Showing papers by "Toyota published in 2003"

Multifunctional Alloys Obtained via a Dislocation-Free Plastic Deformation Mechanism.

Abstract: We describe a group of alloys that exhibit “super” properties, such as ultralow elastic modulus, ultrahigh strength, super elasticity, and super plasticity, at room temperature and that show Elinvar and Invar behavior. These “super” properties are attributable to a dislocation-free plastic deformation mechanism. In cold-worked alloys, this mechanism forms elastic strain fields of hierarchical structure that range in size from the nanometer scale to several tens of micrometers. The resultant elastic strain energy leads to a number of enhanced material properties.

HCCI Combustion in DI Diesel Engine

Abstract: Ignition and combustion control of HCCI (Homogeneous Charge Compression Ignition) in DI (Direct Injection) Diesel Engine were examined. In this study, double injection technique was used by Common Rail injection system. The first injection was used as an early injection for fuel diffusion and to advance the changing of fuel to lower hydrocarbons (i.e. low temperature reaction). The second injection was used as an ignition trigger for all the fuel. It was found that the ignition of the premixed gas could be controlled by the second injection when the early injection was maintaining low temperature reaction. It was found that as the boost pressure increased, ignition timing advanced slightly and the rate of pressure increase markedly decreased. The rate of pressure increase is one of the factors concerning operation limit in this combustion. Therefore, the VNT (Variable Nozzle Turbo-charger) was applied to the production engine to allow boost pressure control. Spray characteristics and combustion analysis images were investigated by the shadowgraph method. Luminous flame was not observed. The fluctuation due to the low temperature reaction was observed from the shadowgraph images. Many ignition points appeared in the combustion chamber. Low NOx and smoke were possible both in the first injection and in the second injection by this combustion. This HCCI concept was named as UNIBUS (Uniform Bulky Combustion System) by the author et al. and applied to the production engine (1KD-FTV, 3 liter-4cylinder) in August 2000 in the Japanese market.

Oxygen Storage Materials for Automotive Catalysts: Ceria-Zirconia Solid Solutions

Abstract: This paper reviews progress in the development of oxygen storage materials for automotive exhaust catalysts. The research was mainly conducted as a study and development exercise in the author's laboratory in Japan. Ceria-lanthana solid solutions (CL) and the first generation of ceriazirconia solid solutions (CZ) were developed as excellent oxygen storage materials for automotive catalysts in the 1980s. These materials consist of ceria doped with less than 20 mol% of La4+ or Zr4+. An increase in oxygen defects in CL and CZ under reductive conditions is responsible for an enhanced oxygen storage capability on the cerium atoms. An accurate measure of the oxygen storage capacity (OSC) per cerium is very important for theoretical and practical treatments of the catalyst. The term “partial OSC” was introduced to describe this capacity and to differentiate it from the usual definition of the OSC, known also as the “total OSC”. After the development of CL and CZ, a new technology was developed to dissolve more than 20 mol% of zirconia in the ceria, allowing second generation CZ and third generation CZ (known as ACZ, which is doped with alumina) to be successfully developed in the 1990s. The partial OSC of these materials increases with increasing amounts of zirconia dissolved in the ceria, and also with decreasing material particle size after an engine durability test. In the case of ACZ, alumina was added to CZ based on the “diffusion barrier concept”, in which a diffusion barrier layer inhibits the coagulation of CZ and A when the material is required for duty at high temperature in air. Furthermore, the relationship between the total or partial OSC and the structure of the ceriazirconia solid solutions is explained in this paper. For ceriazirconia solid solutions composed of equimolar CeO2 and ZrO2(Ce/Zr=1), the total or partial OSC of the κ-phase CeZrO4, in which the cerium and zirconium ions are regularly distributed, was about twice as large as that of a ceriazirconia solid solution with a relatively irregular distribution of cerium and zirconium ions, and about five times larger than that of a mixture of ceria powder and zirconia containing only a small amount of ceriazirconia solid solution. It corresponds to about 89% of the theoretical maximum value. For a ceriazirconia solid solution composed of non-equimolar CeO2 and ZrO2(Ce/Zr ≠ 1), the partial OSC of a ceria-κ-phase solid solution with a zirconia content of between 30 and 50mol% is much higher than that of a ceriazirconia solid solution of the same zirconia content. The partial OSC of a κ-phase and zirconia mixed oxide, which is formed by reducing the material at 1200 °C, reaches a value above 0.20 mol-O2/mol-Ce (about 80% of the theoretical maximum value of the partial OSC), when the zirconia content is between 50 and 80 mol%. The Toyota Motor Corp. has put automotive three-way catalysts containing the first, second and third generations of CZ into practical use on a global basis.

