What did Etienne Lenoir invent?

Etienne Lenoir invented the first commercially successful internal combustion engine.

This engine, which he patented in 1860, ran on illuminating gas (a mixture of gases, primarily hydrogen and methane) and was used to power a small, single-cylinder vehicle called a "Lenoir engine."

While the Lenoir engine was not very efficient and had a limited range, it was a significant step forward in the development of the internal combustion engine.