Turbocharger
Alfred Büchi
Alfred Büchi’s 1905 turbocharger patent established the axial turbine–compressor-on-common-shaft architecture still used today. It solved no immediate problem: the 1915 aircraft prototype failed. Its first functional applications were marine diesel engines in 1923 (1750 → 2500 hp) and stationary diesel engines in 1925 (1,300 → 1,860 kW, +40% efficiency). All verified successes occurred under Büchi’s direct supervision. No verified application existed outside large, slow-speed diesel systems before 1925.