Megasquirt Megasquirt II development for rotary
01-13-06, 11:41 AM
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Megasquirt II development for rotary
i'm just wondering what the current status of MS-II working on rotary engines is?
i'd be interested in actually working on the development or testing things out. i am starting to work with MS-II for my university's Formula SAE team, so once i become familiar with it i might be able to do something for getting it to work on rotary engines.
any info or even links appreciated.
thanks
- Aaron
i'd be interested in actually working on the development or testing things out. i am starting to work with MS-II for my university's Formula SAE team, so once i become familiar with it i might be able to do something for getting it to work on rotary engines.
any info or even links appreciated.
thanks
- Aaron
01-13-06, 11:59 AM
#2
MegaSquirt Mod
once the ms2 2.55 code comes out, you could probably use it just fine with leading-only if you cut 2 teeth out of the CAS and set it up as a 12-1 wheel.
I'm going to be writing some code to make it work with a stock CAS and with trailing once B&G release the 2.55 code.
I'll probably also nuke the CAN bus code from that, and add some of the other features from msns-extra.
But if you want to run the MS2 right now, or at least soon, you'll want to use the 2.55 code that should be released real-soon-now, cut 2 opposing teeth out of your CAS, and run leading-only.
When the GPIO and router boards come out, I plan on developing sequential staged injection code, and rotary ignition code for that setup as well...
To use the stock ignitor with the ms2's ignition output, you'll need to make sure your ignition output is a +5v square-wave (I'm pretty sure you can configure this in software) and make sure that the rising edge of the square wave starts charging the coil, and the falling edge fires it.
I'm going to be writing some code to make it work with a stock CAS and with trailing once B&G release the 2.55 code.
I'll probably also nuke the CAN bus code from that, and add some of the other features from msns-extra.
But if you want to run the MS2 right now, or at least soon, you'll want to use the 2.55 code that should be released real-soon-now, cut 2 opposing teeth out of your CAS, and run leading-only.
When the GPIO and router boards come out, I plan on developing sequential staged injection code, and rotary ignition code for that setup as well...
To use the stock ignitor with the ms2's ignition output, you'll need to make sure your ignition output is a +5v square-wave (I'm pretty sure you can configure this in software) and make sure that the rising edge of the square wave starts charging the coil, and the falling edge fires it.
Last edited by muythaibxr; 01-13-06 at 12:01 PM.
01-13-06, 06:47 PM
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yeah, i should have mentioned that i want to get leading and trailing system working.
i did know that you could do leading-only with the trigger wheel modification.
good to know you are also wanting to work on it.
yeah, taking out the CAN code should free up some room. we are looking to do that for our FSAE implementation. have people already done this? taking out the code i mean.
i'm not quite sure about making it a +5v square wave. i could see some possible issues with the stock CAS. i'm not too familiar with that stuff yet.
is it not possible to use an aftermarket trigger wheel and, say, hall-effect sensor? it might take a little work but would ensure that there wouldn't be any problems with the ignition output.
i did know that you could do leading-only with the trigger wheel modification.
good to know you are also wanting to work on it.
yeah, taking out the CAN code should free up some room. we are looking to do that for our FSAE implementation. have people already done this? taking out the code i mean.
i'm not quite sure about making it a +5v square wave. i could see some possible issues with the stock CAS. i'm not too familiar with that stuff yet.
is it not possible to use an aftermarket trigger wheel and, say, hall-effect sensor? it might take a little work but would ensure that there wouldn't be any problems with the ignition output.
01-13-06, 10:19 PM
#4
MegaSquirt Mod
there won't be any problems with it even with the CAS.
Getting the trigger wheel even with modification to work is not yet possible, it won't be until 2.55 is released.
The stock CAS shouldn't be a problem... with the v3 board's built-in VR sensor conditioner, and the lm1815 second trigger circuit, turning the VR sensor output into a +5v square wave is no problem. There's just not any code in the ms2 yet for the second trigger, and I'll be adding that when 2.55 comes out.
The +5v square wave that I was talking about is the spark output to the ignitors. That also shouldn't be a problem, I just found that you can jumper JS10 to IGN to get a +5v square wave out of the processor. The only remaining problems are the split table and the actual trailing outputs themselves.
