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3 cylinder simultaneous fuel injection

Posted: Mon Aug 22, 2016 9:06 am
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

Re: 3 cylinder simultaneous fuel injection

Posted: Wed Aug 24, 2016 6:30 am
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.

Re: 3 cylinder simultaneous fuel injection

Posted: Wed Aug 24, 2016 6:42 am
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

Re: 3 cylinder simultaneous fuel injection

Posted: Wed Aug 24, 2016 2:07 pm
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.

Re: 3 cylinder simultaneous fuel injection

Posted: Wed Aug 24, 2016 8:08 pm
by djaksha
Ok, I will try this. Thanks for the info.

Dave