Tokunaga, who has been with the team since 2000, will become the French manufacturer's Technical Director in charge of the development of the new smaller, turbocharged engines that will be introduced into Formula 1 in 2014.

Lotus say he leaves the team with their "full blessing" and that his old role will "remain vacant for the foreseeable future".

The team's Technical Director James Allison said: "While we are sad on a personal level to see Naoki leave Enstone, we believe this move will be overall positive for Renault Sport F1's customers.

"We would like to thank Naoki for the tremendous contribution he has made to our team during the 12 years he has been with us and we look forward to the performance he will bring us (and all of Renault Sport F1's client teams) in his new role."

Lotus, the former Renault-owned outfit, is now one of four customer engine teams on the French firm's books, Red Bull, Williams and Caterham being the others.