The present invention is a system for increasing the fuel efficiency of a vehicle of the type having an internal combustion engine, a battery, a vacuum line, and a fuel line that feeds fuel to the engine. The system comprises a hydrogen gas generator and a vacuum regulator. A vacuum regulator is in fluid communication with the vacuum line of the vehicle and an output line of the gas generator. The vacuum regulator includes a vacuum pressure adjustment means for controlling the amount of hydrogen gas that is introduced into the vacuum line of the vehicle. In use, hydrogen gas is introduced into the vehicle vacuum line and then into the engine where it is mixed with the fuel from the fuel line and ambient air. The hydrogen gas increases the atomization of the fuel for more efficient burning thereof in the engine. A fuel additive including an acetone-based compound, a xylene-based compound, and an upper cylinder lubricant may be mixed with the hydrogen gas to further atomize the fuel. An oxygen sensor signal generator that generates a bypass signal replicates the output of a vehicle oxygen sensor under normal operating conductions to keep the air mixture of the engine unaffected. The system may additional include at least one fuel heating means fixed to a high-temperature portion of the engine, such that the fuel is heated before being introduced into the engine so as to further increase atomization of the fuel for more efficient burning thereof in the engine.