Renault has promoted company veteran Gaspar Gascon Abellan as its new engineering chief, replacing Jean-Michel Billig.

Renault said in a statement that Billig had left the automaker to work on “personal projects.”

Abellan, a Spanish national, moves to his new job from his current post as head of powertrain engineering. He joined Renault in 1990 and during his career with the company has been in charge of diesel engine projects and powertrain projects.

Billig worked at Eurocopter and Airbus for most of his career. He was appointed Renault’s top engineer in 2012, succeeding Odile Desforges.

In an interview with L’Usine Nouvelle in March, Billig said that he was seeking to improve Renault’s r&d efforts by, among other things, developing Renault’s autonomous driving and car connectivity technologies.

A Renault spokeswoman would not comment on why Billig left the company except to say that he left to pursue personal interests outside of Renault.