
The original sketch of da Vinci engine (1508), above center, an upside-down cannon barrel fitted with a piston, as sketched by Leonardo Da Vinci (1508), along with a clearer visual of his design at right, which operates such that when the gunpowder is exploded above the piston, the explosive combustion creates a vacuum, in the area above the piston, which causes the surrounding atmosphere to push the bottom of the piston upward, thereby lifting the attached weight. [1]

The original sketch of da Vinci engine (1508), above center, an upside-down cannon barrel fitted with a piston, as sketched by Leonardo Da Vinci (1508), along with a clearer visual of his design at right, which operates such that when the gunpowder is exploded above the piston, the explosive combustion creates a vacuum, in the area above the piston, which causes the surrounding atmosphere to push the bottom of the piston upward, thereby lifting the attached weight. [1]

In engines, Da Vinci engine refers to []

Overview
In 1508, Leonardo da Vinci, in his notes of his folio 16v of MS F, sketched a gunpowder engine, shown adjacent at center.

At left, is rendition of da Vinci's engine (Needham, 1987), showing a cannon barrel fitted with a closable lid, and a exhaust fumes release valve, which operates such that when gunpowder is placed on the piston and ignited, an explosion occurs, the reactant vapors leave through the release valve, and a vacuum is thus created inside the piston and cylinder, thereby acting to make the piston rise in the cylinder, lifting weight, by the force of atmospheric pressure. [2] That diagram at right shows a thicker cannon barrel like design, which seems closer to what da Vinci envisioned.

Da Vinci described his engine as follows:

“A mechanism to lift heavy weights. To lift a heavy weight with fire, like a cupping glass. And the vessel should be one braccio [about 2 feet] wide and ten long, and should be strong. It should be lit from below like a bombard (Ѻ) and the touchhole rapidly and immediately closed on top. The bottom, that has a very strong leather, like a bellow, will rise and this is the way to lift any heavy weight.”
— Leonardo da Vinci (1508), “note on device to lift heavy weight with fire”, Folio 16v of MS F [1]

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Quotes
The following are related quotes:

“The only detail that differentiates Leonardo’s machine from those of Huygens and Papin is the system adopted for raising the weight sustained by the piston. Huygens and Papin use a pulley and rope transmission (the same that Leonardo adopted in his experiments with steam), while Leonardo preferred to attach a rod to the bottom of the piston.”
— Ladislao Reti (1969), “Leonardo da Vinci the Technologist: the Problem of Prime Movers” [17]

References
1. (a) Da Vinci, Leonardo. (1508). “Cannon-barrel gunpowder engine”, Folio 16v of MS F.
(b) Da Vinci, Leonardo. (1508). “Title”, mod auct. Seq. Ret. Codex F (Institute of France), 1v; cf. Codex Atlanticus, 5, r.a., 7 r.a.
(c) Hart, I.B. (1961). The World of Leonardo da Vinci: Man of Science, Engineer, and Dreamer of Flight (with a note on Leonardo’s helicopter model by C.H. Gibbs-Smith) (pg. 299). McDonald.
2. Needham, Joseph. (1987). Science and Civilization in China: Volume 5, Chemistry and Chemical Technology, Part 7, Military Technology: The Gunpowder Epic (§§: Gunpowder as the Fourth Force: its Role in the History of Steam Engines, pgs. 544-67; Da Vinci, pgs. 552-563). Cambridge.