Originally Posted by Commander Keen
You can use a number of unit types for BSFC:
-Energy over time vs power (GPH per HP)
-Energy vs power over time (Gal per HP hour)
HP and Kw describe power.
HP/hour and Kwh describe work.
Work is power over time.
The joule is a unit of work, so it doesn't need the /time conversion like the others. All forms are valid.
True, and it basically means the ratio of joules out over joules in (or whatever unit of energy, or work, you want to use. Whenever time is in the equation it's in there somewhere else to cancel out.