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This paper presents typical flow structures around a 60%-scale wind-tunnel model of a Formula One (F1) car, using planar particle image velocimetry (PIV). The customized PIV system is permanently installed in a wind tunnel to help aerodynamicists in the development loop. The PIV results enhance the understanding of the mean velocity field in the two-dimensional plane in some important areas of the car, such as the front-wheel wake and the underfloor flow. These real phenomena obtained in the wind tunnel also help maintain the accuracy of simulations using computational fluid dynamics (CFD) by allowing regular checking of the correlation with the real-world counterpart. This paper first surveys recent literature on unique flow structures around the rotating exposed wheel, mostly that on the isolated wheel, and then gives the background to F1 aerodynamics in the late 2000s.

The effects of an increasing boost pressure, a high EGR rate and a high injection pressure on exhaust emissions from an HSDI (High Speed Direct Injection) diesel engine were examined. The mechanisms were then investigated with both in-cylinder observations and 3DCFD coupled with ϕT-map analysis. Under a high-load condition, increasing the charging efficiency combined with a high injection pressure and a high EGR rate is an effective way to reduce NOx and soot simultaneously, which realized an ultra low NOx of 16ppm at 1.7MPa of IMEP (Indicated Mean Effective Pressure). The flame temperature with low NOx and low soot emissions is decreased by 260K from that with conventional emissions. Also, the distribution of the fuel-air mixture plot on a ϕT-map is moved away from the NOx and soot formation peninsula, compared to the conventional emissions case.

A new clean diesel combustion concept has been proposed and its excellent performance with respect to gas emissions and fuel economy were demonstrated using a single cylinder diesel engine. It features the following three items: (1) low-penetrating and highly dispersed spray using a specially designed injector with very small and numerous orifices, (2) a lower compression ratio, and (3) drastically restricted in-cylinder flow by means of very low swirl ports and a lip-less shallow dish type piston cavity. Item (1) creates a more homogeneous air-fuel mixture with early fuel injection timings, while preventing wall wetting, i.e., impingement of the spray onto the wall. In other words, this spray is suitable for premixed charge compression ignition (PCCI) operation, and can decrease both nitrogen oxides (NOx) and soot considerably when the utilization range of PCCI is maximized.

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.

A method of real time oil concentration measurment has been developed utilizing the effect of ultraviolet light absorption by lubricating oil in the liquid refrigerant line of an automotive air conditioning system. The light wavelengths from 200nm to 370nm are selected based on the ultraviolet light absorption sensitivity of the oils and refrigerants (CFC12,HFC134a). The effects of temperature,pressure and contaminantion on the absorbance of light are investigated in order to determine how these parameters affect the concentration measurement. The density changes of refrigerants are then compensated in the calculation for the oil concentration. The uncertainties of the overall concentration measurement are less than ±0.1 weight percent at 1 weight percent concentration. A transient oil circulation of the automotive air conditioner is measured by using this method.

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.

A study of diesel fuel as a lubricant for diesel engines was conducted with the aim of dramatically reducing engine friction and eliminating the need to change the lubricating oil. A prototype single-cylinder engine modified for diesel fuel lubrication was made, and it was confirmed that firing operation is possible. Piston friction during the firing operation was reduced by modifying the shape of the cylinder liner surface to improve the retention of the lubricating oil. The study produced valid findings concerning engine lubrication, not only with diesel fuel, but also with ultra-low viscosity oil.

In recent years, problems such as global warming, the depletion of natural resources, and air pollution caused by emissions are emerging on a global scale. These problems call for efforts directed toward the development of fuel-efficient engines and exhaust gas reduction measures. As a solution to these issues, performance improvements should be achieved on the oil that lubricates the sliding sections of engines. This report points to features required of future engine oil-such as contribution to fuel consumption, minimized adverse effects on the exhaust gas aftertreatment system, and improved reliability achieved by sludge reduction-and discusses the significance of these features. For engine oil to contribution of engine oil to lower fuel consumption, we examined the effects of reduced oil viscosity on friction using gasoline and diesel engines.

The original Toyota Hybrid System (THS) was installed in the Prius and was introduced in 1997 as the world's first mass-produced hybrid passenger car. Since then, THS has been continuously improved. In 2003 THS-II (marketed as Hybrid Synergy Drive [HSD]), was installed in a new larger Prius. In 2006 HSD was installed in a Rear Wheel Drive Vehicle: the LEXUS GS450h. This system achieved both 4.5-liter class power performance and compact class fuel economy with outstanding emissions performance. In 2007, this system is expanded to a mechanical all-wheel-drive(AWD) in the LEXUS LS600hL(with new V8 engine). This paper will explain this hybrid system which achieved both V12 class power performance and mid-size class fuel economy, while meeting the most stringent emission standard SULEV as a full-size vehicle.

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.

Non-equilibrium all-atom MD simulations are used to study the traction properties of hydrocarbon fluids. A fluid layer is confined between two solid Fe plates under the constant normal force of 1.0 GPa. Traction simulations are performed by applying a relative sliding motion to the Fe plates. Shear behaviors of nine hydrocarbon fluids are simulated on a sufficiently large film thickness of 6.7 nm, and succeeded in reproducing the order of the experimental traction coefficients. The dynamic mechanism of the momentum transfer on layers of fluid molecules are analyzed focusing on the intermolecular interactions (density profile, orientation factor, pair-correlation function) and intramolecular interactions (intramolecular interaction energy, conformation change of alicyclic ring). In contrast to the case of n-hexane, which shows low traction due to a fragile chain-like interaction, other mechanisms are obtained in the high traction molecules of cyclohexane, dicyclohexyl and santotrac 50.

