Rear-engine, front-wheel-drive layout

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Framed illustration of the Dymaxion car. Dymaxion car illustration.jpg
Framed illustration of the Dymaxion car.

A rear-engine, front-wheel-drive layout is one in which the engine is between or behind the rear wheels, and drives the front wheels via a driveshaft, the complete reverse of a conventional front-engine, rear-wheel-drive vehicle layout.

The earliest example of the form appeared in 1932, with the design and construction of the prototype Maroon Car by chief designer Harleigh Holmes at Coleman Motors, an established builder of Front- and All-Wheel-Drive vehicles based in Littleton, Colorado. [1] The car had front-wheel drive and was powered by a rear-mounted V-8 engine. Only one was built and the vehicle was never placed in production. [2]

Since then, it has remained an extremely uncommon drive layout throughout automotive history, used only by a few prototypes and concept cars, such as the 1937 Howie machine gun carrier (nicknamed "belly flopper"), [3] Buckminster Fuller's 1933 Dymaxion car, which was able to turn within its wheelbase thanks to rear-wheel steering, [4] and the 1947 Gregory Sedan. [5]

The layout has occasionally seen renewed interest as a potential option for innovative car designs, such as in the 1999 patent application of inventor–engineer Michael Basnett at the former Rover Group, which proposed a front transaxle, rear quasi-flat engine (an inline-4, turned 90 degrees) architecture, with the fuel tank placed where the right-hand cylinder bank would have been in a "true" flat engine; overall somewhat mimicking the "pancake engine" design of the Volkswagen Type 3 but in water-cooled form and without rear drive.

According to the patent, the layout is designed to be advantageous in terms of crash performance by increasing the front crumple zone, in allowing greater styling freedom, in enhanced ride via reduced noise, vibration, and harshness, and in lowered center of gravity providing improved handling, braking and roll characteristics—as well as, much like the Type 3, increased cabin and cargo space within the same chassis footprint and body height. Its main disadvantage is the lack of weight over the drive wheels, particularly under hard acceleration as weight shifts to the rear.

However, as mentioned in a Jalopnik article listing all known RF-layout cars, [6] it too appears to have been nothing more than a speculative exercise, without so much as a single physical prototype being built—and the point of whether Rover Group intended to develop it any further is moot, as the corporation was broken up and its assets sold off barely a year later, with the fate of that particular piece of IP being unclear.

The drivetrain design closest to RF in actual series production vehicles is the mid-engine, four-wheel-drive layout, typically seen in high end sportscar designs, and which, with the use of power-split centre differentials or hybrid drive systems, can be set up to send a variable amount of the total drive to the front wheels, in some cases up to 100%. Electric front-wheel-drive vehicles can also be found with small range-extender motor-generators, which are typically mounted in the rear luggage compartment, but do not technically count as RF drivetrain as there is no direct mechanical link between engine and wheels, or even the generated engine power and drive motor output, as the generator tends to run at a constant speed and is used to maintain battery charge rather than power the motor directly.

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Dymaxion car concept car designed by American inventor Buckminster Fuller

The Dymaxion car was designed by American inventor Buckminster Fuller during the Great Depression and featured prominently at Chicago's 1933/1934 World's Fair. Fuller built three experimental prototypes with naval architect Starling Burgess – using donated money as well as a family inheritance – to explore not an automobile per se, but the 'ground-taxiing phase' of a vehicle that might one day be designed to fly, land and drive – an "Omni-Medium Transport". Fuller associated the word Dymaxion with much of his work, a portmanteau of the words dynamic, maximum, and tension, to summarize his goal to do more with less.

Four-wheel drive type of drivetrain with four driven wheels

Four-wheel drive, also called 4x4 or 4WD, refers to 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.

Front-wheel drive

Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel-drive and four-wheel drive vehicles.

Front-engine, front-wheel-drive layout Term used in automotive technology

In automotive design, an FF, or front-engine, front-wheel-drive (FWD) layout places both the internal combustion engine and driven roadwheels at the front of the vehicle.

Rear-engine, rear-wheel-drive layout term used in automotive technology

In automotive design, an RR, or rear-engine, rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the rear axle and the rear bumper. Although very common in transit buses and coaches due to the elimination of the drive shaft with low-floor bus, this layout has become increasingly rare in passenger cars.

Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, where the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-wheel drive vehicles feature a longitudinally mounted engine at the front of the car.

Powertrain system that powers a vehicle

In a motor vehicle, the powertrain comprises the main components that generate power and deliver that power to the road surface, water, or air. This includes the engine, transmission, drive shafts, differentials, and the final drive. Hybrid powertrains also include one or more electric traction motors that operate to drive the vehicle wheels. All-electric vehicles eliminate the engine altogether, relying solely on electric motors for propulsion. Occasionally the term powerplant is casually used to refer to the engine or, less often, the entire powertrain.

