This articleneeds additional citations forverification.(October 2021) |
Inautomotive design,anF4,orfront-engine, four-wheel drive (4WD) layoutplaces theinternal combustion engineat the front of the vehicle and drives all four roadwheels. Thislayoutis typically chosen for better control on many surfaces, and is an important part ofrallyracing, as well asoff-roaddriving. In terms of racing purposes, whether it be on-road or off-road, can be described as follows,
![](https://upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Automotive_diagrams_02C_En.png/275px-Automotive_diagrams_02C_En.png)
A team that pursues the Weak LS4WD architecture will minimize the development cost of thefront-wheel drivesystem 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.[1]
Most four-wheel-drive layouts are front-engined and are derivatives of earlierfront-engine, rear-wheel drive,orfront-engine, front-wheel drivedesigns. 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 engineerJoseph Diplockpatented a four-wheel-drive system for a traction engine, while in Vienna, Austria,Ferdinand Porschedeveloped 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.[2]However, the 1903Spyker 60 HPwas the first car built with an F4 drive layout.[3]
This layout is also the drive train of choice for off-roadpickup trucksandSUVs.It allows these vehicles to get the most traction without sacrificing cargo or passenger room. Part-time four-wheel drive vehicles frequently have atransfer caseand no centerdifferential,meaning, in many cases, the 4WD mode does not allow any difference in front and rear axle speeds. For normal road driving, these vehicles are shifted into2WDmode, 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.[4]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.[5]
Several four-wheel-drive vehicles have been built without adrive shaftbetween the front combustion engine and rear wheels; instead the rear wheels receive power and torque from a rearelectric motor.This setup has been mainly used byhybrid electric vehicles,although some conventional vehicles had also adopted the system.[6]
Examples
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1943Willys Jeep
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ATroller T4jeep
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2008–2009Jeep Liberty
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Center transfer case sending power from the transmission to the rear axle (right) and front axle (left)
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First-generationDodge Power Wagon
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Nissan Skyline GT-RV Spec II (BNR34)
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Subaru WRXSTI
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Ferrari FF;with a front mid-engine, four-wheel-drive layout
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Toyota Celica GT-Four(ST205)
References
edit- ^Owen, Elliot Douglas (June 2018).The Benefits of Four-Wheel Drive for a High-Performance FSAE Electric Racecar(PDF)(Thesis).Massachusetts Institute of Technology.OCLC1080309406.Retrieved2 October2021.
- ^"The Origins of Four-Wheel Drive".Hemmings Motor News.December 2019.Retrieved5 May2021.
- ^Malcolm McKay (March 2008)."Four-wheel drive – The Knowledge".Octane magazine. Archived fromthe originalon 3 May 2009.Retrieved24 May2009.
- ^"How 4WD, FWD, RWD and AWD all Work?".Car Decent.16 February 2023.Retrieved1 April2023.
- ^Markovich, Tony (17 July 2020)."AWD vs. 4WD: Know the Differences".The Drive.Retrieved5 May2021.
- ^"Which Hybrids Have All-Wheel Drive?".AutoTrader.ca.26 August 2020.Retrieved23 April2022.