A vehicle drive system is disclosed comprising an internal combustion engine for driving a vehicle, wherein the internal combustion engine comprises a combustion chamber with injectors for injecting diesel into the combustion chamber, a supply line for delivering a gas mixture to the combustion chamber, an electrolysis chamber for producing hydrogen gas and oxygen gas, and a vacuum pump for sucking the hydrogen gas and the oxygen gas from the electrolysis chamber. The vehicle drive system furthermore comprises a gasification tank with volatile organic compounds received therein, in particular methanol or ethanol, as well as a supply line for supplying a gas mixture to the combustion chamber, wherein the gas mixture comprises gasified organic compounds from the gasification tank and at least a part of the hydrogen gas and the oxygen gas. Furthermore a corresponding method for operation a vehicle drive system is disclosed.