Some of the science behind oil lubcication that is common in engines can be read here:
https://en.wikipedia.org/wiki/Fluid_bearing
Note though, that not all engine components are necessarily lubricated hydrodynamically.
I'm sure you've seen some links to this already, but if you haven't, this site/forum has a wealth of oil info:
http://www.bobistheoilguy.com/motor-oil-101/