Mid-engine design

Central engine is the name given to the arrangement of the motor vehicles between the axles, in the strict sense, a motor-gear unit with the motor from the driven rear axle. For multi-lane motor vehicles, the arrangement is behind or below the passenger, another feature of the mid-engine layout. In a broader sense also arranged between the axes underfloor engines are considered mid-engine. The motor assembly is different from the front-engine and rear-engine arrangement, the demarcation to the front engine is soft: With front-wheel drive in reverse arrangement (gear front, engine behind it) is the engine between the axles shall be regarded as a front engine. In sports car with far disposed behind the front engine, the arrangement is referred to as " front mid- engine " because the feature is met " between the axles', but not the feature " behind the occupants. "

The mid-engine arrangement is mainly in sports and racing cars used, but occasionally also in vans, buses and trucks.

For bicycles with electric drive, for example, Pedelecs, the mid-engine is characterized by the arrangement in the vicinity of the bottom bracket.

History

Even when Gottlieb Daimler Motor Carriage 1886 the engine was installed under and in the rear footwell, but also in other early car designs you will find the engine between the axles, for example, under the driver's seat to the first vehicles from Ford, Packard or Olds. The driving force of the transverse-mounted engines was transferred with chains on the rear wheels. The Auto Union 16-cylinder racing car, which was 1933 developed with the assistance of Ferdinand Porsche, had a mid-engine, as well as the Mercedes -Benz 150, although that was still being referred to as a rear -engine design. The British racing car company Cooper built in 1955 sports prototypes and Formula 2 car with mid-engine, in the Formula 1 racing series all cars are designed since the early 1960s. In the mid-engine bus construction took place after the departure from the front engine temporarily as underfloor engine use before the rear engine arrangement established as the standard. Various truck series, such as by Bussing and MAN were equipped with underfloor engine.

Pros and Cons

By the mid-engine an approximately uniform weight distribution on the front and rear axle is easier, above all, reaches a mass concentration near the center of gravity. From this follows a balanced ride that is characterized neither by lower taxes ( center of gravity in the bow area ) nor by overdriving ( center of gravity in the rear ). So high cornering speeds are possible.

Since the majority of the vehicle weight, therefore, the mass moment of inertia about the vehicle's vertical axis is concentrated in low center of gravity and the crossing of the limit of adhesion results in a curve to a very fast, difficult to control rotation of the mid-engine vehicle. On the other hand, the steering into a curve is very spontaneous, which vehicle is very agile. Furthermore, rotations about the transverse axis / pitch axis (eg braking and squat ) due to the lower inertia pronounced occur and thereby adversely affect the ride comfort and dynamic axle load distribution. The practical utility of automobiles with central engine is usually limited. They often have only a single row of seats, sometimes two luggage compartments in the rear and front available. Depending on the design of a vehicle engine and ancillaries for repairs are sometimes difficult to reach, which may adversely affect the serviceability.

Since the external bow and stern areas of mid-engine vehicles are not taken from the drive unit to complete, more spacious crumple zones can be designed. This increases the passive safety of the occupants. Furthermore arise aerodynamic advantages in the design of the front end.

A special form increasingly more commonly used of the mid-engine is front - mid-engine, which is installed between the front axle and the passenger compartment. This design is similar to the practical value of the conventional drive and was particularly very prevalent in pre-war vehicles.

The mid-engine is combined mainly with rear wheel drive. He has the advantages of compact drive, combined with the low center of gravity. The advantage is no longer the front - mid-engine, there must be recourse here to a propeller shaft and a separate axle differential or on the transaxle design. There is also the connection of the mid-engine with all-wheel drive, but this requires a much more complex drive train around the engine. Mid-engine front-wheel drive in road vehicle plays virtually no role and is used no more than special vehicle or self-propelled machines.

Selection of mid-engine vehicles

  • AC 3000ME
  • Alfa Romeo 4C
  • Aston Martin V8 Vantage ( front mid-engined )
  • ATS 2500 GT
  • Audi R8
  • Auto Union racing cars
  • BMW M1
  • Bussing ( trucks and buses)
  • Daimler Motor Carriage
  • De Tomaso Pantera
  • Ferrari F430
  • Fiat X1 / 9

Use in aircraft

Means engines were also used in aviation, for example, in the Bell P -39 Airacobra and the Bell P- 63 King Cobra. These fighter aircraft maneuverability should be increased by the placement of the engine in the aircraft center. Ultimately, however, the design principle did not prevail.

The Dornier Do 335 was an unconventional two -engined aircraft, with a front engine for the tractor propeller at the bow and a central engine for the pusher propeller at the rear.

Front-engine design Rear-engine design Packard Model G Ransom E. Olds Transverse engine Formula Two Automobili Turismo e Sport Koenigsegg CCR Lamborghini Murciélago Matra Bagheera Mazda RX-8 MG F / MG TF Rumpler-Tropfenwagen Bell P-63 Kingcobra
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