Driving by myself with no load at 12:15 in the afternoon with outside temperature at 80 degrees. Vehicle started to make a large screeching sound coming from engine bay. I pulled over into a parking lot and shut off engine. Vehicle continued to make screeching sound from engine bay; I opened hood to a billowing smoke that smelled like an electrical fire. Noise and significant smoke continued for several minutes with engine off and ignition in off position.