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AssigneeNGK Insulators, Ltd.
InventorsYoshiyuki Kasai, Yoshiro Ono, Ikuko Ishiyama
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An imaginary plane dividing a profile of a rough surface of a filter into halves with equal volume is defined as a mean plane. Assuming cutting the filter with the mean plane, a ratio of the total cross-sectional area of the recesses appearing to the whole area of the mean plane is defined as a Valley Level. An exhaust gas filter having a surface with a Valley Level of at most 20%, a porosity of 40% to 55% and an average pore diameter of 5 .mu.m to 50 .mu.m effectively collects fine particles contained in exhaust gases discharged from internal combustion engines, such as diesel engines, with little pressure loss, and has an improved releasability of deposited fine particles and can be readily regenerated by flow of blowback air, with high efficiency. When the filter has a specified two-layer structure, the Valley Level is readily controllable.
An exhaust gas filter for collecting fine particles contained in exhaust gases discharged from internal combustion engines, comprising a filter substrate and a filter layer provided on a surface of said filter substrate, said filter layer having a surface with a Valley Level of not more than 20%, and said filter substrate having a porosity of between 45% and 60% and an average pore diameter of between 10 .mu.m and 80 .mu.m.
An apparatus for treating exhaust gases discharged from internal combustion engines, comprising an exhaust gas filter for collecting fine particles contained in the exhaust gases, and an air-blowback means to regenerate said exhaust gas filter, said exhaust gas filter comprising a filter substrate and a filter layer provided on a surface of said filter substrate, said filter layer having a surface with a Valley Level of not more than 20%, and said filter substrate having a porosity of between 45% and 60% and an average pore diameter of between 10 .mu.m and 80 .mu.m.
Dependencies are inferred from the claim text.