Toyota Jidosha Kabushiki Kaisha

Hino Motors, Ltd.

Yutaka Tanai

Shunsuke Toshioka

Tomihisa Oda

Takekazu Itoh

Satoshi Watanabe

Shinya Sato

Kazuhiro Itoh

Taro Aoyama

Yoshitaka Nakamura

Shinya Asaura

Takaharu Shimizu

Haruyuki Yokota

Takahiko Hayashi

Hiroyuki Ninomiya

Masahiko Yabe

An exhaust emission control device including a selective reduction catalyst; urea water as reducing agent being added in the pipe upstream of the reduction catalyst depurate NOthrough reduction; an oxidation catalyst arranged in the pipe upstream of an added position of the urea water, the oxidation catalyst physically adsorbing NOin the exhaust gas at a temperature lower than a lower active limit temperature of the reduction catalyst and discharging the adsorbed NOat a temperature higher than a lower active limit temperature of the oxidation catalyst; and a fuel injection device for adding fuel into the exhaust gas upstream of the oxidation catalyst is disclosed. The start of the fuel addition by the fuel injection device is refrained until exhaust temperature on an inlet side of the reduction catalyst is increased to a preset temperature comparable with the lower active limit temperature of the oxidation catalyst.

Exhaust emission control device

In an internal combustion engine, an NOselective reduction catalyst () is arranged in an engine exhaust passage, an aqueous urea solution is fed to the NOselective reduction catalyst () and the ammonia generated from the aqueous urea solution is made to be adsorbed at the NOselective reduction catalyst (), and the adsorbed ammonia is used to selectively reduce NO. At the time the engine is stopped, when the ammonia adsorption amount at the NOselective reduction catalyst () is smaller than a predetermined target amount of adsorption, the urea necessary for making the ammonia adsorption amount at the NOselective reduction catalyst () the target amount of adsorption is fed to the NOselective reduction catalyst () at the time the engine is stopped.

Exhaust purification device of internal combustion engine

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

An internal combustion engine wherein when an aqueous urea solution should be fed from an aqueous urea solution feed valve (), a feed pump () is operated forward and aqueous urea solution in an aqueous urea solution tank () is fed through an aqueous urea solution feed passage () into the aqueous urea solution feed valve (). When ceasing the feed of aqueous urea solution from the aqueous urea solution feed valve (), the feed pump () is operated in reverse whereby the ammonia gas generated in the aqueous urea solution tank () is drawn through a ammonia gas feed pipe () into the aqueous urea solution feed passage (). Next, when the feed pump () is operated forward, the ammonia gas drawn into the aqueous urea solution feed path () is ejected from the aqueous urea solution feed valve ().

Aqueous urea solution feed 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.

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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Susono, Japan

Yutaka Tanai