Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Emitec Gesellschaft Fuer Emissionstechnologie Mbh

Cataler Corporation

Seiji Okawara

Koichi Kojima

Mikio Ishihara

Makoto Tsuji

Mamoru Nishimura

Mikio Murachi

Kiyoshi Yamazaki

Yuji Sakakibara

Takuya Kondo

Daisuke Oki

Susumu Sarai

An exhaust gas purifying apparatus is comprised of a plurality of exhaust gas passages, and a filter bodyinstalled in the exhaust gas passages. The exhaust gas passage contains a filter-conducting portionof conducting the exhaust gas to the filter body, and a filter-bypassing portionof bypassing the filter-conducting portionby branching out to an exhaust gas passage adjacent from the filter-conducting portion. When PMs are deposited on the filter-conducting portionand an exhaust gas pressure loss is increased, the exhaust gas is branched out from the filter-bypassing portionto flow.

Exhaust gas purifying apparatus

To provide a filter catalyst in which the closure of ventilation holes by a catalytic layer is inhibited. A filter catalyst of the present invention is characterized in that it has pores of 1-20 &#x3bc;m in a porosity of 11% or more. The filter catalyst of the present invention has an effect of being capable of inhibiting the rise of pressure loss when sufficient particulates deposit.

Filter catalyst

An exhaust gas-purifying apparatus includes an NOsorbing-and-reducing first catalyst, a filter second catalyst, and an NOsorbing-and-reducing third catalyst, which are disposed in an exhaust system in this order from a downstream side to an upstream side of a flow of exhaust gases. In the exhaust system, a liquid reducing agent is supplied into the exhaust gases intermittently. The first catalyst exhibits a remarkably high NOpurifying ability, because not only the third catalyst and the second catalyst gasify, crack and homogenize the reducing gas fully but also the reactions at the third and second catalysts elevate the temperature of exhaust gases. Thus, the exhaust gas-purifying apparatus can purify PMs and NOefficiently.

Exhaust gas-purifying apparatus

A filter catalyst for purifying exhaust gases having a catalytic layer comprising the first catalyst supporthaving an average particle diameter of 1 &#x3bc;m or less, the second catalyst supporthaving an average particle diameter from 1/20 to &#xbd; of the average pore diameter of the filter cellular wallsand catalytic ingredients, on the filter cellular wallshaving an average pore diameter of from 20 to 40 &#x3bc;m, and the catalytic layer having uneven surfaces is used. Since the second catalyst support hardly enters into the pore with a diameter of 20 &#x3bc;m or less, it exists partly on the filter cellular walls and the inside surface of the wall. Therefore, since particles collide with the convex part of the catalytic layer, it becomes possible to collect them easily and the collecting rate for particles and the ability of the particles purification are improved.

Filter catalyst for purifying exhaust gases and its manufacturing method thereof

A filter catalyst is for purifying exhaust gases emitted from internal combustion engines and including particulates, and includes a wall-flow honeycomb structure and an upstream-side straight honeycomb structure. The wall-flow honeycomb structure includes inlet cells clogged on the downstream side of the exhaust gases, outlet cells neighboring the inlet cells and clogged on the upstream side of the exhaust gases, filter cellular walls demarcating the inlet cells and the outlet cells and having pores, and a catalytic layer formed on the surface of the filter cellular walls and/or the surface of the pores of the filter cellular walls. The upstream-side straight honeycomb structure is disposed on the upstream side of the exhaust gases with respect to the wall-flow honeycomb structure, is provided integrally with the wall-flow honeycomb structure, and includes upstream-side straight cells in which the exhaust gases flow straight, and upstream-side cellular walls demarcating the upstream-side straight cells.

Filter catalyst for purifying exhaust gases

According to the method of the present invention, NO (nitrogen monoxide) in the exhaust gas of a diesel engine is first oxidized to NO.sub.2 (nitrogen dioxide) by an oxidizing catalyst. Further, carbon particles in the exhaust gas are trapped by a DPF (diesel particulate filter). The exhaust gas containing NO.sub.2 formed by oxidation of nitrogen monoxide is, then, fed to the DPF, and NO.sub.2 in the exhaust gas reacts with the carbon particles trapped in the DPF. When the NO.sub.2 reacts with carbon particles, carbon particles are oxidized (burned) by NO.sub.2 and removed from DPF, and, at the same time, NO.sub.2 is reduced to NO by the carbon particles. The exhaust gas containing NO formed by the reaction between the carbon particles and NO.sub.2 is fed to an NO.sub.X absorbent. In the NO.sub.X absorbent, NO is absorbed by the NO.sub.X absorbent and, thereby, removed from the exhaust gas. Therefore, according this method, the carbon particles collected by the DPF can be easily burned by NO.sub.2, thereby being removed from the DPF without increasing the amount of NO released to the atmosphere.

Growing community of inventors

Toyota, Japan

Seiji Okawara