A Computer Simulation Study of the Mesoscopic Structure of the Polyelectrolyte Membrane Nafion

Abstract: We studied the mesoscopic structure of the perfluorinated sulfonic acid membrane Nafion containing water using a dissipative particle dynamics (DPD) simulation. A Nafion polymer is modeled by connecting coarse-grained particles, which correspond to the hydrophobic backbone of polytetrafluoroethylene and perfluorinated side chains terminated by hydrophilic end particles of sulfonic acid groups. Water is also modeled by the same size particle as adopted in the Nafion model, corresponding to a group of four H2O molecules. The Flory–Huggins χ-parameters between DPD particles are estimated from the mixing energy calculation using an atomistic simulation. In the DPD simulation, water particles and hydrophilic particles of Nafion side chains spontaneously form aggregates and are embedded in the hydrophobic phase of the Nafion backbone. This structure is a bicontinuous phase of Nafion and water regions and has a continuous path in the cavity of water in any direction. Although this sponge-like structure is essentially identical to the cluster-network model proposed from the experimental studies, the shape of the water clusters is not spherical but irregular, and the water regions are indistinguishable structures of water clusters and their channels. The cluster size and its dependence on the water content are in good agreement with experimental reports; therefore, the simulated mesoscopic structure is confirmed to be a highly possible one.

Particle size control of mono-dispersed super-microporous silica spheres

Abstract: The particle size of mono-dispersed super-microporous silica spheres synthesized from tetramethoxysilane and n-decyltrimethylammonium bromide was successfully controlled by variation of the synthesis temperature, methanol ∶ water ratio in solvent and silica source in the range of 0.52 to 1.25 µm, while their mono-dispersion characteristics were retained. The adsorption properties of the samples were a specific surface area of 700–1000 m2 g−1 and a pore volume of 0.32–0.41 ml g−1, and were mainly affected by the synthesis temperature. The mono-dispersed super-microporous silica spheres obtained had a particle diameter equivalent to the wavelength of visible light, and thus their optical use, for example, as photonic crystals, is expected.

Voltage converter control apparatus, and method

Abstract: By using a target voltage Vc* of a capacitor connected to the output side of a DC/DC converter and a voltage Vb of a battery connected to the input side of the DC/DC converter, a duty ratio D as a drive instruction of the DC/DC converter is calculated. By using the voltage Vb, the electromotive force Vbo of the battery, and the charge/discharge current Ib of the battery, an internal resistance Rb is calculated. According to the internal resistance Rb and the electromotive force Vbo, the current value when the battery output becomes maximum is set as the upper limit value of the optimal current range IR, the DC/DC converter is driven/controlled by limiting the duty ratio D so that the current Ib is within the range of the optimal current range IR. Thus, it is possible to appropriately convert the battery input voltage.

