DRASTIC IMPROVEMENT OF THERMAL EFFICIENCY BY RAPID PISTON-MOVEMENT NEAR TDC

Moriyoshi, Y.,Sano, M.,Morikawa, K.,Kaneko, M. The Korean Society of Automotive Engineers 2006 International journal of automotive technology Vol.7 No.3

A new combustion method of high compression ratio SI engine was studied and proposed in order to achieve high thermal efficiency, comparable to that of CI engine. Compression ratio of SI engine is generally restricted by the knocking phenomena. A combustion chamber profile and a cranking mechanism were studied to avoid knocking with high compression ratio. Because reducing the end-gas temperature will suppress knocking, a combustion chamber was considered to have a wide surface at the end-gas region. However, wide surface will lead to large heat loss, which may cancel the gain of higher compression ratio operation. Thereby, a special cranking mechanism was adapted which allowed the piston to move rapidly near TDC. Numerical simulations were performed to optimize the cranking mechanism for achieving high thermal efficiency. An elliptic gear system and a leaf-shape gear system were employed in numerical simulations. Livengood-Wu integral, which is widely used to judge knocking occurrence, was calculated to verify the effect for the new concept. As a result, this concept can be operated at compression ratio of fourteen using a regular gasoline. A new single cylinder engine with compression ratio of twelve and TGV(Tumble Generation Valve) to enhance the turbulence and combustion speed was designed and built for proving its performance. The test results verified the predictions. Thermal efficiency was improve over 10% with compression ratio of twelve compared to an original engine with compression ratio of ten when strong turbulence was generated using TGV, leading to a fast combustion speed and reduced heat loss.

Charge Density Distributions in Bi4Ti3O12 and Bi3.25La0.75Ti3O12 in the Paraelectric Phase

Chikako Moriyoshi,Sayaka Kimura,Yoshihiro Kuroiwa,김수재,Yuji Noguchi 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

The electron charge density distributions of the bismuth layered ferroelectric materials Bi4Ti3O12 (BiT) and Bi3.25La0.75Ti3O12 (BLT) in the paraelectric phase are demonstrated by analyzing the high-energy synchrotron-radiation powder-diffraction data on the basis of the maximum entropy method (MEM)/Rietveld method. The crystal structures of BiT and BLT are quite similar, and no significant difference is observed in the chemical bonding nature in the paraelectric phase. This result differs from the experimental fact that, in the ferroelectric phase, electron orbital hybridization between Bi and O in the perovskite layer is formed along the a-axis in BiT while the hybridization between Bi/La and O is revealed not only along the a-axis but also along the b-axis in BLT. We attribute the unchanged Curie temperatures for the Bi4−xLaxTi3O12 system to the same crystal structures, including the chemical bonding nature, in the paraelectric phase. The electron charge density distributions of the bismuth layered ferroelectric materials Bi4Ti3O12 (BiT) and Bi3.25La0.75Ti3O12 (BLT) in the paraelectric phase are demonstrated by analyzing the high-energy synchrotron-radiation powder-diffraction data on the basis of the maximum entropy method (MEM)/Rietveld method. The crystal structures of BiT and BLT are quite similar, and no significant difference is observed in the chemical bonding nature in the paraelectric phase. This result differs from the experimental fact that, in the ferroelectric phase, electron orbital hybridization between Bi and O in the perovskite layer is formed along the a-axis in BiT while the hybridization between Bi/La and O is revealed not only along the a-axis but also along the b-axis in BLT. We attribute the unchanged Curie temperatures for the Bi4−xLaxTi3O12 system to the same crystal structures, including the chemical bonding nature, in the paraelectric phase.

Development of a Spray Model for Swirl-Type Gasoline DI Injectors

Yasuo Moriyoshi,Masahide Takagi,Xiao Hu 한국자동차공학회 2001 한국자동차공학회 Symposium Vol.- No.-

Prediction of the mixture formation process inside a gasoline DI engine is strongly required to improve both the fuel consumption rate and the exhaust gas emissions. A swirl-type injector, widely used for a gasoline DI engine, is characterized with drastic changes of the cone angle caused by ambient pressure. Numerical simulations of a free spray formed by a swirl-type injector have been carried out on the basis of a method of DDM (Discrete Droplet Model). In this study, firstly the ambiguity how to give the initial conditions is discussed. Secondly, the droplet deformation calculated by a breakup model was incorporated into the drag force tenn to take the influence of the drag variation into account. As a result. by performing optimizations of the initial conditions, the breakup models and the drag force model, spray characteristics of a swirl-type injector were predicted quantitatively.<br/> <br/>

