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Estimating distant road structure will be an important factor in determining the extent of danger of detected obstacles. There are some methods to estimate the road structure by an image from an onboard camera. However, the results are not sufficient due to the vertical curvature of roads and the limitation of image resolution. In this paper, a new method is proposed to estimate the 3-D road structure by fusion of a 2-D digital road map and an image from a camera. The effect of this method is confirmed by using synthesized data and actual data.

Temperature distributions on the surface of a connecting rod big end bearing were measured to understand the margin to the allowable limiting temperature. The results show that the temperature difference between the bearing surface and the feed oil is independent of the engine load but quadratically increased with the engine speed, and that the bearing surface temperature on the rod side is higher than those on the cap side, and that the high temperature regions appeared near the edges on the rod side of the bearing under high speed operations. The results were analyzed by the observation of rubbing traces on the bearing surface and the EHD lubrication theory.

Engine running tests and excitation tests were performed to reveal the vibration behavior in a turbocharger-exhaust system related to the turbocharger's operating sound. The operating sound was caused by the resonant vibration excited by the unbalanced inertia force of the rotor. The turbocharger-exhaust system had six resonant frequencies in the operating speed range of the rotor. At resonant speeds, the whole turbocharger was translating or rotating due to bending and torsional deflection of the exhaust manifold. Based on the test results, the vibration behavior could be well simulated by a rigid body-spring model with six degree of freedom. Furthermore, the model was used to analyze the relation between the stiffness of the exhaust manifold and the vibration level. Increasing the stiffness of the exhaust manifold was effective in sufficiently reducing the vibration and sound.

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.

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.

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.

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 study was conducted to reduce unburned oil fractions in diesel particulate matter (PM) by improving oil consumption. A method utilizing radioisotope 14C was developed to measure the unburned oil fractions separately for the four paths by which oil is consumed: valve stem seals, piston rings, PCV system, turbocharger. The conversion ratio of oil consumption to PM was calculated by comparing the unburned oil emission rates with oil consumption rates, which were obtained by the use of the 35S tracer method. The result in an experimental diesel engine shows the highest conversion ratio for the oil leaking through the valve stem seals. The modifications to the engine were thereby focused on reducing the leakage of the stem seals. This stem seal modification, along with piston ring improvements, reduced oil consumption, resulting in the unburned oil fractions in PM being effectively reduced.

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.

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.

Three-dimensional numerical analysis of fuel liquid and mixture behavior in a port-injection gasoline engine is assessed by comparing calculations with measurements. The fuel mass distributed in the intake port and cylinder is measured using an engine with hydraulic valve and gas sampling system. The experimental results show that about half of the fuel mass per injection enters the cylinder, and the rest stays in the port. The difference of the mass fraction of injected fuel directly entering the cylinder is small between the cases of single pulse injection and serial injection. Therefore, three-dimensional calculation presupposing single pulse injection has difficulty in predicting the in-cylinder mixture formation process, although it can analyze the amount of fuel wetting the port wall. The calculations are performed for a port-injection engine, and the differences of fuel behavior with respect to swirl control valve opening and wall temperature are discussed.

The laser-induced exciplex fluorescence (LIEF) technique, currently used to observe mixture formation in a diesel engine, has been applied to a spark ignition (SI) engine and a new equivalence ratio calibration technique has been developed in order that two-dimensional measurements of the equivalence ratio may be made in an operating engine. Spectrally separated fluorescent images of liquid and vapor phase fuel distributions were obtained by adding new exciplex-forming dopants to the gasoline fuel. Dual light sheets from an excimer laser were introduced into one of the cylinders of a 4-valve lean-burn engine, and 2-D images of the mixture formation were recorded at pre-set crank angles during the induction and compression strokes by an image-intensified camera equipped with the appropriate filter.

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.

The influence of engine oil viscosity on the wear of piston rings and cam faces has been investigated by fired engine tests using a radioisotope (RI) tracer technique. High-temperature and high-shear-rate (HTHS; 150°C, 1O6 s-1) viscosities of the experimental oils prepared are 2.2, 2.4, 2.6 and 3.1 mPa•s. At an oil temperature of 90°C the wear of piston rings and cam faces did not increase, even if the HTHS viscosity was lowered down to 2.2 mPa•s. However, both piston rings and cam faces exhibited an increase in wear below 2.4 mPa•s at 130°C. It was also recognized that valve train wear did not significantly increase with reducing viscosity in the motored engine tests at a temperature of 50°C. From these test results, it was suggested that the oil with the HTHS viscosity of 2.6 mPa•s sufficiently demonstrates the antiwear performance equivalent to that with around 3.0 mPa•s for application to piston rings and cam faces.

The properties of diesel fuels were investigated in terms of particulate emissions to clarify the specification of such a diesel fuel for minimizing particulate emissions. Diesel fuels were analyzed using thin layer chromatography (TLC), and gas chromatography/mass spectrometry (GC/MS). These analysis revealed the entire composition of hydrocarbons in diesel fuels according to molecular formula. The entire composition of hydrocarbons in diesel fuels could be expressd on a three-dimensional graph: the X-axis as carbon number, the Y-axis as H/C ratio and the Z-axis as the amount of hydrocarbons of identical molecular formula. By using the graph, the properties reported so far were investigated. Also, simplified images of the fuel sprayed into a cylinder and its flame were derived from the observational results previously reported.

A new experimental apparatus to visualize and measure the flow in the stator of a torque converter is proposed. A one-sided coaxial shaft constructed of an input shaft and an output shaft provides an open space inside the stator shaft for measurement. Through the window on the stator shaft, the flow in the stator can be directly observed. We also improved the laser sheet lighting method into the blade passage by using a mirror inside the blade. By visualizing the flow with the laser sheet lighting method, we found that the flow around the leading edge has different separation regions along the blade span. Furthermore, by using a laser doppler velocimeter, velocity vectors and turbulence intensities were measured in three stator blades of different thicknesses with the same camber line. The thickness of the stator blades affects the flow patterns.

The EHD lubrication model of connecting rod big end bearings is compared with experiments using an automotive diesel engine. The axial load and the bending moment near the middle of rod length were derived from strain measurements and compared with the theoretical results based on engine dynamics. Although oscillation appeared on bending moment at 5000 rpm, the theoretical load almost agreed with the experiment. The EHD lubrication theory and the experiments were compared by the histories of clearances and the journal center orbits in the bearing. The theoretical results agreed well with the experimental one. The deformation of the bearing appeared both in the theory and in the experiment at 3000 rpm or above; these results confirm the necessity of the EHD lubrication theory.

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 technique has been developed that uses unsteady flow simulation to evaluate mirror vibration quantitatively at the drawing stage. Studies made in actual driving tests of the contributions of different inputs to mirror vibration have confirmed that the contribution of fluid force is large, so a visualization of the structure of the external rearview mirror wake was done using PIV. The results made it clear that the vibration imparted to the mirror surface by air flow excites the natural vibration mode of the mirror surface, thereby causing the mirror to vibrate. Mirror vibration performance was evaluated by means of unsteady flow simulation using the moment PSD as a substitute characteristic. (The moment PSD was obtained by a frequency analysis of the changes over time in the moment generated in the mirror surface by the fluid force.) The results obtained through CFD show a high degree of correlation with those obtained in actual driving tests.

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.