Mazda Motor Corporation

Toda Kogyo Corporation

Madza Motor Corporation

Seiji Miyoshi

Akihide Takami

Hiroshi Yamada

Hideharu Iwakuni

Kenji Okamoto

Masaaki Akamine

Koji Minoshima

Koichiro Harada

Masayuki Kuroki

Makoto Kyougoku

Junichi Taga

Masahiko Shigetsu

Kenichi Yamamoto

Youichi Kuji

Kenji Suzuki

Kazuya Yokota

Hisaya Kawabata

Tomoaki Urai

Yuki Murakami

Tomohiro Honda

Susumu Mineoi

Yuki Kooda

Ryota Fujimoto

Asako Sadai

Disclosed is an exhaust gas purifying catalyst, which comprises a catalyst layer formed on a honeycomb-shaped support. The catalyst layer is formed by mixing a catalyst powder (A) consisting of a composite oxide (RhZrCeNdO) which contains at least Ce, Zr, and a catalytic noble metal composition, and a catalyst powder (B) consisting of a Zr-based oxide (RhZrXO) which contains at least Zr and has Rh existing on a surface thereof. A ratio (RhZrXO/RhZrCeNdO) of a mass of the catalyst powder (B) to a total mass of the catalyst powder (A) and the catalyst powder (B) may be set in the range of 1 to 50%. Further, the catalyst powder (B) may consist of a composite oxide which contains Zr as a primary component, a rare-earth metal except Ce, and Rh. The exhaust gas purifying catalyst of the present invention can provide enhanced exhaust gas conversion efficiency.

Exhaust gas purifying catalyst and exhaust gas purifying method

An upstream catalyst and a downstream catalyst are disposed in an exhaust passage of an engine. The downstream catalyst contains in the same catalyst layer thereof. Rh-doped CeZrNd mixed oxide particles on which Rh is supported and active alumina particles on which Pt is supported. The upstream catalyst is a three-way catalyst containing an oxygen storage component having a lower oxygen storage capacity than the Rh-doped CeZrNd mixed oxide.

Exhaust gas catalytic conversion system

An exhaust gas purification catalyst comprises: an oxygen storage component constituted by a mixed oxide containing cerium and zirconium; and a catalytic metal carried on the oxygen storage component. The oxygen storage component is in the form of hollow secondary particles each formed so that primary particles of an average particle size of less than 10 nm cohere into a shell.

Exhaust gas purification catalyst

An exhaust gas purifying catalyst comprising: a honeycomb-like substrate disposed in an exhaust passage for an engine; and a catalytic layer formed on a cell wall of said substrate, said catalytic layer including a mixed oxide which contains Ce (cerium) and Zr (zirconium), and retains a catalytic noble metal in such a manner that said noble metal atoms are located at crystal lattice points or between the lattice points of the mixed oxide, wherein said mixed oxide includes a first mixed oxide containing CeOin a mass greater than that of ZrO, and a second mixed oxide containing ZrOin a mass greater than that of CeO.

Exhaust gas purifying catalyst

A Ce&#x2014;Zr mixed oxide is employed as an oxygen storage component for a lean-NOx catalyst, and catalytic precious metal atoms are placed at and/or between crystal lattice points of the mixed oxide. This structure prevents the sintering of the precious metal and accelerates movement of oxygen ions in each of crystallites of the Ce&#x2014;Zr mixed oxide to increase the oxygen storage/release amount of the mixed oxide, which enhances the NOx removal performance of the catalyst.

Catalytic converter comprises a carrier having exhaust gas passages therein, a lower catalytic layer coated over the carrier and comprising hollow oxide powder loaded with catalytic metal, and an upper catalytic layer coated over the lower catalytic layer, directly exposed to exhaust gas flowing in the exhaust gas passages and comprising solid oxide powder loaded with catalytic metal. The hollow oxide powder may be ceria or alumina base oxide. Further it may be mixed oxide such as Ce&#x2014;Zr mixed oxide or La contained alumina as well.

The present invention is intended to ensure the improvement in catalytic performance of an exhaust gas catalytic converter, which is an essential performance thereof, ensure the thermal resistance thereof and downsize the converter, i.e., improve the arrangeability thereof. The exhaust gas catalytic converter has an upstream catalyst and a downstream catalyst which are arranged in upstream and downstream sides of an engine exhaust passage through which exhaust gas flows. Each of the upstream catalyst and the downstream catalyst contains an oxygen storage component. The oxygen storage component in the upstream catalyst has a structure in which Rh atoms are placed at or between crystal lattice points of a mixed oxide containing Ce and Zr and has a larger amount of oxygen storage than the oxygen storage component in the downstream catalyst under the same temperature conditions.

