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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsShunsuke Toshioka, Tomihisa Oda, Takekazu Itoh, Yutaka Tanai, Satoshi Watanabe, Yoshitaka Nakamura
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In an internal combustion engine, an NOx selective reduction catalyst is arranged in the engine exhaust passage and a urea aqueous solution stored in a urea aqueous solution tank is fed to the NOx selective reduction catalyst where the NOx is selectively reduced. Opening and closing of the urea aqueous solution refill port of the urea aqueous solution tank are detected and it is judged if the urea aqueous solution is refilled in the urea aqueous solution tank. When it is judged that the NOx purification rate has fallen to an allowable level or less at the time of engine operation right after the urea aqueous solution is refilled in the urea aqueous solution tank, it is judged that the refilled urea aqueous solution is abnormal.
An exhaust purification device of an internal combustion engine arranging an NOx selective reduction catalyst in an engine exhaust passage, feeding a urea aqueous solution stored in a urea aqueous solution tank to the NOx selective reduction catalyst, and using ammonia produced from the urea aqueous solution to selectively reduce NOx contained in an exhaust gas, wherein urea aqueous solution refill judging means for judging if the urea aqueous solution has been refilled in the urea aqueous solution tank and NOx purification rate judging means for judging if the NOx purification rate has fallen to an allowable level or less are provided and, urea aqueous solution abnormality judging means for judging if the refilled urea aqueous solution is abnormal when it is judged that the NOx purification rate has fallen to the allowable level or less at the time of engine operation right after the urea aqueous solution has been refilled in the urea aqueous solution tank.
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