Page 505 - Book Hosokawa Nanoparticle Technology Handbook

15 CERAMIC FILTER FOR TRAPPING DIESEL PARTICLES APPLICATIONS
[3] E. Brzozowski, M.S. Castro: J. Eur. Ceram. Soc., 20, [7] Y. Hakuta, H. Ura and H. Hayashi: Japanese Patent
2347–2355 (2000). No. 289737A (2005).
[4] R. Asiaie, W. Zhu, S.K. Akbar and P.K. Dutta: Chem. [8] T. Adschiri, K. Sue, Y. Hakuta and K. Arai:
Mater. 8, 226–234 (1996). J. Nanopart. Res., 3, 227–232 (2001).
[5] S.W. Lu, B.I. Lee, Z.L. Wang and W.D. Samuels: [9] Y. Hakuta, H. Ura, H. Hayashi and K. Arai: Mater.
J. Cryst. Growth, 219, 269–276 (2000). Lett., 59, 1387–1390 (2005).
[6] I.J. Clark, T. Takeuchi, N. Ohtori and D.C. Sinclair: [10] Y. Hakuta, H. Ura, H. Hayashi and K. Arai: Ind. Eng.
J. Mater. Chem., 9, 83–91 (1999). Chem. Res., 44, 840–846 (2005).

APPLICATION 15
15 CERAMIC FILTER FOR TRAPPING DIESEL PARTICLES

Exhaust gas discharged from diesel engine vehicles, 60
plant facilities, etc. has become a major concern as a JPN(H14)
cause of air pollution, health disturbances, and offen- Euro 3
sive odors. Gas emissions, especially those from 50
diesel engine vehicles, are drawing close attention for
their PM (Particulate Matter: suspended particulate 40
matter defined in Japan as particles with a grain
diameter of 10 m or less). The PM in gas emissions Euro 4
can be easily seen as black fumes. PM is now estab- PM (mg/km) 30
lished to be carcinogenic, and may act in ways simi-
lar to environmental hormones [1]. This redoubles 20 JPN New Long-term
the need to reduce the discharge of gas emissions and
nitrogen oxide. There are various ways to reduce the
10
harmful substances discharged from diesel engine US07 Tier2 Bin 5 Euro 5
vehicles. One is the common rail fuel injection sys-
tem. Through recent technical innovations, gas emis- 0
sions from diesel engine vehicles can now be 0 100 200 300 400 500 600
purified to some extent. Better purification has NOx (mg/km)
recently enabled the design of high-performance
diesel engine vehicles. Thanks to this improvement, Figure 15.1
in combination with the excellent fuel efficiency and Trends in exhaust gas regulation in each country.
durability of diesel engines, diesel engine vehicles
now make up about 50% of the total sales of passen-
ger cars in Europe. With the demand for diesel
engine vehicles increasing, further purification of given on several basic study items applied in the
gas emissions is extremely important. Automakers testing of the filter medium for practical use: the
will have to make diesel engine vehicles more trapping efficiency, pressure loss, strength, and heat
environment-friendly while maintaining their high resistance etc.
performance. Fig. 15.1 shows the regulatory trends
for the control of gas emissions from diesel engine 1. Production of PM
vehicles around the world. This control value for the
discharge of PM from diesel engines is equal to or The production of PM is thought to involve three
stricter than that from gasoline engines, and it con- processes: the PAH (Polycyclic Aromatic
tinues to grow stricter still. The elimination of air Hydrocarbon) production process, a process in
pollution by the DPF (Diesel Particulate Filter) is a which PAH grows into crystallites of soot, and a
very effective means to achieve the control value. process in which PAH aggregates into soot (see
The following sections describe the basic properties Fig. 15.2) [2]. Because diffusion combustion is the
and characteristics of a ceramic filter for trapping main process in diesel combustion, nothing can be
diesel particles with a porous silicon carbide done to eliminate the formation of local areas with
obtained by a recrystallization method. Details are excessive concentration. The unwanted outcome is

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