Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

In recent years, emission regulations have become more stringent, and particulate matter (PM) emitted from gasoline engine vehicles is also subject to regulation. PM emitted from a gasoline engine is suppressed by a gasoline particulate filter (GPF). However, unlike diesel engines, exhaust from gasoline engines flows into the GPF under more stringent conditions. Therefore, in this study, we performed numerical calculations based on WLTC, taking into account fluctuations in exhaust gas from gasoline engines, and confirmed the behavior of PM deposition and regeneration.　At that time, the numerical calculation model of the previous research was also improved.　Furthermore, a catalyst was supported on the GPF, and the catalyst performance was evaluated.　As a result, it was suggested that continuous regeneration would be possible by improving the performance of the catalyst.

DOI： https://doi.org/10.11351/jsaeronbun.53.360

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

The particulate matter (PM) emitted from the diesel engine is collected and removed by the diesel particulate filter (DPF). When performing PM removal, it is necessary to raise the temperature of exhaust gas, so deterioration of fuel efficiency is a serious problem. Therefore, we aim to propose an optimal DPF structure with catalyst addition. In this study, PM combustion behavior inside the DPF when the catalyst is supported is carried out by numerical calculation. As a result, the effectiveness of the catalyst is recognized. It is found that there is a difference in the amount of PM combustion change according to the difference in the activation energy. In this result, it can be suggested that a catalyst having activation energy ΔE = 120 KJ/mol or less is effective. It is also possible to completely remove PM in a single regeneration by using a catalyst with low activation energy or by increasing the exhaust gas temperature. The calculation technique we proposed will enable the qualitative examination of the structure of DPF with catalyst addition, which can be useful for the optimization design of DPF.

DOI： 10.11351/jsaeronbun.52.257

CiNii Research

Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11214-020-00775-7

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Metal-dispersed Pd/ZrO2 composites were derived from amorphous Zr65Pd35 alloy and their catalytic behavior for diesel soot combustion was studied. X-ray diffractograms and scanning electron micrographs indicated that mixtures of ZrO2 phase and the dispersed metallic phase were formed in the resulting material after heat treatment at 800 degrees C in air. The oxidized alloy resulted in the enhanced soot combustion activity. The removal property of catalyst, evaluated as temperature, is almost 100 degrees C better than that in the non-catalyzed reaction. The combustion processes were observed by in situ high temperature optical microscopy (HTOM) and ex situ electron microscopy with different scales. The secondary soot particle started the combustion at the primary soot near catalyst. Upon heating to higher temperature between 570 degrees C and 590 degrees C the soot layer rapidly disappeared in in situ HTOM, while both the black band and dispersed part of soot on a alumina substrate remained without combustion even kept at 650 degrees C. Therefore, soot did not move with micron-order distance and its combustion process should depend on their contact points of catalyst surfaces and soot aggregate. This work provided a new type of catalytic material prepared from amorphous alloys which was effective soot combustion catalysis. (c) 2019 The Japan Society of Applied Physics

DOI： 10.7567/1347-4065/ab45fb

Web of Science

Scopus

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

The particulate matter (PM) emitted from the diesel engine is collected and removed by the diesel particulate filter (DPF). When performing PM removal, it is necessary to raise the temperature of exhaust gas, so deterioration of fuel efficiency is a serious problem. Therefore, we aim to propose an optimal DPF structure. In this study, we confirmed the dependence of the shape of the DPF during PM deposition-regeneration process using a numerical calculation. The quick change of the pressure drop and the amount of combustion of PM is smaller when the length of the DPF becomes larger. When the DPF length is long, the residual of PM amount at the outlet of DPF decreases. And the PM on the whole surface burns. When the after 10－15 deposition combustion repetitions, the amount of change of PM shows the same pattern. This model can be used for the optimal design of catalytic DPFs by assuming some modes of operation of the DPF device before the experimental approach.

DOI： 10.11351/jsaeronbun.51.882

CiNii Research

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In this study, we proposed a numerical method to estimate the behavior of PM distribution in DPF both in PM-deposition and regeneration process. In the result, we found that PM oxidation was occasionally incomplete and partially remained in the DPF even if the PM deposition-regeneration process was repeated in the DPF. In such case, the phenomenon that the oxygen supply slightly decreased towards the rear part of the DPF was found, so that the remained PM in the DPF induced the new PM deposition. By using a novel model, PM deposition distribution and modeling of the oxidization reaction, where deposition-regeneration is especially repeated within DPF, could be performed and time-dependent behavior of pressure loss was considered. The present modeling will make possible suggest the required timing which performs compulsive reproduction control of DPF.

DOI： 10.11351/jsaeronbun.51.238

CiNii Research

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

The particulate matter (PM) discharged from the diesel engine is collected by a diesel particulate filter (DPF) and then removed. Deterioration of fuel consumption is a serious problem since exhaust gas temperature must be increased when PM removal is performed. In this study, the numerical computation for both the behavior of PM distribution in the DPF during PM deposition-regeneration process and the heat distribution in the DPF was performed. The temperature-distribution and its change in DPF as a function of the time during PM combustion were calculated by a newly developed model. It was concluded that the amount of increasing temperature change was far larger backside in direction than that near the entrance of an inflow way. The present model can be used for optimal designing of DPF with a catalyst by assuming several operation modes of DPF device before an experimental approach.

