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Iizuka T.,Isuzu Advanced Engineering Center | Ouyang Q.,Shanghai JiaoTong University
Keikinzoku/Journal of Japan Institute of Light Metals | Year: 2013

SiC particle-reinforced AC4C based alloy (AC4C-Mg and AC4C-Cu) composites were fabricated by the melt stirring-gravity casting method in atmospheric, and the microstructures, strength and fatigue properties were studied. The tensile strength and the fatigue lives were substantially higher in the SiC particle-reinforced AC4C based alloy composites. Compared with the AC4C-based alloys, the fatigue lives of SiCp/AC4C-Mg and SiCp/AC4C-Cu composites at 250°C for 107 cycles increased by 29% and 27%, respectively. It was found that the effect of SiC particle on the fatigue life was more remarkable for the SiC particle-reinforced AC4C-based alloy composite tested at elevated temperature. SEM observations of the fractured specimens of the SiC particle-reinforced AC4C based alloy composites showed that almost no particles were found from the regions of the crack propagation of the fatigue surfaces. The formation of the plastic zone in the matrix due to the thermal expansion mismatch between the SiC particle and the matrix resisted the generation and the propagation of the fatigue crack, and contributed to the improvement of fatigue life. © 2013 The Japan Institute of Light Matals.

Iizuka T.,Isuzu Advanced Engineering Center | Ouyang Q.-B.,Shanghai JiaoTong University
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

MgAl2O4 particle-reinforced AC4C based alloy composites were fabricated by the stirring-casting method. The effects of the average sizes and the size distributions of MgAl2O4 particles on the dispersibility were investigated, and the microstructures, strength, and fatigue properties of MgAl2O4 particle-reinforced AC4C based alloy composites were evaluated. Tensile strength in the MgAl2O4 particle-reinforced AC4C based alloy composite was increased by using the classified particles. The fatigue limit at 107 cycles in the MgAl2O4 particle-reinforced AC4C-Cu composite increased by 27% compared to the unreinforced alloy at 250 °C. Dislocations were observed in the matrix around the MgAl 2O4 particle which resulted from the mismatch of thermal expansion coefficients between MgAl2O4 and Al, and resisted failure and caused fatigue cracks to propagate around the MgAl 2O4 particles, resulting in extensive crack deflection and crack bowing, which contributed to the improvement of fatigue strength. © 2014 The Nonferrous Metals Society of China.

Ishikawa R.,Shibaura Institute of Technology | Sato K.,Shibaura Institute of Technology | Shimomura S.,Shibaura Institute of Technology | Nishimura R.,Isuzu Advanced Engineering Center
2013 International Conference on Electrical Machines and Systems, ICEMS 2013 | Year: 2013

Permanent magnet vernier machines, PMVM, have magnetic gear effect, which yields a large torque and increases torque per current. We, the authors, have focused on an outer rotor type in-wheel machine for EV so as to take the advantage of PMVM and previously proposed a machine with NdFeB bond magnets which satisfied required characteristics in, both torque and output power, whose characteristics were verified by a computer simulation. However, the current density in armature winding conductor was very high. It wasn't suitable for in-wheel system without cooling system. This paper, therefore, proposes an improvement of the disadvantage in the previously proposed machine. Consequently, the current density has decreased to half compared with the unimproved machine. That magnitude was small enough to apply the machine to in-wheel system. © 2013 IEEE.

Nguyen T.Q.,Osaka University | Escano M.C.S.,Osaka University | Nakanishi H.,Osaka University | Kasai H.,Osaka University | And 3 more authors.
Applied Surface Science | Year: 2014

