Monitoring the air-fuel ratio of internal combustion engines using a neural network

Precise control of an internal combustion engine for the reduction of exhaust emissions benefits substantially from accurate measurement of the air-fuel or. ratio. This paper describes the use of the spark plug as a combustion sensor. The time-varying spark-voltage profile is acquired and used to train a neural network. The neural network is able to estimate the. ratio. Minimal additional instrumentation is required. Therefore, this method potentially provides a cheap and robust sensor for measuring the. ratio. The work described here involved devising an appropriate data acquisition system and undertaking experiments to validate the sensor technique. Vectors representing the spark-voltage profile were acquired at three different. ratio operating points and used to train and test the neural network to ascertain its ability to determine the. ratio accurately and linearly over a range. The results have supported the application of the spark-voltage profile as a means of. ratio measurement and the use of neural networks for rapid calibration of engine management systems. Potential benefits and problems of neural network analysis of spark-voltage vectors, as a means of. ratio estimation by virtual sensing, have been discussed.