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Re: determine engine load with MAP or MAF??

Posted: Thu Feb 06, 2014 9:20 pm
by superlen
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

Re: determine engine load with MAP or MAF??

Posted: Fri Feb 07, 2014 1:08 am
by Fred
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.

Re: determine engine load with MAP or MAF??

Posted: Fri Feb 07, 2014 2:47 am
by superlen
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.

Re: determine engine load with MAP or MAF??

Posted: Fri Apr 24, 2015 6:28 pm
by Marek0086
How did you go with your tuning, Settra?... did you blow your engine up?