Andy Cowell will replace Thomas Fuhr as head of Mercedes' Formula 1 engine arm from the start of 2013.
Fuhr, who has been managing director of Mercedes High Performance Powertrains since 2009, is leaving for a new job outside motorsport.
Cowell is currently the group's engineering director, resposible for Mercedes' current and 2014 F1 engines plus its KERS.
At present, Mercedes supplies engines to McLaren and Force India as well as its factory F1 team.