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A lot of electric components have been installed in a vehicle today for comfort, safety and environment. This tendency is said to be continued in the future. Therefore, additional power supplies such as exhaust gas electricity generation system and thermal electricity generation system have been developed in the world to supply additional electricity as well as an enlargement of an alternator. However, if these new electricity supply systems are installed in a present electric power system that is controlled based on a voltage feedback, each supply system cannot be controlled effectively, because it is difficult to control output power of each system independently. An electric power based control system, Vehicle Electric power Flow management system (VEF), has been developed to avoid this problem. Sum of required electric power is calculated based on electric loads power and battery charging power. This required power is allocated to each power supply system.

Carbon brushes for automotive starters are used under severe conditions of high electric current density, high contact pressure and high sliding velocity. Therefore lead has traditionally been added to brushes to improve performance and durability. Lead is an environmental hazardous substance. In the EU, the law prohibits adding lead to brushes for electric motors which is installed on new automobiles in and after January 2005. In order to develop the lead free carbon brush for starters, we analyzed the effect and selected substitutive substance of lead. Adding lead to the brush reduces the electric resistance increase of the brush in high-temperature and high-humidity atmosphere and in high-temperature atmosphere. Furthermore lead reduces the wear amount of brush. We developed the lead free brush surpassing the lead addition brush in performance and durability by addition of lead alternatives silver and zinc.

A recent trend in the making of automotive engines, where high efficiency and low emissions need to be considered, is to mount multiple parts around the motor in order to improve overall engine efficiency. As a result of modern technology, the engine head and surrounding space have an excessive amount of parts. To accommodate the congested engine compartment, it is desirable to reduce the size of the spark plug. Small size spark plugs have the problem of poor resistance to carbon fouling and are subject to side sparks if carbon fouling occurs. This results from a reduced insulating gap between the center electrode and the housing achieved by reducing the size of the spark plug. By using visualization of flame growth and electric field strength analysis, we have conducted studies on insulator temperatures and spark behaviors in search of the optimal specifications.

Through the years, aluminum automotive heat exchangers have been developed in order to have a high performance and a light weight. Therefore, the thickness of the aluminum sheets for the application has been reduced. As the brazeability declines with the reduction in thickness, fins having a thickness under 80μm may be difficult to secure a good brazeability. Therefore, we studied the brazeability to determine the limit of thickness using clad fins from 40 to 80μm. The fillet volume formed at the joints of the fin and tube decreased with the decreasing fin thickness and the Si content in both the filler metals and the core alloys. The suitable range of Si content in the filler metals and the core alloys to obtain a good brazeability decreased with the decreasing fin thickness. When the fins were thinner than the critical values, it was impossible to have a good brazeability.

There is increasing demand for a finer atomization of fuel spray in order to improve the engine performance and mileage, reduce exhaust emissions and then improve the transient response. [1]. We are improving the shape of holes in order to enhance finer atomization. It is especially important to reveal the spray break-up process and droplet diameter quantitatively for a better development of holes shape. In this paper, we set our focus on a multiple-hole nozzle and developed a quantitative visible analysis method to investigate the spray break-up process and droplet diameter. With this method, index of the relationship between break-up process and droplet diameter was defined. And by re-shaping the holes and by arrangement of the holes, the break-up process and droplets diameter were investigated.

Increasing electric loads in a vehicle causes over-discharge of a battery and drag torque due to an alternator. This paper gives a system concept of vehicle electric power flow management to solve these issues. Its primary function includes preserving electricity in a battery, stabilizing electric bus voltage, interfacing with vehicle torque control system, and improving fuel economy. The key point to realize such a system is a unified structure. It offers ‘Plug and Play’ function for electric power management components. Newly developed Vehicle Electric Power Flow Management System (VEF ) totally controls electric power flow in a vehicle. VEF contains an Electric Power Manager and its functional sub-systems, and controls them with the key parameter ‘electric power’. The sub-system includes Generation, Storage, Conversion, and Distribution to the loads.

Up to now, while automobile electric packages have demanded the high density for small and light products, electric leaks, which have occurred due to condensation, have been a major problem. To prevent any electric leaks, a conformal coating on the electric parts (ex. ECU: Electronic Control Unit) has been needed, but in general the design rules of the conformal coating (ex. Application area) is vague. Therefore, DENSO demands to clear the design rules of conformal coating electric package for higher reliability. To meet the demand, DENSO has developed a condensation simulation method using CAE that can show the occurrence condition of condensation fast and accurately. In the result, DENSO has been able to get the design rules where to need the conformal coating in the electric package for automobiles.

In 1997, we have applied laser technology to the world's first practical adaptive cruise control (ACC) system. The ACC system is based on 2-dimensional scanning laser-radar-sensor technology that is supported by highly reliable high power diode laser. Now, we have developed 34W output power multiple-quantum-well (MQW) diode laser. The power of 870nm near IR diode laser is twice as high as conventional one, thus it meets the strong needs for robust detection of the reflective laser beams from the moving vehicle ahead. Furthermore, Au-Sn-Ni a new alloy solder has been employed to sustain high degree of vibration and thermal shock to raise reliability. The acceleration life-tests at high temperature pulsed operation demonstrate the high reliability of developed 34W high power diode laser.

Spark plugs with higher ignitability are continuously in great demand to realize high fuel efficiency and low emissions. To meet this demand, DENSO launched the Iridium Spark Plug in 1997, which realized the two characteristics that had been conventionally difficult to achieve concurrently-high ignitability and long life. The development of this product was enabled by miniaturizing the center electrode, produced using DENSO's original, highly wear-resistant iridium alloy (featuring a high melting point and excellent oxidation resistance). While spark plugs are now required to have a longer service life, they are also required to be higher in ignitability, as exhaust gas regulations have been tightened recently. However, the effort to miniaturize the center electrode is reaching a limit.

