PURPOSE: To save fuel and to prevent discharging of noxious exhaust gas, by applying a radioactive element over the inne wall surface of a fuel tank and a water tank, and also applying a radioactive element over the inner wall surface of a combustion chamber of an internal combustion engine.

CONSTITUTION: A radioactive element is applied over the surfaces of a combustion chamber, an intake valve, an exhaust valve, a piston head, etc. of an internal combustion engine. Further, a thin plate of a radioactive element is applied over the entire inner wall surface of a fuel tank and a water tank, and many nets made of the radioactive element and stacked in a multiplicity of layers are disposed in the fuel tank and the water tank. With such an arrangement, fuel and water passed respectively through the fuel tank and the water tank are ionized by the radioactive rays and drawn into the combustion chamber. Therefore, it is enabled not only to save fuel but also to prevent discharging of noxious exhaust gas.