Longitudinal engine

A longitudinal engine is an engine mounted in a vehicle so that the engine's crankshaft is parallel with the vehicle, front to back. The majority of rear wheel drive vehicles use a longitudinal engine design. where the engine's crankshaft axis is parallel to the vehicle. Many modern front wheel drive vehicles use a transverse engine mounting design. 
Placement of longitudinal engines.
Engines may be placed in three main positions within the car: