Patent ID: 8899027

Claim:
A method to regenerate particulate matter (PM) in a particulate filter (PF) of a hybrid electric vehicle (HEV) having a combination of a combustion engine and an electric motor for propelling the HEV, the HEV having an electrically heated catalyst (EHC) disposed in flow communication with the PF in an exhaust system of the HEV, the method comprising: monitoring a state of the particulate filter to determine if the particulate filter requires regeneration or not; if the particulate filter is determined to not require regeneration, then continuing with the monitoring of the state of the particulate filter until it does require regeneration or until the monitoring is otherwise interrupted; if the particulate filter is determined to require regeneration, then determining whether the combustion engine is or is not combusting fuel; under a condition where the combustion engine is not combusting fuel, electrically heating the EHC until the EHC has reached a temperature suitable to cause ignition of the PM in the PF, and using the electric motor to facilitate rotation of the combustion engine at a rotational speed suitable to draw air into and be exhausted out of the combustion engine into the exhaust system, across the EHC, and into the PF to facilitate ignition of the PM in the PF; under a condition where the combustion engine is combusting fuel, setting the air-fuel ratio of the combustion engine to be about equal to a stoichiometric ratio associated with the combustion engine such that all of the oxygen used by the combustion engine for combustion of the fuel is consumed.