Ferrari said Byrne, who has been working on road car projects as a consultant, would provide "operational support" to the design team.
At the launch of this year's F1 car on 1 February, he told the German magazine Auto Motor und Sport that he was working "full steam ahead" on the 2014 car.
His presence does not change the normal Ferrari design structure and he has no official title.
Ferrari describe him as "an extra pair of hands and eyes, if you like".
Byrne is working as part of a team led by chief designer Nikolas Tombazis under technical director Pat Fry. The co-ordinator of the 2014 car under Tombazis is Italian Fabio Montecchi.
Source:
http://www.bbc.co.uk/sport/0/formula-one/21411177