What is the function of the secondary air pump?

1 Answers
James
07/29/25 11:44pm
The function of the secondary air pump is to supply air to the three-way catalytic converter when the engine is cold, utilizing the exhaust gases to encounter oxygen in the air for secondary combustion. This raises the temperature of the three-way catalytic converter, allowing it to reach operating temperature sooner, thereby reducing harmful substances in the exhaust and serving an environmental protection purpose. The secondary air system is one of the external purification devices used to reduce exhaust emissions. By introducing additional air into the exhaust, it increases the oxygen content, enabling unburned harmful substances such as carbon monoxide and hydrocarbons to combust again under high-temperature conditions. When a vehicle's emission standards meet EU3 or EU4 requirements, it is mandatory to equip the secondary air system as an external purification device to reduce harmful emissions during the cold start phase of the engine.
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