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Engine torque profile shaping strategies have been proposed to reduce noise & vibration for passenger cars. However, it has not been sufficiently studied that feasible torque profile for vibration suppression is dependent on engine speed and target torque shape. On the other hand, combustion pressure profile shaping strategies have been proposed to reduce noise. However, there is almost no research of the quantitative evaluation of contribution of combustion pressure profile. First, the torque profile shaping was studied. Pre-compensated torque and 2-step torque were selected as typical target torque profiles. An effectiveness of vibration suppression by two torque profiles was evaluated by both drivetrain vibration model and engine torque profile model which have been established well. As a result of studying the torque profile shaping, timing of torque rise by the 2-step torque generation is delayed or advanced.

Fuel design concept has been proposed for low emission and combustion control in engine systems. In this concept, the multicomponent fuels, which are mixed with a high volatility fuel (gasoline or gaseous fuel components) and a low volatility fuel (gas oil or fuel oil components), are used for artificial control of fuel properties. In addition, these multicomponent fuels can easily lead to flash boiling which promote atomization and vaporization in the spray process. In order to understand atomization and vaporization process of multicomponent fuels in detail, the model for flash boiling spray of multicomponent fuel have been constructed and implemented into KIVA3V rel.2. This model considers the detailed physical properties and evaporation process of multicomponent fuel and the bubble nucleation, growth and disruption in a nozzle orifice and injected fuel droplets.

In this paper, emissions reduction technologies applied to high-speed direct injection (HSDI) diesel passenger car engines to meet the stricter exhaust emission legislation are described. To reduce smoke, the F.I.E. has been improved by using a radial-piston distributor pump which delivers fuel-injection-pressure up to 120MPa. Cooled exhaust gas re-circulation (EGR) system and increase in volume ratio of the combustion chamber has made it possible to increase EGR ratio and reduced nitrogen oxides (NOx) and smoke simultaneously. Furthermore, improvements in the oxidation catalyst activating temperature reduces PM at lower exhaust gas temperatures. As a result of applying these technologies, a clean and economical HSDI diesel engine for passenger cars, which complies with Japanese '98 exhaust emissions legislation and has better fuel economy than indirect injection (IDI) diesel engines (above 15%), has been developed.

A new state of the art DOC (Diesel Oxidation Catalyst) having superior light-off and exothermic activity for forced regeneration compared to conventional Pt base passive DOC, was investigated for LDD application. The DOC uses the latest Pt/Pd technology resulting cost effective DPF system. The newly developed DOC demonstrated improved catalytic activities from Pt only DOC in model gas or engine bench tests. In this study, DOC at early development stage showed excellent light-off activity in model gas and engine bench test compared to conventional Pt only DOC, however, it showed “extinction” phenomenon which is one of the deactivation mode while the post injection and it was observed when post injection operation was done at lower DOC inlet temperatures, e.g. below 250 C. Temperature profiles along diameter and length into DOC bed while active regeneration suggested extinction would be caused by fouling of supplied hydrocarbons derived from diesel fuel.

To apply a fuel economy performance to AT&CVT fluid for common use (hereinafter AT/CVT fluid) and manual transmission fluid, by optimizing fluid viscosity, a fundamental study was investigated. Generally, it is well known that the viscosity of polymer-added transmission fluids is gradually reduced, due to deterioration of the viscosity index improver caused by shear stress. An excessive viscosity reduction causes an operation failure or damage to the transmission. Considering above factor, the authors focused attention on the potential of a low viscosity formulation to improve fuel efficiency by reducing an internal stirring-resistance of the transmission. Also from the viewpoint of friction characteristics, the performance of a base oil was studied. Utilizing the EHL (Elast-Hydrodynamic Lubrication) tester [1] and vehicle tests, the performance of base oils was evaluated for the fluid development.

