Secondary Air Injection

Secondary Air Injection: An Overview

What is Secondary Air Injection?

Secondary air injection (SAI) is an emissions control technology that injects fresh air into the exhaust system of an engine. This air helps to oxidize unburned hydrocarbons (HC) and carbon monoxide (CO) in the exhaust, reducing harmful emissions released into the atmosphere.

Why is a Secondary Air System Used?

Secondary air injection systems are used to meet strict emissions regulations. By reducing HC and CO emissions, SAI systems help to improve air quality and reduce the impact of vehicles on the environment.

Structure of the Active Secondary Air System

An active secondary air system typically consists of the following components:

• Air injection driver: Controls the operation of the air injection system.
• Air pump: Supplies fresh air to the exhaust system.
• Air switching valve: Directs air into the exhaust manifold.

Function of the Active Secondary Air System

The active secondary air system operates during the warm-up phase of the engine. When the engine is cold, the air injection driver activates the air pump, which forces fresh air into the exhaust manifold. This air helps to oxidize HC and CO in the exhaust, reducing emissions.

Legal Requirements for Secondary Air Injection Systems

In many countries, secondary air injection systems are required by law for vehicles that meet certain emissions standards. These regulations vary by country and region, so it's important to check the specific requirements for your vehicle.

Can a Car Run Without a Secondary Air Injection System?

Some vehicles may be able to run without a secondary air injection system, but it is not recommended. Without SAI, the vehicle may not be able to meet emissions regulations and could produce higher levels of HC and CO emissions.

Conclusion

Secondary air injection systems play an important role in reducing emissions from vehicles. By understanding the structure and function of these systems, you can help to ensure that your vehicle is operating properly and meeting emissions standards.