A 1905 patent that worked on paper—but only delivered real power nineteen years later, and only in ships and locomotives, never in the planes it was built for.
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.
1905 is the birth year—not because it worked, but because Büchi defined the core architecture still used today.
2:13
The Failed Flight
The first target was aircraft engines at altitude—but the 1915 prototype failed reliability testing and never flew.
3:22
First Real Power
Commercial use began not in aviation, but in 1923 marine engines—where Büchi’s turbochargers lifted output from 1750 to 2500 hp.
4:49
The Diesel Breakthrough
In 1925, Büchi proved turbocharging could raise diesel efficiency by over 40%—a gain verified on ten-cylinder engines delivering 1,300 → 1,860 kW.
6:03
How It Actually Works
The mechanism is fixed: exhaust heat spins a turbine, which drives a compressor on the same shaft, forcing more air into cylinders.
7:16
Where It Succeeded—and Where It Didn’t
Every verified success came under Büchi’s supervision, on large, slow-speed diesels—never on petrol engines, small units, or aircraft.
3 more chaptersFewer chapters
Worth your time?
Yes. Study the whole thing.
4/ 5
What works
recovers exhaust heat as mechanical compression
raises diesel power density
improves diesel efficiency by over 40%
enables larger power output without larger displacement
What does not
solve aircraft altitude power loss
work in 1915
apply to petrol engines before 1925
achieve commercial use before 1924
Study it if
marine diesel engineers
locomotive designers
historians of thermodynamic recovery
Skip it if
aviation engineers seeking early solutions
automotive developers before the 1930s
anyone expecting immediate deployment
Who should study it, and who should skipHide who it is for
The written brief1 min read
What it is and the problem it solves
It is an exhaust-gas-driven forced induction system. It solves the problem of falling engine power output caused by low air density at altitude—and later, the inefficiency of large diesel engines at part load.
How it works
It uses an exhaust-driven axial turbine and axial compressor on a common shaft. The turbine captures heat from engine exhaust gas. That rotation forces additional air into the cylinders via the compressor.
What works
It works on large marine and stationary diesel engines. In 1923, Büchi’s turbochargers boosted twin ten-cylinder marine diesel output from 1750 to 2500 hp. In 1925, they increased ten-cylinder diesel power from 1,300 to 1,860 kW and raised efficiency by over 40%.
What does not
It does not solve altitude-related aircraft engine power loss in practice. The 1915 prototype was unreliable and never entered production.
What it changes
It changes how internal combustion engines recover waste energy. Exhaust heat—previously discarded—is mechanically converted into intake air compression. This enables higher power density and efficiency without increasing engine displacement.
Is it worth your time
Yes—if you work on diesel power systems, marine propulsion, or high-altitude engine design. Its mechanism remains foundational, but its 1915 aircraft application failed, and commercial viability took 19 years to prove.
