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rep_movsd
TO220 - Visibile
Joined: Sun Jan 20, 2013 4:15 pm Posts: 4
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I'm going to work on an experimental prototype engine, that will be a six-stroker - i.e. An extra stroke after the power stroke that inducts only air (later I will be injecting water) to absorb residual heat energy and convert it to some mechanical work.
Thus I need an EFI that is capable of delivering 0 fuel on certain strokes. How hard is it to customize the FreeEMS firmware to do this? I have extensive low-level software development experience for the PC (C / Assembler / Device drivers) and some micro-controller experience.
At first glance I would assume the software changes should be quite simple, but I just need to know. This is the first time I am working with an EFI system.
Thanks in advance Vivek
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Sun Jan 20, 2013 4:26 pm |
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pishta
LQFP112 - Up with the play
Joined: Wed Aug 28, 2013 6:07 am Posts: 147
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how big will the valves be to evacuate the water that is not compressable? Must be pretty big? I dont get it. Any updates? Is the air stroke always the 6th? That would be easy to decipher with a cam sensor or combo crank/cam sensor combo.
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Wed Oct 16, 2013 5:02 am |
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Fred
Moderator
Joined: Tue Jan 15, 2008 2:31 pm Posts: 15379 Location: Home sweet home!
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Thanks for bump, pishta.
To do this in a non-hacky way would be quite a challenge. To do this in a hacky way wouldn't be difficult, maybe.
The variables that deal with crank angles hold up to 720 degrees. They hold a bit more, but not 1.5x more and would overflow past that. So you need to upgrade the variable to 32 bits, which would be a pain, or change the scale of the variable, which would also be a pain. If you ever get the engine built and FreeEMS attached, post again and we'll figure something out for you.
Fred.
_________________DIYEFI.org - where Open Source means Open Source, and Free means Freedom FreeEMS.org - the open source engine management system FreeEMS dev diary and its comments thread and my turbo truck!n00bs, do NOT PM or email tech questions! Use the forum! The ever growing list of FreeEMS success stories!
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Wed Oct 16, 2013 7:35 am |
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rep_movsd
TO220 - Visibile
Joined: Sun Jan 20, 2013 4:15 pm Posts: 4
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I still need to get a donor motorbike for this.
Water injection I am not very keen on, since there are issues with creating corrosion and thermal stress.
All I would actually need is to count crank revolutions and turn off the injector on every other intake stroke, so technically not a 6 stroker, more like an 8 stroker.
Codewise I think I could manage, even if it involved lots of rewriting, what I have no clue about is how to interface with the fuel injectors and other sensors etc.
I think I will start by replacing the proprietary ECU of the bike with a FreeEMS and then once it runs reliably for a couple of Kilomiles, then start editing the code.
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Wed Oct 16, 2013 7:46 am |
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Fred
Moderator
Joined: Tue Jan 15, 2008 2:31 pm Posts: 15379 Location: Home sweet home!
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Sounds like a four stroke to me!
_________________DIYEFI.org - where Open Source means Open Source, and Free means Freedom FreeEMS.org - the open source engine management system FreeEMS dev diary and its comments thread and my turbo truck!n00bs, do NOT PM or email tech questions! Use the forum! The ever growing list of FreeEMS success stories!
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Wed Oct 16, 2013 9:09 am |
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rep_movsd
TO220 - Visibile
Joined: Sun Jan 20, 2013 4:15 pm Posts: 4
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Rather a hack on the fuel injection, for experimental purposes
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Wed Oct 16, 2013 11:40 am |
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HD13
DIP8 - Involved
Joined: Mon Apr 08, 2013 8:01 pm Posts: 24
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Try using a fourstroke lawnmower engine, cheaper and simple. I think that wil be first one for FreeEems. When that works try a motorcycle or small car engine.
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Wed Oct 16, 2013 5:13 pm |
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Fred
Moderator
Joined: Tue Jan 15, 2008 2:31 pm Posts: 15379 Location: Home sweet home!
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Motorcycles are easy or hard depending on how they're setup. Same goes for any engine type. Small stuff is challenging in some ways. The easiest engines to run are 4 cylinder or 6 cylinder japanese stuff like toyota, mazda, mitsubishi.
_________________DIYEFI.org - where Open Source means Open Source, and Free means Freedom FreeEMS.org - the open source engine management system FreeEMS dev diary and its comments thread and my turbo truck!n00bs, do NOT PM or email tech questions! Use the forum! The ever growing list of FreeEMS success stories!
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Wed Oct 16, 2013 6:10 pm |
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rep_movsd
TO220 - Visibile
Joined: Sun Jan 20, 2013 4:15 pm Posts: 4
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I will be doing it on one of the new Royal Enfield Classic EFI - Even these new ones are simple enough for a Neanderthal to work with. The factory ECU is good, but can't be reprogrammed or hacked cheaply. At most the maps can be changed.
Meanwhile I also want to retro fit EFI to my old school iron barrel Enfield.
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Wed Oct 16, 2013 6:22 pm |
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sim
LQFP112 - Up with the play
Joined: Thu Jun 02, 2011 8:17 pm Posts: 112
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pishta wrote: how big will the valves be to evacuate the water that is not compressable? Must be pretty big? I dont get it. Any updates? Is the air stroke always the 6th? That would be easy to decipher with a cam sensor or combo crank/cam sensor combo. I think the water being injected is in the form of tiny droplets. The idea is the droplets flash to steam and help to push the piston down on the sixth stroke. This works on a four-stroke also, though the main reason to inject water in that case is to cool the intake charge.
_________________ <@TekniQue> but in the end, it's code that makes a computer useful
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Fri Oct 18, 2013 1:29 am |
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