We investigated the reactivity of CeO2-supported Pt4 cluster (denoted as Pt4/CeO2(1 1 1)) toward O2 adsorption and dissociation as well as the geometry/electronic properties associated with such metal oxide supported cluster system using density functional theory and on-site Coulomb interaction correction via the Hubbard-like term, U (DFT+U). It was found that Pt4 binds strongly to CeO2(1 1 1) via PtOCe bonds which act as "anchors" between the surface and the cluster, confirming its non-sintering as found in experiments. The adsorption of the cluster involves net electron transfer to CeO2, however, charge redistribution also happens within the cluster (from Pt atom bonded to the surface to the Pt on top of the cluster). This charge couples to the top Pt leading to reduce its spin moment as compared to that of unsupported cluster. When O2 adsorbs on Pt 4/CeO2(1 1 1), while it prefers Pt vertex site near the CeO2 surface, the OO bond elongation is more profound at the PtPt edges. The energy barrier for dissociating O2 from this edge site precursor state is smallest. A correlation between the OO bond length at the precursor state and the stability at the transition state is revealed. Finally, the barrier for dissociation in unsupported Pt4 is lower, indicating suppression of the cluster's reactivity due to the support. We attribute this to the hybridization of Pt-5d orbitals with O-2p orbitals in CeO2(1 1 1) leading to the broadening of Pt-5d states near the Fermi level. © 2013 Elsevier B.V. All rights reserved.

Nitta J.,Isuzu Advanced Engineering Center | Minato A.,Isuzu Advanced Engineering Center | Shimazaki N.,Isuzu Advanced Engineering Center
SAE Technical Papers | Year: 2011

An exhaust turbocharging system makes it possible to increase the brake mean effective pressure (BMEP) and lower emissions levels for a diesel engine while further improving the thermal efficiency. However, in order to meet future emission regulations, further reductions in NOx and particle matter (PM) emissions are necessary. In addition, the diesel engine should have further reductions in fuel consumption to reduce CO2, which is one of the main greenhouse gases. Authors participated in a program for the comprehensive technological development of innovative, next-generation, low-pollution vehicles with the New Energy and Industrial Technology Development Organization (NEDO) [1] from 2004 through 2008 in cooperation with the National Institute of Advanced Industrial Science and Technology (AIST). A low-emission and high-efficiency diesel engine system was developed to meet the target of NEDO project. The turbocharging system which makes possible the high boost and high exhaust gas recirculation (EGR) rate was evaluated by using simulation. Thus, the sequential three-stage turbocharging system was proposed and the engine that was equipped this turbocharging system was tested. Finally, the project target was achieved by the three-stage turbocharging system with the combined use of the exhaust aftertreatment system. This paper describes the simulation evaluation of the turbocharging systems, which was developed as an elemental technology in the NEDO project, and test results on the improvement in the tradeoff between NOx emission and fuel consumption. Copyright © 2011 SAE International.

Kitabatake R.,Isuzu Advanced Engineering Center | Minato A.,Isuzu Advanced Engineering Center | Inukai N.,Isuzu Advanced Engineering Center | Shimazaki N.,Isuzu Advanced Engineering Center
SAE International Journal of Engines | Year: 2011

Further improvement in fuel consumption is needed for diesel engines to address regulatory requirement particularly for heavy duty diesel in Japan enforced in 2015, in addition to the compliance to the regulatory requirements for exhaust emission, which seems to be more stringent in future. The authors have participated in the project of "Comprehensive Technological Development of Innovative, Next-Generation, Low-Pollution Vehicles" organized by New Energy and Industrial Technology Development Organization (NEDO), and innovative devices such as multi stage boosting system, ultra high-pressure fuel injection system and variable valve actuation (camless) system had been developed in this project from a standpoint of simultaneous improvement of fuel consumption and exhaust emission. In camless system, intake and exhaust valves are driven by hydraulic pressure. So, fully flexible setting of opening and closure timings and lift of the intake and exhaust valves is possible. In this paper, steady-state operation test was conducted by adopting a combustion chamber with geometric compression ratio of 20.0 and an Electro-Hydraulic Camless System in the multi-cylinder engine with 3 stage turbo charge system. The engine performance and exhaust emissions were compared to same base engine equipped with 3 stage turbo system, piston of geometric compression ratio of 16.2 and cam drive valve train. As a result of steady-state operation test, potential of improvement of fuel economy was indicated in this engine system. In addition, due to cylinder deactivation operation, further improvement of fuel economy was achieved in extremely low load range by reduction of heat loss. With regard to the BSFC based on JE05 mode -converted value with giving consideration to the result of cylinder deactivation operation, improvement of 8.9% was obtained. With regard to the early exhaust valve opening (EEVO) for which effect to improve turbo charger response is expected as well as the negative valve overlap (NVO) for which making up for delay of external Exhaust Gas Recirculation (EGR) by internal EGR, the operation for 70 seconds was extracted from JE05 mode operation to implement partially transient operation on trial basis. It was confirmed that both EEVO and NVO were feasible by using this camless system. Further simultaneous reduction of both fuel consumption and exhaust emission in JE05 mode operation is expected by controlling intake and exhaust valve lift with giving consideration to the effect of external disturbance, improved thermal efficiency by increase of expansion ratio, implementation of each cylinder control for each load range including the switching control to cylinder deactivation operation, and suppression of spike-like NOx and soot emissions by adopting EEVO and NVO. © 2011 SAE International.

