Quantitative Analysis On Cycle Fuel Injection Quantity Variation Of The Electronic Unit Pump Fuel Injection System In Overall Operating Conditions

Electronic unit pump (EUP) is a time controlled fuel injection system which could satisfy emission legislation and fuel economy of the diesel engines. Cycle fuel injection quantity variation of EUP has influence on both of the stability and the coherence of the system. It is of great significance in optimizing and improving coherence of the EUP system to figure out the key parameters which influence the stability of cycle fuel injection quantity variation by analyzing the characteristic of cycle fuel injection quantity variation in overall operation condition of the EUP.The simulation model of EUP was established in the AMESim environment based on the WP2000 electronic combination pump fuel injection system. The model was calibrated by experiment data and the accuracy of the model also has been validated, the error of the model is less than 6.6%. The calibrated model could meet the requirement of analyzing on the EUP system.The quantitative percentage index of the influence of different parameters on cycle injection quantity variation was obtained by quantitatively analyzing. Fuel supply pressure, cam profile velocity, control valve lift, injector opening pressure and injector flow coefficient are the six key parameters which have obviously influence on cycle injection quantity stability.For correlation analyzing, the method of simulation experiment was designed by using the Design of Experiments (DOE) method in the MODDE environment. The variation law of correlation between different parameters and cycle injection quantity variation under parameters interaction or not in the overall operating conditions was revealed respectively. The result shows that the EUP system is a complex nonlinear system. The parameters such as fuel supply pressure, cam profile velocity, control valve lift, injector opening pressure, injector needle lift and injector flow coefficient have most significant correlation with the cycle fuel injection quantity. The second order factors under self interaction of parameters are the most remarkable second order factors and the second order factors under interaction of cam profile velocity and other parameters are secondary influence factors of the cycle fuel injection quantity.