Diamond-like carbon (DLC) films are of significant interest for the automobile field, because they possess the potential to improve friction properties under various sliding conditions. Among the various DLC films, the authors focus on silicon-containing DLC (DLC-Si) films, which exhibit extremely low friction coefficient under dry sliding conditions in an ambient air atmosphere. The aim of this study is to examine the influence of silicon content in DLC-Si films on the friction property of the films, and to clarify the low friction mechanism of the films. The friction test was conducted under dry sliding conditions. It was found that the films have an exceedingly low friction coefficient (about 0.05) ranging in silicon content from 4 at% to 17 at%. In order to examine the low friction mechanism of the films, surface analyses were done on the wear surface of DLC-Si films slid against bearing steel.

In order to enhance the catalytic performance of the NOx Storage-Reduction Catalyst (NSR Catalyst), the sulfur tolerance of the NSR catalyst was improved by developing new support and NOx storage materials. The support material was developed by nano-particle mixing of ZrO2-TiO2 and Al2O3 in order to increase the Al2O3-TiO2 interface and to prevent the ZrO2-TiO2 phase from sintering. A Ba-Ti oxide composite material was also developed as a new NOx storage material containing highly dispersed Ba. It was confirmed that the sulfur tolerance and activity of the developed NSR catalyst are superior to that of the conventional one.

The effect of the chemical reactivity of diesel fuel on PM formation was investigated using a flow reactor and a shock tube. Reaction products from the flow-reactor pyrolysis of the three diesel fuels used for the engine tests in Part 1(1) (“Base”, “Improved” and Swedish “Class-1”) were analyzed by gas chromatography. At 850C, Swedish “Class-1” fuel was found to produce the most PM precursors such as benzene and toluene among the three fuels, even though it contains very low amounts of aromatics. The chemical analyses described in Part 1 revealed that “Class-1” contains a large amount of branched and cyclic structures in the saturated hydrocarbon portion of the fuel. These results suggest that the presence of such branched and ring structures can increase exhaust PM emissions.

The catalyst of the crystalline ceramics known as a perovskite-type oxide was designed and controlled at the atomic level in order to create a new function for self-regeneration of precious metals in a usage ambience without auxiliary treatment. We have already reported that a catalyst with Pd supported on the perovskite-type oxide has higher activity than a catalyst with Pd supported on alumina. It was also found that Pd supported on the perovskite catalyst is finely dispersed [1, 2 and 3] The object of this study was to investigate the mechanism of self-regeneration by using hyper-analytical facilities. XAFS analysis, at SPring-8 (8 GeV), revealed that Pd is in six-fold coordinations with oxygen in a perovskite crystal, which indicating that Pd occupies the B site of the unit formula of ABO3 in the perovskite crystal structure under oxidation atmosphere.

A new material recycling technology for crosslinked rubber was developed using the continuous reactive processing method. In this process of producing reclaimed rubber, breakage of crosslinking points in the crosslinked rubber occurs selectively under the controls of shear stress, reaction temperature, and internal pressure in a modular screw type reactor. Deodorization during the process has also become possible by a newly developed method. The reclaimed rubber obtained from rubber waste generated from both automobile manufacturing products and post-consumer products shows excellent mechanical properties applicable to new rubber compounds. Furthermore, an enhanced rubber recycling process for producing thermoplastic elastomer (TPE) based on rubber waste has been established. The obtained TPE exhibits highly recoverable rubber elasticity and mechanical properties comparable to commercial TPE.

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 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.

Fifty percent distillation temperature (T50) can be used as a warm-up driveability indicator for a hydrocarbon-type gasoline. MTBE-blended gasoline, however, provides poorer driveability than a hydrocarbon-type gasoline with the same T50. The purposes of this paper are to examine the reason for poor engine driveability caused by MTBE-blended gasolines, and to propose a new driveability indicator for gasolines including MTBE-blended gasolines. The static and dynamic evaporation characteristics of MTBE-blended gasolines such as the evaporation rate and the behavior of each component during evaporation were analyzed mainly by using Gas Chromatography/Mass Spectrometry. The results of the analysis show that the MTBE concentration in the vapor, evaporated at ambient temperature (e.g. 24°C), is higher than that in the original gasoline. Accordingly, the fuel vapor with enriched MTBE flows into the combustion chamber of an engine just after the throttle valve is opened.

The effect of GTL diesel fuel on organic materials used in fuel delivery systems of vehicles was investigated. Specimens made from 16 kinds of organic materials were immersed in GTL diesel fuels synthesized at Refinery-A and Refinery-B (referred to as GTL-A and GTL-B, respectively) and then subjected to tensile testing. The tensile test results revealed that elongation of the nylon sample immersed in GTL-A was extremely small, about 4% of that of untreated nylon. In the light of this finding, the GTL diesel fuels and nylons before and after immersion test were analyzed in detail using about 20 analysis methods to determine the cause for poor elongation. The following points were found. (1) GTL-A consisted of low molecular-weight paraffins. (2) GTL-A had low molecular-weight i-paraffins. (3) The nylon immersed in GTL-A contained low molecular-weight paraffins. (4) The paraffins in the nylon immersed in GTL-A were richer in i-paraffins than the original GTL-A.