goldnrust
West Midlands
Minimalist
Posts: 1,872
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Jul 16, 2020 13:38:50 GMT
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Sounds like youβve already thought of most stuff then ivanhoew! Putting it on the stim and bench testing it sounds like a good plan to me. Probably just a typo, but the Alpha-N tuning is TPS Vs RPM and ignores the map signal. In theory it can be tricky to tune for small throttle openings, and doesnβt cruise as well as using MAP vs RPM, but I definitely managed to get my Mx5 running cleaner overall on Alpha-N instead of the ITB mode, I think in part because it just simplified the process so much, meaning I could concentrate on getting the best tune with the simple tools I had rather than trying to understand how the complex tools were interacting.
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Jul 16, 2020 13:59:48 GMT
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Yes ,re the itb mode i find all the info on setting it to be gobbldygook , so just followed the instructions blindly lol. i was thinking that ,in general , map is easier for me to work with . i may well try the An mode as you say , just seeing if can fix tihs ego control problem first. of course it may be that the itb mode is massing with the code ,and so causing the prob . so, today ,new info , for my avid readers i compared a log with the old lm1 's to yesterday , and it appears it was doing this weird otherwordly behaviour with thm as well , here's a screenshot. not sure how clear it is , but the fainter lines are the lm's. next i did a test Graham suggested , where i barf a load of butane from my blowtorch ,up the pipes , to see if the sensors work in harmony with the ecu and dash read outs .. bit wobbly vid of test .. so now have ecu on table and testing it with the stim to see if what i am asking it do is just too much for its tiny pea brain. SOOO EXCITING ! regards robert
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Jul 16, 2020 19:49:16 GMT
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well i only went and made a couple more videos ...
Video 1 , where i try different afr's and watch the ego vary , and also experiment with the ego pid settings...
in no 2 , i try single wideband and other ideas ..
what did i learn ?
As far as i can tell , the ego control is not working correctly with two wide bands , but does work with one wide band .No idea why , or if i am right , but that's what seems to be the case from the videos .
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Jul 16, 2020 20:43:39 GMT
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.....I'm glad I'm stuck on Webers and a distributor ....yes I'm old school! But all credit for keeping us in the loop.
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goldnrust
West Midlands
Minimalist
Posts: 1,872
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Jul 16, 2020 20:49:27 GMT
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I agree it looks like dual PID is doing something a bit weird, but dual Simple is working exactly as it should. With simple, if your target is 13 AFR then once it sees richer than this is starts to pull fuel. In this example will pull 1% of fuel (set by the 'step size') every time a spark plug fires (set by 'ignition event per step') till it sees the AFR go richer than 13. It doesn't matter if the AFR reading is 12.99 or 9, it responds in the same way. And then when it goes lean, it responds in the same way but by adding fuel. 1% at a time till it goes rich again. In a running engine this results in it bouncing back and forth across your target, much like a narrow band set-up works on standard cars. With a correctly tuned step size and number of ignition events it can work pretty well and can keep you pretty close to your target, maybe bouncing +/- 0.2 AFR. I would normally use a ignition events per step of 20-50 and the the step size to 1-2%. What you can't simulate properly on the stim is that on a running engine the fuel it adds/pulls will result in a changed AFR creating that feedback loop. And so what you see if that once you set the AFR to leaner than target it just keeps adding fuel till it hits its maximum authority, as the AFR isn't responding to the changes that the EGO is making. As you've got the ignition events per step set so low, it does this very quickly and the step by step adding and subtracting of fuel is less obvious. It looks like the PID settings takes a more nuanced approach and if you're only a bit rich, it will only pull a little bit of fuel, and waits to see how the AFRs respond, which I guess means should reduce the bouncing / overshooting effect a basic feedback loop creates. So from that I'd say try it back o the car with the EGO set to dual wind band and simple See if helps.
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Last Edit: Jul 16, 2020 20:52:44 GMT by goldnrust
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i don't understaaaaaaand GNR if , on "simple" , i am at my target 13:1 afr , then ego corr should be set at 100% , eg no modifying of the injectors open time . However , it was sitting at either 125 % max deflection , or , if i came back the other way , at 75% min deflection ....
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.....I'm glad I'm stuck on Webers and a distributor ....yes I'm old school! But all credit for keeping us in the loop. thanks phil , i am a little worried this is all a bit too out there for most . I also like carbs n stuff . ..when i first built the tvr back in 87 , i was using two turbo's one blowing into another twin staged , with a dellorto 40 dhla side draught between the two turbo's . i spoke to the dellorto dealer matthew at contact dev in reading about it , and he called a bloke ,that was on the lotus development team for the esprit turbo , who told him i would never get it to work , went out a week or so later and ran a 13s 1/4 mile in 7 psi at avon .ok ok trumpet blowing over lol.
