Why Does My Car Have Multiple Catalytic Converters?

by Andrea Stein

Catalytic converters refer to devices used to reduce emissions in internal combustion engines. Many cars come standard with one catalytic converter. Some cars may possess multiple catalytic converters to meet emission regulation standards.


Catalytic converters use a catalyst, typically platinum, palladium or rhodium, to induce a chemical reaction in the toxic emissions released by the engine. This chemical reaction neutralizes the toxins, allowing them to vent into the atmosphere safely.

Dual Exhaust

Standard cars contain an exhaust system, or a set of pipes that guides exhaust gases away from the combustion in the engine. Each exhaust typically works in conjunction with one catalytic converter. Cars with dual exhaust systems carry two catalytic converters, one to neutralize the emissions that emit from each set of pipes.

Emission Qualifications

Some modern and high-end cars follow more stringent emission qualifications, which require additional neutralization of toxic emissions. In such systems, one catalytic converter performs standard converter functions, and a second converter sends out a chemical mixture that neutralizes any residual harmful toxins before they vent out.

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