What is the main purpose of an automotive power supply filter?

General Purpose Power Line Filters: Available in a variety of termination and mounting styles, EMI power filters with current ratings from 0.5 to 80 amps are suitable for controlling EMI emissions or susceptibility in many applications.

Industry Use: In actuators, battery charging systems, computers and accessories, fitness equipment, industrial equipment and controls, medical equipment, motors, security systems, test and measurement equipment, TV/audio/video, and other industry equipment.