MegaSquirt Question ... |
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MegaSquirt Question ... |
SirAndy |
Nov 2 2004, 04:47 PM
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#1
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ? (IMG:style_emoticons/default/idea.gif) Andy |
Mueller |
Nov 2 2004, 04:53 PM
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#2
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
i think the limiting factor will be how long you need the injector open for each "squirt"
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SirAndy |
Nov 2 2004, 04:57 PM
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#3
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ??? (IMG:style_emoticons/default/idea.gif) Andy |
Mark Henry |
Nov 2 2004, 04:59 PM
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#4
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
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. |
SirAndy |
Nov 2 2004, 05:01 PM
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#5
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ... Attached image(s) |
SirAndy |
Nov 2 2004, 05:02 PM
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#6
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
so, what's the max. squirts per minute for a good injector ????
anyone any ideas? (IMG:style_emoticons/default/idea.gif) Andy |
Mueller |
Nov 2 2004, 05:03 PM
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#7
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
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 |
Nov 2 2004, 05:04 PM
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#8
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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! (IMG:style_emoticons/default/rolleyes.gif) Andy |
lapuwali |
Nov 2 2004, 05:28 PM
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#9
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
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. |
SirAndy |
Nov 2 2004, 05:32 PM
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#10
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ??? (IMG:style_emoticons/default/idea.gif) Andy |
SirAndy |
Nov 2 2004, 05:35 PM
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#11
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ... |
Dr Evil |
Nov 2 2004, 05:47 PM
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#12
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Send me your transmission! Group: Members Posts: 22,995 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region |
MS handles 8 injectors at up to 10K RPM, IIRC. Why not just do a K-jet type of approach? CIS?
HTH |
Andyrew |
Nov 2 2004, 06:05 PM
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#13
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
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SirAndy |
Nov 2 2004, 06:09 PM
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#14
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ... (IMG:style_emoticons/default/smile.gif) Andy |
Aaron Cox |
Nov 2 2004, 06:15 PM
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#15
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
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physician |
Nov 2 2004, 06:39 PM
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#16
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still looking for a teener.... Group: Members Posts: 86 Joined: 19-March 04 From: quebec Member No.: 1,819 |
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... |
JeffBowlsby |
Nov 2 2004, 06:40 PM
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#17
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914 Wiring Harnesses Group: Members Posts: 8,490 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
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 |
Nov 2 2004, 06:44 PM
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#18
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Resident German Group: Admin Posts: 41,623 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 ... (IMG:style_emoticons/default/idea.gif) Andy |
lapuwali |
Nov 2 2004, 06:49 PM
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#19
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
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. |
Andyrew |
Nov 2 2004, 07:12 PM
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#20
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
what about running 2 or 4 megasquirt systems?
just a thought... |
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