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Researches and developments of electronic transmission control have been made along with the progresses of electronical technologies in order to meet the requirements of decreasing fuel consumption as well as improving drivability. And nowadays many kinds of electronically controlled transmissions have been applied to a variety of cars. In this paper, a history of electronic transmission control from the first control systems mounted on TOYOTA CORONA in 1970s for the first time in the world to the newest ones having a lock-up function for fluid coupling (Torque Converter) as well as progresses of the respective electronical transmissions to their practical uses will be explained.

A method of real time oil concentration measurment has been developed utilizing the effect of ultraviolet light absorption by lubricating oil in the liquid refrigerant line of an automotive air conditioning system. The light wavelengths from 200nm to 370nm are selected based on the ultraviolet light absorption sensitivity of the oils and refrigerants (CFC12,HFC134a). The effects of temperature,pressure and contaminantion on the absorbance of light are investigated in order to determine how these parameters affect the concentration measurement. The density changes of refrigerants are then compensated in the calculation for the oil concentration. The uncertainties of the overall concentration measurement are less than ±0.1 weight percent at 1 weight percent concentration. A transient oil circulation of the automotive air conditioner is measured by using this method.

Semi-active suspension is one of many effective devices to improve vehicle stability, controllability and riding comfort. A practical means to realize semi-active suspension is to vary the damping force of the shock absorber. In this paper, we propose a new type of shock absorber using a piezoelectric sensor and actuator. The piezoelectric sensor and actuator are built into the piston rod which is a part of the shock absorber. The piezoelectric element provides a fast response and a high actuation force. We used the piezoelectric element in shock absorbers in order to take advantage of these two features. High level compatibility between stability, controllability and riding comfort is expected, since damping force changes very quickly using this new type of shock absorber. In this paper, several topics are discussed. First, a general description of the damping force control system with simple configuration is explained.

As a part of a project to develop high performance, compact and lightweight vehicle radiators, a highly corrosion resistive fin has been developed, especially for use in the salt-laden environment. It is a thin plate with a mutual diffusion layer of Cu-Zn formed on either surface. Owing to this composite structure, not only the corrosion resistance is double that of Cu-Sn alloy fins that are currently in use with a thickness over 20% smaller than the latter (38 μm vs 50 μm), but the corrosion of the bonding solder has been reduced to one half because the Cu-Zn diffused layer has brought about substantial reduction in the fin's surface potential.

This paper introduces a new type of radiator that has been developed with the objective being, high performance (compact size), light weight, and high quality in the field of copper/brass radiators that are superior in heat conduction, lower in price, yet there is still more room for improvement. The development of a new copper/brass radiator with the objective being higher performance (more compact), lighter weight, and higher quality has been completed. The synthetic study covered is not only an in-depth analysis of performance and structure, but the new development of materials and production engineering. As a result, the new radiator has a minimum of 10% increased performance, a minimum of 25% weight reduction, and its corrosion resistance is more than twice that of a conventional radiator.

We have developed a highly corrosion-resistant serpentine type condenser which is characterized by its manufacturing process that zinc is coated on the surface of a multi-cavity extruded tubing at the rate of 5-20 g/m2 by arc spray, and then, thus prepared tubing and corrugated fin stocks are brazed by the conventional Nocolok brazing process (Herein after this is referred to as ZAS NB process). By this brazing process as well as conventional flux brazing (FB) process, a highly pitting corrosion-resistant zinc diffusion layer is formed on the surface of the tubing at the time when brazing is operating. This newly developed method achieved improvements in productivity and quality of product.

