FRANKFURT -- Porsche said its development chief, Wolfgang Hatz, has left the company "at his own request" following months of his suspension amid parent Volkswagen Group's emissions scandal.
Hatz, 57, was VW Group's powertrains chief during the time that the automaker developed and sold diesel engines manipulated to cheat tests for health-harming NOx emissions.
Michael Steiner, 51, will succeed Hatz immediately, Porsche said in a statement today. Steiner is currently head of quality management.
Hatz was placed on temporary leave in late September when the emissions-rigging became public and after VW Group appointed U.S. law firm Jones Day to investigate the scandal.
Since then, Hatz has been involved in the investigation "though enquiries have shown no evidence of any co-responsibility by Hatz so far," Porsche said. "Nevertheless he has decided to leave Porsche AG due to the ongoing internal investigations and his resulting prolonged leave of absence," the company said.
Hatz is regarded as one of the German auto industry's best engineers and Porsche had resisted pressure to push him out, instead preferring to operate without one of its senior executives in the hope that he might be able to return.
When VW Group said in April that it would not publish the preliminary findings of its external investigation by Jones Day by the end of last month as planned, it meant that any possible role Hatz may have played in the scandal would not have been clarified with certainty any time soon.
Hatz became responsible for VW Group powertrain development in 2007 but gave up the post in 2012 to focus on his Porsche r&d job he took on in 2011.
Hatz joins three other top VW Group executives who have left the automaker since the diesel scandal broke -- VW Group CEO Martin Winterkorn, Audi’s former development chief Ulrich Hackenberg and ex-VW powertrain boss Hans-Jakob Neusser.
Hatz's career included stints as a BMW engine development project leader, Opel's motorsport technical director and head of engines and transmissions at Fiat.
His successor, Steiner, a former Daimler executive, was head of the Porsche Panamera development project.