Abstract: This paper analyzes the standards of the test methods of fuel consumption of conventional and hybrid passenger cars. Based on the validity and applicability of the standards and other relevant standards at home and abroad, this paper puts forward the suggestion that the 48 V vehicles should be classified as hybrid electric vehicles. In order to carry on the fuel consumption experimental research, four mainstream 48 V models in our country are selected. Firstly, energy-saving of the 48 V system is theoretically analyzed according to the operating characteristics of the engine and the motor and the power output / input of the power system during the test. According to the test results of the four models, it can be concluded that the 48 V system can reduce the vehicle fuel consumption by 0.47 L/100km, which is equivalent to fuel saving of 6.48%

Key words: 48 V vehicle, fuel consumption, standard, test