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Encyclopedia > Front wheel drive

Front wheel drive is the most common form of engine/transmission layout used in modern passenger cars, where the engine drives the front wheels. Most front wheel drive vehicles today feature transverse engine mounting, though many in prior decades were positioned longitudinally instead. Rear wheel drive was the traditional standard while four wheel drive is also sometimes used. See also FF layout. An engine is something that produces some effect from a given input. ... In mechanics, a transmission or gearbox is the gear and/or hydraulic system that transmits mechanical power from a prime mover (which can be an engine or electric motor), to some form of useful output device. ... Restored passenger cars on display at the Mid-Continent Railway Museum in North Freedom, WI. A passenger car is a piece of railroad rolling stock that is designed to carry passengers. ... A driving wheel on a steam locomotive. ... A transverse engine is an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle. ... In automotive engineering, a longitudinal engine, also sometimes known as a north-south engine, is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back. ... Rear wheel drive was a common form of engine/transmission layout used in automobiles throughout the 20th century. ... Four wheel drive or 4x4, is a type of four wheeled vehicle drivetrain configuration that enables all four wheels to receive power from the engine simultaneously in order to provide maximum traction. ... In automobile design, an FF, or Front-engine, Front wheel drive, layout places both the engine and driven wheels at the front of the vehicle. ...

Contents


History

Experiments with front wheel drive cars date to the early days of the automobile. Alvis Cars of the United Kingdom introduced a front wheel drive model in 1928, but it was not a success. The first successful models were the 1934 Traction Avant cars from Citroën in Europe, and the contemporary 810 from Cord Automobile in the United States. The Alvis Silver Eagle mascot. ... 1928 (MCMXXVIII) was a leap year starting on Sunday (link will take you to calendar). ... 1934 (MCMXXXIV) was a common year starting on Monday (link will take you to calendar). ... The Citroën Traction Avant was a automobile produced by the French manufacturer Citroën from 1935 to 1957. ... Citroën is a French automobile manufacturer, started in 1919 by André Citroën, today part of PSA Peugeot Citroën. ... A 1929 Cord L-29 Phaeton on display at the 2005 United States Grand Prix Cord L-29. ...


Front wheel drive was further advanced by the now-legendary Mini of 1959 (even if Saab 92 predates it) although its mechanical layout differed from modern vehicles, since the transmission was built into the sump of the engine, and drive was transferred to it via a set of primary gears. This concept was also used by Peugeot and Renault on their jointly-developed "Douvrin" engine of the 1970s. The tendency of this layout to generate unwanted gearbox "whine" has seen it fall out of favour, except at Saab. The first-generation Saab 900 had this layout with helical gears but the thrust bearings involved gave out a characteristic "zing" sound almost like a hairdryer. The Mini (from Latin small) is the name of a small car produced by the British Motor Corporation (BMC) and its successors from 1959 to 2000, and the name of its replacement (known as the New MINI) launched in 2001. ... 1959 (MCMLIX) was a common year starting on Thursday of the Gregorian calendar. ... Saab 92 Saab 92 is an automobile from Saab. ... A sump is a low area that collects an often-undesirable liquid(s) such as water or chemicals. ... Spur gears found on a piece of farm equipment. ... Peugeot is a major French car brand which is today part of PSA Peugeot Citroën. ... Renault S.A. is a French vehicle manufacturer producing small to upper-midsize cars, vans, buses and trucks. ... The Douvrin family was an all-aluminum straight-4 automobile engine made in a joint-venture between Peugeot and Renault in the 1970s. ... Categories: Stub | Hairdressing ...


Audi pioneered the "U-Drive" layout where the engine is mounted longitudinally, in an "overhung" position over the front wheels. Audi is one of the few manufacturers which still uses this particular configuration. It allows the use of equal-length half shafts and the easy addition of all wheel drive. Audi is an automobile maker in Germany, and is a wholly-owned subsidiary of the Volkswagen Group. ... Manufacturing is the transformation of raw materials into finished goods for sale, or intermediate processes involving the production or finishing of semi-manufactures. ... A half shaft is an automotive term used to describe a driveshaft that goes from a vehicles differential to one of the driven wheels. ... Four wheel drive or 4x4, is a type of four wheeled vehicle drivetrain configuration that enables all four wheels to receive power from the engine simultaneously in order to provide maximum traction. ...


All Subaru front wheel drive and all wheel drive layouts are derived from the standard longitudinal front engine/rear drive transmission configuration, however the differential for the front wheels is between the bellhousing and the gearbox. Visually, the front CV axles come out of the sides of the bellhousing, directly behind the clutch/torque converter area. The engine sits entirely in front of the front axle centerline, however, the short fore-aft length of the boxer engine allows this configuration without any weight distribution issues. Subaru (In katakana: スバル), a Japanese car company, is a subsidiary of Fuji Heavy Industries (FHI). ...


The Oldsmobile Toronado, which reintroduced front-drive to the U.S. market in 1966, also used a longitudinal engine placement for its V-8, coupled with an unusual "split" transmission, which turned the engine power 90 degrees. The driveline was set well behind the centerpoint of the wheels, however, for better weight distribution. (Consequently, it was sometimes called the Mafia car, because it was "all hood"). The Toronado was produced by the Oldsmobile Division of General Motors from 1966 to 1992. ...


