Patent ID: 8584460
Filing Date: 2013-11-19
Classification: B60W,F01N,F02B,F02D,F02G,F16H,Y02T

Abstract:
1. A method for reducing an NOx content in the exhaust gas of an internal combustion engine in a vehicle, the combustion engine comprising at least one cylinder, an intake for the supply of air, an exhaust outlet for discharging exhaust gases into an exhaust after treatment system for reducing emissions of the internal combustion engine, wherein an exhaust gas recirculation supplies exhaust gas from the exhaust outlet to the intake of the internal combustion engine, and a turbine of a turbo charger and a turbine of a turbo compound as at least two energy absorbers arranged in series in the exhaust flow downstream of the exhaust outlet for absorbing energy of the exhaust gas, comprising: driving the combustion engine during at least one of a high load phase and a medium load phase at a specific power with a higher load and a lower rotational speed compared to a rotational speed commonly chosen for the specific power; overheating the exhaust gas to a first temperature by driving the internal combustion engine at the lower rotational speed which is sufficient to drive the at least two turbines and to establish a temperature of the exhaust gas downstream of the at least two turbines; cooling the overheated exhaust gas in the two turbines to a desired temperature range favourable for NOx conversion in the after treatment system; and varying the rotational speed of the internal combustion engine depending on at least one of the NOx content downstream of the after treatment system and a predicted NOx conversion possibility of the after treatment system.