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For reduction of fuel consumption, a new device “Water Jacket Spacer” which improves temperature distribution of a cylinder block bore wall was developed. In the case of a conventional cylinder block, coolant flow concentrates at the bottom and middle region of the water jacket. While temperature of the upper bore wall is high (due to high-temperature combustion gas) the temperature of the lower bore wall is low, since its only function is to support the piston. When the developed spacer is inserted into a water jacket, the coolant flow concentrates at the upper part of the jacket. As a result, cooling ability to the upper bore wall was improved and temperature of lower bore wall was increased, thereby reducing fuel consumption.

Trivalent chromate coating is replacing the conventional hexavalent chromate coating applied on zinc plating. Zinc plating uses one of three types of plating baths (zincate, cyanide and chloride) according to the characteristics required of subject parts. It has been recognized that trivalent chromate coating provides different corrosion resistance depending on the type of zinc plating bath used. Zinc plating with chromate coating were analyzed to clarify the cause of the corrosion resistance variation with the type of zinc plating bath. It has been revealed that the chromate coating thickness and the condition of top SiO2 layer vary with the type of zinc plating bath, resulting in corrosion resistance variation.

Phosphor thermometry was used during fuel injection in an optical engine with the glass piston of reentrant type. SiO2 coated phosphor particle was used for the gas-phase temperature measurements, which gave much less background signal. The measurements were performed in motored mode, in combustion mode with injection of n-heptane and in non-combustion mode with injection of iso-octane. In the beginning of injection period, the mean temperature of each injection cases was lower than that of the motored case, and temperature of iso-octane injection cases was even lower than that of n-heptane injection cases. This indicates, even if vaporization effect seemed to be the same at both injection cases, the effect of temperature decrease changed due to the chemical reaction effect for the n-heptane cases. Chemical reaction seems to be initiated outside of the fuel liquid spray and the position was moving towards the fuel rich area as the time proceeds.

1 Recently, demand for small-bore compact vehicle engines has been increasing from the standpoint of further reducing CO2 emissions. The generalization and formulation of combustion processes, including those related to emissions formation, based on a certain similarity of physical phenomena regardless of engine size, would be extremely beneficial for the unification of development processes for various sizes of engines. The objective of this study is to clarify what constraints are necessary for engine/nozzle specifications and injection conditions to achieve the same combustion characteristics (such as heat release rate and emissions) in diesel engines with different bore sizes.

In an evaluation of crashworthiness for the cars made of aluminum alloys, the evaluation considering fracture phenomenon comes to be needed because conventional aluminum alloys have low fracture strain (10-20%). In case of the development of a B-Pillar made by die cast, if crack occurrence, furthermore, separation of a part can be estimated by using CAE in crashworthiness evaluations, we can reduce the number of prototype makings and the cost of development using expensive dies. Therefore, we performed crashworthiness evaluations by CAE using some sort of a damage & fracture material model. It is known as “Orthotropic damage & fracture model”.

In order to achieve good adhesive properties, typical decorative plastic plating technology uses a chromic acid process that creates an anchor effect. Due to environmental concerns with hexavalent chromium, there is a need to find alternative processes. Pretreatment using highly concentrated ozonized water was investigated as a novel approach to achieving this goal. In the conventional chromic acid process, strong adhesion between plating membranes is achieved by roughing the ABS (acrylonitrile-butadiene-styrene) resin surface by approximately 1 um. On the other hand, the highly concentrated ozonized water process achieves good adhesion with a smooth resin by changing the resin from ABS to ASA (acrylate-styrene-acrylonitrile). It was discovered that the difference in this strength of adhesion was the difference in resin surface strength (existence of deterioration or otherwise).

