A method and an equipment for reducing emission and fuel consumption in order to improve combustion in internal combustion engines, whereas, in order to achieve perfect combustion, prior to its entry into the combustion chamber of the internal combustion engine, the mixture of fuel and air is led through a treatment area characterized by specific physical properties, so as to provide, by applying high voltage, the air stream a charge of first polarity and the fuel stream a charge of opposite polarity and simultaneously vibrating at least one of the air and the fuel stream by a frequency in the ultrasonic range, in given cases in several, succA method and an equipment for reducing emission and fuel consumption in order to improve combustion in internal combustion engines, whereas, in order to achieve perfect combustion, prior to its entry into the combustion chamber of the internal combustion engine, the mixture of fuel and air is led through a treatment area characterized by specific physical properties, so as to provide, by applying high voltage, the air stream a charge of first polarity and the fuel stream a charge of opposite polarity and simultaneously vibrating at least one of the air and the fuel stream by a frequency in the ultrasonic range, in given cases in several, successive and/or parallel sections.