Author Topic: TPS weigh for ref DC  (Read 21345 times)

Offline GintsK

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Re: TPS weigh for ref DC
« Reply #15 on: November 07, 2010, 02:21:52 pm »
Log file contain config. I suggest to switch off anytrim during current phase. when your PID will be sorted out and some potentiometer connected to analogue input then setting will be anytrim ready.

About fueling: VEMS calculation include Lambda table. Even if EGO is off, calculation takes value from lambda map as additional multiplier. Now if you change lambda value at 140Kpa, you change all fueling above this value.

Please take Mattias config as basement. You have many misconfiguration in your config.

Offline AVP

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Re: TPS weigh for ref DC
« Reply #16 on: November 07, 2010, 02:27:16 pm »
my map was done by marc swansson specifically for my car.

So basically you mean that my lamda table cannot be done the way i have it? i ought to have a value of my top rpm and kpa in order to use the values i need on those areas?

that negates the whole reasoning of having a small lamda table as 'you dont need one since EGO is off above boost values'!

that is such a stupid thing to do in the firmware. than means that i loose part of my lamda table which i need for cruise...


As for the Boost:

so anytrim off, and use the PID for now to try and see how it responds, then try and get the anytrim for minor changes, correct?

Offline AVP

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Re: TPS weigh for ref DC
« Reply #17 on: November 07, 2010, 02:50:46 pm »
what other misconfiguration can you see?

Offline GintsK

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Re: TPS weigh for ref DC
« Reply #18 on: November 07, 2010, 03:46:10 pm »
what other misconfiguration can you see?
In my opinion: first of all MAT/TPS table - good chance to melt pistons at colder weather. Lambda map. Warmup, +then cranking as result, rpm/map correction should be 100 not 0, acceleration enrichment dotrate...

Lambda map is small because no one has necessity for more than one area with rapid lambda changes.
Like on any other map, ECU takes border value if engine operates outside its area. It is possible to leave table as it is, but it is not correct way: VE table is "true" until 140Kpa. Above it will be disturbed because it describes mixture requirements  of engine, but it is not purpose of it. Purpose is just to describe volumetric efficiency. Lambda table is for mixture description. For both: real time mixture calculation and target for closed loop control.

BTW in MS2/3 also is possibility to involve AFR table in fuel calculation. Very usable solution!

Gints

Offline AVP

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Re: TPS weigh for ref DC
« Reply #19 on: November 07, 2010, 04:31:46 pm »
1) MAT/TPS

why should there be a problem with colder weather? This is how the car has been running on megatune and also much higher advance on colder weather than what i have. My ignition timing table is the single thing that is most accurate so far, so there should not be a problem there. Most of the times, on cold weather, at least on megatune the car was richer running only on the VE table.

2) What is the problem with warmup enrichment?

car starts fine and holds lamda 0.90-0.95 until the designated 100 value. Then it goes as the VE table. why should there be a warm up enrichment above 60C CLT? the engine is already warm!

3) Lamda:
i changed the table so i can include the 320kpa line with the 0.80 lamda values that i want. However since i require 0,80 lamda from 270kpa and above, if i use the 270kpa value there instead of the 320, does that mean that from 270 and above VEMS will make it 0.80 anyway? or at least take it into account?

4) what do you mean rpm/map correction?

5) what is wrong with the accel dotrate? it seems to be working fine so far. was quite higher and now much better.


Offline GintsK

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Re: TPS weigh for ref DC
« Reply #20 on: November 07, 2010, 05:20:24 pm »
1)In MS temperature relation is hard-coded. Here it is upon to user.

2)8% of enrichment @0degC is definitely too less. This is amount of enrichment usually required @50degC. It can be +/- some % but not 20% assuming usual gasoline is used.

3)Yes. You can see it now in your log file - it takes top line from present table at boosting.

4)MAP correction table. I am not sure is it important, but this is how it was described when table was introduced.

5)Every time when AE  kicks at slow TPS movement it gives too much fuel. You can see it in log: after each PW spike mixture becomes rich.

