Who built the first successful internal combustion engine?

Étienne Lenoir built the first practical internal-combustion engine. Patented in 1860, his two-stroke engine burned a mixture of coal gas and air inside the cylinder and ignited it with an electric spark.

That internal combustion principle differed from a steam engine, where fuel burns outside the working cylinder to heat water. Lenoir adapted the general form of a steam engine but replaced steam pressure with expanding combustion gases. His design was inefficient, yet it worked reliably enough to be manufactured and sold.

Lenoir’s engine powered machinery and later a rudimentary vehicle. In 1863, his Hippomobile reportedly traveled about 18 kilometers from Paris to Joinville-le-Pont in roughly three hours. The engine’s low efficiency limited its long-term success.

Nikolaus Otto and Eugen Langen later produced a more efficient and commercially successful atmospheric engine, and Otto’s four-stroke cycle became foundational for modern gasoline engines. That later achievement does not erase Lenoir’s priority as the builder of the first practical engine of this type.