View unanswered posts | View active topics It is currently Sun Aug 20, 2017 1:10 am



Reply to topic  [ 24 posts ]  Go to page Previous  1, 2, 3
determine engine load with MAP or MAF?? 
Author Message
DIP8 - Involved

Joined: Tue Aug 20, 2013 9:52 pm
Posts: 25
saw some more questions I didn't answer..

Not sure of what the "timing window" is you ask about, but as covered elsewhere for batch fired, it pretty much doesn't matter when you squirt the fuel, just be consistent.

For IAT sensor curves, if you look you can find them for a lot of stock sensors. Even factory service manuals for your car will have a few data points that will get you close. Wost case, a multimeter, thermometer, & a glass of ice water will give this to you as well. Stick it in ice water, write down temp/reading, let the water warm up & keep taking readings until it reaches room temp. Repeat with hot water as it cools. Stick the numbers in a spreadsheet.

Lenny


Thu Feb 06, 2014 9:20 pm
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 14709
Location: Home sweet home!
superlen wrote:
Note: I think many programmers actually use PV=nRT to pre-calculate what the FCPW (full cylinder pulse width) would be at what's called STP. (Standard Temperature and Pressure, 100kPa & 25C) & then shrink from that based on run time readings. This is to save the math overhead done during realtime operation. I just do the math as I have plenty of processing cycles.

I'm not sure what Fred does, but MS I *think* does this as I see people talking about "base pulse" or something similar and that sounds like a pre-calculated pulse to me.

I just do the math, too, except for static components of it. I do have a base pulse width, but this is before things that intentionally alter lambda or are there to ensure lambda remains what is desired. IE, warm up and tip in and cylinder trim, etc. I find the "pre-calc everything" way very hacky... and yes, this is exactly what MegaSquirt does. They have no injector config, only a "ReqFuel" which is a dirty word meaning "base pulsewidth at STP" or similar.

Fred.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Fri Feb 07, 2014 1:08 am
Profile WWW
DIP8 - Involved

Joined: Tue Aug 20, 2013 9:52 pm
Posts: 25
Fred wrote:
I just do the math, too, except for static components of it. I do have a base pulse width, but this is before things that intentionally alter lambda or are there to ensure lambda remains what is desired. IE, warm up and tip in and cylinder trim, etc. I find the "pre-calc everything" way very hacky... and yes, this is exactly what MegaSquirt does. They have no injector config, only a "ReqFuel" which is a dirty word meaning "base pulsewidth at STP" or similar.

Fred.


Good to know that you do the calc as well. I understand why back in the day of 8bit micros the pre-calc thing was handy, but not now with cheap available processing power.


Fri Feb 07, 2014 2:47 am
Profile
DIP8 - Involved

Joined: Fri Apr 24, 2015 5:26 pm
Posts: 16
How did you go with your tuning, Settra?... did you blow your engine up?


Fri Apr 24, 2015 6:28 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 24 posts ]  Go to page Previous  1, 2, 3

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF. ColorizeIt.