Benefits of Flat Engines

With numerous engine architecture and layouts in the market, flat engines, used by a minority of vehicles still impress the most.

A glance at the speedometer of a supercar revving beyond the 8K rpm mark, depicts an image of the whirlwind going on under the hood. All the power churned from the vortex, needs to be delivered to the final element of the drive-train: The wheel. That’s where all trouble pops up in the shape of heat and vibration – the biggest deterrent to smooth power delivery.
Automobile manufacturers have invested astronomical amounts of time and resources to reduce the side effects. Potent vibration elimination could finally be achieved by different engine mounting techniques and ignition components, and most importantly the cylinder layout; inline, V, W and so on.
The most successful in the quest so far has been the flat engine configuration. Also known as Boxer engine or Horizontally Opposed engine, the concept was conceived and invented by famous German engine designer and automobile engineer Karl Benz. Patented in 1896, the engine aimed to minimise vibrations and maintain a low centre of gravity while returning superb fuel efficiency.
Unlike the conventional vertically placed engines, the horizontally placed flat engines are a self deterrent to vibrations due to the movement of the horizontally placed, counter-positioned pistons cancelling out each other’s action reaction by obeying Newton’s third law and provide excellent fuel economy due to the linear flow of power to the transmission.
Imagine a pack of cigarettes lying horizontally on its back versus vertical, and the difference in stability is easy to imagine. That’s exactly how the flat engine is superior to the vertically placed conventional ones in cutting out on vibrations.
Lying on its back rather than being up on feet, the centre of gravity of a vehicle with flat engine is much lower and has more stability. The flat engines also inherently happen to be much safer during the event of a head-on collision, as they fall below the passenger compartment rather than on it.
While flat engines may seem perfect, their implementation is limited to a very few brands. The flat layout is the secret of Porsches’ phenomenal performance from smaller capacity engines. The only other brand to majorly employ the boxers is Subaru.
A major reason is that adopting to the technology requires reinventing the entire powertrain including transmission cabin relocation: A rather expensive improvisation. Other disadvantages maybe the wide size, challenging maintenance and the fact that using it for higher number of cylinders makes it quite an impractical design to fit under the hood.
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