Catalytic Converter - Overview

The warm up three way catalytic converter (WU-TWC) and the under-floor three way catalytic converter (under-floor TWC) convert hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO 2), nitrogen (N 2), and water vapor. The WU-TWC is attached directly under the cylinder head that is integrated into the exhaust manifold.

WU-TWC (Attached to the cylinder head) 

Courtesy of HONDA, U.S.A., INC.

UNDER-FLOOR TWC 

Courtesy of HONDA, U.S.A., INC.