All-wheel drive vehicle: Difference between revisions

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An all-wheel drive vehicle (AWD vehicle) is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand.

Types

The most common forms of all-wheel drive are:

1x1: All unicycles
Reflects one axle with one wheel capable of being powered.
2x2: Some motorcycles and bikes
Reflects two axles with one wheel on each capable of being powered.
4×4 (also, four-wheel drive or 4WD): Reflects two axles with both wheels on each capable of being powered.
6×6 (also, six-wheel drive or 6WD): Reflects three axles with both wheels on each capable of being powered.
8×8 (also, eight-wheel drive or 8WD): Reflects four axles with both wheels on each capable of being powered.

Vehicles may be either part-time all-wheel drive or full-time:

On-demand or Part-time: One axle is permanently connected to the drive, the other is connected as needed
Full-time or Permanent: All axles are permanently connected, with or without a differential.
Independent: The wheels are driven, but not dependent on a central mechanical power coupling.

Terminology

Particularly in North America for several decades, the designation AWD has been used and marketed – distinctly from 4×4 and 4WD – to apply to vehicles with drive train systems that have permanent drive, a differential between the front and rear drive shafts, and active management of torque transfer, especially following the advent of the anti-lock braking system (ABS).

However, the designations AWD^[1] and all-wheel drive^[2] long predated the trend, with Associated Equipment Company (AEC) producing AWD trucks in 1929 in conjunction with the British subsidiary of the pioneering American firm Four Wheel Drive Auto Company. Additionally, General Motors began manufacturing a line as "all-wheel drive" as early as the late 1930s. This distinction in terminology is not generally used outside North America.^{[citation needed]}

In the context of hybrid and electric vehicles, the North American designation of 'all-wheel-drive' may differ. In some hybrid vehicles, the combustion engine is only mechanically connected to the front wheels, while the rear wheels are powered independently by an electric motor; this may be marketed as eAWD. Furthermore, many electric vehicles have individual, unconnected motors powering each axle, or even each individual wheel, also without any center differential.

Characteristics

When tire grip is good during road driving, a differential is used between the axles to avoid driveline windup. This is not required off-road, as the limited grip allows the tires to slip. All-wheel drive vehicles designed for extensive off-road use may not have such a differential, and so they suffer from wind-up when used on-road.^[3] Selectable 4WD also avoids this problem and requires only a simple dog clutch in the transfer case, rather than a differential. For this reason, most early off-road vehicles used that system; e.g., Jeep, Land Rover.

As vehicles became more sophisticated and tires gave better winter performance in the 1960s, there was an interest in giving the benefits of all-wheel drive to conventional cars: not for off-road use but for winter use in snow or on wet roads. Exotic vehicles such as the high-powered Jensen FF followed by the AMC Eagle, Subaru Leone and Audi Quattro series were the first to offer all-wheel drive in a high-speed road-based car. These, particularly the Quattro, would extensively develop this drivetrain with the use of viscous couplings and differentials to provide a safe and drivable car. The first off-road / on-road hybrids such as the Range Rover also chose the permanent all-wheel-drive system rather than manual selection.

References

^ "Automotive History". allisons.org. Australia. Retrieved 24 October 2024. 1929: AEC started to build AWD trucks in conjunction with FWD (UK)
^ Meyer, Donald E. "The first century of GMC truck history" (PDF). Archived from the original (PDF) on 9 January 2014 – via GM Heritage Center. By December [1939], GMC had orders for more than 4,400 all-wheel-drive military trucks.
^ Ware, Pat (1994). In National Service. Warehouse Publications. p. 118. ISBN 0-9525563-0-8.

[1] "Automotive History". allisons.org. Australia. Retrieved 24 October 2024. 1929: AEC started to build AWD trucks in conjunction with FWD (UK)

[2] Meyer, Donald E. "The first century of GMC truck history" (PDF). Archived from the original (PDF) on 9 January 2014 – via GM Heritage Center. By December [1939], GMC had orders for more than 4,400 all-wheel-drive military trucks.

[3] Ware, Pat (1994). In National Service. Warehouse Publications. p. 118. ISBN 0-9525563-0-8.

