US Patent 7966862 Electrode structure for particulate matter sensor

A particulate matter detector formed in an insulated device such as a spark plug. The insulated device has a center electrode having a first end and a second end. The first end of the center electrode passes through the insulated device and may be connected to a terminal. The second end of the electrode is formed to provide a greater surface area. The form may be a star, circle, series of S's or a helix to increase the surface area of the second end of the center electrode that may be exposed to the exhaust from an engine. The sensor may be used to measure particulate matter in the exhaust of an engine and permit a processor to regulate the operation of the engine.