Anyway, I'm definitely going to write the code to do what needs to be done here, and probably some code for up to v8 wasted spark or 4 cylinder COP, and add some other features.. It's just a matter of when. I also might rewrite whatever B&G come up with for a wheel decoder if their implementation doesn't make use of all the teeth on the wheel. I'll probably start on this after I'm done rewriting the msns-extra wheel-decoder to make use of all the teeth on the wheel.
Ken
Getting the trigger wheel even with modification to work is not yet possible, it won't be until 2.55 is released.
The stock CAS shouldn't be a problem... with the v3 board's built-in VR sensor conditioner, and the lm1815 second trigger circuit, turning the VR sensor output into a +5v square wave is no problem. There's just not any code in the ms2 yet for the second trigger, and I'll be adding that when 2.55 comes out.
The +5v square wave that I was talking about is the spark output to the ignitors. That also shouldn't be a problem, I just found that you can jumper JS10 to IGN to get a +5v square wave out of the processor. The only remaining problems are the split table and the actual trailing outputs themselves.
Anyway, I'm definitely going to write the code to do what needs to be done here, and probably some code for up to v8 wasted spark or 4 cylinder COP, and add some other features.. It's just a matter of when. I also might rewrite whatever B&G come up with for a wheel decoder if their implementation doesn't make use of all the teeth on the wheel. I'll probably start on this after I'm done rewriting the msns-extra wheel-decoder to make use of all the teeth on the wheel.
Ken
01-13-06, 11:36 PM
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Ok Ken, thanks for that information. Keep us up to date on how it goes. 
and once i get a little more familiar with MS programming i might try to look into some of the stuff myself.
i know a decent amount of programming and microcontroller implementation, i just haven't done anything on MS before. i'd love to learn.
and once i get a little more familiar with MS programming i might try to look into some of the stuff myself.
i know a decent amount of programming and microcontroller implementation, i just haven't done anything on MS before. i'd love to learn.
01-14-06, 01:18 AM
#6
Lives on the Forum
It's always nice to have hard working people do these things for the good of the enthusiast. Thanks.
One of these days I may get a megasquirt to run my car, probably after I graduate, and it's nice to know that they'll be some useful knowledge about running the 13B with it out there.
One of these days I may get a megasquirt to run my car, probably after I graduate, and it's nice to know that they'll be some useful knowledge about running the 13B with it out there.
02-03-06, 03:14 AM
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I'm about to join the development too hehe
I've just ordered a MS II kit which I will soon be building and hooking up to my 1982 RX7, with S4 13B N/A here in Australia. Will be doing a lot of dynotime with it and tuning for optimal settings of course. I was thinking i should start off with fuel only, once that it working as well as possible then look into running spark off it as well
I've just ordered a MS II kit which I will soon be building and hooking up to my 1982 RX7, with S4 13B N/A here in Australia. Will be doing a lot of dynotime with it and tuning for optimal settings of course. I was thinking i should start off with fuel only, once that it working as well as possible then look into running spark off it as well
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04-04-06, 03:03 AM
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any updates on this?
in any case, i think i'm going to pick up a MS-II kit within the next two months or so, then just slowly have it good to go for install. in the mean time hopefully we can get some progress going to have full operation on the rotary.
i've become a lot more familiar now with the MS code (especially the MS-II C code), since we are planning on using it for my university's FSAE car.
if it is of any interest, we have also figured out how to get rid of idle air control circuit and a few other things to give 2 injection channels and 2 ignition channels, and are also looking to see how to get 4 channels for either one of them. in addition to this we will also be modifying hardware/software to support using TWO ignition sensors at the same time, a hall effect and VR sensors.
anyways, i don't mind using my car as the test bed for MS-II as long as nothing goes horribly wrong, heh.
in any case, i think i'm going to pick up a MS-II kit within the next two months or so, then just slowly have it good to go for install. in the mean time hopefully we can get some progress going to have full operation on the rotary.
i've become a lot more familiar now with the MS code (especially the MS-II C code), since we are planning on using it for my university's FSAE car.
if it is of any interest, we have also figured out how to get rid of idle air control circuit and a few other things to give 2 injection channels and 2 ignition channels, and are also looking to see how to get 4 channels for either one of them. in addition to this we will also be modifying hardware/software to support using TWO ignition sensors at the same time, a hall effect and VR sensors.
anyways, i don't mind using my car as the test bed for MS-II as long as nothing goes horribly wrong, heh.
Last edited by coldfire; 04-04-06 at 03:09 AM.
04-04-06, 07:42 AM
#9
MegaSquirt Mod
most likely, jsmcortina and I will have a version of "MS2/Extra" coming out over the next few months.
