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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.

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.

The hole diameter of injection nozzles in diesel engines has become smaller and the nozzle coking could potentially cause injection characteristics and emissions to deteriorate. In this research, engine tests with zinc-added fuels, deposit analyses, laboratory tests and numerical calculations were carried out to clarify the deposit formation mechanisms. In the initial phase of deposit formation, lower zinc carboxylate formed close to the nozzle hole outlet by reactions between zinc in the fuel and lower carboxylic acid in the combustion gas. In the subsequent growth phase, the main component changed to zinc carbonate close to nozzle hole inlet by reactions with CO₂ in the combustion gas. Metal components and combustion gases are essential elements in the composition of these deposits. One way of removing these deposits is to utilize cavitations inside the nozzle holes.

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.

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.

In this paper, we will introduce a stereo vision system developed as a sensor for a vehicle's front monitor. This system consists of three parts; namely, a stereo camera that collects video images of the forward view of the vehicle, a stereo ECU that processes its output image, and a near-infrared floodlight for illuminating the front at night. We were able to develop an obstacle detection function for the Pre-Crash Safety System and also a traffic lane detection function for a Lane-Keeping Assist System. Especially in regard to the obstacle detection function, we were able to achieve real-time processing of the disparity image calculations that had formerly required long processing times by using two types of recently developed LSIs.

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.

A series calculation methodology from the injector nozzle internal flow to the in-cylinder fuel spray and mixture formation in a diesel engine was developed. The present method was applied to a valve covered orifice (VCO) nozzle with the recent common rail injector system. The nozzle internal flow calculation using an Eulerian three-fluid model and a cavitation model was performed. The needle valve movement during the injection period was taken into account in this calculation. Inside the nozzle hole, cavitation appears at the nozzle hole inlet edge, and the cavitation region separates into two regions due to a secondary flow in the cross section, and it is distributed to the nozzle exit. Unsteady change of the secondary flow caused by needle movement affects the cavitation distribution in the nozzle hole, and the spread angle of the velocity vector at the nozzle exit.

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 stratification feature of DI gasoline combustion was studied by using a constant volume combustion vessel. An index of stratification degree, defined as volumetric burning velocity, has been proposed based on the thermodynamic analysis of the indicated pressure data. The burning feature analysis using this stratification degree and the fuel vapor concentration measurement using He-Ne laser ray absorption method were carried out for the swirl nozzle spray with 90° cone angle and the slit nozzle spray with 60° fan angle. Ambient pressure and ambient temperature were changed from atmospheric condition to 0.5∼0.6 MPa and 465 K, respectively. Air Swirl with swirl ratio of 0∼1.0 were added for the 90° swirl nozzle spray. Single component fuels with different volatility and self-ignitability from each other were used besides gasoline fuel. The major findings are as follows. High ambient temperature improves stratification degree due to the enhanced fuel vaporization and vapor diffusion.

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.

In direct-injection (DI) gasoline engines, spray characteristics greatly affect engine combustion. For the rapid development of new gasoline direct-injectors, it is necessary to predict the spray characteristics accurately by numerical analysis based on the injector nozzle geometry. In this study, two-phase flow inside slit nozzle injectors is calculated using the volume of fluid method in a three-dimensional CFD. The calculation results are directly applied to the boundary conditions of spray calculations, of which the submodels are recently developed to predict spray formation process in direct injection gasoline engines. The calculation results are compared with the experiments. Good agreements are obtained for typical spray characteristics such as spray shape, penetration and Sauter mean diameter at both low and high ambient pressures. Two slit nozzle injectors of which the slit thickness is different are compared.

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.

Our concern was with the phenomenon of the fuel flow rate change in the injector due to deposit formation in the direct injection gasoline engine. The fundamental factors in the deposit formation on the nozzle were investigated, and engine dynamometer tests were performed. It was clarified that the residual fuel in the nozzle hole should be kept in a liquid state so that deposit precursors could be washed away by fuel injections. As a consequence, the nozzle temperature had to be below the 90 vol. % distillation temperature of the fuel, which was the most important index to suppress the deposit formation.