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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKazuhiro Itoh, Toshiaki Tanaka, Shinya Hirota, Koichi Kimura, Koichiro Nakatani
Estimating the term…
A particulate filter (22) carrying an active oxygen release agent which takes in oxygen and holds oxygen when excess oxygen is present in the surroundings and releases the held oxygen in the form of active oxygen when the concentration of oxygen in the surroundings falls is arranged in an exhaust passage of an engine. The air-fuel ratio of the exhaust gas flowing into the particulate filter (22) is normally maintained lean and is occasionally switched to rich temporarily. When the air-fuel ratio of the exhaust gas is switched to rich, an oxidation reaction of the particulate on the particulate filter is promoted by the active oxygen released from the active oxygen release agent. Due to this, the particulate in the exhaust gas is continuously removed by oxidation on the particulate filter (22) without emitting a luminous flame.
An exhaust gas purification method comprising carrying on a particulate filter for removing particulate in exhaust gas discharged from a combustion chamber an active oxygen release agent for taking in oxygen and holding oxygen when there is excess oxygen in surrounding and releasing the held oxygen in the form of active oxygen when the concentration of oxygen in the surroundings fall, maintaining an air-fuel ratio of the exhaust gas flowing into the particulate filter normally lean and occasionally switching it temporarily to rich to promote an oxidation reaction of the particulate on the particulate filter by the active oxygen released from the active oxygen release agent when the air-fuel ratio of the exhaust gas is switched to rich, and thereby remove by oxidation the particulate on the particulate filter without emitting a luminous flame.
An exhaust gas purification method carrying on a particulate filter for removing particulate in exhaust gas discharged from a combustion chamber an active oxygen release agent/NOx absorbent for taking in oxygen and holding oxygen when there is excess oxygen in surrounding and releasing the held oxygen in the form of active oxygen when the concentration of oxygen in the surroundings fall and for absorbing NOx in the exhaust gas when an air-fuel ratio of the exhaust gas flowing into the particulate filter is lean and releasing the absorbed NOx when the air-fuel ratio of the exhaust gas flowing into the particulate filter becomes the stoichiometric air-fuel ratio or rich, maintaining the air-fuel ratio of the exhaust gas flowing into the particulate filter normally lean and occasionally switching it temporarily to rich to promote an oxidation reaction of the particulate on the particulate filter by the active oxygen released from the active oxygen release agent/NOx absorbent and reduce the NOx released from the active oxygen release agent/NOx absorbent when the air-fuel ratio of the exhaust gas is switched to rich, and thereby removing by oxidation the particulate on the particulate filter without emitting a luminous flame, and simultaneously removing the NOx in the exhaust gas.
Dependencies are inferred from the claim text.