Magneto Ignition Systems (1)

Magneto Ignition Systems

Table of ContentsI. Introduction to Magneto Ignition SystemsWhat are Magneto Ignition Systems?What are the different uses for the Systems?II. Different Types of SystemsMBICDITCIIII. SummaryIV. Review Questions

What are Magneto Ignition Systems?The purpose of an ignition system is to provide sufficient electrical voltage to discharge a spark plug at precisely the right time to ignite highly compressed air-fuel mixture.Magneto Ignition systems provide current for ignition without any outside primary source of electricity.

Different UsesThe primary uses for Magneto Ignition systems are in small gasoline powered engines such as lawn mowers.

Different TypesMBI Mechanical Breaker Point IgnitionCDI Capacitive Discharge IgnitionTCI Transistor Controller Ignition

Mechanical Breaker Point IgnitionOne of the types of ignition systems, the MBI system uses a Condenser to prevent current from arcing across the breaker point gap as the points open.

Advantages to MBIMBI does not require a primary source of electricity in order to produce ignition in the engine.Through the use of the Flywheel and the condenser, a continuous current is generated and can be easily broken for stopping purposes by use of the condenser.

MBI in UseImage courtesy of http://web.telia.com/~u85306919/1912.jpg

Capacitive Discharge IgnitionCDI is a solid state ignition system, it is one of the newest ignition systems used today.CDI is breakerless and the moving mechanical parts are replaced with electronic components.The only moving parts are the magnets attached to the Flywheel.

Advantages to CDICDI is very easy to troubleshoot, by turning the flywheel and watching the sparkplug gap for a spark.CDI is compact and maintenance free since the only moving parts are the flywheel magnets.

CDI in UseImage courtesy of www.dansworkshop.com

Transistor Controller IgnitionAs the Flywheel magnets rotate they pass by the ignition coil in the system.The magnetic field of the magnets induce current in the primary windings of the ignition coil creating the charge for the spark.

Advantages to TCIAs with CDI, the only moving parts are the magnets on the flywheel.The timing of TCI is more precise with the use of the Transistors.Does not use Mechanical Breaker contacts, but utilizes semi-conductors instead.

TCI in Use

SummaryThe primary purpose of the ignition system is to provide sufficient voltage to discharge a spark plug.The three types of Magneto Ignition systems have advantages over the others but have different uses for each.Small engines most prominently use Magneto Ignition Systems for firing the ignition of the engine.

Image courtesy of http://home.howstuffworks.com/how-to-repair-small-engines3.htm

Review Questions1. Name three components of a CDI system.2. What is the main purpose of the Condenser?3. Which of the systems has the least amount of maintenance?4. In the CDI system, what is the only moving part?

Review Questions cont.5. What is the main purpose of an Ignition System?6. What does TCI stand for and what makes it different from the rest?7. What is an advantage to using an MBI system? 8. How can you troubleshoot a CDI system?

References Roth, Alfred C. Small Gas Engines. Tinley Park: The Goodheart-Willcox Company, Inc., 2004.