NOVELTY - The method comprises producing energy through a regenerative braking device, utilizing the produced energy in an electrolysis device for the partial electrolysis of electrolytes containing water into hydrogen and oxygen, intermediately storing the produced hydrogen and oxygen in supply containers, and dosing the produced hydrogen and oxygen to combustion fuel-air-mixture in combustion chambers of combustion engine (1). The electrolysis device comprises a ring-core transformer for producing a high frequency high voltage field.    USE - Method useful for reducing fuel consumption in combustion engine of vehicle.    ADVANTAGE - The method ensures simple and efficient reduction of fuel consumption in combustion engines and increases the power of vehicles.    DETAILED DESCRIPTION - The method comprises producing energy through a regenerative braking device, utilizing the produced energy in an electrolysis device for the partial electrolysis of electrolytes containing water into hydrogen and oxygen, intermediately storing the produced hydrogen and oxygen in supply containers, and dosing the produced hydrogen and oxygen to combustion fuel-air-mixture in combustion chambers of combustion engine (1). The electrolysis device comprises a ring-core transformer for producing a high frequency high voltage field. The regenerative braking device consists of electric machines operated as generators, where the electric machines are connected with wheel of non-combustion motor drive axis to be braked. The energy is produced additionally or alternatively to the regenerative braking device by solar cells. The hydrogen and oxygen are intermediately stored in stochiometric mixture in common container under high pressure. The dosing of the produced hydrogen and oxygen is carried out in constant quantity or in quantity dependent upon the number of motor revolutions. The excess energy produced in the regenerative braking device and/or the solar cell is used for loading a buffer accumulator. The energy production is supervised by a system that undertakes an energy supply from the buffer accumulator and/or the accumulator (13) of the combustion engine into the electrolysis device, when the energy quantity falls short of the energy quantity required for sufficient electrolysis. The water is filled to the electrolysis device by a condenser (18) that condenses humidity, and/or the condensate outlet of air-conditioner of the vehicle and/or a rain water collection device. An INDEPENDENT CLAIM is included for a device in a vehicle for reducing fuel consumption in combustion engines.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a vehicle with a device for reducing fuel consumption.    Combustion engine (1)    Drive (2)    Electrolysis cell (9)    Accumulator (13)    Condenser. (18)