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The electric power steering (EPS) is increasing its number since there are many advantages compared to hydraulic power steering. The EPS saves fuel and eliminates hydraulic fluid. Also, it is more suitable to the cooperation control with the other vehicle components. The EPS is now expanding to the heavier vehicle with the advance in the power electronics. In order to meet customer's needs, such as down-sizing, lower failure rate and lower price, we have developed the new motor control unit (MCU) for the EPS. The motor and the electric control unit (ECU) were integrated for the better installation. We adopted new technologies of redundant 2-drive design for more safe EPS. “2-drive Motor Control technology” which consists of dual winding, two torque sensors and two inverter drive units. In our developed MCU, even if there is a failure in one of the drive unit, the assistance of the EPS can be maintained with the other drive unit.

In a diesel engine, the mixing of the fuel spray and in-cylinder air controls rate of beat release during combustion, namely it will determine the thermal efficiency, maximum output and gas or noise emission, etc. Therefore, it is important to measure the droplet size and its volume density distribution in diesel fuel sprays. The optical measuring method, which includes a light scattering and holographic technique, seems the only feasible method for analysing these unsteady characteristics of fuel sprays. The light scattering technique described herein was based upon Mie scattering theory, and the droplet size and volume density distribution of fuel sprays were calculated from the combination of the light extinction and the forward-to-backscattering ratio of Mie scattering intensity. The volume density and droplet size distribution of fuel sprays were obtained from the light intensity distribution on a photograph of fuel sprays.

When the power or specific fuel consumption is estimated in design process, thermodynamic consideration for the estimation is generally insufficient. Hence, a theory that can estimate these performances accurately is investigated in this paper. As a result of investigation, it is clear that the effect of pumping loss in wide-opene throttle valve operation has to be excluded from the mechanical loss which is measured in the motoring test. It also becomes clear that a new coefficient called pumping loss coefficient ηP has to be considered for the negative work for pumping. From the foregoing, theoretical formulas for estimating the net power Pe and net specific fuel consumption be. which are formed with various efficiencies and coefficients are as follows: It is verified that the estimation from these formulas agree well with the experimental test values using stoichiometric mixture ratio.

Described here is the tuning of the combustion systems of a precombustion chamber diesel engine for lower level of exhaust gas emission. The key points of the tuning are the decrease of the prechamber volume, the selection of the combustion chamber configuration, the injection nozzle characteristics and the optimum injection timing. It was made clear, in the results of investigation, that the degradation of lubricating oil and the cavitation pitting on the outer wall of cylinder liner were directly concerned with the combustion characteristics of low emission systems. And both problems have been solved. The result of combustion tuning of the engine shows less than 5 g/hp-h of NOx + HC with CARB 13 mode test cycle without deterioration of performance nor durability.

Described herein is the tuning of the combustion system of a direct injection type diesel engine to obtain low emission level and better fuel economy. Though the most important method of emission control for a direct injection system is considered to be timing retardation, it brings a higher level of smoke density and fuel consumption. In order to remove these faults, the authors developed a new combustion system based on a newly designed intake port which provides a favorable local mixing of fuel droplets and air in the combustion chamber for ignition by means of air turbulence. This new combustion system was analyzed with high speed photographs which were taken from the underside of the piston to enable observing the whole combustion chamber. Favorable characteristics of ignition and burning pattern of the new system were recognized by this analysis.

A new concept for diesel combustion was investigated by means of numerical simulation, engine experiment, and combustion observation in order to realize a simultaneous reduction of NOx and particulate emission. This concept (HiMICS: Homogeneous charge intelligent Multiple Injection Combustion System) is based on pre-mixed compression ignition combustion combined with multiple injection. Combustion characteristics of HiMICS concept was investigated by comparing with both a standard single injection and a pilot injection. In HiMICS concept, the pre-mixture is formed by a preliminary injection performed during a period from the early stage of the induction stroke to the middle stage of the compression stroke. Modified KIVA-II code was used to predict engine performances and emissions of each injection method. The simulation results show a capability of considerable improvement in the trade-off relation between NOx emissions and fuel consumption of HiMICS.

