Dual Catalytic Converter

This converter assembly consists of two separate converters in one shell, with a mixing chamber in between. The forward converter is designed to control all 3 major emissions (NOx, HC, CO), and is therefore called a 3-way catalyst. The rear converter is a conventional oxidation catalyst and controls only HC and CO.

As gases flow out of the 3-way catalyst, they mix with air from the air pump system. This mixing is required to allow the rear converter to properly control HC and CO emissions.