In global warming issue, reduction of Carbon dioxide (CO₂) emission is needed for passenger vehicle. Our company developed a new generation 1.6L diesel engine as a part of technologies for high driving performance and good fuel economy. The dual Exhaust Gas Recirculation (EGR) system for achieving both good fuel economy and low emission are introduced in addition to our previous diesel engine, and met Euro5 emission regulation, and achieved 14.5 % reduction of CO₂ emission (94 g/km in NEDC mode). In this paper, the model based control for the dual EGR system using an intake throttle will be described.

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For further improvement in thermal efficiency of a heavy-duty diesel engine, heat balance calculation based on the first law of thermodynamics was applied to various engine operating conditions to find out the measures to improve brake work of the engine. And also, comparison of the heat loss from the wall calculated by the heat balance analysis with the heat loss calculated by the empirical formulas, i.e. Woschni’s / Eichelberg’s heat transfer coefficient was then carried out to explain a key factor for the difference between them in various engine test conditions.

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The enhancement of engine control technology contributed to higher thermal efficiency and lower emissions of diesel engines. This, however, caused increasing the number of control parameters, which resulted in the extension of engine calibration periods. To make the calibration process more efficient, Model Based Calibration (MBC) method has been attracted attention in recent years. The objective of this study is the construction of the new scheme of modeling engine performance with MBC method. In this paper, the zero-dimensional two-zone spray and combustion model was constructed, and the model accuracy was evaluated by comparison with conventional empirical models.

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Diesel-powered vehicles need to cope with diversified fuel quality and environment of use to achieve sales expansion in the world. Therefore, the total engine management system which integrates three technologies- the injection system components provided with fuel-robust structure, the control system which underpins them to assure optimum combustion, and the aftertreatment system which is capable of offering high conversion ratio under diversified cruise conditions and environments as well as controlling lowered fuel efficiency- has been developed by authors.

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The authors proposed a fuel design concept for an HCCI engine to optimize a profile of heat release and achieve a robust ignition process. The concept was validated by engine operation tests using methane-based dual-component fuels at a low speed and a low load in the previous study, and has been done at a high speed and a high load in the present study. Methane/ethane demonstrates a lower COV of IMEP than those of methane/propane, methane/n-butane and methane/isobutane, when the timing of 50 % heat release is set at the same crank angle in the expansion stroke. It is because according to 0-dimensional chemical kinetic computations, ethane indicates a higher heat release rate in the late stage of an ignition process than propane, n-butane and isobutane do. Methane/ethane also demonstrates a lower knocking intensity than those of the other dual-component fuels, when the timing of 50 % heat release is set at the same crank angle close to the knocking limit. Methane/ethane indicates a lower gradient of the heat release rate immediately before the heat release rate reaches the peak value, which moderates the pressure rise rate and suppresses knocking.

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This paper deals with stochastic control problems with spark advance as control actuator. First, a likelihood estimation based knock control approach is presented by combining the likelihood estimation of cyclic knocking probability with adjusting the spark advance based on the pre-specified threshold of likelihood ratio. Then, this approach is extended to take the peak pressure location into account. Finally, the experiment validation results of the proposed control approaches are demonstrated on a gasoline engine test bench.

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In this study, the thermal flow of the piston had been focused on, and a predictive method for piston temperature was developed using the Total Engine Simulation System (TESS), which can predict thermal flow of engine, consisting of 0-dimensional diesel combustion model, gas flow model and heat transfer model. The piston mass elements were divided to the thermal capacity element considering the temperature gradient of the piston in operating condition of the engine. As a result, when operating condition changed, the tendency of the piston temperature was able to predict with this method.

