EFI: Megasquirt question (future product)

[cowtown]

I know a few of you have researched the Megasquirt, which controls fuel but not ignition. I have a question about the next generation:

Their site states:
"...we are currently developing a multiple-coil CDI ignition system with ion-sensing technology which will interface directly to the MegaSquirt system - stay tuned..."

Does anyone have more information about this next product, either technical details or timeframe?

Thanks
Colin

[beepbeep]

Well i can tell you a little about ion-sensing tech, but dunno how Mega-Jolt is doing nowadays...

Technical details is that ion-sensing is a SAAB invention that has been around for a while. Simply put, it involves putting voltage over spark-plug gap directly after firing and measuring current leak. If mixture has detonated uncontrollably it will give different current spike, which can be detected with electronics.

As soon as detonation has been detected, ECU (at least Trionic) will try to richen that particular cylinder and wait for another power-stroke...if that doesn't work it will delay ignition in next stroke and do that again subsequently until detonation is not detected anymore, even lowering boost if it's really pervasive. It will then start to creep ignition/boost uppwards, until it reaches the limit it previously sensed detonation...leaving it at ragged edge of detonation (where engine is as most efficient). It's sort of fuzzy-logic in the engine, allowing ECU to adopt fuel/spark to whatever octane-rating you are using. ECU is also slightly biased so it can "creep upwards" if you go from bad fuel to good one.

This is done on per-cylinder basis so you can have one cylinder with more ignition delay than the others. There are also certain default maps that are used, and backup-maps that ECU falls on if knock is detected.

As you probably understand, it's quite complicated compared to ordinary fuel/ignition map so most manufacturers doesn't seem to bother with it...especially on non-turbocharged cars that don't expirience such wide range of dynamic compression and can get by using ordinary acoustic sensor (aka. piezo-microphone).

If you want to dig even deeper, i suggest reading details of patent:

http://l2.espacenet.com/espacenet/bnsviewer?CY=se&LG=se&DB=EPD&PN=US4648367&ID=US+++4648367A1+I+

[Zendalar]

Actually, there is a software to MS that will control ignition too, very minor things need to be done to the wiring.

http://home.comcast.net/~tjhafner/MegaSpark.html

[cowtown]

Thanks guys. MegaSpark looks interesting, but may be more than I want to bite off right now. I'm actually not committed to EFI yet, I'm just fascinated with the MS unit, and may not be able to keep myself from buying one.

Goran, that was a great primer on ion-sensing, which I had never heard of before.

It appears that there are at least three spark-control addons to the MS. I found a pretty good index page here for those interested:

http://not2fast.wryday.com/ignition/

Colin

[turbo6bar]

When Bruce and Al (Megasquirt creators) release UltraMegasquirt, the aftermarket companies will be shaking in their boots. As far as timeframe, I wouldn't hold my breath.

[Matt_'77_2.7]

I think you would be suprised. There is starting to be a lot of competition out there for EMS. By the time B & G have their Ultra out the gap might not be nearly so large. DTA's system with everything, but knock control is $1600. That isn't too bad compared to some others.

Matt

[cowtown]

I have not run across UltraMegaSquirt information, but the MegaSquirt'n'Spark does look interesting (got to love these Science-Fair names).

The MS'n'Spark retasks the fast-idle control line of a standard MS box, to feed your existing CDI box an ignition pulse. You keep your distributor and coil, and have PC-based spark and fuel maps. The spark software coexists with the fuel software, and it all runs on the one box. Cool.

The other approach is MegaSpark, which looks like it uses an entirely separate MS box as an ignition computer. So you would have two MS boxes installed, I guess.

It appears that the MS'n'Spark would be just as functional as a coil-on-spark solution for most uses, and a lot cheaper. I would be able to keep my brand new Crane HI6 box, which I'm pleased with so far.

No knock sensing, though.

Colin