They were a success! 1806:
Francois Isaac de Rivaz (born in Paris, December 19, 1752; Died in Sion, July 30, 1828) was a Swiss inventor, credited with inventing and constructing the first successful internal combustion engine in 1806. The engine was powered by a mixture of hydrogen and oxygen. The hydrogen gas was contained in a balloon and the ignition was an electrical Volta starter. A year later, Francois Isaac de Rivaz built one of the first automobiles – of course, powered by his new engine.
NOTE: Gasoline was not used for internal combustion engines until 1870.
https://fuel-efficient-vehicles.org/energy-news/?page_id=819
Video of a water powered car from 1974 https://www.bitchute.com/video/VTbTVVWbwMuq/
Equinox 2 Stanley Meyer, there is a part 1& even a 3rd i believe. This man designed, created, & patent a water powered vehicle. Supposedly poisoned dead & patent dissapeared/ changed..??
https://youtu.be/rvJ3GThSKwE