Method of modifying exhaust valve timing to improve engine performance

摘要

A method for actuating one or more exhaust valves in an internal combustion engine during positive power operation is disclosed. The expansion stroke of an engine cylinder is effectively lengthened and the exhaust stroke is effectively shortened by delaying the opening and/or advancing the closing of the exhaust valve relative to conventional exhaust valve timing during the exhaust stroke. Selective variation of the exhaust stroke during positive power operation of the engine may reduce NOx production.