Alphonse Beau de Rochas
Alphonse Beau de Rochas was a French engineer who described the operating principles of the four-stroke internal-combustion engine in 1862.
Four-stroke engine: An internal-combustion engine cycle with intake, compression, power, and exhaust strokes completed over two crankshaft revolutions. Beau de Rochas set out the principles behind this engine cycle.
Intake stroke: The phase in which an engine cylinder draws in fresh air or a fuel–air mixture. It begins the four-stroke sequence he described.
1862: A year in the nineteenth century, preceding the widespread development of practical four-stroke engines. Beau de Rochas published his engine principles in this year.
Nikolaus August Otto: A German engineer best known for developing a practical four-stroke internal-combustion engine. Otto's engine made the cycle associated with Beau de Rochas a working technology.
Two-stroke engine: An internal-combustion engine that completes its operating cycle in two piston strokes. It accomplishes intake, compression, power, and exhaust with fewer strokes than the cycle he described.
Nikolaus Otto: A German engineer who developed and commercialized a successful four-stroke gas engine in the 1870s. Otto later built a working engine using principles similar to those Beau de Rochas had described.
Compression stroke: The phase in which a piston compresses the cylinder's trapped charge before combustion. Compression is one of the distinct stages in his engine cycle.
Étienne Lenoir: A Belgian-born inventor whose commercial gas engine, introduced in 1860, operated without the four-stroke cycle. Lenoir's earlier engine provides a practical predecessor to the principles Beau de Rochas proposed.
Alphonse Eugène Beau: The French engineer commonly known as Alphonse Beau de Rochas, who described a four-stroke engine cycle in 1862. This expanded name identifies the same engineer behind the familiar shortened form.
Diesel cycle: An idealized thermodynamic cycle in which heat is added at constant pressure. It models compression-ignition engines rather than the spark-ignition cycle most associated with Beau de Rochas's principles.