Minato A.,Isuzu Advanced Engineering Center | Shimazaki N.,Isuzu Advanced Engineering Center
SAE International Journal of Engines | Year: 2011

Complexity of the modern diesel engine has increased to meet the stringent future emission regulations especially for NOx (nitrogen oxide) and PM (particulate matter). Air management system including exhaust gas recirculation (EGR), turbocharger and variable valve actuation (VVA) must be optimized of its design and control algorithm for combustion improvement coupled with precision control of fuel injection. As a matter of course, the optimization of aftertreatment system is extremely important for the exhaust emissions reduction. In addition, improvement of fuel consumption is very important from the standpoint of response to energy security and reduction of CO2 (carbon dioxide) emission as the greenhouse gas. However an enormous amount of energy will be required to develop such kind of the complex engine system by conventional actual testing. Therefore, the total engine simulation system (TESS) with quasi real time processing and relatively high precision model for prediction of fuel consumption and exhaust emissions was developed in this study. The TESS consists of the zero-dimensional gas flow model and the aftertreatment model written by Simulink code. In addition, the zero-dimensional multi-zone diesel combustion model, HIDECS (Hiroshima University diesel engine combustion simulation) which was developed by Hiroyasu et al. is embedded in the TESS. Since modeling logic of the HIDECS is based on the phenomenalism, prediction accuracy and calculation speed are well balanced. The premixed compression ignition (PCI) combustion will be a key technology for simultaneous reduction of exhaust emissions and fuel consumption. However, there are some problems to predict the PCI combustion on the original HIDECS. Therefore, modification of the HIDECS model to predict the PCI combustion was also conducted in this study. Modified model uses pseudo method for consideration of mixing process that is strongly governed by oxygen concentration. Additionally, equation about ignition delay was also modified to fit the EGR rate changing. In this result, the modified HIDECS can predict exhaust emissions and fuel consumption on the PCI combustion. Finally, performance estimation of the most advanced diesel engine with multi-stage boosting, massive EGR and ultra high pressure injection was conducted by using the TESS including the modified HIDECS model. Experiment of single cylinder engine which has the VVA system was also conducted to make the TESS effectiveness clear and to get knowledge for further improvement of fuel consumption. In this result, effectiveness of the TESS for system investigation of the future diesel engine is clear. In addition, technological direction of fuel consumption improvement is indicated by the TESS and experimental result. This project was conducted as a part of the comprehensive technological development of innovative, next-generation, low-pollution vehicles program in the New Energy and Industrial Technology Development Organization (NEDO) of Japan. © 2011 SAE International.

