This one is interesting and not much info available. I have made quite a few assumptions here in the absence of hard data on Toyota's DI system. Do your own verification before using these to tune your engine...
Since DI only has one rev to work with for fuelling rather than a whole cycle: at an 8000 RPM redline, there are 7.5ms per rev rather than 15ms/cycle that the port injectors have to work with.
I looked at a number of relationships betweek DI_IPW and load in log lines with Port_IPW=0 and found the most linear relationship with the commanded fuel vs DI_IPW*FuelPress:
Commanded Fuel fuel g/rev
= Load air g/rev / Commanded_AFR air/fuel
From what I understand, most DI injectors have up to a 5ms pulse width time. Flow is also proportional to fuel pressure. Luckily for us, the peak DI IPW is 5ms and peak DI fuel pressure on the GDI flow table is 20MPa. Multiplying the peak DI (5ms) and peak fuel pressure (20MPa) essentially gives us a 100 % value that we can use directly.
Scripts will be posted in the
MatLab thread.
Figures:
1. Relationship between DI_IPW*FuelPress vs Commanded fuel
2. DI Duty using stock DI system and PI : DI map