Patent ID: 8776495

Claim:
An exhaust gas after treatment system for an internal combustion engine comprising: an exhaust gas conduit in fluid communication with, and configured to receive an exhaust gas from, the internal combustion engine; an oxidation catalyst device having an inlet and an outlet in fluid communication with the exhaust gas conduit and having a first substrate, an electric heater, and a second substrate disposed serially between the inlet and the outlet, the first substrate having a larger thermal mass than the second substrate, the electric heater disposed downstream of the first substrate, and the second substrate disposed downstream of the electric heater; fuel injector coupled to and in fluid communication with the exhaust gas conduit upstream of the oxidation catalyst device for delivery of a hydrocarbon thereto and formation of an exhaust gas and hydrocarbon mixture therein; an electrical power supply connected to the electric heater and configured to raise the temperature of the heater to oxidize the hydrocarbon therein and to raise the temperature of the second substrate and the exhaust gas passing therethrough; a particulate filter device having an inlet and an outlet in fluid communication with the exhaust gas conduit downstream of the second substrate and configured to receive the heated exhaust gas therefrom; and a selective catalytic reduction catalyst applied to the particulate filter device downstream of the second substrate.