[Arragonis]

Diesels have no throttle as they are fuel controlled - more fuel, more powah.

They need compression to ignite the fuel - higher compression means air heats up to super temps and fuel ignites as it is injected.

In older engines the injection took place in one go from a mechanical pump. In more modern engines injection takes place over lots of phases - a little bit at the start to heat things up, the power bit (depending on pedal position, engine speed etc.), and then a little bit later on to deal with anything left over - to reduce emissions.

The timing and volume of these depends, as I tapped and as I understand it, on loads of variables (the map) - engine temp, engine speed, pedal position, turbo boost, fuel quality, zodiac position - all sorts.

But I think lugging is basically when the engine makes less on the power stroke than is needed to maintain rotation speed.

Maybe I have this wrong.