Penta engine
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Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

 design, the penta engine (or penta head) is an arrangement of the upper portion of the cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

 and valves that is common in engines using more than two valves per cylinder. It is similar in concept to the hemi engine
Hemi engine
A Hemi engine is an internal combustion engine in which the roof of each cylinder's combustion chambers is of hemispherical form.- History :...

, both in design and raison d'etre, but the hemi is limited to only two valves and thus penta designs tend to be somewhat more efficient.

The four-valve penta engine design was invented by Peugeot of France, to be first used in the 1911 Indianapolis 500 race.

The penta engine (also termed pentroof combustion chamber) is the most common design used today by many manufacturers for four-valve-per-cylinder engines producing relatively high horsepower for displacement, for both racing engines and engines for passenger cars.
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