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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.

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 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.

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.

In resent years,lower noise has been in high demand in small diesel engines for agricultural and industrial uses as well as automotive engines. Furthermore,emission regulations becomes more severer due to environmental concerns. In order to satisfy these objects,diesel engine combustion needs to be improved. Especially fuel injection system is the key element to control engine combustion and should be improved dramatically. This research is to pursue the ideal fuel injection system to realize optimized diesel engine combustion which creates low combustion noise and clean exhaust emission. Recent progress will be reported in fuel injection technology including injection pressure pattern, injection rate pattern, injection timing and spray pattern, etc.

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.

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.

It is well known that pilot injection is an effective method of reducing diesel knock noise during idling, but no actual system has as yet been commercially produced. With the objective of developing a practicable pilot injection device, simulations were conducted of various simple mechanisms in order to determine the best specifications and analyze the fuel injection characteristics. Based on these results, a chamber expansion type pilot injection device, which enables the injection pump pressure chamber volume to be increased at a given moment during the fuel compression stroke, has been developed and has been found to remarkably decrease knock noise during cold idling. An investigation into the effects of this device on output power, exhaust emissions, cold startability and durability revealed that it is eminently suitable for practical application.