I've started working on making the ISR_Ign_TimerIn() routine faster (right now it takes an average of 166 usec to execute with 2nd derivatives turned on). As soon as I'm done with that, I'm going to fix up the beta wheel decoder.
Once Al officially calls his code "done," James and I intend to add as many of the features from msns-extra as we can. We'll be using the LED's for ignition, pin #10 as a second trigger input, etc... We're also going to write a wheel decoder that uses every tooth on whatever wheel you're using to tell engine position, making a lot of the derivative code unnecessary.
Finally, we're trying to get ALL of the interrupt handlers together, aside from the two ignition related ones down to 10 usec. At that level, the jitter on the ignition channel will be 10 usec or less. At 8000 rpms, that'll give us spark accuracy of .5 degrees.
We're going to be doing this work over the next several months, so if you want to do your own thing, go for it. It's going to take us a while to get something we're happy with. (So basically don't wait for us. If you want something working *now* get the ms1 and run msns-extra on it. You ca nalways upgrade later).
I've started working on making the ISR_Ign_TimerIn() routine faster (right now it takes an average of 166 usec to execute with 2nd derivatives turned on). As soon as I'm done with that, I'm going to fix up the beta wheel decoder.
Once Al officially calls his code "done," James and I intend to add as many of the features from msns-extra as we can. We'll be using the LED's for ignition, pin #10 as a second trigger input, etc... We're also going to write a wheel decoder that uses every tooth on whatever wheel you're using to tell engine position, making a lot of the derivative code unnecessary.
Finally, we're trying to get ALL of the interrupt handlers together, aside from the two ignition related ones down to 10 usec. At that level, the jitter on the ignition channel will be 10 usec or less. At 8000 rpms, that'll give us spark accuracy of .5 degrees.
We're going to be doing this work over the next several months, so if you want to do your own thing, go for it. It's going to take us a while to get something we're happy with. (So basically don't wait for us. If you want something working *now* get the ms1 and run msns-extra on it. You ca nalways upgrade later).
04-04-06, 11:10 AM
#11
MegaSquirt Mod
the ignition itself shouldn't be more than a degree... the dwell is probably more, but dwell is set in ms and doesn't change the ignition timing.
On the scope, at 8000 rpms, I can see up to a .2ms (200 usec) jitter in the dwell because the dwell at those revs is done from the .1 ms section (executes every 100 usec), but I've never seen any jitter at all on the spark side until about 12000 rpms, but I've never tried looking at it with microsecond resolution on my scope. Assuming 20-30 usec, which is possible, the error would be as below:
At 20 usec, you get about .96 degrees accuracy at 8000 rpms, so it's accurate to about 1 degree. At 30 usec, you get 1.44 degrees accuracy. So assuming you stay between 20 and 30 microseconds MAX you'll get a maximum error of .96-1.44 degrees.
Keep in mind that as revs drop, 20-30 usec of jitter causes less error. At 3000 rpms for example, 20 usec is .36 degrees, and 30 usec is .54 degrees.
Last, as I said, I've never seen any jitter on the spark side of the square wave at anything below around 12000 rpms, so it's likely that the error is less than what I've calculated above....
Since I have to gear up to test this sort of thing on the MS2 anyway, maybe I'll go back and do a little measurement on the ms1 with msns-extra to see what it's like there for sure.
Ken
On the scope, at 8000 rpms, I can see up to a .2ms (200 usec) jitter in the dwell because the dwell at those revs is done from the .1 ms section (executes every 100 usec), but I've never seen any jitter at all on the spark side until about 12000 rpms, but I've never tried looking at it with microsecond resolution on my scope. Assuming 20-30 usec, which is possible, the error would be as below:
At 20 usec, you get about .96 degrees accuracy at 8000 rpms, so it's accurate to about 1 degree. At 30 usec, you get 1.44 degrees accuracy. So assuming you stay between 20 and 30 microseconds MAX you'll get a maximum error of .96-1.44 degrees.
Keep in mind that as revs drop, 20-30 usec of jitter causes less error. At 3000 rpms for example, 20 usec is .36 degrees, and 30 usec is .54 degrees.
Last, as I said, I've never seen any jitter on the spark side of the square wave at anything below around 12000 rpms, so it's likely that the error is less than what I've calculated above....
Since I have to gear up to test this sort of thing on the MS2 anyway, maybe I'll go back and do a little measurement on the ms1 with msns-extra to see what it's like there for sure.
