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How does a catalytic converter reduce harmful engine exhaust emissions?
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diesel engine
Diesel engine equipped with a precombustion chamber.
A catalytic converter reduces harmful engine exhaust emissions by passing exhaust gases through an insulated chamber containing a honeycomb structure or ceramic pellets coated with catalysts, such as platinum and palladium.12
As the exhaust gases flow through this structure, the catalysts trigger chemical reactions that transform pollutants into less harmful substances:
- Oxidation: Hydrocarbons and carbon monoxide are oxidized into water vapour and carbon dioxide.12
- Reduction: Nitrogen oxides are reduced into nitrogen and oxygen.12
These systems are a critical component of emission control systems designed to limit the discharge of noxious gases from internal-combustion engines. However, they are not fully effective during engine warm-up, as the catalysts require higher temperatures to function efficiently.12