Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 130,253 pages of information and 205,637 images on early companies, their products and the people who designed and built them.
of Julius Hock & Co of Vienna
1873 Julius Hock patented an internal combustion engine using volatile petroleum as fuel and having flame ignition. Built for a limited period, Lyle Cummins stated that its unreliability and danger, plus the introduction of the Otto 4-stroke cycle 'quickly ended its tenuous existence'. 
Hock & Co also produced hot air engines in Vienna. An example is on display in Vienna Technical Museum.