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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.

The purpose of this paper is to discuss injection rate control of the nozzle for direct injection engines. This paper will focus on fuel flow analysis of the nozzle, a key component of Fuel Injection Systems (FIS). The optimum designed nozzle improves fuel flow efficiency and controls injection rate. To meet emission regulations in 1990's, FIS are required to produce higher injection pressure and injection rate control which creates better fuel spray atomization and higher utilization of air. But the higher injection pressure makes injection rate control difficult. In particular, injection rate control by needle lift traveling control is difficult because fuel flow characteristics in the nozzle change with injection pressure and needle lift. Furthermore, the forced control of needle lift results in poor fuel spray atomization.

The purpose of this paper is to discuss spray control of nozzle for heavy duty diesel engines. This paper will focus on fuel flow analysis of nozzle, key component of FIE (Fuel Injection Equipment). The optimum designed nozzle controls fuel flow and improves flow efficiency. FIE is required to produce higher injection pressure which creates better atomization and higher utilization of air. But the higher injection pressure results in increased pump driving torque, larger pump size and higher cost. To improve the fuel flow characteristic of nozzle, we analyzed it and developed a theoretical analysis method with computer model simulation to the optimum design nozzle. We also confirmed its effect by experiments.

This paper reports on research conducted at Nippondenso Co., Ltd. and Meiji University on nozzles for heavy duty diesel engines. It focuses on fuel flow analysis in the nozzle, a key component of Fuel Injection Systems (FIS). The optimum design nozzle improves fuel flow and spray characteristics. A newer and tougher emission regulation from the EPA for heavy duty diesel engines will be inevitable from 1998 onward. The goal of every company is to design new FIS in advance which meet the regulations of the future rather than paying for expensive developing costs after new laws have come into effect. To meet the regulation, requirements for FIS are higher injection pressure and injection rate control which create better fuel spray atomization and higher utilization of air. In particular, the nozzle must ensure that high injection pressure is effectively converted to fuel spray without pressure losses.

A reduction in the human arousal level can often leads to traffic or commondaily accidents. Hence, it is important to accurately detect the human arousal level. However, it is not easy to set up a method of monitoring this. The method introduced in this paper focusses on utilizing the skin potential level (SPL). The authors have developed and designed an ambulatory wristwatch type arousal level monitor based on the SPL. The monitor incorporates a new porous electrode with a dry conditioned surface, and adopts a new algorithm to detect relative changes in the SPL.

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.

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

The purpose of this study is to make clear the relationship between flow characteristics in the nozzle and injected spray characteristics. In this paper, we discuss the effect of the sac volume in the standard hole type nozzle on fuel flow and spray. The main object of this paper is to analyze fuel flow characteristics in the nozzle by using the enlarged model nozzles. Spray investigations confirmed that reducing the sac volume causes changes in the fuel injection direction at the initial stage of injection and in the spray penetration over consecutive injection. Flow investigations in the injection hole clarified that meandering the flow in the hole causes changes in the fuel injection direction. Flow investigations in the sac chamber clarified that separating the flow from the sac wall causes meandering the flow in the hole. Furthermore, the methods to restrain the flow in the sac chamber from separating from the sac wall were discussed.

In recent years, concerns with global environmental problems have become major issues. Environmental regulations such as fuel consumption/economy, for example, have become very stringent. On the other hand, the pursuit of a comfortable and spacious passenger compartment and reduced engine compartment room have become more progressive. Size and weight reduction of automotive components are necessary to cope with these requirements. With regards to the fuel filter, size reduction of the filter element is the key technology to achieve both component size and weight reduction. As to a fuel filter, the reduction of its size and weight can be accomplished by reducing the size of its element. We have studied this subject and have invented a new type of element structure. Additionally, we have developed a new filter paper which features a favorable combination of contaminant holding capacity and micron rating.

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.

In recent years, diesel engine exhaust gas regulations become more severe due to environmental concerns. Especially, particulate reduction is one of the biggest concern, and the reduction through high injection pressure has been studied.(1), (2) and (3) However, much is not yet known about the influence of changes in fuel flow inside the nozzle tip on atomization and engine performance, and there would exist a lot of room for exhaust gas reduction through the nozzle modification. In this research we found that changing the shape of the nozzle tip showed a remarkable difference in the smoke emission at low engine speed, analysis showed that difference in the flow rate at the nozzle orifice cause difference in the fuel spray droplet size and therefore the difference in the smoke emission.

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 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.

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.

This paper describes the development of the two-dimensional semiconductor device simulator called DS2* and its application in automotive power MOSFET design. DS2 clarifies carrier motions in MOSFETs under various operating conditions and calculates the current characteristics in intense electric fields in order to evaluate the device breakdown. Simulation results with p channel power MOSFETs for automotive application indicate that on resistance is significantly dependent on device miniaturization and that device breakdown is caused by one of three mechanisms which are, avalanche from the surface layer, reach through arid punch through.

This paper presents a new method of numerical analysis of 2-dimensionnl incompressible flow which is useful for a stage of product design, developed on the basis of both FEM and FDM, and also a new model of vorticity shedding has been developed. A computer simulation program was employed to confirm the following features of the present method. 1) The flexibility of any object shape by FEM. 2) The stability of the calculation by the modified FLIC* method (FDM). 3) The approximation of the flow separation on the boundary by the vorticity generating model. After applying the program to the design of the two types of air flow meters; i.e., the vane and Karman types, it has been found that the program is practically useful to obtain the optimum design of air flow meters.

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.

Considerations have been made on using turbine pumps as in-tank fuel pumps for electronic fuel injection systems (EFI). Flow channel dimension values, which had not been previously used for these types of pumps, were found to be very suitable for use as a fuel pump. The oil film visualization method was used to observe the flow pattern within the pump, and the results served to improve the flow channel shape. This contributed to designing a compact and efficient high-pressure fuel pump.

Performance optimization of small diesel engines is greatly owing to the matched improvements between combustion chamber and fuel injection system. Fuel injection characteristics are especially important to realize optimum engine performance in all speed range. In recent years, lower noise and white smoke reduction during cold temperature operation have been strongly required for agricultural and industrial application, which are the same technical trend as automotive's. As these two requirements are in the trade - off relationship from a combustive point of view, it is very complicated to realize both at the same time. Therefore, fuel injection characteristics are analyzed in detail for important factors such as injection pressure pattern, its behavior and injection timing so that the aimed optimum engine performance is obtained. This paper describes an optimization example of achieving simultaneous reduction of white smoke and noise by fuel injection characteristics' improvements.