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Exhaust and evaporative emissions systems have been developed to match the characteristics and usage of the Toyota THS II plug-in hybrid electric vehicle (PHEV). Based on the commercially available Prius, the Toyota PHEV features an additional external charging function, which allows it to be driven as an electric vehicle (EV) in urban areas, and as an hybrid electric vehicle (HEV) in high-speed/high-load and long-distance driving situations. To reduce exhaust emissions, the conventional catalyst warm up control has been enhanced to achieve emissions performance that satisfies California's Super Ultra Low Emissions Vehicle (SULEV) standards in every state of battery charge. In addition, a heat insulating fuel vapor containment system (FVS) has been developed using a plastic fuel tank based on the assumption that such a system can reduce the diffusion of vapor inside the fuel tank and the release of fuel vapor in to the atmosphere to the maximum possible extent.

This research developed a new measurement technology for thermal analysis of the heat radiation from a hybrid transaxle case surface to the air and improved the heat radiation performance. This heat flux measurement technology provides the method to measure heat flux without wiring of sensors. The method does not have effects of wiring on the temperature field and the flow field unlike the conventional methods. Therefore, multipoint measurement of heat flux on the case surface was enabled, and the distribution of heat flux was quantified. To measure heat flux, thermal resistances made of plastic plates were attached to the case surface and the infrared thermography was used for the temperature measurement. The preliminary examination was performed to confirm the accuracy of the thermal evaluation through heat flux measurement. The oil in the transaxle was heated and the amount of heat radiation from the case surface was measured.

This paper describes a new plastic coloring and forming system. The system greatly reduces the time and amount of raw materials necessary for color changes, and eliminates the need for manual cleaning during a color change. This system is well-suited for small-lot production with frequent color changes, as well as for automated production systems. The system is being used by auto parts makers, and is practical in a variety of other fields involved with the coloring and forming of plastics.

The impact of fatty acid methyl ester (FAME) blended diesel fuel on engine/vehicle systems was comprehensively investigated by vehicle, laboratory and engine tests. In this study, 20% FAME blended fuel (B20) was mainly used and soy bean oil methyl ester (SME) was primarily selected as the FAME. Vehicle testing with long-term fuel storage in vehicle fuel tanks was conducted, considering the most severe conditions in market use. Laboratory and engine tests were also conducted to better understand the vehicle test results. In the vehicle test, engine startability, idle roughness and fuel injection control were evaluated using nine vehicles with plastic or metal fuel tanks. All vehicles showed no problems up to 7 months. While five vehicles with plastic fuel tank did not show any problems throughout the test period up to 18 months, four vehicles with metal fuel tanks experienced malfunctions in engine start or fuel injection control following 8, 13, 13 and 18 months respectively.

This paper describes the application of a life prediction method for stainless steel exhaust manifolds. Examination of the exhaust manifold cracks indicated that many of the failures could be attributed to out-of-phase thermal fatigue due to compressive strains that occur at high temperatures. Therefore, the plastic strain range was used as the crack initiation criteria. In addition, the comparison of the calculated thermal fatigue stress-strain hysteresis to the experimental hysteresis made it clear that it was essential to use the stress-strain data that was obtained through tensile and compression testing by keeping the test specimens at the maximum temperature of the thermal fatigue test mode. A finite element crack prediction method was developed using the aforementioned material data and good results were obtained.

In order to clarify the diesel fuel spray characteristics inside the cylinder, we developed two novel techniques, which are preparation of same level of temperature and pressure ambient as inside cylinder and quantitative measurement of vapor concentration. The first one utilizes combustion-type constant-volume chamber (inner volume 110cc), which allows 5 MPa and 873K by igniting the pre-mixture (n-pentane and air) with two spark plugs. In the second technique, TMPD vapor concentration is measured by using Laser Induced Exciplex Fluorescence method (LIEF). The concentration is compensated by investigation of the influence of ambient pressure (from 3 to 5 MPa) and temperature (from 550 to 900 K) on TMPD fluorescence intensity. By using two techniques, we investigated the influence of nozzle hole diameter, injection pressure and ambient condition on spray characteristics.

