Analysis of SI Combustion Diagnostics Methods Using Ion-Current Sensing Techniques

Development and Experimental Validation of an Adaptive, Piston-Damage-Based Combustion Control System for SI Engines: Part 1—Evaluating Open-Loop Chain Performance

“…Standard knock control strategies typically use signals coming from an on-board compatible system for knock intensity sensing (accelerometers or Ionization current-based, ION) and move spark advance at every time step. Spark timing is advanced whenever the intensity is lower than the threshold, while it is retarded when knock occurs, by applying fixed corrections [5][6][7][8][9][10][11][12][13]. Moreover, in some cases SA maps are calibrated to maintain knock intensity under the threshold for nominal operating conditions (environmental temperature, fuel Research Octane Number, RON, and so on), and by using the knock controller just to retard SA when the on-board system senses "high" intensity knocking events, according to defined spark timing correction maps [14].…”

“…As mentioned above, once the log-normal PDF that fits the integral value over the MAPO threshold calculated by the knock model is identified through Equation ( 15), the corresponding value of a MAPO percentile (98th in this case) can be used by the knock model as input. Such algorithm uses the linear function between two percentiles of a log-normal distribution introduced in the Appendix in [11] and reported in Equation ( 16):…”

Linear Regression and its Use in Predicting the Link Between Ionization Current and the Pressure Signal in a Hybrid Mode Engine

“…The most obvious feedback signal to use would be a cylinder pressure sensor; development of reliable, low cost and accurate sensors for long term use is ongoing. It has been recently documented [4,5,6] that the Ionisation Current (IC), measured within the cylinder has several characteristics which relate to an in cylinder pressure sensor.…”