Instrument clusters used in automobiles play an important role as man-machine interface. A variety of information about the current driving situation is conveyed to the driver quickly and accurately. A great interest has been taken in the high visibility and legibility of the head-up display (subsequently abbreviated as HUD). Originally developed as display used in aeronautical applications, we have tried to exploit ways to adapt this device for automotive use. We have succeeded to produce a new HUD system, which has the following design features; (1) High brightness and high contrast display device using a liquid crystal display (subsequently abbreviated as LCD) and a halogen lamp illumination. (2) Long focus display in two colors using holographic lens. (3) Automatic dimming control system using an illuminance sensor. (see Fig. 1)

The effect of the amount of refrigerant on automotive air conditioning system behavior was clarified through simulations and experiments. It has been revealed that the best way to measure the amount of refrigerant in an air-conditioning system is to measure the liquid-gas flow ratio in the liquid line. In order to measure the liquid-gas flow ratio, a mechanical sensor for fluids was developed and applied to a refrigerant monitoring system which can identify when the amount of refrigerant drops to 60% of the regular level.

The authors developed a low-speed in-vehicle network for the body control system on passenger cars, where the most remarkable effects to reduce the number of wire harnesses could be expected. First, the authors analyzed the body control system to clarify the specifications required to build a low-speed in-vehicle network. Then the authors worked out optimum communication protocol, placing emphasis on cost reduction which is the key to expanding the applications of the low-speed in-vehicle network over wider fields. The low-speed in-vehicle network was evaluated for its performance through simulation and on-vehicle tests, and proved the practical validity of the concept. It was also verified that introducing the low-speed in-vehicle network has a satisfactory effect to reduce the number of wire harnesses.

1 Attenuation of acoustic noise from automobile components is important for passenger comfort. Since the alternator is one of the major sources of noise, many manufacturers have studied the various mechanisms which generate noise within an alternator as well as the methods to reduce the noise level. This paper presents the dynamic properties of the alternator with respect to the acoustic noise during current generation, and introduces a vibration damping structure based on experimental modal analysis. Rotating magnetic forces in a magnetic circuit (stator and rotor) can excite numerous structural resonances, resulting in acoustic noise. A modal analysis performed on the major magnetic circuit of the alternator (Nippondenso Co., Ltd.) revealed that the stator has elliptic, triangular and rectangular mode shapes in the radial coordinate plane, while the rotor does not have any significant resonances in the same 0 - 3 kHz region.

Environmental control of the passenger compartment has become increasingly important and sophisticated. One major consideration of interior comfort is clean, healthful, aromatic air. Accordingly, two new products were developed to increase the dust removing and deodorizing effects. These are the “Air Purifier” and the air conditioner ventilation filter called the “Air Refiner”. The Air Purifier affects the air inside the vehicle, and the Air Refiner affects the air from outside the vehicle. Remarkable effects are achieved by employing a newly developed material called “Impregnated Activated Carbon Fiber (IACF)” which is utilized in both the Air Purifier and the Air Refiner. In addition to the air purification system, a new fragrance control system called the “Aroma Controller” was developed. The Aroma Controller allows the user to select from three aromatic fragrances. The fragrance is emitted intermittently by way of “1/f fluctuation control” via microcomputer control.

As an alternative refrigerant for CFC-12, HFC-134a is the best choice in automotive air conditioning system. Refrigeration cycle characteristics using HFC-134a have been previously reported, but most of those papers were confined to the differences of basic system performance between CFC-12 and HFC-134a. So this paper emphasized the analysis on functional components. As a result, we have introduced the differences of refrigeration cycle characteristics which had not been acquainted well by now.

Concerns on environmental protection are being intensified throughout the world in recent years. Of those concerns, depletion of the ozone layer in the atomosphere caused by CFC emission into the atomosphere is the target of serious concern as shown in Fig. 1. At present, the use of CFC production is restricted by regulations at the global level, and CFC will be phased out by the end of 1995. In this regard, the authors have developed a new vehicle air conditioner to adapt to a new refrigerant HFC-134a, which is gentle to the ozone layer, and to replace CFC-12. The new refrigerant system was introduced to the market in October, 1991, and the replacement will be almost completed by the end of 1993 for the Lexus and Toyota production vehicles. This paper describes the development of the new compressor lubricant, seal rubber, hose and desiccant by taking into consideration the materials concerned and the number of technological issues involved in the new refrigerant, HFC-134a.

