- 1860: Belgian Jean Joseph Etienne Lenoir (1822–1900) produced a gas-fired internal combustion engine similar in appearance to a horizontal double-acting steam beam engine, with cylinders, pistons, connecting rods, and flywheel in which the gas essentially took the place of the steam. This was the first internal combustion engine to be produced in numbers.
- 1861 The earliest confirmed patent of the 4-cycle engine, by Alphonse Beau de Rochas. A year earlier, Christian Reithmann made an engine which may have been the same, but it's unknown since he didn't clearly patent it.
- 1862: German inventor Nikolaus Otto was the first to build and sell the engine. He designed an indirect-acting free-piston compressionless engine whose greater efficiency won the support of Eugen Langen and then most of the market, which at that time was mostly for small stationary engines fueled by lighting gas.
- 1870: In Vienna, Siegfried Marcus put the first mobile gasoline engine on a handcart.
- 1876: Nikolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, improved the four-cycle engine. The German courts, however, did not hold his patent to cover all in-cylinder compression engines or even the four-stroke cycle, and after this decision, in-cylinder compression became universal.
- 1878 Dugald Clerk designed the first two-stroke engine. He patented it in England in 1881.
- 1879: Karl Benz, working independently, was granted a patent for his internal combustion engine, a reliable two-stroke gas engine, based on the same technology as De Rochas's design of the four-stroke engine. Later, Benz designed and built his own four-stroke engine that was used in his automobiles, which were developed in 1885, patented in 1886, and became the first automobiles in production.
- 1882: James Atkinson invented the Atkinson cycle engine. Atkinson’s engine had one power phase per revolution together with different intake and expansion volumes, making it more efficient than the Otto cycle.