Transition from Magnetos to Ignition Coils in Modern Cars and Motorplanes

In modern cars and motorcycles, magnetos have largely been replaced by more advanced ignition systems, particularly ignition coils and distributor-less ignition systems (DIS). Here’s a breakdown of the transition:

Magnetos

Definition

Magnetos are self-contained ignition systems that generate electricity using permanent magnets. While still used in some small engines, such as lawn equipment, they are more commonly found in motorcycles and small gasoline engines due to their simplicity and reliability.

Usage

Despite their advantages, magnetos are less common in modern automotive and motorcycle engines. They are still found in some small engines and older motorcycles, but are no longer the primary choice for most applications due to evolving technology.

Ignition Coils

Function

Ignition coils, also known as igniters or spark coils, are components that transform the battery's low voltage into the high voltage needed to create a spark at the spark plugs.

Advantage

They offer several advantages over magnetos. Ignition coils allow for more precise control over the ignition timing, improving efficiency, performance, and emissions. The consistent spark allows for optimal combustion, leading to better fuel efficiency and lower emissions.

Modern Systems

Distributor-less Ignition Systems (DIS)

Distributor-less ignition systems use multiple coils and do not require a distributor. This results in more efficient ignition and better overall performance. In DIS systems, each spark plug is controlled by its own separate coil, providing a cleaner and more reliable spark.

Spark Plug Technology

Advances in spark plug technology and ignition timing further enhance engine performance and fuel efficiency. Newer spark plugs are designed to ignite the fuel-air mixture at the optimal time, contributing to more efficient combustion and better engine performance.

Conclusion

While magnetos are still used in specific applications, the trend in modern automotive and motorcycle engines is towards ignition coils and more sophisticated ignition systems for improved performance and reliability. The shift away from magnetos is part of a broader trend towards more advanced and efficient technology.

For aircraft, the situation is different. Airplanes often use two igniters per cylinder, each firing different pistons. This ensures reliable ignition in various operating conditions. In contrast, cars and motorcycles generally use a single ignition system per cylinder. While there are cases where a single spark plug might fail, the overall system is designed to handle such situations efficiently.

Technical Considerations

In cars, a vehicle without a battery will often use a magneto. This is common in drag racing and lawn mowers. However, magnetos have a limited RPM range in which they are efficient. Modern vehicles, which rev from idle to 5000 RPM, find magnetos less effective. Additionally, the spark strength of magnetos is RPM-dependent. At low RPM, the spark is weaker, leading to poor power performance.

In aircraft, reliability is paramount. Having two magneto systems per cylinder provides redundancy and ensures that if one system fails, the other can take over. This is why two separate magneto systems are used in aircraft, ensuring reliable ignition during flight.