Four-Stroke Internal-Combustion Engine
The four-stroke (Otto-cycle) engine burns fuel inside the cylinder in a repeating intake–compression–power–exhaust sequence. Its power-to-weight ratio made personal transport and portable power practical.
Attribution — Built up over time by many contributors, often across different regions.
Nikolaus Otto built the first practical four-stroke engine (1876), but the cycle had been described in theory earlier by Alphonse Beau de Rochas, and Étienne Lenoir had built earlier gas engines. Rudolf Diesel later created the distinct compression-ignition engine.
What counts as the invention: The four-stroke cycle (theory: Beau de Rochas) and its first practical engine (Otto) are separate milestones; the diesel engine is a related but distinct invention.
Contributors
Historical impact
Internal combustion enabled the automobile, mechanized agriculture, and portable power generation.
Modern relevance
Otto-cycle engines still power most road vehicles, even as electrification advances.
Sources & further reading
Each citation names the publisher and the exact reference title.
- Encyclopædia Britannica — technology & biography topic articlesEncyclopædia Britannica · Encyclopedia
- Deutsches Museum — collections & researchDeutsches Museum · Museum
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