This is an efficient fuel-saving product based on the resonance principle, which is an external energysaving device customized for logistics companies, transportation fleets, and individual vehicle owners. The product is designed to address the issues of improving engine thermal efficiency and reducing fuel losses. Based on the principles of wave and resonance, a pulse technology and self-vector resetting technology are proposed to improve the combustion efficiency. Mainstream brand vehicle tests have shown that the fuel efficiency of various brand vehicles has been effectively improved (6.15%～11.16%) in the testing range of 1500～3500 km, with the highest reaching 11.16% and the highest fuel saving per 100 kilometers being 3.29 liters. At the same time, theoretical analysis based on the design principle shows that the fuel-saving efficiency will gradually improve and eventually reach a stable optimum value after a certain adaptation period.