Internal combustion engine ignition system

摘要

An apparatus for electrically controlling the spark advance of selected cylinders of a multicylinder engine so that the spark of the selected cylinders is advanced beyond others of the cylinders. For example, the selected cylinders may be advanced beyond normal operational advance to increase combustion chamber temperatures and pressures for a relatively short period so as to clean the surfaces of the combustion chamber. The cylinders which are advanced are changed in sequence or at random so that all of the cylinders are cleaned. The system may also be used to control the spark advance of the cylinders to provide differing advances for the respective cylinders to accommodate differences in operational conditions at the cylinders.