Use of a Variable Valve Actuation System to Control the Exhaust Gas Temperature and Space Velocity of Aftertreatment System Feedgas

A method for controlling the temperature and/or space velocity of exhaust gas passing through an aftertreatment device disposed in the exhaust system of a diesel engine provides an optimal environment for efficient conversion of NOx and undesirable emissions during transient and steady state engine operation. The method includes controlling intake and/or exhaust valve timing, either singly or in combination with fuel injection timing and selective individual cylinder cutout, in response to sensed engine operating parameters.