Just writing to gauge peoples opinions really.

I have seen a few comments about tuning should be aimed so that EOI = 0 degrees or TDC.
Which kind of got me digging and led to where I am now.

With the diesel the power stroke starts with SOI and ends with EOI.
So what we are acutally inerested in IMHO is the duration in crank degrees and how offset it is from TDC.
So I created crank degrees for SOI, Duration and EOI.
I also created a conept I call the MBT ratio.

Normally this refers the best torque and relates to ignition timing and control of the torque with regard TDC.
Spark too early power drives the piston backward.
Spark too late the the mixture is already expanding and the piston on its way down so you lose power.
Spark just right and you get maximum torque at that rpm.
However...for the sake of longevity this igntion is often retarded a little to mimise the crank loads without sacrificing too much power.
I think 8 ATDC is chosen as this point.

Anyway, theres no spark with diesels and you cant burn fuel that isnt there.
Hence the MBT ratio I cam up with.
If duration is the same as SOI....the MBT ratio will be 1:1 (EOI = TDC)
If duration is longer than SOI...the MBT ratio will be less than 1:1 (EOI after TDC)
If duration is shorter than SOI..the MBT ratio will be grater than 1:1 (EOI before TDC)
If Soi starts after TDC..the MBT ratio will be 0 or - values

I applied this to the Honda civic 2.2 iCDTi 2007...and the BMW530d.
Is there a pattern to this ?
Should the MBT ratio be 0 at 0 rpm and then climb in a uniform manner for the same IQ ?

I was thinking this might be a mathematical way to calculate SOI from nothing but duration/IQ
The process is shown from page32 of the pdf onward.

Another example: Opel Astra H cdti 150 hp edc16c9

Do you need EOI?

Thanks....picked up your comment on the other forum.
Very interesting how low IQ is either too late or too early compared ot average..yet hi iq is either too early or too late compared to average.
You would think it would be constantly early or contantly late...compared to average.

I just stumbled across this (a year too late but still). Very interesting topic to myself at the moment as I been looking through SOI maps that are completely different for the same engine - and I am trying to create the "ultimate" SOI map by using information from all the other ones, if that makes sense?

Well the one I pulled off my 206 2.0 HDI as standard has some EOI values that are before TDC. It seems normal to have this on some cars, in some maps, but I have absolutely no idea how it can be in any way beneficial!

I have left the values, I do not want to retard timing and make things worse without understanding the consequences.

Anyway attached is a picture. These EOI values are with a totally stock SOI map.

Tray to play with this: http://www.diesel-rk.bmstu.ru/

You should check out this thread: http://www.ecuconnections.com/forum/vie ... &start=100

Specifically the 5th page. I will be posting a PDF with all my engineering papers based on ignition/injection timing some point this week as well.