As part of the International Lubricant Standardization and Approval Committee's (ILSAC) goal of developing a global automatic transmission fluid (ATF) specification, members have been evaluating test methods that are currently used by various automotive manufacturers for qualifying ATF for use in their respective transmissions. This report deals with comparing test methods used for determining torque capacity in friction systems (shifting clutches). Three test methods were compared, the Plate Friction Test from the General Motors DEXRON®-III Specification, the Friction Durability Test from the Ford MERCON® Specification, and the Japanese Automotive Manufacturers Association Friction Test - JASO Method 348-95. Eight different fluids were evaluated. Friction parameters used in the comparison were breakaway friction, dynamic friction torque at midpoint and the end of engagement, and the ratio of end torque to midpoint torque.

For fuel economy improvement by lean-burn gasoline engines, extension of their lean operation range to higher loads is desirable as more fuel is consumed during acceleration. Urgently needed therefore is development of emission control systems having as high NOx conversion efficiency as three-way catalysts (TWC) even with more frequent lean operation. The authors conducted a study using catalysts loaded with potassium (K) as the only NOx trapping agent in an emission control system of a lean-burn gasoline engine.

The purpose of this study is to explain the characteristics of homogeneous charge compression ignition. n-Heptane, which has the same cetane number as diesel fuel, was chosen for the fuel. A rapid compression machine was used to clarify the effects of air-fuel ratio, O2 concentration, and compression temperature on ignition delay and NOx emission. These investigations allowed the introduction of a formula for ignition delay.

To reduce the idling rattle of manual transmissions, the computer simulation has been utilized. However, the conventional simulation model could not express properly the relationship between the transmission oil temperature and the rattle noise level, especially in case of transmission with backlash eliminator in constant mesh gears. In this study, the authors carried out detail experiments investigating the motion of each part in the transmission. Based on the experimental results, an additional mass representing all constant mesh speed gears supported on plain or rolling element bearings was introduced to the simulation model. Using the improved model, it was confirmed that the calculated RMS value of the fluctuation in countershaft angular acceleration corresponds to the experimental rattle noise level.

With society demanding automobiles that provide higher fuel efficiency, safety of occupants in collisions and that at the end of their service life can be recycled with low environmental impact, the steel industry is tackling the needs of the automobile industry by developing ever-higher performance steel materials and simulation technologies that can demonstrate the performance of steel materials at the development stage without the need for costly prototype testing. In this paper, weight reduction of automobile body in Japan will be discussed. The main items will be as follows: (1) Development of Automobile Steel Sheets, (2) Materials for Automobile Bodies, (3) Materials and Technologies (Tailored Blanks, Hydroforming and Locally Quenching) for Reducing the Weight of Panels and Reinforcing members, (4) Future Prospects.

The International Lubricant Standardization and Approval Committee (ILSAC) ATF subcommittee members have compared the two oxidation bench test methods, Aluminum Beaker Oxidation Test (ABOT) and Indiana Stirring Oxidation Stability Test (ISOT), using a number of factory-fill and service-fill ATFs obtained in Japan and in the US. In many cases, the ATFs were more severely oxidized after the ABOT procedure than after the same duration of the ISOT procedure. The relative severity of these two tests was influenced by the composition of the ATFs. The bench test oxidation data were compared with the transmission and the vehicle oxidation test data.

A resin cylinder head model was produced using a rapid prototype producing system. The resin model was used in the lost-wax casting process instead of a wax model. The casting molded by this method was as precise in both shape and dimensions as a casting produced using a metal mold. This paper describes the manufacturing process of cylinder head material using this method in detail.

A method of fatigue life prediction of spot welded joint under multi-axial loads has been developed by fatigue life estimation working groups in the committee on fatigue strength and structural reliability of JSAE. This method is based on the concept of nominal structural stress ( σ ns) proposed by Radaj and Rupp, and improved so that D value is not involved in stress calculation. The result of fatigue life estimation of actual vehicle with nominal structural stress which was calculated through newly developed method had very good correlation with the result of multi-axial loads fatigue test carried out with test piece including high strength steel.

New 440MPa class high-strength steel, which had high r-value(1.6) and elongation(38%), was applied to outer-panel for the first time in the world. In this development FEM simulation was carried out to clarify the necessary steel properties, and the production conditions in strip mill were established. 10-kg weight reduction was realized by using this steel.

