In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a turbocharger is powered by the kinetic energy of the exhaust gases, whereas a supercharger is mechanically powered (usually by a belt from the engine's crankshaft). However, up until the mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. History Prior to the invention of the turbocharger, forced induction was only possible using mechanically-powered superchargers. Use of superchargers began in 1878, when several supercharged two-stroke gas engines were built using a design by Scottish engineer Dugald Clerk. Then in 1885, Gottlieb Daimler patented the technique of using a gear-driven pump to force air into an internal combustion engine. The 1905 patent by Alfred Büchi, a Swiss engineer working at Sulzer is often considered the birth of the turbocharger. This patent was for a compound radial engine with an exhaust-driven axial flow turbine and compressor mounted on a common shaft. The first prototype was finished in 1915 with the aim of overcoming the power loss experienced by aircraft engines due to the decreased density of air at high altitudes. However, the prototype was not reliable and did not reach production. Another early patent for turbochargers was applied for in 1916 by French steam turbine inventor Auguste Rateau, for their intended use on the Renault engines used by French fighter planes. Separately, testing in 1917 by the National Advisory Committee for Aeronautics (NACA) and Sanford Alexander Moss showed that a turbocharger could enable an engine to avoid any power loss (compared with the power produced at sea level) at an altitude of up to above sea level. The testing was conducted at Pikes Peak in the United States using the Liberty L-12 aircraft engine. The first commercial application of a turbocharger was in 1925, when Alfred Büchi successfully installed turbochargers on ten-cylinder diesel engines, increasing the power output from . This engine was used by the German Ministry of Transport for two large passenger ships called the Preussen and . The design was licensed to several manufacturers and turbochargers began to be used in marine, railcar and large stationary applications. Turbochargers