Exhaust purification device of internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsShunsuke Toshioka, Tomihisa Oda, Yutaka Tanai, Shinya Asaura
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Abstract
In an internal combustion engine, an NOx selective reduction catalyst (15) is arranged in the engine exhaust passage, and the amount of deposition of the HC deposited at the NOx selective reduction catalyst (15) is estimated. When the estimated HC deposition amount exceeds a predetermined allowable deposition amount, the NOx selective reduction catalyst (15) is raised in temperature to make the deposited HC desorb from the NOx selective reduction catalyst (15), and thereby the NOx selective reduction catalyst (15) from HC poisoning is restored.
Claims5
An exhaust purification device of an internal combustion engine arranging an NOx selective reduction catalyst in an engine exhaust passage, feeding urea to said NOx selective reduction catalyst, and using ammonia generated from the urea to selectively reduce NOx contained in exhaust gas, wherein HC deposition estimating means for estimating an amount of HC deposited at said NOx selective reduction catalyst is provided, and a temperature of the NOx selective reduction catalyst is raised to make deposited HC desorb from the NOx selective reduction catalyst when an amount of deposition of HC estimated by the HC deposition estimating means exceeds a predetermined allowable deposition amount, and thereby restores the NOx selective reduction catalyst from HC poisoning.
Dependencies are inferred from the claim text.