In recent years, you may have heard of cars that need their first tune-up at 100,000 miles. One of the technologies that enables this long maintenance interval is the distributorless ignition.
The coil in this type of system works the same way as the larger, centrally-located coils. The engine control unit controls the transistors that break the ground side of the circuit, which generates the spark. This gives the ECU total control over spark timing.
Systems like these have some substantial advantages. First, there is no distributor, which is an item that eventually wears out. Also, there are no high-voltage spark-plug wires, which also wear out. And finally, they allow for more precise control of the spark timing, which can improve efficiency, emissions and increase the overall power of a car.
For more information on ignition systems and related topics, check out the links on the next page.