Diesel fuel consist of hydrocarbons of a chain length between eight (8) and twenty-one (21) carbon atoms, and has higher energy content per volume than gasoline. Because the hydrocarbons in diesel are larger, it is less volatile and therefore less prone to explosion, which is one reason it is preferred in military vehicles.
Unlike gasoline engines, diesel engines do not rely upon electrically generated sparks to ignite the fuel. Diesel is compressed to high degree along with air, creating high temperatures within the cylinder that lead to combustion. This process position diesel engines highly efficient, achieving up to 40% better fuel economy than gasoline powered vehicles.
Until recently, diesel fuel contained a high degree of sulphur, which contributes to acidic rain. Because of their similar distillation points, diesel and sulfur contaminants are removed from crude at the same time during refining. Government regulation now requires that additional steps be taken to remove the sulfur content so that diesel fuel is more environmentally friendly, which has attributed to the high prices of diesel as compared to gasoline.