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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsShinichi Takeshima, Kiyoshi Nakanishi, Satoshi Iguchi, Toshiaki Tanaka, Yasushi Araki, Shinya Hirota, Kiyoshi Kobashi
Estimating the term…
An NO.sub.x absorbent (18) is disposed in an exhaust passage of an internal combustion engine and the exhaust gas is constantly made to circulate through the NO.sub.x absorbent (18) during the operation of the engine. The NO.sub.x absorbent (18) absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (18) 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 (18) becomes the stoichiometric air-fuel ratio or rich. In the majority of the engine operation region, the lean air-fuel mixture is burned in the combustion chamber (3), and the NO.sub.x generated at this time is absorbed into the NO.sub.x absorbent (18). The air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (18) is periodically made the stoichiometric air-fuel ratio or rich, and the NO.sub.x absorbed in the NO.sub.x absorbent (18) is released, and simultaneously reduced.
An exhaust purification device of an internal combustion engine including an exhaust passage and means for controlling an air-fuel ratio of exhaust gas from the engine, comprising an NO.sub.x absorbent disposed within the exhaust passage, wherein the NO.sub.x absorbent absorbs NO.sub.x included in the exhaust flowing into the NO.sub.x absorbent when the air-fuel ratio control means makes the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent lean and releases an absorbed NO.sub.x when an oxygen concentration in the exhaust gas flowing into the NO.sub.x absorbent is lowered, and wherein, at all times while the engine is running, the exhaust gas continuously flows into the NO.sub.x absorbent so that the NO.sub.x absorbed in the NO.sub.x absorbent while the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent is lean is released from the NO.sub.x absorbent when the oxygen concentration of the exhaust gas flowing into the NO.sub.x absorbent is lowered.
Dependencies are inferred from the claim text.