NefMoto

Technical => Tuning => Topic started by: rajivc666 on January 17, 2012, 09:20:14 AM



Title: Lean Burn
Post by: rajivc666 on January 17, 2012, 09:20:14 AM
I was trying to make a tune which will run leaner than stoic at about less than 65% load and lower than 3000 rpm. Along with LAMFA ,KFLBTS,KFFDLBTS( ZEROED out as required) also modified map LAMLGMTM (lambda limit lean) . But from the diagram on page 729 of 1327 of english funktionsrahmen module it looks like me7.x is coded not to exceed lambda 1. Looks like a job for reverse engineers. Whatever I do the car wont run leaner than stoic. Is there any way around or do i have to modify some other maps?.
Thanks


Title: Re: Lean Burn
Post by: rajivc666 on January 17, 2012, 09:43:53 AM
Looks like I have to modify LASOAB (lambda for catalyst protection) and may be many  more maps I will update as an when I   find out. I dont have a running car as it was the victim of my tuning so have to wait for the weekends to try out my maps on my brothers car  ;D


Title: Re: Lean Burn
Post by: phila_dot on January 17, 2012, 11:06:17 AM
It is not really practical without  custom code. Lambda will follow the richest input so they all would have to be lean. Also, there are hardcoded default values of Lambda 1, so all of the condition bits would have to be set. Also the lean limit would obviously have to be raised

Possible maybe, practical no.


Title: Re: Lean Burn
Post by: Rick on January 17, 2012, 12:47:07 PM
easy, disable closed loop, tune fuel maps.


Title: Re: Lean Burn
Post by: nyet on January 17, 2012, 01:03:49 PM
What is the easiest way to disable closed loop?


Title: Re: Lean Burn
Post by: phila_dot on January 17, 2012, 01:34:01 PM
easy, disable closed loop, tune fuel maps.

This doesn't make sense to me.

It isn't correction thats the problem. The problem is you cannot target lambda > 1.


Title: Re: Lean Burn
Post by: julex on January 17, 2012, 04:05:36 PM
there is a 2d map that maps o2 voltage to lambda which is then used my ME. Needlessly to say shifting axis will give you what you want. Just keep in mind that these narrowband o2s are quickly outside of measurable range once pushed out more than 0.1 lambda or even less.

Don't ask about the map name, I don't know. I saw it though in RS4 winols definition file when I was looking for other stuff.


Title: Re: Lean Burn
Post by: phila_dot on January 17, 2012, 05:02:27 PM
there is a 2d map that maps o2 voltage to lambda which is then used my ME. Needlessly to say shifting axis will give you what you want. Just keep in mind that these narrowband o2s are quickly outside of measurable range once pushed out more than 0.1 lambda or even less.

Don't ask about the map name, I don't know. I saw it though in RS4 winols definition file when I was looking for other stuff.

It's LALIUS.

No offense, but that sounds like a terrible idea IMHO. Also, that would require closed loop operation.


Title: Re: Lean Burn
Post by: sn00k on January 17, 2012, 05:11:07 PM
LALIUS - Lambdalinearisierung, LSU-Sonde vor Katalysator (22x1)

well, you could shift this axis.. but you would have to tune lots of maps to get everything working as intended again..
ie enrich everywhere.. so later when later you request afr 14.7, you really get ie afr 15.5.

its a good map to have tho, i added it a few days back to my own definitions file.
i was looking into using e85 for a tune, and you can save some fuel if you run this pretty lean and add timing.


Title: Re: Lean Burn
Post by: phila_dot on January 17, 2012, 05:24:02 PM
LALIUS - Lambdalinearisierung, LSU-Sonde vor Katalysator (22x1)

10x1 in ME7.1 (narrowband)


Title: Re: Lean Burn
Post by: rajivc666 on January 17, 2012, 11:36:23 PM
Thanks LALIUS is a nice map to have  ;D. My guess is that modifying it will lower the fuel trims which in turn will lean the AFR. But would be nice to remove the restriction  in the code itself, will have a look at it but with my current skills it is going to take time. But why is bosch so adamant on lambda, is it to protect the catcon or does it have some other repercussions.   I remember reading an article which said higher EGT is not the problem with leaner AFR as further it gets from stoic the EGT trails off quickly, But the excess oxygen with high temperature of combustion tend to oxydize or burn the aluminium Pistons, Dont know about forged pistons thou.


Title: Re: Lean Burn
Post by: Giannis on January 18, 2012, 10:57:58 AM
How lean are you planning to go? There is a map called lambda for start and after start or something i don't have my laptop at the moment. It has 2 temperature axis and is 12x12 i think. One time i was playing with it i managed to request lambda less than 1.00.


Title: Re: Lean Burn
Post by: phila_dot on January 18, 2012, 11:34:19 AM
How lean are you planning to go? There is a map called lambda for start and after start or something i don't have my laptop at the moment. It has 2 temperature axis and is 12x12 i think. One time i was playing with it i managed to request lambda less than 1.00.

Lambda < 1 = enrichment


Title: Re: Lean Burn
Post by: Rick on January 18, 2012, 01:14:39 PM
This doesn't make sense to me.

It isn't correction thats the problem. The problem is you cannot target lambda > 1.

I think it makes perfect sense, think about what you are trying to achieve, and where you are trying to achieve.  I've a number of cars running this setup and there are measurable gains in economy to be had.  I wouldn't touch lambda sensor calibration though!

Rick


Title: Re: Lean Burn
Post by: phila_dot on January 18, 2012, 01:37:09 PM
I think it makes perfect sense, think about what you are trying to achieve, and where you are trying to achieve.  I've a number of cars running this setup and there are measurable gains in economy to be had.  I wouldn't touch lambda sensor calibration though!

Rick

How do you get Lamdba > 1 by disabling closed loop?

Target AFR will still be <= 1.


Title: Re: Lean Burn
Post by: Rick on January 18, 2012, 01:43:31 PM
KFLF.  The ECU will still think it is at lambda 1, but that isn't an issue at low loads and rpm.

Rick


Title: Re: Lean Burn
Post by: julex on January 18, 2012, 08:38:20 PM
Another way to do it is by using narrowband feed from zeitronix or innovative (it if supports that). I have zeitronix and I know that you can program it to skew actual readings towards either lean of rich by a large amount. Zeitronix then is wired in place of O2 sensor and ECU thinks it is using actual o2 narrowband sensor while it is actually zeitronix that is feeding it the data.

The setup of the new stoich is called "Switching point". You can set it to anything between 9.7 to 20.7 ... so you can choose your new stoich and the zeitronix will be simulating happy 14.7/1.0 sensor while in reality it tell ECU to stick to your chosen value.

I have no need to do any schenanigans like that but since you do.. maybe you can pioneer the way for rest of us :)


Title: Re: Lean Burn
Post by: phila_dot on January 18, 2012, 09:22:14 PM
KFLF.  The ECU will still think it is at lambda 1, but that isn't an issue at low loads and rpm.

Rick

So you are using RLLRUN to disable closed loop and KFLF to manipulate fuel.

How reliable is KFLF? I ask this because it is not a target Lambda and it goes through so many other influences.


Title: Re: Lean Burn
Post by: Giannis on January 19, 2012, 06:31:55 AM
Lambda < 1 = enrichment
sorry i meant leaner than lambda 1 but it works!
Regards