I understand the overall ignition timing and knock control calculations, but the actual “knock control” value used in those calculations and displayed/logged as KNK.CTRL is still a bit of a mystery. On a guess I expected to see it driven by knock count, rising when knock is detected then falling quickly as knock is suppressed. What I see in the logs is a continuous series of spikes up then very gradual falls with no change in knock count. In the screenshot, red is knock count, green is knock control and light blue is intake air temp to confirm it isn’t somehow correlated (nor is coolant temp).
So, what drives the knock control value? Or is it really knock after all but that’s not being captured as an increasing count?
https://photos.app.goo.gl/J8BekVhBfF4dwupX8
Knock control value
Re: Knock control value
The knock count is a misfire monitor counter and separate from knock control. That's why everywhere you'll see knock count talked about everyone says pay attention to knock control, not count.
Re: Knock control value
Ah, not obvious, but OK. So it sounds like my interpretation of what’s shown in the logs is correct; knock it detected, knock control spikes which pulls back timing, then gradually falls until/unless knock is detected again. It does that a LOT on track even with the stock tune and premium fuel. It would be interesting to experiment with the decay slope of the knock control value but I’d guess Honda has that pretty well calibrated.
Re: Knock control value
Yes, essentially it moves toward making the most power possible for the current fuel and then backs away once it senses noise that meets the sensitivity thresholds.