For discussion of anything related to the Speeduino documentation wiki
By LAV1000
#46298
To me it seems like there is some differences between the Speeduino wiki and Tuner studio.

Speeduino Wiki:
Wasted COP - This is a convenience mode that uses the same timing as the 'Wasted Spark' option, however each pulse is sent to 2 ignition outputs rather than one. These are paired IGN1/IGN3 and IGN2/IGN4 (ie When IGN1 is high, IGN3 will also be high). As this is still a wasted spark timing mode, only crank position is required and there will be 1 pulse per pair, per crank revolution. This mode can be useful in cases where there are 4 individual coils, but running full sequential is either not desired or not possible (Eg when no cam reference is available).

Tuner Studio:
Wasted COP: Ignition pulses are output on all ignition channels up to the number of cylinders. Eg 4 cylinder outputs on all ignition channels. Note that your board needs to have same number of igntion outputs as cylinders to be able to run this

As I understand it, Tuner Studio uses 4 ignition outputs and each output fires once every 360 crank rotation.
Speeduino uses only 2 ignition outputs.
Both on a 4 cilinder engine.
On a 4 cilinder it doesn't matter that much.
But then on a 3 cilinder (3x120) you need to go sequential ?
By LPG2CV
#46303
@jonbill
@lav1000 and I have both come across users recently that have odd # cylinders
Myself, I would anticipate that wasted cop would fire every rev and not have to be paired with another cylinder.
2nd user has 3 cyl 2 stroke with 3 coils. But it can't be set up.
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By jonbill
#46304
LPG2CV wrote: Mon Nov 09, 2020 8:20 am @jonbill
@lav1000 and I have both come across users recently that have odd # cylinders
Myself, I would anticipate that wasted cop would fire every rev and not have to be paired with another cylinder.
2nd user has 3 cyl 2 stroke with 3 coils. But it can't be set up.
yes, I think you're right and I'm wrong :) at least with a 4 stroke, wasted spark doesn't have to mean paired cylinders.
But for a 2 stroke, there can't be any wasted sparks.
I would imagine that the engine constants setting for 2 stroke would mean that you can select sequential for fuel and spark on 3 cylinders and not need a cam signal. but what do I know?
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By pazi88
#46305
LAV1000 wrote: Mon Nov 09, 2020 5:50 am To me it seems like there is some differences between the Speeduino wiki and Tuner studio.

Speeduino Wiki:
Wasted COP - This is a convenience mode that uses the same timing as the 'Wasted Spark' option, however each pulse is sent to 2 ignition outputs rather than one. These are paired IGN1/IGN3 and IGN2/IGN4 (ie When IGN1 is high, IGN3 will also be high). As this is still a wasted spark timing mode, only crank position is required and there will be 1 pulse per pair, per crank revolution. This mode can be useful in cases where there are 4 individual coils, but running full sequential is either not desired or not possible (Eg when no cam reference is available).

Tuner Studio:
Wasted COP: Ignition pulses are output on all ignition channels up to the number of cylinders. Eg 4 cylinder outputs on all ignition channels. Note that your board needs to have same number of igntion outputs as cylinders to be able to run this
Not really. Well the text and what it says is different, but both say that wasted cop on 4cyl uses, 4 ignition outputs. Not 2 that is used in wasted spark.
By kettlekev
#46309
I think I came to the same conclusion.

On a two stroke (in my case 3 cylinders), if i understand sequential correctly (2 sparks one after the other?) then my only option would appear to be COP but my sequence is 1 then 2 then 3 at a fixed 120 degree separation and COP seems to pair two channels together so I loose the 3rd channel I need.
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By PSIG
#46317
This seems confusing. For a moment, I would forget anything "wasted". Speeduino always fires IGN channels "sequentially" IGN1-IGN2-IGN3-IGN4 (or only the number of cylinders you've entered in Settings). 2-stroke or 4-stroke per-cycle. Timing is either from the crank and beginning randomly on either 360° rotation of the 720° 4-stroke cycle; or on a specific rotation if it has cycle reference ("cam" signal); or on every rotation if 2-stroke.

If selected 4-stroke, the sequence begins at the proper moment, but random to which crank rotation, unless the cycle signal is present. However, it also begins at every crank rotation if 2-stroke is selected, and completes the sequence in one crank rotation. Note there is no wasted-anything yet.

Working backwards, this gives a 3-cylinder 2-stroke per-cycle "sequential" firing at 0°-120°-240°, all based on the crank wheel and trigger angle for timing, with no cycle signal, as it all happens in one rotation.* (Don't read the footnote until you're done, in order to reduce trivial confusion.)

For a 4-stroke, we fire the coils at 0°-240°-480° and need the cycle sensor to be sure we are on the correct crank rotation -or- (here comes the waste) fire waste-spark every 120°. This makes a spark on each cylinder, every rotation, every 360° (0°-120°-240°-360°-480°-600°). This is wasted-per-cylinder and does not involve other cylinders. One coil fires one cylinder, twice per 4-stroke cycle.

As you are considering 2-troke per-cycle, that last bit may be ignored, but is there to complete the concept. A 2-stroke only needs a crank wheel and 3 coils on the 3 cylinders, wired to the correct cylinder order, to fire "sequentially" without cycle signal.

Whatever the documentation says or its interpretation, this is how it should work. Does that help?

David

*Note - a cycle signal may be used if the crank wheel has no "missing teeth", but the timing is entirely on the crank wheel. Likewise, a cam signal with two missing teeth (emulating a missing-tooth crank signal) may be used to the same effect. Don't dwell on this. ;)
By kettlekev
#46327
David,

I believe it does. Thank you very much.

So straight forward sequential as in;
spark2.PNG
spark2.PNG (27.87 KiB) Viewed 9517 times
spark3.PNG
spark3.PNG (34.15 KiB) Viewed 9515 times
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By PSIG
#46350
The prime difference here is that selecting 2-stroke or 4-stroke tells Speeduino to stuff all of its injections and sparks into either 360° or 720°. This is a non-issue for even-fire 2-stroke (all events in one crank rev), but on 4-stroke we need to either provide a cycle signal (single sparks) or set to wasted in order to hit each cylinder with sparks at the right time.

Same goes for non-sequential fuel, where 2-stroke all sequence in one crank rotation (unavoidably sequential), and on 4S we can either allow random fuel injection and port fuel dwelling, or we can fire injections 2-squirts per-cylinder, per-cycle (equivalent to waste-spark) in order to allow consistent sequenced injection timing for every cylinder with repeatable port fuel dwell. Also known as double-shot sequential or other similar terms; 2-squirt-injection creates a similar true sequential environment with timed injections on both rotations, carrying any benefits that consistency and system response brings.

These topics created quite a flurry of dialogue in the past, where the various functions did not perform as-intended (e.g., 4S-Alternating). I have not tested these functions in all of these modes, so take the theory for what it is, but test your setup on the bench before assuming everything is as-intended. That reminds me, that there are still a number of functions that do not work "as-intended", so verify everything. ;)

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