Patent ID: 8904767

Claim:
A method for achieving reduced emissions at cold start of an internal combustion engine having an exhaust gas after treatment system comprising at least one Diesel Oxygen Catalyst (DOC), at least one Diesel Particulate Filter (DPF) and a Selective Catalytic Reduction (SCR) unit, comprising the steps of: heating the at least one DOC prior to cold starting the internal combustion engine, starting and controlling the internal combustion engine towards a predetermined limit value of NOx emission when the at least one DOC has reached a predetermined DOC temperature, and optimizing fuel consumption at a predetermined total emission level when the at least one DPF and SCR have reached a predetermined temperature, at least the at least one DPF and the SCR being located successively in relation to each other and in relation to the exhaust gas after treatment system, the SCR being disposed on a substrate other than the DPF wherein the heating of the at least one DOC prior to starting the internal combustion engine is performed by cranking the internal combustion entire with an electric device with the fuel supply to the internal combustion engine shut off and with a setting chosen of the internal combustion engine so that air coming out from an outlet valve of a cylinder is higher in temperature than incoming, air through an inlet valve of the cylinder, wherein the setting is an adjustment of an exhaust valve to perform engine braking.