Premixed diesel combustion modes including low temperature combustion and MK combustion are expected to realize smokeless and low NOx emissions. As ignition must be delayed until after the end of fuel injection to establish these combustion modes, methods for active ignition control are being actively pursued. It is reported that alcohols including methanol and ethanol strongly inhibit low temperature oxidation in HCCI combustion offering the possibility to control ignition with alcohol induction. In this research improvement of diesel combustion and emissions by ethanol intake port injection for the promotion of premixing of the in-cylinder injected diesel fuel, and by increased EGR for the reduction of combustion temperature.

In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

CARB (California Air Resources Board) has required the evaporative emissions to be restricted to 1/4th of the parameter stated in the 1995 regulations. Furthermore, hydrocarbons (hereafter, HC) from the fuel system must be reduced to near 0.0 grams, according to the PZEV (Partial Zero Emission Vehicle) regulations enforced from 2003. The wet film in intake ports and fuel leaking from the injector nozzles evaporate and diffuse while the car is parked, and consequently may cause HC to leak the air cleaner inlet. The air cleaner which prevents HC leakage from the air intake system is already in mass production. In the course of designing this product to be installed in a vehicle, the authors developed a method to estimate the amount of HC that reaches the air cleaner. Based on detailed investigation on HC distribution and the changes that occur during parking, the HC amount reaching the air cleaner was calculated by both the equation of diffusion and the equation of state.

A new stratified charge 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 and a shell-shaped piston cavity. This system, basically classified into the wall-guided mixture preparation concept that leads air/fuel mixture to the spark plug periphery by means of spray penetration and piston cavity configuration without an extra intake air flow controlling system, obtained wide engine operating area with stratified combustion and high output performance. This report presents the characteristics of stratified mixture formation and combustion, especially the important factor for achieving stable stratified combustion in the high-speed region, which have been clarified through analytical studies.

An experimental study was carried out in order to reduce engine-out HC emissions from a direct injection spark ignition (DISI) engine during the cold start period. The objectives of this study were to investigate the fuel behavior quantified with an analytic method and to propose some practical techniques to reduce the cylinder-wetting fuel volume and engine-out HC emissions. Compared to the MPI (Multi Port Fuel Injection) engine, required fuel volume for DISI engine was reduced during the cold start because intake port wall-wetting was not generated. On the other hand, a large volume of cylinder wetting fuel resulted in engine-out HC emissions. Injection timing, atomization and vaporization of injected fuel affected the cylinder-wetting fuel volume. Above all, Injection of the heated fuel provided good results. In summary, engine-out HC emissions from DISI engine was reduced compared to that of MPI engine during the cold-start period.

The Vapor Reducing Fuel Tank System (Bladder Tank System) using a flexible plastic membrane (Bladder Membrane) was newly developed in order to reduce the amount of vaporized gasoline in a steel fuel tank. This Bladder Membrane is flexible to expand in proportion to a fuel volume and prevents the permeation of the vaporized gasoline. As a result of our initial study for various materials, we decided to apply a multi-layer plastic material which could achieve both low fuel permeability and good flexibility. This multi-layer material consists of polyethylene(PE) for structural material and polyamide(PA) for low permeability. The modulus of the PE needs to achieve a sufficient flexibility in order to keep the movement of the membrane. While PA material must have not only low fuel permeability but also strong adhesion with the structural material of PE. We also clarify the membrane design to keep a good flexibility and to reduce a strain.

