Toyota Jidosha Kabushiki Kaisha

Takekazu Itoh

Shunsuke Toshioka

Tomihisa Oda

Yutaka Tanai

Kazuhiro Itoh

Satoshi Watanabe

Yoshitaka Nakamura

In an internal combustion engine, an NOselective reducing catalyst is arranged in an engine exhaust passage. Urea is fed in the NOselective reducing catalyst, ammonia generated from this urea is adsorbed at the NOselective reducing catalyst, and the NOcontained in the exhaust gas is selectively reduced mainly by the adsorbed ammonia. An NOsensor able to detect NOand ammonia contained in the exhaust gas is arranged in the engine exhaust passage downstream of the NOselective reducing catalyst. It is judged that the amount of adsorption of ammonia at the NOselective reducing catalyst is saturated based on the detection value of the NOsensor when the feed of fuel to the engine is stopped during the deceleration operation.

Exhaust purification device of an internal combustion engine

In an internal combustion engine, an NOselective reduction catalyst is arranged in the engine exhaust passage, and a urea aqueous solution feed valve is arranged in the engine exhaust passage upstream of the NOselective reduction catalyst. Based on the detections results of an NOpurification rate detecting means for detecting the NOpurification rate by the NOselective reduction catalyst, a urea aqueous solution feed amount detecting means for detecting the amount of feed of the urea aqueous solution, and a urea aqueous solution concentration detecting means for detecting the concentration of the urea aqueous solution, abnormalities in the NOselective reduction catalyst, urea aqueous solution feed system, and urea aqueous solution are judged.

Exhaust purification device of internal combustion engine

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.

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Toyota, Japan

Takekazu Itoh