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.
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.
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 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.
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.