The Cadillac Eldorado, with front wheel drive introduced in 1967, holds the record for the largest engine in a front wheel drive production vehicle, at 8.2 liters (The 1970 edition). The Cadillac Eldorado continued to be the only front wheel drive offering from Cadillac until 1980, when the front wheel drive Cadillac Seville was introduced. Reasons cited for the enormous engine are smoothness due to the inertia of the engine soaking up much of the vibration caused by low milling tolerances of the era, resulting in a very smooth ride. To meet Wikipedias quality standards, this article or section may require cleanup. ... Wikimedia Commons has more media related to: Cadillac Seville The Seville, introduced in 1975, was Cadillacs answer to the fuel crunch of the early 1970s, and the rising popularity of luxury imports in the USA from Europe, such as Mercedes-Benz and BMW. At one time, Cadillac toyed with...


Acceleration-wise, the Dodge SRT-4 (2003-2005) holds the world record for the quickest and fastest front wheel drive production vehicle. To meet Wikipedias quality standards, this article or section may require cleanup. ...


The changeover of cars in the US to front wheel drive began in earnest in the 1980s, with the introduction of the compact Chevrolet Citation probably marking the real beginning, and the 1986 introduction of the Ford Taurus bringing front wheel drive to prominence in mid-size cars. By the mid 1980s most formerly rear wheel drive Japanese models were front wheel drive, and by the mid 1990s most American brands only sold a handful of rear wheel drive models. Some suggest that the introduction of the Volkswagen Rabbit in 1974 led to Detroit's Big Three to market the FF layout; Chrysler's vehicle lineup was 100% FF by decade's end. GM followed Chrysler in the mid-1990s when their vehicle lineup was FF (with the exception of the Corvette and F-body lineup). The 1980s decade refers to the years from 1980 to 1989, inclusive. ... The Chevrolet Citation was a compact car sold by General Motors Chevrolet brand from 1980 through 1985. ... The Ford Taurus (from Latin bull) is a midsize car sold by the Ford Motor Company in North America. ... The Volkswagen Golf is an automobile manufactured by Volkswagen. ...


The vast majority of front wheel drive vehicles today use the transversely mounted engine with "end-on" mounted transmission, driving the front wheels via driveshafts linked via Constant Velocity (CV) joints. This configuration was made popular by the Fiat 128 of 1969. The 1959 Mini, while a pioneering transverse front wheel drive vehicle (although later then the 1949 Saab 92), used a substantially different arrangement with the transmission in the sump of the engine. A transverse engine is an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle. ... Cross-section through a typical outer CV joint (Saab 96) Constant Velocity Joints or homokinetic or CV joints allow a rotating shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. ... The 128 was a subcompact automobile manufactured by the Italian manufacturer Fiat from 1969 to 1985. ... 1969 (MCMLXIX) was a common year starting on Wednesday For other uses, see Number 1969. ... 1959 (MCMLIX) was a common year starting on Thursday of the Gregorian calendar. ... The Mini (from Latin small) is the name of a small car produced by the British Motor Corporation (BMC) and its successors from 1959 to 2000, and the name of its replacement (known as the New MINI) launched in 2001. ... 1949 (MCMXLIX) is a common year starting on Saturday. ... Saab 92 Saab 92 is an automobile from Saab. ...


It is also of note that many American auto manufacturers are shifting many of their more expensive models away from Front Wheel Drive. Chrysler's 300, and almost the entirety of the Cadillac lineup are some examples of cars that have, previous to the last five years, been offered only in front wheel drive form.


Advantages of front wheel drive

  • Packaging efficiency: the powertrain is a single unit contained in the engine compartment of the vehicle, obviating the need to devote interior space for a driveshaft tunnel or rear differential and increasing the volume available for passengers and cargo.
  • Cost: Fewer components overall.
  • Improved drivetrain efficiency: the direct connection between engine and transaxle reduce the mass and mechanical inertia of the drivetrain compared to a rear-wheel drive vehicle with a similar engine and transmission, allowing greater fuel economy.
  • Assembly efficiency: the powertrain can be often be assembled and installed as a unit, which allows more efficient production.
  • Slippery-surface traction: placing the mass of the drivetrain over the driven wheels improves traction on wet, snowy, or icy surfaces.
  • Predictable handling characteristics: front-wheel drive cars, with a front weight bias, tend to understeer at the limit, which is commonly believed to be easier for average drivers to correct than terminal oversteer, and less prone to result in fishtailing or a spin.

