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In 1990, The Japanese National Police Agency (NPA) planned a nationwide two-year research project including field experiments, “Travel Time Estimation and Prediction” aimed at realizing a reliable method of providing travel time information to drivers (1)*. The project was conducted by the Japan Traffic Management Technology Association and three system manufacturers (Sumitomo Electric, OMRON and Matsushita Communication) collaborated on research and experimental work. Several methods of estimating and predicting travel time were developed and evaluated in three major cities (Tokyo, Yokohama and Osaka). Four models, Sandglass, Delay Time, Auto Regressive and Neural Network Models were developed and evaluated using detector and license plate reader information, and field survey data in the three major cities. The first year evaluation results are described here.

This paper describes an Automobile Navigation System with Multi-Source Guide Information. One of the features of this system is accurate location detection, which uses refined map-matching method incorporating a high accuracy rotation sensor, Fiber Optic Gyroscope (FOG). The system shows the position of the vehicle on a CRT map display and can also provide useful information, such as the locations of hotels, golf courses, etc., by using a CD-ROM disc. In addition to this information, this system can play CD-ROM discs based on the CDCRAFT standard. By means of this standard, software vendors can produce multimedia entertainment, such as a sightseeing guide with voice. Also, this system can display road and traffic information from the roadside radio beacons of the Vehicle Information & Communication System (VICS). This navigation system has been installed in Nissan's 1991 model Cedric, Gloria and CIMA.

The joining process of silicon nitride (S13N4) turbine rotor and steel metal shaft was investigated. The process consists of brazing procedures with multi-layer metallizing and complementary steps involving shrink fitting and non-destructive tests. In the course of the brazing steps, preliminary investigations using small specimens were conducted on the formation of a highly strengthened interface at high temperature and thermal stress reduction, and superior high temperature strength and heat cycle resistance were obtained. Rotary tests at high temperature were successfully completed using the rotor joined by this process.

Oil-pump rotors with a trochoidal tooth shape have many advantages compared with others, but the trochoidal tooth shape has not been sufficiently analyzed theoretically. So it is very difficult for the pump designer to decide the specifications for the trochoidal tooth shape, and it is also difficult for the supplier to meet the pump designer's requirements. We have been conducting theoretical analyses of trochoidal gears for several years, and have developed a system for designing the tooth shape. We can rapidly design the tooth shape, which meets the requirements of the pump designer, and develop the market for trochoidal gears by using this system. This paper shows the outline of the theoretical analysis, the outline of oil-pump rotors attached to crank shafts in automobiles as an example of the development of trochoidal gears, and some test results.

Recently, SiCr clean steel wire for springs on automotive engine valves has been developed. This report describes the characteristics of valve springs subjected to a new manufacturing process using SiCr clean steel wire. The process developed by the authors is as follows: First, form a helical spring with SiCr clean steel wire. Next, quench using the distortion preventing technic --Marquenching--. Temper at a temperature lower than the conventional temperature. Shot peen to the surface layer of the spring. And lastly, polish electrolytically to remove micro surface defects formed through shot peening. Using this new manufacturing process, a valve spring with high fatigue resistance can be produced. At the test stress of 588MPa(τm)±490MPa (τa), the number of cycles to fracture was above 100 million, while the number of cycles to fracture was 4 million using the conventional process with the SiCr clean steel which has the best fatigue resistance for commercial use.

ABS sensor rings for automotive use are becoming smaller and thinner because of the demand for low cost and light weight. Such small thin parts are easier to break as they must withstand the same severe conditions as larger heavier parts. Superior elongation properties, after corrosion testing, are necessary for avoiding breakage and to obtain superior corrosion resistance. We have, therefore, developed such high performance P/M stainless steel with superior elongation and corrosion resistance. Conventional stainless steel has uniform pores on its inner surface which makes allows water penetration thus making corrosion worse and decreasing elongation. It is possible to increase corrosion resistance by changing pore structure (e.g. decrease continual pores) through the addition of special alloys that accelerate the sintering process.