Bingqi Tian

A study on cycle fuel injection quantity variation for a diesel engine combination electronic unit pump system

A new fuel injection equipment, combination electronic unit pump was developed to make diesel engines compliant with China’s new laws on emissions. Combination electronic unit pump system is a complex assembly constituting of mechanical, hydraulic, and electrical magnetic components. Combination electronic unit pump system includes several electronic unit pumps and mechanical injectors. Cycle fuel injection quantity variation influences product performance and defines its quality of qualification. A numerical model of the combination electronic unit pump system was developed in AMESim environment to create a design tool for engine application and system optimization. Simulated results obtained from this numerical model were validated through experimental tests conducted under the conditions same as numerical model. The results are quite encouraging and consistent with model predictions. Influences of parameters, including variations in supply fuel pressure, cam velocity, plunger-matching clearance, peak control current, anchor residual clearance, valve-matching clearance, valve lift, injector opening pressure, nozzle-flow coefficient, and injector needle lift, on cycle fuel injection quantity variation were analyzed in AMESim simulation environment and verified through experiments. The quantitative percentage indexes of the influence of injector characteristic, valve characteristic, plunger characteristic, and low-pressure supply fuel characteristic parameters on cycle fuel injection quantity variation range from 44% to 34%, 20% to 35%, 32% to 19%, and 4% to 12%, respectively, at a cam rotational speed of 500–1300 r/min.

Nonlinear Modeling and Analysis of Pressure Wave inside CEUP Fuel Pipeline

Operating conditions dependent large pressure variations are one of the working characteristics of combination electronic unit pump (CEUP) fuel injection system for diesel engines. We propose a precise and accurate nonlinear numerical model of pressure inside HP fuel pipeline of CEUP using wave equation (WE) including both viscous and frequency dependent frictions. We have proved that developed hyperbolic approximation gives more realistic description of pressure wave as compared to classical viscous damped wave equation. Frictional effects of various frequencies on pressure wave have been averaged out across valid frequencies to represent the combined effect of all frequencies on pressure wave. Dynamic variations of key fuel properties including density, acoustic wave speed, and bulk modulus with varying pressures have also been incorporated. Based on developed model we present analysis on effect of fuel pipeline length on pressure wave propagation and variation of key fuel properties with both conventional diesel and alternate fuel rapeseed methyl ester (RME) for CEUP pipeline.

Study of Fuel Injection Quantity Fluctuation of High Pressure Common Rail System with Electronic Control

High pressure common rail (HPCR) injection system not only enables the diesel engine to meet the increasingly strict emission criterion, but also enhances its economic efficiency and comfort ability. Its simulation model is established in AMESim environment and it is calibrated to ensure the accuracy. The influences to cycle fuel injection quantity (CFIQ) of electromagnetic valve lift, control piston clearance, needle valve lift, open pressure and flow coefficient are analyzed in details with the simulation model in the whole working conditions. The results show that electromagnetic valve lift, needle valve lift, open pressure and flow coefficient are the key characteristic parameters on fuel injection quantity fluctuation (CFIQF).

Study on Injection Characteristics of Small Injection Quantity for Common Rail Fuel Injection System

Electronic high pressure common rail fuel injection system simulation model is established in AMESim environment. By comparing with experiment, the simulation model can accurately predict injection characteristics of the electronic high pressure common rail fuel injection system. The influence of the parameters such as pre-tightening force of solenoid, control valve lift, diameter of outlet hole, diameter of inlet hole, pre-tightening force of needle, needle lift and nozzle flow coefficient on the fuel injection characteristics is analyzed in details with the simulation model. The influence law and generation mechanism of influence of injection characteristics caused by variations of characteristic parameters were revealed. The results show that control valve lift, diameter of outlet hole, diameter of inlet hole and nozzle flow coefficient are the key characteristic parameters of the fuel injection characteristics.

Study of quantity characteristics of double valves fuel injection system with electronically controlled

Double valves system simulation model is established in AMESim environment, By comparing with experiment, The simulation model can accurately predict injection characteristics of the double valves system. The influence of the parameters such as piston diameter, cam velocity, piston matching clearance, SV valve lift, NCV valve lift, needle valve lift and injector diameter on the main fuel injection quantity fluctuation is analyzed in details with the simulation model in the whole working conditions The change rule of the main injection quantity fluctuation with speed and injection pulse is obtained under different parameters, The results show that piston diameter, cam velocity and injector diameter are the key characteristic parameters on the main fuel injection quantity fluctuation.