[1]

[2]

[3]

@@ Line 1: / Line 1: @@
+{{Short description|Powertrain providing power to all its wheels for use primarily on paved surfaces}}
-{{refimprove|date=March 2015}}
+{{Use dmy dates|date=September 2021}}
-[[File:Jeep Wrangler TJ.jpg|thumb|right|The [[Jeep Wrangler]] is a [[4×4]] four-wheel drive vehicle equipped with a low-range gearbox, which provides the driver with a selection between low range or high range gearing]]
+[[File:Jeep Wrangler TJ.jpg|thumb|right|The [[Jeep Wrangler]] is a [[Four-wheel drive|4×4]] four-wheel drive vehicle equipped with a low-range gearbox, which provides the driver with a selection between low range or high range gearing]]
 [[Image:Hayes Arbegui 2010.JPG|thumb|[[Hayes Truck|Hayes]] WHDX 70-170 [[6×6]] tractor]]
-[[File:M1070 HET in Fort Knox.jpg|thumb|The [[eight-wheel drive|8×8]] [[tractor unit]] of the [[Heavy Equipment Transport System|HETS]] heavy equipment transport system]]
+[[File:M1070 HET in Fort Knox.jpg|thumb|The [[eight-wheel drive|8×8]] [[tractor unit]] of the [[Heavy Equipment Transport System|HETS]] (heavy equipment transport system)]]
 An '''all-wheel drive vehicle''' ('''AWD vehicle''') is one with a [[powertrain]] capable of providing power to all its wheels, whether full-time or on-demand.
+== Types ==
 The most common forms of all-wheel drive are:
-;[[4×4]] (also, four-wheel drive and 4WD): Reflecting two axles with both wheels on each capable of being powered.
+;1x1 : All [[unicycle]]s <br>Reflects one axle with one wheel capable of being powered.
-;[[6×6]] (also, six-wheel drive and 6WD): Reflecting three axles with both wheels on each capable of being powered.
+;[[Two-wheel drive|2x2]] : Some motorcycles and bikes <br>Reflects two axles with one wheel on each capable of being powered.
-;[[eight-wheel drive|8×8]] (also, eight-wheel drive and 8WD): Reflecting four axles with both wheels on each capable of being powered.
+;[[4×4]] (also, four-wheel drive or 4WD): Reflects two axles with both wheels on each capable of being powered.
+;[[6×6]] (also, six-wheel drive or 6WD): Reflects three axles with both wheels on each capable of being powered.
+;[[eight-wheel drive|8×8]] (also, eight-wheel drive or 8WD): Reflects four axles with both wheels on each capable of being powered.
 Vehicles may be either part-time all-wheel drive or full-time:
-;On-demand (also, part-time): One axle is permanently connected to the drive, the other is being connected as needed
+;On-demand or Part-time: One axle is permanently connected to the drive, the other is connected as needed
-;Full-time (also, permanent): All axles are permanently connected, with or without a [[differential (mechanical device)|differential]].
+;Full-time or Permanent: All axles are permanently connected, with or without a [[differential (mechanical device)|differential]].
-;Independent : The wheels are driven, but not dependent on a transaxle. [[Tesla]]'s vehicles ([[Model S]] and [[Model X]]) are so far the only ones to use such a system.
+;Independent: The wheels are driven, but not dependent on a central mechanical power coupling.
+==Terminology==
-==Usage of the terminology==
+Particularly in North America for several decades, the designation ''AWD'' has been used and marketed – distinctly from ''4×4'' and ''4WD'' – to apply to vehicles with drive train systems that have permanent drive, a [[differential (mechanical device)|differential]] between the front and rear drive shafts, and active management of torque transfer, especially following the advent of the [[anti-lock braking system]] (ABS).
-Today, the designation ''AWD'' is becoming narrowed, particularly in North America, to apply to vehicles with drive train systems that have permanent drive and usually include a [[differential (mechanical device)|differential]] between the front and rear drive shafts. However, the designations ''AWD''<ref>Allisons.org ''Automotive History'' [http://www.allisons.org/ll/4/History/ ]"1929: AEC started to build AWD trucks in conjunction with FWD (UK)"</ref> and ''all-wheel drive''<ref>MEYER, DONALD E. ''THE FIRST CENTURY OF GMC TRUCK HISTORY'' [https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/GMC/100_YR_GMC_HISTORY_MAR09.pdf] "By December <nowiki>[1939]</nowiki>, GMC had orders for more than 4,400 all-wheel-drive military trucks."</ref> long predated the trend, with [[Associated Equipment Company]] (AEC) building AWD trucks in conjunction with [[Four Wheel Drive|FWD]] (UK) in 1929, and [[General Motors]] manufacturing a line as "all-wheel drive" as early as the late 1930s.  This distinction in terminology is not generally used outside North America.
