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> MegaSquirt Question ...
SirAndy
post Nov 2 2004, 04:47 PM
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anyone here know if i can use the MegaSquirt to run just a single injector at a very high pulse, like let's say 32 times per revolution of the crankshaft ...

possible or do i need to build/program my own FI-Brain ?
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Mueller
post Nov 2 2004, 04:53 PM
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i think the limiting factor will be how long you need the injector open for each "squirt"
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SirAndy
post Nov 2 2004, 04:57 PM
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QUOTE(Mueller @ Nov 2 2004, 03:53 PM)
i think the limiting factor will be how long you need the injector open for each "squirt"

well, let's see, 32 times per revolution, it's probably going to spin up to 10k soooo, i would need 320000 squirts per minute ....

any injectors out there that can handle this ???
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Mark Henry
post Nov 2 2004, 04:59 PM
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Yep if you did trick it and you were trying to fire it 32 times per revolution of the crankshaft, on a running engine the injector couldn't keep up.
The injector still has mechanical limitations.
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SirAndy
post Nov 2 2004, 05:01 PM
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i just though about something ...

if i run 4 injectors on the same intake i could reduce the squirts per injector to 80000 per minute and get the same effect ...

like this ...


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SirAndy
post Nov 2 2004, 05:02 PM
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so, what's the max. squirts per minute for a good injector ????

anyone any ideas?
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Mueller
post Nov 2 2004, 05:03 PM
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is this for the engine design you and discussed a few years ago?? I was actually thinking about it lst week while sitting in traffic...I still don't have a decent combustion chamber idea (IMG:style_emoticons/default/headbang.gif)
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SirAndy
post Nov 2 2004, 05:04 PM
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QUOTE(Mueller @ Nov 2 2004, 04:03 PM)
is this for the engine design you and discussed a few years ago?? I was actually thinking about it lst week while sitting in traffic...I still don't have a decent combustion chamber idea (IMG:style_emoticons/default/headbang.gif)

yes. i think i might be onto something ...

i would love to get a prototype running!
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lapuwali
post Nov 2 2004, 05:28 PM
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Most injectors have a minimum cycle type (fully closed to fully open to fully closed again) in the 2-3 millisecond range. So, you're looking at 300-500/sec as a maximum. This also doesn't include the time it has to deliver the fuel, which can be lengthy at most common fuel pressures (several more milliseconds). A 10K rpm four-stroke twin (say, a racing bike) is about the worst case for these things, and that's only 40 injection events per second. Even such engines often use two injectors per cylinder just to get enough fuel in the thing in the alloted time.

Figure 50/sec is pushing the envelope, and design from there.
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SirAndy
post Nov 2 2004, 05:32 PM
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ok, so i found injectors that can be run up to 50k rpm!

that means if i run 8 injectors on the intake i could have it spin up to 10k rpm and run only 40k squirts per minute per injector!


can MegaSquirt handle 8 injectors ???
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SirAndy
post Nov 2 2004, 05:35 PM
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QUOTE(lapuwali @ Nov 2 2004, 04:28 PM)
Figure 50/sec is pushing the envelope, and design from there.

eewh, that wouldn't work. i need *MUCH* more than that ...

(IMG:style_emoticons/default/sad.gif) Andy

hmmmm, i might be able to run them at 100% (wide open all the time) to get a constant flow as i would have 32 power "strokes" per revolution ...
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Dr Evil
post Nov 2 2004, 05:47 PM
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MS handles 8 injectors at up to 10K RPM, IIRC. Why not just do a K-jet type of approach? CIS?
HTH
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Andyrew
post Nov 2 2004, 06:05 PM
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What would this be for andy?

I dont get it.... (IMG:style_emoticons/default/sad.gif)
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SirAndy
post Nov 2 2004, 06:09 PM
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i'am designing my own "rotary" engine that has absolutly nothing in common with traditional rotary engines. completely different approach.

single intake, 32 power "strokes" per revolution, high compression, high rpm (probably in the 10k range) ...

need to figure out how to feed the beast ...
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Aaron Cox
post Nov 2 2004, 06:15 PM
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crazy german! (IMG:style_emoticons/default/laugh.gif)

im intrigued!
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physician
post Nov 2 2004, 06:39 PM
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how many rotors? intake ports?

injectors work with duty cycle. and you may have problems with injecting the right quantity of fuel in the time allowed. i add the fact that in that time and speed the fuel may not atomise corectly to burn right. in bikes, they put injectors before the throttle body and sometimes, injectors shoot away from the valve( to the throttle body) so it got enough time to atomise corectly. you may consider thism don't know if it will help you

i want more info on your project, look interesting to me... it's enternaing until i finally put my gsxr 954 itb and tune them on the race civic... but that's another story here...
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JeffBowlsby
post Nov 2 2004, 06:40 PM
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It sounds like a full time duty cycle. The PW would approach zero...so why not just run an injector full time...(CIS?) and vary pressure.
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SirAndy
post Nov 2 2004, 06:44 PM
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QUOTE(physician @ Nov 2 2004, 05:39 PM)
how many rotors? intake ports?

2 rotors, but they both share the "power strokes" (don't know how else to call them, they ain't strokes, but ...), in my example each rotor get's 16 power strokes per revolution, so both rotors deliver equal power.

one intake port, one exhaust port ...

hmmmm, maybe i could just run a weber carb for the prototype ...
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lapuwali
post Nov 2 2004, 06:49 PM
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I'm in agreement. You can regulate pressure very accurately. Pulsed injection doesn't sound like a good fit with this application, unless you inject the fuel well away from the ports, and don't bother to time it (thus, providing something like continuous injection, but varying fuel flow using pulses instead of pressure).

I'd be interested to see a basic sketch of the design. If it's really not been done before, I'd salute you. Nearly everything imaginable has been tried over the past 100 years, 90% of it in the first 30 years.
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Andyrew
post Nov 2 2004, 07:12 PM
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what about running 2 or 4 megasquirt systems?

just a thought...
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