Suzuki Y.,National Institute of AIST | Tsujimura T.,National Institute of AIST | Mita T.,Isuzu Advanced Engineering Center
SAE International Journal of Engines | Year: 2015

Hydrogen can be produced by electrolyzation with renewable electricity and the combustion products of hydrogen mixture include no CO, CO2 and hydrocarbons. In this study, engine performance with hydrogen / diesel dual fuel (hydrogen DDF) operation in a multi-cylinder diesel engine is investigated due to clarify advantages and disadvantages of hydrogen DDF operation. Hydrogen DDF operation under several brake power conditions are evaluated by changing a rate of hydrogen to total input energy (H2 rate). As H2 rate is increased, an amount of diesel fuel is decreased to keep a given torque constant. When the hydrogen DDF engine is operated with EGR, Exhaust gas components including carbon are improved or suppressed to same level as conventional diesel combustion. In addition, brake thermal efficiency is improved to 40% by increase in H2 rate that advances combustion phasing under higher power condition. On the other hand, NOx emission is much higher than one of conventional diesel engine. Additionally, hydrogen DDF engine operation at higher engine load with high H2 rate is limited by a variability of in-cylinder pressure among each cylinder. Mixing hydrogen and intake air will be encouraged to introduce homogeneous mixture to each cylinder. Following the result of increase in NOx emission under hydrogen DDF operation, we evaluate the effects of EGR (Exhaust Gas Recirculation) on the performance. Under 40kW power and H2 rate 55% condition. When EGR rate is around 20 %, the emission level of hydrogen DDF engine is at the same level as a mass-production diesel engine for heavy duty vehicles. However, there're still problems on soot emission and cylinder-to-cylinder pressure variation. Copyright © 2015 SAE International.

Ishikawa N.,Isuzu Advanced Engineering Center
International Journal of Engine Research | Year: 2012

The engine performance and emissions from a 3 l diesel engine equipped with a mechanical supercharger are investigated experimentally, and the advantages and disadvantages of the mechanical supercharger system are discussed in a comparison with performances and emissions from a corresponding 3 l diesel engine equipped with a turbocharger. An experiment conducted under steady-state conditions shows that the mechanical supercharger delivers higher boost pressures than the turbocharger under steady-state low- and middle-load operating conditions, and that the higher boost pressure allows the application of higher amounts of exhaust gas recirculation (EGR), which leads to lower NOx emissions. In a transient test, the fuel flowrate is increased instantly from a low to high rate at a constant engine speed, and T 90, which is the time required for the mechanical supercharger to achieve 90 per cent of the steady-state boost pressure, is found to be considerably shortened as compared to T90 obtained in a similar test with a corresponding turbocharged engine. In addition, the Japanese JE05 test result shows that NOx emission from the 3 l engine equipped with the mechanical supercharger is lower by 50 per cent than the engine with the turbocharger at a common level of soot emissions. However, the fuel consumption rate is worsened by 5.5 per cent due to the drive loses of the supercharger. Further study for reducing the fuel penalty is necessary to apply the mechanical supercharger to practical diesel engine systems. © 2012 IMechE.

Arato K.,Isuzu Advanced Engineering Center | Takashima T.,Isuzu Advanced Engineering Center
SAE International Journal of Engines | Year: 2015

A method to improve fuel consumption in diesel engines is to enhance their theoretical thermal efficiency by increasing their compression ratio. However, this results in an increase in heat loss due to the elevation of the concomitant in-cylinder temperature and the expansion of the impingement area between fuel spray and chamber wall. Therefore, reducing heat loss to the chamber wall is important to effectively benefit from a high compression ratio. To meet this challenge, in this study, we optimized the combustion chamber shape using the three-dimensional computational fluid dynamics (CFD) simulation software, CONVERGE. A rationale proposed by the University of Wisconsin-Madison was selected to outline the shape and combined with a multiobjective optimization software, modeFRONTIER. The calculations produced a shallow dishlike combustion chamber comprising a plateau at its center that may reduce heat loss. In this system, a portion of fuel spray remained at the center of the combustion chamber because of wall impingement. The lower half of this spray developed along the chamber wall, partially blocking air entrainment. These phenomena resulted in weak premixed combustion, lowering the combustion temperature and thus reducing heat loss. Furthermore, experiments using a single-cylinder engine were performed to evaluate the effect of the optimized combustion chamber shape on heat loss. The optimized combustion chamber improved fuel consumption under high load and advanced injection timing conditions. A weak premixed combustion was observed, as predicted by the CFD calculation. The thermal balance analysis also revealed that heat loss from the cylinder decreased while exhaust loss increased. Copyright © 2015 SAE International.

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