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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsShinichi Takeshima, Yasushi Araki, Shinya Hirota
Estimating the term…
An NO.sub.x absorbent (19) is disposed in an exhaust passage of an internal combustion engine and an NO.sub.x oxidizing agent (18) is disposed in the exhaust passage upstream of the NO.sub.x absorbent (19). The NO.sub.x absorbent (19) absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (19) is lean and releases the absorbed NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (19) becomes the stoichiometric air-fuel ratio or rich. When the lean air-fuel mixture is burned, if the temperature of the NO.sub.x absorbent (19) is low, the NO.sub.x oxidized by the NO.sub.x oxidizing agent (18) is absorbed by the NO.sub.x absorbent (19), while if the temperature of the NO.sub.x absorbent (19) is high, the NO.sub.x is oxidized by the NO.sub.x absorbent (19) and absorbed in the NO.sub.x absorbent (19).
An exhaust purification device of an internal combustion engine wherein an NO.sub.x absorbent which absorbs the NO.sub.x when an air-fuel ratio of an inflowing exhaust gas is lean and releases an absorbed NO.sub.x when the oxygen concentration in the inflowing exhaust gas is lowered is disposed in an exhaust passage of the engine, an NO.sub.x oxidizing agent which can oxidize the NO.sub.x is disposed in the engine exhaust passage upstream of the NO.sub.x absorbent, and the NO.sub.x absorbed in the NO.sub.x absorbent when the exhaust gas flowing into the NO.sub.x absorbent is lean is released from the NO.sub.x absorbent by means to lower the oxygen concentration in the exhaust gas flowing into the NO.sub.x absorbent.
Dependencies are inferred from the claim text.