So the only injector delay or lag I can find in ME9 FR is implimented via the map KLTVTSV. This map takes only one input parameter which is the pressure difference between the rail and the combustion chamber, and outputs a delay in milliseconds.

The table has an interesting form to it in my ME9.1 file. It starts off with a very small negative value for the largest differences in pressures, and tapers to a very small positive value for the smallest differences in pressures. For my file it runs from -0.05 up to 0.04, and the axis is supposed to be MPa, but my values run from 14.48 MPa down to 1.87 MPa.

So the question for those that understand this table's influence, how to I adjust to compensate for the increased injector lag of larger (RS4) injectors? What are the typical values one would expect to use. I have read that there is an B7 RS4 file around here with this defined in it, but for the life of me I cannot find it.

Any help understanding this is appreciated.

EPY

Will take a look tonight!

Well I started trying to compare and define the fuel angle maps, and I think I am close, but the axis look bad. Anybody want to take a look?

epy

Thank you. That is definitely about the topic, but I probably didn't state my confusion about this item very well. What I don't understand is what positive and negative numbers in this map mean, and what magnitude the numbers should be.

In particular, the values are on the order of 0.05, but lag for injectors is usually 10x larger than that (say 0.5 - 1.0 ms). So if this is truly a lag value, why is it so small?

Also, what negative and positive values? They should be all one sign, or this indicates that an injector can become predictive and actually start to fire before it gets a signal? I mean how else would the lag be negative? Or conversely, if negative values indicate lag before action, then how would it also be positive which would again imply the injector is firing before getting a signal to?

I understand that there are 2 parts to the time for injection to take place:
1. time for the solenoid to open the injector
2. time for the fluid to flow from the seat to the holes

Greater pressure will make the flow from the seat to the holes faster once flow is established, but the time to open the injector should be similar.

For the first item, a shorter injection time lag could make sense for the values if we were talking a difference between a gas solenoid injector vs. a diesel piezo, then I could understand maybe a DI injector lag being 10x less in the piezo than a solenoid port injector. But both the port and DI injectors use solenoid technology, so that seems odd (at least to me) that the solenoid in a DI injector opens that much faster. I am not saying this is wrong, but do we have any papers, publications, or other reference on this?

Over the last 2 days I tried changing the values of the positive numbers by a factor of 2 and 10, and both times it started the same in cold conditions. ?

epy

MED9 doesn't have TVUB, but does have a map that is "kinda" similar, and it is identified in the FR as for injector lag. This is the KLTVTSV map.

However, all the threads on the RS4 injectors don't provide any info beyond "go read the FR" or "you need to adjust angle and lag, now go read the FR". The only other thing ever mentioned was "the info of what needs to be changed is in the RS4 damos, so go read that FR and look at the RS4 damos". But nowhere is it indicated where the damos or map locations in either the MED9.1 file for the 2.0 or 4.2. So I am trying to get threads started that will actually give that info. As a start, I was hoping to get a 4.2 file with the lag map defined, and then also the 2.0 file with the lag map defined. That is what this thread is for. Next I would like to start looking at the angle maps.

Now if you do go read the FR, you see that AWEA has the einspritzen angle and lag maps, and I did track down potential maps locations for these and the kp is posted above. The values in the angle maps look OK to me (300-400 degrees crank angles), but the lag map makes no sense to me.

epy

Well we have limited pro league support, because Taylor was kind enough to confirm the KLTVTSV map address, correct my definition of the axis address, and also provide some insight. The map I had tracked down in the file had the wrong axis address, and that made it more confusing, so correcting it helps a lot. Also, Taylor confirmed that this map does indeed have negative and positive values by looking at other files he has defined. I will post up the new map kp file at lunch.

The interesting thing is I am working on the new RS4 multi-hole injector, so there are additional considerations I am making that may or may not apply to the older single hole RS4. But the approach for tuning for them is still the same. Here is an interesting article that hints at some potential differences.

The first one that I need to solve is a hardware issue. The new multi-hole injectors operate on a 65 Volt booster signal, but I do not know if the MED9 ECU does this or not (it is discussed in the two articles below for the Delphi injector and the Bosch ECU).  Does anybody know what booster voltage the single-hole FSI fuel injectors work at (i.e., MED9)?

http://www.delphi.com/docs/default-source/sae-technical-papers/2014/Fuel-System-Pressure-Increase-for-Enhanced-Performance-of-GDi-Multi-Hole-Injection-Systems-pdf.pdf?sfvrsn=0
http://www.bosch-motorsport.com/media/catalog_resources/Manual_HPI5_2012_02pdf.pdf

I didn't even know they had a new design version! that's good info