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Hentai's Wacked out Ideas 
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LQFP144 - On Top Of The Game
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The way that most stand alones are tuned and people understand how fueling works really disgusts me. Now I've only started learning and messing myself fairly recently. There are several people in this community that way ahead of me in understanding engines and tuning.

Stuff I dislike, the common idea of you go into boost you must run richer than stoich or 100kpa\WOT requires you go to richer than stoich
This idea leads to wasted fuel on daily driven vehicle with some add power. I've been after an ecu that allows for more flexibilty is this requard. Been thinking about basing fuel off TPS vs rpm or MAP vs TPS, IAT vs RPM, etc. When I say fuel I mean the commanded fuel not the VE table ( map vs rpm (SD)) or the MAF transfer function.

But like others have pointed out we have to deal with the ign timing from the changing fuel at the same points, I've seen GM deal with this via basing it off the commanded lambda adding in timing as lambda goes richer.

Lets get others input, say something, let me know what you think

Justin


Wed May 20, 2015 6:30 pm
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Quote:
Stuff I dislike, the common idea of you go into boost you must run richer than stoich or 100kpa\WOT requires you go to richer than stoich
This idea leads to wasted fuel on daily driven vehicle with some add power.


I mostly only tune race engines where fuel economy is not even a consideration so don't claim to be an expert but my logic would contradict yours...
My theory is to push a car along a road it is going to require a certain amount of torque, a common or easy measure of how efficiently an engine can produce that torque from the fuel would be BSFC. I have only needed to monitor BSFC on a couple of engines before but in my experience with a typical automotive type engine, minimum BSFC would rarely be achieved at air/fuel ratios of stoich or leaner than stoich. So I would say as a general comment if you are trying to push the car down the road with a tune that is as lean as it will possibly run then you are probably using more fuel than you would if the engine had been tuned to min BSFC.

Quote:
I've been after an ecu that allows for more flexibilty is this requard. Been thinking about basing fuel off TPS vs rpm or MAP vs TPS, IAT vs RPM, etc. When I say fuel I mean the commanded fuel not the VE table ( map vs rpm (SD)) or the MAF transfer function.


There are many ECUs available that give you the ability to put whatever parameters you want on the x & y axis of various comp tables or even the lambda aim table - Link, Motec, to name a couple.


Wed May 20, 2015 11:52 pm
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LQFP144 - On Top Of The Game
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adamw wrote:
Quote:
Stuff I dislike, the common idea of you go into boost you must run richer than stoich or 100kpa\WOT requires you go to richer than stoich
This idea leads to wasted fuel on daily driven vehicle with some add power.


I mostly only tune race engines where fuel economy is not even a consideration so don't claim to be an expert but my logic would contradict yours...
My theory is to push a car along a road it is going to require a certain amount of torque, a common or easy measure of how efficiently an engine can produce that torque from the fuel would be BSFC. I have only needed to monitor BSFC on a couple of engines before but in my experience with a typical automotive type engine, minimum BSFC would rarely be achieved at air/fuel ratios of stoich or leaner than stoich. So I would say as a general comment if you are trying to push the car down the road with a tune that is as lean as it will possibly run then you are probably using more fuel than you would if the engine had been tuned to min BSFC.

Quote:
I've been after an ecu that allows for more flexibilty is this requard. Been thinking about basing fuel off TPS vs rpm or MAP vs TPS, IAT vs RPM, etc. When I say fuel I mean the commanded fuel not the VE table ( map vs rpm (SD)) or the MAF transfer function.


There are many ECUs available that give you the ability to put whatever parameters you want on the x & y axis of various comp tables or even the lambda aim table - Link, Motec, to name a couple.


The goal isn't to lean out for gas mileage but not to change from running at stoichmetric just to accelerate the vehicle or because you enter positive pressure. At the racing side I understand going lap after lap requires enough fuel to make power and keep the cylinder cool enough not to cause pre ign or det. But I am talking in terms of a daily driven street car that shouldn't need so much extra fuel just to accelerate.

On the other item, I'm talking about completely open loop fueling, no closed loop control. iirc the lambda aim table will change the inj pw of the main fuel table in motec but otherwise its not gonna do it in a open loop way, either you apply the corrections or setup clsoed loop operation. Please correct me if I am wrong. I am interested in the link g4+ systems. Do you have recommendations on other systems that you use or used that you didn't list?

Thanks
Justin


Thu May 21, 2015 2:26 am
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Quote:
The goal isn't to lean out for gas mileage but not to change from running at stoichmetric just to accelerate the vehicle or because you enter positive pressure. At the racing side I understand going lap after lap requires enough fuel to make power and keep the cylinder cool enough not to cause pre ign or det. But I am talking in terms of a daily driven street car that shouldn't need so much extra fuel just to accelerate.
I still dont quite understand why you would need such unusual fuel strategies to achieve this though. Can you explain better what situations you have difficulty tuning using more traditional strategies? In my experience if all compensation maps are tuned correctly and all sensors are accurate and correctly located to give true conditions then in 95% of cases plain old SD with maybe at most a 4th overlay should be able to cover all typical running conditions for a basic street turbo car without many compromises. If you're doing compound turbo charging or twin charging or something more complex then I could maybe see the need for some extra dimensions?