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goldnrust
West Midlands
Minimalist
Posts: 1,872
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i don't understaaaaaaand GNR if , on "simple" , i am at my target 13:1 afr , then ego corr should be set at 100% , eg no modifying of the injectors open time . However , it was sitting at either 125 % max deflection , or , if i came back the other way , at 75% min deflection .... I promise it's working correctly. Running on the stim you only get 1/2 the feedback loop, as the AFR doesn't change as a result of the ECO correction value as it would in a running engine, so you see what can appear to be a weird outcome. In 'simple' mode the EGO asks one simple question 'Is the AFR richer or learner than my Target?'. If its richer it reduces the current EGO correction by 1% (the step size you've set) and if it's leaner it increases the current EGO correction value by 1%. Then it waits a bit (the time period set by the number of 'ignition events per step') and then asks the question again. In your example on the stim, the target is 13. You've set the AFR to 15 and the EGO correction is pegged at 125% (set by your 25% authority value). Every time it asks the question 'Is the AFR richer or learner than my Target?' the answer is 'leaner' so it tries to increase the EGO correction by 1%. But it can't because it's hit your limit. As you set the AFR lower, at 14 it still reads lean so the same thing happens. You keep turning the AFR lower, down to 13.01 and it's still saying 'I'm leaner than my target so add EGO correction'. At 13.00 it will go 'Ok I'm at my target so the current EGO correction must be correct. Don't change anything. So the ECO correction in this example holds at 125% As you turn it down to 12.99 it says "I'm richer than my target so I must reduce the EGO correction by 1%. So the EGO correction now drops to 124%. Then it waits the number if ignition events you've set and goes through the same cycle and again it still reads lean so it drops to 123%. As long as you leave the AFR at richer than the target, it keeps going through this cycle till eventually it hits the 75% limit. Because your ignition events per step is set very low at 1, and the engine is 'running' at 3,000 RPM, it's making a 'step' every 0.003 seconds. So that full 50 steps from end to end of its correction scale takes 0.16 seconds. If you slow if down you'll be able to see it stepping. And you'll see it going through that routine of asking itself the question. In operation of the engine, when the feedback loop is complete it will find a natural point where every time it pulls 1% it goes lean, and then the next cycle it will add 1% and go rich. And so the ECO correction value will end up hovering somewhere in it's range and the AFR will stay very close to the target. If the step size and number if ignition events isn't tuned right then it will overshoot the ARF target and will bounce back and forth by a larger amount, which is where PID comes in. The PID takes a wider look and asks more complex questions. If you're a long way fro ,the target the PID will jump straight to a big ECO correction value ot get you back ot the target quicker. And as you get close to the target it only makes very small changes so it doesn't overshoot. Going back to PID.... writing this out I have a thought. Going back to your thoughts on overloading the memory available in the ECU, try setting the number of ignition events per step to a larger number, say 100. And see if it works. At the moment you're trying to run 2 PID calculations every time the engine fires a spark, which might just be too much. But the simple calculation is easier so maybe that's why it can cope and do 2 simple calculations every time it fires a spark plug ok.
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Ah thank you ,that makes sense , i have never used the simple setting on either car . With pid working ,i think i had it at 40 5 15 when driving it ,it is definitly the case that , if the engine is at 16:1 ,and i want 13:1 it can stick at 75% , so 25% lean , whereas it should be at rich correction .. if i set it for a single wb on the stim , it starts behaving as i would expect , your suggestion on the 100 events may be a game changer
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Jul 17, 2020 15:12:47 GMT
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maybe a bit of progress.. changing to 100 events per change , and changing the pid settings , which were actually at 15.5.15....seems to have had a dramatic effect ,and completely stopped the reverse correction i was getting ..now to try it on the car, i predict a bit of a pid loop surge fest with that much P... but i can play with it . i also created a graph , with lambda readout on the bottom ,from the wb slc 2's and the ecu and the dash afr readings up the side ,to see how closely my arrangement was mimicing the wb's.. i am pleased that the ecu is spot on , and i now know the dash is.5 afr lean. regards robert
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Last Edit: Jul 17, 2020 15:29:34 GMT by ivanhoew
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Jul 28, 2020 16:35:28 GMT
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bicester scramble vid from january 2020
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Jul 29, 2020 18:53:18 GMT
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I don't really understand very much of what you are on about - but I am learning a little from what you show. I would like to understand properly some day as it must be a great way of running the car.
