Les moteurs non traditionnels = Motoren nicht konventioneller Art = Non-conventional engines. Paper presented at the 13th FISITA congress, June 8-11, 1970.

This report deals with unconventional type engines for road vehicles; the Stirling engine, the steam engine, the Wankel engine, and the gas-turbine. For each type of engine, an historical note begins by mentioning the essential steps of its evolution. Then follows a general review of their present technical development and a tentative forecast about the future possibilities of these propulsion systems.