Spray Modeling of Fuel Injectors for Automotive Engines

( Yasuo Moriyoshi ) 한국액체미립화학회 2003 한국액체미립화학회 학술강연회 논문집 Vol.2003 No.-

DRASTIC IMPROVEMENT OF THERMAL EFFICIENCY BY RAPID PISTON-MOVEMENT NEAR TDC

Y. MORIYOSHI,M. SANO,K. MORIKAWA,M. KANEKO 한국자동차공학회 2006 International journal of automotive technology Vol.7 No.3

A new combustion method of high compression ratio SI engine was studied and proposed in order to achieve high thermal efficiency, comparable to that of CI engine. Compression ratio of SI engine is generally restricted by the knocking phenomena. A combustion chamber profile and a cranking mechanism were studied to avoid knocking with high compression ratio. Because reducing the end-gas temperature will suppress knocking, a combustion chamber was considered to have a wide surface at the end-gas region. However, wide surface will lead to large heat loss, which may cancel the gain of higher compression ratio operation. Thereby, a special cranking mechanism was adapted which allowed the piston to move rapidly near TDC. Numerical simulations were performed to optimize the cranking mechanism for achieving high thermal efficiency. An elliptic gear system and a leaf-shape gear system were employed in numerical simulations. Livengood-Wu integral, which is widely used to judge knocking occurrence, was calculated to verify the effect for the new concept. As a result, this concept can be operated at compression ratio of fourteen using a regular gasoline. A new single cylinder engine with compression ratio of twelve and TGV (Tumble Generation Valve) to enhance the turbulence and combustion speed was designed and built for proving its performance. The test results verified the predictions. Thermal efficiency was improve over 10% with compression ratio of twelve compared to an original engine with compression ratio of ten when strong turbulence was generated using TGV, leading to a fast combustion speed and reduced heat loss.

Analysis of Mixture Formation and Combustion Process in a DISC Engine

Yasuo, Moriyoshi 경상대학교 공과대학 항공기계공학부 1999 WORKSHOP 자료집 Vol.1999 No.1

In this report, the author has, briefly introduced research summary on the stratified charge combustion system that has a possibility of simultaneous reduction of exhaust emissions and fuel' consumption rate. Firstly, the effect of spatial distribution of mixture stratification on combustion characteristics was investigated using a constant volume chamber. Secondly, the break-up process of fuel spray was examined to control the mixture formation process. Thirdly, turbulence and combustion modeling was discussed as a tool to clarify the physical phenomena. Finally, a model GDI engine was employed to evaluate a new concept.

Adaptive Genetic Algorithm Observer and its Application to a Trailer Truck Control System

Hiroshi Kinjo,Moriyoshi Maeshiro,Eiho Uezato,Tetsuhiko Yamamoto 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Origin of Ultrahigh Dielectric Constants for Barium Titanate Nanoparticles

Satoshi Wada,C Moriyoshi,H. Yasuno,K Kakemoto,K Takizawa,M Ohishi,T Hoshina,T Tsurumi,Y Kuroiwa 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.2I

Barium titanate (BaTiO3) nanoparticles with various particle sizes from 17 to 1,000 nm were prepared by using the 2-step thermal decomposition method of barium titanyl oxalate under various degree of vacuum. Various characterizations revealed that these particles were impurity-free, defectfree, dense BaTiO3 nanoparticles. When the degree of vacuum was high (pressure of 150 Pa at 650 C), the dielectric constant of BaTiO3 particles with a size of around 60 nm exhibited a maximum of around 15,000. On the other hand, when the degree of vacuum was low (pressure of 400 Pa at 650 C), no dielectric maximum was observed. To explain this size dependence, we precisely investigated a particle structure by using synchrotron radiation. As a result, the particles were always composed of two layers, i.e., a surface cubic layer and a bulk tetragonal layer, and the thickness of the surface cubic layer decreased with increasing degree of vacuum during the preparation of BaTiO3 nanoparticles. Thus, we confirmed that the surface structure was an important factor in determining the dielectric properties of BaTiO3 nanoparticles.

AN EMPIRICAL STUDY OF JAPANESE AND AMERICAN CONSUMERS’ ATTRIBUTION OF RESPONSIBILITY ON THEIR DECISION-MAKING PROCESS: AN EYE-TRACKING APPROACH

Emi Moriuchi,Naoko Moriyoshi 글로벌지식마케팅경영학회 2020 Global Marketing Conference Vol.2020 No.11

2D Analysis of Droplet Size Distribution of Diesel Sprays by using Improved ILIDS Method

( Chang Seong Ryu ),( Yasuo Moriyoshi ),( Masato Yamada ),( Yuzo Aoyagi ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-

The characteristics of Diesel spray, such as droplet size, velocity and droplet size distribution were simultaneously measured by using an improved ILIDS (Interferometric Laser Imaging for Droplet Sizing) method. Experiments were performed with an accumulator type unit injector system and a constant-volume high-pressure vessel. The injection pressure and ambient gas pressure were changed from 50 MPa to 100 MPa and up to 1 MPa, respectively. Injection duration was set at 2 ms and measurements were made at 3.5 ms after the start of injection. A single hole nozzle with orifice diameter of 0.244 mm was used. The measurement region was chosen at 40-60 mm from the nozzle-tip. In this study, measurement region was set to 10× 10 mm. The obtained images were continuously accumulated in the memory of PC and processed using a commercial software in order to analyze the position of each droplet and the droplet size. Two dimensional cross-section tomograms of sprays were also taken with a double-pulsed 532 nm Nd-YAG laser sheet and 12 bit CCD camera. As a result, curve-fittings of Nukiyama-Tanasawa`s droplet size distribution function were carried out. Under the atmospheric pressure, Value of α became small with going downstream. Meanwhile, under the pressurized condition, the value and droplet distribution was almost same. Furthermore, SMD decreased with going downstream in case of ambient pressure of 0.1 MPa. However, under the pressurized condition, the tendency was reverse.