Help with SOI and Duration

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Re: Help with SOI and Duration

Postby jurebv » Sat Mar 10, 2018 6:16 pm

Well reading this first few posts i see that program is using this exact formula , Mothahdi are your sure your were using same values you posted?

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Re: Help with SOI and Duration

Postby MothaHDI » Sat Mar 10, 2018 7:59 pm

jurebv wrote:Well reading this first few posts i see that program is using this exact formula , Mothahdi are your sure your were using same values you posted?


Your formula doesn't include rail pressure :crazy:
And yes! I am pretty sure, the data was right, but i will try again

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Re: Help with SOI and Duration

Postby jurebv » Sat Mar 10, 2018 8:22 pm

microseconds from duration map are already determined by rail pressure, if it was different rail pressure microseconds would be different

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Re: Help with SOI and Duration

Postby jurebv » Sun Mar 11, 2018 11:25 am

I quote author of EOI builder from same topic :

Alex.T wrote:What I do is convert Injection Duration from microseconds to degrees, then add that to SOI.
Resulting EOI map will have degrees ATDC.

I start from SOI and i suppose I'm at 1250rpm and I want to inject 70mm3.
SOI map will tell me I have to start injecting at 3,6° BTDC.
Now I need to know injection duration, but in order to get that, I first have to know rail pressure.
So I open Rail Pressure map and look for IQ=70mm3 and RPM=1250. This will give me 700bar.
Now I can open Injection Duration and look for IQ=70mm3 and Pressure=700bar.
Duration for that will be 1668 µs.

All I have to do now is to convert that to crankshaft degrees.
But to go from time to angles, we need to know how much time a revolution will take at given rpm.
In this case we have 1250rpm. That means every 60 seconds 1250 revolutions.
Calculate (60/1250)=0,048
That means a revolution will take 0,048 seconds.
In microseconds will be 48000.

Now, if 48000µs is the time equivalent of 360° of rotation
1168µs would be 8,76°

Add this to SOI and you'll find EOI is 5,16° ATDC.

I prefer to use BTDC for SOI and ATDC for EOI...


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Re: Help with SOI and Duration

Postby MothaHDI » Sun Mar 11, 2018 6:35 pm

Ok thx :D

So,

What i'm going to do for my stage 2:

SOI: I' gonna rent a dyno for testing, Rescale SOI for 80mm3 and try diferent values.
Questions: How do i know the limits of SOI? I need to change the SOI to match the end of injection right? So, for example is 30degrees of SOI to much?

EOI: For example, Stock EOI goes from -10 to +10!
Questions: When tunning for a diferent IQ (80mm3) what kind of EOI values should calculate for? Should i calculate to 0?

Duration: If i keep my Rail pressure below 1400bar, should i change my duration? If yes, how?
If i want to increase my rail pressurae, how do i calculate?

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Re: Help with SOI and Duration

Postby jurebv » Sun Mar 11, 2018 8:53 pm

I wouldnt mess too much with SOI, closer to TDC more pressure in cylinder. Stay atleast within OEM eoi, not before.

In rail pressure map you select which rail pressure is used at which rpm and iq, and then when you go to Duration map and check how much microseconds it takes to inject at that rail pressure and iq.

So first go to rail pressure map and set rail pressure that you want(higher) where you want, then go to duration map add new rail pressure to axis (if not already there) and extrapolate values

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Re: Help with SOI and Duration

Postby MothaHDI » Mon Mar 12, 2018 5:08 pm

jurebv wrote:I wouldnt mess too much with SOI, closer to TDC more pressure in cylinder. Stay atleast within OEM eoi, not before


Thx! Nice answer! But what do you mean with OEM EOI? Like i said the values change from -10 to +10 and i need to "add" a new axis. I'm confused :?


jurebv wrote:then go to duration map add new rail pressure to axis (if not already there) and extrapolate values


What do you mean with extrapolate? copy? make a direct relation with the last values? I dont know the meaning of the expression :(

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Re: Help with SOI and Duration

Postby jtdpow » Mon Mar 12, 2018 6:03 pm

for extrapolate i use linear interpolation calculator,not perfect,but do the job well

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Re: Help with SOI and Duration

Postby uberderv » Mon Mar 12, 2018 7:16 pm

Just wanted to make sure you know about the SOI limiter- edc15c2-soi-limiter-t17082

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Re: Help with SOI and Duration

Postby MothaHDI » Mon Mar 12, 2018 7:57 pm

uberderv wrote:Just wanted to make sure you know about the SOI limiter- edc15c2-soi-limiter-t17082


wow, thx :)

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