Control of aftertreatment of an internal combustion engine

An apparatus for controlling an aftertreatment system of an internal combustion engine, the apparatus comprising an electronic processor having an electrical input and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein, the electrical processor being configured to:

• receive a first signal from a first temperature sensor, the first signal being indicative of a first temperature of exhaust gases outputted from an internal combustion engine at a first location upstream of a first exhaust system component configured to provide a passage for exhaust gases;
• receive a second signal from a flow rate sensor, the second signal being indicative of a flow rate of the exhaust gases outputted from the engine;
• calculate an approximated value at least from the first signal and the second signal, the approximated value being indicative of a second temperature of exhaust gases at a location downstream of the first exhaust system component;
• provide an output signal to control the aftertreatment system, based on the calculated approximated value;
• receive a stored value of a concentration for each one of a plurality of exhaust gas species and calculate a rate of heat generated by chemical reactions of the exhaust gas species during the passage of the exhaust gases through the first exhaust system component;
• and
• access the memory device and execute the instructions stored therein such that it is operable to receive the first and second signals and calculate the approximated value indicative of the second temperature.