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To reduce the Body in White (BIW) mass, it is necessary to expand the application of Advanced High-Strength Steels (AHSS) to complex shaped parts. In order to apply AHSS to complex shaped parts with thinner gauge, high formability steel is required. However, higher strength steels tend to display lower elongations, compared with low/medium strength steels. Current AHSS are applied to limited parts for this reason. The new 1.2GPa material, with high formability, was developed to solve this issue. The mechanical property targets for the high elongation 1.2GPa material were achieved by precise metallurgical optimization. Many material aspects were studied, such as formability, weldabilty, impact strength, and delayed fracture. As the result of this development, 1.2GPa AHSS has been applied to a new vehicle launched in 2013.The application of this material was the 1st in the world, and achieved a 11kg mass reduction.

Gas chromatographic methods for analyzing hydrocarbon species in vehicle exhaust emissions were compared in terms of their collection efficiency, detection limit, repeatability and number of species detected using cylinder gas and tailpipe emission samples. The main methods compared were a Tenax cold trap injection (TCT) method (C5-C12 HCs) and a cold trap injection (CTI) method (C2-C4 HCs; C5-C12 HCs). Our own direct (DIR) method was used to confirm the collection efficiencies. Both methods yielded good results, but the CTI method showed low collection efficiency for some C2-C4 HCs. Measurement of individual species is needed with this method for accurate analysis of tailpipe emissions. Both the CTI method and the TCT method combined with the DIR method for determining C2-C4 HCs yielded nearly the same ozone specific reactivity values for the NMHC species analyzed.

Variable flux permanent magnet synchronous machines (VFPMSMs) have been designed by using finite element analysis (FEA) to evaluate speed-torque capability considering requirement for magnetization state (MS) manipulation. However, due to its unique characteristic to change the MS, numerous combinations of design parameters need to be evaluated to achieve a final design. To accelerate the design process, this paper presents a method that consists of an equivalent magnetic circuit model and a process to obtain magnet width and thickness that satisfy target maximum torque and power factor (P.F.) capability. This model includes magnet operating point analysis under given magnet width and thickness condition to achieve target MS and avoid demagnetization at full load. This analysis provides desired stator magnetomotive force, magnet and stator induced flux linkage. Therefore, expected torque and P.F. capability is calculated.

Sophisticated product designs enrich people's lives and social demands for creation of good designs are quite strong. In the automobile industry, good design quality is one of the principal factors for determining market competitiveness. In this situation where good design quality is required of every product, the authors have developed a CAD/CAM system which makes it possible to create good and accurate designs by translating designers' ideas directly and quickly into high quality CAD models, a capability that has long been desired. With this high performance system, freely formed curves and surfaces can be easily manipulated with a man-machine interface familiar to industrial designers accutomed to the conventional design process. The system also integrates photo-realistic rendering, stereography and NC milling machines for verifying differences between the realized shape and the image in the designer's mind.

The object of this study is to present a newly developed optimization method for car body design. In the case of designing car body without roof, lowering of the bending and torsional rigidities which lead to a lowering of resonant frequencies should be considered. In order to overcome these problems, a new optimization method has been developed and applied successfully. This method is based on the pseudo least square method and all the sheet elements in the finite element method are treated as design variables.

Gasoline engines employ various mechanisms for improvement of fuel consumption and reduction of exhaust emissions to deal with environmental problems. Direct fuel injection is one such technology. This paper presents a new quasi-dimensional combustion model applicable to direct injection gasoline engine. The Model consists of author's original in-cylinder turbulence and mixture homogeneity sub model suitable for direct fuel injection conditions. Model validation results exhibit good agreement with experimental and 3D CFD data at steady state and transient operating conditions.

It has been found that over Rh/a specified support NOx is eliminated using rich/lean excursions in a different reaction mechanism from a Lean NOx Trap system, where NO is decomposed into nitrogen and oxygen. The contribution of the transient NOx direct decomposition to NOx elimination depends on both reaction conditions and supports. 0.1-0.5wt%Rh and 0.5wt%Pd/a specified support: X can mainly catalyze the transient NO decomposition. On the other hand, on another Rh-based catalyst NO reduction proceeds mainly in the Lean NOx trap system. As expected from the NO elimination mechanism, the newly developed catalyst has shown a high tolerance against SOx.

