Patent ID: 8042527

Claim:
A method for charging an intake manifold of an engine, comprising: adjusting an LP EGR flow rate and an uncooled HP EGR flow rate within first limits to maintain a target dilution level in the intake manifold at steady-state; adjusting the LP EGR and uncooled HP EGR rates within second limits, different from the first, to maintain the target dilution level in the intake manifold during transient conditions; and when the target dilution level is exceeded with the LP EGR and uncooled HP EGR rates at their respective lower flow-rate limits: setting the LP EGR flow rate to its lower limit; setting the uncooled HP EGR flow rate to a level that, in combination with the LP EGR flow rate at its lower limit, results in an intake-manifold dilution level approaching the target level; and enhancing a combustion stability of the engine.