Acura Legend Mid-size luxury/executive car

The Acura Legend is a mid-size luxury/executive car manufactured by Honda. It was sold in the U.S., Canada, and parts of China under Honda's luxury brand, Acura, from 1985 to 1995, as both a sedan, which was classified as a full-size car, and a coupe, which was classified as a mid-size car. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was the North American version of the KA9 series Honda Legend.

Mazda Sentia Executive car produced by Mazda

The Mazda Sentia is a mid-size rear wheel drive luxury car that was sold by Mazda in Japan from 1991 to 1999 over two generations. It replaced the Mazda Luce nameplate on the Mazda H platform, and continued the tradition of being Mazda's largest flagship sedan, which had been in production since the late 1960s.

Hybrid Synergy Drive (HSD), also known as Toyota Hybrid System II, is the brand name of Toyota Motor Corporation for the hybrid car drive train technology used in vehicles with the Toyota and Lexus marques. First introduced on the Prius, the technology is an option on several other Toyota and Lexus vehicles and has been adapted for the electric drive system of the hydrogen-powered Mirai, and for a plug-in hybrid version of the Prius. Previously, Toyota also licensed its HSD technology to Nissan for use in its Nissan Altima Hybrid. Its parts supplier Aisin Seiki Co. offers similar hybrid transmissions to other car companies.

Drive wheel

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.

Autobianchi Primula car model

The Autobianchi Primula is a supermini economy car manufactured between 1964 and 1970 by the Italian automaker Autobianchi, partly owned by and later a subsidiary of the Fiat Group. The Primula was a prototype for Fiat's rack and pinion steering and is widely known for its innovative Dante Giacosa-designed front-wheel drive, transverse engine layout — that would be later popularized by the Fiat 128 to ultimately become an industry-standard front drive layout.

Transverse engine head gas-kit

A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the direction of travel. Many modern front-wheel drive vehicles use this engine mounting configuration. Most rear-wheel drive vehicles use a longitudinal engine configuration, where the engine's crankshaft axis is parallel with the direction of travel, except for some rear-mid engine vehicles, which use a transverse engine and transaxle mounted in the rear instead of the front. Despite typically being used in light vehicles, it is not restricted to such designs and has also been used on armoured fighting vehicles to save interior space.

Super Handling-All Wheel Drive or SH-AWD is a full-time, fully automatic all-wheel drive traction and handling system combines front-rear torque distribution control with independently regulated torque distribution to the left and right rear wheels to freely distribute the optimum amount of torque to all four wheels in accordance with driving conditions." The system was announced in April 2004, and first 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 layout of a motorised vehicle such as a car is often defined by the location of the engine and drive wheels.

The following outline is provided as an overview of and topical guide to automobiles:

Front-engine, four-wheel-drive layout

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.

Lohner-Porsche car model

The Lohner-Porsche Mixed Hybrid was the first hybrid vehicle and was developed by Ferdinand Porsche at Lohner-Werke. First prototypes were two-wheel drive, battery-powered electric vehicles with two front-wheel hub-mounted motors. A later version was a series hybrid using hub-mounted electric motors in each wheel, powered by batteries and a gasoline-engine generator.

Drivetrain Group of components that deliver power to the driving wheels

The drivetrain of a motor vehicle is the group of components that deliver power to the driving wheels. This excludes the engine or motor that generates the power. In contrast, the powertrain is considered to include both the engine or motor and the drivetrain.

Subaru Hybrid Tourer

The Subaru Hybrid Tourer is a hybrid concept sport utility/grand touring vehicle designed and built by Subaru, unveiled at the 2009 Tokyo Motor Show. The Hybrid Tourer included several signature Subaru design features, such as the use of a horizontally-opposed engine and all-wheel drive, and built on prior Subaru hybrid concepts such as the B9SC and B5-TPH by using a two-motor layout. The Hybrid Tourer was succeeded by the 2011 Advanced Tourer concept and the 2013-15 VIZIV diesel hybrid concept series.

References

  1. Harleigh Holmes and the Coleman Motor Company Littleton government history webpage
  2. Hearst Magazines (August 1932). "Rear Engine and Front Drive in Same Auto". Popular Mechanics. Hearst Magazines. p. 250.
  3. "The Car That Inspired The Jeep Was Completely Bonkers". 28 January 2016. Archived from the original on 28 January 2016.
  4. www.thirteen.org Dymaxion Transport. accessed 21 March 2010
  5. "Gregory Sedan- 1947". Lane Motor Museum.
  6. "This Chart Shows Every Car With The Worst, Weirdest Layout In Auto Design". Jalopnik.