Quiz: Which fuel type is primarily used in diesel engines, and how July 23, 2025 by Alex Turner Which fuel type is primarily used in diesel engines, and how does it differ from gasoline? Discover more about Vehicle Engine and Automobile at our home page. A) Diesel fuel; it is heavier and has a higher energy content than gasoline. B) Ethanol; it is derived from corn and is used to reduce emissions. C) Compressed natural gas; it is cleaner but less energy-dense than diesel. D) Biodiesel; it is produced from vegetable oils and can be used in any engine. Submit Answer