Mid-engine design

From Wikipedia, the free encyclopedia

A mid-mounted engine describes the placement of an automobile engine between the centerline of the rear and front axles. Another term for this is Mid-ship, this term is used mostly by Japanese manufacturers.

This layout is typically chosen for its relatively favorable weight distribution - the heaviest component is near the center of the car, making the main component of its moment of inertia relatively low. Heavier objects are harder to deflect in a new direction; on a vehicle the car handling ideal is for neither end to overpower the other with this tendency. Thus a mid-engine design aids in quickly changing the direction of the automobile's travel. Some perceive that a mid-engine design has reduced straight line stability ^{[citation needed]}.

Sports and racing cars typically have a mid-engine design, as the vehicle's handling characteristics are more important than any other feature, such as practicality.

Traditionally, the term mid-engine layout has been applied to cars that place the engine and transaxle behind the driver but in front of the rear axles. This configuration is known as a mid-engine, rear-drive An engine placed in front of the driver's compartment but fully behind the front axle line also meets the definition of a mid-engine.

The largest drawback of mid-engine cars is packaging - most mid-engine vehicles are two seater vehicles. The engine in effect pushes the passenger compartment forward towards the front axle (if engine is behind driver). Exceptions, where the vehicle is practical transportation for more than two people and a small amount of luggage, are rare - typically involving unusual length or the passengers sharing space with the engine - which can be between them or below them.

In the "behind the passenger" design, engine cooling can also be a potential problem, as in the Porsche 914 or Lotus Esprit, but that problem seems to have been largely solved in newer designs such as the Porsche 986. The Saleen S7 appears to also resolve the problem with the use of large engine-compartment vents on the sides and rear of the bodywork.