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This report describes the implementation of the spark channel short circuit and blow-out submodels, which were described in the previous report, into a spark ignition model. The spark channel which is modeled by a particle series is elongated by moving individual spark particles along local gas flows. The equation of the spark channel resistance developed by Kim et al. is modified in order to describe the behavior of the current and the voltage in high flow velocity conditions and implemented into the electrical circuit model of the electrical inductive system of the spark plug. Input parameters of the circuit model are the following: initial discharge energy, inductance, internal resistance and capacitance of the spark plug, and the spark channel length obtained by the spark channel model. The instantaneous discharge current and the voltage are obtained as outputs of the circuit model.

This study models short circuits and blow-outs of spark channels. The short circuit model assumes that a spark channel is short-circuited between two arbitrary locations when the electric potential difference between the two locations exceeds the voltage which enables electrical insulation breakage in-between. The threshold voltage can be raised by increasing the distance between the two locations and decreasing the discharge current. Discharge current, in this model, represents the influence of both the spread and the number of electrically charged particles, i.e., electrons and positive ions, distributed near the two locations. Meanwhile, the blow-out model assumes that a strong flow diffuses electrons and positive ions in the spark channel, and consequently the discharge blows out.

With the goal of improving drivability, this research aimed to clarify the mechanism of vehicle longitudinal acceleration, focusing on tip-in acceleration. Conventional typical analysis methods include experimental modal and model-based analysis. However, since the former requires the measurement of impulses and other input forces while the vehicle is stopped, measurement under actual driving conditions is difficult. The latter requires characteristic values such as the stiffness and damping coefficients to be identified in advance, which cannot be achieved either easily or precisely. Therefore, this paper proposes a new experiment-based analysis method. This method enables the acquisition of engine torque and transmission torque/force by measuring only the acceleration values of some components under driving conditions.

The backward flow of the hot burned gas surrounding a diesel flame was found to be one of the factors dominating the set-off length (also called the lift-off length), that is, the distance from a nozzle exit into which a diffusion flame cannot intrude. In the combustion chamber of an actual diesel engine, the entrainment of the surrounding gas into a spray jet from a multi-hole nozzle is restricted by the walls and adjacent spray jets, which induces the backward flow of the surrounding gas. A new momentum theory to calculate the backward flow velocity was established by extending Wakuri's momentum theory. Shadowgraph imaging in an optical engine successfully visualized the backward flow of the hot burned gas.

In diesel engines with a straight intake port and a lipless cavity to restrict in-cylinder flow, an injector with numerous small-diameter orifices with a narrow angle can be used to create a highly homogeneous air-fuel mixture that, during PCCI combustion, dramatically reduces the NOX and soot without the addition of expensive new devices. To further improve this new combustion concept, this research focused on cooling losses, which are generally thought to account for 16 to 35% of the total energy of the fuel, and approaches to reducing fuel consumption were explored. First, to clarify the proportions of convective heat transfer and radiation in the cooling losses, a Rapid Compression Machine (RCM) was used to measure the local heat flux and radiation to the combustion chamber wall. The results showed that though larger amounts of injected fuel increased the proportion of heat losses from radiation, the primary factor in cooling losses is convective heat transfer.

Over the last few decades, in-cylinder visualization using optically accessible engines has been an important tool in the detailed analysis of the in-cylinder phenomena of internal combustion engines. However, most current optically accessible engines are recognized as being limited in terms of their speed and load, because of the fragility of certain components such as the elongated pistons and transparent windows. To overcome these speed and load limits, we developed a new generation of optically accessible engines which extends the operating range up to speeds of 6000 rpm for the SI engine version, and up to in-cylinder pressures of 20 MPa for the CI engine version. The main reason for the speed limitation is the vibration caused by the inertia force arising from the heavy elongated piston, which increases with the square of the engine speed.

In the case of engine bearings, pressure in a cylinder is necessary for the analysis of lubrication. In this study, a cycle simulation of gasoline engines has been developed to predict the pressure in the cylinder under the wide range of engine operation. In the cycle simulation, intake and exhaust processes are included and combustion process is calculated with flame propagation based on burning velocity. Here, the equation of ignition delay and the equation of burning velocity were determined with experimental results of a gasoline engine over wide A/F ratio. The pressure in the cylinder over the engine cycle is introduced into an elastohydrodynamic lubrication analysis of a con-rod bearing to calculate the load on the bearing in addition to the inertia force. Orbital movement, minimum film thickness, and power loss in the bearing were estimated over the wide range of engine operation.

