This article relies largely or entirely on a single source .(April 2019)
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 followed, "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."
Most four-wheel-drive layouts are front-engined and are derivatives of earlier front-engine, rear-wheel drive, or front-engine, front-wheel drive designs. The first origins of it were introduced in the 1820s from steam coach builders Burstall & Hill. This was then re-created by many other manufactures, such as “British engineer Joseph Diplock patented a four-wheel-drive system for a traction engine, while in Vienna, Austria, Ferdinand Porsche developed an electric vehicle that also had all wheels driven, with an electric motor at each corner, as early as 1899. This layout is designed for off road vehicles to have the most traction in strenuous situations without losing too much cargo space at the same time.However, the 1903 Spyker 60 HP was the first official car built with an F4 drive layout.
This layout is also the drive train of choice for off-road pickup trucks and SUVs. It allows these vehicles to get the most traction without sacrificing cargo or passenger room. Part-time four-wheel drive vehicles frequently have a transfer case and no center differential, meaning the 4WD mode does not allow any difference in front and rear axle speeds. For normal road driving, these vehicles are shifted into 2WD mode, to prevent damage to the transfer case. Full-time four-wheel drive systems, on the other hand, cannot do without some kind of center differential.The purpose of four-wheel drive is to maintain optimal traction when manually selected. A vehicle has four-wheel drive when the front and rear driveshafts can be locked together to move at the same speed and send the same amount of torque to all four wheels.
A traction control system (TCS), also known as ASR, is typically a secondary function of the electronic stability control (ESC) on production motor vehicles, designed to prevent loss of traction of the driven road wheels. TCS is activated when throttle input and engine power and torque transfer are mismatched to the road surface conditions.
Four-wheel drive, also called 4x4 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.
quattro is the sub-brand used by the car brand Audi to indicate that all-wheel drive (AWD) technologies or systems are used on specific models of its Audi automobiles.
In automotive design, an FF, or front-engine, front-wheel-drive (FWD) 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.
A transfer case is a part of the drivetrain of four-wheel-drive, all-wheel-drive, and other multiple powered axle vehicles. The transfer case transfers power from the transmission to the front and rear axles by means of drive shafts. It also synchronizes the difference between the rotation of the front and rear wheels, and may contain one or more sets of low range gears for off-road use.
4Matic is the marketing name of an all-wheel drive system developed by Mercedes-Benz. It is designed to increase traction in slippery conditions. With the introduction of the 2017 E 63 S sedan, Mercedes-AMG announced a performance-oriented variant of the system called AMG Performance 4MATIC+.
A drive wheel is a wheel of a motor vehicle that transmits force, transforming torque into tractive force from the tires to the road, causing the vehicle to move. The powertrain delivers enough torque to the wheel to overcome stationary forces, resulting in the vehicle moving forwards or backwards.
Torque steer is the unintended influence of engine torque on the steering, especially in front-wheel-drive vehicles. For example, during heavy acceleration, the steering may pull to one side, which may be disturbing to the driver. The effect is manifested either as a tugging sensation in the steering wheel, or a veering of the vehicle from the intended path. Torque steer is directly related to differences in the forces in the contact patches of the left and right drive wheels. The effect becomes more evident when high torques are applied to the drive wheels either because of a high overall reduction ratio between the engine and wheels, high engine torque, or some combination of the two. Torque steer is distinct from steering kickback.
ATTESA is a four-wheel drive system used in some automobiles produced by the Japanese automaker Nissan, including some models under its luxury marque Infiniti.
Jeep uses a variety of four-wheel drive systems on their vehicles. These range from basic part-time systems that require the driver to move a control lever to send power to four wheels, to permanent four-wheel systems that monitor and sense traction needs at all four wheels automatically under all conditions.
Super Handling-All Wheel Drive (SH-AWD) is a full-time, fully automatic, all-wheel drive traction and handling system combining front-rear torque distribution control with independently regulated torque distribution to the left and right rear wheels to freely distribute the optimum amount of torque to all four wheels in accordance with driving conditions." The system was announced in April 2004, and first introduced in the North American market in the second generation 2005 model year Acura RL, and in Japan as the fourth generation Honda Legend.
The layout of a motorised vehicle such as a car is often defined by the location of the engine and drive wheels.
ControlTrac four-wheel drive is the brand name of a selectable automatic full-time four-wheel drive system offered by Ford Motor Company. The four-wheel drive system was designed and developed at BorgWarner under its TorqTransfer Systems division in the mid 1980s. BorgWarner calls the system Torque-On-Demand (TOD). ControlTrac was the first automatic system to use software control and no planetary or bevel geared center differential. Instead of a planetary or bevel geared center differential, the system uses a variable intelligent locking center multi-disc differential.
All Wheel Control (AWC) is the brand name of a four-wheel drive (4WD) system developed by Mitsubishi Motors. The system was first incorporated in the 2001 Lancer Evolution VII. Subsequent developments have led to S-AWC, developed specifically for the new 2007 Lancer Evolution. The system is referred by the company as its unique 4-wheel drive technology umbrella, cultivated through its motor sports activities and long history in rally racing spanning almost half a century.
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.
Torque vectoring is a technology employed in automobile differentials that has the ability to vary the torque to each half-shaft with an electronic system. This method of power transfer has recently become popular in all-wheel drive vehicles. Some newer front-wheel drive vehicles also have a basic torque vectoring differential. As technology in the automotive industry improves, more vehicles are equipped with torque vectoring differentials. This allows for the wheels to grip the road for better launch and handling.
The Jeep Liberty (KJ), or Jeep Cherokee (KJ) outside North America, is a compact SUV that was produced by Jeep from 2002 to 2007. Introduced in May 2001 as a replacement for the Cherokee (XJ), the unibody Liberty was priced between the Wrangler and Grand Cherokee. It was the smallest of the 4-door Jeep SUVs up until the car platform based 4-door Compass and Patriot arrived for 2007.
The drivetrain, also frequently spelled as drive train, or sometimes drive-train, is the group of components of a motor vehicle that deliver power to the driving wheels. This excludes the engine or motor that generates the power. In contrast, the powertrain is considered to include both the engine and/or motor(s), as well as the drivetrain.
An all-wheel drive vehicle is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand.