Front-engine, rear-wheel drive layout
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In automotive design, an FR, or Front-engine, Rear-wheel drive layout is one where the engine is located at the front of the vehicle and driven wheels are located at the rear. This was the traditional automobile layout for most of the 20th century.[1]
[edit] Overview
The FR layout is often chosen for its simple design and good handling characteristics. Placing the drive wheels at the rear allows ample room for the transmission in the center of the vehicle and avoids the mechanical complexities associated with transmitting power to the front wheels. For performance-oriented vehicles, the FR layout is more suitable than front-wheel drive designs, especially with engines that exceed 200 horsepower. This is because weight transfers to the rear of the vehicle during acceleration, which loads the rear wheels and increases their grip.
Another advantage of the FR layout is relatively easy access to the engine compartment, as result of the longitudinal orientation of the drivetrain, as compared to the FF layout (front-engine, front-wheel drive).
The FMR layout is based on the FR layout.
[edit] History
The first FR car was an 1895 Panhard model, so this layout was known as the "Système Panhard" in the early years. Most American cars used the FR layout until the mid 1980s. The Oil crisis of the 1970s and the success of small FF cars like the Mini, Volkswagen Golf, and Honda Civic led to the widespread adoption of that layout.
Some manufacturers, such as Alfa Romeo, Porsche (944, 924, 928) and Chevrolet (C5 and C6 Corvettes), retained this layout but moved the gearbox from behind the engine to between the rear wheels, putting more weight over the driven axle. This configuration is often referred to as a transaxle since the transmission and axle are one unit.
After the Arab Oil Embargo of 1973 and the 1979 fuel crises, a majority of American FR vehicles (station wagons, luxury sedans) were phased out for the FF layout - this trend would spawn the SUV/van conversion market. Throughout the 1980s and 1990s, most American companies set as a priority the eventual removal of rear-wheel drive from their mainstream and luxury lineup.[2] Chrysler went 100% FF by 1990 and GM's American production went entirely FF by 1997 except the Corvette and Camaro. Ford's full-size cars (the Ford Crown Victoria, Mercury Grand Marquis, and Lincoln Town Car) have always been FR[3], as was the Ford Mustang[4] and Lincoln LS.
In Australia, FR cars have remained popular throughout this period, with the Holden Commodore and Ford Falcon having consistently strong sales. In Europe, front-wheel drive was popularized by small cars like the Mini, Renault 5 and Volkswagen Golf and adopted for virtually all mainstream cars. Upscale marques like Mercedes-Benz, BMW, and Jaguar remained mostly independent of this trend, and retained a lineup mostly or entirely made up of FR cars.[5] Japanese mainstream marques such as Toyota and Honda became mostly or entirely FF early on, while reserving for their latterly-conceived luxury divisions (Lexus and Acura, respectively) a mostly FR lineup.
Currently most cars are FF, including virtually all front-engined economy cars, though FR cars are making a return as an alternative to large sport-utility vehicles. In North America, GM returned to production of the FR luxury car with the 2003 Cadillac CTS, and with the removal of the DTS[6], Cadillac will be entirely FR (with four-wheel drive available as an option on several models) by 2010, and the 2009 Camaro returns as a FR sports car. Chrysler returned its full-size cars to this layout with the Chrysler 300 and related models.[7][8] Ford never eliminated FR cars, but is looking to replace the dated designs that it currently has.[9]
[edit] References
- ^ Development of a New Hybrid Transmission for RWD Car. www.sae.org. Retrieved on 2008-01-11.
- ^ http://www.popularmechanics.com/automotive/new_cars/1266931.html
- ^ http://blog.vehiclevoice.com/2005/12/why_good_enough_isnt_1.html
- ^ http://www.popularhotrodding.com/features/0501phr_2005_ford_mustang/index.html
- ^ http://www.rearwheeldrive.org/rwd/rwdrate.htm
- ^ http://dfwdriveyourdream.com/blog/cadillac-dts-to-be-discontinued/1126
- ^ http://www.slate.com/id/2082761
- ^ http://www.leftlanenews.com/2011-chrysler-300-dodge-charger-to-remain-rear-wheel-drive.html
- ^ http://www.detnews.com/apps/pbcs.dll/article?AID=/20080324/AUTO01/803240338/1148
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