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Recently many automotive components have become electrified and an ultra high speed drive (over 150,000 rpm) is now expected in applications such as a turbocharger. In these applications, a robust induction motor (IM) with a rectangular wave drive is generally adopted. A speed sensor is required to control the IM, but it can cause problems concerning cost, space and reliability. Thus, a sensorless speed detection method is required. Because general sensorless methods based on a sinusoidal wave drive are not applicable to a rectangular wave drive, we propose a method utilizing slot harmonics that are generated by the mechanical structure of the IM. Signal-to-noise (S/N) ratio of slot harmonics is very small, and hence we suggest three techniques: a detection circuit, a digital filter with a variable passband, and a detection method to restart the motor while rotating.

We have developed a high-precision linear Hall sensor, which can detect absolute angles from 0 to 360°. In this sensor, novel vertical Hall elements have been used that can be fabricated using CMOS process technology, and the signal processing circuit is incorporated on the same chip. Using two vertical Hall elements placed precisely at an angle of 90° in the center of the chip, two-dimensional magnetic signals are detected. These signals are converted to an absolute angle by calculating the arc tangent of two Hall voltages. Moreover, this process compensates for the temperature dependence of these signals. Such a novel integrated vertical Hall sensor is promising for a wide range of applications.

To enhance drivers' convenience and safety, headlamps and headlamp control systems have been remarkably improved. For example, in daytime driving condition, auto-lighting systems support drivers especially when they repeat entering and exiting tunnels in mountain areas. On the other hand, in nighttime driving conditions, the higher luminance headlamp HID gives drivers the enhanced visibility and Adaptive Front-lighting System (AFS) offers them the increased forward visibility on curves. Nevertheless, their performances are not yet enough developed to meet the market demands. In case of entering tunnels, the lighting-up timing is sometimes later than desired. In case of HID and AFS, their potentials are sometimes unnecessarily restrained to prevent glare to oncoming vehicles even they don't exist. These problems should be solved by adding the scene sensor to those systems.

Inverter type electric compressors capable of providing cooling capability during engine stop and that do not cause fuel efficiency drop during air conditioning system use are recently being used in hybrid vehicles that have been drawing attention for their low fuel consumption and low emissions. Conventionally, the electric compressor inverter, like other high-voltage devices, was located in a cooling unit known as a power control unit (PCU) box because it requires cooling. However, inverter installation in the PCU box is subject to rigid installation constraints, and there is increasing need to integrate it with the electric compressors. In the present development, we adopted inverter-integrated construction in which the inverter is cooled using suction refrigerant etc., so as to make the electric compressor compact.

We have been developing the mixed-potential type NOx sensor which can detect the total-NOX concentration directly in exhausts for automobiles. It has been confirmed that the sensor is capable of detecting wide concentrations of total-NOx from 20 to 1000 ppm under the condition from rich-burn (A/F=12) to lean-burn without any interference from reducing gases, such as HC and CO. In addition, it has been confirmed that the sensor output is correlated fairly well to NOx concentrations from the analyzer in the engine test at any rotations. The results obtained here indicate that the present sensor has great possibility of being utilized as an on-board NOx sensor for practical use.

In recent years, new technologies have been developed and are being marketed with the aim of reducing the number of injuries and fatalities due to traffic accidents. They range from systems designed to reduce the driving burden to systems for controlling vehicles in the hope of mitigating the harm done by accidents when they do occur. One of the most important components in creating these systems has been a front obstacle detection sensor that detects obstacles in the paths of vehicles. DENSO is developing laser sensors, millimeter-wave radar, and vision sensors for front obstacle detection. Of these three, it is the laser sensors that have had the important role of supplying adaptive cruise control (ACC) to the market at a low price. This paper focuses on the laser sensor, the expansion of its applications, and the development of new technology to that end.

Regarding the prevention of global warming and ozone layer depletion to protect the global environment, energy conservation and disuse of CFCs are among the recent industrial requirements. An ejector cycle can save power by eliminating expansion energy loss in the conventional vapor compression refrigeration cycle, which uses an expansion valve, and using the otherwise lost energy as compressor power. This technology is useful for almost all kinds of refrigerating and air-conditioning systems, but has not yet been developed to a practical level anywhere in the world. We have developed a practical ejector cycle technology and successfully commercialized it for the first time in the world, as an ejector cycle refrigerator that drastically improves refrigerating capacity and power efficiency while substantially reducing system weight, in comparison with refrigerators using the conventional vapor compression cycle.