Offline AVP

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Re: TPS weigh for ref DC
« Reply #21 on: November 07, 2010, 05:30:45 pm »
ill do it the other way around

4) i have been trying to reduce that gradually. i cannot put 100. 101 is the minimum. Should i reduce the scale on the rpm vs amount instead? Or should i just put the middle scale in the amount even higher?

3) I have no idea what the map correction table represents. Is anyone else using this ?

2) If i put 120 there what happens is that the lamda goes to 0.85 or even less on idle and the car stumbles. I am not sure why, but although everything is properly calibrated, it seems way too rich to use larger values than that.Have you tuned an audi 2.2 engine before?

1) In megatune, i dont recall that there is a specific curve for the MAT vs TPS which is why we had to use the warm up enrichments for this purpose. The curve which was hardcoded was the ignition retard. If that is what you referring to, then i have already answered.My timing is right. My motronic had 22deg advance on full boost and gave +3deg for MAT below 18C. mine is much more safe than that.


now i did another couple of runs, lamda now reaching 0.75 on high boost, so i fixed the VE there. I do still get some oscillations from the solenoid although anytrim is off. My PID is close to Mattias on these runs: 220/35/50. I am going to try using higher I than D next time.

Offline GintsK

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Re: TPS weigh for ref DC
« Reply #22 on: November 07, 2010, 06:04:15 pm »
4) I think we misunderstood each other. I mean MAP corr table. You have 0 everywhere, should be 100.

+3) It was introduced at fw 1.1.48 http://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChanges

2) My guess: may be your injector characteristics are wrong? Then multiplying goes wrong at small PW. This is not about particular engine but about fuel evaporation.

1) MAT/TPS curve describes air density vs air tepmperature using ideal gas law. As second it is usable to compensate heat soak and other influences. It relates only to fueling, not ignition. I meant in Megasquirts was hardcoded in s19 files. also in older VEMS firmwares it was so. Last 2 years VEMS use this table from ~1.1.4x or so. Take it from Mattias config.

It is interesting about 22deg. I see you have this amount of advance. Here I am forced to use somewhat like 18deg@260Kpa on 20VT or sometimes even less due to knocking. We have not so good fuel maybe.
« Last Edit: November 07, 2010, 06:19:43 pm by GintsK »

Offline AVP

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Re: TPS weigh for ref DC
« Reply #23 on: November 07, 2010, 06:19:11 pm »
injector characteristics are filled in as they shoulld. Siemens deka 630cc@ 3bar. I use 4bar fpr.

used the VEMS multiplication to come up with the 3.1req_fuel and i also reduced it to allow for more VE values between different lamda equivalents.

MAT vs TPS table.

my usual runs here in the UK due to cold weather are giving me between 10-25C MAT. On those areas on the VE specific table i can put in the value required to give me 0.82-0.80 lamda which is what i have been using. Now most of the times i have seen that if MAT is lower than that, my lamda stays 0,80. So if i start increasing the table on this MATvs TPS as per ideal gas law, then all my mixtures will become much more rich. If i were to leave them as they are, shouldnt i be seeing the lamda going leaner? If it is not, then maybe for the MAT from 10 and above, i dont need to add more fuel. I can put something for -40 value which is a value that will never occur anyway, but i havent yet seen any circomstance other than MATs getting really high(heatsoak) that i need more fuel.

In that sense, my car struggled with megatune once when the MAT was in the 35 region and although the VE table was perfect, it was getting too lean. According to the ideal gas law, if i were to be using this table, the car would have been in even leaner state!

So dont you think that this table is something that needs to be accomodated depending on where the engine is operated? different temps in the UK, canada, different in Greece, or africa. For each climate we use the 100 value on areas that the car is mostly operated and then adjust for the extremes. Maybe that is why my car is ok for this colder climate BUT as soon as it gets warmer it seems lean. Because if i was tuning it in Greece, which is hotter in general, the opposite would have happened.

on your point 5 goes my previous remark about the AE. What do you think i should do to reduce the large amount of enrichment on low pedal presses?

