Rear-engine design

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In automobile design, a rear-engine design layout places the engine at the rear of the vehicle. The center of gravity of the engine itself is behind the rear axle. This is not to be confused with the center of gravity of the whole vehicle, as an imbalance of such proportions would make it impossible to keep the front wheels on the ground.

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Rear-engine position / Rear-wheel drive Automotive diagrams 05 En.png
Rear-engine position / Rear-wheel drive

Rear-engined vehicles almost always have a rear-wheel drive car layout, but some are four wheel drive. This layout has the following features:

This layout was once popular in small, inexpensive cars and light commercial vehicles. Today most car makers have abandoned the layout although it does continue in some expensive cars, [3] like the Porsche 911. It is also used in some racing car applications, [4] low-floor buses, some Type-D school buses, and microcars such as the Smart Fortwo. Some electric cars feature both rear and front motors, to drive all four wheels. [5]

Notable rear-engined cars

Smart Fortwo's three-cylinder engine officially sits behind the rear axle. Smart Fortwo.jpg
Smart Fortwo's three-cylinder engine officially sits behind the rear axle.

See also

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Flat engine

A flat engine, also known as a horizontally opposed engine, is a piston engine where the cylinders are located on either side of a central crankshaft. It is effectively a V engine with a 180-degree angle between the cylinder banks. A flat engine should not be confused with the opposed-piston engine, in which each cylinder has two pistons sharing a central combustion chamber.

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Chevrolet Corvair Compact automobile

The Chevrolet Corvair is a compact car manufactured by Chevrolet for model years 1960–1969 in two generations. It remains the only American-designed, mass-produced passenger car with a rear-mounted, air-cooled engine. The Corvair was manufactured and marketed in 4-door sedan, 2-door coupe, convertible, 4-door station wagon, passenger van, commercial van, and pickup truck body styles in its first generation (1960–1964) and as a 2-door coupe, convertible or 4-door hardtop in its second (1965–1969) — with a total production of approximately 1.8 million from 1960-1969.

Front-wheel drive

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Rear-engine, rear-wheel-drive layout

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 buses, this layout has become increasingly rare in passenger cars.

Rear mid-engine, rear-wheel-drive layout

In automotive design, an RMR, or rear mid-engine, rear-wheel-drive layout, is one in which the rear wheels are driven by an engine placed just in front of them, behind the passenger compartment. In contrast to the rear-engined RR layout, the center of mass of the engine is in front of the rear axle. This layout is typically chosen for its low moment of inertia and relatively favorable weight distribution. The layout has a tendency toward being heavier in the rear than the front, which allows for best balance to be achieved under braking. However, since there is little weight over the front wheels, under acceleration, the front of the car is prone to lift and cause understeer. Most rear-engine layouts have historically been used in smaller vehicles, because the weight of the engine at the rear has an adverse effect on a larger car's handling, making it 'tail-heavy'. It is felt that the low polar inertia is crucial in selection of this layout. The mid-engined layout also uses up central space, making it impractical for any but two-seater sports cars. However, some microvans use this layout, with a small, low engine beneath the loading area. This makes it possible to move the driver right to the front of the vehicle, thus increasing the loading area at the expense of slightly reduced load depth.

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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.

Transaxle

A transaxle is a single mechanical device which combines the functions of an automobile's transmission, axle, and differential into one integrated assembly. It can be produced in both manual and automatic versions.

Flat-six engine

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Smart Fortwo Automobile model

The Smart Fortwo is a rear-engine, rear-wheel-drive, 2-passenger hatchback microcar manufactured and marketed by the Smart division of the German multinational Daimler AG, introduced in 1998, now in its third generation.

Smart Forfour Motor vehicle

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The 2006 Paris Motor Show took place from 30 September to 15 October 2006, in Paris expo Porte de Versailles, Paris, France.

Kelmark Engineering

Kelmark Engineering was an automotive specialty shop established in 1969 and based in Okemos, Michigan. It focused on high-performance custom V8 drivetrain swaps, the modification and production of rear and mid-engined cars, and custom-built turn-key automobiles. Until 1986, Kelmark Engineering manufactured kits and complete, finished, turn-key vehicles which were either Volkswagen-based or built on tubular race car-type frames. The outfit gained its name from Russ Keller and Randy Markham, the two co-creators who started the operation. Up until at least 1989, the Kelmark GT was still available as a kit albeit the manufacturer was Kelmark Motors in Holt, Michigan. The cars are all "rare" models, but the Volkswagen-powered Kelmark GT was the most popular.

Rear-engine, four-wheel-drive layout

In automotive design, an R4, or Rear-engine, Four-wheel-drive layout places the internal combustion engine at the rear of the vehicle, and drives all four roadwheels.

References

  1. "1965 Chevrolet Corvair" . Retrieved 16 March 2019.
  2. "What Is Rear Engine Layout And Know How Is It Beneficial?" . Retrieved 16 March 2019.
  3. Threewitt, Cherise. "10 Affordable Rear Engine Cars" . Retrieved 16 March 2019.
  4. Wong, J. Y. (2008). Theory of Ground Vehicles. Hoboken NJ: Wiley. p. 560. ISBN   0-471-35461-9.
  5. Adams, Eric. "The Secrets of Electric Cars and Their Motors: It's Not All About the Battery, Folks" . Retrieved 16 March 2019.
  6. Golseth, Andrew. "Why Is The Chevrolet Corvair Such An Overlooked Classic?" . Retrieved 16 March 2019.