The environment is one of the most important issues currently facing the world and the automobile industry is required to respond with eco-cars. To meet this requirement, the hybrid vehicle is one of the most optimal solutions. The hybrid system automatically stops engine idling (idling stop), or stops the engine during deceleration to recover energy. The engine stop however creates a problem concerning the vehicle's climate control system. Because the conventional climate control system incorporates a compressor driven by engine belt, there is almost no cooling performance while the engine is stopped. Until now, when a driver needed more cooling comfort the engine has been switched back on as a compromise measure. To realize cabin comfort that is consistent with fuel saving, a 2-way driven compressor has been developed that can be driven both by engine belt while the engine is running and by electric motor when the engine is stopped.

In order to reduce traffic accident casualties, sophisticated safety systems have been developed and are continuously being upgraded in today's passenger vehicles. One system showing growth in the global automotive industry is a feature currently available on high-end passenger cars, Vehicle Stability Control (VSC). VSC can control side slipping, an unstable phenomenon which can lead to critical accidents. VSC systems are multi-functional systems that include an acceleration sensor to detect forces applied to the vehicle. Acceleration sensors sometimes referred to as G sensors are indispensable and are one of the key sensors for vehicle safety systems. New safety systems require acceleration sensors with high sensitivity and accuracy. We have achieved these increased requirements by adopting a unique stacked IC structure.

To meet diesel emission regulations, high injection pressure is demanded for the supply pump of electronically controlled common-rail type injection system. DENSO has produced common-rail type injection system in 1999. Cam and roller to generate high pressure in the supply pump at the system are composed of steel and silicon nitride ceramics, and are rolling contact under light oil lubrication. Therefore, rolling contact fatigue failure had been concerned. In order to assure the components, we estimated the influence on the materials and the lubrication on the rolling fatigue strength of silicon nitride ceramics, the contact fatigue life was tested under oil lubrication.

Phosphating is a surface treatment process widely used for preparing metal surfaces before painting. The phosphate coating plays a very important role in enhancing after-painting corrosion resistance, which is one of the essential quality requirements of painted surfaces. Continued research and development is therefore under way in various parts of the world to increase the corrosion resistance enhancement effect of phosphating. Moreover, because the demand for environmental protection has been increasing in recent years, reducing the amount of waste (sludge) generated during the phosphating process is also strongly required. To meet these requirements, we have developed a novel phosphating technology called the “electrolytic phosphating process,” which drastically enhances corrosion resistance after painting and reduces sludge generation. The developed process has already been put to practical use for surface preparation before cation electrodeposition painting of automotive parts.

Behavior of sprays formed by slit nozzle as well as swirl nozzles with the spray cone angle in the range of 40° ∼110 ° were studied in a constant volume N2 gas chamber. The fuels used are iso-pentane, n-heptane, benzene and gasoline. The ambient pressure and temperature were raised up to 1.0 MPa and 465 K, respectively. The injection pressure was mainly set at 8 MPa. Spray penetrates at an almost constant speed for a while after injection start and begins to decelerate at a certain point. This point was judged as breakup point, based on a momentum theory on spray motion, the observation of spray inside and the analysis of the spray front reacceleration which occurs under highly volatile condition.

In manufacturing technology, the predominant tendency in recent years has been for machine tools, for example, turning-, milling-, and drilling-machines, to employ an electrically operated actuator such as a servo-motor equipped with a ball screw. There are, however, various problems with these electric driving systems; they are excessively large in size and complex. In order to solve these problems, the first purpose of this study was to develop a precision driving system composed of a hydraulic cylinder and high-speed ON/OFF valves. It was confirmed that the developed system had a moving resolution of 1.2 μm. The second purpose of this study was to practice the ability test of turning, drilling and milling by applying the developed driving system to a micro-machine-tool. It was confirmed that the developed machine was compatible with, or even superior to conventional NC-machines.

As a means to reduce exhaust emission, narrowing nozzle hole diameter is known to be an effective method of improving fuel atomization. In general, Electrical Discharge Machining (EDM) is more effective than other machining techniques because there is no burring and no machining force is apply to the tool, but the drawback to EDM is a low removal rate. An EDM drilling device by using piezoelectric elements has been newly developed. This device can drive a wire electrode at a high response of 5kHz. As a result of high response, this device can drill holes 0.1-0.5mm in diameter 3 times more efficiently than a conventional electrical discharge machine.

This paper introduces the cruise control system with distance control function, that is called Adaptive Cruise Control (ACC), that uses a scanning laser radar as a sensor to detect preceding vehicles. With the goal of increasing the driving convenience and comfort when compared to the conventional cruise control, lots of ACC systems have been proposed and developed. This paper presents ACC system using the scanning laser radar which was developed by Toyota, and describes the adaptation of the system specifications. This ACC system was able to greatly reduce the driver's work load, and increased the driver's convenience and comfort when operating the cruise controls system. In addition, we were able to design this system to be highly dependable and inexpensive and supply it to the market as a result of incorporating various ideas for improvements.