Offline GintsK

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Re: TPS weigh for ref DC
« Reply #24 on: November 07, 2010, 07:25:04 pm »
Lower required fuel is not problem. I also use same trick.

But I am not sure about injector. You have 192us effRampup and 4080 for batt compensation gives just 0.099msec of injector lag time @13V. In reality it is much higher! Somewhat like 0.6msec.

Generally warmup multiplier should affect just real injection time. Now it multiplies some additional ~0.6msec.

e.g electrical PW is 1.5ms. Real PW for fueling calculations should be 1.5-0.6=0.9ms.
Now it is 1.5-0.1=1.4ms
At 120%  WU first case gives 0.9*1.2=1.08ms
second (your) case gives 1.4*1.2=1.68ms

As result WU becomes overscrewed at small loads. Same with other multiplicative corrections.

What relates MAT table. Just take a look on Mattias table. It tells pretty much everything. And with small tweeks it works at our -20...+30degC. I see your climate is much more softer :)

Gints

Offline AVP

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Re: TPS weigh for ref DC
« Reply #25 on: November 07, 2010, 07:29:43 pm »
the MATvs TPS table is also related to injector size, correct? Mattias is using 190cc injectors on that config and im using 630cc. Thats a huge difference, and believe me if i put 119 on that table or 110, my car will stumble and spit out the extra fuel.

as for the rampup etc i will speak to Marc about it. I have no idea about the equations. Base settings are a bit too complicated for me and will get me in trouble if i start changing them on my own.

Having said that, if i change those settings, that will mean that all my VE table will become leaner again, and would have to be increased, correct?

Offline AVP

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Re: TPS weigh for ref DC
« Reply #26 on: November 07, 2010, 07:31:25 pm »
Honestly do you ever see -20C IAT?????

Offline GintsK

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Re: TPS weigh for ref DC
« Reply #27 on: November 07, 2010, 08:09:06 pm »
MAT table is absolutely unrelated to injector size. It is related more to air mass measurement/calculation passing to engine. MAP sensor measures just part of main measurement, just in connection with MAT senor and using this table is possible to determine air mass and as result inject right amount of fuel.
But yes, here is multiplication again...

Last winter I clearly remeber days with -16C and clean dry asphalt. My n/a feels like plus 30hp.
We had days with -25 in the morning, but then was traction problems :D :D
« Last Edit: November 07, 2010, 08:13:06 pm by GintsK »

Offline AVP

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Re: TPS weigh for ref DC
« Reply #28 on: November 07, 2010, 08:33:37 pm »
its different -25 ambient to -25 IAT, esp in a normal aspirated car without an intercooler.

but anyway, for the multiplications then what is your recommendation? Is the 192 number too small?

i thought that things were simple in VEMS, and whenever there is a mention of fuel and VE the numbers are having something to do with the main VE so as things are kept simple!

anyway, i did another simple test and realised that warm up enrichments are now needing to be a bit higher, so i adjusted them.

boost still oscillates somewhat, even with mattias PID control. I am using a turbosmart solenoid which originally was said to me that i should use it with 16ms. I tried that and boost comes up too slow. now trying 21ms but oscillates

Offline GintsK

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Re: TPS weigh for ref DC
« Reply #29 on: November 07, 2010, 10:02:22 pm »
When cruising out of the city IAT and ambient are nearly the same. City traffic is different story. But at -25 streets are empty, driving is like on highway if you are lucky to start engine :)

something like 400....500should be configured for opentime@13.2V Or 192 ~5times higher. But then retune of all VE will be necessary.

VEMS grows. Much of simple things are not so simple. In overall this ECU comes better and better. But weak documentation is already tradition.

Back to boost  ;D
Did it oscillates with PID 0/0/0 ?
I have two strategies to find good values: 1)start with aggressive PID like in Mattias config and then find right values for DC table 2) opposite with 0/0/0 find right DC values and then add some soft PID control.
Second strategy is better for internal w-gates and if it is hard to eliminate oscillations.
sometimes oscillations stays even with plain DC. It means some mechanical fault in W-gate. sticking, too high internal friction.