Ignition systems are older than the automobile itself, dating back to the 1870's. A brief history of ignition systems is presented. The use of a microencapsulated powder metal core for an ignition system is a relatively new idea. It was first introduced into an automotive system in 1990.
Microencapsulation of each iron particle with an insulating binder allows a P/M part to be pressed which, at lower frequencies, has the magnetic flux and eddy current losses similar to a laminated part.
Warm pressing, along with microencapsulation, makes a molded product which has much higher green strength and green density, as well as increased flowability during molding. This allows thin walled parts and parts with a more complex geometry to now be made by net shape P/M techniques.
Microencapsulated P/M cores have definite advantages and disadvantages over laminated cores. The design of the product and the system must be tailored to take advantage of the strengths and minimize the weaknesses of the P/M core.
The microencapsulated iron P/M technology will be used in the future coil at cylinder and the fully integrated coil/plug assemblies because of the design and performance advantages as well as lower system costs.