A boxer engine is an automobile or motorcycle engine that has horizontally opposed cylinders and pistons. They range from the very simple, early Volkswagen Bug with four cylinders and the French Citroen Deux Chevaux on up to the sophisticated Porsche and 12-cylinder Ferrari Testarossa.
Invention of the boxer engine
Inventors had been tinkering around for over two centuries, trying to develop a practical horseless carriage. The first recorded instance is that of a 17th century Jesuit in China, Ferdinand Verbiest, who made a two-foot scale model powered by steam.
Subsequently, several others attempted the feat using steam or batteries; it was not until Karl Benz built his first motor wagen in 1885, receiving a patent for it in 1886, that the automobile was officially invented.
Commercial sales started in 1888, and by 1893, a staggering 25 Benzes were sold. They were three-wheeled vehicles with an in-line engine.
By 1893, Benz introduced a new four-wheeled model with a larger and more powerful engine of his own design. It was a vehicle that would be more affordable.
By 1897, Benz was developing a radically new concept in engines: the "contra engine." This engine, which we know today as the "boxer engine," went into production in 1899 and became the primary power source of all his passenger cars
Even in the earliest days of the motorcar, the need for speed became apparent to Benz, and he sought to develop faster and larger cars. His first engines were all similar, using his early single-cylinder engine design, but soon it became apparent that the boxer concept would be much more powerful and efficient.
By 1898, the 4.2 liter contra engine was ready for deployment and was installed first in buses. By 1899, the engine had been balanced and tuned to eliminate unwanted vibration and noise, thereby extending its lifespan, and it became available in the first four-passenger vehicle.
What are the advantages of the boxer engine?
Having the cylinders directly opposed to each other made for a much more smooth-running motor because each rotation of the crankshaft produced equal forces on opposite sides. While one side was compressing air, the other side was releasing it.
Another great advantage-that it was small, flat and lightweight-would be realized much later, in 1936, when at Hitler's behest, the Volkswagen was designed and built. Volkswagen means "people's car." It was not until after WWII that the Volkswagen Beetle started its historical run, which ended at Mexico's VW plant in Puebla after 22 million Beetles of various models had been produced, all powered by boxer engines.
What other automobiles have use boxer engines?
Some other notable examples of boxer engines being successfully used over long periods include the Citroen 2CV. It featured a 2-cylinder boxer engine, and 8,756,688 of these cars were built between 1948 and 1990. Citroen built assembly plants all over the world, with the last ones being assembled in Portugal.
Another notable brand is Porsche. Its first post-war models were powered with slightly souped-up VW boxer engines. Later, Dr. Ferdinand Porsche and his engineers developed much more powerful versions of their own, eventually graduating to the 6-cylinder Porsche boxer engine that was still in use in 2012.
Chevrolet developed the much-maligned Chevy Corvair, which became subject of a book that made Ralph Nader famous, "Unsafe at Any Speed."
Subaru, Ferrari and Tatra were some of the others who adapted the technology, but perhaps the boxer engine is most famous today for its use as the means of propulsion for BMW motorcycles. Smooth, quiet and long lasting, they have achieved a reputation for reliability that no other motorcycle has been able to match. To the motorcycle connoisseur as well as adventurous travelers of the world on two wheels, there is nothing like a BMW.