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A test fleet including 47 gasoline vehicles with 6 different technical types was organized, and the adaptability of these vehicles under China 6 standard was studied. By analyzing the performance of the vehicles tested in laboratory and in real-world, technical types that could simultaneously reconcile emission and fuel consumption performance were proposed. The results show that all vehicles were well performed under laboratory conditions, but in real-world conditions, 50% direct injection vehicles without GPF would fail the RDE test. On the other hand, vehicles with GPF had better performance, all of which passed the RDE tests even if the conformity factor decreased from 2.1 to 1. In addition, it is found that the fuel consumption of the DI vehicles were lower than that of the PFI vehicles. As the DI vehicles with GPF showed better performance on the balance of emission and fuel consumption, indicating that they may have better potentials to deal with the increasing tightened emission and fuel consumption standards at the same time.

A model of fuel system which is with ORVR is established based on STAR CCM +, to study the influence of different refueling velocity on the formation of liquid seal in refueling process. The simulation results show that the increase of refueling rate leads to the formation of liquid seal in the process of fuel flow, but it will lead to the deterioration of refueling smoothness. When the refueling rate is 15L/min, there is no liquid seal formed at the bottom of the refueling pipe, because of the small gas resistance formed in the refueling process, and when the refueling flow rate reaches 37L/min, a stable dynamic liquid seal can be formed at the bottom of the refueling pipe but the fuel accumulation at the refueling port has taken place. When the refueling flow rate reaches40L/min and 45L/min, a stable dynamic liquid seal is formed at the bottom of the refueling pipe at 4s, but until 4 seconds, fuel has been submerged in the refueling muzzle. At 10 seconds, the fuel accumulation state is the same as 5 seconds, indicating that the gun PSO had taken happened.