if goes lean shut of ignition or throttle

[abadi]

Hello guys,, 

is it possible to do this:

if the car goes leaner than target afr at load then shut off the throttle or cutoff the ignition. i wanna do that for safety.. 

how i can do it.. ?

 

[AbbeyMS]

Just configure lean trip in Engine protection ,  motor cal file needs to be spot on regards Target AFR and measure AFR for this to work correctly.

 

 

[abadi]

6 hours ago, AbbeyMS said:

Just configure lean trip in Engine protection ,  motor cal file needs to be spot on regards Target AFR and measure AFR for this to work correctly.

 

 

tried to find  lean trip in Engine protection but couldnt find it.. how to enable it.

 

[AbbeyMS]

On 12/7/2018 at 7:25 PM, abadi said:

tried to find  lean trip in Engine protection but couldnt find it.. how to enable it.

 

Send me CAL file I can configure it for you.

[Stevieturbo]

Such an actual engine protection feature does not exist, but you can create a low rpm limit based around load/lambda and base any cuts around this which will work ok. 

[MethOD]

I implemented something like this. I use a 3D table for my MAP limit.  X axis is AFR reading from the wideband.  Basically the leaner the reading, the lower the value I enter as the MAP limit.  I run methanol injection so in my case I made the Y axis the output from the methanol flow sensor because I want a higher MAP limit in relation to the amount of methanol that's being injected.

This works but it's not perfect since even a brief lean blip from a transient event causes the limit to trip.  It'd be nice if there was a way to incorporate a small delay before the limit kicks in.  I know you wouldn't want any delay for certain things, such as a genuine overboost situation.   But for lean trip I think it'd be nice to give it the ability to "overlook" the lean situation for a fraction of a second before fuel cut hits.

[TechDave]

11 hours ago, MethOD said:

This works but it's not perfect since even a brief lean blip from a transient event causes the limit to trip.  It'd be nice if there was a way to incorporate a small delay before the limit kicks in.  I know you wouldn't want any delay for certain things, such as a genuine overboost situation.   But for lean trip I think it'd be nice to give it the ability to "overlook" the lean situation for a fraction of a second before fuel cut hits.

GP RPM Limits have an activation delay for this.
Start up activation delay too.

[Mobilelpg]

I have setup something slightly similar using virtual auxiliaries.

If the wideband goes leaner than a set amount and RPM and TP are over a certain point it activates a warning light on my dash and starts a timer.
I then have an overlay table that starts adding fuel based on the timer.

This works well for me as at the start of the timer nothing happens so during a brief lean spike nothing changes however if it is a genuine lean condition due to something being wrong it will start adding fuel (percent added based on percent lean) and that is only if I haven't noticed that the light has been on for more than a second and reacted.

 

Edward.

[MethOD]

9 hours ago, TechDave said:

GP RPM Limits have an activation delay for this.
Start up activation delay too.

Can you explain to me how a GP RPM table would get set up for lean cut?

I am thinking that one axis would be the AFR reading, the other axis would be MAP and the values in the cells are the max RPM allowed at each point.  So cells that fall in the safe zone (i.e. no boost, any AFR/high boost, safe AFR) would have an RPM value of my typical RPM limit, say 7500.  Then cells that fall in the unsafe zone (high boost, lean AFR) would have a value of say 2000. 

From there I'd set the activation delay for 1/2 second. 

So if I'm at WOT and the engine is at 5500RPM and the AFR drops lean for more than 1/2 second, there will be an immediate 100% cut...until the RPMs drop to 2000 or the AFR comes back into line.  But realistically, I would lift as soon as I felt the cut, I wouldn't keep my foot mashed waiting for the parameters to come back.

Does this sound right?

 

[Adamw]

11 hours ago, MethOD said:

I am thinking that one axis would be the AFR reading, the other axis would be MAP and the values in the cells are the max RPM allowed at each point.  So cells that fall in the safe zone (i.e. no boost, any AFR/high boost, safe AFR) would have an RPM value of my typical RPM limit, say 7500.  Then cells that fall in the unsafe zone (high boost, lean AFR) would have a value of say 2000. 

Correct, except rather than your normal limit (7500) in the cells where you dont want cut applied (safe AFR), I would suggest you put something like 10000RPM, just so it doesnt interfere with your normal RPM limit.

[MethOD]

Ok, good point. 

Now then, what's the recommendation on the hard limit mode?  Ignition, fuel, or both?  My assumption is that either mode will cause a feedback loop where the AFR goes completely lean and thus cause the engine to stall out until the MAP and/or RPM drop down into the safe cells (which is what I'd want).