Simulation And Study Of The High-pressure Common-rail Injection System Based On HYDSIM

Due to the high pressure of the common-rail injection system, and the fuel atomization is very good, it improve the combustion process greatly, and the fuel injection law can be free,flexible, accurate controlled, so the CR system improve the vehicle economy and the dynamic property of the diesel engine, and reduce the harmful emissions, satisfy the call of "Energy saving and emission reduction". So the CR system will inevitably become the mainstream of fuel system development and application trends.In this paper, the simulation research on solenoid valve dynamic characteristics has been done with SIMULINK model, running to get the valve open response time T1 and closed response time T2, as the input parameters of solenoid valve;In This paper, based on TBD620 single-cylinder engine test bench,established the simulation model of combustion process with AVL BOOST software; With the propulsion characteristics and load characteristics of diesel engine, the fuel injection rate of diesel engine under different loads is obtained,then use MATLAB software to draw a map of the cycle fuel injection quantity.Then established the single-cylinder engine simulation model of common rail fuel injection system with AVL HYDSIM software,compared and analyzed the effects of several system parameters on common-rail pressure oscillation: the pump plunger diameter is bigger,the plunger cavity volume is smaller, the common-rail pipe volume is larger, the ability of the pump oil suppling is stronger, the less common-rail pressure oscillation.Meanwhile, on the basis of a single injector HYDSIM model, under the premise that the fuel injector can work normally,analyzed and researched the influences of several fuel injector structural parameters on injector needle response speed and fuel injection characteristics: control chamber volume is smaller,the inlet orifice diameter is larger,the outlet orifice diameter is smaller, the control piston diameter is larger, the quality of needle valve and control piston is smaller, thee spring preload is bigger, so the response speed of needle is faster and the injection characteristics is better.Finally, with the analysis of the above two parts, the individual parameters are modified,and the optimal design of the whole system is optimized. After the optimization,common-rail pressure oscillations have greatly improved, when fuel injection pressure drop reduces the about 6Mpa, and the pressure average increased 0.8MPa; better response characteristic of needle valve, opening and closing more sensitive, more conducive to precise control; fuel atomization quality is better.