[Diy_efi] Re: Custom detonation detecting

[Andris Skulte]

This isn't accoustic, but on page 455 of Heywood's Internal Combustion
Engine Fundamentals, they run a bandpass filter on their cylinder pressure
transducer for the first transverse mode of gas vibration in the cylinder
(in 3 to 10 kHz range, depending on bore and geometry). later on page 460,
he mentiones immediately after the pressure spike, they see pressure
oscillation at the 6 to 8 kHz range... ... page 461: "The frequency of
pressure oscillations (in 5 to 10 kHz range) decreases with time as the
initially finite amplitude supersonic pressure waves decal to small
amplitude sound waves.

Andris/Z28tt

On Tue, 19 Nov 2002, Jon Prevost wrote:

> > For whatever reason, Jon wanted to detect detonation acoustically, so
> > I was steering him away from his initial choice of a Cavalier(?) knock
> > sensor as counter-productive. I suspect that after he reads the URLs,
> > he'll abandon the acoustic approach altogether.
> 
> Consider it abandoned for our project. I just found out that we have the
> tools for ion sensing and that's my major focus right now. Well that and
> finals.
> If I was going to go with the acoustic method I would have had to setup a
> lot of dry experiments and I wasn't ready to sit down, start the motor and
> record what happens to the acoustics while I "unhook" a timing chain, or cut
> fuel, etc. Too many issues to deal with. I still think it would be a fun
> project to record the general frequency range of detonation and see if there
> are any traights apparently obvious.
> Thanks for the links to the ion sensing.
> , Jon
> 
> 
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://www.diy-efi.org/mailman/listinfo/diy_efi
> 

------------------
Andris Skulte
Skulte Performance Designs
http://www.skulte.com  
Z28tt-89 IROC T56 DFI Twin Turbo


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi