Fuzzy Control of Spark Advance by Ion Current Sensing

The desired performance of a spark ignition engine is highly related to the position of the spark advance, and consequently to the beginning of the stable combustion inside cylinder. The magnitude of the generated ion current signal, measured by a sensor inside cylinder, is closely correlated to the cylinder pressure magnitude. Their maximum values almost coincide at the same crank angle position. In this paper, a feedback control system is designed to fix the position of the maximum pressure at a given desired value of the crank angle. Noting that SI engines are highly nonlinear systems, a fuzzy logic controller is developed.