摘要:
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.
摘要:
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.
摘要:
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 NOx for purification, and a mixed oxide containing Ce, Zr and Sr.
摘要:
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—Pr double oxide capable of oxidizing and purifying HC from the HC trapping material with a high efficiency.
摘要:
Disclosed is an exhaust gas purifying catalyst, which comprises an oxygen absorbing material having a catalytic noble metal arranged at a lattice position or an interlattice position of a crystal structure of a composite oxide containing Ce and Zr, which is capable of sufficiently exhibiting a catalytic function even if a ZrO2 mass ratio is out of the range of 20 to 30 mass % or 65 to 90 mass %. Specifically, in an exhaust gas purifying catalyst formed with a catalyst layer including a cerium-zirconium (CeZr) composite oxide, the composite oxide contains ceria (CeO2) and zirconia (ZrO2) in such a manner that a mass ratio of ceria to a total mass of ceria and zirconia falls within the range of 36 to 64 mass %. Further, the composite oxide contains, in the form of an oxide, a rare-earth metal other than cerium (Ce), in the range of 3 to 20 mass % with respect to a total mass of the composite oxide.
摘要:
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.
摘要:
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—Zr mixed oxide or La contained alumina as well.
摘要:
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 CeO2/ZrO2 mass ratio of 1.4 or more and the ratio of Nd2O3/(CeO2+ZrO2+Nd2O3) in the mixed oxide is 20 mass % or less.
摘要翻译:在包含蜂窝状载体和催化剂层的废气净化催化剂中,所述催化剂层形成在蜂窝状载体的各电池单元的壁面上,并且含有活性氧化铝和含有Ce,Zr和Nd的混合氧化物并掺杂有催化剂的贵金属, 氧化物具有1.4或更大的CeO 2 / ZrO 2质量比,并且Nd 2 O 3 O 3的比例 混合氧化物中的/(CeO 2 + ZrO 2 + Nd 2 O 3 3)为20质量%或 减。
摘要:
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—Zr mixed oxide or La contained alumina as well.
摘要:
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.