Toyota Jidosha Kabushiki Kaisha

Satomi Seto

Shinichi Takeshima

Toshiaki Tanaka

Satoshi Iguchi

Shinya Hirota

Kiyoshi Nakanishi

Kenji Katoh

Exhaust purification device of internal combustion engine

An engine comprising an exhaust passage having therein a NO.sub.x absorbent which absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent 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 becomes the stoichiometric air-fuel ratio or rich. A catalyst having an O.sub.2 storage function is arranged in the exhaust passage downstream of the NO.sub.x absorbent. When NO.sub.x is to be released from the NO.sub.x absorbent, the air-fuel ratio of the exhaust gas is made rich to an extent such that the amount of unburned HC and CO is excessive beyond an amount necessary to reduce the whole NO.sub.x.

Exhaust gas purification device for an engine

In an exhaust purification apparatus of an internal combustion engine having an NOx absorption and release material in an exhaust conduit, a heater is provided close to the NOx absorption and release material. When an NOx absorption operation continues for a predetermined period, the heater is switched on to raise the temperature of the NOx absorption and release material above a predetermined temperature, for example, 500.degree. C. When the temperature of the NOx absorption and release material is high, the NOx absorption and release material releases absorbed NOx and is regenerated.

NOx decreasing apparatus for an internal combustion engine

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Gotenba, Japan

Satomi Seto