Evaluation of hydrogen and oxygen mixture addition in internal combustion engines under real driving conditions

The addition of a hydrogen and oxygen mixture (HHO) into internal combustion engines is often associated with expectations of oticeable increases in engine performance and substantial reductions in emissions and fuel consumption. This paper investigates the actual effects of introducing hydrogen and oxygen into combustion engines. A literature review was conducted, identifying several research gaps in this field. An improved experimental methodology was developed to quantify the effects of hydrogen and oxygen addition while minimizing the influence of external factors on the results. Measurements were carried out using three vehicles. Two of the vehicles were identical and operated for 67,000 km under the exact same conditions, with only one of them equipped with an HHO generator. The results of the measurements, discussed in the context of other scientific publications, indicate that HHO addition produced no measurable improvement in engine power or torque, and only minor changes in exhaust gas composition. These findings demonstrate that the benefits of HHO addition are significantly lower than those claimed by commercial providers. This study provides evidence-based insight into the limited practical impact of HHO on vehicle performance and emissions, helping to inform sustainable mobility solutions.