A four-wheel drive, also called 4×4 or 4WD, is 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.
Overdrive is the operation of an automobile cruising at sustained speed with reduced engine speed (rpm), leading to better fuel consumption, lower noise, and lower wear. The term is ambiguous. The most fundamental meaning is that of an overall gear ratio between engine and wheels, such that the car is over-geared, and cannot reach its potential top speed, i.e. the car could travel faster if it were in a lower gear, with the engine turning at higher RPM.
In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated.
Quattro is the trademark used by the automotive brand Audi to indicate that all-wheel drive (AWD) technologies or systems are used on specific models of its automobiles.
A drive shaft, driveshaft, driving shaft, tailshaft, propeller shaft, or Cardan shaft is a component for transmitting mechanical power, torque, and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them.
The Dodge Power Wagon is a four-wheel drive medium duty truck that was produced in various model series from 1945 to 1980 by Dodge. The Power Wagon name was revived for the 2005 model year as a four-wheel drive version of the Dodge Ram 2500. As a nameplate, "Power Wagon" continues as a special package of the four-wheel drive version of 3/4 ton Ram Trucks 2500 model.
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.
The Jeep Patriot (MK74) is a front-engine five-door compact crossover SUV manufactured and marketed by Jeep, having debuted with the Jeep Compass in April 2006 at the New York Auto Show for the 2007 model year. Both cars, as well as Dodge Caliber shared the GS platform, differentiated by their styling and marketing, with the Patriot exclusively offering a four-wheel drive system, marketed as Freedom Drive II.
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, which combines front-rear torque distribution control with independently regulated torque distribution to the left and right rear wheels. This way the system freely distributes the optimum amount of torque to all four wheels according to the driving conditions. The system was announced in April 2004, and was 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 powertrain layout of a motorised vehicle such as a car is often defined by the location of the engine or motors and the drive wheels.
Super Select is the brand name of a four-wheel drive system produced by Mitsubishi Motors, used worldwide except for North America, where it was initially known as Active-Trac. It was first introduced in 1991 with the then-new second generation of the Mitsubishi Pajero.
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.
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.
A drivetrain or Transmission System, is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components of a motor vehicle that deliver power to the drive wheels. This excludes the engine or motor that generates the power. In marine applications, the drive shaft will drive a propeller, thruster, or waterjet rather than a drive axle, while the actual engine might be similar to an automotive engine. Other machinery, equipment and vehicles may also use a drivetrain to deliver power from the engine(s) to the driven components.
An H-drive drivetrain is a system used for heavy off-road vehicles with 6×6 or 8×8 drive to supply power to each wheel station.
An all-wheel drive vehicle is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand.
The Toyota Sprinter Carib is a front engine, all-wheel drive station wagon produced by Toyota under the Sprinter nameplate from 1982 until 2002. The first generation was based on second generation Tercel and exported as Tercel AWD wagon, while the last two generations were based on Corolla/Sprinter wagons and exported as Corolla wagons.