Toyota participated in Formula One1 (F1) Racing from 2002 to 2009. As a result of the downturn in the world economy, various engine developments within F1 were restricted in order to reduce the cost of competing in F1. The limit on the maximum number of engines allowed has decreased year by year. Toyota focused on the engine performance deterioration due to the combustion chamber deposits. In 2009, Toyota was successful in reducing around 40% of the deterioration by making combustion chamber cleaner in cooperation with ExxonMobil. This contributed to good result of 2009 F1 season for Toyota, including two second place finishes.

The finite element method (FEM) is effective for analyzing brake squeal phenomena. Although FEM analysis can be used to easily obtain squeal frequencies and complex vibration modes, it is difficult to identify how to modify brake structure design or contact conditions between components. Therefore, this study deals with a practical design method using sensitivity analysis to reduce brake squeal, which is capable of optimizing both the structure of components and contact conditions. A series of analysis processes that consist of modal reduction, complex eigenvalue analysis, sensitivity analysis and optimization analysis is shown and some application results are described using disk brake systems.

Natural gas homogeneous charge compression ignition (HCCI) engines require high compression ratios and intake air heating because of the high auto-ignition temperature of natural gas. In the first study, the natural gas fueled HCCI combustion with internal exhaust gas recirculation (EGR) was achieved without an intake air heater. The effects of the combustion chamber configuration, turbocharging, and external EGR were investigated for expanding the operating range. As a result, it was cleared that the combination of internal / external EGR and turbocharging is effective for expanding the HCCI operational range toward high loads. Meanwhile, the HCCI combustion characteristics at high engine speeds were unstable because of an insufficient reaction time for auto-ignition. Although the engine operation with a richer air-fuel ratio was effective for improving the combustion stability, the combustion noise (CN) was at an unacceptable level.

Two-line excitation LIF (Laser-Induced Fluorescence) technique for 2-dimensional temperature measurements in an engine cylinder before ignition is presented. From the fundamental examinations, the combination of toluene tracer with a pair of excitation lines of 248nm and 266nm has been selected because of the high LIF intensity ratio and closer excitation wavelengths. In-cylinder thermometry is conducted using a visualized single cylinder spark ignition engine both in PFI (port-fuel-injection) and DI (direct-injection) operation. The accuracy of this technique is determined through the homogeneous PFI experiment. Temperature and fuel distribution in unburned mixture are measured simultaneously in DI operation. It exists a strong correlation between equivalence ratio and temperature inside the mixture. Temperature in the fuel rich region is lower than in the fuel lean region.

A concept of dual-fuel, Premixed Compression Ignition (PCI) combustion controlled by two fuels with different ignitability has been developed to achieve drastically low NOx and smoke emissions. In this system, isooctane, which was used to represent high-octane gasoline, was supplied from an intake port and diesel fuel was injected directly into an engine cylinder at early timing as ignition trigger. It was found that the ignition timing of this PCI combustion can be controlled by changing the ratio of amounts of injected two fuels and combustion proceeds very mildly by making spatial stratifications of ignitability in the cylinder even without EGR, as preventing the whole mixture from igniting simultaneously. The operable range of load, where NOx and smoke were less than 10ppm and 0.1 FSN, respectively, was extended up to 1.2MPa of IMEP using an intake air boosting system together with dual fueling.

The performances of some vehicle control systems are influenced by changes in the weight of the vehicle. In these systems, it is important to be able to estimate the weight without the need for special sensors. When we use physical models to do this, we have to provide estimates for two or more unknown parameters. In addition, since such a method is influenced by disturbances in the measured signals, it is difficult to maintain an acceptable level of accuracy. So, after analyzing the physical phenomena, we developed a new method that eliminates the influence of the disturbances from the measured signals and constructed an estimation system that has a minimum number of unknown parameters that was capable of providing a more accurate estimate of a vehicle weight. This method was applied to the braking force control of an automatic transmission and its efficacy was verified.

