Simulation on the Pressure Control of Common Rail of an In-Cylinder Direct-Injection CNG Engine

Abstract

The paper put forwards and designs high-pressure common-rail fuel injection system based on technology characteristics of in-cylinder and direct-injection compressed natural gas (CNG) engine, and a model of high-pressure common-rail for CNG engine is built with AMEsim software. For researching the dynamic characteristics of high-pressure common-rail system of a CNG engine, the influences of speed, common rail volume, aspect ratio and rail pressure on pressure fluctuation amplitude were synthetically analyzed. At the controlling aim of pressure fluctuation amplitude, a compound controller based on cerebellar model articulation controller(CMAC) neural network and PD is presented and finally the model of control system was built with MATLAB/Simulink. The co-simulation results show that the simulation system can simulate the actual working process of the high-pressure common-rail system for CNG engine and that the used control strategy can meet the demands of flexible control of fuel injection quantity and pressure. Accordingly, the system lays the foundation for researching high-pressure direct injection CNG engine.