Hydrogen Internal Combustion

Hydrogen internal combustion engine cars are different from hydrogen fuel cell cars. The hydrogen internal combustion car is a slightly modified version of the traditional gasoline internal combustion engine car. These hydrogen engines burn fuel in the same manner that gasoline engines do.
Francois Isaac de Rivaz designed in 1807 the first internal combustion engine on hydrogen Paul Dieges patented In 1970 a modification to internal combustion engines which allowed a gasoline powered engine to run on hydrogen US patent 3844262.
Mazda has developed Wankel engines that burn hydrogen. However the major car companies such as Daimler Chrysler and General Motors are investing in the more efficient hydrogen fuel cells instead.
From Wikipedia