In a conventional soldering process, solvents, such as chlorofluorocarbons (CFCs), have been necessary to remove the flux-residue after soldering. A new CFC-free fluxless soldering process has been developed to obtain high sealing ability even in a small soldering area. This new process utilizes a reducing atmosphere with an appropriate load and assembly orientation to solder the parts. Under this fluxless condition, it is found that appropriate loading and good solder-wettability of the upper part increase the wettability of the lower part.

We have achieved significant weight reduction for the MS (Multi-Tank Super Slim Structure) Evaporator (1)currently in production at DENSO CORPORATION. The evaporator of HVAC unit, located in the instrument panel, is a component of the aluminum heat exchanger used in automotive air conditioners. The new evaporator uses thinner quad-layer sheet material, thanks to optimization of the electrical potential among its outer filler metal, intermediate anodic layer and core. The evaporator is thus lighter than conventional evaporators, but retains equivalent corrosion resistance.

Having a light weight, a good heat conductivity and a good brazability, aluminum alloy is widely used for automotive heat exchanger systems. The major problem with Aluminum is perforation of the tube by pitting corrosion and corrosion protection is necessary in the field. In radiator and condenser systems using the the Nocolok brazing process given good corrosion resistance using cathodic protection with sacrificial anode made of Zn-sprayed onto tube or low corrosion potential fins etc. On the other hand, in drawn-cup type evaporators, that are fabricated from brazing sheet tubes in vacuum brazing method and then covered low electro-conductive drain water film in operation, the effect of cathodic protection by the anode fin is limited to a very small area. Therefore, this has been studied to improve self-corrosion resistance of the core in the brazing sheet tube.

Fuel atomization is known as an effective means of reducing the exhaust emissions of internal combustion engines. We have focused on a multiple-hole nozzle as a cost-effective atomization method that does not require any auxiliary devices or an external energy source to carry out atomization. In this report, we will discuss the facts that 1) the primary factors of atomization with the multiple-hole nozzle lie in the flow upstream of the nozzle, and 2) the atomization characteristics such as spray droplet diameter and spray spatial distribution when the factors which effect atomization with the multiple-hole nozzle are changed. As a result, with our newly developed 12-hole nozzle injector in an actual engine, we found an HC reduction effect greater than that of a conventional air-assist injector.

The world's first continuous running, externally controlled, variable displacement compressor for automotive applications has been developed(6SE12 with DL-Pulley). This compressor design is based on a conventional swash plate internally controlled variable displacement compressor and has an integrated solenoid valve which controls displacement compressor by receiving an external electrical signal. It enables the development of a power saving system running at optimum conditions. The compressor was developed as a continuos running type by improving the component parts from a reliability standpoint. As a result, a new DL-pulley(Damping & Limiting) could be developed which has a more simple structure than conventional magnetic clutches. Therefore, the 6SE12 with DL-Pulley can reduce vehicle fuel consumption and improve the ease of installation into the engine compartment.

In applying a LAN to automotive electronics systems, an optimal protocol has been adopted for each system so far, such as body electronics system, entertainment system, service system and power train system. As low cost communication protocol “BEAN” (Body Electronics Area Network; SAE paper 970297) adopted to wider range of functions on vehicle, ECU's numbers are increased which have BEAN communication and that is branched to plural communication networks. We have succeeded in rationalization of those network systems with the gateway function on a delegated ECU for each LAN system on vehicle. And this system also realized the connection to after market products by data exchange through the gateway function, while securing vehicle fail-safe.

Recently, automotive semiconductor devices need miniaturization. One of the most important technologies is the package which encapsulates devices. In addition, the outer shape of the package is needed to change according to the mounted space. Conventional devices are mounted in the case, and encapsulated with potting resin. However this package structure is difficult to miniaturize because the case size limit. This report describes the development of the packaging technology for miniature and particular outer shape. The devices are set in the cavity and molded to one package. The three-dimension flow simulation is applied to analyze the flow in the cavity. The results of simulation correspond with experimental results. The cavity structure and the mold resin can be optimized by the simulation.

There has recently been an increasing need in various automotive monitoring and control systems for a simply structured and highly reliable high-pressure sensor to detect the higher pressures of oils, hydraulic fluids, air and air conditioning refrigerants. A simple, newly devised approach to sealing oil filled high-pressure sensors is introduced in this paper. The new structure utilizes a resin instead of the metal and glass conventionally used for hermetic sealing oil filled high-pressure sensors. This is made possible by the combined use of oils with large effective molecular diameters and carefully optimized design of shape and size of the sealing faces between sensor parts. The use of a sealed metal diaphragm allows for extensive use of the sensor with many different kinds of pressure media and in various applications.

In an effort to protect the earth's environment, emission regulations in the diesel engine field are becoming increasingly strict. One way of meeting these regulations is to atomize the fuel spray by using a fuel injection system with high-pressure injection, which activates engine combustion. With current in-line pump systems, however, it is still possible to satisfy the demand for cleaner emissions by improving the fuel spray, through measures such as reviewing high-pressure injection and initiating improvements in the nozzle. This report describes the new in-line pump system for medium duty diesel engines to meet future emission regulations. In this report, we will describe how analytical technology, such as computer simulation, was used on the pump side to make improvements for higher injection pressure.

The lateral DMOS (LDMOS) had been developed for intelligent power IC[1][2] for ECU (Electric Control Unit). The process and device simulation methodology are used while developing a devices. The physical model and parameter in analytical model are calibrated to enhance the accuracy of the simulation and to reduce lead time and costs.