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As is already reported new combustion method named PCC(Plume Ignition Combustion Concept), which realized combustion of plume of rich hydrogen mixture by igniting injected hydrogen jet in the period of or just after the injection, is effective to reduce NOx formation drastically without offering any trade-offs on thermal efficiency in high output power operation in direct injection hydrogen engines. In this study it was made clear that increased unburned hydrogen decreased thermal efficiency in high lambda premixed operating condition which is commonly used in part load operation of direct injection hydrogen engines. This is thought to be caused by partially incomplete flame propagation occurred in high lambda portion of the non-uniform mixture that presents with slowing burning even in hydrogen engines. It was also found that the PCC combustion was effective to improve thermal efficiency by suppressing increase in unburned hydrogen under the operating condition mentioned above. The effect is understood to be caused by reducing dispersion of hydrogen mixture to form high lambda that presents with the incomplete flame propagation.

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Particle formation and oxidation processes in diesel combustion are investigated from the point of view of instantaneous and spatial characteristics by using a CFD code which accounts for finite-rate elementary chemical reactions coupled with the phenomenological multiple steps soot model. Impacts of higher pressurized injection on formation and oxidation processes of sooting phenomena are analyzed.

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Low-Speed Pre-Ignition (LSPI) is one of the key issues for developing highly boosted direct injection spark-ignition engines for passenger cars. In this report, based on the hypothesis that LSPI is triggered by ignition of droplets containing lubricant, a constant volume chamber was used to observe and comprehend ignition characteristics of a lubricant. In addition, a multi-dimensional CFD code was utilized to determine chemical ignition characteristics. The result shows that the lubricant has extremely high ignitability. Thus, it is probable that the droplets containing lubricant are a major cause of LSPI.

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New combustion strategies with EGR are recently applied for the purpose of not only reducing pumping loss but also improving anti-knocking and compression ratio in gasoline engines. This paper describes effects of ignition coil specifications (current, duration and energy) on combustion performance of a spark ignition engine. To clarify better parameters’ settings which affect stoichometric combustion with EGR, a robust design, named Taguchi Methods was used as a sensitivity analysis. With suitable parameters selected, combustion stability under higher EGR was investigated to determine requirements of ignition specifications for new combustion strategies. The results showed that multiple-ignition contributes to improve the limitation of EGR rate.

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Free Piston Engine Linear Generator (FPEG) with features of thin and compact build, high efficiency and high fuel flexibility is developed. The key technologies for enabling stable continuous operation are lubricating, cooling, and control logic. This paper describes the main structure and operation characteristics of the FPEG, including the unique piston motion and its effect on combustion and power generation.

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Free Piston Engine Linear Generator system (FPEG) with features of thin and compact build, high efficiency, and high fuel flexibility is developed. To realize stabilized combustion and efficient power generation, a precise piston motion control method was established. The developed control system consists of a three-phase linear synchronous generator driven by a three-phase inverter and a DSP controller. This FPEG system is able to start by itself using the generator as a motor, therefore it doesn’t need any additional starting devices. It has been proved that the FPEG system is operated stably for a long period on a test bench.

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To achieve high safety and efficient battery system, predicting internal transport phenomena of commercial lithium ion batteries under HEVs or EVs driving conditions become more important because these phenomena can uncover battery limitations. In this study, a pseudo 2D model has been developed by finite volume method to be used for analyzing each over-voltage under EV driving condition, JC08 test cycle. As a result, the main reason of energy loss reduction due to voltage fluctuation is lithium ion (salt) transfer in an electrolyte under transient or pulse conditions compared with those under constant current conditions.

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Correlation between WorldSID injury values and side door intrusion velocity for side impact is studied by the simplified side impact simulation. In this simulation, side door and side air bag are modeled by plates and springs. By comparing the response characteristic of WorldSID and ES-2, it turned out that it is necessary for WorldSID to reduce the side door intrusion velocity than ES-2. Furthermore, the validity of this correlation was indicated by vehicle crash test.

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Recently various driving support systems have been developed to improve safety and reduce driver’s stress. It is necessary to design systems based on information that human driver perceives and gives better feeling of confidence. In order to clarify the information, we focused on optical sensation. Optical flow on retina reflects vehicle movement and eye movement. In this paper, numerical simulation was done to analyze the characteristic of optical flow, and relation to the driver models proposed in the past are also discussed.

