Investigation On Injection Pressure Rise Rate Characteristics Of Unit Pump Fuel System With Electronically Controlled

Electronic unit pump (EUP) is electronic fuel injection system which makes dieselengine meet the current economy demand of fuel and emissions regulations. Injectionpressure is the key factor to match a diesel engine successfully, which determines the amountof oil and fuel atomization quality. Injection pressure rise rate determines the establishmentand discharge of injection pressure on the dynamic response of the process. Studying thecharacteristics of injection pressure rise rate on the EUP in all conditions will be concludedthe key characteristic parameters affecting injection pressure rise rate, which is meaningful forthe optimization of EUP injection system and the improvement of its performance.This paper adopts the experiment and numerical simulation method combined to studyinjection pressure characteristics of EUP fuel system through the establishment of Electricunit pump test-bed and AMESim numerical model. First of all, study on all conditions ofinjection pressure rise rate characteristics that is concluded the rules of the differentparameters influencing injection pressure rise rate in all conditions. Cam contour line rate,plunger diameter, high-pressure oil pipe length, high-pressure oil pipe diameter, needle-valvespring pre-tightening force and the orifice discharge coefficient are the key influenceparameters on the injection pressure mean pressure rise rate and instantaneous pressure riserate, maximum pressure rise rate and the minimum pressure rise rate.Later, study on the quantitative analysis of injection pressure rise rate in the whole rangeof working conditions, it is concluded the percentage of the quantitative indicators of six keyinfluence parameters on the average pressure rise rate, maximum pressure rise rate and theminimum pressure rise rate. Finally, the application of test design thought, the correlationanalysis on the average pressure rise rate, maximum pressure rise rate and the minimumpressure rise rate adopting the surface central composite design of response surface methodthat is to study the varying rules on the six key parameters under the condition of theinteraction of the secondary factor with the correlation of pressure rise rate. The predictionmodel of the average pressure rise rate is fitted out by using the partial least squares, which isto provide theory support for the prediction of injection pressure rise rate on EUP.