A robotic driver has been designed on the basis of an analysis of a human driver's action in following a given driving schedule. The self-learning algorithm enables the robot to learn the vehicle characteristics without human intervention. Based on learned relationships, the robotic driver can determine an appropriate accelerator position and execute other operations through sophisticated calculations using the future scheduled vehicle speed and vehicle characteristics data. Compensation is also provided to minimize vehicle speed error. The robotic driver can reproduce the same types of exhaust emission and fuel economy data obtained with human drivers with good repeatability. It doesn't require long preparation time. Thereby making it possible to reduce experimentation work in the vehicle development process while providing good accuracy and reliability.

This paper describes a simple engine model at idling and it applies particularly to idle speed control. Through linearization in the neighborhood of the nominal operating points (650 rpm), the engine is expressed as a reduced-order constant coefficient state variable (2 state) model. It was produced through the system order-reduction method. The strategy for controlling idle speed uses the Linear Quadratic and Integral (LQI) optimal control theory. The tracking controller was designed using a state variable engine model, and the performance index was minimized. Since state variables are artificially introduced, they are not directly accessible. Therefore, they must be estimated in accordance with a stored dynamic model (i.e. observer), in which the engine dynamic behavior is estimated on the basis of a state variable model which represents the engine's internal states, in determining controlling values.

Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio is an example of a technology for improving the thermal efficiency of gasoline engines. A significant issue of a high compression ratio engine for improving fuel economy and low-end torque is prevention of knocking under a low engine speed. Knocking is caused by autoignition of the air-fuel mixture in the cylinder and seems to be largely affected by heat transfer from the intake port and combustion chamber walls. In this study, the influence of heat transfer from the walls of each part was analyzed by the following three approaches using computational fluid dynamics (CFD) and experiments conducted with a multi-cooling engine system. First, the temperature rise of the air-fuel mixture by heat transfer from each part was analyzed.

It is well known that a high-pressure fuel injection is effective for the reduction in particulates and smoke emissions. Exhaust gas recirculation (EGR) is effective for the reduction in NOX emission. In this study an experiment aiming to understand more comprehensive combustion under the condition of EGR and high-pressure fuel injection was carried out by using gas sampling method for the purpose of understanding what occurred inside the spray before and after combustion. The number of combustion cycles in this engine can be controlled in order to change EGR conditions by adjusting the residual gas concentration in the cylinder. Main results were: (1) Close to the nozzle tip, the sampling gas data showed little reaction which implies that combustion never occurs in this area during the injection period. (2) In the case of high-pressure fuel injection O2 concentration decreased faster and air dilution was more active and earlier.

This paper describes a study of drag reduction devices for production pick-up trucks with a body-on-frame structure using full-scale wind tunnel testing and Computational Fluid Dynamics (CFD) simulations. First, the flow structure around a pick-up truck was investigated and studied, focusing in particular on the flow structure between the cabin and tailgate. It was found that the flow structure around the tailgate was closely related to aerodynamic drag. A low drag flow structure was found by flow analysis, and the separation angle at the roof end was identified as being important to achieve the flow structure. While proceeding with the development of a new production model, a technical issue of the flow structure involving sensitivity to the vehicle velocity was identified in connection with optimization of the roof end shape. (1)A tailgate spoiler was examined for solving this issue.

A continuously variable valve event and lift (VEL) system, actuated by oscillating cams, can provide optimum lift and event angles matching the engine operating conditions, thereby improving fuel economy, exhaust emission performance and power output. The VEL system allows small lift and event angles even in the engine operating region where the required intake air volume is small and the influence of valvetrain friction is substantial, such as during idling. Therefore, the system can reduce friction to lower levels than conventional valvetrains, which works to improve fuel economy. On the other hand, a distinct feature of oscillating cams is that their sliding velocity is zero at the time of peak lift, which differs from the behavior of conventional rotating cams. For that reason, it is assumed that the friction and lubrication characteristics of oscillating cams may differ from those of conventional cams.