What is your reason for not wanting to run closed loop? Even in touring car engines I would usually run closed loop under most conditions, that is the easiest way to take care of small mixture changes due to fuel temperature and many other minor variables like that. For a road car your fuel will be far more variable from tank to tank etc so I would think closed loop will be necessary if you want reasonably tight mixture repeatability.

Quote:
I am interested in the link g4+ systems. Do you have recommendations on other systems that you use or used that you didn't list?
I havent used Autronic for a long time but I'm fairly sure with the SM3 & 4 you can have about 4 fuel comp tables all with flexible x/y (Autronic was good 15years ago but in my opinion is too I/O limited today). Pectel, syvecs & Life racing are other ones I like - although less flexible in terms of load axes you can still do some fairly complex strategies using "multi-maps". This is where you have say 4 different S/D or A/N fuel maps and you span across them using some other variable.


Thu May 21, 2015 10:13 am
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QFP80 - Contributor

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Quote:
deleted

Undeleted by admin with the help of Hentai, thanks mate!

Original post, in full:
Quote:
Hentai wrote:
Stuff I dislike, the common idea of you go into boost you must run richer than stoich or 100kpa\WOT requires you go to richer than stoich

Justin




Take a look at my topic, I just do what you want... The numbers in my VE tables (you can choose 3 diffrent tables on the fly) are the opening times of the injectors in us (0,000001 second resolution) so it is up to you giving it not more fuel at boost. However you never reach the maximum power output of your engine this way (This happens always at a richer then stoich at full boost) you can or better must compensate this with less ignition advance (which you can also choose 3 diffrent tables at the fly)..

But I think you are thinking wrong... An engine which runs richer in boost can be more fuellefficient then a engine which runs
to lean under boost both develloping the same amount of hp........ think about that....


Last edited by LPGo on Fri May 22, 2015 11:23 pm, edited 1 time in total.



Thu May 21, 2015 9:40 pm
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LPGo wrote:
But I think you are thinking wrong... An engine which runs richer in boost can be more fuellefficient then a engine which runs
to lean under boost both develloping the same amount of hp........ think about that....

This. The engine will make more power when richer and more advanced (under load) therefore you don;t need to put your foot down as much to put your foot down to overtake. Running lean to save fuel ends up meaning you put your foot down more to actually get anywhere - and use more fuel anyway.

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Fri May 22, 2015 5:46 am
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LQFP144 - On Top Of The Game
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It really doesn't take that much power to accelerate up to speed just to waste 20% more fuel.

Going though some stuff
MAP vs EMAP - correction factor for changing VE from wastegate\VNT
lambda aganist IAT = correction factor aganist main ign table to alter how much more ign advance to add in based on how much richer fueling becomes

I am talking for a open loop standpoint in everything, the only thing changing lambda will be the commanded fuel table, not the VE table.

LPGo I don't see the point on having mutiple fuel maps in a true VE system unless you either have something changing actual engine VE.

Adam maybe unusal. I'm going for basically a control that keeps you around stoich unless you want more power, generally based on TP or torque demand. I am also trying to effect the fueling based on charge temp ( not the density factor ). For the most part on the street I hardly see the need to go lower than stoich unless you really start pushing it. For closed loop it would eventually be implemented but only after I get it close as possible to working correctly in open loop. I was interested in a life racing ecu but its more of a race ecu and inj pw fueling for sure, it could probably be done on it but take more time.

Image


Fri May 22, 2015 4:35 pm
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LQFP144 - On Top Of The Game
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For those that don't know, EQ is the inverse of Lambda


Fri May 22, 2015 4:36 pm
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QFP80 - Contributor

Joined: Sun Dec 07, 2014 5:27 pm
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Quote:
deleted by LPGo

Undeleted by admin with the help of Hentai, thanks mate!

Original post, in full:
Quote:
Hentai wrote:
LPGo I don't see the point on having mutiple fuel maps in a true VE system unless you either have something changing actual engine VE.



1 ve table as lean as possible
1 ve table as long as possible on stoich even at boost
1 ve table going immidiatly lower then stoich

if you want you can connect the 3 ignition tables also...

ve table 1 + igniton table 1 (low advance)
ve table 2 + ignition table 2 (slightly higher)
ve table 3 + ignition table 3 (most advance)...

isn't this what you want???


Last edited by LPGo on Fri May 22, 2015 11:24 pm, edited 1 time in total.



Fri May 22, 2015 5:01 pm
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LP, Go away. You clearly don't understand VE at all. Sorry dude.

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Fri May 22, 2015 11:08 pm
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