A low-complexity virtual sensor for the pressure peak position of the crank angle in a spark-ignited car motor is proposed. The algorithm estimates the pressure peak position from the ion current, measured from the spark plug. The complexity of the algorithm is an order of magnitude smaller than any other proposed schemes. Still, performance is not sacrificed. Closed-loop control is demonstrated on a SAAB 9000 driven on the highway.

Glaser, I., and Powell, J. D., 1981, “Optimal closed-loop spark control of an automotive engine,” Technical paper 810058, Society of Automotive Engineers (SAE).
Hubbard, M., Dobson, P. D., and Powell, J. D., 1976. “Closed loop control of spark advance using a cylinder pressure sensor,” Trans. ASME: J. Dyn Syst., Meas., Control, December, pages 414–420.
Powell, J. D., 1993, “Engine control using cylinder pressure: Past, present, and future,” Trans. ASME: J. Dyn Syst., Meas., Control, 115, 343–350.
Gillbrand, P., Johansson, H., and Nytomt, J., 1987, “Method and apparatus for detecting ion current in an internal combustion engine ignition system,” U.S. Patent No. 4,648,367.
Eriksson, L., Nielssen, L., and Glavenius, M., 1997, “Closed loop ignition control by ionization current interpretation,” Technical paper 970854, Society of Automotive Engineers (SAE).
Hellring, M., Munther, T., Ro¨gnvaldsson, T., Wickstro¨m, N., Carlsson, C., Larsson, M., and Nytomt, J., 1999, “Spark advance control using the ion current and neural soft sensors,” Technical paper 1999-01-1162, Society of Automotive Engineers (SAE).
Hellring, M., Ro¨gnvaldsson, T., Wickstro¨m, N., and Larsson, M., 2000, “Ion current based pressure peak detection under different air humidity conditions,” in Advanced Microsystems for Automotive Applications 2000, pages 125–138.
Hellring, M., and Holmberg, U., 2000, “An ion current based peak-finding algorithm for pressure peak position estimation,” in SAE International Fall Fuel & Lubricants Meeting & Exposition, Baltimore, Maryland USA. 2000-01-2829.
Hellring, M., and Holmberg, U., 2001,“A comparison of ion current based algorithms for peak pressure position control,” in SAE International Fall Fuel & Lubricants Meeting & Exposition, Orlando, Florida USA. 2001-01-1920.
Saitzkoff, A., Reinmann, R., Berglind, T., and Glavmo, M., 1996, “An ionization equilibrium analysis of the spark plug as an ionization sensor,” Technical paper 960337, Society of Automotive Engineers (SAE).
Saitzkoff, A., Reinmann, R., Mauss, F., and Glavmo, M., 1997, “In-cylinder pressure measurements using the spark plug as an ionization sensor,” Technical paper 970857, Society of Automotive Engineers (SAE).
You do not currently have access to this content.