Exhaust gas catalytic converter

The present invention relates to an exhaust gas purification catalytic material containing: (a) a mixed oxide containing Ce and Zr for storing and releasing oxygen; and (b) a precious metal catalyst made of one or more kinds of precious metals. The precious metal catalyst comprises a first precious metal catalyst component placed between atoms, at crystal lattice points and/or at oxygen defect sites of the mixed oxide and a second precious metal catalyst component loaded on the surface of the mixed oxide, thereby improving the thermal resistance, oxygen storage capacity and exhaust gas conversion performance of the catalytic material.

Exhaust gas purification catalytic material and method for fabricating the same

In an exhaust gas purification catalyst comprising a honeycomb support and a catalytic layer that is formed on wall surfaces of each cell of the honeycomb support and contains active alumina and a mixed oxide containing Ce, Zr and Nd and doped with catalytic precious metal, the mixed oxide has a CeO/ZrOmass ratio of 1.4 or more and the ratio of NdO/(CeO+ZrO+NdO) in the mixed oxide is 20 mass % or less.

Exhaust gas purification catalyst and oxygen storage component for the same

There are provided NOx trap catalyst to trap and release NOx based on air-fuel ratio, first fuel supply means for supplying gasoline, second fuel supply means for supplying hydrogen, engine operation detecting means for detecting engine operating condition, fuel ratio changing means for changing the ratio of gasoline and hydrogen, NOx release determining means for determining whether it is required for the NOx to be released based on a state of the trapped NOx, NOx releasing means for releasing the NOx trapped by making the air-fuel ratio rich when the NOx releasing requirement is determined, gasoline ratio increasing means for increasing the ratio of gasoline when NOx releasing requirement is determined and the air-fuel-ratio rich control is executed. Accordingly, improper vibrations or noises can be restrained from occurring when the rich air-fuel-ratio control is executed to release the trapped NOx from the NOx trap catalyst.

Control device of hydrogen engine

A catalyst comprises an HC trapping material that is capable of trapping HC in an exhaust gas under low temperatures and releasing HC with a raise in temperature and catalytic material containing a Ce&#x2014;Pr double oxide capable of oxidizing and purifying HC from the HC trapping material with a high efficiency.

An exhaust gas purifying device of the present invention comprises NOx trap catalyst including NOx trap material, catalytic metal and O2 storage material, NOx sensor, section for releasing NOx when NOx absorbed amount of the NOx trap catalyst reaches a specified amount, section for determining diagnosis conditions of the NOx trap catalyst, section for detecting termination of O2 release from the O2 storage material, and section for diagnosing O2 storage capacity according to output value (NO1) of the NOx sensor during a term from beginning of the oxygen concentration lowering by the NOx release section until termination of the O2 release and for diagnosing NOx reduction capacity of the catalytic metal according to output value (NO2) of the NOx sensor after termination of O2 release, wherein a speed of lowering oxygen concentration during the diagnosis is set so as to be slower than that during non-diagnosis.

Exhaust gas purifying device for engine

The present invention provides a catalyst for purifying an exhaust gas having excellent heat resistance and a small level of deterioration of the purifying ability of the exhaust gas even if the catalyst is exposed to a high temperature atmosphere for a long time. The catalyst for purifying an exhaust gas comprises a catalytic metal for oxidizing HC and CO and reducing NO for purification, and a mixed oxide containing Ce, Zr and Sr.

Catalyst for purifying exhaust gas and method for purifying exhaust gas with the catalyst

A catalyst for lowering NOx concentration in an exhaust gas is disposed in an exhaust gas passage of an engine. The catalyst composed of a catalyst layer formed on a substrate. A NOx absorber that absorbs NOx when an oxygen concentration in the exhaust gas is high and releases NOx when the oxygen concentration drops, and a precious metal for reducing NOx are supported on a support material as catalyst components, and the NOx absorber includes Ba, K, Sr, and Mg. By lowering the oxygen concentration in the exhaust gas and raising a temperature of the NOx absorber when sulfur component is absorbed excessively in the NOx absorber, it is possible to regenerate the catalyst from the S poisoning.

Device for purifying exhaust gas, method for purifying exhaust gas, catalyst for purifying exhaust gas, and method for manufacturing exhaust gas purifying catalyst

An engine control device, which is adapted for an engine provided with an NOx-absorbing material arranged in an exhaust passage for absorbing NOx in an oxygen-rich atmosphere, and releasing NOx and absorbing sulfur content when the oxygen concentration drops, includes a discriminator for judging whether the amount of sulfur absorbed by the NOx-absorbing material has reached a prescribed quantity, and a reductant concentration controller which increases the temperature of the NOx-absorbing material by decreasing a quantity related to EGR ratio for desulfurizing the NOx-absorbing material based on the result of judgment made by the discriminator. When the quantity related to the EGR ratio is decreased, the temperature of exhaust gas increases. Consequently, the temperature of the NOx-absorbing material increases and the sulfur in the NOx-absorbing material is freed and released.

Growing community of inventors

Hiroshima, Japan

Seiji Miyoshi