Radio noise generated by the ignition system of internal combustion engines is primarily caused by the capacitive discharge current flowing in the ignition circuit when the spark occurs at spark gap. It is known that suppression of the capacitive discharge current usually effective in reducing the radiated ignition noise level. [1]* However, with exposed engines such as outboard marine, motorcycles, and particularly, in devices with long metal bodies, the radiated level peaks at a frequency which is determined by the length of the metal body. The authors found that the phenomenon described above could be explained by assuming electrostatic induction current. This was based on the noise voltage from the ignition system to the device. This paper intends to report the findings of this research.

This paper represents the adaptation of turbo charger to single cylinder 450cc SI engine which is used for the student formula competition. The experiment and 1D engine simulation called as GT-Power were performed to confirm the effect of valve profile, compression ratio and air fuel ratio on the engine performance under the naturally aspirated condition. The maximum valve lift of the intake valves increased 27% and that of the exhaust valves increased 15% as compared with the low profile cam. The compression ratio was increased from 12.3 to 13.5 by changing the piston top land length in order to improve the thermal efficiency. It was confirmed that the torque peak was moved from 6000 rpm to 8000 rpm by changing the valve profile. Furthermore, turbo charger was adapted to the engine as changing the capacity of the turbocharger, the maximum boost pressure and the air fuel ratio.

Nowadays, cornering performance of FSAE (Formula SAE) cars are dramatically improved due to less mass, kinematic developments and tires. In such circumstance, under high speed conditions, aerodynamical devices work better. It had been decided to attach aerodynamical devices that consist of front wing, rear wing, diffuser (floor) and deflector for SR11 (Fig. 1, Table 1), a FSAE car developed by Sophia Racing (Japan). Fig. 1 SR11 Table 1Vehicle configuration of SR11 To start with developing aerodynamical devices, it had been assumed that how they work. Lap time simulation had been done with VI-car-realtime, which shows the laptime could be shorten by 2 seconds of 60 seconds for a usual FSAE endurance course with 60kgf at 60km/h downforce. Dragforce had been assumed to work well while once, it had been supposed to have a bad influence for laptime.

1 Many environmental problems, such as global warming, drain of fuel and so on, are apprehended in all over the world today, and down-sizing is one of the wise ways to deal with these problems. It is significant that a decrease of the engine power must not be produced by using a small displacement engine, so more efficient engine system should be designed to increase the torque with a little fuel. This study achieves an improvement of efficiency for mounting the super charging system on the small displacement engine. As a result, comparing a super charged engine and a naturally aspirated one to drive the same course and laps, fuel consumptions are 2547 [cc] and 3880 [cc], respectively, and an improvement of fuel consumption is 52%. Designing points to mount super charging system is introduced below. 1 It can be forecasted that intake air blow-by gas at the combustion chamber is increased in low engine speed because engine for motor cycle is used.

A current unmodified and modified engines with different amounts of thermal insulation have been used to generate data from which changes in bsfc, cooling loss, emissions, exhaust loss were determined. Since legislative requirement exists for allowable emission of NOx, fuel injection timing and other controllable factors were adjusted to maintain constant NOx emission except a test of influence on NOx emission according to the rate of heat insulation (adiabaticity). The effect of higher combustion temperature on the combustion phenomena is discussed.

The experiments were done in order to obtain the fundamental information that would be needed to build a physical model which expresses the heat transfer phenomena in the intake port model and manifold. In the experiments, the heating conditions and the period of the cyclic change of the gas velocity were changed as experimental parameters. In addition to those parameters, the Strouhal number was applied to express oscillating flow. As a result, the heat transfer in the experiments became clear, and the equations were obtained to show the Nusselt number using the Reynolds number, the Graetz number and the Strouhal number.

Cu-Pb alloy bearings were collected from diesel engines actually operated in the United States and Japan, and a study was made of the damage to bearing overlays and linings. Results indicated exposure of compound layers produced by the diffusion of overlay components due to the complete removal of overlay from large segments of the bearing inner surface. There were many bearings in which the Pb had been last from the Cu-Pb alloy. Based on the above results, experiments were conducted in which a tester was used to recreate the damage conditions of the overlay and the lining. Then, based on observation and the results of regenerative tests, it was concluded that high temperatures and lubricating oil used over a long period had a great impact on damage.

