Spark Advance Modeling and Control

Abstract

The spark advance determines the efficiency of spark-ignited (SI) engines by positioning the combustion in relation to the piston motion. Today’s spark-advance controllers are open-loop systems that measure parameters that effect the sparkadvance setting and compensate for their effects. Several parameters influence the best spark-advance setting but it would be too expensive to measure and account for all of them. This results in a schedule that is a compromise since it has to guarantee good performance over the range of all the non-measured parameters. A closed-loop scheme instead measures the result of the actual spark advance and maintains an optimal spark-advance setting in the presence of disturbances. To cover this area two questions must be addressed: How to determine if the spark advance is optimal and how it can be measured? This is the scope of the present work. One possible measurement is the in-cylinder pressure, which gives the torque, but also contains important information about the combustion. The cylinder pressure