A litre engine is an internal combustion engine with a displacement, or capacity, of one liter. This means that the total volume of the cylinders in the engine is equal to one cubic liter (approximately 61 cubic inches). The term "litre" refers to the metric unit used to measure engine displacement, while "engine" refers to a machine designed to convert fuel into mechanical energy through combustion. In other words, a litre engine has an engine capacity of one liter or approximately 30.5 cu in (497 cc) and is commonly found in small cars, motorcycles, and scooters.