According to a novel engine, a device is mounted on an engine of a motor vehicle, a fuel pipe passes through the device, when the engine runs, heat produced by a cylinder block heats fuel in the fuel pipe, molecular structures of the fuel quickly fissure into tiny molecules, then the molecules enter the engine, the fuel can be burnt sufficiently, and then the power of the engine becomes strong and powerful, so that the purpose of saving fuel is achieved, and meanwhile, the environmental pollution is reduced.