With the advance in modularization of engine parts in recent years, there is increased use of plastic-made products in air intake systems. Plastic-made intake manifolds (Fig. 1) provide many advantages including reduced weight, reduced cost, and lower intake air temperatures. However, these manifolds have one disadvantage when compared with conventional aluminum-made intake manifolds, in that they transmit more noise because of their lower material density. For example, plastic intake manifolds of early development often generate flow noise when the throttle is opened quickly. With conventional aluminum intake manifolds, this flow noise had generated, but was not heard. This flow noise is presumed to be generated because of high-speed airflow generated when the throttle is opened quickly, but the mechanism of this noise generation has not been clarified.

Methanol steam reforming, which is an endothermic reaction, needs some heating. Both methanol conversion ratio and carbon monoxide (CO) concentration increase when temperature is elevated. As CO poisons a typical polymer electrolyte of a fuel cell, the relationship between methanol conversion ratio and CO concentration is a trade-off one. It was found from preliminary researches that the reforming reaction speed is controlled by heat transfer rate at large methanol flow rate, where methanol conversion ratio becomes lower and CO concentration becomes higher. Therefore it is necessary to develop a new methanol reforming concept that provides stable combustion for heating and enhanced heat transfer for improving the trade-off relationship and making a compact reformer. Reforming catalyst using metal honeycomb support and a new catalytic combustion were applied to a new concept plate type methanol steam reformer, which is used in a fuel cell of 3 kW-class electric generation.

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.

ϵ-caprolactam was polymerized in the interlayer space of montmorillonite, the clay mineral yielding a nylon-clay hybrid (NCH). X-ray and TEM measurements revealed that each template of the silicate, which was 1 nm thick, was dispersed in the nylon 6 matrix, and that the interlayer distance of clay increased continuously from 1.2 nm for the unintercalated material to 21.4 nm for the intercalated material. Thus, NCH is a polymer-based molecular composite or a nano-composite. NCH contains 1-15 vol% of monolayer clay. Injection-molded NCH showed excellent mechanical properties compared with nylon 6 in terms of tensile strength, tensile modulus and heat resistance. The tensile modulus of NCH was twice that of Nylon 6, and the heat distortion temperature increased from 65°C for nylon 6 to 145°C for the NCH containing only 1.6 vol% of a clay mineral. It was found that such excellent properties of an NCH system was due to the strong ionic interaction between nylon 6 and the silicate layer.

The EMT (Elastomer Modified Thermoplastics) currently used in passenger car bumper fascia are limited in retaining low CLTE (Coefficient of Linear Thermal Expansion) and impact resistance, although they are highly rigid, which allows a reduction in weight, and also have high flowability during injection molding. We have developed a new bumper material called “Super Olefin Polymer” using a unique theory based upon a reversal of the current concept. The current polymer design concept of the EMT material is to compound and disperse the EPR (Ethylene Propylene Rubber) into the resin matrix such as polypropylene. We reversed the domain and the matrix, and treated the resin phase as the filler and the elastomer phase as the matrix.

A description is made of new control methods to improve response of wheel slip regulation. These methods enabled a new Traction Control (TRC) system based on throttle control rather than brake pressure to be developed. Major points are as follows: (1) Use of fuel injection cut-off to minimize delay (2) Additional adaptive throttle control logic By these means, a response nearly equal to that with brake pressure control is achieved at lower cost and with a considerable weight saving. Furthermore, the system, by suppressing noise and vibration, enhances the driver's control ability.

This research aimed to identify how combustion characteristics are affected by the addition of hydrogen to methane, which is the main components of natural gas, and to study a combustion method that takes advantage of the properties of the blended fuel. It was found that adding hydrogen did not achieve a thermal efficiency improvement effect under stoichiometric conditions because cooling loss increased. The same result was obtained under EGR stoichiometric conditions. In contrast, under lean burn conditions, higher thermal efficiency and lower NOx than with methane combustion was achieved by utilizing the wide flammability range of hydrogen to expand the lean limit. Although NOx can be decreased easily by the addition of large quantities of hydrogen, the substantially lower energy density of the fuel causes a substantial reduction in cruising range. Consequently, this research improved the combustion of a CNG engine by increasing the tumble ratio to 1.8.