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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.

Recently, the quietness of the passenger compartment has become an important quality for a vehicle, and as a result, various improvements have been made to reduce the passenger compartment noise level. Particularly engine noise, a major source of interior noise, has been studied for many years and has recently been reduced to an acceptable level. As a result, air intake noise, which was a relatively minor noise source in the past, has rapidly become a noticeable noise source. This paper describes a newly developed air intake system testing apparatus, which enables us to evaluate intake noise at an early stage of engine development and also describes how the new apparatus and approach was used to develop a low-noise air intake system. This apparatus, called the PULSATION SIMULATOR, reproduces intake pulsations in the actual engine using its cylinder head and reproduces intake air flow precisely.

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.

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 purpose of this study is to present a new method for controlling a car air conditioning system, in which the air temperature can be controlled to produce any level of occupants' thermal sensation by utilizing car occupants' skin temperatures as a controlling index. In this paper, an equation for a quantitative evaluation of car occupants' thermal sensation, in steady and non-steady states, by face skin temperature and its rate of change was developed and was confirmed by experiments in an environmental chamber to be applicable for all seasons with an accuracy of ±1 in the thermal sensation voting scale we used.

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.

The smaller and lighter SV-06 sliding vane type compressor has been developed as the successor of the swash plate type 10P08 compressor for mini-car air conditioning applications. The SV-06 is the first vane type compressor in the world which utilizes an aluminum cylinder and rotor to achieve weight reduction. This was accomplished by introducing several new features to the design, such as a boron treated vane and smooth cylinder profile. Thinner vanes and a high performance oil separator were also introduced for compactness. This paper presents the many design features that allow small size and low weight while maintaining compressor performance and reliability, and focuses on the most important technology: (1) Abrasion Characteristics of Boron Treated Vane Against Al-Si Alloy (2) Oil Separator Performance

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.

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.

A new display technology is presented in order to improve the value of automotive systems which use displays; such as navigation systems and future communication systems. Displays are becoming crucial to making the systems complete and user-friendly. A full-color antiferroelectric liquid crystal display has been developed featuring excellent display image quality and wide viewing angle characteristics. The antiferroelectric liquid crystal display has a completely different operation principle from any other LCD and makes it possible to realize image quality which is comparable to TFT-LCDs with a simple matrix structure.

Recently, an increasing demand for comfort has been accelerating the trend toward multifunctional car air conditioners, including zone air conditioning which controls the cabin temperature independently for the driver and the passenger and compensates for the side solar radiation. In addition, the multifunctional air conditioner should be compact to save cabin space and ensure passenger comfort. This report describes the development of a compact and multifunctional car air conditioning unit.