Common engine architectures include the V-type and incline engines, but the most unique of the three is the horizontally opposed engine. The horizontally opposed engine, also known as the boxer engine, is the only engine that has pistons that move from side-to-side and give the engine a flat look. The boxer engine has an uneventful past, a rich present and bright future.
The original design for the boxer engine comes from Carl Benz in 1896 (Hendriks, 2006). The concept for the engine was scarcely used until just between the two world wars. The boxer twin started off being produced for motorcycles by companies like BMW, CZ, Harley and Honda. Shortly after World War II, Ferdinand Porsche released the KDF (the original VW Beetle), which was based on the NSU and Mercedes Benz prototype. Common cars that used the flat engine design were: The Chevrolet Corvair, Porsche 914, Porsche 911 and the Subaru Impreza (Hendriks, 2006).
The flat engine was first used in motorcycles during the time of World War II. In 1923 BMW released its first motorcycle, the R32, with a horizontally opposed twin-cylinder engine (BMW Motorrad, para 2). This engine architecture was used by many motorcycles after the R32’s release. In fact, many aircraft still use a horizontally opposed engine to power their propellers.
One of the most spectacular things about the boxer engine is its design. Unlike any other internal combustion engine, the pistons lie horizontally opposed with the cylinders on the left and right side of the block. This allows boxer engines to run perfectly smooth and free of vibrations with a four-stroke cycle, regardless of how many cylinders it may have. Considering all of this, the balance of the flat engine is what has made it so popular amongst sports cars. Each piston’s movement is exactly counterbalanced by the corresponding piston movement of the opposite side (Subaru of America, 2012). Since the engine is low and wide
References: Hendriks, H. (May 2006). The history of the flat or boxer engine. Tales of Toy Cars.