In the 1st generation Toyota "MIRAI" fuel cell stack, carbon protective surface coating is deposited after individual Ti bipolar plate being press-formed into the desired shape. Such a process has relatively low production speed, not ideal for large scale manufacturing. A new coating concept, consisting of a nanostructured composite layer of titanium oxide and carbon particles, was devised to enable the incorporation of both the surface treatment and the press processes into the roll-to-roll production line. The initial coating showed higher than expected contact resistance, of which the root cause was identified as nitrogen contamination during the annealing step that inhibited the formation of the composite film structure. Upon the implementation of a vacuum furnace chamber as the countermeasure, the issue was resolved, and the improved coating could meet all the requirements of productivity, conductivity, and durability for use in the newer generation of fuel cell stacks.

Small bore diesel engines often adopt a two-valve cylinder head and a non-central injector layout to expand the port flow passage area. This non-central injector layout causes asymmetrical gas flow and fuel distribution, resulting in worse heat losses and a less homogenous fuel-air mixture than an equivalent four-valve cylinder head layout with a central injector. This paper describes the improvement of piston bowl geometry to achieve a more homogeneous gas flow and fuel-air mixture. This concept reduced fuel consumption by 2.5% compared to the original piston bowl geometry, while also reducing NOx emissions by 10%.

The quantity of heavy components in fuel is increasing as automotive fuels diversify, and engine oil formulations are becoming more complex. These trends result in the formation of larger amounts of carbon deposits as reaction byproducts during combustion, potentially worsening the susceptibility of the engine to knock [1]. The research described in this paper aimed to identify the mechanism that causes knocking to deteriorate due to carbon deposits in low to medium engine load ranges, which are mainly used when the vehicle drives off and accelerates. With this objective, the cylinder temperature and pressure with and without deposits were measured, and it was found that knocking deteriorates in a certain range of ignition timing.

We have tried to improve damping capacity of an aluminum alloy by means of dispersing ceramic particles (low damping SiC and high damping NdNbO4) of different sizes and volume fractions in the aluminum alloy by powder metallurgy. It is shown that the damping capacity is increased in every case accompanying an increase of Young's modulus. It is also shown that the intrinsic damping capacity of dispersed particles does not play a role in improving the damping capacity. The increase of the damping capacity seems to be attributed to dislocations breakaway, interaction of fine particles and dislocations, and relaxation of interface between ceramic particles and aluminum matrix.

The reduction of the heat loss from the in-cylinder gas to the combustion chamber wall is one of the key technologies for improving the thermal efficiency of internal combustion engines. This paper describes an experimental verification of the “temperature swing” insulation concept, whereby the surface temperature of the combustion chamber wall follows that of the transient gas. First, we focus on the development of “temperature swing” insulation materials and structures with the thermo-physical properties of low thermal conductivity and low volumetric heat capacity. Heat flux measurements for the developed insulation coating show that a new insulation material formed from silica-reinforced porous anodized aluminum (SiRPA) offers both heat-rejecting properties and reliability in an internal combustion engine. Furthermore, a laser-induced phosphorescence technique was used to verify the temporal changes in the surface temperature of the developed insulation coating.

Recently, engines achieving high power levels are becoming increasingly common. The trend is toward increasing the inflow of lubricating oil into the crankcase through several factors (for example, increasing the flow rate of the cooling oil jets in order to reduce the thermal load of the pistons). In addition, the mechanical losses induced by the motion of the crankshaft and connecting rods through the additional oil are intensified due to the higher engine speeds at maximum power. In this article, we confirmed a method of separating the pumping loss and the agitation loss by measuring the pressure in the crankcase and an empirical formula was found for predicting pumping loss from displacement and ventilating area. We also investigated the effect of reducing the lubrication oil flow rate, as well as other factors affecting the oil flow, on the mechanical loss at high engine speeds.

A technique for induction-hardening local portions of vehicle body reinforcements press-formed of thin sheet steel has been developed, with the aim of ensuring occupant safety in a side collision. This technique for increasing the tensile strength of sheet steel was practically applied to the front floor cross member and center pillar reinforcement. Owing to this method, the weight of body reinforcements can be decreased. New induction-hardening systems have also been developed for the present technique. One is an apparatus which allows induction-hardening a part with a three-dimensionally curved surface. Another is a straightening quench technique used to retain the same dimensional accuracy as the original press-formed part.

