AC Ion Current Interface

by Johan Nilsson

Institution: Karlstad University
Year: 2009
Keywords: Ion current; Combustion monitoring; Engineering and Technology; Electrical Engineering, Electronic Engineering, Information Engineering; Other Electrical Engineering, Electronic Engineering, Information Engineering; Teknik och teknologier; Elektroteknik och elektronik; Annan elektroteknik och elektronik; TECHNOLOGY; Electrical engineering, electronics and photonics; Electrical engineering; TEKNIKVETENSKAP; Elektroteknik, elektronik och fotonik; Elektroteknik; Electrical Engineering; Elektroteknik; teknik; teknik
Record ID: 1364519
Full text PDF: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-3473


An effective way to extract combustion parameters from a spark ignited engine is to measure the level of ionization. One way to do this is to use the spark plug as a sensor. Until now this has been achieved by applying a DC voltage over the spark gap which causes an electrical field. The electrical field together with the ionization process gives cause to an ion current which can be measured and analyzed. Previous research suggests that it would be beneficial to replace the DC voltage with an AC voltage. The focus in this thesis is on the hardware and how to best implement an AC voltage to the existing ion sensing system. Both simulation- and hardware models will be constructed. These models will be tested and analyzed to evaluate both benefits and drawbacks of an AC ion current sensing system.