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AbbeyMS

Closed Loop fuel trims

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We use Syvecs (Life) ECU's and within the closed loop set up we can you can set up different trim conditions

different % limits for  adding fuel + and removing fuel - so you can remove a small percentage and add a large percentage

different % limits for full throttle and part throttle ( uses a throttle percentage number to set up low load/high load condition)

This will allow you to run closed loop 100% with different trim levels for low and high load.

 

Thanks

 

 

 

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Plus one for that. 

I would like to have two  2d or 3D table. One for additiv and one for subtractive. 

I recently startet to use full time closed loop. It works great. Just the proportional table is set complet the wrong way in the base maps. 

I spent alot of time into the frequency and Gain table. Gain must be higher at low error and visa versa. Otherwise control algorith is not stable. 

And i like to add.  Please make an axis option on all fuel correction tables for traget afr.

Openlooop Target AFR and Openloop Target Overlay is not enough to adjust target afr for all conditions. 

For example i like to change AFR for the follow conditions: cold start, warm up, high IAT, very igh load situations, top speed runs, etc. 

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6 hours ago, motor said:

we need CLL PID

Don't agree. The base map is just tuned complet the wrong way. I've done a lot of testing you want big corrections at small errorrs and smaller corrections at bigger errors. 

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2 hours ago, mapper said:

Don't agree. The base map is just tuned complet the wrong way. I've done a lot of testing you want big corrections at small errorrs and smaller corrections at bigger errors. 

Can you elaborate a bit please? Got an example of what kind of tables you use?

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8 hours ago, MagicMike said:

Can you elaborate a bit please? Got an example of what kind of tables you use?

are we again looking at the Syvecs Closed loop fuelling strategies?  The ability to have different closed loop trimming parameters in relation to engine load?

 

Thanks

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Regarding Lambda control error correction table. I spend alot of time to tune these. The base map is adjusted the wrong way around. Because the error correction tables is a % corretion of actual error, you want big corrections like 15%  on small errors (0.03 lambda error) and small correction (like 5%) at the biggest error on the table. This is because a fuel film built up first in the ports when big correction are applied. This means it needs several burn cycles to get the whole change applied and measured. This means lambda control applies big changes two or three times for big corrections which leads to Lambda oscillation.  On small changes fuel film built up is much less.  Lambda change is done and measured much faster and within same burn cycle. This means the Lambda correction can be set much higher, because the change in AFR is measured instant.

I have attached a tuned example.  

Closed_loop_settings_link.JPG

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On 10.12.2017 at 5:11 AM, Ducie54 said:

That is opposite to what HPA teaches and the help file. 

I now it's the opposit what the manual says. I was skeptic too when i tuned it, but at the end of the day you have to adjust the numbers so that  the result are good and not like what you may think should work. And with the explanation in my last post, I think my tuned example makes sense at all. 

Try it and you are going to see, that my settings work much better than the other way arround! 

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I'm experiencing the oscillating adjustment with CLL with an aftermarket Wideband, not a CAN link.

I've adjusted map to match your numbers. will upload before journey home from work and see if it improves.

worst time for me is in stop go traffic, when lightly on throttle in first gear, crawling along. car starts to jump when CLL turned on with current setup (below). will report back later :)

 

image.thumb.png.8f84a30138cd70e6098bb175cfea3376.png

 

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That's really interesting Mapper, I've been meaning to have a play with that CLL gain table but havent yet. 

I think you've just piqued my interest however! 

I'll try those other numbers for a starter and see how it differs.

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so I've implemented this. no other changes.

initial observations on driving.. through the lambda gauge, not through Link software..

AF ratios settle much quicker, and remain constant.

I have idle AF set a little richer to give better idle, I might change this leaner now as it appeared much more stable than previously

below 3k rpm, low gears in traffic on neutral throttle there remains an oscillation although reduced in amplitude, but the wavelength has been increased dramatically. previously this would occur every 0.5 secs, now approx every 1.5 sec.

I'll check the ecu log when I get the chance and compare.

 

cheers

Marc

 

 

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2 hours ago, MarcD said:

so I've implemented this. no other changes.

initial observations on driving.. through the lambda gauge, not through Link software..

AF ratios settle much quicker, and remain constant.

I have idle AF set a little richer to give better idle, I might change this leaner now as it appeared much more stable than previously

below 3k rpm, low gears in traffic on neutral throttle there remains an oscillation although reduced in amplitude, but the wavelength has been increased dramatically. previously this would occur every 0.5 secs, now approx every 1.5 sec.

I'll check the ecu log when I get the chance and compare.

 

cheers

Marc

 

 

Hi Marc

Good to hear back from you. How much does your AFR oscilate? Where is the wideband located? Depending on position, you need to adjust Lambda rate and Gain. 

You should do some testing. Tune your VE table with CLL off  as good to your Target AFR as possible. Adjust your target AFR table to the rich side with one task by the amounts listed in the gain table 0,33 0,66 etc. And log, with a high logging rate, how long the sensor needs to get to a stable reading. 

Lets say it needs 0.3 seconds. This means your frequency in the lambda rate table may be max. 1/0,3  = 3.333

This test should be done at different loads and rpms to work out best CLL settings. Best place to do that is a load bearing dyno. 

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