Catalytic Converter System Description - Overview

WU-TWC (Attached to the cylinder head) (for L4 engine) 

The three way catalytic converter (TWC) converts hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO2), nitrogen (N2), and water vapor. The TWC is attached directly under the cylinder head that is integrated into the exhaust manifold.

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

WU-TWC (Attached to the cylinder head) (for V6 engine) 

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 (CO2), nitrogen (N2), and water vapor. The WU-TWC is attached directly under the each cylinder head that is integrated into the exhaust manifold.

WU-TWC 

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

Under-Floor Three Way Catalytic Converter (Under-Floor TWC) 

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