One of the challenges engineering has to face today is environmental sustainability. It means restrictions of emissions’ standards, as well as consumption reduction to save resources. Moreover, the trend to produce electric power by means of renewable sources (highly aleatory), implies the need for alternative power sources to supply the grid during power lack phases. For this purpose, natural gas fed internal combustion engines have been used in the past. Today, prechamber technology is bringing gas engines back in fashion. To keep the mixture very lean as to reduce fuel consumption is not trivial, as combustion could be incomplete, and the engine could suffer from knock and low power.