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The relationship between near-miss incidents, as a substitute characteristic for traffic accidents, and driver behavior indexes was made clear in order to develop a method of quantitatively assessing safe driver behavior based on accident risk. Several driver behavior indexes were first formulated from actual accident circumstances, focusing on crossing-path accidents at stop sign intersections, which frequently occur in Japan. Using a naturalistic driving database, driver behavior indexes correlated with near-miss incidents were then identified. The indexes were then validated by conducting driving tests in a proving ground to clarify the respective mechanism leading from such driver behavior to near-miss incidents.

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We measured a driver’s mental load for the operation of a navigation system, using a multi-modal stimulus detection task (MSDT) in a driving simulation and in actual driving. Under both experimental environments, the participants drove while performing navigation system operation tasks and the MSDT. The MSDT imposed stimulus detection with visual, tactile, and auditory modalities on participants.Most of the detection performance indices showed the same deteriorations in both environments. These results indicate that the MSDT evaluated the mental load of navigation system operation to a certain extent in both environments.

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The effect of wheel shape on the aerodynamic drag of a road vehicle was investigated. The special focus is on the correlation of the drag between an isolated wheel without vehicle body and an entire vehicle the wheel is mounted on. A positive correlation was confirmed by numerical simulation and wind-tunnel measurements. The mechanism of generating the aerodynamic drag was found to be similar between the isolated wheel and that mounted on the vehicle body. These results suggest the possibility of estimating the effect of wheel shape upon the drag coefficient of the vehicle by the isolated wheel analysis.

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The exhaust emission profiles of regulated gases, PM, PN and 2.5PN for the latest HD engine equipped with DPF and Urea SCR system were investigated. The profiles were observed in long range and included DPF regeneration. The NOx emission increase was observed during the regeneration due to falling NOx removal efficiency of the SCR system. PM, PN and 2.5 PN emissions were also increased in the cycle with the regeneration. The results of PM composition analysis using ion chromatography indicated the ratio of nitric acid ion was high corresponding to NOx removal by urea-SCR. The main species in the exhaust which contained nitric acids is not nitrate ammonium.

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Depending on the diversification of liquid fuel sources, changes in diesel fuel composition are expected. These changes may increase the gap between cetane index and cetane number. Therefore, enhanced cetane index formula which has higher predictive performance is required. In this study, we focused on the chemical structures which affect the auto-ignition characteristics. Specifically, the chemical structures mean carbon number, number of side chains, the rate of naphthenic rings, and the rate of aromatic rings. Characteristics of these structures in diesel fuel can represented by the specific combination of physical properties, namely, distillation characteristic, kinetic viscosity and density. Now, therefore, enhanced cetane index formula is described by three physical parameters mentioned above.

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Dent resistance and surface distortion were deteriorated by reduction of outer panel thickness. Therefore, it becomes difficult to reduce automotive body weight. Effective factors on these properties were evaluated quantitatively with the aim of securing these properties. As a result, tensile strength 440 MPa grade bake harden able (BH) steel sheet was superior to conventional steel sheets in dent resistance and surface distortion property.

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The effect of friction coefficient on press formability of high strength steel sheet was investigated in this paper. Labo-scale forming test was conducted as press forming test. Galvannealed mild steel sheet and high strength steel sheet were used as base material, and in order to change the friction coefficient three type surfaces were prepared on the same base material. One was as received; galvannealed steel sheet (GA), second was surface modified GA and the third was GA whose surface covered with polystyrene sheet. It was found that both drawability and stretch formability of high strength steel sheet tends to increase with decrease of the friction coefficient. In addition, the effect of friction coefficient on stretch formability was changed depending on punch shoulder radius in stretch formability. The influence of lubrication on drawability and stretch formability and of punch shoulder radius on stretch formability was discussed.

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