Assessment of a Strategy for Optimum Control of Ignition Advance Angle

The control of ignition timing in an internal combustion engine can improve fuel consumption. Electronic control implemented in software with a microprocessor has advantages over conventional mechanical systems. An open-loop electronic system, while incorporating an optimum profile against inlet manifold vacuum and speed, cannot readily adjust for wear. The optimum crank angle at which the peak cylinder pressure occurs has been found to be reasonably constant for a particular engine design irrespective of operating conditions. This paper presents a discussion of the use of this parameter as a measurand for a closed-loop ignition timing system. A discussion is presented of the control strategy used and results demonstrate the ability of the strategy to maintain constant the peak pressure position.