The engine is typically placed in one of three
locations. In the vast majority of vehicles, it is located as the front
of the vehicle, in front of the passenger compartment. Front-mounted
engines can be positioned either longitudinally or transversely with
respect to the vehicle.
The second engine location is a mid-mount position
between the passenger compartment and rear suspension. Mid-mount engines
are normally transversely mounted. The third, and least common, engine
location ins the rear of the vehicle. The engines are typically
Each of these engine locations offers advantages and
Front Engine Longitudinal.
In this type of vehicle, the engine, transmission,
front suspension, and steering equipment are installed in the front of
the body, and the differential and rear suspension are installed in the
rear of the body. Most front engine longitudinal vehicles are rear-wheel
drive. Some front-wheel-drive cars with a transaxle have this
configuration, and most four-wheel-drive vehicles are equipped with a
transfer case and have the engine mounted longitudinally in the front of
Total vehicle weight can be evenly distributed
between the front and rear wheels with this configuration. This lightens
the steering force and equalizes the braking load. With this design, it
is possible to independently remove and install the engine, propeller
shaft, differential, and suspension. Longitudinally mounted engines
require large engine compartments. The need for a rear-drive propeller
shaft and differential also cuts down passenger compartment space.
Front Engine Transverse.
Front engines that are mounted transversely sit
sideways in the engine compartment. They are used with transaxles that
combine transmission and differential gearing into a single compact
housing, fastened directly to the engine. Transversely mounted engines
reduce the size of the engine compartment and overall vehicle weight.
Transversely mounted front engines allow for
down-sized, lighter vehicles with increased interior space. However most
of the vehicle weight is toward the front of the vehicle. This provides
for increased traction by the drive wheels. The weight also places a
greater load on the front suspension and brakes.
In this design, the engine and drivetrain are positioned between the
passenger compartment and rear axle. Mid-engine location in used in
smaller, rear-wheel-drive, high-performance sports cars for several
reasons. The central location of heavy components results in a center of
gravity very near the center of the vehicle. This vastly improves
steering and handling. Since the engine is not under the hood, the hood
can be sloped downward, improving aerodynamics and increasing the
driver's field of vision. However, engine access and cooling efficiency
are reduced. A barrier is also needed to reduce the transfer of noise,
heat, and vibration to the passenger compartment.