ignition: Interrupting the Current

In older automobiles, the interruption of the primary current was created by “breaker points,” a switch with tungsten contacts to retard erosion. Driven at half engine speed, a breaker cam, a rotating object with a lobed surface (one lobe for each cylinder), opened and closed the points. When the breaker points were closed, current flowed through the primary winding of the ignition coil. In electronic ignition systems, introduced in the early 1960s, the interrupting device is a reluctor, a magnetic pulse distributor that produces timed electric signals that are amplified to control the current to the primary winding of the ignition coil. Such systems generally reduce ignition maintenance and increase engine efficiency.

Sections in this article:

• Introduction
• Magneto and Diesel Ignition Systems
• The Spark Plug
• The Ignition Coil and Distributor
• Interrupting the Current
• Battery Ignition Systems

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2024, Columbia University Press. All rights reserved.

See more Encyclopedia articles on: Technology: Terms and Concepts