Study On Application Of Spark Ion Current Based On Soft-sensing Technology And Fuzzy Neural Network

With the rapid progress of modern technology, complicated-structural multi sensors used in engine impact not only the engine combustion, but also the servelife and reliability. In recent years, one of the best solution ion current, which includes lots of engine combustion and working information, is to measure engine working condition and parameters without increase of engine components. As a new industry technology with a vast development foreground, the main idea of soft-sensing, as well as fuzzy and neural networks control, which were developed at full speed, has provided a new mentality for realization of ion current used in detecting the pre-ignition value in spark plugs.This paper is based on a project of spark plug pre-ignition value comparison test which is comissioned by the Zhuzhou Torch Automobile Group CO, .LTD. The research works were expressed as:(1) Based on the concept of plasma, the mechanism of generating and disappearing of electriferous particles in gas plasma is researched and described. The mathematic models of the ignition engine's spark plug are made by synthetically applying the knowledge of chemical dynamics, thermodynamics and plasma physics.(2) Base on the fuzzy control and neural networks theory, a pre-ignition timing fuzzy control and neural networks soft-sensing model is brought up by using of the pre-ignition angle, torque and rotate speed as accessorial parameters. The simulation results show that this soft-sensing model is well mapped.(3) Base on the measurement principle of spark plug ion-current method, a system of spark plug ion-current detection and signal analysis is designed. This detection equipment has reasonable structure, low price and simple installation and is used in a test-bed experiment of a South125 single-cylinder engine.(4) The experiment results show that when the soft-sensing model is used in the pre-ignition angle controlling, successful ignition can be realized in a 96h continuous operation and ignition in one spark can be achieved in cold start condition. The engine emission can also meet the emission limit.