To solve problems in the environmental pollution by exhaust gas, by reacting the total of the heat of compression of the air, and the heat of explosion of the fuel, with the injected water to be vaporized, and outputting the total energy of the pressure energy by the explosion of the fuel and that by the vaporization of the water, as a power driving source.

A fuel supply system 2 comprises a conduit 22 for supplying the fuel in a fuel tank, to a combustion chamber 15, and a carbureter 23, and the injection of the fuel to the combustion chamber 15 is related 24 to the rotation of a crank 14, and is performed through a command 25 just before the completion of the air compression stroke or at the completion of the same. Further a water supply system 3 comprises a conduit 32 for supplying the water in a water tank 31, to the combustion chamber 15, and an atomizer 33, and the injection of the water to the combustion chamber 15 is related to the injection time of the fuel, and is performed through a command 35 just before or immediately after the completion of the explosion. The pressure in the combustion chamber 15 is expanded by the synergistic effect of the rise of the pressure by the explosion of the fuel, and the rise of the pressure by the vaporization of the water, and the huge pressure energy is generated.