[Diy_efi] Crank sensor for knock detection?

[Mike]

I take you are talking instantaneous changes in rotational
velocity, from what i can recall on this subject from some
years back - the classic CAS has too little resolution
coupled with mechanical slop (for the dizzy CAS) and DSP
computational requirements (cost) precluded use on most common
vehicles - maybe for the higher luxury models, but whats
wrong with a microphone and FFT, gain selective with
respect to engine revs/load, also how would one
account for changes to rotational torque to feed into
CAS instantaneous changes over the life of the engine,

Honda went to some trouble with their ring gear brushless
servo motor to smooth out the instantaneous torque
fluctuations and I dont recall any knock detection but,
then it wasnt considered a performance model - 'prious'?
I think - the battery/hybrid on sale in Australia.

On my Nissan RB30 block there are 3 knock sensor tapped
locations between the relevant cylinders, though only
one of them is used for my ECU. I'm told the current block
is good for 1200hp without major mods as it already comes
with a big end cap girdle around all 7 mains.
Knock sensors are cheap and
three off for an engine like that might well be more
reliable than CAS given torque fluctuations will differ
from one end of the crank to the other !

rgds

mike



At 11:35 AM 3/12/03 -0600, you wrote:
>Ok, too much sour mash, the question was supposed to be was it possible
>to use the crank sensor to detect detonation in an engine...
>
>Yeah knock sensor for knock detection is easy, lol.  What about
>analyzing the crank sensor waveform in real time to detect detonation.
>Is it possible, and is it done on production engines that don't come
>with knock sensors?
>
>Thanks
>
>Mike
>
>
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org 
>> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of PuffnSmoke
>> Sent: Wednesday, March 12, 2003 2:54 AM
>> To: 'List for general do-it-yourself EFI talk'
>> Subject: [Diy_efi] Crank sensor for knock detection?
>> 
>> 
>> Is it possible to use the knock sensor for detecting knock in 
>> an engine?
>> How to the PCM/ECM's on knock-sensorless engines handle 
>> ignition timing
>> when knock occurs?
>
>
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