I have problems to configure knock control. Engine is 20XE Opel with little too high CR for RON98 and stock cams.
Engine like knocking under some circumstances. We lower engine temperature from 95-100C° to 80-85C°. It helps a lot.
But anyway there is danger. So I spend a day for knock sensing. Find frequencies by analyzing wav files, finding what means variables across wiki, Robs and Andrey forums. My frequency is 5.9kHz and 12kHz as harmonic. Try both with similar results.
But there is big problem that I can solve: when knock occurs (very easy to hear) spikes come in both knockvalue and knocknoise. No matter how to configure window and then integrator time constants. Due this KnockDiff not changes significant. KnockDiff only becomes more noisy - not unusual at normal combustion too. But not give clear rising.
For better analyze I even modify vemsV3.ini by adding Knocnoise and Knocvalue for datalogging.
I use Specrtogram for analyzing wav, where real knock recorded. Center of spots are my mentioned frequencies.
If frequency is chosen totally wrong, KnockNoise and KnockValue must not rising when knock occurs. But in real life there are big spikes during knocking on both. As I understand spikes is output buffered with given frequency only.
Currently 1.1.27 firmware.
Board #1437
Engine - slightly overbored 20xe. 86mm is standard bore.
Msq
http://www.vems.hu/files/GintsK/Config.txt
http://www.vems.hu/files/GintsK/tables.txt
Record of real knock:
http://www.vems.hu/files/GintsK/KNOCK4.wav
Not very usable wav of clicking wrench at diferent areas of block:
http://www.vems.hu/files/GintsK/wrench01.wav
One more observation: if chose knock window start at 0° and length 60° there is no Knockdiff at all - 1.00 all the time.
During experiments I found knock settings in LADA OE calibrations. Generaly window starts @ 6-18° and ends @30-42° at low rpm and @54-60° at high rpms (not window length, but end angle BTDC).