Lotus and Renault on Thursday finally announced a new engine deal for 2014 "and beyond".
The Enstone team had already begun winter testing with the French marque's new turbo V6 'power unit', but negotiations between the pair had been long and reportedly difficult.
"The relationship between Viry and Enstone has gone from strength to strength over the past few years," said Renault Sport F1 president Jean-Michel Jalinier.
"This is illustrated in no better way than the excellent – and very close – collaboration on the 2014 car, which is more technically complex than any previous designs."
Book discounted tickets and reservate your hotel room in our F1 Tickets Shop.