In-line engine, generally abbreviated as L, such as L4 means the inline 4 cylinder.
The in-line layout is the most widely used cylinder arrangement today, especially on engines with displacements below 2.5L. All the cylinders of the engine of this layout are arranged side by side at the same angle, and only one cylinder head is used, and the structure of the cylinder and the crankshaft is relatively simple, just like the cylinders stand in a column.
Specifically, we generally have four types of L3, L4, L5, and L6 (the number represents the number of cylinders). The advantages of this layout engine are compact size, high stability, low speed torque characteristics and low fuel consumption, which of course means lower manufacturing costs. At the same time, the engine with in-line cylinder layout is also compact, allowing for a more flexible layout. It is also convenient to arrange a supercharger type device. However, its main disadvantage is that the engine itself has low power and is not suitable for vehicles with more than 6 cylinders.