Several three-dimensional (3D) finite element (FE) models of the human body have been developed to elucidate injury mechanisms due to automotive crashes. However, these models are mainly focused on 50th percentile male. As a first step towards a better understanding of injury biomechanics in the small female, a 3D FE model of a 5th percentile female human chest (FEM-5F) has been developed and validated against experimental data obtained from two sets of frontal impact, one set of lateral impact, two sets of oblique impact and a series of ballistic impacts. Two previous FE models, a small female Total HUman Model for Safety (THUMS-AF05) occupant version 1.0ϐ (Kimpara et al., 2002) and the Wayne State University Human Thoracic Model (WSUHTM, Wang 1995 and Shah et al., 2001) were integrated and modified for this model development.

We have proposed First Order Analysis (FOA) as a method, which the engineering designers themselves can use easily in an initial design stage. In this paper, we focus on the crashworthiness, and present the method to predict the collapse behavior of the frame member. This method is divided into two parts. Those are (1) collapse analysis under loading conditions of combined axial force and bending moment to the cantilever, and (2) collapse analysis of structural member considering the previously obtained moment - rotation angle relationship using the beam element. In comparison with the results according to the detailed Finite Element Analysis (FEA) model, effectiveness and validity of this method are presented.

The stoichiometric direct injection gasoline engines have higher torque performance than the port injection engines, as the volumetric efficiency can be increased due to the cooling effects of charging air by the fuel evaporation in the cylinder. They need only 3-way catalyst, leading to the cost down. However there exists the injection timing (region) that increased volumetric efficiency does not lead to higher torque. In order to investigate the phenomena, the in-cylinder mixture formation process has been analyzed by the LIF and the CFD techniques. As the results, it has been revealed that the phenomena are caused by the inhomogeneous mixture distribution before the ignition timing.

The cause of the exhaust smoke and its reduction methods in a small DI Diesel engine with a small-orifice-diameter nozzle and common rail F.I.E. were investigated under high-speed and high-load condition, using both in-cylinder observations and Three-dimensional numerical analyses. The following points were clarified during this study. At these conditions, fuel sprays are easily pushed away by a strong swirl, and immediately flow out to the squish area by a strong reverse squish. Therefore, the air in the cavity is not effectively used. Suppressing the airflow in a piston cavity, using such ideas as enlarging the piston cavity diameter or reducing the port swirl ratio, decreases the excessive outflow of the fuel-air mixture into the squish area, and allows the full use of air in the whole cavity. Hence, exhaust smoke is reduced.

A new stratified charge combustion system has been developed for direct injection gasoline engines. The special feature of this system is employment of a thin fan-shaped fuel spray formed by a slit nozzle. The stratified mixture is produced by the combination of this fan-spray and a shell-shaped piston cavity. Both under-mixing and over-mixing of fuel in the stratified mixture is reduced by this system. This combustion system does not require distinct charge motion such as tumble or swirl, which enables intake port geometry to be simplified to improve full load performance. The effects of the new system on engine performance at part load are improved fuel consumption and reduced smoke, CO and HC emissions, obviously at medium load and medium engine speed. HC emissions at light load are also improved even with high EGR conditions.

A multi-component fuel vaporization model is developed for numerical analysis of specific fuel component behaviors in port-fuel-injection(PFI) gasoline engines. In order to specify the differences of in-cylinder fuel distribution among its components, three-dimensional calculations of intake flow, spray and vapor motion of each component are performed with respect to engine wall temperature and the distillation characteristics of the fuel. Simultaneous measurements of in-cylinder behaviors of different volatility components in the fuel are also carried out using a laser-induced fluorescence (LIF) technique to validate the calculation results. In both measurements and calculations, the same fuels are used, which are composed of seven or eight components to simulate the distillation characteristics of two kinds of gasoline. The in-cylinder vapor amount of high and low volatility components is compared between the calculations and the experiments.

The schlieren visualization of in-cylinder processes from the side of an engine cylinder is useful to understand the phenomena which change along the cylinder axis. A transparent collimating cylinder, TCC, permits schlieren observation inside the cylinder through its transparent wall. In this study, a single cylinder visualization engine with the TCC was applied to a direct-injection gasoline engine. A fuel spray, mixture formation and combustion were observed with a simultaneous measurement of in-cylinder pressure. The shape of the fuel spray and subsequent mixture formation process are drastically changed with the injection timing. The images of luminous flame were also taken with the schlieren images during the combustion period. Stable combustion, misfire and abnormal combustion are discussed with the comparison between the observed results and in-cylinder pressure analysis.