EXHAUST GAS CLEANING DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To solve the technical problem that an alkali metal in a lean NOx catalyst has such properties as to move by heat from the inside of a catalyst layer to a cordierite substrate and causes a decrease in the quantity of the alkali metal in the catalyst layer to degrade the catalytic performance.

SOLUTION: In the exhaust gas cleaning device, the resistance to movement of an alkali metal is enhanced by decreasing the contact area between a catalyst layer and cordierite, decreasing the quantity and speed of alkali movement. Thus, erosion caused by the movement of an alkali to the substrate is prevented, and the cleaning capability is increased by increasing the quantity of an alkali metal carried by the substrate.

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