Thermoelectric performance of Bi- and Na-substituted Ca3Co4O9 improved through ceramic texturing

Abstract: Plate-like particles of Ca3Co4O9 have been prepared in which Bi and Na were partially substituted for Ca to improve the thermoelectric performance. Successfully fabricated dense and highly textured ceramics have been obtained by combining the templated grain growth technique (TGG) with hot-pressing (HP). Ca3Co4O9 single crystals, which have alternating layers of Co–O and Ca–Co–O in the direction of the c-axis, show high electrical conductivity along the layer compared with that across the layer. Hence, a highly oriented TGG + HP specimen showed high electrical conductivity compared with the specimen sintered under uniaxial pressure (UP + PLS). The improved electrical conductivity with high Seebeck coefficient of the highly oriented specimen (TGG + HP) gave a high thermoelectric power factor of 5.9 × 10−4 W m−1 K−2 at 1073 K. The figures-of-merit at 773 K and 1073 K were calculated to be 8.54 × 10−5 K−1 (ZT = 0.066 at 773 K) and 1.69 × 10−4 K−1 (ZT = 0.18 at 1073 K), respectively. These values are quite high among Ca–Co–O polycrystalline systems reported so far.

Vapor phase hydrogenation of phenol over palladium supported on mesoporous CeO2 and ZrO2

Abstract: Mesoporous CeO 2 and ZrO 2 were synthesized using hexadecyltrimethyl ammonium bromide (C 16 TMABr) as the template. Their physicochemical properties were investigated using X-ray diffraction (XRD) and N 2 adsorption–desorption methods. Palladium (Pd) 1–10 wt.% was loaded on the mesoporous CeO 2 and ZrO 2 by deposition–precipitation method. The Pd metal surface area, dispersion and crystallite sizes were determined by room temperature H 2 chemisorption on reduced samples. The catalytic activity of Pd supported mesoporous CeO 2 (Pd/CeO 2 -MS) and ZrO 2 (Pd/ZrO 2 -MS) were evaluated for the first time in the vapor phase hydrogenation of phenol in the temperature range between 160 and 230 °C at atmospheric pressure. The reaction over 3% Pd/CeO 2 -MS at 180 °C offered cyclohexanone as the major product (about 50%) along with some amounts of cyclohexanol (about 35%) and cyclohexane (about 15%). The influences of Pd loading, temperature, H 2 /phenol ratio, contact time, and nature of solvent on the catalytic performance were investigated systematically. A 3% Pd/ZrO 2 -MS offered slightly lower phenol conversion but very high selectivity of cyclohexanone (above 90%). The Pd/CeO 2 -MS exhibited a stable activity, while Pd/ZrO 2 -MS underwent deactivation during on-stream operation. Under similar operating conditions, the catalytic performance of Pd/CeO 2 -MS and Pd/ZrO 2 -MS was found to be far better than that obtained using MgO, Al 2 O 3 and MgO-Al 2 O 3 derived from hydrotalcites (MgAl-CHT) as supports. The benefit of using mesoporous oxide support to Pd was also demonstrated by comparing the catalytic activity with the activities of commercial oxide supports.

Speech recognition system having multiple speech recognizers

Abstract: A speech recognition system recognizes an input speech signal by using a first speech recognizer and a second speech recognizer each coupled to a decision module. Each of the first and second speech recognizers outputs first and second recognized speech texts and first and second associated confidence scores, respectively, and the decision module selects either the first or the second speech text depending upon which of the first or second confidence score is higher. The decision module may also adjust the first and second confidence scores to generate first and second adjusted confidence scores, respectively, and select either the first or second speech text depending upon which of the first or second adjusted confidence scores is higher. The first and second confidence scores may be adjusted based upon the location of a speaker, the identity or accent of the speaker, the context of the speech, and the like.

Budding and fission dynamics of two-component vesicles

Abstract: We studied the shape deformation induced by the phase separation of two-component vesicles using a dissipative particle dynamics simulation. Two types of amphiphiles, which have the same architecture but segregate from each other, are modeled by connecting particles representing the hydrophilic head and hydrophobic tail groups. After vesicle formation using a single component system, some of the amphiphiles are replaced by a second component, and then phase separation on the vesicle is simulated. Under appropriate conditions, typical shape deformations of a vesicle, such as crenated and invaginated shapes, are observed. We demonstrate that the budding and the fission are facilitated by lateral phase separation upon vesicle coupling to an asymmetric transversal distribution of amphiphiles in the bilayer. Moreover, simulations show a possible new pathway for the fission process triggered by cleavage along the domain boundary. Mesoscopic simulation based on a simple coarse-graining model reveals the dynamics of amphiphiles in vesicles that is essentially unpredictable using a conventional continuum model or full atomistic simulation.

