[benj111]

Its less refined in the sense of less cracking.

It contains more energy for a given volume, so you get better fuel economy than with petrol. It might not be better for the particulates and NOx that we are now optimising for, but its better for CO2, that we were optimising for. So I don't think the snake oil label is warranted.

[lscotte]

Diesel engines are also significantly more efficient at converting that energy into usable torque. That's why an idling diesel consumes almost no fuel - it isn't doing any work.