Patent ID: 8010276
Filing Date: 2011-08-30
Classification: F02D,F02M,F02N,Y02T

Abstract:
1. A method for controlling an engine having a fresh air inlet and an exhaust gas recirculation (EGR) circuit, comprising the steps of: establishing a pre-selected excess oxygen ratio for combustion in the engine; establishing a mass flow of EGR gas to be delivered to the intake manifold given total mass flow of both fresh air and EGR gas and adjusting the EGR valve to pass this mass flow of EGR gas; measuring mass flow of fresh air to the intake manifold to establish a measured mass flow of fresh air; calculating a desired total mass flow of oxygen to be delivered to the intake manifold of the engine to maintain the ideal excess oxygen ratio; determining a mass flow of EGR oxygen in the mass flow of EGR gas; calculating a desired mass flow of fresh oxygen to be delivered to the intake manifold such that the sum of the desired mass flow of fresh oxygen and the mass flow of EGR oxygen is equal to the desired total mass flow of oxygen; calculating an adjusted mass flow of fresh air to supply the desired mass flow of fresh oxygen; re-adjusting the EGR valve to cause a change to the mass flow of EGR gas and a change in the measured mass flow of fresh air in the direction toward the adjusted mass flow of fresh air.