+However, the designations ''AWD''<ref>{{cite web |website=allisons.org |title=Automotive History |url=http://www.allisons.org/ll/4/History/ |quote=1929: AEC started to build AWD trucks in conjunction with FWD (UK) |access-date=2024-10-24 |location=Australia}}</ref> and ''all-wheel drive''<ref>{{cite web |last=Meyer |first=Donald E. |title=The first century of GMC truck history |url=https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/GMC/100_YR_GMC_HISTORY_MAR09.pdf |archive-url=https://web.archive.org/web/20140109015322/https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/GMC/100_YR_GMC_HISTORY_MAR09.pdf |archive-date=2014-01-09 |url-status=dead |quote=By December [1939], GMC had orders for more than 4,400 all-wheel-drive military trucks. |via=GM Heritage Center}}</ref> long predated the trend, with [[Associated Equipment Company]] (AEC) producing AWD trucks in 1929 in conjunction with the British subsidiary of the pioneering American firm [[Four Wheel Drive|Four Wheel Drive Auto Company]]. Additionally, [[General Motors]] began manufacturing a line as "all-wheel drive" as early as the late 1930s. This distinction in terminology is not generally used outside North America.{{Cn|date=June 2024}}
+In the context of [[Hybrid electric vehicle|hybrid]] and [[Electric vehicle|electric vehicles]], the North American designation of 'all-wheel-drive' may differ. In some hybrid vehicles, the combustion engine is only mechanically connected to the front wheels, while the rear wheels are powered independently by an electric motor; this may be marketed as ''eAWD''. Furthermore, many electric vehicles have individual, unconnected motors powering each axle, or even each individual wheel, also without any center differential.
 ==Characteristics==
-{{see|Four-wheel drive#SAE_Recommended_Practices}}
+{{Further|Four-wheel drive#SAE recommended practices}}
 When tire grip is good during road driving, a [[differential (mechanical device)|differential]] is used between the axles to avoid [[driveline windup]]. This is not required off-road, as the limited grip allows the tires to slip. All-wheel drive vehicles designed for extensive off-road use may not have such a differential, and so they suffer from wind-up when used on-road.<ref>{{Cite book
   |title=In National Service
@@ Line 27: / Line 35: @@
   |year=1994
   |isbn=0-9525563-0-8
-  |ref=harv
   |page=118
 }}</ref> Selectable 4WD also avoids this problem and requires only a simple [[dog clutch]] in the [[transfer case]], rather than a differential. For this reason, most early off-road vehicles used that system; e.g., [[Jeep]], [[Land Rover Series|Land Rover]].
-As vehicles became more sophisticated and tires gave better winter performance in the 1960s there was an interest in giving the benefits of all-wheel drive to conventional cars; not for off-road use but for winter use in snow or on wet roads. Exotic vehicles such as the high-powered [[Jensen FF]] followed by the [[AMC Eagle]], [[Subaru Leone]] and [[Quattro (four-wheel-drive system)|Audi Quattro]] series were the first to offer all-wheel drive in a high-speed road-based car. These, particularly the Quattro, would extensively develop this drivetrain with the use of [[viscous coupling]]s and differentials to provide a safe and drivable car. The first off-road / on-road hybrids such as the [[Range Rover Classic|Range Rover]] also chose the permanent all wheel drive system rather than manual selection.
+As vehicles became more sophisticated and tires gave better winter performance in the 1960s, there was an interest in giving the benefits of all-wheel drive to conventional cars: not for off-road use but for winter use in snow or on wet roads. Exotic vehicles such as the high-powered [[Jensen FF]] followed by the [[AMC Eagle]], [[Subaru Leone]] and [[Quattro (four-wheel-drive system)|Audi Quattro]] series were the first to offer all-wheel drive in a high-speed road-based car. These, particularly the Quattro, would extensively develop this [[drivetrain]] with the use of [[viscous coupling]]s and differentials to provide a safe and drivable car. The first off-road / on-road hybrids such as the [[Range Rover Classic|Range Rover]] also chose the permanent all-wheel-drive system rather than manual selection.
-Selectable 4WD has both axles rigidly coupled together, which has some advantages in very poor off-road conditions. To gain the same advantage in a permanent AWD system with a differential, the differential can be locked manually with a differential lock. As this control is frequently misunderstood and mis-used, which can then cause damage due to wind-up, they have tended to be replaced by automatic locking through the viscous couplers.
 ==See also==
+{{div col|colwidth=23em}}
+*[[All-terrain vehicle]]
+*[[Four Wheel Drive]] or FWD, one of the first companies, from 1909, to build four-wheel drive vehicles.
 *[[Front-wheel drive]]
+* [[H-drive]]
+*[[Individual wheel drive]] (IWD)
 *[[Rear-wheel drive]]
-*[[All-terrain vehicle]]
 *[[Two-wheel drive]]
+{{div col end}}
-*[[H-drive]]
-*[[Four Wheel Drive]] or FWD, one of the first companies, from 1909, to build four-wheel drive vehicles.
 == References ==
@@ Line 48: / Line 56: @@
 {{Automobile configuration}}
+{{Authority control}}
+{{DEFAULTSORT:All-Wheel Drive Vehicle}}
-{{Use dmy dates|date=August 2011}}
-{{DEFAULTSORT:All-Wheel Drive}}
 [[Category:Off-road vehicles]]
-[[Category:Automobile layouts]]
+[[Category:Car layouts]]
-[[Category:Automotive technologies]]
+[[Category:Drivetrain]]