very useful info. thanks!
what about axis values? what does the ecu do when it's in the middle of two axis' values?
I described two ways of working in my prevoius post with torque limiter example.
which way is it?

I have a VERY good example for you also good answer for your previous
question:

(if you look at the x axis you will see how clumsy the original map is
- look at the jumps: 100 200 200 200 100 100 200
- here you really have to think what you will do. Is it linear - NO
- what will you do --> the advantage is tuner experience)

I wont be talking about methodology of calculating the
precontrol value right now, maybe at some other topic because
it take some more time and it is a complicated map with bunch of
other connected problems.

Lets imagine you are working on your extreme tune and you are facing
a problem with rail pressure deviation at 2500rpm and 1200bar
at full throttle from 2200+ in 5th gear.

Your car starts struggling. The original map looks like
attached and you want to know how much % the valve is closed
at that RPM and pressure in comparison with your diag measurement.
Lets say your diag shows 43, you want to be sure how ECU calculates,
now you check the map what the map has to say...

AXIS X: 1100-->1300
AXIS Y: 2000rpm-->3000rom


It is: (40.5 + 47.36 + 39 + 45) / 4 = 42.96 (look at the picture)

You can see that ECU calculates like that because you measured 43..

Lets imagine you increased IQ, Rail pressure, ID and so on,
and you recalculate you need more closed valve...

For example, lets say you calculated you need 46%,
now you know WHAT you have to do, to get there and WHERE.

Hope you understand.

So it's using interpolation both in x and y ways.
Interesting.
What happens when it gets off the axis limit?
Suppose you're getting to 1400 bar rail pressure, but the map doesn't cover that.
Is it going to use tha last known value?
(1300bar in this case)

In this case it goes over till your Rail limiters.

ecuedit wrote:In this case it goes over till your Rail limiters.

I'm not talking about how high rail pressure gets.
I use it as an example. I'm only asking what happens when you are in a situation where an axis is not defined?
I took 1400bar as an example because it's not in the axis. I know it will get limited by SVRPLs. But suppose for one moment the ECU has only the map you attached. Nothing else. What will the ecu do if it gets 1400bar and 3000rpm?
Will it keep 45.00?
Or maybe it uses extrapolation to calculate a value like 49.00?

If you are not blocked by the rail pressure limiters then the ecu will use the last value from the known map. In this case(looking at the attached picture) that will be 45% at 3000 RPM.

To sum up,
With values inside a map, the ECU uses interpolation.
Outside the map, it uses last known value.

But if it does interpolation, it's not jumping through values.
Then why do you talk about jumps?

Hi guys, sorry to butt in, but please can someone tell me what IQ is ...? And the other acronyms?
It's difficult to learn something whe you don't k wo what you are reading.


I looked form the descriptions in dictionary, but IQ is not there? Maybe update the dictionary will help alot of us noobs.

Just a suggestion.

Nice suggestion:

acronyms-t141

Alex.T wrote:To sum up,
With values inside a map, the ECU uses interpolation.
Outside the map, it uses last known value.

But if it does interpolation, it's not jumping through values.
Then why do you talk about jumps?

Perhaps they refer to the fixed/locked anchor points that are defined in the table.
The ones that you are adjusting.