Ken
Last edited by muythaibxr; 04-04-06 at 11:15 AM.
04-05-06, 02:18 AM
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thanks for the update Ken. it looks like you guys are doing a lot of work, and are much better at this whole thing than me
so i might still want to play around with it, but i might just wait for an official release from you guys.
thanks,
Aaron
so i might still want to play around with it, but i might just wait for an official release from you guys.
thanks,
Aaron
08-28-06, 08:44 AM
#16
MegaSquirt Mod
I'm going to be starting on the rotary ignition and staged injection code this week. I also will add 2nd trigger code.
I got the MS2 wheel decoder working in a car on Saturday... It ran the ae86 with a Silver-top 20v 4age. It ran extremely well actually.
So anyway, ms2/extra will have rotary code within the next 2 weeks or so... maybe a little longer as it depends on how much time I have to work on it, and there are several bug-fixes to the ms2/extra code that I need to put in before doing the rotary work.
Ken
I got the MS2 wheel decoder working in a car on Saturday... It ran the ae86 with a Silver-top 20v 4age. It ran extremely well actually.
So anyway, ms2/extra will have rotary code within the next 2 weeks or so... maybe a little longer as it depends on how much time I have to work on it, and there are several bug-fixes to the ms2/extra code that I need to put in before doing the rotary work.
Ken
08-28-06, 01:27 PM
#18
MegaSquirt Mod
same things it gives everything else:
1) fuel calcs at 1 rpm intervals instead of 100 rpm intervals
2) pulse-widths are usec resolution instead of .1 ms (hires msns-extra does this as well)
3) X-tau accel enrichments: A more advanced way of tuning accel... so far people have gotten much better throttle response and much more controlled AFRs with this in transient conditions.
4) Smith-PID predictor algorithm for closed loop fuel control: You enter a couple of delays, and the MS predicts how much fuel to add/subtract based on current operating conditions. Leads to a very flat AFR in closed-loop operation instead of the oscillations that happen with msns-extra's current algorithm
5) Ignition timing gets more accurate with more teeth on the wheel during transient conditions: If the engine is speeding up or slowing down, msns-extra does predictions to try to determine when to fire the spark/start dwell... ms2/extra uses the extra teeth on the wheel to allow better accuracy with less complicated predictions. The more teeth the more accurate.
There are several other enhancements as well... but these are the major ones.
1) fuel calcs at 1 rpm intervals instead of 100 rpm intervals
2) pulse-widths are usec resolution instead of .1 ms (hires msns-extra does this as well)
3) X-tau accel enrichments: A more advanced way of tuning accel... so far people have gotten much better throttle response and much more controlled AFRs with this in transient conditions.
4) Smith-PID predictor algorithm for closed loop fuel control: You enter a couple of delays, and the MS predicts how much fuel to add/subtract based on current operating conditions. Leads to a very flat AFR in closed-loop operation instead of the oscillations that happen with msns-extra's current algorithm
5) Ignition timing gets more accurate with more teeth on the wheel during transient conditions: If the engine is speeding up or slowing down, msns-extra does predictions to try to determine when to fire the spark/start dwell... ms2/extra uses the extra teeth on the wheel to allow better accuracy with less complicated predictions. The more teeth the more accurate.
There are several other enhancements as well... but these are the major ones.
08-28-06, 02:43 PM
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wow, that is good work Ken.
just a question, i have a whole MS-1 kit with V3 board, what do i need to do to get MS-2? i am about to assemble it. should i just hold off and get whatever is needed for MS2?
just a question, i have a whole MS-1 kit with V3 board, what do i need to do to get MS-2? i am about to assemble it. should i just hold off and get whatever is needed for MS2?
08-28-06, 05:10 PM
#20
MegaSquirt Mod
don't wait on ms2... it's going to be about a month or more before we do an official public release. There's still a lot of work to do.
You'll end up needing all the same stuff pretty much... just some of the mods will be different.
You'll end up needing all the same stuff pretty much... just some of the mods will be different.
09-01-06, 03:30 PM
#22
MegaSquirt Mod
trailing ignition, staged injection, second trigger... all of these need to be in place to run the rotary.
Those things are intermediate on my list of things to do however. Probably within the next couple weeks, although I can't guaruntee when I'll get it done.
Those things are intermediate on my list of things to do however. Probably within the next couple weeks, although I can't guaruntee when I'll get it done.