Study On The Multidisciplinary Design Optimization (MDO) And The Intelligent Control (IC) On The High Pressure Common Rail Fuel Injection System

The clean, energy-saving and Environment-protection diesel engine, with electronically controlled high pressure common-rail fuel injection system,will be the main driving force in the field of transportation in the 21st century, and has become the inevitable trend of development in the field of automotive power. The overall optimal design of diesel engine high-pressure common rail fuel injection system, the coordination mechanism of multiple injection and the intelligent control strategy of common rail system have very important practical significance to enhance the stability of common rail system, improve the accuracy of injecting fuel, optimize the overall performance of the engine and reduce the pollution and save the energy.Based on National"863"Program(2008AA11A116)"Manufacture of High Efficiency & Low Emission Diesel"and the "985" second stage of Hunan University——the innovation platform of science and technology of automotive design and manufacture (thesub-project of power emission and electric control) (Education accented term [2004] No. 1) , with the method of combining theoretical analysis with experimental study, the goal of the paper is to improve the stability of high-pressure common rail fuel injection system and make the diesel engine's power and economy better and also to reduce the emissions. This paper's main work and innovative points are as follows:(1) For the complex issues of MDO for the high pressure common rail fuel injection system, the paper establishes the basic physics - mathematical models of the high pressure common-rail fuel injection system and the basic framework of MDO for distributed parallel of high-pressure common rail fuel injection system, it provides a strong theoretical support for MDO for the high pressure common rail injection system.(2)Combining quantum computing, chaos theory with the theory of genetic algorithms, the paper uses the chaos model of infinite fold frequency to produce chaotic variables and proposes a novel optimization algorithm——adaptive mutative scale chaos quantum genetic algorithm to provide a solid technical support for MDO and IC for the high pressure common rail injection system.(3)This paper takes the oil-pumping performance , the pressure fluctuation performance, spray performance and mass of the high-pressure common rail fuel injection system as the target function and takes the multiple conditions such as geometry, structure, and the state of the high pressure common rail fuel injection system as the constraints in order to study the overall optimization of the high pressure common rail fuel injection system systematically , the results show that the pumping performanceηof the high pressure common rail fuel injection system is increased by 16.7%, pressure lossΔp is decreased by 18.9%,mass M is decreased by 14.7%, atomization performance Vi is enhanced 6.2%, and the overall performance U is increased by 9.5%.(4)Considering of environmental and electrical control system factors comprehensively, based on a hierarchical design methodology, the paper designs the control algorithm for the key components of environment layer, constraint layer and set layer etc, and establishes a single-condition multiple injection dynamic combination model and multi-condition repeated injection dynamic combination model with LS-SVM, and it has verified the correction of the multiple injection dynamic coordinated control strategy.(5)Based on the determination of the set value of the high pressure common rail pressure, nonlinear intelligent correction of high pressure common rail pressure sensor and intelligent optimization correction of diesel fuel consumption measurement model and other measures, the paper proposes a combination control strategy of neurons of high pressure common rail pressure and integration of fuzzy reasoning. Simulation and experimental results show that the fluctuation of common rail pressure control curve is relatively stable and fluctuation is less than 4MPa.With the visualization spray combustion test equipments, the paper carries on the process experiment of spray combustion before and after improving for the high pressure common rail fuel injection system and comparative analysis of spray development map, the results show that: the improved high-pressure common-rail fuel injection system has better atomization performance, the main combustion period is shorter and its spray combustion performance is improved significantly.