Evaporated fuel treatment device for internal combustion engine

Abstract: A sealing valve is installed between a fuel tank and a canister. A purge VSV is installed between the canister and an intake path. A pump module unit is installed to introduce a negative pressure into the canister. The negative pressure is introduced into the canister while the purge VSV and sealing valve are closed. An open failure diagnostic check is conducted on the sealing valve in accordance with the prevalent canister side pressure. A close failure diagnostic check is conducted on the sealing valve by making use of a differential pressure that is generated across the sealing valve as a result of the open failure diagnostic check.

Steering apparatus for a vehicle

Abstract: A steering apparatus of a vehicle can achieve detection of an absolute angle of a steering shaft with a simple structure while preventing an increase in power consumption. A resolver sensor outputs an output signal corresponding to an angular position of a steering shaft of the vehicle. A lock mechanism restricts rotation of the steering shaft at locking positions provided around the steering shaft at equal intervals. An axial multiplication angle k× of the output signal of the resolver sensor and a number N of the locking positions provided around the steering shaft satisfy a relationship represented by k≦N.

Making plastics from garbage : a novel process for poly-L-lactate production from municipal food waste

Abstract: Summary We propose a novel recycling system for municipal food waste that combines fermentation and chemical processes to produce high-quality poly-L-lactate (PLLA) biodegradable plastics. The process consists of removal of endogenous D, L-lactic acid from minced food waste by a propionibacterium, L-lactic acid fermentation under semisolid conditions, L-lactic acid purification via butyl esterification, and L-lactic acid polymerization via LL-lactide. The total design of the process enables a high yield of PLLA with high optical activity (i.e., a high proportion of optical isomers) and novel recycling of all materials produced at each step, with energy savings and minimal emissions. Approximately 50% of the total carbon was removed, mostly as L-lactic acid, and 100 kg of collected food waste yielded 7.0 kg PLLA (about 34% of the total carbon). The physical properties of the PLLA yielded in this manner were comparable to those of PLLA generated from commercially available. L-lactic acid. Evaluation of the process is also discussed from the viewpoints of material and energy balances and environmental impact.

Transcriptome analysis of O3-exposed Arabidopsis reveals that multiple signal pathways act mutually antagonistically to induce gene expression.

Abstract: To analyze cellular responses to ozone (O3), we performed a large-scale analysis of the Arabidopsis transcriptome after plants were exposed to O3 for 12 h. By using cDNA macroarray technology, we identified 205 non-redundant expressed sequence tags (ESTs) that were regulated by O3. Of these, 157 were induced and 48 were suppressed by O3. A substantial proportion of these ESTs had predicted functions in cell rescue/defense processes. Using these isolated ESTs, we also undertook a comprehensive investigation of how three hormones, ethylene (ET), jasmonic acid (JA), and salicylic acid (SA), interact to regulate O3-induced genes in various genetic backgrounds of Arabidopsis, such as the ET-insensitive ein2-1, JA-resistant jar1-1, and SA-insensitive npr1-1. The expression of half of the 157 induced genes, especially cell rescue/defense genes, was controlled by ET and JA signaling, indicating that O3-induced defense gene expression at this stage was mainly regulated by ET and JA. Clustering analysis of the 157 O3-induced gene expressions revealed that multiple signal pathways act mutually antagonistically to induce the expression of these genes, and many cell rescue/defense genes induced by ET and JA signal pathways were suppressed by SA signaling, suggesting that the SA pathway acts as a strong antagonist to gene expression induced by ET and JA signaling.