DOI： 10.11351/jsaeronbun.51.274

Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Materials Science, Japan  

<p>The diesel particulate filter (DPF) has attracted strong attention as a desirable after-treatment device for the particulate matter(PM) contained in exhaust gas of diesel engine. When particulate matter was deposited on a DPF, the pressure drop increases due to the PM trapping in the surface cavities of the DPF. In this study, we compared the dependence of the shape and depth of the pore of the DPF on the PM trapping process by total model and numerical calculation. We found that the pressure drop and elapsed time of the PM trapping varied, significantly depending on the pore shape of the DPF surface. Further we examined the relative importance of the amount of PM deposit and the surface cavity shape of the DPF, and found that the pressure drop was lower when the shape of surface cavity in DPF became flatter and shallower. The result provides a quantitative evaluation and design of the surface cavity in the DPF leading to better production process of porous ceramic parts. </p>

DOI： 10.2472/jsms.67.562

Scopus

CiNii Books

Publishing type：Research paper (scientific journal)   Publisher：Advances in Space Research  

DOI： 10.1016/j.asr.2015.04.009

Scopus

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

The process of soot trapping in a hexagonal cell geometry diesel particulate filters (HEX DPF) in surface pores filtration made of aluminum titanium oxide were investigated through a simple analysis based on Darcy's law through the wall and deposited soot layer. In this study, we focused on the trapping process of the HEX DPF cell in surface pores filtration by Numerical Simulation. The HEX DPF had two types of flow: one was a flow through a wall between inlet and outlet channels (inlet/outlet wall flow), and the other was a flow which was introduced into a wall between inlet and inlet channels, and was turned toward the direction parallel to the wall, and finally exited into the outlet channel (bypass flow). As a result, the process of soot trapping in surface pores filtration was shown by numerical simulation. It was possible to express the transition process from surface pores filtration to cake filtration.

DOI： 10.11351/jsaeronbun.46.313

CiNii Books

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

The phenomena of soot trapping and oxidation in a hexagonal cell geometry DPF made of aluminum titanium oxide were investigated through microscopic visualization experiment and a simple analysis based on Darcy's law through the wall and the deposited soot layer. There were two types of flow: one was a flow through a wall between inlet and outlet channels (inlet/outlet wall flow), and the other was a flow which was introduced into a wall between inlet and inlet channels, and was turned toward the direction parallel to the wall, and finally exited into the outlet channel (bypass flow). The flow rate of the bypass flow was increased with a thickness of soot layer deposited on the inlet/outlet wall. As a result, the soot was trapped even on the inlet/inlet wall surface. In the regeneration process, depending on the flow rate of the bypass flow, the maximum temperature for the hexagonal cell DPF became lower compared with that for the conventional DPF.

DOI： https://doi.org/10.20485/jsaeijae.6.1_31

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

A piezoelectric lead-zirconate-titanate (PZT) element was exposed to a 400MeV/n xenon beam and the radiation effect on the element was studied as a variation of resonant and antiresonant frequencies by the resonance method. A possible effect of heating the element on the resonant frequency was avoided by using data obtained while the temperature of the element was kept constant. Consequently, the variation of the resonant frequency was empirically represented by a simple function of the amount of accumulated energy in the element. We therefore discuss the piezoelectric PZT element as a potential detector for high-level radiation. We point out that a piezoelectric equation including the heat term is required to explain the experimental results. (C) 2014 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.53.066602

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

A radiation detector fabricated using piezoelectric lead zirconate titanate (PZT) has been studied by irradiating it with a 400 MeV/n xenon (Xe) beam. The beam diameter was controlled to change the irradiation conditions. It was found that the magnitude of the output observed from the PZT detector may be related to the number of Xe ions per unit area per unit time within the limits of the experimental conditions. (C) 2013 Elsevier B.V. All rights reserved

DOI： 10.1016/j.nima.2013.11.029

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

The variation of the electromechanical coupling factor (ECF) was measured by bombarding a piezoelectric lead zirconate titanate (PZT) element with 400 MeV/n xenon ions. The element was exposed to energies up to 10(4) J, during which time the ECF was observed by the resonance method. The ECF gradually decreased with the energy accumulated during irradiation, and its behavior was scaled with an empirical formula. This decrease suggests that the piezoelectric quality deteriorated; hence, the sensitivity of the PZT radiation detector was considered to be degraded as well. The variation ultimately originated in resonance-associated processes. A potential detector suitable for use in severe-radiation environments was discussed. (C) 2013 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.52.126604

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://ui.adsabs.harvard.edu/link_gateway/2013EP&S...65..167K/doi:10.5047/eps.2012.08.011

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

The influence of a thermal reflector on the sensitivity of a lead-zirconate-titanate element is studied by bombarding the element with hypervelocity microparticles. The reflector is a 60-mu m-thick layer made of polyimide resin that coats the surface of the element. By applying the fast Fourier transform method to data analysis, impact information is obtained through the fundamental resonant component. As a result, the sensitivity of the element is considerably reduced by the reflector. In addition, it is found that the sensitivity is substantially position-independent. (C) 2013 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.52.028002

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN SOC APPLIED PHYSICS  

A possible position dependence of the signal amplitudes generated by a piezoelectric lead-zirconate-titanate (PZT) detector was studied by bombarding the PZT element with hypervelocity microparticles. The detector was equipped with a set of asymmetrically arranged electrodes. The characteristic features of the element were analyzed using the amplitudes of the fundamental resonant component caused by collisions. As a result, the sensitivity of the element measured with direct collisions onto the collector was found to be one order of magnitude greater than that in the external area of the collector. (C) 2012 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.51.098004

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1029/2012JE004064

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.5047/eps.2011.05.038

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.2322/tastj.8.Pk_7

Event date： 2020.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：online  

Event date： 2020.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Digital summit  

Event date： 2019.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto  

Language：Japanese   Presentation type：Oral presentation (general)