Engine exhaust aftertreatment system architecture with coordinated emission control

An aftertreatment system for an engine comprising:

• a conduit system configured to convey an exhaust gas stream generated by the engine from the engine to atmosphere;
• a diesel oxidation catalyst (DOC) unit in the conduit system configured to convert hydrocarbons (HC);
• a selective catalyst reduction (SCR) unit in the conduit system downstream in the exhaust gas stream from the DOC unit and configured to convert nitrogen oxides (NOx);
• a passive NOx absorber (PNA) unit in the conduit system configured to store NOx and located downstream in the exhaust gas stream from the DOC unit at a location that is disposed at a distance from the engine;
• and
• at least one controller configured to:
• monitor, through signals from a sensor array, parameters of the aftertreatment system, wherein the sensor array includes temperature sensors in the conduit system;
• determine, by at least one processor, whether the PNA unit is approaching the release threshold temperature at which the PNA unit releases NOx;
• and
• control, by the at least one processor, the engine to adjust heat output from the engine to slow the heating of the PNA unit,
• wherein the distance is configured to, following a cold start of the engine, enable the SCR unit to heat to a conversion threshold temperature before the PNA unit heats to a release threshold temperature.

An aftertreatment system for an engine comprising:

• a conduit system configured to convey an exhaust gas stream generated by the engine from an exhaust manifold of the engine to atmosphere;
• a diesel oxidation catalyst (DOC) unit in the conduit system configured to convert hydrocarbons (HC);
• a selective catalyst reduction (SCR) unit in the conduit system downstream in the exhaust gas stream from the DOC unit and configured to convert nitrogen oxides (NOx);
• a passive NOx absorber (PNA) unit in the conduit system configured to store NOx in a first temperature range and configured to release the NOx in a second temperature range, the PNA unit located downstream in the exhaust gas stream from the DOC unit at a location that is disposed at a distance from the exhaust manifold of engine, wherein the distance is configured to, following a cold start of the engine, enable the SCR unit to heat to a conversion threshold temperature before the PNA unit heats to a release threshold temperature;
• an electric heater in the conduit system disposed upstream in the exhaust gas stream from the SCR unit and located downstream in the exhaust gas stream from the PNA unit;
• and
• at least one controller configured to:
• monitor, through signals from a sensor array, parameters, including temperatures, of the aftertreatment system;
• determine, by at least one processor and based on the signals, whether the PNA unit is approaching the release threshold temperature;
• determine, by the at least one processor and based on the signals, whether the SCR unit is approaching the conversion threshold temperature;
• and
• control, by the at least one processor, the engine to adjust heat output from the engine and the electric heater so that the SCR unit reaches the conversion threshold temperature before the PNA unit reaches the release threshold temperature.