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Exhaust Gas Purification System

Purpose, outline

• Purifies contaminants (HC, CO, NOx) in the exhaust gas by utilizing the chemical reactions of the three-way catalytic converter.

System diagram

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Structure

• The exhaust gas purification system consists of the following parts:

Catalytic Converter

Purpose, function

• Purifies contaminants in the exhaust gas by utilizing the chemical reactions of the three-way catalytic converter.

• A WU-TWC and a TWC have been adopted.

WU-TWC

― The three-way catalyst is integrated with the exhaust manifold.

― Because the catalyst receives the high temperature exhaust gas just after the gas is exhausted, it activates quickly and achieves an improved purification performance.

TWC

― A single-nano catalyst has been adopted in which the purification performance can be maintained using less precious metal materials than conventional catalysts.

Construction

WU-TWC

• The WU-TWC is installed to the rear of the engine.

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• The WU-TWC is integrated with the exhaust manifold.

TWC

• The TWC is installed to the rear of the WU-TWC.

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Operation

• Contaminants in the exhaust gas (HC, CO, NOx) are purified by oxidization and deoxidization while they are passing through the catalytic converter.

― Oxidization process

• Noxious hydrocarbon (HC) and carbon monoxide (CO) are bound with oxygen and converted to non-noxious carbon dioxide and water. O ₂+HC+CO→CO ₂+H ₂O

― Deoxidization process

• Noxious nitrogen oxide (NOx) is converted to non-noxious nitrogen and oxygen. A part of the oxygen generated in this process is used in the oxidization process. NOx→N ₂+O ₂