What Is the Purpose of a Car Air Filter?

by Jason Medina

All cars have air filters, which are a necessary adjunct to proper engine operation. What follows is a brief description of the most basic purposes of a car air filter.

Filter Outside Air

The main purpose of an automotive air filter is to filter and clean outside air before it gets sucked into a car engine and burned along with fuel to produce combustion.

Protect Vehicle Engine

Air that gets sucked into a car engine needs to be as clean as possible to prevent engine contamination and, in some cases, engine damage. An air filter is the main line of defense against preventing damaging particulate matter from entering a vehicle's engine. Dirty air can reduce engine efficiency and cause damage; an air filter prevents this.

Protect Carburetor/Fuel Injection System

A carburetor or fuel injection system is responsible for injecting both gas and air into an engine's cylinders, a combination more commonly referred to as an engine's air/fuel mixture. Both carburetors and fuel injection systems use tiny portals and valves to function. Any debris or obstruction that enters these portals and valves can cause serious malfunction and/or damage. An engine air filter protects these delicate parts by filtering incoming air before it enters a carburetor or fuel injection system.

Increase Fuel Economy

A clean, properly installed and functioning air filter increases both engine performance and gas mileage. By filtering incoming air into an engine, an air filter ensures that air burned inside of an engine is as clean as possible. Clean, purified air ignites quicker and better inside of an engine cylinder, an occurrence that increases engine combustion efficiency, which increases fuel economy.

Augment Carburetor/Fuel Injection Function

As air gets sucked into a car's engine, it must first pass through the air filter before it reaches either the carburetor or fuel injection system, which is in charge of combining incoming air with gasoline, a combination that creates an engine's air/fuel mixture. A dirty air filter obstructs air flow and limits the amount of air that reaches the carburetor or fuel injection system, either of which responds by reducing the amount of gas injected into the air. A clean air filter augments carburetor/fuel injection function by maintaining an adequate amount of air flow.

About the Author

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us.