In this paper the fatigue life of welded steel sheet structures is predicted by using FE-Fatigue, which is one of fatigue analysis software tools on the market, and these predicted results are evaluated by reference to corresponding experimental results. Also, we try to predict these structures by using two fatigue life prediction theories established by the JSAE fatigue and reliability committee to compare prediction results. It was confirmed that spot welds fatigue life predictions agree qualitatively with corresponding experimental results and arc welds fatigue life predictions are in good agreement with corresponding experimental results in cases where the SN curve database is modified appropriately.

In order to examine the compatibility of improvement of crashworthiness with weight saving of automobiles by using high strength steel, a combination analysis of Finite Element Method and Dynamic Mechanical Properties has been established. Material properties used in this analysis have been measured by “one bar method” high velocity tensile tests, which can examine the deformation behavior of materials at a bend crush speed range (∼55km/h). It was confirmed that the strength of steel measured by one bar method was raised remarkably after press and hydro forming of high strength steels. It was also confirmed by FEM analysis and load drop test that absorbed energy of bend crush was improved by pre-strain effect. Further, we proved that absorbed energy of bend crush was also improved by appropriate design of thickness and the ratio of bend span and plate length. These effects are applicable to respective high strength steels.

The influence of tensile strength on fatigue strength and the effect of strengthening mechanism on fatigue notch factor were investigated into conventional mild steels, HSLA steels, DP steels and TRIP steels. The grade of studied steels was altered from 440MPa to 780MPa. Not only smooth fatigue specimens with side surface ground and smooth fatigue specimens with laser-cut side surface but also fatigue specimens with a pierced hole were prepared for each of steel sheets. Fatigue tests were conducted in an axial load method. These experiments made it clear that the fatigue limits of smooth specimen increase along the tensile strength approximately independent of strengthening mechanism but those of notched specimen do not necessarily increase along the tensile strength. Namely, fatigue limits of DP steels and TRIP steels with notch increase in proportion to tensile strength although those of HSLA steels with notch do not increase.

The new improved energy conversion efficiency has been requested instead of the traditional theoretical thermal efficiency [ηth] [1]. For the efficiency in a combustion chamber, three new ideas have been adopted [2] [3]; (1) the basic available energy (quantity), (2) the total energy supplied instead of heat supplied and (3) the energy flow including energy for compression work in a whole engine. The new energy conversion efficiency is termed “the [A-base] energy (conversion) efficiency [ηENd]”. And more, the provisional-net wok as the fourth new idea [2] [3] is adopted that is the difference between theoretical work and energy for compression work for a next cycle. And, “the provisional-net energy conversion efficiency (d) [ηPNd]” [2] [3] is newly taken up from it.

For compliance with stringent exhaust emissions regulation, a lot of the world's Heavy Duty Diesel Engines (HDDE) have been recently equipped with electronically controlled components, such as the Fuel Injection Equipment (FIE), Exhaust Gas Recirculation (EGR) system, Variable Geometry Turbocharger (VG). Flexibility of engine control has been increasing more and more with electronic control for low exhaust emissions and good performance. However, determination of the optimum combination of engine control parameters is extremely tedious, because an engine has so many parameters to be optimized and their interactions are complicated. Therefore, a Design of Experiments (DOE) method was used to optimize the engine control parameters, which effect emissions and performance, in a shorter time. After using this method, it was recognized that it was an effective method to optimize various engine parameters, and was very convenient for engine development.

In the previous paper(1), the authors reported the calculation method they developed for predicting the idling rattle in manual transmissions. This method provides data that represent noise levels to which human ear is not sensitive by numerical values. In the study described in this paper, the authors attempted to produce audible noise through a speaker by the following process: create time-series data of fluctuation in the angular acceleration obtained by the calculation (which is considered to correspond to rattle noise); create next-stage data by applying convolution of a transmission case's vibration transfer characteristics filter obtained by the experiment to the above-mentioned time-series data; convert the filtered data into a wave file; and then input the file to a personal computer to obtain audible sound as output. The audible noise thus produced provides a means of evaluating the level and nature of noise in the way humans naturally experience it.