A horizontally opposed engine is an engine design in which the two cylinder heads are on opposite sides of the crankshaft, resulting in a flat profile. Subaru and Porsche are two automakers that use horizontally opposed engines in many of their vehicles.

Most engines are inline or V designs, in which the cylinders are all in a line or the planes of the two separate cylinder heads form a V shape, respectively. In a four-cylinder opposed engine (the most common type), the two pistons per side alternately move toward and away from their opposing twins, emulating the fists of opposing boxers — thus the colloquial name “boxer” engine. Its other nicknames, “flat” and “pancake,” reflect the short, wide form these engines take.

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This shape may help give the host vehicle a low center of gravity and/or a low hood line for better aerodynamics. Proponents of the design also claim that the opposed pistons balance each other out, which decreases or eliminates the need for energy-robbing balance shafts: Used in many engines, these rotating, weight-bearing shafts help offset the vibration caused by pistons moving in different planes and/or a less symmetrical fashion.

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Answered by Joe Bruzek on August 18, 2008 in Glossary | Permalink

Comments

hello, can u send me the internal shape of engine( v-shape or cylinder) and the whole its work.tq

these engines are also good because they give you a lot of power and not that much vibrations

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