Patent ID: 7237381

Claim:
A method for operating an internal combustion engine having a turbocharger and having an after-treatment device for treating exhaust gas from the engine, wherein exhaust gas from the engine is passed through a variable-geometry mechanism of a turbine of the turbocharger and the turbine drives a compressor of the turbocharger for compressing air delivered to an intake of the engine, and the exhaust gas discharged from the turbine is delivered to the after-treatment device, the method comprising the steps of: determining an actual boost pressure of the air delivered to the intake of the engine; determining an actual temperature of the exhaust gas delivered to the after-treatment device; causing the temperature of the exhaust gas delivered to the after-treatment device to substantially match a predetermined target temperature by controlling the variable-geometry mechanism of the turbine to control the amount of power extracted by the turbine; and causing the boost pressure to substantially match a predetermined target boost pressure by either inputting mechanical power into or extracting mechanical power from the turbocharger, as required, using a power addition/extraction device coupled to the turbocharger.