 The Elantra PLI is a mild hybrid and the first hybrid to adopt advanced lithium polymer (Li–Poly) batteries.The Elantra LPI Hybrid delivers a fuel economy rating of and CO2 emissions of 99 g/km to qualify as a Super Ultra Low Emission Vehicle (SULEV).The Mercedes-Benz S400 BlueHybrid was unveiled in the 2009 Chicago Auto Show, and sales began in the U.S. in October 2009.