IMPLEMENTING VARIABLE VALVE ACTUATION ON A DIESEL ENGINE AT HIGH-SPEED IDLE OPERATION FOR IMPROVED AFTERTREATMENT WARM-UP

Increasing engine idle speed, combined with modulating the timing of the exhaust valve during idling, increases heat transfer from the engine to aftertreatment systems to reduce the time required for the aftertreatment system to reach a minimum temperature for efficient operation. The resultant increases in heat transfer include an increase of at least 30% in the flow rate of exhaust gases and an increase of exhaust temperature by at least 25° C.