EXHAUST GAS CLEANING DEVICE

摘要

PROBLEM TO BE SOLVED: To solve the problem that unburned fuel is generated and may be accumulated in a lean NOx cleaning catalyst in any light oil injection heat deterioration and sulfur poisoning of the lean NOx cleaning catalyst are caused by combustion of the unburned fuel accumulated on the lean NOx cleaning catalyst although light oil is needed to be injected into an engine cylinder or into a lean exhaust gas in the case of enriching an exhaust gas flowing in the lean NOx cleaning catalyst in an internal combustion engine.

SOLUTION: The problem can be solved by locating an oxidizing agent for the unburned fuel at the upstream of a sulfur catching material. The oxidizing agent for the unburned fuel possesses the function of burning the unburned fuel contained in an exhaust gas. The sulfur catching material containing an alkali metal compound and/or an alkali earth metal compound as the main components catches the sulfur content contained in the exhaust gas and does not leave the once-caught sulfur content substantially by using a material which catches and does not discharge sulfur substantially as a part or the whole of the carrier.

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