Enclosure for fuel entered by Rolls-Royce (6)
I believe the answer is:
'enclosure' is the definition.
(I know that corral is a type of pen)
'fuel entered by rolls-royce' is the wordplay.
'fuel' becomes 'coal' (coal is a kind of fuel).
'entered by' means one lot of letters goes inside another (I've seen this in other clues).
'rolls royce' becomes 'rr' (short for Rolls Royce).
'coal' enclosing 'rr' is 'CORRAL'.
'for' acts as a link.
(Other definitions for corral that I've seen before include "Pen for cattle - ring of waggons" , "Round up" , "American enclosure for horses" , "An enclosure for horses or cattle" , "Livestock enclosure" .)