New cars will soon need 42-volt electrical systems-triple today’s standard-to feed power-hungry electronics like electromechanical engine valves, exhaust treatment systems and active suspensions. MIT researchers say they have removed a key obstacle to this higher-voltage automobile by developing a mass-producible alternator that efficiently and consistently delivers 42-volt power. Starting with a conventional alternator, electrical engineering professor David Perreault added three semiconductor switches that regulate current flow. He also devised a control algorithm for those switches that enables the alternator to deliver 42-volt juice optimally at every engine speed and avoid dangerous power spikes. In recent months, Perreault’s team cleared a final hurdle by making the bench-top device deliver enough power when the engine is idling. The payoff: Perreault says that three major auto-parts makers have licensed the technology for product development.