Nissan Motor Company Limited

Hitoshi Onodera

Hiroshi Akama

Masahiro Takaya

Hiroaki Kaneko

Shinji Yamamoto

Yasunari Hanaki

Toru Nishizawa

Katsuo Suga

Yoshiaki Hiramoto

Hiroyuki Kanesaka

Hideaki Morisaka

Hiroshi Morita

Takashi Shirakawa

Manabu Miura

Yasuhisa Kitahara

Masayuki Fukuhara

An exhaust gas purifying system includes: a NOx trapping agent () which adsorbs nitrogen oxide when an excess air ratio of exhaust gas is more than 1, and releases nitrogen oxide when the excess air ratio is 1 or less; a NOx purifying catalyst () which reduces nitrogen oxide to nitrogen; and an oxygen concentration controller which controls oxygen concentration in the exhaust gas. When the excess air ratio of the exhaust gas is more than 1, nitrogen oxide is adsorbed to the NOx trapping agent (). When the excess air ratio of the exhaust gas is 1 or less, the oxygen concentration controller controls the oxygen concentration of the exhaust gas at an inlet of the NOx purifying catalyst between 0.8 and 1.5% by volume, so that the NOx purifying catalyst reduces nitrogen oxide released from the NOx trapping agent.

Exhaust gas purifying system

A particulate matter purifying material is used for a filter catalyst for purifying particulate matter that is disposed in an exhaust gas flow path of an internal combustion engine, traps the particulate matter in exhaust gas generated in the internal combustion engine, and burns the particulate matter to be deposited, so as to be regenerated. The particulate matter purifying material includes an oxide containing cerium (Ce) having an oxygen storage-release capacity, and at least one metal (Me) selected from the group consisting of Zr, Y, La, Pr, Sr, Nb and Nd, wherein a content ratio (Ce:Me) of cerium to the metal is 6:4 to 9:1 in terms of an atomic ratio, and a degree of crystallinity (CR) represented by the following formula (1) is within a range of 25 to 60%:Degree of crystallinity ()=&#xd7;100(%)&#x2003;&#x2003;(1)wherein I represents an X-ray diffraction peak intensity with regard to a (111) plane of a CeOphase in the particulate matter purifying material, and Irepresents the X-ray diffraction peak intensity with regard to the (111) plane of the CeOphase after the particulate matter purifying material is baked in air at 1000&#xb0; C.

Particulate matter purifying material, filter catalyst for purifying particulate matter using particulate matter purifying material, and method of regenerating filter catalyst for purifying particulate matter

An exhaust gas purifying system () includes: a NOx purifying catalyst () that is disposed in an exhaust gas flow path () to purify nitrogen oxide; and an HC generator () that is disposed upstream of the NOx purifying catalyst () in the exhaust gas flow path () to generate at least one of acetylene, a hydrocarbon with a carbon number of 2 to 5 other than acetylene, and an aromatic hydrocarbon from a hydrocarbon contained in an exhaust gas. In addition, an exhaust gas purifying method using the exhaust gas purifying system includes the step of adjusting an oxygen concentration in the exhaust gas supplied to the HC generation catalyst (A,A) to 0.8 to 1.5 vol % when an air-fuel ratio is stoichiometric or rich.

Exhaust gas purifying system and exhaust gas purifying method using the same

An exhaust gas purifying catalyst () includes: a three-dimensional structural substrate () having a plurality of cells () partitioned by cell walls () having pores (); and catalyst layers () formed in the three-dimensional structural substrate (). The catalyst layers () have pore-cover portions () formed on surfaces () of the pores () of the cell walls (). In addition, the catalyst layers () of the pore-cover portions () have activated pores () with a pore diameter of 0.1 micrometers to 10 micrometers. In the exhaust gas purifying catalyst (), the obstruction of the vent holes (pores ()) in the catalyst layers () can be controlled, and the pressure loss can be reduced.

Exhaust gas purifying catalyst and manufacturing method of the same

The present invention relates to a method for regenerating a filter that traps particulate matter contained in exhaust gas of an internal combustion engine. The regeneration method includes increasing an amount of soot having a low degree of graphitization in the filter. After the amount of soot having the low degree of graphitization is increased, a temperature of the filter is increased.

Method for regenerating exhaust gas purifying filter apparatus

In exhaust gas purifying apparatus and method for an internal combustion engine, an abnormality determination of an NOx (Nitrogen Oxides) removing catalyst is executed on the basis of output values of both of a first exhaust gas atmosphere detecting section and a second exhaust gas atmosphere detecting section (for example, oxygen concentration sensors interposed in an exhaust passage of the engine between inlet and outlet portions of the NOx removing catalyst) from a time at which an output value of the first exhaust gas atmosphere detecting section is varied to a first predetermined value to a time at which the output value of the second exhaust gas atmosphere detecting section is reached to a second predetermined value when an exhaust gas atmosphere varying section (control unit) increases the ratio of a reducing agent in the exhaust gas.

Exhaust gas purifying apparatus and method for internal combustion engine

An exhaust gas purifying system of the present invention comprises a first catalyst which contains a noble metal and reduces hydrocarbons contained in exhaust gas, and a second catalyst which is disposed downstream of the first catalyst and contains &#x3b2;-zeolite. In the exhaust gas purifying system, a mixed gas having an air-fuel ratio of not less than 25 is burned in an internal combustion engine, and the internal combustion engine discharges the exhaust gas having an oxygen concentration of not less than 4% continuously or intermittently.

An exhaust gas purifying system for a vehicle includes a hydrogen enriching device that increases a component ratio of hydrogen with respect to reducing gas components in exhaust gas, a NOx treating catalyst and a HC trap catalyst. The hydrogen enriching device, the NOx treating catalyst and the NOx treating catalyst are arrayed in this order in the exhaust gas passageway.

An exhaust gas purifying system for an internal combustion engine of an automotive vehicle. The exhaust gas purifying system comprises an exhaust gas composition regulating device for producing a low HC concentration reducing agent in a lean exhaust gas atmosphere where air-fuel ratio is leaner than a stoichiometric value. The exhaust gas composition regulating device is disposed in an exhaust gas passageway of the engine. The low HC concentration reducing agent is low in concentration of hydrocarbons to have an exhaust gas composition having a volume ratio of NOx/HC not less than 50 in the exhaust gas passageway immediately downstream of the exhaust gas composition regulating device. Additionally, a NOx treating catalyst is disposed in the exhaust gas passageway and located downstream of the exhaust gas composition regulating device. The NOx treating catalyst is arranged to reduce NOx in the presence of the low HC concentration reducing agent supplied from the exhaust gas composition regulating device. The exhaust gas composition of the low HC concentration reducing agent is obtained in the exhaust gas passageway immediately upstream of the NOx reducing catalyst.

Growing community of inventors

Yokosuka, Japan

Hitoshi Onodera