Patent ID: 7631492

Claim:
A method of inhibiting uncontrolled regeneration of a particulate filter fluidly coupled to an exhaust manifold of an internal combustion engine with an exhaust gas recirculation valve fluidly coupled between the exhaust manifold and an intake manifold of the engine, the method comprising reducing an oxygen concentration of exhaust gas supplied to the particulate filter if active regeneration of the particulate filter is in progress and rotational speed of the engine speed thereafter drops to an idle speed range from an elevated rotational speed that is greater than the idle speed range, wherein reducing an oxygen concentration of the exhaust gas supplied to the particulate filter comprises reducing an oxygen concentration of intake air supplied to an intake manifold of the engine, and wherein reducing an oxygen concentration of intake air supplied to an intake manifold of the engine comprises increasing a concentration of exhaust gas in the intake air supplied to the intake manifold of the engine, and wherein increasing a concentration of exhaust gas in the intake air supplied to the intake manifold comprises controlling the exhaust gas recirculation valve to increase the concentration of exhaust gas in the intake air supplied to the intake manifold such that the oxygen concentration of the exhaust gas supplied to the particulate filter is reduced to within a target oxygen concentration range, and wherein controlling the exhaust gas recirculation valve comprises modulating exhaust gas flow through the exhaust gas recirculation valve to cycle the oxygen concentration of the exhaust gas supplied to the particulate filter between first and second oxygen concentration values that are within the target oxygen concentration range.