We pulled off the highway to get gas and noticed smoke coming from the hood. We immediately parked at the gas station and my husband, our dog and I got out of the car and within minutes the entire front of the car was in flames. Several passersby stopped and sprayed the fire with their fire extinguishers. We called 911 and the fire department quickly arrived and put out the fire, but the entire front of the car was destroyed. The front of the car melted along with the windshield from the intense heat. The police inspector came and inspected the car and took photos. The car was then towed and our insurance company took possession of the car. There were no warning lights or messages prior to the failure. The only thing we noticed was a slight hesitation in power as we climbed a hill several times in the half hour preceding the failure. My husband, my dog and I would have been in mortal danger from the fire if we had not stopped immediately and gotten out of the car. The safety of other people nearby had also been at risk if the fire department had not arrived so quickly to put out the fire as the smoke began as we were entering the gas station and parked about 50 feet from the gas pumps to escape the vehicle. We have no idea what caused the fire. The engine had been replaced by Hyundai due to a defect that had caused it to fail about 2 years prior to the current failure.