Der (ungerade) Collatz-Baum

The invention relates to a thermal engine provided with inlet and exhaust valves and with a system for controlling said engine comprising a computer which regulates opening and closure of said valves and which imposes on said engine an operation close to the one corresponding to minimum specific fuel consumption. According to the invention, this assembly is characterized in that said engine is essentially of the four-stroke cycle type, in that said system comprises means adapted to detect overloads of the engine and means adapted to cause the engine to operate exceptionally in two-stroke mode, these latter means being actuated by said detection means when the detected overload exceeds a predetermined threshold so that in that case the engine passes to two-stroke operation, four-stroke operation being resumed as soon as the overload has disappeared. The invention leads to obtaining a low consumption of fuel for increased power.