Volkswagen AG is expected to appoint Matthias Mueller, the head of its Porsche sports car division, as its new CEO, replacing Martin Winterkorn, the executive ousted in the wake of a scandal over the rigging of U.S. diesel emissions tests. The 62-year-old Mueller will be formally named tomorrow during a meeting of VW’s supervisory board. He will have to oversee what has become the biggest crisis in the history of what this year became the world’s largest automaker.