A highly corrosion resistant drawn cup type evaporator was developed. During the development of this evaporator, the corrosion characteristics of evaporators in the field were examined in detail. Profound understanding of the corrosion mechanism led to the development of a new, unique, corrosion test method which simulates the actual evaporator field service environment. The main factors involved in increasing the corrosion resistance of the brazing sheet are (1) reduction of iron and silicon content in the core alloy and, (2) addition of titanium to the core alloy. In the present alloy, titanium content varies lamellarly through the thickness of the core alloy. Regions of high titanium content have a more cathodic potential, thus causing corrosion to proceed along the low titanium content lamellae. Consequently, the reduced iron and silicon contents, and the titanium addition, have the net effect of reducing the pitting corrosion rate.

Extensive work was conducted to develop a corrosion resistant brazing sheet alloy and to apply it to a drawn cup type evaporator in automotive air conditioning system. The items to be investigated included the influence of chemical composition of the core alloy on corrosion resistance, suppression of erosion during the brazing cycle, and enhancement of the brazing sheet formability. Additional investigation was conducted to develop a new corrosion test method on the basis of better understanding of the mechanism of corrosion in the field and to evaluate the corrosion resistance of a evaporator fabricated from the new alloy. This paper, as Part 1, describes the results of alloy development from the metallurgical and electrochemical point of view.

In recent years, designers have attributed increasing importance to reducing noise in car interiors, and various improvements have led to a steady decrease each year in said interior noise. More recently, there has been abundant research on quantitative and qualitative approaches to interior noise, including studies on improving sound quality, such as elimination of rumbling noise and creating a feeling of linearity. Particularly engine noise, one of the major causes of interior noise, has been studied from various angles and significantly reduced in recent years. This has led in turn to increased interest in air induction noise which was a relatively minor noise source in the past. One method of reducing induction noise is the addition of several resonators to the induction system. Induction system components, including resonators, have a major effect on engine output and fuel consumption.

In the diesel field, innovative technology development has been desired for fuel injection system from the points of severe emission reduction to meet increasingly stringent emission regulation year by year respecting environmental protection and product improvement for various customer requirements including fuel consumption improvement. We have been pursuing the ideal fuel injection system which is called “ECD-U2” to meet above expectations. “ECD-U2” is the injection system of highly pressurized fuel with optimum injection timing by using of the injector controlled by high speed response magnetic valve. This system also has the fuel injection pattern controllability in one injection ( injection rate ) as one of the greatest asset. This report focuses on the new injector structure development to achieve desirable injection rate shaping for diesel engine combustion.

To improve vihicle compartment comfort, there has been a great demand for the development of odor filters which reduce odors, especially external diesel exhaust odors. Therefore, in efficiently developing cabin air filter combining dust removal and deodorant functin, a quantitative formula which enables acquisition of the correlation between sensory evaluation values and instrumental analysis values of odors has been designed and verified. We developed a deodorizing filter that effectively deodorized with minimal use of deodorant, combined with a dust filter based on these figures, to develop a high-performance air conditioning cabin air filter.

This paper deals with the current status and the future prospects in automotive electronics in Japan. Electronics systems have been individually developed for the engine, transmission, brakes, suspension, instrument panel and other areas. The next challenge will be to link these standalone systems together with interactive control blocks: for example, powertrain, vehicle control and body control. These blocks, in turn, will be coupled together by data communications links, and they will be linked through communications to data sources existing outside the automobile. Control technology will change from PID control to modern control theory and this will impact on microprocessor architecture. These control systems will increase the controllability, reliability and serviceability of the automobile as a whole.

This paper is an introduction to the design, development and heat transfer performance of a new drawn-cup plate evaporator for the refrigerant cycle of automotive air conditioning systems. This evaporator is characterized by the tank section at one side alone and U-turn refrigerant path in each tube. This system has reduced dead space and has superior overall heat transfer coefficient. Therefore, we expected that its potential performance would be much higher than any other conventional type. But, while developing it, we encountered some serious structural problems which affected the flow of the refrigerant and heat transfer in the U-turn sections. We isolated the causes of the performance degradation by analizing the refrigerant flow behavior in these sections. With this type of evaporator we finally achieved our target of 15% improved performance compared with the serpentine tube evaporator.