DIY Ion Sensing
Turbo Mini Forums

Of use to anyone?

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I had a good read still wasn't sure so I spoke to the wife who told be the iron was upstairs in the cupboard.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

follwed the old thread on msefi.com with interest. will read this, thanks for the find:) always been soemthign i have been keen to impement due to my love of on-road tuning.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

bet all that analysis could be done in matlab on a decent laptop ( i pissed around with matlab to analyse a microphone on the block to detect knock, but found my ears every bit as accurate lol) it did work though. intrigued.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

hmmm

certainly interesting,

http://www.trionicsuites.com/Data/manuals/Trionic%205.pdf

Have you been reading the MS forums ?

Very interesting stuff.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

yep, thats where i got the link from

Bloody clever stuff:

Lifted from ^^^^ report for ease of reference.

"The Trionic system lacks a camshaft position sensor. This sensor is normally a prerequisite for a
sequential pre ignition/pinging regulation and fuel injection. Saab Trionic must decide whether
cylinder one or cylinder four ignites when the crank shaft position sensor indicates that cylinder one
and four is at TDC. This is done by the help of ionization current, one of the poles of the secondary
coil of the spark coils is connected to the spark plugs in an ordinary manner. The other pole isn’t
grounded directly but connected to an 80 V voltage. This means that an 80 V voltage is fielded over
the spark gap of the spark plugs, except when the spark is fired. When combustion has occurred the
temperature in the combustion chamber is very high. The gases are formed as ions and start to
conduct electrical current. This results in a current flowing in the spark plug gap (without resulting in
a spark). The ionization current is measured in pair, cylinder one and two is one pair and cylinder
three and four in the other pair. If combustion occurs in cylinder one or two the ignition cassette is
sending a battery voltage (B+) pulse to the ECU, pin 17. If the combustion takes place in cylinder
three or four the B+ pulse is feed to pin 18 in ECU. If the crankshaft position sensor is indicating that
cylinders one and four is at TDC and a B+ pulse enters the ECU via pin 17 simultaneously, then the
ECU know that it is cylinder one that has ignited. At start the ECU doesn’t know which cylinder is in
the compression stroke. Ignition is initiated in both cylinder one and four and 180° crank shaft
degrees later sparks in cylinder two and three are fired. As soon as combustion signals enters the ECU
via pin 17 and pin 18 the ignition and fuel injection is synchronized to the engines firing order. The
combustion signals are also used to detect misfires."

Also:

"During engine operations the Ignition cassette continuously monitors the ion currents in the cylinders
and sends a signal to the Trionic ECU on pin 44, in the event of knocking. The logic for this function
rests solely in the ignition cassette and is adaptive to be able to handle disturbing fuel additives. The
Trionic ECU is well aware of which cylinder that has ignited and could hence cope with the information
fed through one pin. The signal to pin 44 and ion current in the combustion chamber is related to
each other. When this signal reaches a certain level the ECU interprets this as a knocking event and
firstly lowers the ignition advance by 1.5° on this cylinder. If the knocking is repeated the ignition
advance is lowered further by 1.5 °, up to 12°. In case of the same lowering of the ignition timing
advance in all cylinders the ECU adds a small amount of fuel to all cylinders. If knocking occurs when
the MAP is over 140 kPa the knocking is regulated by switching both fuel injection matrix and ignition
advance matrix. If this is not sufficient the charging pressure is lowered. This purpose of this
procedure is to maintain good performance. If the signal between the ignition cassette and the ECU is
lost, the charging pressure is lowered to basic charging pressure and the ignition timing advance is
retarded by 12° if a risk of knocking exists due to engine load."

Look like you need special coils like the Saab "DI Casette" plus some fancy programming in the ECU to make it work.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

interesting stuff

Yes i moved to the darkside

Instagram @jdm_brett

I think the main motivation with keeping the logic circuits in the ignition cassette is to keep all the high voltage stuff away from the ecu! ... Interestinggly, it meens that it ought to e relatively easy to retrofit the Saab cassette to any other 4 cylinder car..

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

i've got a complete saab engine sitting- happy to donate the parts if someone wants to try it out

Well you could dumb it down, have a cam sensor so the correct coils are fired, negating the sync signals, and monitor the wire to pin44 and use it as a global knock detection input :) ( the article implies this is a good ol 0-5 v analogue signal where the voltage represents combustion event Vs crank angle, anythin below 14 deg atdc ( which will be represented by a voltage) should flag knock! .. Could be a pwm signal too but the premise is the same! ,. Wish I had some spare dosh!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

The output could represent cylinder pressure irrespective of crank angle too actually :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.