ECMlink What is LOAD FACTOR...how is it calculated?

[kmetiuk]

I am interested in what load factor actually is mathematically in DSMLink.

I have created a Holset HE351VE controller that reads RPM, MAP, and TPS and can control the vanes via tables for any or all 3 sensor inputs.

I would like to create the tables so that one axis is load factor and the other RPM so that it aligns with DSMLink. I then will send an output from my controller to Link so that I can log the vane position in Link and start tuning my vane position maps. Using load factor will clearly make this easier to jump back and forth between the log and my controller.

First I need to figure out what load factor is exactly. Is it just a modified MAP value?

I have searched and searched to no avail.

 

[DogWhistle]

From ECMTuning.com:

See 2nd paragraph.

https://www.ecmtuning.com/wiki/howfueltableajustmentsareapplied

 

[kmetiuk]

From ECMTuning.com:

See 2nd paragraph.

https://www.ecmtuning.com/wiki/howfueltableajustmentsareapplied

From the 2nd para: "In V3, you get no adjustment at all below a LoadFactor of 0.8 (roughly atmospheric pressure) and you get full adjustment above 1.6 (roughly 11psi)"

This is a step in the right direction...but it says "roughly". I can look past that for now so say:
0.8 = 14.7 PSIA which yields 18.375 PSIA/ 1 Loadfactor
so then using that conversion 11 PSIG = 25.7 PSIA = 1.40 Load factor which is not what that paragraph says...it says it should be 1.6

So from that para we get 2 conversion factors:
18.40 PSIA / 1 Load factor (from the 0.8 = atmospheric (roughly))
16.06 PSIA / 1 Load factor (from the 1.6 = 11 psi (roughly))


Is there some other variable in this equation? Like volumetric efficiency or some kind of correction value?

 

[DogWhistle]

I'm on the road until Monday. Maybe someone else will step in. Otherwise, I will help you on Monday.

 

[kmetiuk]

@DogWhistle cool man. I can wait till monday....I'm juuuust finishing up installing the HE351VE. It's massive and took a bit of creative fab work to get it in.

 

[miliman13]

I Hope this helps:

http://mechanics.stackexchange.com/questions/17537/how-is-engine-load-determined

 

[kmetiuk]

Ah...there it is.

Load Factor in DSMLink is Absolute Load in the world of SAE. Thank you @miliman13.

The equation is as follows:

LOAD_ABS = [air mass (g / intake stroke)] / [1.184 (g / intake stroke) *
cylinder displacement in liters]

Derivation:

- air mass (g / intake stroke) = [total engine air mass (g/sec)] / [rpm (revs/min)* (1 min / 60 sec) * (1/2 # of cylinders (strokes / rev)]

- LOAD_ABS = [air mass (g)/intake stroke] / [maximum air mass (g)/intake stroke at WOT@STP at 100% volumetric efficiency] *100%.

Where:

- STP = Standard Temperature and Pressure = 25 °C, 29.92 in Hg (101.3 kPa) BARO
- WOT = wide open throttle

The quantity (maximum air mass (g)/intake stroke at WOT@STP at 100% volumetric efficiency) is a constant for a given cylinder swept volume. The constant is 1.184 (g/liter 3) * cylinder displacement (liter 3/intake stroke) based on air density at STP.

Characteristics of LOAD_ABS are:

- Ranges from 0 to approximately 0.95 for naturally aspirated engines, 0 – 4 for boosted engines
- Linearly correlated with engine indicated and brake torque,
- Often used to schedule spark and EGR rates,
- Peak value of LOAD_ABS correlates with volumetric efficiency at WOT.
- Indicates the pumping efficiency of the engine for diagnostic purposes.