EcuFlash Glossary
Sep 12, 2007, 10:56 PM
#18
The high/lo timing 1,2 and 3 deal:
The ECU interpolates between (1 and 2) OR between (2 and 3) depending on a condition.
The condition *seems* to be to do with MIVEC advance - from looking at the code it appears that the ECU will use 1&2 when the MIVEC advance is increasing and 2&3 when the MIVEC advance is decreasing.
The point to this - when tuning you can either:
a) make the same changes to all 3 maps.
b) make changes only to #2.
There is no best way of doing it, I will say this thou, my alternate map patch (TBR) swaps #2 with another map. I do this because its less work to swap 1 map rather than all three, and it works just as well.
Now the interpolation between 1, 2 and 3 I suspect is averaging, ie if you have:
timing #1 200load, 3000rpm = *4
timing #2 200load, 3000rpm = *2
Then the result will be (4 + 2) / 2 = 3.
Thus if you are only making changes to #2 you will need to add much more (because of the averaging affect) timing to #2 than if you were making the same changes to 1,2 and 3...
Cheers
Dave
The ECU interpolates between (1 and 2) OR between (2 and 3) depending on a condition.
The condition *seems* to be to do with MIVEC advance - from looking at the code it appears that the ECU will use 1&2 when the MIVEC advance is increasing and 2&3 when the MIVEC advance is decreasing.
The point to this - when tuning you can either:
a) make the same changes to all 3 maps.
b) make changes only to #2.
There is no best way of doing it, I will say this thou, my alternate map patch (TBR) swaps #2 with another map. I do this because its less work to swap 1 map rather than all three, and it works just as well.
Now the interpolation between 1, 2 and 3 I suspect is averaging, ie if you have:
timing #1 200load, 3000rpm = *4
timing #2 200load, 3000rpm = *2
Then the result will be (4 + 2) / 2 = 3.
Thus if you are only making changes to #2 you will need to add much more (because of the averaging affect) timing to #2 than if you were making the same changes to 1,2 and 3...
Cheers
Dave
Sep 13, 2007, 07:51 AM
#19
There is definitely a bit of interpolation between the ignition maps ... I even see interpolation from the low octane maps with 0 knock and 100 octane rating. I'd see shifts of up to 3º at times.
While tuning I'd noticed that my timing didn't match my high octane maps in the higher load cells ... modifying the low octane maps helped with the problem ... the random ~3º shift is now only 1º every once in a while.
I still have safe low octane maps. If the low octane maps mirrored the high octane maps (a method some tuners use), this phenomenon would not occur. I'd rather be protected if I get a bad tank of gas and deal with a slight shift every once in a while.
While tuning I'd noticed that my timing didn't match my high octane maps in the higher load cells ... modifying the low octane maps helped with the problem ... the random ~3º shift is now only 1º every once in a while.
I still have safe low octane maps. If the low octane maps mirrored the high octane maps (a method some tuners use), this phenomenon would not occur. I'd rather be protected if I get a bad tank of gas and deal with a slight shift every once in a while.
Sep 13, 2007, 02:17 PM
#20
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For 03 evo 8 it starts decreasing octane number at 4 or greater knock sums if I remember correctly from my logs. Maybe it's different for other roms, like >6 that TouringBubble said.
Sep 14, 2007, 07:12 AM
#23
It's an auto-smoothing function. For instance, in your fuel map, if you have a jump from 11.0 to 9.0, you can use the interpolate functions to make it a smooth transition. Personally, I don't use those functions. They always screw my maps up.
I feel it's always best to interpolate by hand based on a few points you know are correct. It only takes a few minutes.
I feel it's always best to interpolate by hand based on a few points you know are correct. It only takes a few minutes.
Sep 14, 2007, 08:44 AM
#24
Account Disabled
acually its not that easy,that equation x1 +x2 / 2. is not how the ECU does it.
that is just an average equation.
The ECU uses a "Weighted Mean" equation
x(final) = w1x1 +w2x2 +w3x3+w4x4 / w1+w2+w3+w4
lets just do 2 cells for 1 map for now for simplicity.
say your actually load is 255, say on your map its between load 240 and 260
on your map 240 = 14 and 260 = 10
since 255 is more closer to load 260 than 240, its value weights more than 240.
i.e. 260 = 75% weight and 240 = 25% weight.
so using the equation. 14(25) + 10(75) / 25+75 which equals 11.
your way would equal 14+10/2 = 13.
But in real life the ECU uses 2 maps to interpolate the final value from timings maps.
if your between load cells , equation would take 2 cells from each timing map giving you 4 x's with the following equation.
using above values to represet map 1. just plut in x3 w3 x4 w4 from map 2.
14(25) + 10*75) + x3w3 + x4w4 / 25+75 + w3+w4
that is just an average equation.
