3 cylinder simultaneous fuel injection

For discussing injector selection, manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
djaksha
MegaSquirt Newbie
Posts: 3
Joined: Sat Jul 30, 2016 6:40 pm

3 cylinder simultaneous fuel injection

Post by djaksha »

I could not find the answer to this, so maybe someone can explain it for me.

I have an application using a 3 cylinder engine, each cylinder fitted with a throttle body. If I under stand the microsquirt installation,
I can only run the engine using simultaneous injection. I believe that this means that all three throttle bodies will fire during each cylinders intake stroke.
What happens to the extra fuel that is injected into the manifold that is not directly opposite the cylinder in its intake phase.

Is it all swept into the single cylinders intake stroke?
Is some ~ 2/3 of the injected fuel wasted?
Does each injector only squirt 1/3 of necessary fuel, so the the cylinder on its intake stroke scavenges 1/3+1/3+1/3 from each throttle body?

Clarification please.

Thanks,

Dave
Matt Cramer
Super Squirter
Posts: 910
Joined: Sat Jul 03, 2004 11:35 am

Re: 3 cylinder simultaneous fuel injection

Post by Matt Cramer »

It's generally swept in on the intake stroke. Unless that intake manifold is very short, you won't have much of it be able to get out of the runner before the valve opens and pulls it in.
Matt Cramer at DIY Autotune
Image
djaksha
MegaSquirt Newbie
Posts: 3
Joined: Sat Jul 30, 2016 6:40 pm

Re: 3 cylinder simultaneous fuel injection

Post by djaksha »

Thanks, Matt.

Does that mean, then, that each injector supplies 1/3 of the total fuel charge for the cylinder on the intake stroke?

IF so, how do you set up the software to do this?

Thanks,

Dave
dontz125
Master Squirter
Posts: 375
Joined: Mon Jun 29, 2009 1:00 pm
Contact:

Re: 3 cylinder simultaneous fuel injection

Post by dontz125 »

You have 3 injectors feeding 3 cylinders, each injecting 3 times per engine cycle. Just input the numbers as though each injector was dedicated to its cyl, and the math works out.
djaksha
MegaSquirt Newbie
Posts: 3
Joined: Sat Jul 30, 2016 6:40 pm

Re: 3 cylinder simultaneous fuel injection

Post by djaksha »

Ok, I will try this. Thanks for the info.

Dave
Post Reply