I'm a new owner of a 2013 Titanium Energi. I don't notice it when I'm in the car, but if I'm outside of the car and my wife or daughter starts the car and backs out of the driveway and the begins to drive away, there is a noise in the engine compartment. It's hard to describe, but it sounds similar to a drill running The car is fully charged and in EV mode. Is this normal? The car performs fine. Thanks in advance for your comments.