Knock sensor processing
Posted: Tue Oct 20, 2015 11:29 am
Just about to order a MicroSquirt and do an ignition system on one of my MGBs. I am testing a Bosch knock sensor and I should be able to do the bandpass filtering. My goal is to see what I can wring out of it with the Weber DGV still there. ( EFI is stage two) This is a street car.
Assuming I can get a reliable signal, which may be a stretch on this old lump, I have lots of questions on the software as it pertains to knock sensors.
*Does it do the time windowing? I only want to look for knock a few ms after ignition.
*If I run it into one of the ADC lines, is the software already set up for the threshold detection?
*Is there any DSP capability on the ADC inputs to implement bandpass. ( I want to see 7K above a threshold for 5 cycles kind of processing)
*If I did the threshold detection in the external filter, is there a digital input or should I just use the ADC input.
*When you detect knock, you want to back off the timing a couple degrees across some mid-RPM high load area of the maps. Any ideas on this?
*When do you let it back in? Next power cycle, when the MAP goes back up? Do I just take it out and put it back one degree at a time a sew seconds later?
* Do I make the map as close as I can and just let the sensor trim under unusual situations, or do I set the map very aggressive and rely in the sense to pull it back constantly? The age old servo question, stable and trim or unstable and control.
Is there a great big FAQ somewhere that answers these and the issues I have not thought of yet? I have not found one but there are a lot of forums dedicated to the MS. I could have missed one or two.
Assuming I can get a reliable signal, which may be a stretch on this old lump, I have lots of questions on the software as it pertains to knock sensors.
*Does it do the time windowing? I only want to look for knock a few ms after ignition.
*If I run it into one of the ADC lines, is the software already set up for the threshold detection?
*Is there any DSP capability on the ADC inputs to implement bandpass. ( I want to see 7K above a threshold for 5 cycles kind of processing)
*If I did the threshold detection in the external filter, is there a digital input or should I just use the ADC input.
*When you detect knock, you want to back off the timing a couple degrees across some mid-RPM high load area of the maps. Any ideas on this?
*When do you let it back in? Next power cycle, when the MAP goes back up? Do I just take it out and put it back one degree at a time a sew seconds later?
* Do I make the map as close as I can and just let the sensor trim under unusual situations, or do I set the map very aggressive and rely in the sense to pull it back constantly? The age old servo question, stable and trim or unstable and control.
Is there a great big FAQ somewhere that answers these and the issues I have not thought of yet? I have not found one but there are a lot of forums dedicated to the MS. I could have missed one or two.