The ECU uses a "Weighted Mean" equation
x(final) = w1x1 +w2x2 +w3x3+w4x4 / w1+w2+w3+w4
lets just do 2 cells for 1 map for now for simplicity.
say your actually load is 255, say on your map its between load 240 and 260
on your map 240 = 14 and 260 = 10
since 255 is more closer to load 260 than 240, its value weights more than 240.
i.e. 260 = 75% weight and 240 = 25% weight.
so using the equation. 14(25) + 10(75) / 25+75 which equals 11.
your way would equal 14+10/2 = 13.
But in real life the ECU uses 2 maps to interpolate the final value from timings maps.
if your between load cells , equation would take 2 cells from each timing map giving you 4 x's with the following equation.
using above values to represet map 1. just plut in x3 w3 x4 w4 from map 2.
14(25) + 10*75) + x3w3 + x4w4 / 25+75 + w3+w4
The high/lo timing 1,2 and 3 deal:
The ECU interpolates between (1 and 2) OR between (2 and 3) depending on a condition.
The condition *seems* to be to do with MIVEC advance - from looking at the code it appears that the ECU will use 1&2 when the MIVEC advance is increasing and 2&3 when the MIVEC advance is decreasing.
The point to this - when tuning you can either:
a) make the same changes to all 3 maps.
b) make changes only to #2.
There is no best way of doing it, I will say this thou, my alternate map patch (TBR) swaps #2 with another map. I do this because its less work to swap 1 map rather than all three, and it works just as well.
Now the interpolation between 1, 2 and 3 I suspect is averaging, ie if you have:
timing #1 200load, 3000rpm = *4
timing #2 200load, 3000rpm = *2
Then the result will be (4 + 2) / 2 = 3.
Thus if you are only making changes to #2 you will need to add much more (because of the averaging affect) timing to #2 than if you were making the same changes to 1,2 and 3...
Cheers
Dave
The ECU interpolates between (1 and 2) OR between (2 and 3) depending on a condition.
The condition *seems* to be to do with MIVEC advance - from looking at the code it appears that the ECU will use 1&2 when the MIVEC advance is increasing and 2&3 when the MIVEC advance is decreasing.
The point to this - when tuning you can either:
a) make the same changes to all 3 maps.
b) make changes only to #2.
There is no best way of doing it, I will say this thou, my alternate map patch (TBR) swaps #2 with another map. I do this because its less work to swap 1 map rather than all three, and it works just as well.
Now the interpolation between 1, 2 and 3 I suspect is averaging, ie if you have:
timing #1 200load, 3000rpm = *4
timing #2 200load, 3000rpm = *2
Then the result will be (4 + 2) / 2 = 3.
Thus if you are only making changes to #2 you will need to add much more (because of the averaging affect) timing to #2 than if you were making the same changes to 1,2 and 3...
Cheers
Dave
Sep 14, 2007, 01:34 PM
#26
Need to define the EGR solenoid control map, when it's energized.
Nevertheless:
Boost Enhancement Adv/Ret map 1 and map 2 has nothing to do with boost.
Map 1 is defaulted to neutral, and map 2 advances timing at low/mid RPM and load (cruise). Probably to assist lighting the cat or something from pushing the CO2 (from extending combustion of remaining CO, CH's and O2). Or maybe it works harmoniously with the EGR gasses but it would be tough to tell if the EGR maps aren't defined.
Who knows? I don't
Nevertheless:
Boost Enhancement Adv/Ret map 1 and map 2 has nothing to do with boost.
Map 1 is defaulted to neutral, and map 2 advances timing at low/mid RPM and load (cruise). Probably to assist lighting the cat or something from pushing the CO2 (from extending combustion of remaining CO, CH's and O2). Or maybe it works harmoniously with the EGR gasses but it would be tough to tell if the EGR maps aren't defined.
Who knows? I don't
Oct 13, 2007, 09:14 PM
#30
hey Jim,
Its a bit confusing - I will try to summarise.
In the IX ECU there are 2 processes that go into calculating the final timing value
1) Because there are 3 high octane timing maps the ECU has been coded to interpolate between 1&2 or 2&3 depending on what appears to be the MIVEC advance/retard
2) Once the ECU has decided which timing map to use it used a weighted averaging algorithm inside the map to interpolate between cells, very basically if you had a map that specified 0 timing for load 0 and 10 timing for load 100 then the result for a load of 50 would be??? 5! what would the load for 70 be? 7 etc etc
HTH
D.
Its a bit confusing - I will try to summarise.
In the IX ECU there are 2 processes that go into calculating the final timing value
1) Because there are 3 high octane timing maps the ECU has been coded to interpolate between 1&2 or 2&3 depending on what appears to be the MIVEC advance/retard
2) Once the ECU has decided which timing map to use it used a weighted averaging algorithm inside the map to interpolate between cells, very basically if you had a map that specified 0 timing for load 0 and 10 timing for load 100 then the result for a load of 50 would be??? 5! what would the load for 70 be? 7 etc etc
HTH
D.