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Hello,
I am currently remapping a 1L Ecoboost 3 Cylinders 125hp.
I'm trying to get it as the most simple as possible, by switching off configuration bits for throttle intervention except for torque control.
Therefore, max torque on original setting is set at arround 2.6 bars. I would need more than 3 bars on my torque window, is there any way to tune it above that value even if there are some hard limits in the SW?
Thank you!
you can't switch off torque control on a torque controlled PCM. All power/torque driveability outputs are torque controlled. Also the boost is controlled by torque. there is no boost switch where you can select 2.6 or 3 bar.
Ecoboost engines are difficult and need a lot of knowledge.
Thank you for your reply.
For sure I want to keep it torque controlled. Thing is, if I ask more torque, I would expect my throttle to go WOT, and THEN let the boost increase to reach the target torque. Therefore, it is inverted : the boost go directly to the MAX, and throttle regulates. Is there a way to change that behaviour
Hi,
I only have a few mins so will have to keep this brief...
You need to know that the boost doesnt (or shouldn?t) just go to max and then be throttle regulated at all. In essence the torque request from driver to air delivery process goes along the lines of:
Throttle requested torque at the pedal / various torque limiters trim that down / torque to load provides an air load / air load is double checked with load to torque tables / air load trimmed by every load limiter / air load converted to air mass via speed density slopes /
The air mass is now checked against requested AFR to ensure it can be delivered with the current injector configuration, fuel pressure and allowed timing window. If not, air source becomes fuel limit and the air mass is trimmed to an amount we can fuel for.
That air mass is then converted to air pressure at current speed and conditions via the VE slopes and of course it?s a little different for every cam pair (HFDX) so current cam timing and VCT modes affect the answers.
From there it moves into the air mass delivery system calculating a required turbine speed needed to deliver the requested air mass.
To do that it calculates the current turbine airflow and the required Mass Fraction through the wastegate to achieve the energy needed to deliver that turbine speed. (It?s a heat model essentially
We now pretty much have our ?TIP Desired? which you MUST monitor alongside TIP Actual.
If your boost control is dialled in correctly it will nudge that number and keep close. If you go too high the throttle will close as that?s the fastest possible path to boost control.
It will only close the throttle if we hit too much TIP or air load.
You shouldn?t tune this system with boost as a desired end point really. It should be torque as a desired end point. So if you want it old school you will need to keep reprogram the TTL and LTT tables until the desired torque outputs the manifold pressure you desire.
The ideal from there is to reproduce it properly with your dyno results and the request that actual torque all the way through the torque path so it is properly modelled again.
Also remember, load is not the same as boost.
Thank you mate
I'm used to work on Bosch VAG group ECU's, so all the ecoboosts management are pretty new to me.
I understood all your saying, therefore, I still don't get this point :
I tried to limit the load at 2 through LSPI load maps (and any other limiter out of range for the test), and I can see on a full Load that I have my boost pressure going to 3 bars, whereas my throttle position is still not going WOT (throttle goes arround 50/60%). In all other ECU management I saw so far, the boost starts to raise when the MAP hits the naturally aspirated pressure threshold (throttle wide open). All other interferences will be handled through correct tuning of the fuel, knock, richness, ex. temp, etc.)
Is it possible in Ecoboost strategies to keep the throttle WOT in full load, regardless of any limiters that I will tune properly? I noticed that throttle is closing every time when TIP actual hits TIP desired as you said. Which maps will let the TIP desired going up while limiting the actual TIP to stay below?
Thank you
In a nutshell : Is it possible to control torque or boost through maps that would not affect the TIP desired? For example, I would expect to regulate the torque or boost through the wastegate and not the throttle
Hi,
Yeah, the Bosch strategy is far simpler to understand than Fords own for Ecoboost.
The HDFX system was a VERY steep learning curve to be honest but to be fair, its significantly better in all respects IMO.
For your issue,
Yes, if TIP desired is correct and MAP is lower than MAP limits then the throttle WILL stay open.
I can only assume you are missing a limiter somewhere.
Log "ETC Source" and that will usually tell you why the throttle is closing.
I am "assuming here" that you have checked that yours isnt one of the calibrations that doesnt actually allow WOT below 5000 rpm from the factory. (Look in the ETC section for allowed throttle Vs RPM)
We have some of those strategies on UK cars and they ramp from around 40degrees at 1500rpm to 82 degrees around 5000rpm. Think it was the 1 litre 3 pot Fiesta with the cholcolate engine.
Ref limits, remember you have 3 pressure related limits:
Piston Load (Load)
Manifold Pressure (MAP)
Pre Throttle pressure (TIP)
There are multiple flow limits that can cause a closure so be sure to plot airflow and then look in the aiflow limits areas for any limits you may hit.
(Turbo airflow being a common one)
As an aside...
You should embrace load control via throttle though as its hugely faster than WGDC.
The fastest path is spark as thats per combustion event control, second fastest is throttle. WGDC takes an age by comparson.
Thanks a lot for your answer. I had my Ecoboost to run great, and I can now control torque to target my boost (for the moment 1.8bars on torque, 1.6bars at max power)
Happy to have been able to help.Quote:
Originally Posted by Pro Map Auto
Well done on the tune. It?s satisfying as it all comes together. :)