I look forward to seeing what your changes bring in real life.
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Jul 29, 2020 18:59:36 GMT
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You won't understand it Mark because it's Venusian.
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Proton Jumbuck-deceased :-( 2005 Kia Sorento the parts hauling heap V8 Humber Hawk 1948 Standard12 pickup SOLD 1953 Pop build (wifey's BIVA build).
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Jul 29, 2020 19:46:18 GMT
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? I thought it was Medusian
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Jul 29, 2020 21:33:55 GMT
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Love how it draws crowds the moment you stop.
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Love how it draws crowds the moment you stop. It is good fun to see the reaction, and the freindliness of the people .
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Last Edit: Jul 30, 2020 7:23:41 GMT by ivanhoew
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Jul 30, 2020 20:02:09 GMT
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Well today dawned sparklingly blue and pristine , so i hoicked on my Gay M.T.B. Captain hat and shades , jumped in the old battlewagon , and shoved off for the shops . Put a tenner in at the petrol station , waited for photographers to finish , then off to lidl's for my first shop in 4 moths .spoinged out of the car like zebedee (magic roundabout) and donned my mask of secrecy ,shop was pretty empty , so whizzed around ,and all was well . Loaded it all in , fired up ,and drove out , waited at the lights then the roundabout ,and off i went down the straight to home ...er...well....not so simple...... Casually glancing at the dashboard i purloined off the Nautilus, i suffered a slight miasma of shock , my vision clouded, and i had to rub my eyes in that , american hero about to attack a J aircraft carrier in a sopwith camel.... sort of way.. Yup , my temp gauge for the 4.0 litre engine no .2......(normal reading 85c)..... was reading 112 degrees c ! ...my internal "god awlmighty" was interrupted when i then noticed the rad water pressure measuring device , was communicating the shocking out of this world fact , that the internal cooling pressure , instead of being the normal 5 to 7 psi , was ..wait .for .it.....wait for it.... TWENTY BLOODY FIVE PSI OF HEAD GASKET BLOWING GOODNESS ! At this point i realised i had not tuned the water pump on . After booking myself in for a thorough barbed wire flagellation session upon my return , i carried on fluffing the throttle to keep the engines as far below actual aluminium meltdown as possible , 1200 rpm at 45 mph , and watched the dash board for signs of hope . the rd pressure came down to 12 to 15 ....15psi is the cap blow off level ... front engine was at 95 , rear stayed at 110c .all...the...way...home..... drove in , hoofed the bonnet off , and got the garden hose on a "light fairy bath gossamer misting" setting (that's setting no2 in the instructions) , and wafted it over the blocks , upon which point the water droplets cracked off like fire crackers , bit like spitting in a hot frying pan ...it was hot. kept this up for 10 mins ,pressure dropped ,so also took off the rad cap , and trickled , very slowly , water in with the pump and fans on . bit the bullet , and fired her up (but in the normal way ) , and she sounded ok , no bubbling into the header tank , so maybe , just maybe i got away with it . i think , basically , i was driving with no water in the car , and a 11.6:1 compression ration , for about 5 miles ..... looking on the bright side , all the oil leak stains on the engines have disapeared ..it was so hot it burnt the oil right off and degreased themselves .. anyway , one fun fact i noticed on the log for the drive ... that timed section is me wheelspinning down standlake main rd in second gear , it goes from 2217 rpm , to 5220 rpm in 0.884 seconds ,,,,that's what you get with 7.6 litres of goodness , and only a 35 lb flywheel . I'll allow it regards robert
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Last Edit: Jul 30, 2020 20:12:41 GMT by ivanhoew
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Jul 30, 2020 20:38:15 GMT
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Brilliant, strap a whole trout in foil to the side next time it will be perfect when you get home π
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Brilliant, strap a whole trout in foil to the side next time it will be perfect when you get home π Now that's a good idea ,i realise i have those finned rocker boxes , i could do seared steak on those , baked potato's in foil on the headers , trout up against the block , hmmm what else ,, i reckon a nice tart..... rhubarb crumble behind the rads ?
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Brilliant, strap a whole trout in foil to the side next time it will be perfect when you get home π Now that's a good idea ,i realise i have those finned rocker boxes , i could do seared steak on those , baked potato's in foil on the headers , trout up against the block , hmmm what else ,, i reckon a nice tart..... rhubarb crumble behind the rads ? If youβre planning a long road trip maybe a slow roast shoulder of lamb π€£π€£
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