Red Seal Automotive Service Technician Practice Exam

How does a catalytic converter work?

1. By filtering out fuel vapors

2. By using chemical reactions to reduce harmful emissions

3. By heating the exhaust gases

4. By converting energy into electricity

The correct answer is: By using chemical reactions to reduce harmful emissions

A catalytic converter works primarily by utilizing chemical reactions to reduce harmful emissions from the engine's exhaust gases. Inside the converter, there are precious metals like platinum, palladium, and rhodium that act as catalysts. These metals facilitate reactions that convert harmful substances in the exhaust, such as carbon monoxide, hydrocarbons, and nitrogen oxides, into less harmful substances like carbon dioxide and nitrogen. The process relies on two main types of reactions: oxidation and reduction. In the oxidation process, carbon monoxide is transformed into carbon dioxide, while in the reduction process, nitrogen oxides are converted into nitrogen and oxygen. This efficient handling of harmful emissions is essential for meeting environmental regulations and ensuring cleaner air. The other choices focus on different mechanisms that do not represent the primary function of a catalytic converter. Filtering out fuel vapors is not related to the catalytic converter's role in emission reduction. Heating exhaust gases isn't a function of the catalytic converter itself; instead, it relies on efficient chemical reactions occurring at specific temperatures. Lastly, converting energy into electricity is not a function of a catalytic converter, which strictly deals with the conversion of harmful substances in the exhaust stream rather than energy transformation.