a super sports car. The shift speed control system in the LFA is an automated manual transmission (AMT) that uses an electrohydraulic actuator. The excellent shifting performance of the AMT was achieved by developing control technology that performs smooth, quick, and highly responsive shifting in accordance with the driving conditions. This was the result of repeated evaluations in both normal driving and on circuits featuring many acceleration, deceleration, and high-speed driving sectors. This paper describes the AMT shift speed control system and technology.

We have developed a new semi-active suspension, called Piezo TEMS, that uses piezoelectric ceramic for suspension control with sensor and actuator. It improves remarkably driveability with the firm damping force mode and enhances the ride comfort with the soft damping force mode immediately after the road surface input exceeding the threshold level.

In preparation for compliance with California's SULEV standard and Euro STAGE 4 standard, which will take effect in 2002 and 2005, respectively, we have developed a laminated planar oxygen sensor. The developed sensor has the following characteristics: high thermal conductivity and superior dielectric characteristic, due to direct joining of the heater element alumina substrate and the sensor element zirconia electrolyte; low heat stress at temperature rise, due to optimized heater design; superior sensor protection from water droplets, and improved sensor response, due to optimized arrangement of intake holes in the sensor cover. With these characteristics, the developed oxygen sensor can be activated in 10 seconds after cold start. This report describes the technologies we used to develop the early-activation oxygen sensor.

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.

Automotive catalysts with a good thermal durability have been developed by modifying the composition of additives. The stability of alumina supports against the loss of the surface area depends on the ionic radius and amount of additives. Some lanthanides and alkaline earthes with large ionic radii of 0.11-0. 15nm are most effective. Among these elements, lanthanum improves not only the alumina stability but the catalytic activities of rhodium and cerium oxide. Infrared spectroscopic studies show that lanthanum oxide affects NO adsorbed on Rh to improve the activity for NO reduction. Moreover, lanthanum forms the complex oxide with cerium to improve the activity of cerium oxide. CO pulse reactions on the complex oxide (Ce, La)O2 -x have proved that the oxygen defect in the lattice promotes the diffusion of oxygen atoms to improve the oxide activity.

The newly-developed 2JZ engine series is available in two types; a naturally aspirated 2JZ-GE and a turbo charged 2JZ-GTE. Both have in-Line-6 cylinder arrangement and displacement volume of 2.997 liters and have attained many features expected for the engines of new era by utilizing new technologies, such as DOHC 4 valve, high compression ratio, a highly rigid structural design which is realized by extensive use of the CAE, a serpentine accessory drive belt, and auto tensioners for timing belt and accessory belt systems. These engines are stroke up versions of the 1JZ engines. The 2JZ-GE engine, which has been developed for the SC300, delivers high performance of 169 KW/6000rpm and 284 Nm/4800rpm by adopting a variable induction system, a knock-control system with two sensors, etc. The other type, the 2JZ-GTE engine which has been developed for the Aristo in japan includes a TWO-WAY-TWIN-TURBO’ system equipped with ceramic turbine wheels.

In today's manufacturing environment, it has become necessary to develop intelligent robots which are adaptable to changing process requirements. To attain this goal, a key robot technology involving new real time control algorithms has been developed. The algorithms govern the 3D position and orientation of the robot. Initially, a simulation method was used to study the achievable system accuracy. From the results of computer simulations, it was determined that the algorithms can achieve a high tracking accuracy of ± 0.5 mm at a velocity of 300 mm/sec (4 times higher than conventional sensory control speeds). For a sensory feedback system, delays in tracking movements are inherent. This is due to the calculation time required for control and to the servo response. To solve this problem, a sensor is positioned at a predetermined distance in advance of the tool in the direction of travel.

Model-Based Development (MBD) has become an automotive industry standard process in vehicle control systems development due to the potential to reduce development time and improve engineering quality. This has become even more important as control systems are becoming increasingly complex while development cycle timelines shorten. Toyota utilized Hardware-in-the-Loop Simulations (HILS) techniques when developing the latest Fuel Cell Hybrid Vehicle, FCHV-adv. These MBD techniques contributed to the overall development process, but applications were limited to verifying control specifications. It was recognized that if MBD could be utilized beyond its current role in the control system design process to include functional specification validation, specification quality could be improved while decreasing development time and cost.

A new abdominal deformation measuring system for Hybrid III dummy has been developed in order to evaluate the abdominal injury by using the dummy. From the dynamic abdominal deformation of the dummy, the abdominal compression velocity V, the compression ratio C, and the maximum value of the product VC, expressed as [VC]MAX, can be calculated. This abdominal deformation measuring system consists of an abdominal insert having the same compression characteristics as those of the human body, a dynamic deformation sensor, and an analysis program. The abdominal insert is made of elastic foam rubber and has a shape fitted to Hybrid III. The deformation sensor in a band shape is a thin stainless steel band with 25 strain gauges on it. Each strain gauge measures the curvature on its mounted position. Since the deformation sensor is located along the surface of the dummy abdomen, the sensor deforms as the dummy surface deforms.

A control law for integrating 4WS and 4WD systems is presented. It is based upon a non-linear vehicle model in which the lateral force acting on the tires changes according to the tire slip angle, slip ratio and the load. The purpose of the system is to make the actual yaw rate follow the desired yaw rate. A two-degree-of-freedom control structure has been devised and variable transformation is used to linearize the non-linear model so that H∞ control theory can be applied to design the feedback compensator. A new control theory is used to calculate optimum command values for the 4WS and 4WD actuators. Moreover, adaptive logic is added to reduce the desired yaw rate as the tires approach the limits of adhesion. Simulations and experiments prove the system greatly improves stability during cornering.