There have been strong demands recently for reductions in the fuel consumption and exhaust emissions of diesel engines from the standpoints of conserving energy and curbing global warming. A great deal of research is being done on new emission control technologies using direct-injection (DI) diesel engines that provide high thermal efficiency. This work includes dramatic improvements in the combustion process. The authors have developed a new combustion concept called Modulated Kinetics (MK), which reduces smoke and NOx levels simultaneously by reconciling low-temperature combustion with pre-mixed combustion [1, 2]. At present, research is under way on the second generation of MK combustion with the aim of improving emission performance further and achieving higher thermal efficiency [3]. Reducing heat rejection in the combustion chamber is effective in improving the thermal efficiency of DI diesel engines as well as that of MK combustion.

The mechanism causing in-cylinder injector tip soot formation, which is the main source of particle number (PN) emissions under operating conditions after engine warm-up, was analyzed in this study. The results made clear a key parameter for reducing injector tip soot PN emissions. An evaluation of PN emissions for different amounts of injector tip wetting revealed that an injector with larger tip wetting forms higher PN emissions. The results also clarified that the amount of deposits does not have much impact on PN emissions. The key parameter for reducing injector tip soot is injector tip wetting that has a linear relationship with injector tip soot PN emissions.

The ways in which vehicles are used in the field are continually becoming more diverse. In order to provide the optimum solution with respect to performance and weight, it is necessary to be able to assure vehicle endurance reliability with a high degree of accuracy in relation to the manner of use in each market. This situation has increased the importance of accurately quantifying the ways in which vehicles are used in the field and of designing vehicles with sufficient endurance reliability to match the usage requirements. This report presents a “market model” by which the manner of usage in the field can be treated quantitatively using combinations of environmental factors that influence the road load, drive load and corrosion load, representing typical loads vehicles must withstand.

This paper concerns research on an emission control system aimed at reducing emission levels to well below the ULEV standards. As emission levels are further reduced in the coming years, it is projected that measurement error will increase substantially. Therefore, an analysis was made of the conventional measurement system, which revealed the following major problems. 1. The conventional analyzer, having a minimum full-scale THC range of 10 ppmC, cannot measure lower concentration emissions with high accuracy. 2. Hydrocarbons are produced in various components of the measurement system, increasing measurement error. 3. Even if an analyzer with a minimum full-scale THC range of 1 ppmC is used in an effort to measure low concentrations, the 1 ppmC measurement range cannot be applied when the dilution air contains a high THC concentration. This makes it impossible to obtain highly accurate measurements. 4.

Since the stable operating region of a gasoline-fueled HCCI engine is limited to the part load condition, a mode change between SI and HCCI combustion is required, which poses an issue due to the difference in combustion characteristics. This report focuses on the combustion characteristics in the transitional range. The combustion mode in the transitional range is investigated by varying the internal EGR rate, intake air pressure, and spark advance timing in steady-state experiments. In this parametric study, stable SI-CI combustion is observed. This indicates that the combustion mode transition is possible without misfiring or knocking, regardless of the speed of variable valve mechanism which includes VVA, VVEL, VTEC, VVL and so on, though the response of intake air pressure still remains as a subject to be examined in the actual application.

The probability or risk of traffic accidents must be estimated quantitatively in order to implement effective traffic safety measures. In this study, various statistical data and probability theory were used to examine a method for predicting the risk of crossing-collisions, representing a typical type of accident at intersections in Japan. Crossing-collisions are caused by a variety of factors, including the road geometry and traffic environment at intersections and the awareness and intentions of the drivers of the striking and struck vehicles. Bayes' theorem was applied to find the accident probability of each factor separately. Specifically, the probability of various factors being present at the time of a crossing-collision was estimated on the basis of traffic accident data and observation survey data.

Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio for improving thermal efficiency and downsizing the engine based on fuel-efficient operating conditions are good examples of technologies for enhancing gasoline engine fuel economy. A direct-injection system is adopted for most of these engines. Direct injection can prevent knocking by lowering the in-cylinder temperature through fuel evaporation in the cylinder. Therefore, direct injection is highly compatible with downsized engines that frequently operate under severe supercharging conditions for improving fuel economy as well as with high compression ratio engines for which susceptibility to knocking is a disadvantage.