In automotive design, a front-mid-engine, front-wheel-drive layout (also called more simply "mid-engine, front-wheel-drive layout", and abbreviated MF or FMF) is one in which the front road wheels are driven by an internal-combustion engine placed just behind them, in front of the passenger compartment. [1] [2] [3] [4]
In contrast to the front-engine, front-wheel-drive layout (FF), the center of mass of the engine is behind the front axle. This layout is typically chosen for its better weight distribution (the heaviest component is near the center of the car, lowering its moment of inertia). Many early successful (and mostly French) mass-produced front-wheel drive cars used the MF layout, until the 1959 BMC (Austin / Morris) Mini demonstrated the layout and passenger car packaging benefits of mounting the engine transversely in front of the front axle. At first – when well executed – the packaging, space utilization and user experience of MF layout, even in a subcompact or supermini, like the Renault 16 or Renault 5, made many people consider the differences between the FF and MF layouts to be minor.
However, the mid-engined layout uses central space. The FF layout has since completely supplanted the MF layout, and almost all manufacturers currently fit transverse engines.
Examples of road cars using the MF layout include the Cord 810, BSA Scout, Citroën Traction Avant, Citroën DS, Renault 4 (and derivatives R5 and R6), Renault 16, Saab 900 Saab Sonett mk1, and the Citroën SM, also some commercial vehicles like the Tempo Matador. These vehicles have longitudinal mounted engines; transverse engined vehicles are possible in theory if the issue of passenger footwell location is addressed. The Toyota iQ comes close to this by having its front differential in front of the engine, [5] however despite this, the iQ is still considered to have an FF layout.
Traditionally, the term mid-engine has been reserved for cars that place the engine and transaxle behind the driver and in front of the rear axles [ citation needed ], as in the Lamborghini Countach or Ferrari Testarossa, but an engine placed in front of the driver's compartment but fully behind the front axle line also qualifies as mid-engine.
A hatchback is a car body configuration with a rear door that swings upward to provide access to the main interior of the car as a cargo area rather than just to a separated trunk. Hatchbacks may feature fold-down second-row seating, where the interior can be reconfigured to prioritize passenger or cargo volume.
A torsion bar suspension, also known as a torsion spring suspension, is any vehicle suspension that uses a torsion bar as its main weight-bearing spring. One end of a long metal bar is attached firmly to the vehicle chassis; the opposite end terminates in a lever, the torsion key, mounted perpendicular to the bar, that is attached to a suspension arm, a spindle, or the axle. Vertical motion of the wheel causes the bar to twist around its axis and is resisted by the bar's torsion resistance. The effective spring rate of the bar is determined by its length, cross section, shape, material, and manufacturing process.
Four-wheel drive, also called 4×4 or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case providing an additional output drive shaft and, in many instances, additional gear ranges.
Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel-drive and four-wheel-drive vehicles.
In automotive design, a front-engine, front-wheel-drive (FWD) layout, or FF layout, places both the internal combustion engine and driven roadwheels at the front of the vehicle.
In automotive design, an RR, or rear-engine, rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the rear axle and the rear bumper. Although very common in transit buses and coaches due to the elimination of the drive shaft with low-floor buses, this layout has become increasingly rare in passenger cars.
In automotive design, an RMR, or rear mid-engine, rear-wheel-drive layout is one in which the rear wheels are driven by an engine placed with its center of gravity in front of the rear axle, and thus right behind the passenger compartment. Nowadays more frequently called 'RMR', to acknowledge that certain sporty or performance focused front-engined cars are also "mid-engined", by having the main engine mass behind the front axle, RMR layout cars were previously just called MR, or mid-engine, rear-wheel-drive layout), because the nuance between distinctly front-engined vs. front mid-engined cars often remained undiscussed.
Economy car is a term mostly used in the United States for cars designed for low-cost purchase and operation. Typical economy cars are small, lightweight, and inexpensive to both produce and purchase. Stringent design constraints generally force economy car manufacturers to be inventive. Many innovations in automobile design were originally developed for economy cars, such as the Ford Model T and the Austin Mini.
Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-wheel drive vehicles feature a longitudinally-mounted engine at the front of the car.
A transaxle is a single mechanical device which combines the functions of an automobile's transmission, axle, and differential into one integrated assembly. It can be produced in both manual and automatic versions.
In automotive engineering, a mid-engine layout describes the placement of an automobile engine in front of the rear-wheel axles, but behind the front axle.
Torsen Torque-Sensing is a type of limited-slip differential used in automobiles.
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the direction of travel. Many modern front-wheel drive vehicles use this engine mounting configuration. Most rear-wheel drive vehicles use a longitudinal engine configuration, where the engine's crankshaft axis is parallel with the direction of travel, except for some rear-mid engine vehicles, which use a transverse engine and transaxle mounted in the rear instead of the front. Despite typically being used in light vehicles, it is not restricted to such designs and has also been used on armoured fighting vehicles to save interior space.
The configuration of a car body is typically determined by the layout of the engine, passenger and luggage compartments, which can be shared or separately articulated. A key design feature is the car's roof-supporting pillars, designated from front to rear of the car as A-pillar, B-pillar, C-pillar and D-pillar.
The powertrain layout of a motorised vehicle such as a car is often defined by the location of the engine and drive wheels.
A vehicle frame, also historically known as its chassis, is the main supporting structure of a motor vehicle to which all other components are attached, comparable to the skeleton of an organism.
In automotive design, an F4, or front-engine, four-wheel drive (4WD) layout places the internal combustion engine at the front of the vehicle and drives all four roadwheels. This layout is typically chosen for better control on many surfaces, and is an important part of rally racing, as well as off-road driving. In terms of racing purposes, whether it be on-road or off-road, can be described as follows,
A team that pursues the Weak LS4WD architecture will minimize the development cost of the front-wheel drive system at the expense of having a larger rear powertrain. The Weak architecture produces a vehicle with a large powersplit between the front and rear powertrains, while the Strong architecture recommends a vehicle with more similar power and torque requirements for the front and rear.
In automotive design, an M4, or Mid-engine, Four-wheel-drive layout places the internal combustion engine in the middle of the vehicle, between both axles and drives all four road wheels.
France was a pioneer in the automotive industry and is the 11th-largest automobile manufacturer in the world by 2015 unit production and the third-largest in Europe. It had consistently been the 4th-largest from the end of World War II up to 2000. It is 16 % of sales of French manufactured products.
The Citroën Traction Avant is the world’s first unibody front-wheel-drive car. A range of mostly 4-door saloons and executive cars, were made with four or six-cylinder engines, produced by the French manufacturer Citroën from 1934 to 1957. Approximately 760,000 units were produced.