Preparation and properties of polyethylene‐clay hybrids

Abstract: Polyethylene-clay hybrids have been prepared successfully by melt compounding with maleic anhydride grafted polyethylene (MA-g-PE), organophilic clay and polyethylene. In these polyethylene-clay hybrids, the silicate layers of the clay were exfoliated and dispersed to the monolayers. The hybrids exhibit higher tensile yield strengths and tensile moduli than those of polyethylene matrices and those of polyethylene-inorganic clay composites. When the 5-wt% clays were loaded, the tensile yield strength and the tensile modulus of the hybrid were, respectively, 1.4 and 1.8 times higher than those of the polyethylene/MA-g-PE mixture. The gas permeability of that clay hybrid decreased 30% compared with polyethylene/MA-g-PE mixture.

Biorefinery

Abstract: The biorefinery produces fuels, solvents, plastics and food for human beings. In some countries, these biorefinery products are made from waste biomass. The main processes in the biorefinery involve ethanol fermentation and lactic acid fermentation. For the biorefinery, many hybrid technologies were developed from different fields, such as bioengineering, polymer chemistry, food science and agriculture.

Rapid Detection of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum Organisms in Genitourinary Samples by PCR-Microtiter Plate Hybridization Assay

Abstract: We present a method for detecting the presence of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum organisms, which are thought to be associated with nongonococcal urethritis (NGU) and other genitourinary infections, in clinical samples. This method consists of PCR amplification of a part of the 16S rRNA gene followed by 96-well microtiter plate hybridization assay using four species-specific capture probes to detect the targets. To test the efficacy of this method, we applied it to the detection of the four species in the urine of patients with NGU. There were no cross-reactions with other human mycoplasmas or ureaplasmas, and the PCR-microtiter plate hybridization assay detected as few as 10 copies of the 16S rRNA gene of each of the four species. Based on these results, this PCR-microtiter plate hybridization assay can be considered an effective tool for the diagnosis of genitourinary infections with mycoplasmas or ureaplasmas.

Microstructure and Thermal Properties of Polylactides with Different L- and D-Unit Sequences: Importance of the Helical Nature of the L-Sequenced Segments

Abstract: A series of polylactides (PLA) with different stereo sequences are prepared by the copolymerization of L-lactide and DL-lactide. It is confirmed that the glass transition temperature (Tg) of the PLA decreases with decreasing optical purity of the lactate units (%ee) according to the Fox's equation. Analysis of the FT-IR spectra of these PLA samples reveals that the absorbance at 1 265 cm−1 (δCH + νCOC) decreases with increasing L-content while the absorbance at 1 210 cm−1 (νasCOC + rasCH3) increases with increasing L-content. These changes in absorbance are reasonably correlated with the randomness and helical nature of the L-sequenced segments involved in PLA. Namely, the PLA chains with higher L-content comprise a higher number of short helical blocks that are made of several L-lactate units. This difference in helical nature causes the opposite dependences of Tg and density on the L-content of PLA; i.e., the increased Tg and decreased density with increasing L-content. FT-IR spectra of a PDLLA film, NO-PLLA, and BO-PLLA.

Exhaust emission control device

Abstract: PROBLEM TO BE SOLVED: To provide an exhaust emission control device, for properly cleaning exhausted harmful components even in an internal combustion engine or a combustion chamber operated mainly under an excess air condition, for properly eliminating nitrogen oxides in exhaust gas or particulate matters such as soot, and for maintaining its cleaning ability. SOLUTION: The exhaust emission control device comprises: nitrogen oxide adsorbent 4 disposed to an exhaust passage of the internal combustion engine 1 to temporally adsorb the nitrogen oxides and desorb the adsorbed nitrogen oxides by temperature rise or in a reduction atmosphere; an adsorbed material desorbing means 3 disposed upstream in exhaust flow of the nitrogen oxide adsorbent 4 to rise the temperature of the exhaust or air, or to make it be in the reduction atmosphere; a combustion device 5 disposed downstream in exhaust flow of the nitrogen oxide adsorbent 4 and including an air supply means 15, a fuel supply means 6, and an ignition means 7; and a filter device 40 disposed downstream in exhaust flow of the combustion device 5 to trap particulate matters contained in the exhaust gas. COPYRIGHT: (C)2007,JPO&INPIT