Ion current feedback extreme regulation of cycle fuel supply in the IC engine

The article is focused on the development of ion current feedback based adaptive control methods for internal combustion engine (ICE). A brief overview of the methods of the air / fuel ratio regulation and the purpose of the research are given. The aim of the research is to develop a problem-oriented model of the integrated characteristic of the ion current signal and an extreme regulation system for cyclic fuel supply based on it, capable of enabling the engine to function at a predetermined air / fuel ratio under conditions of parametric uncertainty in the control object. Based on the analysis of the work of third-party authors, as well as experimental studies, the possibility of using the ion current signal in the fuel management systems of an ICE is proved to solve the problem of maintaining a given air / fuel ratio by the principle of extreme regulation. The functional dependences of the integrated characteristic of the ion current signal vs. excess air coefficient for various IC engine operating modes have been obtained using approximation of the experimental data. Based on the dependencies above and the transfer functions, the problem-oriented mathematical model of the integrated characteristic of the ion current signal was developed and verified. The developed mathematical model with effect of the excess air factor takes into account the following dynamic and static characteristics of the combustion process: ignition delay, fuel burn-up time, fuel burned dynamics, combustion energy. The simulation model of the system of the ion current integrated characteristic feedback based extreme regulation of the cyclic fuel supply is released in MATLAB. The simulation results show that the developed system of extreme regulation is capable of ensuring the operation of internal combustion engines in the region of natural extremum of the function of the ion current integral as a function of the excess air coefficient. It is also shown that the application of the method of introducing a fictitious extremum allows the engine to operate at any given air / fuel ratio within the flammability of the fuel-air mixture.