Exhaust

A catalytic converter is a device in the exhaust pipe of a car, near its engine. It is used to clean up the exhaust the car sends out into the atmosphere. It works by using a catalyst material, usually made of Platinum, Palladium, and Rhodium. It converts carbon monoxide, hydrocarbons, and nitrogen oxides, all of which make the air dirty and make people sick, into carbon dioxide, water, and Nitrogen, all of which are less harmless. These chemicals, however, are still large contributors to global warming. A catalytic converter reduces carbon monoxide by contacting it with oxygen, creating carbon dioxide, which is less harmful. Because hydrocarbons are unburned fuel particles, they burn up in the catalytic converter, making it very hot.

The first widespread introduction of catalytic converters was in the United States automobile market. To comply with the U.S. Environmental Protection Agency’s stricter regulation of exhaust emissions, most gasoline-powered vehicles starting with the 1975 model year must be equipped with catalytic converters. These “two-way” converters combined oxygen with carbon monoxide (CO) and unburned hydrocarbons (HC) to produce carbon dioxide (CO2) and water (H2O). In 1981, two-way catalytic converters were rendered obsolete by “three-way” converters that also reduce oxides of nitrogen (NOx); however, two-way converters are still used for lean-burn engines. This is because three-way-converters require either rich or stoichiometric combustion to successfully reduce NOx.

Many vehicles experiencing restricted exhaust or failed emissions simply need to have the catalytic convert replaced. It is part of the exhaust and emissions control system.