If anyone's interested having this for reference, here's my measurements:
Engine: OM617.910
Idle (warm engine): 0.0183L/minute (1.098L/hour)
About 20% throttle (warm engine): 0.0396L/min (2.374L/H)
Both measurements are 10-minute averages.
I would like to get the full-throttle consumption but with no load it isn't possible, and driving around with a jar of diesel between my knees wasn't an option..
IF the injection throttle increase is linear a full throttle application would give something like 12L/hour but I find that a bit on the low side so I don't think I can extrapolate the 20%-figure onto a credible 100%-value.