Powertrains, in the automobile world, consist of all the components of a vehicles drive system. ... Cardan driveshaft with universal joints A driveshaft or driving shaft or Cardan shaft is a mechanical device for transferring power from the engine or motor to the point where useful work is applied. ... A differential can mean one of several things: Differential (mathematics) Differential (mechanics) Differential signaling is used to carry high speed digital signals. ... The principle of inertia is one of the fundamental laws of classical physics used to describe the normal motion of matter, and how it is affected by applied forces. ... Rear wheel drive was a common form of engine/transmission layout used in automobiles throughout the 20th century. ... Fuel efficiency, sometimes also referred to as fuel economy and commonly gas mileage in the United States, is a numeric measure often used to describe the amount of fuel consumed with regard to the distance travelled in a transportation vehicle, such as an automobile. ... Traction is applied mechanical force used to achieve motion. ... Understeer is a term for a car handling condition during cornering in which the circular path of the vehicles motion is of a greater diameter than the circle indicated by the direction its wheels are pointed. ... Oversteer, in an automobile, occurs when the rear tires have a loss of traction during a cornering situation, thus causing the rear of the car to head towards the outside of the corner. ... Fishtailing is a problem with rear wheel drive vehicles. ...

Disadvantages of front wheel drive

  • The center of gravity of the vehicle is typically further forward than a comparable rear-wheel drive layout. In front wheel drive cars, the front axle typically supports around 2/3rd of the weight of the car (quite far off the "ideal" 50/50 weight distribution). This is a contributing factor towards the tendency of front wheel drive cars to understeer.
  • Torque steer can be a problem on front wheel drive cars with higher torque motors( > 210 Nm ). This is the name given to the tendency for some front wheel drive cars to pull to the left or right under hard acceleration. It is a result of the offset between the point about which the wheel steers (which falls at a point which is aligned with the points at which the wheel is connected to the steering mechanisms) and the centroid of its contact patch. The tractive force acts through the centroid of the contact patch, and the offset of the steering point means that a turning moment about the axis of steering is generated. In an ideal situation, the left and right wheels would generate equal and opposite moments, cancelling each other out, however in reality this is less likely to happen. Torque Steer is often incorrectly attributed to differing rates of twist along the lengths of unequal front drive shafts.
  • Lack of Weight Shifting will limit the acceleration of a front wheel drive vehicle. In a rear wheel drive car the weight shifts back during acceleration giving more traction to the driving wheels. The fact that this does not happen in a front wheel car is the main reason why nearly all racing cars are rear wheel drive. However, since front wheel cars have the weight of the engine over the driving wheels the problem only applies in extreme conditions.
  • In some towing situations front wheel drive cars can be at a traction disadvantage since there will be less weight on the driving wheels. Because of this, the weight that the vehicle is rated to safely tow is likely to be less than that of a rear wheel drive or four wheel drive vehicle of the same size and power.
  • Due to geometry and packaging constraints, the CV joints (constant-velocity joints) attached to the wheel hub have a tendency to wear out much earlier than their rear wheel drive counterparts. The significantly shorter drive axles on a front wheel drive car causes the joint to flex through a much wider degree of motion, compounded by additional stress and angles of steering, while the CV joints of a rear wheel drive car regularly see angles and wear of less than half that of front wheel drive vehicles.
  • The driveshafts may limit the amount by which the front wheels can turn, thus it may increase the turning circle of a front wheel drive car compared to a rear wheel drive one with the same wheelbase.
  • Snap Oversteer. The virtue of weight over the drive wheels also makes the rear end of the car exceptionally light. In a hard cornering situation, slight weight transfer to the front of the car can easily result in a unrecoverable spin.[citation needed]

The factual accuracy of this article is disputed. ... Understeer is a term for a car handling condition during cornering in which the circular path of the vehicles motion is of a greater diameter than the circle indicated by the direction its wheels are pointed. ... Contact patch is the name applied to the area of a vehicles tire that is in contact with the road surface. ... Cross-section through a typical outer CV joint (Saab 96) Constant Velocity Joints or homokinetic or CV joints allow a rotating shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. ... Rear wheel drive was a common form of engine/transmission layout used in automobiles throughout the 20th century. ...

External links

  • What's It Like To Drive - describes a test between two Dodge Daytonas, one FWD and one RWD

  Results from FactBites:
 
Front wheel drive - Wikicars (1776 words)
Front wheel drive was further popularised by the 1948 Citroën 2CV, where the lightweight aluminum flat twin engine was mounted ahead of the front wheels, and 1955 Citroën DS, featuring the mid-engine layout.
All Subaru front wheel drive and all wheel drive layouts are derived from the standard longitudinal front engine/rear drive transmission configuration, however the differential for the front wheels is between the bellhousing and the transmission.
Predictable handling characteristics: front-wheel drive cars, with a front weight bias, tend to understeer at the limit, which is commonly believed to be easier for average drivers to correct than terminal oversteer, and less prone to result in fishtailing or a spin.
FRONT WHEEL DRIVE CYCLE (US3848891) (343 words)
A drive train has a first drive linkage operably connected to front wheel means for rotation of the front wheel upon actuation of the drive train.
front wheel means, means mounting the front wheel means on a front portion of the frame, said means mounting the front wheel means being rotatable about a generally upright axis to steer the cycle;
drive means having a first drive linkage drivably connecting the front wheel with the forward portion of the tiller means and a second drive linkage connecting the first drive linkage and the rear portion of the tiller means, and means for imparting torque to the rear portion of the second drive linkage.
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