Studing On Dynamic Characteristics Of Double-valve Electronic Unit Pump Fuel Injection System

The double-valve EUP(Electronic Unit Pump)is a complex fuel injection system containing the mechanical,fluid and electromagnetic parts which are mutually coupled.From controlling the fuel injection process through the synergistic actions of two electromagnetic valves.Therefore,the dynamic characteristics of the valves are not only determinant for the accuracy of the fuel feeding and injection,but also affect the injection pressure fluctuation which decide the fuel injection performance of the double-valve EUP.The dynamic characteristics of the system affect the factors such as pressure,timing and quantity of the fuel injection.In this paper,the dynamic response characteristics of the electromagnetic valves and fuel injection pressure was deeply studied.At first,A numerical simulation model under the AMESim environment of the fuel injection system of the double-valve EUP was established in this paper.A methodology that uses the experiment data to demonstrate the correctness of the numerical simulation model has employed to study the dynamic properties of the system.Then,two structural parameters of the electromagnetic valve was studied and the dynamic delay rules caused by the parameters in the ups and downs of the electromagnetic valve shaft were validated.Then,the dynamic characteristics of the fuel injection pressure was considered in all range of the operating conditions.The analysis of the structure parameters and controlled variables reveal their effect on the pressure rise rate of single fuel injection and twice fuel injection consisting of the pilot injection and main injection and the pressure drop rate during the main injection.At last,the affect laws of the structure and control parameters on the working properties of the system are unearthed,to support the design works of the double-valve EUP,theoretically.