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Technical Paper

Air Conditioning System for Electric Vehicle

The electricity stored in the battery is the only source of energy driving an electric vehicle (EV). Therefore, the target of the air conditioning system for EVs is to cool and heat the air in the cabin and demist the wind shield using a small power consumption. We have developed a dehumidifying heat pump system that consists of an interior unit constructed to separate the recirculation air flow and fresh air flow, an exterior unit capable of controlling the absorption and radiation of heat, and an inverter-controlled, electric-driven compressor. The results of an experiment using this system proved that it could provide comfortable cabin air and good visibility through the wind shield with small power consumption at ambient temperatures ranging from -10°C to 40°C.
Technical Paper

Benefits of New Fuel Injection System Technology on Cold Startability of Diesel Engines - Improvement of Cold Startability and White Smoke Reduction by Means of Multi Injection with Common Rail Fuel System (ECD-U2)

In the diesel engine field, increasingly strict emission regulations and customer requirements have necessitated advanced technology. One important subject for diesel engines is cold startability and white smoke under cold conditions. In this paper, the combustion mechanism of a multi cylinder engine under cold conditions is discussed. First, during a starting condition, it is proved that the cold flame, which is caused by previously misfired fuel during intermittent combustion, promotes good combustion on the following cycle. Secondly, following engine starting, it is estimated that there is minimum fuel quantity above which combustion is carried out. The minimum fuel quantity depends upon the temperature of the combustion chamber. Unbalance between the minimum fuel quantity and actual injection quantity results in white smoke emission.
Technical Paper

Air Purification and Fragrance Control

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.
Technical Paper

Development of Hologram Head-Up Display

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)
Technical Paper

Acoustic Noise Reduction in Automobile Alternator by Constrained Layer Damping of the Stator

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.
Technical Paper

A Low-Speed In-Vehicle Network for Body Electronics

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.
Technical Paper

High Speed Control of Damping Force Using Piezoelectric Elements

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.
Technical Paper

Ferroelectric Ceramic Materials to Protect Automotive Electronic Devices from Electromagnetic interference

EMI suppresion capacitors and filters are common in automobile electronics today, but they are insufficient for heavy concentrations of wideband electromagnetic radiation. To resolve this problem, a highly-integrated Ceramic Absorber was developed to efficiently shield against frequencies from 1MHz to 1000MHz, which is mountable on the control circuit board easily, as it is the form of a flat plate strip line. This filter provides the signal line with an electromagnetic absorption effect through line transmission characteristics. Research into ceramic materials was required to determine the specific dielectric constants and frequency characteristics of ferroelectric ceramic materials. The development objective was material with optimum dielectric dispersion, as determined from research into energy absorption based on the Debye dielectric dispersion theory.
Technical Paper

Electronic Transmission Control

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.
Technical Paper

High Speed Automated Manufacturing System for Automotive Compact Relay

The conventional relay manufacturing line required several workers for manual assembly and adjustment operations. This problem was compounded by the fact that high precision quality of the product could not be easily achieved. To solve these problems, Nippondenso has made a breakthrough in developing new technologies which were incorporated in an automated relay manufacturing line, enabling an individual process cycle time of 0.9 seconds throughout all manufacturing processes. This includes component parts fabrication, assembly, inspection, adjustment and packaging, and does not require the direct intervention of any operators. Various models of relays can be run at the same time in this line because the set up time for different models is almost zero. This greatly improves production control.
Technical Paper

Automotive Electronics in Japan - The Next Five Years

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.
Technical Paper

Size and Weight Reductions in Charging and Starting System Components

Since 1970, Toyota Motor Corporation has achieved a total weight reduction of 34% in its overall charging and starting systems. This has been done in a variety of ways: the alternator, starter and battery, the major components of the systems, have been designed for optimal efficiency according to Computer Aided Engineering (CAE) principles; new machining technology has been developed for these components, and new lightweight raw materials have been used in their construction. In addition to these measures, the charging and starting units have been conceived as families so that their sizes could be reduced and significant reductions in weight achieved.