Abstract: An internal combustion engine fluidly coupled to an exhaust aftertreatment system that includes an exhaust purifying device is described. A pressure monitoring device is disposed to monitor a pressure differential between an inlet and an outlet of the exhaust purifying device. A method of monitoring the exhaust purifying device includes monitoring a pressure differential between an inlet and an outlet thereof, and determining an exhaust gas flowrate associated with operation of the internal combustion engine. A raw flow resistance is dynamically determined based upon the pressure differential and the exhaust gas flowrate, and an estimated flow resistance is determined based upon the raw flow resistance. The exhaust purifying device is evaluated based upon the estimated flow resistance.

Abstract: A method and system is disclosed to test for a proper functioning of a selective catalytic reduction system of an internal combustion engine. The engine is operated at idle speed and a functionality check of the pressure sensor is executed. The engine is operated to increase an exhaust gas temperature in the exhaust pipe upstream of the catalyst and a functionality check of the pump is executed. A functionality check of the injector is executed after the functionality check of the pump and once the exhaust gas temperature has reached a predetermined target value thereof. A functionality check of the supply conduit is executed after the functionality check of the injector. The selective catalytic reduction system is identified as functioning properly when all of the functionality checks yields a positive result or malfunctioning when any one of the functionality checks yields a negative result.

Abstract: An internal combustion engine fluidly coupled to an exhaust aftertreatment system that includes an exhaust purifying device is described. A pressure monitoring device is disposed to monitor a pressure differential between an inlet and an outlet of the exhaust purifying device. A method of monitoring the exhaust purifying device includes monitoring a pressure differential between an inlet and an outlet thereof, and determining an exhaust gas flowrate associated with operation of the internal combustion engine. A raw flow resistance is dynamically determined based upon the pressure differential and the exhaust gas flowrate, and an estimated flow resistance is determined based upon the raw flow resistance. The exhaust purifying device is evaluated based upon the estimated flow resistance.

Abstract: An electronic control module for operating an internal combustion engine is disclosed. The electronic control module is configured to monitor a first air-fuel equivalence ratio of engine exhaust gases upstream of a NOx trap, and to activate a diagnostic routine for the NOx trap when the first air-fuel equivalence ratio is smaller than one. The diagnostic routine enables the electronic control module to monitor a second air-fuel equivalence ratio of engine exhaust gases downstream of the NOx trap, to use the first and second air-fuel equivalence ratios to calculate an index that is representative of the conversion efficiency of the NOx trap, and to identify a failure of the NOx trap when the efficiency index is lower than a predetermined threshold value.

Abstract: A method and system is disclosed to test for a proper functioning of a selective catalytic reduction system of an internal combustion engine. The engine is operated at idle speed and a functionality check of the pressure sensor is executed. The engine is operated to increase an exhaust gas temperature in the exhaust pipe upstream of the catalyst and a functionality check of the pump is executed. A functionality check of the injector is executed after the functionality check of the pump and once the exhaust gas temperature has reached a predetermined target value thereof. A functionality check of the supply conduit is executed after the functionality check of the injector. The selective catalytic reduction system is identified as functioning properly when all of the functionality checks yields a positive result or malfunctioning when any one of the functionality checks yields a negative result.

Abstract: A method is disclosed for controlling a concentration of oxygen that is measured by an oxygen sensor of an after-treatment system of an internal combustion engine when a regeneration of an after-treatment device is required. The method may be a computer-implement method. An oxygen sensor target value is lowered in a stepped phase as a function of an exhaust gas flow speed as the exhaust gas passes through the after-treatment system. The oxygen sensor target value is lowered evenly as a function of the exhaust gas flow speed and by a filter phase when a measured air/fuel ratio value is less than or equal to an AFR threshold value and until the oxygen sensor target value is equal to an oxygen sensor final target value. The oxygen concentration is controlled by applying the oxygen sensor target value.

Abstract: An electronic control module for operating an internal combustion engine is disclosed. The electronic control module is configured to monitor a first air-fuel equivalence ratio of engine exhaust gases upstream of a NOx trap, and to activate a diagnostic routine for the NOx trap when the first air-fuel equivalence ratio is smaller than one. The diagnostic routine enables the electronic control module to monitor a second air-fuel equivalence ratio of engine exhaust gases downstream of the NOx trap, to use the first and second air-fuel equivalence ratios to calculate an index that is representative of the conversion efficiency of the NOx trap, and to identify a failure of the NOx trap when the efficiency index is lower than a predetermined threshold value.

Abstract: A method is disclosed for controlling a concentration of oxygen that is measured by an oxygen sensor of an after-treatment system of an internal combustion engine when a regeneration of an after-treatment device is required. The method may be a computer-implement method, An oxygen sensor target value is lowered in a stepped phase as a function of an exhaust gas flow speed as the exhaust gas passes through the after-treatment system. The oxygen sensor target value is lowered evenly as a function of the exhaust gas flow speed and by a filter phase when a measured air/fuel ratio value is less than or equal to an AFR threshold value and until the oxygen sensor target value is equal to an oxygen sensor final target value. The oxygen concentration is controlled by applying the oxygen sensor target value.