Longitudinal engine

In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back.

Most "premium" vehicles use this engine orientation, both front and rear wheel driven, due to the fact that powerful engines such as the Inline-6 and 90° big-bore V8 are usually too long to fit in a FF transverse engine while most mainstream modern vehicles use front wheel drive along with transverse engine arrangement

Position placement of longitudinal engines
Engines may be placed in three main positions within the motor car:
 * front engine - where the engine is mounted under the bonnet/hood, over the front axle (sometimes ahead of the front axle, sometimes behind it: "mid-front" engine),
 * rear engine - where the engine is mounted where the boot/trunk would normally be, either over, or to the rear of the rear axle,
 * mid engine - where the engine is mounted between the front and rear axles, usually where the rear seats would be sited.

Common types of longitudinally placed engines
This is a list of typical examples of types of engines which can be placed in motor vehicles:
 * in-line or straight engine - where two, three, four, five, six, and even eight cylinders are placed in a single plane,
 * V engine - where two, four, six, eight, ten, twelve, or even sixteen cylinders are placed in two separate planes, looking like a "V" when viewed from the end of the crankshaft,
 * flat or boxer engine - where two, four, six or more cylinders are arranged in two diametrically horizontally opposed planes,
 * W engine - where two (narrow angle) vee engines are siamesed together (within 180°), where at eight, twelve or sixteen cylinders are arranged in four separate planes,