Optimal Closed-Loop Spark Control of an Automotive Engine

This work concerns the application of optimization theory to develop control laws for use in Closed-loop control strategies to minimize the effect of environmental changes, manufacturing tolerances, and time degradation. The paper describes the acquisition of engine mapping data for a 2.3L, 4 cylinder engine, the use of the data to develop analytical functions describing the fuel consumption and emissions, and the use of the functions in an optimization procedure to arrive at control strategies and driving cycle predictions of fuel consumption and emissions. The optimum schedules were then used to determine a closed-loop spark control strategy which yielded a 2% improvement in fuel economy over the open-loop control when the relative humidity was 75% at 90°F.