From the viewpoint of measures for environmental issues, the amount of solvents in paint for aluminum wheels needs to be minimized. Environmentally friendly powder coatings have been used widely for primer coating and clear coating, but there is no precedent for its use for base coating. This time, we optimized the condition of surface treatment of pigment and hardening behavior of constituent resin in the melting process and succeeded in developing a metallic powder coating for aluminum wheels that fulfills the appearance and the quality requirements of aluminum wheels.

Small bore diesel engines often adopt a two-valve cylinder head and a non-central injector layout to expand the port flow passage area. This non-central injector layout causes asymmetrical gas flow and fuel distribution, resulting in worse heat losseses and a less homogenous fuel-air mixture than an equivalent four-valve cylinder head layout with a central injector. To improve these problems Toyota applied a new concept which was characterized by tapered shape design on the upper portion of the piston and low compression ratio to achieve more homogeneous gas flow and fuel-air mixture. This paper describes the impact of new combustion concept and the mechanism of the improvement by 3D-CFD analysis and optical measurement.

The experimental research vehicle ES3 body was realized by using various aluminum-joining technologies: MIG welding, laser welding, self-piercing riveting. These technologies were applied selectively to make full use of their individual characteristics, according to the body structure and joined materials. Of these technologies, self-piercing riveting is advantageous in several respects. Aiming to expand the application range of riveting technology, we developed a die that prevents cracks in joining aluminum casting, and a method to improve rivet driving in thick, multi-pile portion. We further studied the feasibility of aluminum rivets. This paper outlines the ES3 body structure and it's joining technologies used and introduces the further improvements we developed concerning self-piercing riveting.

Crosscheck tests of fast electrical mobility spectrometers, Differential Mobility Spectroscopy (DMS) and Engine Exhaust Particle Sizer(EEPS), were conducted to evaluate the accuracy of fine particle measurement. Two kinds of particles were used as test particles for the crosscheck test of instruments: particles emitted from diesel vehicles and diluted in a full dilution tunnel, and particles generated by CAST. In the steady state tests, it was confirmed that the average concentration of each instrument was within the range of ±2σ from the average concentration of all the same type of instruments. In the transient tests, it is verified that the instruments have almost equal sensitivity. For application of the fast electrical mobility spectrometers to evaluation of particle number and size distributions, it is essential to develop a calibration method using reference particle counters and sizers (CPC, SMPS, etc.) and maintenance methods appropriate for each model.

Abnormal combustion referred to as Low Speed Pre-Ignition (LSPI) may restrict low speed torque improvements in turbocharged Direct Injection (DI) - Spark Ignition (SI) Engines. Recent investigations have reported that the auto-ignition of an engine oil droplet from the piston crevice in the combustion chamber may cause unexpected and random LSPI. This study shows that engine oil formulations have significant effects on LSPI. We found that the spontaneous ignition temperature of engine oil, as determined using High-Pressure Differential Scanning Calorimetry (HP-DSC) correlates with LSPI frequency in a prototype turbocharged DI-SI engine. Based on these findings, we believe that the oxidation reaction of the oil is very important factor to the LSPI. Our test data, using a prototype engine, shows both preventative and contributory effects of base oil and metal-based engine oil additives.

Fluoroelastmers are well known for their resistance to heat and fluids, and have become major material for crankcase oil seals. On the other hand, new additive formulations are developed for engine lubricants used for fuel economic gasoline engines. In this paper, the effects of those additives on properties of fluoroelastmers are investigated. The results of the immersion tests of both test plaques and oil seal products indicate that dithiocarbamates, friction modifier, have hardening effects on fluoroelastmers. The fluoroelastmer deterioration mechanism is determined by analysis of elastmer samples after immersion in oil.

To evaluate the influence of FAME, which has poor oxidation stability, on engine oil performance, an engine test was conducted under large volumes of fuel dilution by post-injection. The test showed that detergent consumption and polymerization of FAME were accelerated in engine oil, causing a severe deterioration in piston cleanliness and sludge protection performance of engine oil.