The first commercially successful automobile, created byKarl Benz, added to the interest in light and powerful engines. The lightweight gasoline internal combustion engine, operating on a four-stroke Otto cycle, has been the most successful for light automobiles, while the thermally more-efficientDiesel engineis used for trucks and buses. However, in recent years,turbochargedDiesel engines have become increasingly popular in automobiles, especially outside of the United States, even for quite small cars.