Decel Cut - throttle position

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Mattias
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Decel Cut - throttle position

Postby Mattias » Fri Jun 30, 2017 6:59 pm

My engine is suffering from some oil consumption during decel and I think it's from the valve guides and/or blow-by created by the vacuum in the cylinders. I have an idea that it might help to open the throttle while decel cut is active.

On a side note, could anti lag be configured to test this ie, map 100% fuel dis-enrich?

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HaltechMatthew
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Re: Decel Cut - throttle position

Postby HaltechMatthew » Mon Jul 03, 2017 1:33 pm

Map your Min Throttle in the Idle Control section. It is 3D so make it against the Decel cut.

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Re: Decel Cut - throttle position

Postby Mattias » Tue Jul 04, 2017 6:44 am

HaltechMatthew wrote:Map your Min Throttle in the Idle Control section. It is 3D so make it against the Decel cut.


Thanks Matt, I had to add DBW Acc. on the other axis to remove a jerk when decel turns off but it works perfect and smooth as long as I leave decel by applying throttle. If I just slow down until decel is turned off I still get a jerk before the throttle catches up. I also tried to map against decel ign retard and fuel corr. but those happened to late so it didn't work as good.

I now have zero vacuum in the manifold on decel with 30% tps so hopefully it will reduce oil consumption and risk of knock when going wot after decel.

I think this would be great option to add to the decel function so desired vacuum level can be achieved on decel.


Decel throttle.JPG

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Re: Decel Cut - throttle position

Postby HaltechMatthew » Tue Jul 04, 2017 2:50 pm

You may need more retard to take the torque away when fuel is resumed. Attack will feed it back in.

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Re: Decel Cut - throttle position

Postby Mattias » Tue Jul 04, 2017 4:15 pm

HaltechMatthew wrote:You may need more retard to take the torque away when fuel is resumed. Attack will feed it back in.


I'll try and see if it makes a difference.

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Re: Decel Cut - throttle position

Postby Mattias » Tue Jul 04, 2017 10:46 pm

I had a chat with an engine technical expert at work today and this is a known problem causing high oil consumption. On OEM ECU:s throttle position is mapped against RPM during decel to hit a target vacuum curve.
So an additional 2D map for throttle opening in the decel function would be very useful :)

I guess it should also help cool things down bit to have some air flow trough the system on decel.

BR,
Mattias

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HaltechMatthew
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Re: Decel Cut - throttle position

Postby HaltechMatthew » Wed Jul 05, 2017 4:19 pm

Too complicated for general use. Maybe if we made OEM ECUs it would be considered. At best you can map the min idle as already suggested, or perhaps fix the engine.

Before you add more requests you have to consider this is a generic use ECU primarily used for motorsport. Street use is secondary and the ECU is never advertised as being a street legal ECU (even though it can be done). There are millions of cars with no DBW and no idle control and they dont have issues with oil consumption.

More a poor PVC hardware design I would say, much like my old and long sold 2.0TFSI engine that used more oil for fuel volume from new than any 2-stroke engine I have ever owned.

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Mattias
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Re: Decel Cut - throttle position

Postby Mattias » Wed Jul 05, 2017 5:12 pm

HaltechMatthew wrote:Too complicated for general use. Maybe if we made OEM ECUs it would be considered. At best you can map the min idle as already suggested, or perhaps fix the engine.

Before you add more requests you have to consider this is a generic use ECU primarily used for motorsport. Street use is secondary and the ECU is never advertised as being a street legal ECU (even though it can be done). There are millions of cars with no DBW and no idle control and they dont have issues with oil consumption.

More a poor PVC hardware design I would say, much like my old and long sold 2.0TFSI engine that used more oil for fuel volume from new than any 2-stroke engine I have ever owned.


Yes, engine will be refreshed before next season when I will be entering a TimeAttack series, but before then I want to work out as many kinks as possible.
This is not a street problem unless you live in the swiss alps or something, as I see it it's at its worst on circuit driving where I go between WOT and decel all the time.

PCV is also on the list of improvements, but to solve this I'd probably need to go for dry sump or vacuum pump.

Most of my requests are born on the tracks where I push the car to the limit. The only issue I have on normal street driving is some idle control issues. Most people that ride in my car on the street are amazed how oem like it behaves on normal driving so the Elite works very well in that sense :)

I think most of the requests I've done here have been for additional generic functionality to aid custom setups that are often needed in motorsport to control whatever setup is needed.

I also tried to add more retard to the decel and it works pretty good, no big jerks, only some exhaust pops but that's no issue. So thanks for the tip!

BR,
Mattias

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Re: Decel Cut - throttle position

Postby HaltechMatthew » Thu Jul 06, 2017 11:19 am

The problem is the small requests take time. Time that could be spent on, lets say, adding auto transmission support, or throttle blipping, or cruise control, or many other far more important features. Limited engineers and limited time, with many projects being worked on.

What you need more is probably a dashpot function, which feed the airflow shut as you lift off either through DBW or idle control. Already on the list for when we have time.

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Re: Decel Cut - throttle position

Postby Mattias » Thu Jul 06, 2017 5:46 pm

HaltechMatthew wrote:The problem is the small requests take time. Time that could be spent on, lets say, adding auto transmission support, or throttle blipping, or cruise control, or many other far more important features. Limited engineers and limited time, with many projects being worked on.

What you need more is probably a dashpot function, which feed the airflow shut as you lift off either through DBW or idle control. Already on the list for when we have time.


I fully understand that, but I do think there is one feature that probably would make a chunk of that list possible in one added feature:

What I'm thinking of is the Generic outputs, now they can only be connected to an output wire, if they also could be assigned as corrections for any channel like throttle, other genOut's, PIDs etc. Or not assigned at all (if all wires are used) and used as a math channel.

This alone would open up a whole new world of custom functions. And add a generic closed loop control on top of that and you can make even more like pit limiter etc.

BR,
Mattias

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Re: Decel Cut - throttle position

Postby HaltechMatthew » Fri Jul 07, 2017 11:10 am

Duly noted and understood. Maybe in future when R&D fill our current list of 1000's of request.

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Mattias
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Re: Decel Cut - throttle position

Postby Mattias » Fri Jul 07, 2017 3:39 pm

HaltechMatthew wrote:Duly noted and understood. Maybe in future when R&D fill our current list of 1000's of request.


Looking forward to it, you need to hire these guys to speed things up ;)
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