Inhibiting uncontrolled regeneration of a particulate filter fluidly
coupled to an exhaust manifold of an internal combustion engine may
comprise 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. Reducing the oxygen concentration of the exhaust
gas supplied to the particulate filter may include any one or combination
of reducing the oxygen concentration of intake air supplied to the intake
manifold, reducing the air portion of the air-to-fuel ratio of the
air-fuel mixture supplied to the engine and removing oxygen from the
exhaust gas supplied to the particulate filter.