In this paper we propose a new multi-functional steering wheel switch for HVAC and audio systems. This new switch has five buttons on the front side of the spoke area and one button with vibration on the backside of it. Drivers can operate either HVAC or audio functions with the front switches, and HVAC or audio mode can be alternatively selected by pressing the back switch. Since different vibration modes are assigned for the HVAC and audio mode, drivers can also easily recognize which function can be operated. By changing the assignment of the mode in this way, the switch can operate more than 10 functions with 6 buttons allocated on the spoke area. Several kinds of evaluations were performed in order to develop this multi-functional switch. At first, to optimize the positions of the buttons, the behaviors of thumbs and fingers were measured. Also the physical workload of the thumb motion and middle fingers' postures was evaluated when subjects operated the switches.

Historically the high speed diesel engine for commercial vehicles has been developed along with its combustion system in compliance with political and economical changes. After the 1970's, stricter exhaust emission regulations and fuel economy requirements induced combustion developments and application of turbocharged and inter cooled engines. From the late 1980's, high pressure fuel injection has been investigated and recognized as an essential tool for lowering emissions especially of particulate matter. Although turbulence effects on both in-cylinder air motion and during the combustion process are quite effective, they show different phenomena in conventional and advanced high pressure fuel injection systems. In the 1990's, multiple injection with high pressure has been attempted for further reduction of NOx and particulate matter.

A historical review of Japanese turbocharged diesel engines for heavy duty vehicles is described, and newly developed turbocharged diesel engines of HINO are introduced. The design features of these engines include new turbocharging technologies such as highly backward curved impeller for compressor blade, variable controlled inertia charging and waste gate. Laboratory and field test results demonstrated better fuel economy and improved low speed and transient torque characteristics than the predecessors. Several operational experiences, technical analysis and reliability problems are discussed.

This paper presents technical solutions and a development process to accomplish not only superior fuel economy but also excellent driveability with a turbocharged diesel engine for heavy duty trucks. For better fuel economy, one of the basic considerations is how to decrease the friction losses of the engine itself while keeping the required horsepower and torque characteristics. A high boost turbocharged small engine offers this possibility, but it has serious disadvantages such as inferior low speed torque, poorer accelerating response, insufficient engine braking performance, and finally not always so good fuel consumption in the engine operating range away from the matching point between engine and turbocharger. These are not acceptable in complicated traffic conditions like those in Japan - a mixture of mountainous and hilly roads, city road with numerous traffic signals, and freeways.

We have developed a rear spoiler with built-in antenna. The spoiler has two features. First, the built-in antenna does not protrude from the vehicle contour and has an improved serviceability. Second, the air flow effect provides the driver with a clearer rear view, resulting in an improved safety. This paper discusses characteristics of the rear spoiler with built-in antenna.

In motorcycle market, there is demand for technology that makes it possible to drive fast safely. One such technology has already been commercialized; control that prevents front lift while enabling maximum acceleration performance. We have developed a more accurate version of this control. In order to maximize acceleration performance, it is necessary to keep front lift angle as close to zero as possible. Reducing output driving force helps to keep the front lift angle low, but if output driving force is reduced too much, it will degrade acceleration performance. Feedback control that reduces output driving force when front lift is detected is effective for optimizing this trade off, but increasing feedback gain too much to reduce front lift angle will cause output driving force to change suddenly, making for a less comfortable ride.

Attribute to high heat transfer rate and less complexity, the Helical coil sub-cooled condenser (HCSCC) can provide the most innovative and unique application for the air conditioning system. In the case of automobiles, reduction in air-conditioning load may diminish the vehicular emission, and power consumption as the air-conditioning load is the most power-consuming components after the engine load. Moreover, to solve the problem, we focus on the helical type heat exchanger. It may play a vital role in reducing the weight and increase the performance of the small engine because of the compact structure and lighter weight. The compressor unit is the most vital component of the refrigeration cycle, but the condenser unit is also one of the most critical devices, and the author tried to reduce the power consumption by enhancing the performance of the condenser.