A team from Villanova University is proposing a new method for optimizing the knock threshold; the method, presented in a paper in the International Journal of Engine Research, significantly improved the closed loop performance of a standard knock controller.
Traditional approaches assume that in order to control potentially damaging knock events, it is necessary to use thresholds set to detect such events. The proposed new method takes a more stochastic view and sets the threshold such that it maximizes the sensitivity to changes in the knock intensity distribution.—Jones et al.
Using their method to optimize the threshold and controller parameters resulted in a controller with fast transient response, improved mean spark advance, and reduced cyclic dispersion.
With no modifications other than optimizing the parameters of a standard controller, it is therefore possible to operate closer to the knock limit, thereby improving fuel efficiency, emissions, and output torque.—Jones et al.
James C Peyton Jones, Jill M Spelina, Jesse Frey (2014) “Optimizing knock thresholds for improved knock control,” International Journal of Engine Research vol. 15 no. 1 123-132 doi: 10.1177/1468087413482321